JP2019042400A - Absorbent article - Google Patents

Abstract

To provide an absorbent article which is excellent in shape retention of an absorber during it is worn, is improved in liquid diffusion properties, and is improved in utilization efficiency of the absorber.SOLUTION: An absorbent article 1 comprises an absorbent core 40, and a core wrap sheet 41 coating the absorbent core 40. The absorbent core 40 has a non-fiber-stacked part 48 penetrating in the thickness direction. The core wrap sheet 41 has a skin side core wrap sheet 41U and a non-skin side core wrap sheet 41D. The skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D are laminated sheets which have a hydrophilic fiber layer 43 arranged at an inner surface side, and having a non-thermoplastic hydrophilic fiber 45 as the main body, and a synthetic fiber layer 42 arranged at an outer surface side, and having a thermoplastic synthetic fiber 44 as the main body. The skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D are integrated via a consolidation part 46 in the non-fiber-stacked part 48 of the absorbent core 40.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an absorbent article such as a disposable diaper.

  As absorbent articles such as disposable diapers, a liquid-permeable surface sheet that forms a skin-facing surface, a liquid-impermeable back sheet that forms a non-skin-facing surface, and an absorption disposed between both sheets It is known that the absorbent body includes an absorbent core including an absorbent material such as wood pulp or a water-absorbing polymer, and a core wrap sheet that covers the outer surface of the absorbent core.

  The core wrap sheet serves as a sheet for receiving the absorbent material during the production of the absorbent body, and plays a role of wrapping the absorbent core and shaping it after the production. As the core wrap sheet, it is common to use a water-permeable sheet such as thin paper or absorbent paper. From the viewpoint of improving the strength of the absorbent after absorbing body fluid, the applicant first It was proposed to use a conductive sheet (Patent Documents 1 and 2).

  In Patent Document 1, a non-stacked fiber portion is provided in a liquid-retaining absorbent core, and the skin-side core wrap sheet covering the absorbent core and the non-skin-side core wrap sheet are bonded to each other in the non-stacked fiber portion. An absorbent article comprising an absorbent body is described. Patent Document 1 describes the use of a hydrophilic nonwoven fabric made of fibers subjected to hydrophilic treatment as a core wrap sheet.

  Patent Document 2 describes that the core wrap sheet covering the absorbent core has a two-layer structure including a first layer made of nonwoven fabric and a second layer made of nonwoven fabric, which have different liquid permeation speeds. Yes.

Japanese Patent Laying-Open No. 2006-83194 JP 2013-180171 A

  According to the absorbent article described in Patent Document 1, the shape of the absorbent body is excellent, the absorbent body is not easily broken during wearing, and the feeling of use is improved. Moreover, according to the absorbent article of patent document 2, liquid permeability and liquid diffusibility improve, and the utilization efficiency of an absorber improves. However, there was a need to improve the shape retention of the absorbent body during wearing, further improve the liquid diffusibility, and further improve the utilization efficiency of the absorbent body. Patent Document 1 does not describe anything about using a multilayer nonwoven fabric for the core wrap sheet. Moreover, although patent document 2 describes using a nonwoven fabric of a multilayer structure for a core wrap sheet, there was room for improvement about the fiber which comprises each layer.

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

The present invention comprises an absorbent body having a liquid-retaining absorbent core and a core wrap sheet that covers the absorbent core, and a longitudinal direction extending from the wearer's abdomen to the back through the crotch and the longitudinal direction. And an absorptive article comprising a crotch part arranged in the crotch part and a ventral part and a dorsal part extending in front and rear thereof, wherein the absorbent core has a thickness direction. The core wrap sheet has a skin-side core wrap sheet that covers the skin facing surface of the absorbent core, and a non-skin side that covers the non-skin facing surface of the absorbent core Each of the skin-side core wrap sheet and the non-skin-side core wrap sheet is arranged on the inner surface side in contact with the absorbent core and is mainly composed of non-thermoplastic hydrophilic fibers. The hydrophilic fiber layer and the contact with the hydrophilic fiber layer A laminated sheet having a synthetic fiber layer mainly composed of a thermoplastic synthetic fiber, and the skin-side core wrap sheet and the non-stacked portion of the absorbent core. It is an absorbent article in which the skin-side core wrap sheet is integrated with each other via a compacted portion.

  ADVANTAGE OF THE INVENTION According to this invention, the absorbent article which is excellent in the shape retention property of the absorber in wear, improves liquid diffusibility further, and further improves the utilization efficiency of an absorber is provided.

FIG. 1 is a plan view schematically showing a skin facing surface, that is, a surface sheet side of an unfoldable disposable diaper that is an embodiment of the absorbent article of the present invention. The elastic member of each part is stretched and expanded in a planar shape. FIG. 2 is a cross-sectional view schematically showing a cross section taken along line II-II in FIG. FIG. 3 is a plan view of an absorber provided in the disposable diaper shown in FIG. 1. 4 is a cross-sectional view schematically showing a cross section taken along line IV-IV in FIG. FIG. 5 is a cross-sectional view schematically showing a cross section along the thickness direction of the compacted portion in the absorbent body provided in the disposable diaper shown in FIG. 1. FIG. 6A and FIG. 6B are plan views schematically showing other patterns of the consolidated portion in the absorbent body according to the present invention.

  Hereinafter, an absorptive article of the present invention is explained with reference to drawings based on an example of a deployment type disposable diaper which is the preferred embodiment. 1 and 2 show a deployable disposable diaper 1 of the present embodiment. The diaper 1 includes an absorbent body 4 having a liquid-retaining absorbent core 40 and a core wrap sheet 41 that covers the absorbent core 40. The diaper 1 includes a vertical direction X extending from the wearer's stomach side to the back side through the crotch portion and a lateral direction Y orthogonal thereto, and extends to the crotch portion 1M disposed in the crotch portion and to the front and rear thereof. It has a ventral side 1F and a dorsal side 1R. The abdominal side portion 1F, the crotch portion 1M, and the back side portion 1R correspond to respective regions when the diaper 1 is divided into three equal parts in the vertical direction X. The crotch part 1M has an excretion part facing part that is disposed to face an excretion part such as a wearer's penis and anus when the diaper 1 is worn, and the excretion part facing part is usually in the longitudinal direction X of the diaper 1. Located at or near the center. In the following description, the thickness direction, which is a vertical direction orthogonal to the surface direction composed of the vertical direction X and the horizontal direction Y, is defined as the Z direction.

  As shown in FIGS. 1 and 2, the diaper 1 is disposed on the skin facing surface side of the absorbent body 4 having the absorbent core 40 and the absorbent body 4, and is located closer to the wearer's skin than the absorbent body 4. The liquid-permeable surface sheet 2 that can come into contact with the wearer's skin when worn and the non-skin-facing surface side of the absorbent body 4 is located farther from the wearer's skin than the absorbent body 4. A permeable or water-repellent back sheet 3 is provided. In a plan view as shown in FIG. 1, the diaper 1 has a vertically long hourglass shape in which a central portion in the longitudinal direction X located in the crotch portion 1M is bound inward and is long in one direction, that is, the longitudinal direction X. The top sheet 2 and the back sheet 3 have dimensions larger than the absorbent body 4 interposed between the sheets 2 and 3, respectively, and form the outer shape of the unfolded and stretched diaper 1 as shown in FIG. ing.

In the present specification, the “skin facing surface” refers to a surface of the absorbent article or a component thereof (for example, the absorbent core 40) that is directed toward the wearer's skin when the absorbent article is worn, that is, relatively. It is the side close to the skin of the wearer, and the “non-skin facing surface” is the surface of the absorbent article or its constituent members that is directed to the side opposite to the skin side (clothing side) when the absorbent article is worn, that is, relative It is the side far from the wearer's skin. Here, “when worn” means a state in which a normal proper wearing position is maintained.

