JP6912979B2 - Absorbent article - Google Patents

Description

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

As absorbent articles such as disposable diapers, generally, a liquid-permeable front sheet forming a skin-facing surface, a liquid-impermeable back sheet forming a non-skin facing surface, and an absorbent arranged between these two sheets. It is known that the absorbent body includes an absorbent core containing an absorbent material such as wood pulp or a water-absorbent polymer, and a core wrap sheet that covers the outer surface of the absorbent core.

The core wrap sheet functions as a sheet for receiving the absorbent material at the time of manufacturing the absorbent body, and plays a role of wrapping and shaping the absorbent core after manufacturing. As the core wrap sheet, a water-permeable sheet such as thin paper or absorbent paper is generally used. However, from the viewpoint of improving the strength of the absorbent body after absorption of body fluid, the applicant has first made a non-woven fabric water-permeable sheet. It has been proposed to use a sex sheet (Patent Documents 1 and 2).

In Patent Document 1, a non-stacked fiber portion is provided in a liquid-retaining absorbent core, and in the non-stacked fiber portion, a skin-side core wrap sheet covering the absorbent core and a non-skin-side core wrap sheet are joined. An absorbent article comprising the absorber is described. Patent Document 1 describes that a hydrophilic non-woven fabric made of fibers that have been subjected to a hydrophilic treatment is used as the core wrap sheet.

Further, Patent Document 2 describes that the core wrap sheet covering the absorbent core has a two-layer structure including a first layer made of a non-woven fabric and a second layer made of a non-woven fabric having different liquid permeation velocities. There is.

Japanese Unexamined Patent Publication No. 2016-83194 Japanese Unexamined Patent Publication No. 2013-180171

According to the absorbent article described in Patent Document 1, the shape-retaining property of the absorber is excellent, the absorber is not easily broken during wearing, and the usability is improved. Further, according to the absorbent article described in Patent Document 2, the liquid permeability and the liquid diffusivity are improved, and the utilization efficiency of the absorber is improved. However, there has been a need to further improve the shape-retaining property of the absorber during wearing, further improve the liquid diffusivity, and further improve the utilization efficiency of the absorber. In addition, Patent Document 1 does not describe anything about using a multilayer structure non-woven fabric for the core wrap sheet. Further, Patent Document 2 describes that a non-woven fabric having a multi-layer structure is used for the core wrap sheet, but there is room for improvement in the fibers constituting each layer.

Therefore, the present invention is to provide an absorbent article capable of eliminating the above-mentioned drawbacks of the prior art.

The present invention comprises an absorber having a liquid-retaining absorbent core and a core wrap sheet covering the absorbent core, in a longitudinal direction extending from the ventral side of the wearer to the dorsal side via the crotch portion. An absorbent article having a lateral direction orthogonal to the crotch portion, a crotch portion arranged in the crotch portion, and ventral and dorsal portions extending in front of and behind the crotch portion, wherein the absorbent core is in the 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. It has a core wrap sheet, and the skin side core wrap sheet and the non-skin side core wrap sheet are respectively arranged on the inner surface side in contact with the absorbent core and are mainly composed of non-thermoplastic hydrophilic fibers. It is a laminated sheet having a hydrophilic fiber layer and a synthetic fiber layer arranged on the outer surface side in contact with the hydrophilic fiber layer and composed mainly of thermoplastic synthetic fibers, and is the non-absorbent core. In the synthetic fiber portion, the skin-side core wrap sheet and the non-skin-side core wrap sheet are absorbent articles in which the skin-side core wrap sheet and the non-skin-side core wrap sheet are integrated with each other via a compaction portion.

According to the present invention, there is provided an absorbent article having excellent shape retention of the absorbent body during wearing, further improving the liquid diffusivity, and further improving the utilization efficiency of the absorbent body.

FIG. 1 is a plan view schematically showing a skin-facing surface, that is, a surface sheet side of a deployable disposable diaper according to an embodiment of the absorbent article of the present invention, and the elastic members of each part are stretched and expanded in a plane shape. It is a plan view in the unfolded state. FIG. 2 is a cross-sectional view schematically showing a cross section taken along line II-II of FIG. FIG. 3 is a plan view of the absorber provided in the disposable diaper shown in FIG. FIG. 4 is a cross-sectional view schematically showing the IV-IV line cross section of FIG. FIG. 5 is a cross-sectional view schematically showing a cross section of the absorber provided with the disposable diaper shown in FIG. 1 along the thickness direction of the consolidated portion. 6 (a) and 6 (b) are plan views schematically showing other patterns of the consolidated portion in the absorber according to the present invention, respectively.

Hereinafter, the absorbent article of the present invention will be described with reference to the drawings based on an example of a deployable disposable diaper which is a preferred embodiment thereof. 1 and 2 show the deployable disposable diaper 1 of the present embodiment. The diaper 1 includes an absorber 4 having a liquid-retaining absorbent core 40 and a core wrap sheet 41 covering the absorbent core 40. The diaper 1 includes a vertical direction X extending from the ventral side of the wearer to the dorsal side via the crotch portion and a lateral direction Y orthogonal to the vertical direction X, and extends to the inseam 1M arranged in the crotch portion and the front and back thereof. It includes an existing ventral portion 1F and a dorsal portion 1R. The ventral side 1F, the inseam 1M, and the dorsal side 1R correspond to each region when the diaper 1 is divided into three equal parts in the vertical direction X. The inseam 1M has an excretion portion facing portion that is arranged to face the excretion portion of the wearer's penis, anus, etc. when the diaper 1 is worn, and the excretion portion facing portion is usually in the vertical direction X of the diaper 1. It is located in or near the center. The thickness direction, which is a vertical direction orthogonal to the plane direction including the vertical direction X and the horizontal direction Y, will be described as the Z direction.

