JP2016077888A - Absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorbent article in which an uneven structure of a surface sheet can easily follow a motion of a wearer, air permeability on a skin facing surface side is excellent, and stuffiness in a worn state hardly occurs.SOLUTION: A surface sheet 2 is made of a non-woven fabric 1 with an uneven structure, in which stripe-shaped projections 13 and recesses 14 extending in a longitudinal direction are arranged alternately in a width direction Y. The surface sheet is joined to an adjacent lower side sheet 6 in the recesses 14. The non-woven fabric 1 is made of at least a high-elongation fiber. The lower side sheet 6 is made of an aggregate of thermoplastic resin fibers. The projection 13 has a hollow structure. A fiber density of a side area 14c of the projection 13 is lower than a fiber density of an apex area 13a and a fiber density of a bottom area 13b.SELECTED DRAWING: Figure 4

Description

  The present invention relates to absorbent articles such as sanitary napkins and disposable diapers.

  As a surface sheet of an absorbent article, one having a concavo-convex structure in which streaky ridges and ridges extending in one direction are alternately arranged in the width direction is known. For example, the present applicant has proposed a surface sheet obtained by linearly bonding a sheet for forming irregularities in which a plurality of hook-shaped portions are formed in parallel to each other between the hook-shaped portions (see Patent Document 1). ).

  Patent Document 2 describes a surface sheet formed of a liquid-permeable fiber nonwoven fabric and shaped into a wave shape. The wave shape is continuously formed in the longitudinal direction of the surface sheet. The corrugated top and bottom extend in a direction intersecting the longitudinal direction of the topsheet. The density of the fibers in the wall region between the corrugated top and bottom regions is lower than the fiber density in the top or bottom region.

  Patent Document 3 describes a surface sheet having a bowl-shaped convex portion that is continuous in the longitudinal direction of the absorbent article with a predetermined interval in the width direction of the absorbent article. On both sides of each convex part, dotted concave embosses are provided alternately at the right side adjacent position and the left side adjacent position with an interval in the longitudinal direction of the absorbent article, and this concave emboss is generally staggered Is arranged.

JP 2002-165830 A JP 2008-1113866 A JP 2013-244256 A

  In the technology described in each of the patent documents described above, since the convex portion and the concave portion extending in one of the longitudinal direction and the width direction of the absorbent article are formed on the surface sheet, air permeability along that direction is ensured. However, in the direction orthogonal thereto, the convex portion becomes a ventilation barrier. As described above, in the conventional technique, it is not easy to ensure sufficient air permeability in both the longitudinal direction and the width direction on the skin facing surface side of the absorbent article.

  Therefore, the subject of this invention is providing the absorbent article which can eliminate the fault which the prior art mentioned above has.

The present invention comprises a liquid-permeable surface sheet that forms a skin contact surface, a back sheet, and an absorbent body interposed between the two sheets, and has an absorbent article having a longitudinal direction and a width direction,
The top sheet is composed of a nonwoven fabric having a concavo-convex structure in which strip-like ridges and recesses extending in the longitudinal direction are alternately arranged in the width direction, and is joined to the adjacent lower sheet in the recesses,
The nonwoven fabric is made from at least a high elongation fiber,
The lower sheet is made of an aggregate of thermoplastic resin fibers,
The ridge has a hollow structure between the nonwoven fabric and the lower sheet,
The non-woven fabric has a top region, a bottom region, and a side region located between the top region, the top portion of the convex portion is formed from the top region, and the bottom portion of the concave portion is formed from the bottom region. Has been
An absorbent article is provided in which the fiber density in the side region is lower than both the fiber density in the top region and the fiber density in the bottom region.

  ADVANTAGE OF THE INVENTION According to this invention, the uneven | corrugated structure of a surface sheet tends to follow a wearer's operation | movement, and the air permeability in the skin opposing surface side is favorable, and the absorbent article which does not occur easily in the wearing state is provided.

FIG. 1 is a perspective view showing a panty liner according to an embodiment of the present invention. 2 is an enlarged sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view of an absorber used in the panty liner shown in FIG. FIG. 4 is a partially broken perspective view showing an enlarged main part on the skin facing surface side in the panty liner shown in FIG. 1. FIG. 5 is an enlarged schematic view of the main part in FIG. FIG. 6 is a diagram for explaining a state in which the constituent fibers constituting the nonwoven fabric shown in FIG. 4 are fixed at the heat fusion part. FIG. 7 is a plan view of the skin facing surface of the panty liner shown in FIG. FIG. 8 is a schematic diagram showing a manufacturing apparatus suitably used for manufacturing the nonwoven fabric shown in FIG. 9 is a cross-sectional view taken along the line IX-IX shown in FIG. 10 (a), 10 (b) and 10 (c) illustrate how a plurality of small diameter portions and large diameter portions are formed in one constituent fiber between adjacent fused portions. It is explanatory drawing to do.

The present invention will be described below based on preferred embodiments with reference to the drawings.
FIG. 1 shows a perspective view of a panty liner 10 (hereinafter also simply referred to as “panty liner 10”) according to an embodiment of the present invention. 2 is an enlarged sectional view taken along line II-II in FIG.

  As shown in FIGS. 1 and 2, the panty liner 10 is interposed between a liquid-permeable top sheet 2 that forms a skin contact surface, a liquid-impermeable back sheet 3, and both the sheets 2 and 3. The absorbent body 4 is provided. Liquid impermeability includes liquid impermeability. The panty liner 10 has a vertically long shape, and has a longitudinal direction X and a width direction Y. The longitudinal direction X coincides with the wearer's front-rear direction when the panty liner 10 is worn, and the width direction Y is a direction orthogonal to the longitudinal direction X in the plan view of the panty liner 10. The panty liner 10 has an oval shape in plan view with a central portion in the longitudinal direction constricted.

  The top sheet 2 and the back sheet 3 are joined to each other at the peripheral edge 7 of the panty liner 10 at a portion extending from the peripheral edge of the absorber 4. The surface (non-skin contact surface) on the back sheet 3 side of the panty liner 10 is provided with an adhesive portion (not shown) for fixing to underwear such as shorts. The skin contact surface is a surface directed to the wearer's skin side when worn in the absorbent article or a component thereof, and the non-skin contact surface is the wearer's skin when worn in the absorbent article or component thereof. It is the surface that is directed to the side opposite to the skin side (usually the underwear side).

  The absorbent body 4 of the panty liner 10 is composed of an absorbent sheet 42, and more specifically, a laminate in which the absorbent sheet 42 is laminated in two or more layers. For example, as shown in FIG. 3, the laminate of two or more layers may be a laminate obtained by folding a single absorbent sheet and adhering the layers between them. A plurality of laminated sheets may be used. Moreover, it is good also as an absorber by which an additional absorptive sheet | seat is distribute | arranged to the interlayer of a laminated body of two or more layers, or one side, and one part was made thick.

  In the panty liner 10, an absorbent sheet containing a fiber material and a water-absorbing polymer is used as the absorbent sheet 42. As an absorbent sheet, it is possible to bond between constituent fibers or between constituent fibers and the water-absorbing polymer through adhesive force generated in the water-absorbing polymer in a wet state or a binder such as an adhesive or adhesive fiber added separately. A sheet or the like can be preferably used. Further, as an absorbent sheet, an absorbent sheet manufactured by the method described in JP-A-8-246395, a pulverized pulp supplied in an air stream, and a water-absorbing polymer are deposited, and then an adhesive (for example, vinyl acetate) is deposited. A dry sheet solidified with an adhesive, PVA, etc.), an absorbent sheet obtained by applying a hot-melt adhesive between paper and non-woven fabric and then spraying a superabsorbent polymer, spunbond or melt blown non-woven fabric An absorbent sheet obtained by blending a highly water-absorbing polymer during the process can also be used. These absorbent sheets can also be used as an absorber having a single layer structure without being laminated in two or more layers. In addition, the layers between the layers may not be bonded.

The thickness of the absorber 4 is preferably 0.1 mm or more, more preferably 0.5 mm or more, preferably 5 mm or less, more preferably 2 mm or less, and preferably 0.1 mm or more and 5 mm or less, more preferably. Is 0.5 mm or more and 2 mm or less. The thickness of the absorber 4 is measured by the following method.
The thickness T is measured using a peacock precision measuring instrument (model R1-C) which is a micrometer having two parallel pressing surfaces (a fixed pressing surface and a movable pressing surface). The diameter of the measuring element movable pressing surface is 5 mm, and the pressure is 100 kPa or less. The size of the test specimen for measurement is not less than the size of the following plate. A 20 mm × 20 mm plate (mass 5.4 g) is placed on the test piece, the measuring element movable pressurizing surface is operated at a speed of 2 mm / s, applied to the plate, and the value immediately after stabilization is read. The pressure between the pressing surfaces (pressure applied to the test piece) is 1.3 kPa or less.