  Between the top sheet 2 and the back sheet 3 at the waist of each of the ventral part 1F and the dorsal part 1R, that is, at the end in the longitudinal direction X, a belt-like elastic member 11 is abbreviated in the transverse direction Y of the diaper 1. It is fixed in a stretched state in the lateral direction Y over the entire length, whereby a waist gather is formed in the waist portion when the diaper 1 is worn by contraction of the elastic member 11. In addition, a plurality of thread-like elastic members 12 are fixed in the lateral direction Y in a stretched state between the top sheet 2 and the back sheet 3 in the waist part corresponding to the waist of the wearer in the back side part 1R. Thus, around the waist when the diaper 1 is worn, a waist circumference gather is formed by the contraction of the elastic member 12. Moreover, the side seat | sheet 5 is distribute | arranged to the left-right both sides along the vertical direction X in the surface sheet 2 side of the diaper 1, ie, the skin opposing surface side, respectively. The side seat 5 has an inner edge along the vertical direction X, and an outer edge along the vertical direction X that is located outside the inner edge in the lateral direction Y, and has a flat surface as shown in FIG. In view, the inner edge overlaps with the absorber 4, and the outer edge extends outward from the side edge along the longitudinal direction X of the absorber 4 in the lateral direction Y, as shown in FIG. 3 is joined. Between the side sheet 5 and the back sheet 3 in the left and right leg portions arranged around the legs of the wearer, a thread-like elastic member 13 is fixed in an extended state along the vertical direction X. A pair of leg gathers is formed by contraction of the elastic member 13 in the leg portion when the diaper 1 is worn. In addition, a thread-like elastic member 14 is fixed to the inner edge of the side seat 5 in an elongated state along the longitudinal direction X, and the inner edge is at least a crotch 1M, specifically, for example, In the crotch part 1M and the part near the crotch part 1M in the abdomen side part 1F and the dorsal side part 1R, the other constituent members of the diaper 1 including the topsheet 2 are non-joined free end parts. The front and rear end portions in the longitudinal direction X of 1F and the back side portion 1R are joined to the topsheet 2 (not shown). With such a configuration of the side seat 5, when the diaper 1 is worn, the contraction force of the elastic member 14 acts in the longitudinal direction X, and the side seat 5 has a crotch portion 1 </ b> M that is a region where at least an inner edge is a free end. In this case, the pair of right and left leak-proof cuffs are formed standing up toward the wearer's skin starting from the joint with the back sheet 3. The top sheet 2, the back sheet 3, the absorber 4, the side sheet 5, and the elastic members 11 to 14 are joined to each other by a known joining means such as a hot melt adhesive.

  As shown in FIG. 1, a pair of fastening tapes 6, 6 are provided on both side edges along the longitudinal direction X of the back side 1 </ b> R of the diaper 1. A fastening portion 61 made of a male member of a mechanical surface fastener is attached to the fastening tape 6. Moreover, the to-be-attached area | region 7 which consists of a female member of a mechanical hook-and-loop fastener is formed in the non-skin opposing surface of the belly side part 1F of the diaper 1. FIG. The to-be-attached region 7 is formed by attaching a female member of a mechanical hook-and-loop fastener to the non-skin facing surface of the back sheet 3 that forms the non-skin facing surface of the abdominal side portion 1F by a known joining means such as adhesive or heat seal The fastening part 61 of the fastening tape 6 can be detachably fastened.

As the top sheet 2, it is possible to use various types of conventionally used absorbent articles such as disposable diapers without any particular limitation, and it is assumed that the top sheet 2 is a liquid-permeable sheet that can permeate body fluids such as urine and feces. As a woven fabric, a nonwoven fabric, a porous sheet, etc. which consist of synthetic fiber or a natural fiber, it can be used. As an example of the surface sheet 2, a non-woven fabric made of natural fibers such as cotton or a non-woven fabric made of various synthetic fibers subjected to hydrophilic treatment can be used. For example, a core-sheath structure type (including side-by-side type) composite fiber using polypropylene or polyester as the core component and polyethylene as the sheath component is made into a web by carding, and then nonwoven fabric (after this is opened at a predetermined location) by the air-through method That may be treated). From the viewpoint of high liquid permeability (dry feeling), an apertured sheet made of polyolefin such as low density polyethylene can also be preferably used.
As the back sheet 3, various materials conventionally used for absorbent articles such as disposable diapers can be used without particular limitation, and liquid-impermeable (including water repellency) and moisture-permeable materials are preferable. Used. Specifically, in order to obtain sufficient water vapor permeability, a porous film having a fine hole formed by stretching a film made of a synthetic resin such as polyethylene in which fine powder made of a filler such as calcium carbonate is dispersed is a back sheet. 3 can be suitably used.
As the side sheet 5, what can be used as the back surface sheet 3 can be used.

  As shown in FIGS. 2 and 3, the absorbent body 4 includes a liquid-retaining absorbent core 40 and a core wrap sheet 41 that covers the absorbent core 40. The absorbent core 40 and the core wrap sheet 41 are joined by a known joining means such as a hot melt adhesive except for a non-stacking portion 48 described later. The absorbent core 40 constituting the absorbent body 4 has an hourglass shape in which the central portion of the longitudinal direction X located at the crotch 1M is inwardly bound in the longitudinal direction X in plan view as shown in FIGS. It has a long vertical shape.

  The absorbent core 40 is mainly composed of an absorbent material, and the content of the absorbent material in the absorbent core 40 is usually about 100% by mass. As an absorptive material, various things conventionally used for absorbent articles, such as a disposable diaper, can be used without a restriction | limiting in particular, For example, the synthetic fiber processed with the cellulosic fiber, such as a wood pulp, and a hydrophilizing agent And other hydrophilic fibers and water-absorbing polymers. Examples of the structure of the absorbent core 40 include a structure in which a hydrophilic fiber stack, a structure in which a water-absorbing polymer is supported on the stack, or a structure made of only a water-absorbing polymer.

  The absorptive core 40 has a non-stacking portion 48 that penetrates in the thickness direction Z. The non-stacking portion 48 is preferably disposed at least in the crotch portion 1M. In the diaper 1, the entire region of the crotch portion 1M is included from the crotch portion 1M to the ventral side portion 1F in a plan view as shown in FIG. It extends in the longitudinal direction X over a part and over a part of the back side part 1R from the crotch part 1M. Here, the fact that the non-stacked fiber part 48 is arranged at least in the crotch part 1M means that the non-stacked fiber part 48 extending in the longitudinal direction X is applied to the crotch part 1M even a little. Moreover, it is preferable that the non-stacked fiber portion 48 does not contain any absorbent material that forms the absorbent core 40. In the diaper 1, as shown in FIG.1 and FIG.2, the two non-stacking parts 48 are distribute | arranged. Each of the pair of non-stacking portions 48 and 48 includes the entire crotch portion 1 </ b> M and extends in a strip shape in parallel to the longitudinal direction X.

The basis weight of the absorbent core 40 excluding the non-stacked fiber portion 48 is preferably 50 g / m ² or more and 550 g / m ² or less from the viewpoint of suppressing discomfort when wearing the diaper 1 and improving fit. 100 g / m ² or more and 500 g / m ² or less is more preferable.
From the same viewpoint, the area of the non-stacked fiber part 48 (the total area of the two non-stacked fiber parts 48 in the diaper 1) (S1) is preferably 5 cm ² or more, and more preferably 10 cm ² or more. Preferably, it is preferably 60 cm ² or less, more preferably 50 cm ² or less, specifically preferably 5 cm ² or more and 60 cm ² or less, more preferably 10 cm ² or more and 50 cm ² or less. . Here, the area of each non-stacked fiber portion 48 means the area of the portion surrounded by the outline of the non-stacked fiber portion 48 in plan view of the absorbent core 40.

In the diaper 1, the absorbent core 40 is viewed in plan as shown in FIG. 3, and the ratio of the area (S1) of the non-stacked fiber portion 48 to the area (surface area) (S0) of the absorbent core 40 ((S1 / S0) × 100) suppresses the uncomfortable feeling when the diaper 1 is worn, improves fit, facilitates diffusion of body fluids in the vertical direction X, improves the smoothness, and improves the utilization efficiency of the absorbent body 4 From the viewpoint of improving suppression of leakage of body fluid due to improvement, it is preferably 2% or more, more preferably 4% or more, preferably 25% or less, more preferably 20% or less, Specifically, it is preferably 2% or more and 25% or less, and more preferably 4% or more and 20% or less. Here, the area (surface area) (S0) of the absorbent core 40 refers to the area of the entire absorbent core 40 when the absorbent core 40 is viewed in plan, and the non-stacked fiber portion included in the absorbent core 40 It shall include 48 areas (S1).