As shown in FIGS. 1 and 2, the diaper 1 is arranged 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. A liquid-permeable surface sheet 2 that can come into contact with the wearer's skin when worn, and a liquid diaper that is arranged on the non-skin facing surface side of the absorber 4 and is located farther from the wearer's skin than the absorber 4. It includes a permeable or water-repellent back sheet 3. In a plan view as shown in FIG. 1, the diaper 1 has a vertically long hourglass shape in which the central portion of the vertical direction X located at the inseam 1M is constricted inward and is long in one direction, that is, the vertical direction X. The front surface sheet 2 and the back surface sheet 3 each have a size larger than that of the absorber 4 interposed between the two sheets 2 and 3, 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" is a surface of the absorbent article or its constituent member (for example, the absorbent core 40) that is directed toward the skin side of the wearer when the absorbent article is worn, that is, relatively. The side close to the wearer's skin, and the "non-skin facing surface" is the surface of the absorbent article or its constituent members that faces the opposite side (clothing side) of the absorbent article when the absorbent article is worn, that is, relative to the skin. It is the side far from the wearer's skin. In addition, "when worn" here means a state in which a normal proper wearing position is maintained.

A band-shaped elastic member 11 is formed between the front surface sheet 2 and the back surface sheet 3 at the waist portion of each of the ventral side portion 1F and the dorsal side portion 1R, that is, the end portion in the vertical direction X, which is an abbreviation for the lateral direction Y of the diaper 1. It is fixed in a laterally extended state over the entire length, whereby waist gathers are formed on the waist portion when the diaper 1 is worn due to the contraction of the elastic member 11. Further, a plurality of thread-like elastic members 12 are fixed in a laterally extended state between the front surface sheet 2 and the back surface sheet 3 in the waist circumference portion corresponding to the waist circumference of the wearer in the dorsal side portion 1R. As a result, gathers around the waist are formed by the contraction of the elastic member 12 around the waist when the diaper 1 is worn. Further, side sheets 5 are arranged on both the left and right sides along the vertical direction X on the surface sheet 2 side of the diaper 1, that is, the skin facing surface side. The side sheet 5 has an inner edge portion along the vertical direction X and an outer edge portion located outside the inner edge portion in the horizontal direction Y and along the vertical direction X, and has a plane as shown in FIG. Visually, the inner edge portion overlaps with the absorber 4, and the outer edge portion extends outward in the horizontal direction Y from the side edge of the absorber 4 along the vertical direction X, and as shown in FIG. 2, the back surface sheet. It is joined with 3. A thread-like elastic member 13 is fixed in an extended state along the vertical direction X between the side seat 5 and the back seat 3 in the left and right leg portions arranged around the wearer's legs. A pair of leg gathers are formed on the leg portion when the diaper 1 is worn due to the contraction of the elastic member 13. Further, a thread-like elastic member 14 is fixed to the inner edge portion of the side sheet 5 in an extended state along the vertical direction X, and the inner edge portion is at least 1M in the inseam, specifically, for example. The inseam 1M, the ventral 1F, and the dorsal 1R near the inseam 1M are free ends that are not joined to the surface sheet 2 and other components of the diaper 1, and are ventral. The front and rear ends of the vertical direction X on the 1F and the dorsal side 1R are joined to the surface sheet 2 (not shown). Due to the configuration of the side seat 5, the contraction force of the elastic member 14 acts in the vertical direction X when the diaper 1 is worn, and the side seat 5 has at least the inner edge of the crotch portion 1M which is a free end. In, a pair of left and right leak-proof cuffs are formed by standing up toward the wearer's skin starting from the joint with the back surface sheet 3. The front surface sheet 2, the back surface sheet 3, the absorber 4, the side sheets 5, and the elastic members 11 to 14 are bonded to each other by a known bonding means such as a hot melt adhesive.

As shown in FIG. 1, a pair of fastening tapes 6 and 6 are provided on both side edges of the dorsal portion 1R of the diaper 1 along the vertical direction X. A fastening portion 61 made of a male member of a mechanical hook-and-loop fastener is attached to the fastening tape 6. Further, a landing region 7 made of a female member of a mechanical hook-and-loop fastener is formed on the non-skin facing surface of the ventral side 1F of the diaper 1. In the landing region 7, a female member of a mechanical hook-and-loop fastener is attached to the non-skin facing surface of the back surface sheet 3 forming the non-skin facing surface on the ventral side 1F by a known joining means such as an adhesive or a heat seal. It is formed by joining and fixing, and the fastening portion 61 of the fastening tape 6 can be detachably fastened.

As the surface sheet 2, various materials conventionally used for absorbent articles such as disposable diapers can be used without particular limitation, and it is assumed that the surface sheet 2 is a liquid permeable sheet capable of permeating body fluids such as urine and feces. As the material, a woven fabric made of synthetic fibers or natural fibers, a non-woven fabric, a porous sheet, or the like can be used. As an example of the surface sheet 2, a non-woven fabric made of a natural fiber such as cotton or a non-woven fabric made of various synthetic fibers subjected to a hydrophilic treatment can be used. For example, a core-sheath structure type (including side-by-side type) composite fiber using polypropylene or polyester as a core component and polyethylene as a sheath component is made into a web by carding, and then a non-woven fabric (after that, a hole is opened at a predetermined position) by an air-through method. Treatment may be applied). Further, from the viewpoint of high liquid permeability (dry feeling), a perforated 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 ones are preferable. Used. Specifically, in order to obtain sufficient water vapor permeability, a film made of a synthetic resin such as polyethylene in which fine powder composed of a filler such as calcium carbonate is dispersed is stretched, and a porous film provided with fine pores is a back sheet. Can be suitably used as 3.
As the side sheet 5, a sheet that can be used as the back sheet 3 can be used.