  As the forming material of the back sheet 3, various materials conventionally used for the back sheet of the absorbent article can be used without particular limitation. For example, a liquid-impermeable or water-repellent resin film, a resin film, A laminate sheet with a non-woven fabric can be used.

  As shown in FIGS. 2 and 4, the topsheet 2 in the panty liner 10 of the present embodiment has a concavo-convex structure in which streaky ridges 13 and ridges 14 extending in one direction are alternately arranged in the width direction. It is comprised from the nonwoven fabric 1 of this. Moreover, as shown in FIG.2 and FIG.4, the surface sheet 2 is joined in the concave strip part 14 in the adjacent lower sheet 6 and the joint part 14s, and the convex strip part 13 is the nonwoven fabric 1 and lower side. The sheet 6 has a hollow structure. The nonwoven fabric 1 which comprises the surface sheet 2 contains the fiber 11 which has the large diameter part 17 and the small diameter parts 16 and 16 from which a fiber diameter mutually differs, as shown in FIG. 6 mentioned later.

The non-woven fabric 1 constituting the top sheet 2 will be described in more detail.
FIG. 4 shows a perspective view of a nonwoven fabric 1 (hereinafter also referred to as “nonwoven fabric 1”) used as the top sheet 2 in the panty liner 10 of the present embodiment. FIG. 5 is a schematic diagram showing a cross section in the thickness direction of the nonwoven fabric 1 shown in FIG. 4. FIG. 6 is an enlarged schematic view of the constituent fibers 11 of the nonwoven fabric 1 shown in FIG. As shown in FIG. 4, the nonwoven fabric 1 is a nonwoven fabric provided with a plurality of fusion portions 12 (see FIG. 6) formed by heat-sealing the intersections of the constituent fibers 11. Moreover, in the nonwoven fabric 1, as shown in FIG. 4, "one direction" from which the protruding line part 13 and the recessed line part 14 extend is the same direction as the longitudinal direction X of the panty liner 10, and is one direction (X direction). Also written.

  More specifically, as shown in FIG. 5, the nonwoven fabric 1 has a plurality of ridge portions 13 in which the cross-sectional shapes of the front and back surfaces a and b are convex upward in the thickness direction (Z direction), It has the concave line part 14 located between adjacent convex line parts 13 and 13. FIG. As for the concave-line part 14, the cross-sectional shape of front and back both surfaces a and b has comprised the concave shape toward the upper direction of the thickness direction (Z direction) of a nonwoven fabric. In other words, as for the concave stripe part 14, the cross-sectional shape of front and back both surfaces a and b has comprised the convex shape toward the downward direction of the thickness direction (Z direction) of a nonwoven fabric. Each of the plurality of ridges 13 extends continuously in one direction (X direction) of the nonwoven fabric 1, and each of the plurality of ridges 14 extends continuously in one direction X of the nonwoven fabric 1. I am doing. The ridges 13 and the ridges 14 are parallel to each other and are alternately arranged in a direction (Y direction) orthogonal to the one direction (X direction).

  As shown in FIG. 5, the nonwoven fabric 1 includes a top region 13 a, a bottom region 13 b, and a side region 13 c located between these when the nonwoven fabric 1 is viewed in cross section along the thickness direction Z. The top region 13a, the bottom region 13b, and the side region 13c extend continuously in one direction (X direction) of the nonwoven fabric 1. The top region 13a, the bottom region 13b, and the side region 13c, when the nonwoven fabric 1 is viewed in a cross-section along the thickness direction Z, divides the thickness of the nonwoven fabric 1 in the Z direction into three equal parts, The top region 13a is distinguished from the central region as the side region 13c and the lower region as the bottom region 13b. The top of the ridge 13 is formed from a top region 13a. The bottom part of the concave line part 14 is formed from the bottom part area | region 13b.

  As will be described later, the nonwoven fabric 1 is manufactured by subjecting the fiber sheet 1a to a concavo-convex process using a pair of concavo-convex rolls 401 and 402 meshing with each other. The longitudinal direction X of the nonwoven fabric 1 described above is the same direction as the machine direction (MD, flow direction) when the nonwoven fabric 1 is manufactured by performing uneven processing on the fiber sheet 1a (see FIG. 8). The direction Y orthogonal to the X direction is the same direction as the orthogonal direction (CD, roll axis direction) orthogonal to the machine direction (MD, flow direction).

  As shown in FIG. 5, when the nonwoven fabric 1 is observed along the thickness direction Z, the fiber density of the side region 13c is lower than the fiber density of the top region 13a and the fiber density of the bottom region 13b. The fiber density is the number of fibers per unit area in the cross section of the nonwoven fabric 1. Therefore, the side region 13c is a sparse region in which the number of fibers is small (the interfiber distance is large) compared to the top region 13a and the bottom region 13b. Due to this, the side region 13c has higher air permeability than the top region 13a and the bottom region 13b. As a result, the panty liner of the present embodiment using the nonwoven fabric 1 as the top sheet 2 circulates along the concave strip portion 14 in the mounted state, and in the convex strip portion 13 through the side region 13c. The air flows in the direction orthogonal to the ridges 13. Thus, since the panty liner of this embodiment has a structure in which air flows in both the longitudinal direction X and the width direction Y on the skin facing surface side, the air permeability on the skin facing surface side is good. Thus, it is difficult for the stuffiness to occur when worn. Moreover, since the ridges 13 and the ridges 14 made of the nonwoven fabric 1 are alternately formed, the concavo-convex structure of the topsheet 2 can easily follow the movement of the wearer when the panty liner 10 is worn, The hit is good.

  In particular, as shown in FIG. 1, each side edge of the panty liner 10 has a curved shape, and in the longitudinal direction front area 10A and the rear area 10B, each side edge is convex outward in the width direction. In the longitudinal central region 10C, each side edge is curved in a convex shape toward the inner side in the width direction, so that the width in the longitudinal central region 10C is the narrowest. It becomes easy to efficiently discharge water vapor toward the outside in the direction Y. This also makes it difficult for the panty liner 10 to be stuffy when worn.

The ratio (D _13c / D _13a , D _13c / D _13a ) of the fiber density (D _13c ) of the side region 13c to the fiber density (D _13a ) in the top region 13a or the fiber density (D _13b ) in the bottom region 13b ) Is preferably 0.15 or more and 0.9 or less, more preferably 0.2 or more and 0.8 or less. Specifically, the value of the fiber density of the nonwoven fabric 1 is such that the fiber density (D _13a ) in the top region 13a is preferably 90 / mm ² or more and 200 / mm ² or less, more preferably 100 / mm ² or more. 180 pieces / mm ² or less. Also, the fiber density _{(D 13b)} at the bottom area 13b is preferably 80 present / mm ² or more 200 present / mm ² or less, more preferably 90 present / mm ² or more 180 lines / mm ² or less. The fiber density of the side region 13c _{(D 13c)} is preferably 30 lines / mm ² or more eighty / mm ² or less, more preferably 40 present / mm ² or more 70 yarns / mm ² or less. The method for measuring the fiber density is as follows.

[Measuring method of fiber density in top region 13a, bottom region 13b and side region 13c]
The nonwoven fabric is cut along the thickness direction Z using a feather razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.). Regarding the fiber density in the top region 13a, the top region 13a, which is the upper part when the thickness of the cut surface of the nonwoven fabric is divided into three equal parts in the Z direction, is magnified using a scanning electron microscope (fiber cross section is 30 to 30). The magnification is adjusted so that about 60 fibers can be measured (150 to 500 times), and the number of cross-sections of the fibers cut by the cut surface per fixed area (about 0.5 mm ² ) is counted. Next, it converts into the number of cross sections of the fiber per 1 mm < ² >, and makes this the fiber density in the top region 13a. The measurement is performed at three locations, and the average is the fiber density of the sample. Similarly, the fiber density in the bottom region 13b is obtained by measuring the lower part when the thickness of the cut surface of the nonwoven fabric is divided into three equal parts in the Z direction. Similarly, the fiber density of the side region 13c is obtained by measuring the central portion when the thickness of the cut surface of the nonwoven fabric is divided into three equal parts in the Z direction. Note that JCM-5100 (trade name) manufactured by JEOL Ltd. is used as the scanning electron microscope.

As described above, the fiber density _{(D 13c)} of the side region 13c in the convex portion 13 is preferably 30 present / mm ² or more eighty / mm ² or less, more preferably 40 present / mm ² or more 70 lines / mm ² or less. That is, although the fiber density in the side region 13c is preferably lower than the fiber density in the top region 13a and the bottom region 13b, the fiber density in the side region 13c is preferably not zero. In other words, the fiber density of the side region 13c is preferably greater than 0 / mm ² . That the fiber density of the side region 13c is zero means that a through hole is formed in the side region 13c. Therefore, in this embodiment, it is preferable that no through hole is formed in the side region 13c. When the fiber density of the side region 13c is zero, that is, when a through hole is formed in the side region 13c, liquid return is likely to occur through the through hole, or the ridge 13 is likely to be crushed. Or If the number of through-holes formed is reduced in order to prevent the inconvenience caused by forming these through-holes, the air flowability in the direction perpendicular to the ridges 13 is reduced due to this. End up. In this way, there are various inconveniences in forming the through hole in the side region 13c, but if the fiber density of the side region 13c is lowered as in this embodiment, the liquid return and the ridges are formed. There is an advantage that air flowability in a direction orthogonal to the ridges 13 can be ensured while preventing the crushing of 13.