  As shown in FIGS. 2 to 4, the core wrap sheet 41 includes a skin-side core wrap sheet 41 </ b> U that covers the skin facing surface of the absorbent core 40 and a non-skin side that covers the non-skin facing surface of the absorbent core 40. A core wrap sheet 41D. The skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D may be formed of different sheets, but the diaper 1 is formed of one core wrap sheet 41. Specifically, one core wrap sheet 41 is longer than the length of the absorbent core 40 in the longitudinal direction X in the longitudinal direction X, and as shown in FIG. 2 in the lateral direction Y. The skin facing surface of the absorbent core 40 is covered, and further, both side portions along the longitudinal direction X of the core wrap sheet 41 are wound on the non-skin facing surface side of the absorbent core 40, The absorbent core 40 is wrapped so as to overlap at the center Y in the lateral direction of the opposing surface. Thus, in one core wrap sheet 41 enclosing the absorbent core 40, the sheet portion covering the skin facing surface of the absorbent core 40 becomes the skin side core wrap sheet 41U, and the non-skin facing surface of the absorbent core 40 The sheet | seat part which coat | covers becomes non-skin side core wrap sheet | seat 41D.

  As shown in FIG. 4, each of the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D is arranged on the inner surface side in contact with the absorbent core 40 and mainly includes non-thermoplastic hydrophilic fibers 45. The laminated sheet has a hydrophilic fiber layer 43 and a synthetic fiber layer 42 that is arranged on the outer surface side in contact with the hydrophilic fiber layer 43 and is mainly composed of a thermoplastic synthetic fiber 44. An absorbent core 40, a skin-side core wrap sheet 41U disposed on the skin facing surface side of the absorbent core 40, and a non-skin side core wrap sheet 41D disposed on the non-skin facing surface side of the absorbent core 40 A cross section along the thickness direction (Z direction) is shown.

  The synthetic fiber layer 42 is mainly composed of thermoplastic synthetic fibers 44, and the hydrophilic fiber layer 43 is mainly composed of non-thermoplastic hydrophilic fibers 45. The synthetic fiber layer 42 contains at least 40% by mass of the thermoplastic synthetic fiber 44, and the content of the thermoplastic synthetic fiber 44 may be 100% by mass with respect to the total mass of the synthetic fiber layer 42. The hydrophilic fiber layer 43 contains at least 50 mass% of non-thermoplastic hydrophilic fibers 45, and the content of the non-thermoplastic hydrophilic fibers 45 is 100 with respect to the total mass of the hydrophilic fiber layer 43. It may be mass%.

  As shown in FIG. 4, the skin-side core wrap sheet 41 </ b> U is relatively close to the skin of the wearer, relatively to the synthetic fiber layer 42 disposed on the outer surface side of the absorbent core 40, and relatively to the wearer's skin. It is configured to include a laminated structure (two-layer structure) with the hydrophilic fiber layer 43 on the inner surface side that contacts the absorbent core 40 far away. The synthetic fiber layer 42 of the skin-side core wrap sheet 41 </ b> U is disposed to face the top sheet 2, and the hydrophilic fiber layer 43 is disposed to face the absorbent core 40. The synthetic fiber layer 42 and the hydrophilic fiber layer 43 are integrated with each other through at least a compaction portion 46 to be described later. Depending on the manufacturing method, the constituent fibers of both layers 42 and 43 may be entangled with each other, adhesive, and the like. It can also be integrated by other integration means such as joining means.

As shown in FIG. 4, the non-skin-side core wrap sheet 41 </ b> D is relatively distant from the wearer's skin and is relatively distant from the wearer's skin and the synthetic fiber layer 42 disposed on the outer surface side of the absorbent core 40. It is comprised including the laminated structure (two-layer structure) with the hydrophilic fiber layer 43 of the inner surface side contact | abutted to the absorptive core 40 near. The synthetic fiber layer 42 of the non-skin side core wrap sheet 41 </ b> D is disposed to face the back sheet 3, and the hydrophilic fiber layer 43 is disposed to face the absorbent core 40. The synthetic fiber layer 42 and the hydrophilic fiber layer 43 are integrated with each other through at least a compaction portion 46 to be described later. Depending on the manufacturing method, the constituent fibers of both layers 42 and 43 may be entangled with each other, adhesive, and the like. It can also be integrated by other integration means such as joining means.

  In the core wrap sheet 41 of the diaper 1, both the synthetic fiber layer 42 and the hydrophilic fiber layer 43 are fiber assemblies. The form of such a fiber assembly is not particularly limited, and examples thereof include nonwoven fabric, woven fabric, and paper. In a typical form, the synthetic fiber layer 42 is a nonwoven fabric and the hydrophilic fiber layer 43 is paper. 4 and 5, from the viewpoint of facilitating understanding, the thermoplastic synthetic fibers 44 are indicated by relatively thin lines and the non-thermoplastic hydrophilic fibers 45 are indicated by relatively thick lines. It is independent of the actual fiber thickness.

  The skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are each configured to include a nonwoven fabric that constitutes the synthetic fiber layer 42. As the nonwoven fabric constituting the synthetic fiber layer 42, those produced by various production methods can be used without particular limitation. Examples thereof include a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunbond-meltblown-spunbond nonwoven fabric, and an air-through nonwoven fabric. Spunlace nonwoven fabric, resin bond nonwoven fabric, needle punched nonwoven fabric, and the like. A laminate obtained by combining two or more of these nonwoven fabrics, or a laminate obtained by combining these nonwoven fabrics and a film can also be used. Among these nonwoven fabrics, the spunbond nonwoven fabric and the spunbond-meltblown-spunbond nonwoven fabric have an effect of preventing leakage of an absorbent material such as a water-absorbing polymer contained in the absorbent core 40 as compared with an air-through nonwoven fabric. It is preferable because it is excellent. From the same viewpoint, the average interfiber distance of the spunbond nonwoven fabric or the spunbond-meltblown-spunbond (SMS) nonwoven fabric is preferably 10 μm or more, more preferably 20 μm or more, and preferably 200 μm or less, more preferably 180 μm. It is as follows. The average interfiber distance is measured by the following method. The average interfiber distance is measured at a portion other than the consolidated portion 46.

<Measuring method of the average interfiber distance of the nonwoven fabric which comprises the synthetic fiber layer 42>
The average interfiber distance of a fiber assembly such as a nonwoven fabric or paper is obtained by the following formula (1) based on the assumption of Wrotnowski. The following formula (1) is generally used when determining the inter-fiber distance of the fiber assembly. Under the Wrotnowski assumption, the fibers are cylindrical, and the fibers are regularly arranged without crossing.
When the sheet to be measured (skin-side core wrap sheet 41U or non-skin-side core wrap sheet 41D) has a single-layer structure, the average inter-fiber distance of the sheet having the single-layer structure is obtained by the following formula (1).
When the sheet to be measured has a multilayer structure such as an SMS nonwoven fabric, the average inter-fiber distance of the sheet having the multilayer structure is determined according to the following procedure.
First, the average inter-fiber distance of each layer constituting the multilayer structure is calculated by the following formula (1). At that time, the thickness t, the basis weight W, the fiber density ρ, and the fiber diameter D used in the following formula (1) are respectively those for the measurement target layer, and the thickness t is the thickness direction of the measurement target layer. Measured by microscopic observation of a cross section along the line. The thickness t, the basis weight W, and the fiber diameter D are average values of measured values at a plurality of measurement points, respectively. The basis weight W (g / m ² ) is obtained by cutting a sheet to be measured into a predetermined size and dividing the weight measurement value by an area obtained from the predetermined size after the weight measurement. The fiber density ρ (g / cm ³ ) is measured according to JIS using a density gradient tube.
Measured according to the density gradient tube method described in L1015 Chemical Fiber Staple Test Method (URL is http://kikakuru.com/l/L1015-2010-01.html, JIS Handbook Fiber-2000 for books) (Described in P.764-765 of Japanese Standards Association). The fiber diameter D (μm) is measured using a scanning electron microscope (DSC6200, manufactured by Seiko Instruments Inc.), 10 fiber cross sections of the cut fibers, and the average value is taken as the fiber diameter.
Next, by multiplying the average inter-fiber distance of each layer by the ratio of the thickness of the layer to the total thickness of the multilayer structure, and further adding up the numerical values for each layer thus obtained, the target multilayer structure The average interfiber distance of the constituent fibers of the sheet is obtained. For example, in an SMS nonwoven fabric having a three-layer structure composed of two S layers and one M layer, the two S layers are treated as one layer and the total thickness t of the three-layer structure is 0.11 mm, This is the case when the thickness t of the S layer is 0.1 mm, the average inter-fiber distance LS of the S layer is 47.8 μm, the thickness t of the M layer is 0.01 mm, and the average inter-fiber distance LS of the M layer is 3.2 μm. The average interfiber distance of the constituent fibers of the SMS nonwoven fabric is 43.8 μm [= (47.9 × 0.1 + 3.2 × 0.01) /0.11].