As shown in FIGS. 2 and 3, the absorber 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 the non-stacked portion 48 described later. In the plan view as shown in FIGS. 1 and 3, the absorbent core 40 constituting the absorber 4 has an hourglass shape in which the central portion of the vertical direction X located at the inseam 1M is constricted inward and is in the vertical direction X. It has a long vertically long 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 the absorbent material, various materials conventionally used for absorbent articles such as disposable diapers can be used without particular limitation. For example, cellulosic fibers such as wood pulp and synthetic fibers treated with a hydrophilic agent can be used. Such as hydrophilic fibers and water-absorbent polymers can be mentioned. As the structure of the absorbent core 40, a structure in which a hydrophilic fiber stack, a structure in which a water-absorbent polymer is supported on the stack, or a structure consisting of only a water-absorbent polymer can be exemplified.

The absorbent core 40 has a non-stacked portion 48 penetrating in the thickness direction Z. The non-stacked fiber portion 48 is preferably arranged at least in the inseam 1M, and in the diaper 1, in the plan view as shown in FIG. 1, the entire inseam 1M is included, and the inseam 1M to the ventral portion 1F. It extends in the vertical direction X over a part and from the inseam 1M to a part of the dorsal side 1R. Here, the fact that the non-stacked fiber portion 48 is arranged at least in the crotch lower portion 1M means that the non-stacked fiber portion 48 extending in the vertical direction X is applied to the crotch lower portion 1M as much as possible. Further, it is preferable that the non-stacked fiber portion 48 does not have any absorbent material forming the absorbent core 40. In the diaper 1, as shown in FIGS. 1 and 2, two non-stacked fiber portions 48 are arranged. The pair of non-stacked fiber portions 48, 48 are formed so as to extend in a strip shape in parallel with the vertical direction X, including the entire crotch portion 1M, respectively.

The basis weight of the absorbent core 40 excluding the non-stacked 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 the 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-folded fiber portion 48 (the total area of the two non-stacked fiber portions 48 in the diaper 1) (S1) is ^{preferably 5 cm 2} or more, and ^{further preferably 10 cm 2} or more. It is preferably 60 cm ² or less, more preferably 50 cm ² or less, specifically 5 cm ² or more and 60 cm ² or less, and even ^{more preferably 10 cm 2} or more and 50 cm ² or less. .. Here, the area of each non-stacked portion 48 means the area of the portion surrounded by the contour of the non-stacked fiber portion 48 in a plan view of the absorbent core 40.

In the diaper 1, the absorbent core 40 is viewed in a plan view as shown in FIG. 3, and the ratio of the area (S1) of the non-stacked portion 48 to the area (surface area) (S0) of the absorbent core 40 ((S1 / S0)). × 100) suppresses the discomfort when wearing the diaper 1, improves the fit, easily promotes the diffusion of body fluid in the vertical direction X, improves the smooth feeling, and improves the utilization efficiency of the absorber 4. From the viewpoint of suppressing and improving the leakage of body fluid by the improvement, it is preferably 2% or more, more preferably 4% or more, more preferably 25% or less, still 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. The area (surface area) (S0) of the absorptive core 40 as used herein means the area of the entire absorptive core 40 when the absorptive core 40 is viewed in a plan view, and is a non-stacked portion included in the absorptive core 40. It shall include an area of 48 (S1).

As shown in FIGS. 2 to 4, the core wrap sheet 41 includes a skin-side core wrap sheet 41U 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. It has 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 in the diaper 1, they are formed of one core wrap sheet 41. Specifically, one core wrap sheet 41 has a length equal to or longer than the length of the absorbent core 40 in the vertical direction X in the vertical direction X, and as shown in FIG. 2 in the horizontal direction Y. The skin-facing surface of the absorbent core 40 is covered, and both side portions of the core wrap sheet 41 along the vertical direction X are caught in the non-skin facing surface side of the absorbent core 40, so that the non-skin facing surface of the absorbent core 40 is non-skinned. The absorbent core 40 is wrapped so as to overlap at the center of the lateral Y on the facing surface. In one core wrap sheet 41 that wraps the absorbent core 40 in this way, the sheet portion that covers 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 portion that covers the skin is the non-skin side core wrap sheet 41D.

As shown in FIG. 4, the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are mainly composed of non-thermoplastic hydrophilic fibers 45 arranged on the inner surface side in contact with the absorbent core 40, respectively. This is a laminated sheet having the hydrophilic fiber layer 43 formed therein and the synthetic fiber layer 42 arranged on the outer surface side in contact with the hydrophilic fiber layer 43 and mainly composed of the thermoplastic synthetic fiber 44. The absorbent core 40, the skin-side core wrap sheet 41U arranged on the skin-facing surface side of the absorbent core 40, and the non-skin-side core wrap sheet 41D arranged 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 a thermoplastic synthetic fiber 44, and the hydrophilic fiber layer 43 is mainly composed of a non-thermoplastic hydrophilic fiber 45. The synthetic fiber layer 42 contains at least 40% by mass or more 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. Further, the hydrophilic fiber layer 43 contains at least 50% by mass or more of the non-thermoplastic hydrophilic fiber 45, and the content of the non-thermoplastic hydrophilic fiber 45 is 100 with respect to the total mass of the hydrophilic fiber layer 43. It may be% by mass.

As shown in FIG. 4, the skin-side core wrap sheet 41U is relatively close to the wearer's skin, and is relatively close to the wearer's skin with the synthetic fiber layer 42 arranged on the outer surface side of the absorbent core 40. It is configured to include a laminated structure (two-layer structure) with the hydrophilic fiber layer 43 on the inner surface side which is far away and abuts on the absorbent core 40. The synthetic fiber layer 42 of the skin-side core wrap sheet 41U is arranged to face the surface sheet 2, and the hydrophilic fiber layer 43 is arranged to face the absorbent core 40. The synthetic fiber layer 42 and the hydrophilic fiber layer 43 are integrated at least via a compaction portion 46 described later, and depending on the manufacturing method, the constituent fibers of both layers 42 and 43 are further entangled with each other, and an adhesive or the like is used. It can also be integrated by other integrating means such as joining means.