  The concavo-convex structure of the nonwoven fabric 1 composed of the ridges 13 and the ridges 14 is preferably formed at least in the central region in the width direction Y of the panty liner 1. As a result, the uneven structure can be provided in a portion that is most likely to come into contact with the skin of the wearer, so that the above-described effect of preventing stuffiness and the effect of following the operation of the wearer are reliably exhibited. In particular, it is preferable that the topsheet 2 has a concavo-convex structure in the entire region inside the peripheral portion 7 (see FIG. 1) from the viewpoint that these effects become more remarkable.

  In the panty liner 10 of the present embodiment, at least in the central region 10C in the longitudinal direction, each side edge 4a of the absorbent body 4 is linear, and the extending direction of the side edge 4a is defined as the concavo-convex structure, that is, the ridge portion. It is preferable to make it substantially parallel to the direction in which 13 and the recessed line portion 14 extend. By doing so, the topsheet 2 is easily bent at the side edge 4a of the absorber 4, and the discomfort of the panty liner 10 is reduced. The term “substantially parallel” includes a case where they are completely parallel and a case where the angles intersect within 3 degrees.

The constituent fibers 11 of the nonwoven fabric 1 include high elongation fibers. Here, the high elongation fiber included in the constituent fiber 11 means not only a fiber having a high elongation at the raw material fiber stage, but also a fiber having a high elongation at the stage of the produced nonwoven fabric 1. As the “high elongation fiber”, excluding stretchable fibers that have elasticity (elastomer) and expand and contract, for example, paragraph [0] of JP 2010-168715 A
033], a composite fiber is obtained by melt spinning at a low speed, and then the heat treatment and / or crimping treatment is performed without performing a stretching treatment. A heat-extensible fiber with a long length, a fiber produced under a relatively low spinning speed using a resin such as polypropylene or polyethylene, or a polyethylene-polypropylene copolymer having a low crystallinity, or Examples thereof include fibers produced by dry blending and spinning polyethylene and polypropylene. Among these fibers, the high elongation fiber is preferably a core-sheath type composite fiber having heat-fusibility. The core-sheath type composite fiber may be a concentric core-sheath type, an eccentric core-sheath type, a side-by-side type, or a deformed type, but is preferably a concentric core-sheath type. Whatever form the fiber takes, from the viewpoint of producing a nonwoven fabric that is soft and soft to the touch, the fineness of the high elongation fiber is 1.0 dtex or more and 10.0 dtex or less at the raw material stage. Is preferable, and more preferably 2.0 dtex or more and 8.0 dtex or less.

  The constituent fibers 11 of the nonwoven fabric 1 may be configured to include other fibers in addition to the high elongation fibers, but are preferably configured only from the high elongation fibers. Other fibers include, for example, a non-heat-extensible core-sheath type heat-fusible composite fiber containing two components having different melting points, or a fiber that does not inherently have heat-fusibility ( Examples thereof include natural fibers such as cotton and pulp, rayon and acetate fibers). When the nonwoven fabric 1 is configured to include other fibers in addition to the high elongation fibers, the proportion of the high elongation fibers in the nonwoven fabric 1 is preferably 50% by mass to 100% by mass, and more preferably 80%. It is not less than 100% by mass.

  The heat-stretchable composite fiber that is a high-stretch fiber is a composite fiber that has been subjected to an unstretched or weakly stretched treatment at the raw material stage. For example, the first resin component constituting the core portion and the sheath portion And a second resin component including a polyethylene resin, and the first resin component has a higher melting point than the second resin component. A 1st resin component is a component which expresses the heat | fever extensibility of this fiber, and a 2nd resin component is a component which expresses heat-fusibility. The melting points of the first resin component and the second resin component were determined by thermal analysis of a finely cut fiber sample (sample weight 2 mg) using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.) at a heating rate of 10 ° C./min. The melting peak temperature of each resin is measured and defined by the melting peak temperature. When the melting point of the second resin component cannot be clearly measured by this method, the resin is defined as “resin having no melting point”. In this case, the temperature at which the second resin component is fused to such an extent that the strength of the fusion point of the fiber can be measured is used as the temperature at which the molecular flow of the second resin component begins, and this is used instead of the melting point.

As above-mentioned as a 2nd resin component which comprises a sheath part, the polyethylene resin is included. Examples of the polyethylene resin include low density polyethylene (LDPE), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE). In particular, a high density polyethylene having a density of 0.935 g / cm ³ or more and 0.965 g / cm ³ or less is preferable. The second resin component constituting the sheath is preferably a polyethylene resin alone, but other resins can also be blended. Other resins to be blended include polypropylene resin, ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), and the like. However, as for the 2nd resin component which comprises a sheath part, it is preferable that 50 mass% or more in the resin component of a sheath part is 70 to 100 mass% especially polyethylene resin. The polyethylene resin preferably has a crystallite size of 10 nm or more and 20 nm or less, and more preferably 11.5 nm or more and 18 nm or less.

  As a 1st resin component which comprises a core part, the resin component whose melting | fusing point is higher than the polyethylene resin which is a constituent resin of a sheath part can be especially used without a restriction | limiting. Examples of the resin component constituting the core include polyolefin resins such as polypropylene (PP) (excluding polyethylene resin), polyester resins such as polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Furthermore, polyamide-based polymers, copolymers having two or more resin components, and the like can also be used. A plurality of types of resins can be blended and used. In this case, the melting point of the core is the melting point of the resin having the highest melting point. Since the production of the nonwoven fabric becomes easy, the difference (the former-the latter) between the melting point of the first resin component constituting the core part and the melting point of the second resin component constituting the sheath part is 20 ° C. or higher. It is preferable that it is 150 degrees C or less.

  The preferred orientation index of the first resin component in the heat-stretchable composite fiber, which is a high elongation fiber, is naturally different depending on the resin used. For example, when the first resin component is a polypropylene resin, the orientation index is 60% or less. Is preferable, more preferably 40% or less, and still more preferably 25% or less. When the first resin component is polyester, the orientation index is preferably 25% or less, more preferably 20% or less, and still more preferably 10% or less. On the other hand, the second resin component preferably has an orientation index of 5% or more, more preferably 15% or more, and still more preferably 30% or more. The orientation index is an index of the degree of orientation of the polymer chain of the resin constituting the fiber. And when the orientation index of a 1st resin component and a 2nd resin component is each said value, a heat | fever extensible composite fiber comes to expand | extend by heating.

  The orientation index of the first resin component and the second resin component is determined by the method described in paragraphs [0027] to [0029] of JP2010-168715A. Moreover, the method in which each resin component in the thermally stretchable conjugate fiber achieves the orientation index as described above is described in paragraphs [0033] to [0036] of JP-A No. 2010-168715.

  Further, the elongation of the high elongation fiber is preferably 100% or more, particularly 200% or more, particularly 250% or more at the raw material stage. The elongation of the high elongation fiber is preferably 800% or less, particularly 500% or less, particularly 400% or less at the raw material stage. Specifically, the elongation of the high elongation fiber is preferably 100% or more and 800% or less, more preferably 200% or more and 500% or less, and further preferably 250% or more and 400% or less at the raw material stage. It is. By using the high elongation fiber having the elongation in this range, the fiber is successfully stretched in the stretching apparatus, and the changing point from the small diameter portion to the large diameter portion described above is adjacent to the fusion portion. , The touch becomes good.

  The elongation of the high elongation fiber conforms to JISL-1015, and the measurement is based on the measurement environment temperature and humidity of 20 ± 2 ° C, 65 ± 2% RH, the tensile tester gripping distance of 20mm, and the tensile speed of 20mm / min. And In addition, when collecting fibers from an already manufactured non-woven fabric and measuring the elongation, when the gripping interval cannot be 20 mm, that is, when the length of the fiber to be measured is less than 20 mm, the gripping interval is set. Measure by setting to 10 mm or 5 mm.

  The ratio (mass ratio, former: latter) of the first resin component and the second resin component in the heat-extensible composite fiber that is a high elongation fiber is 10:90 to 90:10, particularly 20: at the raw material stage. It is preferable that it is 80-80: 20, especially 50: 50-70: 30. As the fiber length of the heat-extensible conjugate fiber, one having an appropriate length is used according to the method for producing the nonwoven fabric. For example, when the nonwoven fabric is manufactured by the card method as described later, the fiber length is preferably about 30 to 70 mm.