  The preferable skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D include a synthetic fiber layer 42 made of a spunbond nonwoven fabric or an SMS nonwoven fabric having an average interfiber distance within the above range, and this synthetic fiber layer The thermoplastic synthetic fiber 44, which is the main constituent fiber of 42, and a non-thermoplastic hydrophilic fiber 45 such as wood pulp are intertwined. If the average inter-fiber distance of the synthetic fiber layer 42 is too large, the effect of preventing leakage of the absorbent material from the absorbent core 40 by the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D is reduced. When a water-absorbing polymer having a small particle size is used as the absorbent material, the particles may leak out.

The reason why the spunbond nonwoven fabric or the SMS nonwoven fabric is adopted as the synthetic fiber layer 42 of the skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D is to achieve both the strength suitable for the core wrap sheet and the interfiber distance, and the absorption performance. This is to make the liquid return difficult to occur. Examples of the thermoplastic synthetic fiber 44 that is the main constituent fiber of these nonwoven fabrics include synthetic fibers (for example, polypropylene fibers) that have not been subjected to hydrophilic treatment. The basis weight of the synthetic fiber layer 42 of each of the skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D is preferably 0.1 g / m ² or more, more preferably 0.3 g / m ² or more, and preferably It is 10 g / m ² or less, more preferably 8 g / m ² or less.

  As the thermoplastic resin that is a material of the thermoplastic synthetic fiber 44, those usually used for constituent fibers such as a nonwoven fabric can be used without particular limitation. For example, polyethylene, polypropylene, polybutene-1, polypentene-1, And polyolefins such as random or block copolymers thereof; polyesters such as polyethylene terephthalate and polybutylene terephthalate; polyamides such as nylon-6 and nylon-66. The thermoplastic synthetic fiber 44 may be a single fiber formed using a single thermoplastic resin or a composite fiber formed using two or more kinds of thermoplastic resins. Examples of the composite fiber include a core-sheath fiber, a side-by-side fiber, a split fiber, an alternating array fiber, and a sea-island fiber. The synthetic fiber layer 42 may contain two or more types of thermoplastic synthetic fibers 44. Among these, polyethylene and polypropylene are preferably used as the thermoplastic synthetic fiber 44 because they are inexpensive and have a relatively low melting point.

The skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are used as absorbent articles as the non-thermoplastic hydrophilic fibers 45 constituting the hydrophilic fiber layer 43 on the premise that they do not have thermoplasticity. Various hydrophilic fibers conventionally used can be used without particular limitation, and a typical one is cellulose fiber. Examples of the cellulose fiber include natural cellulose fibers such as wood pulp such as softwood kraft pulp and hardwood kraft pulp, and non-wood pulp such as cotton pulp and straw pulp; and regenerated cellulose fibers such as rayon and cupra. Can be used alone or in admixture of two or more.
Among these, wood pulp is most preferable from the viewpoint that the fiber length is shorter than that of regenerated cellulose or non-wood pulp, so that it is likely to be exposed to the surface through the gap between the thermoplastic synthetic fibers 44 constituting the synthetic fiber layer 42. Used.

  In the diaper 1, in each of the skin-side core wrap sheet 41 </ b> U and the non-skin-side core wrap sheet 41 </ b> D, the body sheet once absorbed by the absorbent core 40 is a surface sheet with a synthetic fiber layer 42 disposed on the outer surface side of the absorbent core 40. From the viewpoint of preventing return to the second side, the thermoplastic synthetic fiber 44 constituting the synthetic fiber layer 42 has a hydrophilicity that is greater than the hydrophilicity of the non-thermoplastic hydrophilic fiber 45 constituting the hydrophilic fiber layer 43. Is preferably low. Further, from the viewpoint of improving the utilization efficiency of the absorbent core 40 by diffusing body fluid with the hydrophilic fiber layer 43 disposed to face the absorbent core 40, the non-thermoplastic hydrophilic fiber 45 constituting the hydrophilic fiber layer 43. The hydrophilicity of the thermoplastic synthetic fiber 44 constituting the synthetic fiber layer 42 is preferably higher than that of the thermoplastic synthetic fiber 44.

  In the present invention, the hydrophilicity of the fiber is determined based on the contact angle with water measured by the following method. If the contact angle is less than 90 degrees, the fiber is hydrophilic, and if the contact angle is 90 degrees or more, the fiber is hydrophobic. is there. The smaller the contact angle with water measured by the following method, the higher the hydrophilicity (lower hydrophobicity), and the higher the contact angle, the lower the hydrophilicity (highly hydrophobic). In the core wrap sheet 41, the contact angle with water of the non-thermoplastic hydrophilic fiber 45 forming the main body of the hydrophilic fiber layer 43 is less than 90 degrees, and the thermoplastic synthetic fiber 44 forming the main body of the synthetic fiber layer 42 The contact angle with water is preferably 90 degrees or more.

<Measurement method of contact angle>
A fiber is taken out from the measurement target (skin-side core wrap sheet 41U or non-skin-side core wrap sheet 41D), and the contact angle of water with the fiber is measured. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Distilled water is used to measure the contact angle. The amount of liquid discharged from an ink jet type water droplet discharge part (manufactured by Cluster Technology, Inc., pulse injector CTC-25 having a discharge part pore diameter of 25 μm) is set to 20 picoliters, and a water drop is dropped directly above the fiber. The state of dripping is recorded on a high-speed recording device connected to a horizontally installed camera. The recording device is preferably a personal computer incorporating a high-speed capture device from the viewpoint of image analysis later. In this measurement, an image is recorded every 17 msec. In the recorded video, the first image of water droplets on the fiber is attached to the attached software FAMAS (software version is 2.6.2, analysis method is droplet method, analysis method is θ / 2 method, image processing algorithm Is non-reflective, the image processing image mode is frame, the threshold level is 200, and the curvature is not corrected)), and the angle between the surface of the water droplet that touches the air and the fiber is calculated and contacted. A corner. The fiber taken out from the object to be measured is cut into a fiber length of 1 mm, and the fiber is placed on a sample table of a contact angle meter and kept horizontal. Two different contact angles are measured per fiber. N = 5 contact angles are measured to one decimal place, and a total of 10 measured values (rounded to the second decimal place) is defined as the contact angle of the fiber with water. The measurement environment is a room temperature of 22 ± 2 ° C. and a humidity of 65 ± 2% RH.

  In the case where the constituent member (for example, the core wrap sheet 41) is taken out from the absorbent article and evaluated and measured, when the constituent member is fixed to another constituent member by adhesive, fusion, etc., The fixed portion is removed after being removed by applying a solvent, spraying hot air with a dryer, or spraying a cold spray (for example, a commercial product manufactured by Nichiban Co., Ltd.).

In the non-stacking portion 48 of the absorbent core 40, as shown in FIGS. 4 and 5, the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are integrated with each other via the compaction portion 46. Yes. The consolidated portion 46 is a thermoplastic synthetic fiber 44 constituting the skin side core wrap sheet 41U.
And the thermoplastic synthetic fiber 44 which comprises the non-skin side core wrap sheet | seat 41D may be fuse | melted and formed integrally, and it may be crimped | bonded by pressure without applying heat and may be integrally formed. In the diaper 1, the compacted portion 46 is integrally formed by melting the thermoplastic synthetic fiber 44 constituting the skin-side core wrap sheet 41U and the thermoplastic synthetic fiber 44 constituting the non-skin-side core wrap sheet 41D. ing. Thus, in the diaper 1, the synthetic fiber layer 42 and the hydrophilic fiber layer 43 of the skin-side core wrap sheet 41 </ b> U and the non-skin-side core wrap sheet 41 </ b> D in the compacted portion 46 of the non-stacked fiber portion 48 of the absorbent core 40. The synthetic fiber layer 42 and the hydrophilic fiber layer 43 are fused and joined together.