As shown in FIG. 4, the non-skin side core wrap sheet 41D is relatively far from the wearer's skin and is relative to the wearer's skin with the synthetic fiber layer 42 arranged on the outer surface side of the absorbent core 40. It is configured to include a laminated structure (two-layer structure) with the hydrophilic fiber layer 43 on the inner surface side that is in contact with the absorbent core 40. The synthetic fiber layer 42 of the non-skin side core wrap sheet 41D is arranged to face the back surface sheet 3, and the hydrophilic fiber layer 43 is arranged to face the absorbent core 40. The synthetic fiber layer 42 and the hydrophilic fiber layer 43 are integrated at least via a compaction portion 46 described later, and depending on the manufacturing method, the constituent fibers of both layers 42 and 43 are further entangled with each other, and an adhesive or the like is used. It can also be integrated by other integrating means such as joining means.

In the core wrap sheet 41 of the diaper 1, the synthetic fiber layer 42 and the hydrophilic fiber layer 43 are both fiber aggregates. The form of such a fiber aggregate is not particularly limited, and examples thereof include non-woven fabric, woven fabric, and paper. In a typical form, the synthetic fiber layer 42 is a non-woven fabric and the hydrophilic fiber layer 43 is paper. In FIGS. 4 and 5, from the viewpoint of facilitating understanding, the thermoplastic synthetic fiber 44 is indicated by a relatively thin line, and the non-thermoplastic hydrophilic fiber 45 is indicated by a relatively thick line. It has nothing to do with the actual fiber thickness.

The skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D are each composed of a non-woven fabric constituting the synthetic fiber layer 42. As the non-woven fabric constituting the synthetic fiber layer 42, those produced by various manufacturing methods can be used without particular limitation, and examples thereof include spunbonded non-woven fabrics, melt-blown non-woven fabrics, spunbond-melt-blown-spunbond non-woven fabrics, and air-through non-woven fabrics. , Spun lace non-woven fabric, resin bond non-woven fabric, needle punch non-woven fabric and the like. It is also possible to use a laminated body in which two or more kinds of these non-woven fabrics are combined, or a laminated body in which these non-woven fabrics and a film or the like are combined. Among these non-woven fabrics, the spunbond non-woven fabric and the spunbond-melt blown-spunbond non-woven fabric have an effect of preventing leakage of an absorbent material such as a water-absorbent polymer contained in the absorbent core 40 as compared with an air-through non-woven fabric or the like. It is preferable because it is excellent in. From the same viewpoint, the average interfiber distance of the spunbonded non-woven fabric or the spunbond-melt blown-spunbond (SMS) non-woven fabric is preferably 10 μm or more, more preferably 20 μm or more, and preferably 200 μm or less, further 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 consolidation portion 46.

<Method of measuring the average interfiber distance of the non-woven fabric constituting the synthetic fiber layer 42>
The average interfiber distance of a fiber aggregate such as a non-woven fabric or paper is calculated by the following formula (1) based on the assumption of Wrotnowski. The following formula (1) is generally used when determining the interfiber distance of a fiber aggregate. Under Wrotnowski's assumptions, the fibers are columnar and the fibers are regularly arranged without intersecting.
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 interfiber distance of the single-layer structure sheet is calculated by the following formula (1).
When the sheet to be measured has a multi-layer structure such as an SMS non-woven fabric, the average interfiber distance of the multi-layer structure sheet is determined according to the following procedure.
First, the average interfiber 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 those for the layer to be measured, respectively, and the thickness t is the thickness direction of the layer to be measured. Measure by microscopic observation of the cross section along. The thickness t, the basis weight W, and the fiber diameter D are average values of the 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, measuring the weight, and then dividing the weight measurement value by an area obtained from the predetermined size. Fiber density ρ (g / cm ³ ) is JIS using a density gradient tube.
Measure according to the measurement method of the density gradient tube method described in the L1015 chemical fiber staple test method (URL is http://kikakurui.com/l/L1015-2010-01.html, JIS handbook fiber-2000 for books, (Description on pages 764 to 765 of the Japanese Standards Association). For the fiber diameter D (μm), 10 fiber cross sections of the cut fibers are measured using a scanning electron microscope (DSC6200 manufactured by Seiko Instruments Co., Ltd.), and the average value thereof is taken as the fiber diameter.
Next, the average interfiber distance of each layer is multiplied by the ratio of the thickness of the layer to the total thickness of the multilayer structure, and the numerical values for each layer thus obtained are totaled to obtain the desired multilayer structure. The average interfiber distance of the constituent fibers of the sheet is obtained. For example, in an SMS non-woven fabric having a three-layer structure composed of two S layers and one M layer, the two S layers are collectively treated as one layer, and the thickness t of the entire three-layer structure is 0.11 mm. When the thickness t of the S layer is 0.1 mm, the average interfiber distance LS of the S layer is 47.8 μm, the thickness t of the M layer is 0.01 mm, and the average interfiber distance LS of the M layer is 3.2 μm. The average interfiber distance between the constituent fibers of the SMS non-woven fabric is 43.8 μm [= (47.9 × 0.1 + 3.2 × 0.01) /0.11].

The preferred skin-side core wrap sheet 41U and non-skin-side core wrap sheet 41D include a synthetic fiber layer 42 made of a spunbonded non-woven fabric or an SMS non-woven fabric having an average interfiber distance within the above range, and the synthetic fiber layer. The thermoplastic synthetic fiber 44, which is the main constituent fiber of 42, and the non-woven hydrophilic fiber 45 such as wood pulp are entangled with each other. If the average interfiber distance of the synthetic fiber layer 42 is too large, the effect of the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D on preventing leakage of the absorbent material from the absorbent core 40 is reduced, particularly. When a water-absorbent polymer having a small particle size is used as the absorbent material, the particles may leak to the outside.

The reason why the spunbonded non-woven fabric or the SMS non-woven fabric is used as the synthetic fiber layer 42 of the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D is that the strength suitable for the core wrap sheet and the inter-fiber distance are compatible, and the absorption performance is achieved. This is because it is excellent in and less likely to cause liquid return. As the thermoplastic synthetic fiber 44 which is the main constituent fiber of these non-woven fabrics, a synthetic fiber (for example, polypropylene fiber) which has not been subjected to the hydrophilic treatment can be exemplified. 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 0.3 g / m 2 or more. It is 10 g / m ² or less, more preferably 8 g / m ² or less.