  The fiber diameter of the heat-extensible composite fiber, which is a high elongation fiber, is appropriately selected according to the specific use of the nonwoven fabric at the raw material stage. When the nonwoven fabric is used as a constituent member of an absorbent article such as a surface sheet of the absorbent article, it is preferable to use a nonwoven fabric having a size of 10 μm to 35 μm, particularly 15 μm to 30 μm. The fiber diameter is measured by the following method.

[Measurement of fiber diameter]
As the fiber diameter of the fiber, the fiber diameter (μm) is measured by magnifying the cross section of the fiber 200 to 800 times using a microscope VH-8000 (manufactured by Keyence Corporation). The cross section of the fiber is obtained by cutting the fiber using a feather razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.). For each extracted fiber, the fiber diameter when approximated to a circle is measured at five locations, and the average value of the five measured values is taken as the fiber diameter.

  In the raw material stage, as the heat-extensible conjugate fiber that is a high elongation fiber, in addition to the above-described heat-extensible conjugate fiber, Japanese Patent No. 4131852, Japanese Patent Laid-Open No. 2005-350836, Japanese Patent Laid-Open No. 2007-303035 The fibers described in JP-A No. 2007-204899, JP-A 2007-204901, JP-A 2007-204902, and the like can also be used.

As shown in FIG. 6, the nonwoven fabric 1 pays attention to one constituent fiber 11 among the constituent fibers 11 of the nonwoven fabric 1, and the constituent fiber 11 is between the adjacent fusion portions 12, 12. It is preferable to have a large diameter portion 17 having a large fiber diameter sandwiched between two small diameter portions 16 and 16 having a small fiber diameter. Specifically, as shown in FIG. 6, paying attention to one constituent fiber 11 of the constituent fibers 11 of the nonwoven fabric 1, a fusion formed by heat-sealing the intersection with the other constituent fibers 11. A small diameter portion 16 having a small fiber diameter extends from the landing portion 12 with substantially the same fiber diameter. Then, paying attention to the single constituent fiber 11, the large-diameter portion 17 having a fiber diameter larger than that of the small-diameter portion 16 between the small-diameter portions 16 and 16 extending from the adjacent fusion portions 12 and 12. Are extended with substantially the same fiber diameter. Specifically, the non-woven fabric 1 focuses on one constituent fiber 11, and from one of the adjacent fused portions 12, 12 toward the other fused portion 12, It has constituent fibers 11 arranged in the order of a small diameter portion 16 on the side of the attachment portion 12, one large diameter portion 17, and a small diameter portion 16 on the side of the other fusion portion 12.
As described above, the presence of the low-rigidity small-diameter portion 16 adjacent to the fused portion 12, which is a portion where the stiffness of the nonwoven fabric 1 is increased, improves the flexibility of the nonwoven fabric 1 and improves the touch. . Moreover, the softness | flexibility of the nonwoven fabric 1 improves further and the touch becomes still more favorable, so that the small diameter part 16 with low rigidity is provided in the component fiber 11 in multiple numbers.

  As shown in FIG. 6, the nonwoven fabric 1 focuses on one constituent fiber 11 among the constituent fibers 11 of the nonwoven fabric 1, and includes a plurality of large-diameter portions 17 between the adjacent fusion portions 12 and 12. (2 in the nonwoven fabric 1) It has the constituent fiber 11 provided. Specifically, the non-woven fabric 1 focuses on one constituent fiber 11, and from one of the adjacent fused portions 12, 12 toward the other fused portion 12, Constituent fibers arranged in the order of the small-diameter portion 16 on the bonding portion 12 side, the first large-diameter portion 17, the small-diameter portion 16, the second large-diameter portion 17, and the small-diameter portion 16 on the other fused portion 12 side 11. The non-woven fabric 1 is provided with one or more large-diameter portions 17 between adjacent fused portions 12 and 12 with a focus on one constituent fiber 11, and more preferably one or more. It is preferable that three or less are provided from the viewpoint of improving the touch and reducing the strength of the nonwoven fabric.

The ratio (L ₁₆ / L ₁₇ ) of the fiber diameter (diameter L ₁₆ ) of the small diameter portion 16 to the fiber diameter (diameter L ₁₇ ) of the large diameter portion 17 is preferably 0.5 or more and 0.8 or less, more preferably 0. .55 or more and 0.7 or less. Specifically, the fiber diameter (diameter L ₁₆ ) of the small-diameter portion 16 is preferably 5 μm or more and 28 μm or less, more preferably 6.5 μm or more and 20 μm or less, and particularly preferably 7.5 μm or more and 16 μm or less from the viewpoint of improving the touch. is there. The fiber diameter (diameter L ₁₇ ) of the large diameter portion 17 is preferably 10 μm or more and 35 μm or less, more preferably 13 μm or more and 25 μm or less, and particularly preferably 15 μm or more and 20 μm or less from the viewpoint of improving the touch.
The fiber diameters (the diameters L ₁₆ and L ₁₇ ) of the small diameter part 16 and the large diameter part 17 are measured in the same manner as the fiber diameter measurement described above.

  In addition, as shown in FIG. 6, the nonwoven fabric 1 pays attention to one constituent fiber 11 among the constituent fibers 11 of the nonwoven fabric 1, from the small diameter portion 16 adjacent to the fused portion 12 to the large diameter portion 17. It is preferable that the change point 18 is arranged within a range of １ ／ of the interval T between the fusion parts 12, 12 adjacent to the fusion part 12. Here, the change point 18 of the nonwoven fabric 1 is a gradual change continuously from the small diameter portion 16 extending with a small fiber diameter to the large diameter portion 17 extending with a fiber diameter larger than the small diameter portion 16. This means a portion where the fiber diameter changes extremely in one step without including a portion that continuously changes over a plurality of stages. Moreover, when the said one component fiber 11 is a heat | fever extensible composite fiber, the change point 18 of the nonwoven fabric 1 is the 1st resin component which comprises a core part, and the 2nd resin component which comprises a sheath part. It does not include a state in which the fiber diameter is changed by peeling between the layers, and it means a portion where the fiber diameter is changed by stretching.

  Further, the fact that the changing point 18 is arranged within a range of 1/3 of the interval T between the adjacent fused portions 12 and 12 from the fused portion 12 means that the constituent fibers 11 of the nonwoven fabric 1 are randomly extracted. As shown in FIG. 6, the constituent fiber 11 is made of JCM-5100 (trade name) manufactured by JEOL Ltd. as a scanning electron microscope. Magnify and observe (100 to 300 times) so that it can be observed. Next, the interval T between the centers of the adjacent fused portions 12 and 12 is divided into three equal parts, and the region AT on the side of one fused portion 12, the region BT on the side of the other fused portion 12, and the center region CT Break down. This means that the change point 18 is arranged in the area AT or the area BT. Further, the non-woven fabric 1 in which the changing point 18 is disposed within a range of 1/3 of the interval T between the adjacent fused portions 12, 12 from the fused portion 12 is the number of the constituent fibers 11 of the non-woven fabric 1 20. When extracted randomly, the constituent fiber 11 in which the change point 18 is arranged in the region AT or the region BT means a nonwoven fabric having at least one of the 20 constituent fibers 11. Specifically, from the viewpoint of improving the touch, it is preferably 1 or more, more preferably 5 or more, and particularly preferably 10 or more.

In the non-woven fabric 1, the number of fibers having a change point 18 in the constituent fibers 11 constituting the side region 13c is the number of fibers having the change point 18 in the constituent fibers 11 constituting the top region 13a, and the bottom region 13b. Is formed more than the number of fibers having the change point 18 in the constituent fibers 11 constituting the. The number of fibers having the change point 18 in the constituent fibers 11 constituting the top region 13a (N _13a ) or the side region with respect to the number of fibers having the change point 18 in the constituting fibers 11 constituting the bottom region 13b (N _13b ) The ratio (N _13c / N _13a , N _13c / N _13a ) of the number of fibers (N _13c ) having the change point 18 in the constituent fibers 11 constituting _13c is preferably 2 or more and 20 or less, more preferably 5 or more and 20 or less. It is. Specifically, regarding the specific value of the number of fibers having the change point 18 of the nonwoven fabric 1, the number of fibers having the change point 18 (N _13c ) in the constituent fibers 11 constituting the side region 13c is preferably 5 The number is 20 or more and 20 or less, more preferably 10 or more and 20 or less. Further, the number (N _13a ) of fibers having the change point 18 in the constituent fibers 11 constituting the top region 13a is preferably 1 or more and 15 or less, more preferably 5 or more and 15 or less. Further, the number (N _13b ) of fibers having the change point 18 in the constituent fibers 11 constituting the bottom region 13b is preferably 1 or more and 15 or less, more preferably 5 or more and 15 or less. The method for measuring the number of fibers having the change point 18 is as follows.