  In the consolidated portion 46 of the non-stacked fiber portion 48 of the absorbent core 40, the synthetic fiber layer 42 and the hydrophilic fiber layer 43 of the skin side core wrap sheet 41U, and the synthetic fiber layer 42 and the hydrophilic property of the non-skin side core wrap sheet 41D. From the standpoint of improving the shape retention of the absorbent body 4 after absorbing body fluid by fusing and bonding the fiber layer 43 together, the hydrophilic fiber layers of the skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D. 43 preferably includes a hydrophilic thermoplastic synthetic fiber (not shown) in the non-thermoplastic hydrophilic fiber 45 to be formed. From such a viewpoint, the hydrophilic fiber layer 43 preferably contains at least 20% by mass or more of the hydrophilic thermoplastic synthetic fiber (not shown) with respect to the total mass of the hydrophilic fiber layer 43. The content is preferably 30% by mass or more, and the upper limit is preferably 50% by mass or less.

  When the hydrophilic fiber synthetic layer (not shown) includes a hydrophilic thermoplastic synthetic fiber (not shown), the thermoplastic synthetic fiber 44 (not shown) as the main component of the synthetic fiber layer 42 described above is used as the hydrophilic thermoplastic synthetic fiber (not shown). Can be used in which a hydrophilic oil agent usually used for constituent fibers such as a nonwoven fabric is added to the fibers made of the same material as the above. The hydrophilicity of the hydrophilic thermoplastic synthetic fiber (not shown) may be lower than the hydrophilicity of the non-thermoplastic hydrophilic fiber 45 constituting the hydrophilic fiber layer 43, but the synthetic fiber layer 42 is constituted. The hydrophilicity of the thermoplastic synthetic fiber 44 is preferably higher.

  The pattern of the shape of the consolidated portion 46 is a dot shape formed from a circle or a polygon, a band shape, or a combination of these, and is arranged continuously or dispersed in the vertical direction X. In the diaper 1, As shown in FIG. 1 and FIG. 3, the absorbent body 4 is viewed in plan, and the pattern of the compacted portion 46 is a dot-like pattern formed from a circle. And in the diaper 1, such a circular compaction part 46 is distributedly arranged in the vertical direction X. The area of the consolidated portion 46 (the total area of the plurality of consolidated portions 46 arranged in the two non-stacked fiber portions 48 in the diaper 1) (S2) should be changed as appropriate according to the area of the unstacked fiber portion 48. Can do.

  When the diaper 1 is viewed in a plan view as shown in FIGS. 1 and 3, the ratio ((S2 / S1) × 100) of the area (S2) of the consolidated portion 46 to the area (S1) of the non-stacked fiber portion 48 is From the viewpoint of achieving both the stable joint strength of the consolidated portion 46 and the softness of the consolidated portion 46, it is 10% or more, preferably 20% or more, more preferably 25% or more, and 80%. Or less, preferably 75% or less, more preferably 70% or less, and particularly preferably less than 50%. Specifically, it is 10% or more and 80% or less, preferably 20% or more and 75% or less, more preferably 25% or more and 70% or less, and particularly preferably 25% or more and less than 50%. preferable. Here, the area of each consolidated portion 46 means the area of the portion surrounded by the outer periphery of the consolidated portion 46 in plan view.

As shown in FIG. 5, the hydrophilic fiber layer 43 of the skin-side core wrap sheet 41 </ b> U and the hydrophilic fiber layer 43 of the non-skin-side core wrap sheet 41 </ b> D come into contact with each consolidated portion 46 of the non-stacked fiber portion 48. ing. And in the skin side core wrap sheet | seat 41U, the non-thermoplastic hydrophilic fiber 45 which comprises the hydrophilic fiber layer 43 passes through the synthetic fiber layer 42 of the outer surface side, and is exposed to the skin opposing surface side of the absorber 4. . In the non-skin-side core wrap sheet 41D, the non-thermoplastic hydrophilic fibers 45 constituting the hydrophilic fiber layer 43 pass through the outer synthetic fiber layer 42 and are exposed to the non-skin facing surface side of the absorbent body 4. ing. Preferably, the consolidated portion 46 is a portion consolidated in the thickness direction in the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D. In the diaper 1, this consolidation is performed by heat, ultrasonic waves, or the like. The embossing (squeezing) is accompanied by a fusion promoting means for promoting the melting of the thermoplastic synthetic fiber 44. When pressing with the fusion promoting means on the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D, the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D may be used from either side. Well, you may squeeze both sheets 41U and 41D, but from the viewpoint of promoting melting of the thermoplastic synthetic fiber 44, the outer surface side of the skin-side core wrap sheet 41U or the non-skin-side core wrap sheet 41D. The pressing is preferably performed on the synthetic fiber layer 42 on the outer surface side. The compacted portion 46 has a narrow inter-fiber gap or substantially no inter-fiber gap compared to a portion (non-consolidated portion) other than the consolidated portion 46 in the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D. It is a high-density part that does not exist, and the non-consolidated part is a low-density part with a wide inter-fiber gap compared to the consolidated part 46.

  In the diaper 1, as described above, in each consolidated portion 46, as shown in FIG. 5, the non-thermoplastic hydrophilic fibers 45 constituting the hydrophilic fiber layer 43 of the skin-side core wrap sheet 41U are on the outer surface side. It passes through the synthetic fiber layer 42 and is exposed to the skin facing surface side of the absorbent body 4. Further, the non-thermoplastic hydrophilic fibers 45 constituting the hydrophilic fiber layer 43 of the non-skin-side core wrap sheet 41D pass through the outer synthetic fiber layer 42 and are exposed to the non-skin facing surface side of the absorbent body 4. Yes. And the hydrophilic fiber layer 43 of the skin side core wrap sheet | seat 41U and the hydrophilic fiber layer 43 of non-skin side core wrap sheet | seat 41D are contact | abutting. Therefore, the hydrophilic fiber 45 exposed on the skin facing surface side of the absorbent body 4 and the hydrophilic fiber 45 exposed on the non-skin facing surface side of the absorbent body 4 are hydrophilic fiber layers of the skin-side core wrap sheet 41U. 43 and the hydrophilic fiber layer 43 of the non-skin-side core wrap sheet 41D. In each consolidated part 46, whether the non-thermoplastic hydrophilic fiber 45 on the skin side core wrap sheet 41U side passes through the synthetic fiber layer 42 and is exposed to the skin facing surface side of the absorbent body 4, or non-skin Whether or not the non-thermoplastic hydrophilic fiber 45 on the side core wrap sheet 41D side passes through the synthetic fiber layer 42 and is exposed to the non-skin facing surface side of the absorbent body 4 is determined in the thickness direction of the compacted portion 46. This can be carried out by microscopic observation of a cross section along the (Z direction), specifically by the following method.

<Method for confirming that non-thermoplastic hydrophilic fibers 45 pass through the synthetic fiber layer 42 and are exposed on the skin facing surface side or the non-skin facing surface side of the absorbent body 4 in the consolidated portion>
The sheet to be evaluated (core wrap sheet 41) is dipped in a 0.5% by mass blue aqueous solution (food color No. 1 of Aizen Food Color manufactured by Daiwa Kasei), and left for 3 minutes. The sheet is placed on a previously laid paper (Kim Towel, manufactured by Nippon Paper Crecia Co., Ltd.) with the skin facing surface side facing down, and dehydrated with a load of 3 kPa from above the sheet for 1 minute. By this operation, hydrophilic fibers among the constituent fibers of the evaluation object sheet are dyed.
The compacted portion 46 to be evaluated of the dyed sheet thus obtained is cut along the lateral direction Y of the diaper 1 using a feather blade razor, and the cut surface is a microscope (VHX-1000 made by KEYENCE). ), And the non-thermoplastic hydrophilic fiber 45 is exposed on the skin facing surface side of the absorbent body 4 or on the non-skin facing surface side of the absorbent body 4 in the compacted portion 46. Check whether or not In the consolidated part 46, since the non-thermoplastic hydrophilic fiber 45 is dyed, it is determined whether or not it is exposed to the skin facing surface side of the absorbent body 4 or the non-skin facing surface side of the absorbent body 4. Is easy.