As the thermoplastic resin which is the material of the thermoplastic synthetic fiber 44, those usually used for constituent fibers such as non-woven fabrics can be used without particular limitation. For example, polyethylene, polypropylene, polybutene-1, polypentene-1, and polypentene-1, And polyolefins such as these random or block copolymers; 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 by using a single thermoplastic resin, or may be a composite fiber formed by using two or more kinds of thermoplastic resins. Examples of the composite fiber include core-sheath type fiber, side-by-side type fiber, split type fiber, alternating arrangement type fiber, and sea-island type 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 made into absorbent articles on the premise that they do not have thermoplasticity as non-thermoplastic hydrophilic fibers 45 constituting the hydrophilic fiber layer 43, respectively. Various conventionally used hydrophilic fibers can be used without particular limitation, and typical ones are cellulose fibers. Examples of the cellulose fiber include wood pulp such as coniferous kraft pulp and broadleaf kraft pulp, natural cellulose fiber such as cotton pulp and non-wood pulp such as walla pulp; and regenerated cellulose fiber such as rayon and cupra, and one of them. Can be used alone or in combination of two or more.
Among these, wood pulp is most preferable from the viewpoint that it easily passes through the gaps of the thermoplastic synthetic fibers 44 constituting the synthetic fiber layer 42 and is easily exposed to the surface because the fiber length of wood pulp is shorter than that of regenerated cellulose or non-wood pulp. Used.

In diaper 1, in each of the skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D, the body liquid once absorbed by the absorbent core 40 is a surface sheet formed by the synthetic fiber layer 42 arranged on the outer surface side of the absorbent core 40. From the viewpoint of preventing the synthetic fiber layer 42 from returning to the second side, the hydrophilicity of the thermoplastic synthetic fiber 44 constituting the synthetic fiber layer 42 is higher than that of the non-thermoplastic hydrophilic fiber 45 constituting the hydrophilic fiber layer 43. Is also preferably low. Further, from the viewpoint of improving the utilization efficiency of the absorbent core 40 by diffusing the body fluid in the hydrophilic fiber layer 43 arranged to face the absorbent core 40, the non-thermoplastic hydrophilic fiber 45 constituting the hydrophilic fiber layer 43 is formed. Is preferably higher in hydrophilicity than the hydrophilicity of the thermoplastic synthetic fibers 44 constituting the synthetic fiber layer 42.

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

<Measurement method of contact angle>
The fibers are 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 respect to the fibers 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 the inkjet water droplet discharge unit (Pulse injector CTC-25 manufactured by Cluster Technology Co., Ltd., having a discharge unit hole diameter of 25 μm) is set to 20 picolitres, and water droplets are dropped directly above the fibers. The state of dripping is recorded on a high-speed recording device connected to a horizontally installed camera. From the viewpoint of image analysis later, the recording device is preferably a personal computer incorporating a high-speed capture device. In this measurement, an image is recorded every 17 msec. In the recorded video, the first image of water droplets on the fibers is the attached software FAMAS (software version is 2.6.2, analysis method is droplet method, analysis method is θ / 2, image processing algorithm. Is non-reflective, image processing image mode is frame, threshold level is 200, curvature correction is not performed), the angle between the surface of the water droplet that comes into contact with the air and the fiber is calculated, and the contact is made. Make a corner. The fiber taken out from the object to be measured is cut to a fiber length of 1 mm, and the fiber is placed on a sample table of a contact angle meter and maintained horizontally. Measure the contact angles at two different points for each fiber. The contact angle of N = 5 fibers is measured to one digit after the decimal point, and the average value of the measured values at 10 points in total (rounded to the second digit after the decimal point) is defined as the contact angle of the fiber with water. The measurement environment is room temperature 22 ± 2 ° C. and humidity 65 ± 2% RH.

When the constituent member (for example, the core wrap sheet 41) is taken out from the absorbent article and evaluated and measured, if the constituent member is fixed to another constituent member by an adhesive, fusion, or the like, the constituent member is fixed to another constituent member. The fixed portion is removed by applying a solvent, blowing hot air with a dryer, blowing a cold spray (for example, a commercially available product manufactured by Nichiban Co., Ltd.), and then taking out the fixed portion.

In the non-stacked 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. There is. The compaction portion 46 is a thermoplastic synthetic fiber 44 constituting the skin-side core wrap sheet 41U.
The thermoplastic synthetic fibers 44 constituting the non-skin side core wrap sheet 41D may be melted and integrally formed, or may be pressure-bonded by pressure without applying heat to be integrally formed. In the diaper 1, the compaction portion 46 is 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 and integrally forming them. ing. As described above, in the diaper 1, the synthetic fiber layer 42 and the hydrophilic fiber layer 43 of the skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D are formed in the compacted portion 46 of the non-separated fiber portion 48 of the absorbent core 40. The synthetic fiber layer 42 and the hydrophilic fiber layer 43 of the above are fused and integrated.

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 of the skin side core wrap sheet 41U and the synthetic fiber layer 42 and the hydrophilic fiber layer 42 of the non-skin side core wrap sheet 41D. From the viewpoint of improving the shape retention of the absorber 4 after absorbing the body liquid by melting and integrating the fiber layer 43, the hydrophilic fiber layer of the skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D. It is preferable that the non-thermoplastic hydrophilic fiber 45 constituting the 43 contains a hydrophilic thermoplastic synthetic fiber (not shown). 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. It is preferably contained in an amount of 30% by mass or more, and the upper limit value is preferably 50% by mass or less.