[Measurement method of the number of fibers having the change point 18 in the constituent fibers constituting the top region 13a, the bottom region 13b, or the side region 13c]
Regarding the number of fibers having the change point 18 in the constituent fibers 11 constituting the top region 13a, the vicinity of the top of the top region 13a, which is an upper part when the thickness of the nonwoven fabric is divided into three equal parts in the Z direction, The fiber cross section is enlarged (adjusted to a magnification capable of measuring about 30 to 60 fiber cross sections; 50 to 500 times), 20 constituent fibers 11 constituting the top region 13a are randomly extracted, and 20 constituent fibers 11 are extracted. The number of fibers having the change point 18 in the is counted. This is the number of fibers having a change point 18 in the constituent fibers constituting the top region 13a. The measurement is performed at three places, and the average is the number of fibers having the change point 18 in the constituent fibers constituting the top region 13a of the sample. Similarly, regarding the number of fibers having the change point 18 in the constituent fibers 11 constituting the bottom region 13b, the vicinity of the bottom point of the bottom region 13b, which is a lower part when the thickness of the nonwoven fabric is equally divided into three in the Z direction, Determine by measuring. Similarly, the number of fibers having the change point 18 in the constituent fibers 11 constituting the side region 13c is obtained by measuring the central portion when the thickness of the nonwoven fabric is equally divided into three in the Z direction. Note that JCM-5100 (trade name) manufactured by JEOL Ltd. is used as the scanning electron microscope.

The thickness of the nonwoven fabric 1, the entire thickness of when the side view of the nonwoven fabric 1 and the sheet thickness T _S, the local thickness of the nonwoven fabric 1 that is curved to the irregularities and the layer thickness T _L. Sheet thickness _{T S} is may be adjusted as appropriate depending on the application, when used as a topsheet or sublayer of the absorbent article, preferably 0.5mm or more 7mm or less, more preferably 5mm or 1.0 mm. By setting it as this range, the bodily fluid absorption speed | velocity at the time of use is quick, the liquid return from an absorber is suppressed, and also moderate cushioning property is realizable. Moreover, even if a load is added, the shape of the protruding item | line part 13 can be maintained.

The layer thickness _TL may be different at each site in the nonwoven fabric 1 and may be appropriately adjusted depending on the application. The layer thickness T _L1 of the top region 13a is preferably 0.1 mm or greater and 3.0 mm or less, and more preferably 0.2 mm or greater and 2.0 mm or less. The layer thickness T _L2 of the bottom region 13b is preferably 0.1 mm or greater and 3.0 mm or less, and more preferably 0.2 mm or greater and 2.0 mm or less. The layer thickness T _L3 of the side region 13c is preferably 0.1 mm or greater and 3.0 mm or less, and more preferably 0.2 mm or greater and 2.0 mm or less. The relationship between the layer thicknesses T _L1 , T _L2 , and T _L3 is within this range, so that the body fluid absorption speed during use is fast, the liquid return from the absorber is suppressed, and an appropriate cushioning property is realized. it can.

The sheet thickness T _S and the layer thickness T _L are measured by the following methods.
Method of measuring the thickness of the sheet T _S is in a state of applying a load of 0.05kPa nonwoven 1 is measured using a thickness gauge. A laser displacement meter manufactured by OMRON Corporation is used for the thickness measuring instrument. Thickness is measured at 10 points, and the average value is calculated as the thickness.
Layer thickness T _L of assay, by expanding the cross section of the sheet by Keyence digital microscope VHX-900 by about 20 times, to measure the thickness of each layer.

  When the nonwoven fabric 1 is viewed in plan, the pitch between the tops of the ridges 13 adjacent in the Y direction is preferably 1 mm or more and 15 mm or less, and more preferably 1.5 mm or more and 10 mm or less. The height H (see FIG. 4) of the ridge 13 is preferably 0.5 mm to 5 mm, and more preferably 1 mm to 3 mm. The height H is measured under a no load by observing a cross section in the thickness direction Z of the nonwoven fabric 1 with a microscope.

The basis weight of the nonwoven fabric 1 is preferably 15 g / ^{m 2} or more 50 g / ^{m 2} or less the average value of the entire, 20 g / ^{m 2} or more 40 g / ^{m 2} or less is more preferable.

  A small amount of fiber treatment agent such as fiber colorant, antistatic property agent, lubricant, hydrophilic agent may be adhered to the surface of the constituent fiber 11 of the nonwoven fabric 1 at the raw material stage.

  As a method for attaching the fiber treatment agent to the surface of the constituent fiber 11, various known methods can be employed without any particular limitation. For example, application by spraying, application by a slot coater, application by roll transfer, immersion in a fiber treatment agent, and the like can be mentioned. These treatments may be performed on the fibers before being made into a web, or after the fibers are made into a web by various methods. However, it is necessary to perform the process before the hot air blowing process described later. The fiber having the fiber treatment agent attached to the surface is dried at a temperature sufficiently lower than the melting point of the polyethylene resin (for example, 120 ° C. or less) by, for example, a hot air blowing type dryer.

  As shown in FIGS. 2 and 4, the top sheet 2 in the panty liner 10 of the present embodiment is heat-sealed with the adjacent lower sheet 6 in each of the concave portions 14 of the nonwoven fabric 1 constituting the top sheet 2. Are joined by. The lower sheet 6 in the present embodiment is a second sheet 6 made of an aggregate of thermoplastic resin fibers disposed between the top sheet 2 and the absorber 4. As the aggregate of thermoplastic resin fibers, a nonwoven fabric can be generally used.

  The concave strip portion 14 of the surface sheet 2 is continuously joined to the second sheet 6 in the longitudinal direction of the panty liner 10, and the joint portion 14s extends between the seal portions 7 located at both ends in the longitudinal direction. In the meantime, it can be intermittently formed along the longitudinal direction X of the panty liner 10. By intermittently joining the top sheet 2 and the second sheet 6, air permeability between the two sheets can be ensured, and the stuffiness when the panty liner 10 is attached can be further reduced. However, it is not hindered to continuously join the top sheet 2 and the second sheet 6 over the entire area in the longitudinal direction X.

  The joining of the top sheet 2 and the second sheet 6 is not limited to the above-described heat fusion, and other joining means such as joining with an adhesive such as a hot melt adhesive may be employed. The second sheet 6 can be made shorter in the longitudinal direction X and the width direction Y than the top sheet 2. Alternatively, the length of the second sheet 6 in the longitudinal direction X and the width direction Y can be the same as that of the top sheet 2.

When the topsheet 2 having the concavo-convex structure is joined to the flat second sheet 6, the concavo-convex structure of the topsheet 2 is not easily crushed even if a load is applied thereto. For example, in a state where a load of 4 g / cm ² is applied to the panty liner 10 from the surface sheet 2 side, it is preferable that the ridge portion can maintain its hollow structure, and a state where a load of 20 g / cm ² is applied. And it is still more preferable that a protruding item | line part is what can maintain the hollow structure. “A hollow structure can be maintained” means that even after a load is applied, a space exists in the ridge 13 and the shape of the space is allowed to be deformed before the load is applied. The Whether or not there is a space inside the ridge 13 is determined by cutting the joined body of the top sheet and the second sheet 6 along the thickness direction Z to form a cross section, and observing the cross section with a microscope. Check. The load of 4 g / cm ² assumes a pressure applied to the panty liner 10 when the panty liner 10 is attached to the shorts and the shorts are worn. The load of 20 g / cm ² assumes a pressure applied to the panty liner 10 when the wearer sits on the chair in the wearing state of the panty liner 10.

  The fact that the ridges 13 are not easily crushed with respect to the load also contributes to the fact that the constituent fibers of the nonwoven fabric 1 are high elongation fibers. In detail, in the manufacturing method of the nonwoven fabric 1 mentioned later, when the fiber sheet 1a (refer FIG. 8) is extended | stretched and the nonwoven fabric 1 is manufactured, if a fiber will be cut | disconnected by extending | stretching, the protruding item | line part 13 will be formed. Even so, the strength against compression is reduced. On the other hand, by using the high elongation fiber, the fiber is less likely to be cut in the drawing process of the fiber sheet 1a, and the low-fiber density side region 13c is successfully formed while The strength reduction can be effectively prevented.

  Nonwoven fabrics obtained by various production methods can be used as the aggregate of thermoplastic resin fibers constituting the second sheet 6. For example, an air-through nonwoven fabric in which heat-bonding points between fibers are formed on a fiber web obtained by the card method or airlaid method, and a heat-bonding point between fibers is formed on a fiber web obtained by the card method by a heat roll method. Various nonwoven fabrics such as heat roll nonwoven fabric, heat embossed nonwoven fabric, spun lace nonwoven fabric, needle punched nonwoven fabric, and resin bonded nonwoven fabric can be used.