As described above, the consolidated portion 46 is typically formed by embossing with heat, ultrasonic waves, etc., and the synthetic fiber layer of the skin-side core wrap sheet 41U of the consolidated portion 46 formed by such embossing. 42 and the synthetic fiber layer 42 of the non-skin-side core wrap sheet 41D, the thermoplastic synthetic fiber 44 which forms the main body is softened and melted by heat and ultrasonic waves during embossing, so that the original fiber aggregate form is Lost and filmed. In this way, a part of the non-thermoplastic hydrophilic fiber 45 constituting the main body of the hydrophilic fiber layer 43 enters the synthetic fiber layer 42 formed into a film of the consolidated portion 46 (fiber form is lost), and the absorbent body 4 is exposed to the skin facing surface side of 4 or the non-skin facing surface side of the absorber 4. In other words, in the consolidated portion 46, one or more exposed portions of the hydrophilic fibers 45 are present in the synthetic fiber layer 42 formed into a film when the skin facing surface side of the absorbent body 4 is viewed in plan. The hydrophilic fiber 45 constituting the exposed portion is continuous from the skin facing surface side of the skin side core wrap sheet 41U to the non-skin facing surface side. Further, in the consolidated portion 46, one or more exposed portions of the hydrophilic fibers 45 are present in the synthetic fiber layer 42 formed into a film in a plan view of the non-skin facing surface side of the absorbent body 4. The non-thermoplastic hydrophilic fiber 45 constituting the exposed portion is continuous from the non-skin facing surface side to the skin facing surface side of the non-skin side core wrap sheet 41D.

  As described above, in the diaper 1, as shown in FIGS. 2 to 4, the absorbent core 40 constituting the absorbent body 4 is covered with the skin-side core wrap sheet 41 </ b> U and the non-skin-side core wrap sheet 41 </ b> D, Each of the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D is disposed on the inner surface side in contact with the absorbent core 40 and has a hydrophilic fiber layer 43 mainly composed of non-thermoplastic hydrophilic fibers 45. And a synthetic fiber layer 42 that is arranged on the outer surface side in contact with the hydrophilic fiber layer 43 and is composed mainly of the thermoplastic synthetic fiber 44. Further, in the non-stacking portion 48 of the absorbent core 40, as shown in FIGS. 4 and 5, the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are integrated with each other via the compaction portion 46. ing. Thus, since the skin side core wrap sheet 41U and non-skin side core wrap sheet 41D which cover the absorptive core 40 are united with each other in the compaction part 46, the shape retention of the absorbent body 4 being worn is improved. It is excellent, the absorber 4 is hard to break during wearing, and the feeling of use improves. In particular, since the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D include the synthetic fiber layer 42 made of a nonwoven fabric, the absorbent body 4 is more difficult to break during wearing. In addition, when the body fluid absorbed during wearing in the non-stacking portion 48 of the absorbent core 40 is taken into the absorbent body 4 from the periphery of the consolidated portion 46 and the consolidated portion 46, the skin-side core wrap sheet 41U and the non-woven fabric portion The skin-side core wrap sheet 41D is easily transmitted in the surface direction via the hydrophilic fiber layer 43 in contact with the absorbent core 40, the liquid diffusibility is improved, and the utilization efficiency of the absorbent body 4 is improved. Here, if the hydrophilicity of the thermoplastic synthetic fiber 44 of the synthetic fiber layer 42 is lower than the hydrophilicity of the non-thermoplastic hydrophilic fiber 45, the bodily fluid once absorbed by the absorbent body 4 is the hydrophilic fiber layer 43. The synthetic fiber layer 42 disposed on the outer surface side that comes into contact with the skin hardly returns to the wearer's skin side, and the feeling of use of the diaper 1 is improved.

  Moreover, in the diaper 1, in each compaction part 46, as shown in FIG. 5, the non-thermoplastic hydrophilic fiber 45 of the skin side core wrap sheet | seat 41U passes the synthetic fiber layer 42, and the skin opposing surface side of the absorber 4 And the non-thermoplastic hydrophilic fiber 45 of the non-skin-side core wrap sheet 41D passes through the synthetic fiber layer 42 and is exposed to the non-skin-facing surface side of the absorbent body 4, and the skin-side core wrap sheet 41U The hydrophilic fiber layer 43 and the hydrophilic fiber layer 43 of the non-skin-side core wrap sheet 41D are in contact with each other. Therefore, in each consolidated portion 46, the hydrophilic fibers 45 exposed on the skin-facing surface side of the absorbent body 4 easily function as a body fluid passage (fluid trigger) and are located in the non-stacked portion 48. The body fluid on the skin facing surface of the body 4 is easily diffused into the hydrophilic fiber layer 43 through the compacted portion 46 (exposed portion of the hydrophilic fiber 45) and quickly taken into the absorbent core 40. In particular, when the non-stacked fiber portion 48 of the absorbent core 40 is disposed at least in the crotch portion 1M, the absorbent core 40 can be promptly introduced into the absorbent core 40 via the consolidated portions 46 disposed in the non-stacked fiber portion 48. It becomes easy to be taken in.

From the viewpoint of further achieving the above-described effects, the diaper 1 preferably includes one or more of the following configurations.

When ten pieces are arbitrarily selected from the plurality of consolidated portions 46 existing at the position of the non-stacked fiber portion 48 of the absorbent core 40, in the ten consolidated portions 46, in other words, on the skin facing surface side of the absorbent body 4. For example, a non-thermoplastic hydrophilic fiber 45 (a constituent fiber of the hydrophilic fiber layer 43 of the skin-side core wrap sheet 41U) is exposed on the skin facing surface side of the compacted portion 46 (hereinafter referred to as “hydrophilic portion exposed compaction”). 40% or more, more preferably 50% or more. The ratio calculated by “(number of exposed and consolidated hydrophilic parts / 10) × 100” is preferably 40% or more.
In addition, it is confirmed by the following method whether a certain consolidation part is the said hydrophilic part exposure consolidation part. That is, for the consolidated portion to be evaluated, it is confirmed by the above method whether or not the fibers (hydrophilic fibers 45) of the hydrophilic fiber layer 43 are exposed on the skin facing surface side of the consolidated portion. When the exposure can be confirmed even at one place, the consolidated portion is assumed to be the hydrophilic portion exposed consolidated portion.
Further, the length in the longitudinal direction of the evaluation sheet in the consolidated portion 46 (when the planar view shape of the consolidated portion 46 is an anisotropic shape such as a rectangular shape) or the length in the longitudinal direction X (the planar view shape of the consolidated portion 46 is circular). In the case of an isotropic shape such as a shape) and the lateral length of the evaluation sheet (when the planar view shape of the consolidated portion 46 is anisotropic) or the length in the lateral direction Y (the planar view shape of the consolidated portion 46 is When the isotropic shape) exceeds 2 mm, the range of 2 mm in the longitudinal direction of the evaluation sheet × 2 mm in the lateral direction of the evaluation sheet in the consolidated portion 46 is treated as one consolidated portion, and the hydrophilic fibers 45 are exposed. The ratio of the confirmation and the hydrophilic portion exposed consolidated portion is calculated.

  In the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D, the synthetic fiber layer 42 is lower in hydrophilicity than the hydrophilic fiber layer 43 in parts other than the compacted part 46, in other words, hydrophilic. The hydrophilic fiber layer 43 preferably has a higher hydrophilicity than the synthetic fiber layer 42. The hydrophilicity of a sheet | seat (layer) here is evaluated by the water droplet loss | disappearance rate measured by the following method. The smaller the water drop disappearance value, the lower the hydrophilicity, and the larger the water drop disappearance value, the higher the hydrophilicity. Therefore, it is preferable that the magnitude relationship of “water droplet disappearance rate of the synthetic fiber layer 42 <water droplet disappearance rate of the hydrophilic fiber layer 43” is satisfied.

<Measurement method of water drop disappearance rate>
The sheet to be evaluated (for example, the skin-side core wrap sheet 41U or the synthetic fiber layer 42 or the hydrophilic fiber layer 43) is fixed in the air so that the surface is horizontal, and at any 20 locations on the upper surface of the sheet, A water drop (1 drop 2 μl) of physiological saline (saline solution having a concentration of 0.9% by mass) is dropped using a microsyringe. If the sheet to be evaluated has a high degree of hydrophilicity, water droplets are quickly absorbed by the sheet after dropping, and if the sheet has a low degree of hydrophilicity, it remains unabsorbed and remains on the upper surface of the sheet. The determination of the disappearance of the water droplet is performed by visually observing the upper surface of the sheet 10 seconds after the water droplet is dropped. Further, the water drop disappearance rate (%) is obtained by calculating the ratio of the spots where the water drops disappeared within 10 seconds out of the measurement at 20 places.