When the hydrophilic fiber layer 43 contains a hydrophilic thermoplastic synthetic fiber (not shown), the hydrophilic thermoplastic synthetic fiber (not shown) includes the thermoplastic synthetic fiber 44 which is the main component of the synthetic fiber layer 42 described above. It is possible to use a fiber made of the same material as the above, to which a hydrophilic oil agent usually used for a constituent fiber such as a non-woven fabric is added. 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 constitutes the synthetic fiber layer 42. It is preferable that the hydrophilicity of the thermoplastic synthetic fiber 44 is higher than that of the thermoplastic synthetic fiber 44.

The pattern of the shape of the consolidation portion 46 is a pattern formed from a circle or a polygon in a dot shape, a strip shape, or a combination thereof, and is arranged continuously or dispersedly in the vertical direction X. As shown in 1 and FIG. 3, when the absorber 4 is viewed in a plan view, the pattern of the consolidation portion 46 is a dot-shaped pattern formed from a circle. Then, in the diaper 1, such circular compacted portions 46 are dispersedly arranged in the vertical direction X. The area of the consolidated portion 46 (in diaper 1 the total area of the plurality of consolidated portions 46 arranged on the two non-stacked portions 48) (S2) shall be appropriately changed according to the area of the non-stacked portion 48. Can be done.

When the diaper 1 is viewed in a plan view as shown in FIGS. 1 and 3, the ratio of the area (S2) of the consolidated portion 46 to the area (S1) of the non-stacked portion 48 ((S2 / S1) × 100) is From the viewpoint of achieving both the stable bonding strength of the consolidated portion 46 and the softness of the consolidated portion 46, it is 10% or more, preferably 20% or more, further preferably 25% or more, and 80%. It is less than or equal to 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 consolidation portion 46 means the area of the portion surrounded by the outer circumference of the consolidation portion 46 in a plan view of the consolidation portion 46.

In each of the consolidated portions 46 of the non-skin side core wrap sheet 48, as shown in FIG. 5, the hydrophilic fiber layer 43 of the skin side core wrap sheet 41U and the hydrophilic fiber layer 43 of the non-skin side core wrap sheet 41D are in contact with each other. ing. Then, in the skin-side core wrap sheet 41U, the non-thermoplastic hydrophilic fibers 45 constituting the hydrophilic fiber layer 43 pass through the synthetic fiber layer 42 on the outer surface side and are exposed on the skin-facing surface side of the absorber 4. .. Further, in the non-skin side core wrap sheet 41D, the non-thermoplastic hydrophilic fibers 45 constituting the hydrophilic fiber layer 43 pass through the synthetic fiber layer 42 on the outer surface side and are exposed on the non-skin facing surface side of the absorber 4. ing. Preferably, the compacted portion 46 is a portion of the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D that is compacted in the thickness direction. , The thermoplastic synthetic fiber 44 is carried out by embossing (squeezing) with a melting promoting means for promoting melting. When squeezing the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D with such a melting promoting means, it may be performed from either the skin-side core wrap sheet 41U or the non-skin-side core wrap sheet 41D. Often, both sheets 41U and 41D may be squeezed, 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 It is preferable to apply the pressing to the synthetic fiber layer 42 on the outer surface side. In the compacted portion 46, the interfiber gap is narrower or the interfiber gap is substantially smaller than that of the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D other than the compacted portion 46 (non-consolidated portion). It is a high-density portion that does not exist, and the non-consolidated portion is a low-density portion having a wider interfiber gap than the compacted portion 46.

In the diaper 1, as described above, in each of the compacted portions 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 on the skin-facing surface side of the absorber 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 synthetic fiber layer 42 on the outer surface side and are exposed on the non-skin facing surface side of the absorber 4. There is. Then, the hydrophilic fiber layer 43 of the skin-side core wrap sheet 41U and the hydrophilic fiber layer 43 of the non-skin-side core wrap sheet 41D are in contact with each other. Therefore, the hydrophilic fiber 45 exposed on the skin facing surface side of the absorber 4 and the hydrophilic fiber 45 exposed on the non-skin facing surface side of the absorber 4 are the hydrophilic fiber layer of the skin side core wrap sheet 41U. It is connected via the hydrophilic fiber layer 43 of 43 and the non-skin side core wrap sheet 41D. In each compacted portion 46, whether or not 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 on the skin facing surface side of the absorber 4, or is 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 on the non-skin facing surface side of the absorber 4 is confirmed in the thickness direction of the compacted portion 46. It can be carried out by microscopic observation of a cross section along (Z direction), and specifically, it can be carried out by the following method.

<Method of confirming that the non-thermoplastic hydrophilic fiber 45 passes through the synthetic fiber layer 42 and is exposed on the skin-facing surface side or the non-skin-facing surface side of the absorber 4 in the consolidated portion>
Immerse the sheet to be evaluated (core wrap sheet 41) in a 0.5 mass% blue aqueous solution (Edible Blue No. 1 of Aizen food dye manufactured by Daiwa Kasei), allow it to stand for 3 minutes, then remove the sheet from the aqueous solution and take it out. The sheet is placed on a pre-laid paper (Kim Towel, manufactured by Nippon Paper Crecia Co., Ltd.) with the skin-facing side facing down, and a load of 3 kPa is applied from above the sheet to dehydrate it over 1 minute. By this operation, the hydrophilic fibers among the constituent fibers of the evaluation target sheet are dyed.
The consolidated portion 46 to be evaluated of the dyed sheet thus obtained is cut along the lateral direction Y of the diaper 1 using a single-edged razor manufactured by Feather, and the cut surface thereof is cut with a microscope (VHX-1000 manufactured by KEYENCE). ) Is observed at a magnification of 200 to 500 times, and the non-thermoplastic hydrophilic fiber 45 is exposed on the skin-facing surface side of the absorber 4 or the non-skin-facing surface side of the absorber 4 in the compacted portion 46. Check if it is done. In the compacted portion 46, since the non-thermoplastic hydrophilic fiber 45 is dyed, it is determined whether or not the consolidated portion 46 is exposed on the skin-facing surface side of the absorber 4 or the non-skin facing surface side of the absorber 4. Is easy.