In particular, the nonwoven fabric, an apparent density of 0.005 g / cm ³ or more 0.5 g / cm ³ or less, is preferably used in particular 0.01 g / cm ³ or more 0.1 g / cm ³ or less is bulky nonwoven. By using a bulky non-woven fabric as the second sheet 6, the second sheet 6 functions as a spacer that separates the absorber 4 and the top sheet 2, and promotes air flow between the absorber 4 and the top sheet 2. . Also by this, the stuffiness in the wearing state of the panty liner 10 is further prevented. As the bulky nonwoven fabric, for example, an air-through nonwoven fabric, an airlaid nonwoven fabric, a resin bond nonwoven fabric, or the like can be suitably used.

  In addition, the width of the top sheet 2 and the second sheet 6 are reduced by making the width of the absorbent body 4 smaller than both the width of the top sheet 2 and the width of the second sheet 6 in at least the central region 10C in the longitudinal direction of the panty liner 10. Of the left and right side portions, the portion that extends outward in the width direction from the side edge 4a of the absorber 4 (see FIG. 2) can be easily maintained. As a result, even after the absorber 4 has absorbed the liquid, the water vapor permeability at the left and right sides of the panty liner 10 is less likely to be impaired. Therefore, the stuffiness in the wearing state is further reduced.

  In the panty liner 10 of this embodiment, the nonwoven fabric 1 used as the top sheet 2 is a fusion that forms a fiber sheet by thermally fusing the intersections of the constituent fibers of a fiber web containing high elongation fibers at the fusion part. It is suitably manufactured by a method for manufacturing a nonwoven fabric comprising a step and a stretching step of stretching the fiber sheet in one direction. One embodiment of the method for producing the nonwoven fabric 1 used as the top sheet 2 will be described with reference to FIG. FIG. 8 schematically shows a preferable manufacturing apparatus 100 used in the method for manufacturing the nonwoven fabric 1. The manufacturing apparatus 100 is suitably used for manufacturing an air-through nonwoven fabric. The manufacturing apparatus 100 includes a web forming unit 200, a hot air processing unit 300, an extending unit 400, and a lower sheet joining unit 500 in this order from the upstream side to the downstream side of the manufacturing process.

  As shown in FIG. 8, the web forming unit 200 includes a web forming apparatus 201. A card machine is used as the web forming apparatus 201. As a card machine, the thing normally used in the technical field of an absorbent article can be used without a restriction | limiting in particular. Instead of the card machine, other web manufacturing apparatuses such as airlaid apparatuses can be used.

  As shown in FIG. 8, the hot air processing unit 300 includes a hood 301. Inside the hood 301, hot air can be blown by an air-through method. The hot air processing unit 300 includes an endless conveyor belt 302 made of a breathable net. The conveyor belt 302 circulates in the hood 301. The conveyor belt 302 is made of a resin such as polyethylene terephthalate or a metal.

  The temperature of the hot air blown in the hood 301 and the heat treatment time are preferably adjusted so that the intersections of the high elongation fibers included in the constituent fibers 11 of the fiber web 1b are heat-sealed. More specifically, the temperature of the hot air is preferably adjusted to a temperature higher by 0 ° C. to 30 ° C. than the melting point of the resin having the lowest melting point among the constituent fibers 11 of the fiber web 1b. The heat treatment time is preferably adjusted to 1 to 5 seconds according to the temperature of the hot air. Further, from the viewpoint of promoting further entanglement between the constituent fibers 11, the wind speed of the hot air is preferably about 0.3 m / second to 1.5 m / second. Moreover, it is preferable that a conveyance speed is about 5 m / min-100 m / min.

  The extending | stretching part 400 is provided with a pair of uneven | corrugated roll 401,402 which can mutually mesh | engage as shown in FIG.8 and FIG.9. The pair of concave and convex rolls 401 and 402 are formed so as to be heatable, and are formed by alternately arranging large-diameter convex portions 403 and 404 and small-diameter concave portions (not shown) in the roll axis direction. The uneven rolls 401 and 402 may or may not be heated, but the heating temperature when heating the uneven rolls 401 and 402 makes it easy to stretch the high elongation fibers included in the constituent fibers 11 of the fiber sheet 1a described later. From the viewpoint, it is preferable to be not less than the glass transition point of the resin having the highest glass transition point in the high elongation fiber and not more than the melting point of the resin having the lowest melting point in the high elongation fiber. More preferably, the temperature is 10 ° C. higher than the glass transition point of the fiber and 10 ° C. lower than the melting point, more preferably 20 ° C. higher than the glass transition point of the fiber, and 20 ° C. lower than the melting point. is there. For example, when the core / sheath fiber is used as the fiber, PET (core) having a glass transition point of 67 ° C. and a melting point of 258 ° C./PE (sheath) having a glass transition point of −20 ° C. and a melting point of 135 ° C. is used. The temperature is preferably 67 ° C. or higher and 135 ° C. or lower, more preferably 77 ° C. or higher and 125 ° C. or lower, still more preferably 87 ° C. or higher and 115 ° C. or lower.

  In the manufacturing apparatus 100, as shown in FIG. 9, the interval (pitch) between the large-diameter convex portions 403, 403 adjacent to each other in the roll axis direction of the uneven roll 401 and the roll axis direction of the uneven roll 402 are adjacent to each other. The spacing (pitch) between the large-diameter convex portions 404 and 404 is the same spacing (pitch) w, and the spacing (pitch) w is such that the high elongation fibers included in the constituent fibers 11 of the fiber sheet 1a are successfully used in the stretching apparatus. From the viewpoint of stretching and extending the previously described small-diameter portion to the large-diameter portion adjacent to the fusion-bonded portion to improve the touch, it is preferably 1 mm or more and 10 mm or less, particularly preferably 1.5 mm or more. 8 mm or less. From the same viewpoint, as shown in FIG. 10, the pushing amount t of the pair of concave and convex rolls 401 and 402 (the distance between the vertex of the large-diameter convex portion 403 and the vertex of the large-diameter convex portion 404 adjacent to each other in the roll axis direction) is The thickness is preferably 1 mm or more and 3 mm or less, and particularly preferably 1.2 mm or more and 2.5 mm or less. From the same viewpoint, the mechanical stretch ratio is preferably 1.5 times or more and 3.0 times or less, and particularly preferably 1.7 times or more and 2.8 times or less.

  The lower sheet bonding portion 500 includes a concavo-convex roll 402 and a flat roll 501 having a smooth surface, and has a concavo-convex shape between the large-diameter convex portion 404 of the concavo-convex roll 402 and the peripheral surface of the flat roll 501. The nonwoven fabric 1 and the lower sheet 6 are joined by heating and pressing.

The manufacturing method of the nonwoven fabric 1 using the manufacturing apparatus 100 which has the above structure is demonstrated.
First, as shown in FIG. 8, in the web forming unit 200, a short fiber-shaped constituent fiber 11 having a heat-extensible composite fiber that is a high elongation fiber is used as a raw material, and a web forming apparatus 201 that is a card machine is used. A fiber web 1b is formed (web forming step). The fiber web 1b manufactured by the web forming apparatus 201 is in a state where its constituent fibers 11 are loosely entangled with each other, and has not yet achieved shape retention as a sheet.

  Next, as shown in FIG. 8, the fiber sheet 1 a is formed by thermally fusing the intersections of the constituent fibers 11 of the fiber web 1 b including the high elongation fibers at the fusion part 12 (fusing step). Specifically, the fiber web 1b is conveyed onto the conveyor belt 302, and hot air is blown in an air-through manner while passing through the hood 301 by the hot air processing unit 300. When hot air is thus blown by the air-through method, the constituent fibers 11 of the fiber web 10 are further entangled, and at the same time, the intersections of the entangled fibers are heat-sealed (see FIG. 10A), so that the sheet-like shape A fiber sheet 1a having shape retention is produced.

  Next, as shown in FIG. 8, the fused fiber web 1a is stretched in one direction (stretching step). Specifically, the fused fiber web 1a having a shape-retaining property as a sheet is conveyed between a pair of concavo-convex rolls 401 and 402, as shown in FIGS. 10 (a) to 10 (c). In addition, the fiber web 1a is stretched, and a large fiber diameter is sandwiched between two small-diameter portions 16 and 16 having a small fiber diameter in one constituent fiber 11 between adjacent fusion portions 12 and 12. The large diameter portion 17 is formed, and the change point 18 from the small diameter portion 16 to the large diameter portion 17 is set to be 1/3 of the interval T between the fusion portions 12 and 12 adjacent to the fusion portion 12. Form within the range. Specifically, as shown in FIG. 10A, the fiber sheet 1a in which the intersections of the constituent fibers 11 are thermally fused at the fusion part 12 is conveyed between a pair of concave and convex rolls 401 and 402. Then, the fiber web 1a is stretched in the orthogonal direction (CD, roll axis direction) orthogonal to the machine direction (MD, flow direction). When the fiber sheet 1a is stretched in the orthogonal direction (CD, roll axis direction), the adjacent fused portions 12, 12 fixing the constituent fibers 11 shown in FIG. Is actively stretched in the orthogonal direction (CD, roll axis direction). In particular, as shown in FIG. 10B, local contraction is likely to occur first in the vicinity of each fusion part 12 that fixes the constituent fibers 11, and 1 between adjacent fusion parts 12, 12. With respect to the constituent fiber 11, two small-diameter portions 16, 16 are formed at both ends, and a portion sandwiched between the two small-diameter portions 16, 16 becomes a large-diameter portion 17. A large-diameter portion 17 sandwiched between 16 is formed. In this way, local contraction is likely to occur first in the vicinity of each fusion part 12, so that the change point 18 from the small diameter part 16 to the large diameter part 17 is adjacent to the fusion part 12 adjacent to the fusion part 12. It is formed within a range of 1/3 of the interval T between the twelve.