It is preferable that the former is smaller than the latter in the ratio between the water droplet disappearance rate of the synthetic fiber layer 42 other than the consolidated portion 46 and the water droplet disappearance rate of the hydrophilic fiber layer 43 other than the consolidated portion 46.
The water drop disappearance rate of the synthetic fiber layer 42 other than the consolidated portion 46 is preferably 50% or less, more preferably 40% or less, and the lower limit is 0%.
The water droplet disappearance rate of the hydrophilic fiber layer 43 other than the consolidated portion 46 is preferably 75% or more, more preferably 80% or more, and the upper limit is 100%.
The adjustment of the water droplet number disappearance rate, that is, the adjustment of the hydrophilicity is carried out by adjusting the type of the constituent fiber (thermoplastic synthetic fiber 44) of the synthetic fiber layer 42 and the constituent fiber (hydrophilic fiber 45) of the hydrophilic fiber layer 43, the hydrophobizing agent ( It can be carried out mainly by using a synthetic fiber layer 42) or a hydrophilizing agent (mainly for the hydrophilic fiber layer 43).

  In the diaper 1, the absorbent core 40 constituting the absorbent body 4 is configured to include a water-absorbing polymer and cellulosic fibers. The content mass ratio of the water-absorbing polymer and cellulosic fibers is the former: the latter The ratio is preferably 1: 1.5 to 1: 0, more preferably 1: 1.3 to 1: 0, and may not contain cellulosic fibers.

  Further, from the viewpoint of promoting diffusion of body fluid such as urine in the longitudinal direction X, the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are each non-thermoplastic that forms the main body of the hydrophilic fiber layer 43. It is preferable that the hydrophilic fibers 45 are oriented in the longitudinal direction X.

The total area of the consolidated portions 46 located in each non-stacked fiber portion 48 of the absorbent core 40 is preferably 120 mm ² or more, more preferably 200 mm ² or more, and preferably 2400 mm ² or less, more preferably 2000 mm ² or less. is there.

  In the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D, the fiber diameters of the thermoplastic synthetic fiber 44 and the non-thermoplastic hydrophilic fiber 45 are preferably thinner, respectively. Since the fiber diameter of the thermoplastic synthetic fiber 44 forming the main body of the synthetic fiber layer 42 is relatively small, the fiber 44 is more easily melted and deformed due to the consolidation, and the absorbent body 4 side or non-surface side The exposure of the hydrophilic fibers 45 on the skin facing surface side is more likely to occur, and the fiber diameter of the hydrophilic fibers 45 forming the main body of the hydrophilic fiber layer 43 is relatively small, so that the exposure of the fibers 45 is achieved. Is more likely to occur. From the above points, the fineness of the thermoplastic synthetic fiber 44 is preferably 0.7 dtex or more, more preferably 1.0 dtex or more, and preferably 4.4 dtex or less, more preferably 2.2 dtex or less. Further, the thickness of the hydrophilic fiber 45 is circular if it is circular, and if it is elliptical or flat, the length of the major axis is preferably 50 μm or less, more preferably 30 μm or less.

Further, regarding the non-thermoplastic hydrophilic fiber 45, the cross section of the hydrophilic fiber 45 is a perfect circle or a circular shape close to it, so that the exposure on the skin facing surface side or the non-skin facing surface side of the absorbent body 4 is performed. It is preferable from a viewpoint of realizing more reliably.
Moreover, the viewpoint which ensures the continuity from the exposed part in the skin opposing surface side or the non-skin opposing surface side of the absorber 4 to the synthetic fiber layer 42, and performs the function as a liquid introduction path more reliably. Therefore, it is preferable that the hydrophilic fiber 45 has a long fiber length. Specifically, the fiber length of the hydrophilic fiber 45 is preferably 1 mm or more, more preferably 3 mm or more, and preferably 20 mm or less, more preferably 15 mm or less.

The basis weight of the synthetic fiber layer 42 is preferably relatively small. When the basis weight of the synthetic fiber layer 42 is excessive, film formation of the synthetic fiber layer 42 (thermoplastic synthetic fiber 44) in the compacted portion 46 is excessively promoted. The surface side is completely blocked by the synthetic fiber layer 42 formed into a film, and the non-thermoplastic hydrophilic fiber 45 may be difficult to be exposed on the skin facing surface side or the non-skin facing surface side of the absorbent body 4. From the above points, the basis weight of the synthetic fiber layer 42 is preferably 0.1 g / m ² or more, more preferably 0.
. It is 3 g / m ² or more, preferably 10 g / m ² or less, more preferably 8 g / m ² or less.

The skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are separated from the raw sheet of the synthetic fiber layer 42 (typically, a nonwoven fabric mainly composed of the thermoplastic synthetic fiber 44). Alternatively, it may be a laminate in which the raw sheet of the hydrophilic fiber layer 43 (typically, paper mainly composed of non-thermoplastic hydrophilic fibers 45) is overlapped. The absorbent body 4 described above covers the absorbent core 40 using the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D made of such a laminated body, and the inside of the non-filament portion 48 of the absorbent core 40. , A fusion promoting means for accelerating the melting of the thermoplastic synthetic fiber 44 such as heat and ultrasonic waves with respect to a predetermined overlapping portion of the skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D made of a laminate. It can be manufactured by embossing (squeezing). By this embossing process, the thermoplastic synthetic fiber 44 in the raw fabric sheet of the synthetic fiber layer 42 on the outer surface side is melted and deformed to form a film, and the hydrophilic fiber in the raw fabric sheet of the hydrophilic fiber layer 43 on the inner surface side. 45 tends to be exposed on the surface side of the filmed portion. In the absorbent body 4 manufactured by such a method, the embossed portion is the consolidated portion 46, and the synthetic fiber layer 42 and the hydrophilic fiber layer 43 are joined and integrated via the consolidated portion 46. Yes. Thus, when using the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D formed of a laminate composed of two original fabric sheets, the basis weight of each hydrophilic fiber layer 43 is as paper. From the viewpoint of maintaining the form, it is preferably 3.0 g / m ² or more, more preferably 4.8 g / m ² or more, and preferably 30 g / m ² or less, more preferably 25 g / m ² or less.

  Further, the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are formed using a raw fabric sheet of the synthetic fiber layer 42, a paper slurry containing non-thermoplastic hydrophilic fibers 45, and a papermaking net. It may be a sheet produced by a known wet papermaking method. Specifically, first, a raw sheet of the synthetic fiber layer 42 is placed on a papermaking net. Next, the stock slurry containing the hydrophilic fibers 45 is poured into the original fabric sheet on the papermaking net. The water in the stock slurry poured in sequentially passes through the raw sheet and the papermaking net and flows down from below the papermaking net. The hydrophilic fibers 45 in the stock slurry are the constituent fibers (heat The wet sheet having a two-layer structure containing the hydrophilic fiber 45 and the thermoplastic synthetic fiber 44 is formed on the papermaking net. Suction means may be arranged on the opposite side of the original sheet with the papermaking net in between, and the suction means may promote dewatering of the original sheet. And the target skin side core wrap sheet | seat 41U and non-skin side core wrap sheet | seat 41D are manufactured by drying this wet sheet | seat by the various drying means employ | adopted with the wet papermaking method. The absorbent body 4 described above covers the absorbent core 40 using the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D manufactured as described above, and in the non-filament portion 48 of the absorbent core 40. , Embossing (squeezing) with melting promoting means for accelerating the melting of thermoplastic synthetic fiber 44 such as heat, ultrasonic waves, etc., on the predetermined overlapping portion of skin side core wrap sheet 41U and non-skin side core wrap sheet 41D It can manufacture by giving. In the absorbent body 4 manufactured by such a method, the embossed portion is the consolidated portion 46, and the synthetic fiber layer 42 and the hydrophilic fiber layer 43 are integrated with each other in the consolidated portion 46. It is also made by the entanglement of both fibers 44 and 45.