As described above, the compacted portion 46 is typically formed by embossing with heat, ultrasonic waves, or the like, and the synthetic fiber layer of the skin-side core wrap sheet 41U of the compacted portion 46 formed by such embossing. In the synthetic fiber layer 42 of the core wrap sheet 41D on the non-skin side and the non-skin side core wrap sheet 41D, the thermoplastic synthetic fiber 44, which is the main component of the synthetic fiber layer 42, is softened and melted by heat and ultrasonic waves during embossing, so that the original form of the fiber aggregate is changed. It has been lost and has been made into a film. A part of the non-thermoplastic hydrophilic fiber 45, which is the main component of the hydrophilic fiber layer 43, enters the film-formed synthetic fiber layer 42 of the compacted portion 46 (the fiber form is lost), and is an absorber. It is exposed on the skin-facing surface side of 4 or the non-skin-facing surface side of the absorber 4. That is, in the compacted portion 46, one or more exposed portions of the hydrophilic fibers 45 are present in the synthetic fiber layer 42 formed into a film with the skin-facing surface side of the absorber 4 viewed in a plan view. The hydrophilic fibers 45 forming the exposed portion are continuous from the skin-facing surface side to the non-skin-facing surface side of the skin-side core wrap sheet 41U. Further, in the compacted 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 non-skin facing surface side of the absorber 4 is viewed in a plan view. The non-thermoplastic hydrophilic fiber 45 forming 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 absorber 4 is covered with the skin side core wrap sheet 41U and the non-skin side core wrap sheet 41D. A hydrophilic fiber layer 43 in which a skin-side core wrap sheet 41U and a non-skin-side core wrap sheet 41D are arranged on the inner surface side in contact with the absorbent core 40 and are mainly composed of non-thermoplastic hydrophilic fibers 45. And a laminated sheet having a synthetic fiber layer 42 arranged on the outer surface side in contact with the hydrophilic fiber layer 43 and mainly composed of the thermoplastic synthetic fiber 44. Further, in the non-stacked fiber 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. In this way, in the compacted portion 46, the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D that cover the absorbent core 40 are integrated with each other, so that the shape-retaining property of the absorbent body 4 during wearing is improved. It is excellent, the absorber 4 is not easily broken during wearing, and the usability is improved. In particular, since the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D contain the synthetic fiber layer 42 made of non-woven fabric, the absorber 4 is more difficult to break during wearing. Further, when the body fluid absorbed during wearing in the non-stacked fiber portion 48 of the absorbent core 40 is taken into the absorbent body 4 from the periphery of the consolidated portion 46 and the compacted portion 46, the skin side core wrap sheet 41U and the non-consolidated portion 46 and the non-consolidated portion 46 are taken in. It is easily transmitted in the surface direction through the hydrophilic fiber layer 43 that abuts on the absorbent core 40, which constitutes the skin-side core wrap sheet 41D, the liquid diffusivity 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 body liquid once absorbed by the absorber 4 is the hydrophilic fiber layer 43. The synthetic fiber layer 42 arranged on the outer surface side in contact with the wearer does not easily return to the skin side of the wearer, and the usability of the diaper 1 is improved.

Further, in the diaper 1, in each of the compacted portions 46, as shown in FIG. 5, the non-thermoplastic hydrophilic fibers 45 of the skin-side core wrap sheet 41U pass through the synthetic fiber layer 42 and the absorber 4 is on the skin-facing surface side. The non-thermoplastic hydrophilic fibers 45 of the non-skin side core wrap sheet 41D pass through the synthetic fiber layer 42 and are exposed to the non-skin facing surface side of the absorber 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 of the compacted portions 46, the hydrophilic fibers 45 exposed on the skin-facing surface side of the absorber 4 easily function as a fluid passage (liquid passage trigger) of the body fluid, and the absorption is located in the non-separated fiber portion 48. The body fluid on the skin-facing surface of the body 4 diffuses into the hydrophilic fiber layer 43 through the compaction portion 46 (exposed portion of the hydrophilic fiber 45) and is easily taken into the absorbent core 40. In particular, when the non-stacked portion 48 of the absorbent core 40 is arranged at least in the inseam 1M, the non-stacked portion 48 of the absorbent core 40 is quickly placed in the absorbent core 40 via each of the consolidated portions 46 arranged in the non-stacked fiber portion 48. It becomes easy to be taken in.

From the viewpoint of further exerting the above-mentioned effects, the diaper 1 preferably has one or more of the following configurations.

When 10 are arbitrarily selected from the plurality of compacted portions 46 existing at the positions of the non-folded fiber portions 48 of the absorbent core 40, in the 10 consolidated portions 46, the side of the absorber 4 facing the skin, in other words. For example, the non-thermoplastic hydrophilic fiber 45 (consolidated 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. The ratio of "parts"), that is, the value calculated by "(the number of exposed and compacted parts of the hydrophilic part / 10) x 100" is preferably 40% or more, and more preferably 50% or more.
Whether or not a certain consolidation portion is the hydrophilic portion exposed consolidation portion is confirmed by the following method. That is, with respect to 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 compacted portion, and the fibers of such a consolidated portion If the exposure can be confirmed at even one place, the compacted portion is assumed to be the hydrophilic portion exposed and compacted portion.
Further, the length of the evaluation sheet in the compacted portion 46 in the longitudinal direction (when the planar view shape of the compacted portion 46 is an anisotropic shape such as a rectangular shape) or the length in the vertical direction X (the planar view shape of the compacted portion 46 is a circle). (In the case of an isotropic shape such as a shape) and the lateral length of the evaluation sheet (when the plan view shape of the compaction portion 46 is an anisotropic shape) or the length in the lateral direction Y (when the plan view shape of the compaction portion 46 is When the isotropic shape) exceeds 2 mm, the range of the longitudinal length 2 mm of the evaluation sheet × the lateral length 2 mm of the evaluation sheet in the compaction portion 46 is treated as one compaction portion, and the hydrophilic fibers 45 are exposed. And the ratio occupied by the exposed and compacted hydrophilic part will be calculated.