  And about the one component fiber 11 between some adjacent fusion | melting parts 12 and 12, as shown in FIG.10 (c), in the state which left the room (extension margin) which can be extended | stretched, further It is stretched in the orthogonal direction (CD, roll axis direction), the large diameter portion 17 between the adjacent fused portions 12, 12 is stretched, and a plurality of small diameter portions 16 are formed in the large diameter portion 17. become.

  In the stretching step, the small diameter portion 16 and the large diameter portion 17 are formed from the high elongation fiber, and at the same time, the large diameter convex portion 403 of the concave / convex roll 401 and the large diameter convex portion of the concave / convex roll 402 in the fiber sheet 1a. A portion located between the portions 404 is extended more than other portions. In this case, since the constituent fiber of the fiber sheet 1a is a high elongation fiber, even if it is stretched, it is not cut and is successfully stretched. The part located between the large diameter convex part 403 of the uneven | corrugated roll 401 and the large diameter convex part 404 of the uneven | corrugated roll 402 among the fiber sheets 1a is the side area 13c of the protruding item | line part 13 in the target nonwoven fabric 1. FIG. Therefore, the fiber distance is not cut in the side region 13c by the above-described stretching, and the inter-fiber distance is increased as compared to before stretching. As a result, the fiber density of the side region 13c is lower than other parts, and air permeability is improved. And since the cut | disconnection has not arisen in the fiber which comprises the side part area | region 13c, the intensity | strength of the protruding item | line part 13 is maintained at a high level. As a result, even if a load is applied to the ridge 13, the ridge 13 is not easily crushed.

  The nonwoven fabric 1 manufactured as described above is conveyed to the sheet joining portion of the lower sheet joining portion 500 while being deformed into the uneven shape by the uneven roll 402. The sheet joining portion is supplied with the strip-shaped nonwoven fabric 6 for the second sheet unwound from the roll-shaped roll 6 ′, and the uneven nonwoven fabric 1 is in a state of being overlapped with the strip-shaped nonwoven fabric 6. Introduced between the uneven roll 402 and the flat roll 501. Between the concave-convex roll 402 and the flat roll 501, the concave strip portion and the strip-shaped nonwoven fabric 6 in the concave-convex nonwoven fabric 1 are between the large-diameter convex portion 404 of the concave-convex roll 402 and the peripheral surface of the flat roll 501. To be joined by being heated and pressurized. In this way, a band-shaped composite sheet 8 is obtained in which the topsheet 2 made of the nonwoven fabric 1 is joined to the lower sheet 6 at the concave strip portion 14. The belt-shaped composite sheet 8 is introduced into the production line of the panty liner 10 after being wound up, or is introduced into the production line of the panty liner 10 without being wound up.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, the absorbent article of this invention is not restrict | limited to this embodiment mentioned above at all, and can be changed suitably. For example, the above embodiment is an example in which the present invention is applied to the panty liner 10, but instead, the present invention is applied to other absorbent articles such as sanitary napkins, incontinence pads, and disposable diapers. Also good.

This invention discloses the following absorbent articles further regarding embodiment mentioned above.
<1>
A liquid permeable top sheet that forms a skin contact surface, a back sheet and an absorbent article interposed between both sheets, and an absorbent article having a longitudinal direction and a width direction,
The top sheet is composed of a nonwoven fabric having a concavo-convex structure in which strip-like ridges and recesses extending in the longitudinal direction are alternately arranged in the width direction, and is joined to the adjacent lower sheet in the recesses,
The nonwoven fabric is made from at least a high elongation fiber,
The lower sheet is made of an aggregate of thermoplastic resin fibers,
The ridge has a hollow structure between the nonwoven fabric and the lower sheet,
The non-woven fabric has a top region, a bottom region, and a side region located between the top region, the top portion of the protruding portion is formed from the top region, and the bottom portion of the recessed portion is formed from the bottom region. Formed,
The absorbent article in which the fiber density in the side region is lower than both the fiber density in the top region and the fiber density in the bottom region.

<2>
The absorbent article according to <1>, wherein the uneven structure has at least a central region in a width direction of the absorbent article.
<3>
The absorptivity according to <1> or <2>, wherein the convex portion can maintain the hollow structure in a state where a load of 4 g / cm ² is applied to the absorbent article from the surface sheet side. Goods.
<4>
The absorbent article according to any one of <1> to <3>, wherein the surface sheet and the lower sheet are joined intermittently along a direction in which the protruding portion extends.
<5>
In at least the longitudinal center region of the absorbent article, the width of the absorbent body is narrower than both the width of the top sheet and the width of the lower sheet,
At least in the central region in the longitudinal direction of the absorbent article, the absorbent body has a linear shape on each side edge, and is substantially parallel to the extending direction of the ridges and the ridges <1>. Thru | or <4> any one absorbent article.
<6>
The absorbent article has a shape in which each side edge is combined with a curve,
In the absorbent article, each side edge is curved convexly outward in the width direction in the front region and the rear region in the longitudinal direction, and each side edge is inward in the width direction in the central region in the longitudinal direction. The absorbent article according to any one of <1> to <5>, wherein the absorbent article is curved in a convex shape toward the center, whereby the width in the central region in the longitudinal direction is the narrowest.

<7>
The top sheet and the back sheet are joined at the periphery of the absorbent article,
The absorbent article according to any one of <1> to <6>, wherein the topsheet has the concavo-convex structure over the entire region inside the peripheral edge.
<8>
In any one of <1> to <7>, the convex portion can maintain the hollow structure in a state where a load of 20 g / cm ² is applied to the absorbent article from the surface sheet side. The absorbent article as described.
<9>
The absorbent article according to any one of <1> to <8>, wherein the absorbent body includes an absorbent sheet including a fiber material and a water-absorbing polymer.
<10>
The absorbent article according to <9>, wherein the absorbent body is a laminate in which the absorbent sheet is laminated in two or more layers.
<11>
The thickness of the absorber is preferably 0.1 mm or more, more preferably 0.5 mm or more, preferably 5 mm or less, more preferably 2 mm or less, and preferably 0.1 mm or more and 5 mm or less. The absorbent article according to any one of <1> to <10>, in which is 0.5 mm or more and 2 mm or less.

<12>
The lower sheet, an apparent density of 0.005 g / cm ³ or more 0.5 g / cm ³ or less, said to <1> not particularly made of 0.01 g / cm ³ or more 0.1 g / cm ³ or less is bulky nonwoven The absorbent article according to any one of <11>.
<13>
The absorbent article according to any one of <1> to <12>, wherein the nonwoven fabric includes fibers having a large diameter portion and a small diameter portion having different fiber diameters.
<14>
The absorbent article according to any one of <1> to <13>, wherein the nonwoven fabric includes a plurality of fused portions formed by heat-sealing intersections of constituent fibers.
<15>
The ratio (D _13c / D _13a , D _13c / D _13a ) of the fiber density D _{13c in} the side region to the fiber density D _13a in the top region or the fiber density D _13b in the bottom region is preferably 0. The absorbent article according to any one of <1> to <14>, which is from 15 to 0.9, more preferably from 0.2 to 0.8.
<16>
Fiber density _{D 13a} in the apex area is preferably 90 present / mm ² or more 200 present / mm ² or less, more preferably to the <1> to is 100 / mm ² or more 180 lines / mm ² or less <15 > Any one of>.

<17>
Fiber density _{D 13b} at the bottom area is preferably 80 present / mm ² or more 200 present / mm ² or less, more preferably to the <1> to be 180 lines / mm ² or less 90 present / mm ² or more <16 > Any one of>.
<18>
Fiber density _{D 13c} of the side region is preferably 30 present / mm ² or more eighty / mm ² or less, to further the <1> to preferably 40 present / mm ² or more 70 yarns / mm ² or less <17 > Any one of>.
<19>
The absorbent article according to any one of <1> to <18>, wherein the high elongation fiber is a core-sheath composite fiber having heat-fusibility.
<20>
Any of the above <1> to <19>, wherein the high elongation fiber has a fineness of preferably 1.0 dtex or more and 10.0 dtex or less, more preferably 2.0 dtex or more and 8.0 dtex or less at the raw material stage. Or an absorbent article according to claim 1.
<21>
The ratio of the high elongation fiber in the nonwoven fabric is preferably 50% by mass or more and 100% by mass or less, and more preferably 80% by mass or more and 100% by mass or less. The absorbent article as described.