  In the skin-side core wrap sheet 41U manufactured by such a wet papermaking method, the opposite side to the papermaking net of the original sheet is the so-called wire side (the side opposite to the stock slurry supply side). Since the non-thermoplastic hydrophilic fiber 45 is unevenly distributed, the wire surface side becomes the hydrophilic fiber layer 43. The distribution state of the hydrophilic fibers 45 in the skin-side core wrap sheet 41U can be adjusted by appropriately adjusting the diameter and pitch of the dewatering holes of the papermaking net. In particular, after pouring the stock slurry containing the hydrophilic fibers 45 into the original sheet, and then spraying a high-pressure water flow on the felt surface side of the original sheet, in the compacted portion 46 formed by the subsequent embossing, It is preferable because the hydrophilic fibers 45 are easily exposed on the skin facing surface side or the non-skin facing surface side of the absorbent body 4.

  As mentioned above, although this invention was demonstrated based on the embodiment, this invention can be changed suitably, without being restrict | limited to the said embodiment.

For example, in the diaper 1, the plan view as shown in FIGS. 1 and 3, the pattern of the consolidated portion 46 is a dot-like pattern formed from a circle, but as shown in FIG. It is formed by a dot-like pattern formed from a polygon, and may be a pattern distributed in the vertical direction X. Further, as shown in FIGS. 6B and 6C, the consolidation portion 46 may be formed in a pattern formed in a linear shape, and may be a pattern distributed in the vertical direction X. . Preferably, the linear compacted portion 46 shown in FIG. 6B is formed to extend in parallel to the lateral direction Y from one side edge along the longitudinal direction X of each non-stacked fiber portion 48 toward the other side edge. The non-stacking portions 48 are arranged at a certain interval in the longitudinal direction X, and are distributed in the longitudinal direction X. Also,
Preferably, the linear compaction portion 46 shown in FIG. 6C is an imaginary line extending in parallel to the lateral direction Y from one side edge along the longitudinal direction X of each non-stacked fiber portion 48 toward the other side edge. Are arranged so as to intersect with each other in the longitudinal direction X of the non-fiber-stacking portion 48 with a certain interval, and are distributed in the longitudinal direction X. Further, as shown in FIG. 6 (d), the consolidated portion 46 is formed in a pattern formed in a linear shape, and the linear consolidated portion 46 is formed from one end in the longitudinal direction X of each non-stacked fiber portion 48. It may be formed to extend in parallel to the vertical direction X toward the other end, and may be arranged at a certain interval in the horizontal direction Y of the non-stacking portion 48. In addition, the pattern of the consolidated portion 46 may be a dot shape formed from a circle or a polygon, or a pattern in which a band shape is combined.

  Further, the core wrap sheet 41 of the diaper 1 is composed of one sheet as shown in FIG. 2, but the skin facing surface side of the absorbent core 40 is covered with the skin side core wrap sheet 41U, and the non-absorbent core 40 is non-coated. The skin facing surface side may be covered with a second non-skin side core wrap sheet 41D different from the skin side core wrap sheet 41U, and the absorbent core 40 may be wrapped. When the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are separate bodies, the non-skin-side core wrap sheet 41D may be the same as or different from the skin-side core wrap sheet 41U with regard to its composition and material. Good.

  In addition, from the viewpoint of improving absorbability, leakproofness, and the like, liquid permeability made of paper or various nonwoven fabrics, which is also called a sublayer, is provided between the top sheet 2 and the absorbent body 4 (skin-side core wrap sheet 41U). A sheet may be interposed. From the same viewpoint, a groove formed by integrally compacting the topsheet 2 and the absorbent body 4 may be formed on the skin facing surface of the diaper 1.

  In addition, the absorbent article of the present invention is not limited to a deployable disposable diaper, but widely includes articles used to absorb body fluids (urine, loose stool, menstrual blood, sweat, etc.) discharged from the human body, and is a pants type. Disposable diapers, sanitary napkins, sanitary shorts, and the like are also included.

1 Unfoldable disposable diaper (absorbent article)
2 Top sheet 3 Back sheet 4 Absorbent body 40 Absorbent core 41 Core wrap sheet 41U Skin side core wrap sheet 41D Non-skin side core wrap sheet 42 Synthetic fiber layer 43 Hydrophilic fiber layer 44 Thermoplastic synthetic fiber 45 Non-thermoplastic hydrophilic Fiber 46 Consolidation part 48 Non-stacked part 1F Abdominal side part 1M Crotch part 1R Back side part X Longitudinal direction Y Lateral direction

Claims (9)

It has an absorbent body having a liquid-retaining absorbent core and a core wrap sheet that covers the absorbent core, and extends in the longitudinal direction extending from the wearer's abdominal side to the back side through the crotch part and perpendicular to the longitudinal direction. And an absorbent article comprising a crotch part arranged in the crotch part and a ventral part and a dorsal part extending in the front and back thereof,
The absorbent core has a non-stacked portion that penetrates in the thickness direction,
The core wrap sheet has a skin side core wrap sheet covering the skin facing surface of the absorbent core, and a non-skin side core wrap sheet covering the non skin facing surface of the absorbent core,
Each of the skin-side core wrap sheet and the non-skin-side core wrap sheet is disposed on the inner surface side in contact with the absorbent core and has a hydrophilic fiber layer mainly composed of non-thermoplastic hydrophilic fibers, and A laminated sheet having a synthetic fiber layer mainly composed of a thermoplastic synthetic fiber and disposed on an outer surface side in contact with the hydrophilic fiber layer;
In the said non-stacking part of the said absorptive core, the said skin side core wrap sheet | seat and the said non-skin side core wrap sheet | seat are mutually integrated through the compaction part. In the consolidated portion of the non-stacked fiber portion, the hydrophilic fiber layer of the skin-side core wrap sheet is in contact with the hydrophilic fiber layer of the non-skin-side core wrap sheet,
In the skin-side core wrap sheet, the non-thermoplastic hydrophilic fibers constituting the hydrophilic fiber layer pass through the synthetic fiber layer on the outer surface side and are exposed on the skin-facing surface side of the absorber.
In the non-skin side core wrap sheet, the non-thermoplastic hydrophilic fibers constituting the hydrophilic fiber layer pass through the synthetic fiber layer on the outer surface side and are exposed on the non-skin facing surface side of the absorber. The absorbent article according to claim 1. The hydrophilic fiber layer of the skin-side core wrap sheet and the non-skin-side core wrap sheet includes a hydrophilic thermoplastic synthetic fiber in the non-thermoplastic hydrophilic fiber constituting the skin-side core wrap sheet,
In the consolidated portion of the non-stacked fiber portion, the hydrophilic fiber layer and the synthetic fiber layer of the skin-side core wrap sheet, and the hydrophilic fiber layer and the synthetic fiber layer of the non-skin-side core wrap sheet, The absorptive article according to claim 1 or 2 which is melt-integrated and joined. In each of the skin side core wrap sheet and the non-skin side core wrap sheet,
The thermoplastic synthetic fiber constituting the synthetic fiber layer has a hydrophilicity lower than that of the non-thermoplastic hydrophilic fiber constituting the hydrophilic fiber layer. The absorbent article according to item 1.   The absorbent article according to any one of claims 1 to 4, wherein the non-stacked fiber portion is disposed at least in the crotch portion of the absorbent core and extends in the longitudinal direction.   When the absorber is viewed in plan, the ratio of the area of the compacted part to the area of the non-stacked fiber part is 10% or more and 80% or less, and the pattern of the shape of the compacted part is circular or polygonal The absorbent article according to any one of claims 1 to 5, wherein the absorbent article is formed in a dot shape, a band shape, or a combination of these, and is continuously or dispersed in the vertical direction.   Each of the skin-side core wrap sheet and the non-skin-side core wrap sheet includes a spunbond nonwoven fabric or a spunbond-meltblown-spunbond nonwoven fabric, and an average interfiber distance of fibers constituting the nonwoven fabric is 10 μm. The absorptive article given in any 1 paragraph of Claims 1-6 which are above 200 micrometers or less. The hydrophilic fiber layer of the skin-side core wrap sheet and the non-skin-side core wrap sheet includes pulp, cotton, or rayon in the non-thermoplastic hydrophilic fiber that constitutes,
The absorptive article according to any one of claims 1 to 7. The absorbent core includes a water absorbent polymer;
The absorptive article given in any 1 paragraph of Claims 1-8 whose content mass ratio of said water-absorbing polymer and cellulosic fiber is former: latter = 1: 1.5-1: 0.

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