<22>
When attention is paid to one constituent fiber among the constituent fibers of the nonwoven fabric, the constituent fiber has a large fiber diameter sandwiched between two small diameter portions having a small fiber diameter between adjacent fused portions. The absorbent article according to any one of <1> to <21>, wherein the absorbent article has a large diameter portion.
<23>
The absorbent article according to <22>, wherein when attention is paid to one of the constituent fibers, a plurality of the large-diameter portions are provided between the adjacent fused portions.
<24>
When focusing on one of the constituent fibers, the large-diameter portion is preferably provided with 1 or more and 5 or less, more preferably 1 or more and 3 or less between the adjacent fused portions. The absorbent article as described in <22> or <23>.
<25>
The ratio (L ₁₆ / L ₁₇ ) of the fiber diameter (diameter L ₁₆ ) of the small diameter portion 16 to the fiber diameter (diameter L ₁₇ ) of the large diameter portion is preferably 0.5 or more and 0.8 or less, more preferably 0. The absorbent article according to any one of <22> to <24>, which is from .55 to 0.7.
<26>
The fiber diameter (diameter L ₁₆ ) of the small diameter portion is preferably 5 μm or more and 28 μm or less, more preferably 6.5 μm or more and 20 μm or less, and particularly preferably 7.5 μm or more and 16 μm or less. The absorbent article of any one.

<27>
The fiber diameter (diameter L ₁₇ ) of the large diameter portion is preferably 10 μm or more and 35 μm or less, more preferably 13 μm or more and 25 μm or less, and particularly preferably 15 μm or more and 20 μm or less, any one of the above <22> to <26> Absorbent article as described in 1.
<28>
Paying attention to one constituent fiber, the change point from the small diameter part adjacent to the fusion part to the large diameter part is 1/3 of the interval T between the fusion parts adjacent to the fusion part. <22> thru | or <27> any one of the absorbent articles distribute | arranged in the range of these.
<29>
The non-woven fabric includes fibers having a large diameter portion and a small diameter portion having different fiber diameters,
The nonwoven fabric comprises the number of fibers having the change point in the constituent fibers constituting the side region, the number of fibers having the change point in the constituent fibers constituting the top region, and the bottom region. The absorbent article according to any one of <1> to <28>, wherein the constituent fibers are formed in a number larger than the number of fibers having the change point.
<30>
The side region with respect to the number of fibers having the change point (N _13a ) in the constituent fibers constituting the top region or the number of fibers having the change point (N _13b ) in the constituent fibers constituting the bottom region The ratio (N _13c / N _13a , N _13c / N _13b ) of the number (N _13c ) of fibers having the above-mentioned change point in the constituent fibers constituting the fiber is preferably 2 or more and 20 or less, more preferably 5 or more and 20 or less. The absorbent article as described in <29>.
<31>
The number (N _13a ) of fibers having the change point in the constituent fibers constituting the top region is preferably 1 or more and 15 or less, more preferably 5 or more and 15 or less. Absorbent article.

<32>
<30> or <31, wherein the number (N _13b ) of fibers having the change point in the constituent fibers constituting the bottom region is preferably 1 or more and 15 or less, more preferably 5 or more and 15 or less. The absorbent article as described in>.
<33>
<30> thru | or << which the number ( _{N13c) of the} fiber which has the said change point in the constituent fiber which comprises the said side part area | region is preferably 5 or more and 20 or less, More preferably, 10 or more and 20 or less. 32> The absorbent article of any one of 32.
<34>
Sheet thickness _{T S} of the nonwoven fabric is preferably 0.5mm or more 7mm or less, and more preferably wherein the 1.0mm or 5mm or less to <1> to absorbent article according to any one of <33>.
<35>
The layer thickness T _L1 of the top region of the nonwoven fabric is preferably 0.1 mm or more and 3.0 mm or less, and more preferably 0.2 mm or more and 2.0 mm or less. The absorbent article as described.
<36>
The layer thickness T _L2 of the bottom region of the nonwoven fabric is preferably 0.1 mm or more and 3.0 mm or less, and more preferably 0.2 mm or more and 2.0 mm or less. The absorbent article as described.

<37>
Any one of the above items <1> to <36>, wherein the layer thickness T _L3 of the side region of the nonwoven fabric is preferably 0.1 mm or more and 3.0 mm or less, more preferably 0.2 mm or more and 2.0 mm or less. Absorbent article as described in 1.
<38>
The non-woven fabric has an X direction that is a direction in which the ridges and the ridges extend, and a Y direction that is perpendicular to the X direction.
The absorptivity according to any one of <1> to <37>, wherein a pitch between the top portions of the protruding portions adjacent to each other in the Y direction is preferably 1 mm or more and 15 mm or less, and more preferably 1.5 mm or more and 10 mm or less. Goods.
<39>
The height of the protruding portion is preferably 0.5 mm or more and 5 mm or less, and more preferably 1 mm or more and 3 mm or less, the absorbent article according to any one of <1> to <38>.
<40>
The basis weight of the nonwoven fabric is preferably 15 g / ^{m 2} or more 50 g / ^{m 2} or less the average value of the entire, to 20 g / ^{m 2} or more 40 g / ^{m 2} or less and more preferably the <1> to any one of <39> 2. The absorbent article according to 1.
<41>
The <1> to <40> according to any one of <1> to <40>, wherein the lower sheet is a second sheet made of an aggregate of thermoplastic resin fibers disposed between the top sheet and the absorber. Absorbent article.

DESCRIPTION OF SYMBOLS 1 Nonwoven fabric 2 Top sheet 3 Back sheet 4 Absorbent body 10 Panty liner 11 Constituent fiber 12 Fusion part 13 Convex part 14 Concave part 14s Joining part 16 Small diameter part 17 Large diameter part 18 Change point 100 Manufacturing apparatus 200 Web formation part 201 Web Forming apparatus 300 Hot air processing unit 301 Hood 302 Conveyor belt 400 Stretching unit 401, 402 Concave roll 403, 404 Large diameter convex part

Claims (8)

A liquid permeable top sheet that forms a skin contact surface, a back sheet and an absorbent article interposed between both sheets, and an absorbent article having a longitudinal direction and a width direction,
The top sheet is composed of a nonwoven fabric having a concavo-convex structure in which strip-like ridges and recesses extending in the longitudinal direction are alternately arranged in the width direction, and is joined to the adjacent lower sheet in the recesses,
The nonwoven fabric is made from at least a high elongation fiber,
The lower sheet is made of an aggregate of thermoplastic resin fibers,
The ridge has a hollow structure between the nonwoven fabric and the lower sheet,
The non-woven fabric has a top region, a bottom region, and a side region located between the top region, the top portion of the convex portion is formed from the top region, and the bottom portion of the concave portion is formed from the bottom region. Has been
The absorbent article in which the fiber density in the side region is lower than both the fiber density in the top region and the fiber density in the bottom region.   The absorbent article of Claim 1 which has the said uneven structure at least in the center area of the width direction of the said absorbent article. The absorbent article according to claim 1 or 2, wherein the convex part can maintain the hollow structure in a state where a load of 4 g / cm ² is applied to the absorbent article from the surface sheet side.   The absorptive article according to any one of claims 1 to 3 with which joining of said surface sheet and said lower sheet is intermittently performed along the direction where said convex part extends. In at least the longitudinal center region of the absorbent article, the width of the absorbent body is narrower than both the width of the top sheet and the width of the lower sheet,
At least in the central region in the longitudinal direction of the absorbent article, each side edge of the absorbent body is linear, and is substantially parallel to the extending direction of the ridges and the ridges. The absorbent article as described in any one of 4. The absorbent article has a shape in which each side edge is combined with a curve,
In the absorbent article, each side edge is curved convexly outward in the width direction in the front region and the rear region in the longitudinal direction, and each side edge is inward in the width direction in the central region in the longitudinal direction. The absorbent article according to any one of claims 1 to 5, wherein the absorbent article is curved in a convex shape toward the center, whereby the width in the central region in the longitudinal direction is the narrowest. The top sheet and the back sheet are joined at the periphery of the absorbent article,
The absorptive article according to any one of claims 1 to 6 in which said surface sheet has said concavo-convex structure in the whole region inside the peripheral part. The said convex part can maintain the hollow structure in the state which added the load of 20 g / cm < ² > from the surface sheet side to the said absorbent article, The Claim 1 thru | or 7 any one. Absorbent article.

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