In the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D, the synthetic fiber layer 42 has a lower hydrophilicity than the hydrophilic fiber layer 43 in the portions other than the compacted portion 46, in other words, hydrophilic. The sex fiber layer 43 preferably has a higher hydrophilicity than the synthetic fiber layer 42. The hydrophilicity of the sheet (layer) referred to here is evaluated by the water droplet disappearance rate measured by the following method. The smaller the value of the water droplet disappearance rate, the lower the hydrophilicity, and the larger the value of the water droplet disappearance rate, 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 established.

<Measurement method of water droplet disappearance rate>
The sheet to be evaluated (for example, the skin-side core wrap sheet 41U or its synthetic fiber layer 42 or the hydrophilic fiber layer 43) is fixed in the air so that the surface becomes horizontal, and is placed at any 20 positions on the upper surface of the sheet. Water droplets (1 drop 2 μl) of physiological saline (saline solution having a concentration of 0.9% by mass) are dropped using a microsyringe. If the hydrophilicity of the sheet to be evaluated is high, the water droplets are immediately absorbed by the sheet and disappear after dropping, and if the hydrophilicity of the sheet is low, the water droplets are not absorbed and remain on the upper surface of the sheet. The disappearance of the water droplets is determined by visually observing the upper surface of the sheet 10 seconds after the water droplets are dropped. The water droplet disappearance rate (%) is obtained by calculating the ratio of the water droplet disappearance points within 10 seconds out of the measurement at 20 points.

The ratio of the water droplet disappearance rate of the portion of the synthetic fiber layer 42 other than the consolidated portion 46 to the water droplet disappearance rate of the portion of the hydrophilic fiber layer 43 other than the consolidated portion 46 is preferably smaller in the former than in the latter.
The water droplet disappearance rate of the portion 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 portion 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 performed on the types of the constituent fibers (thermoplastic synthetic fiber 44) of the synthetic fiber layer 42 and the constituent fibers (hydrophilic fiber 45) of the hydrophilic fiber layer 43, and the hydrophobizing agent (hydrophilic fiber 45). It can be carried out mainly by using a synthetic fiber layer 42) or a hydrophilizing agent (mainly for the hydrophilic fiber layer 43).

The absorbent core 40 constituting the absorbent body 4 is composed of the water-absorbent polymer and the cellulosic fiber in the diaper 1, and the content mass ratio of the water-absorbent polymer and the cellulosic fiber is as the former: the latter. It 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 the diffusion of body fluids 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 non-thermoplastic, which are the main components of the hydrophilic fiber layer 43, respectively. 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 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, further preferably 2000 mm ² or less. be.

In the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D, it is preferable that the fiber diameters of the thermoplastic synthetic fiber 44 and the non-thermoplastic hydrophilic fiber 45 are both small, respectively. Since the fiber diameter of the thermoplastic synthetic fiber 44, which is the main component of the synthetic fiber layer 42, is relatively small, the fiber 44 is more likely to be melted or deformed due to compaction, and the absorber 4 is on the side facing the skin or not. The exposure of the hydrophilic fibers 45 on the side facing the skin is more likely to occur, and the fiber diameter of the hydrophilic fibers 45, which is the main component of the hydrophilic fiber layer 43, is relatively small, so that the fibers 45 are exposed. 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, still more preferably 2.2 dtex or less. The thickness of the hydrophilic fiber 45 is preferably 50 μm or less, more preferably 30 μm or less, respectively, in the case of a circular shape, the diameter, and in the case of an elliptical / flat shape, the length of the major axis thereof.

Further, with respect to 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 absorber 4 is exposed on the skin-facing surface side or the non-skin-facing surface side. It is preferable from the viewpoint of more reliable realization.
Further, a viewpoint of ensuring continuity from the exposed portion of the absorber 4 on the skin-facing surface side or the non-skin-facing surface side to the synthetic fiber layer 42 so that the function as a liquid guide can be more reliably performed. 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, further preferably 15 mm or less.

Further, the basis weight of the synthetic fiber layer 42 is preferably relatively small. When the basis weight of the synthetic fiber layer 42 becomes excessive, the film formation of the synthetic fiber layer 42 (thermoplastic synthetic fiber 44) in the compacted portion 46 is excessively promoted, and as a result, the compacted portion 46 faces the skin or is not opposed to the skin. The surface side is completely blocked by the film-formed synthetic fiber layer 42, 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 absorber 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, and 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 a separate material from the raw fabric sheet of the synthetic fiber layer 42 (typically, a non-woven fabric mainly composed of the thermoplastic synthetic fiber 44). It may be a laminated body in which the raw fabric sheet of the hydrophilic fiber layer 43 (typically, paper mainly composed of non-thermoplastic hydrophilic fibers 45) is laminated. The above-mentioned absorber 4 covers the absorbent core 40 with the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D made of such a laminated body, and inside the non-synthetic fiber portion 48 of the absorbent core 40. In the above, the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D made of the laminated body are overlapped with each other, and a melting promoting means for promoting melting of the thermoplastic synthetic fiber 44 such as heat and ultrasonic waves is provided. It can be manufactured by embossing (squeezing). By this embossing, the thermoplastic synthetic fiber 44 in the raw fabric sheet of the synthetic fiber layer 42 on the outer surface side is melted, deformed and formed into a film, and the hydrophilic fiber in the raw fabric sheet of the hydrophilic fiber layer 43 on the inner surface side is formed. 45 is easily exposed to the surface side of the filmed portion. In the absorber 4 manufactured by such a method, the portion where the embossed portion is applied becomes the compacted portion 46, and the synthetic fiber layer 42 and the hydrophilic fiber layer 43 are joined and integrated via the compacted portion 46. There is. In this way, when the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D formed of a laminate composed of two raw fabric sheets are used, the basis weight of each hydrophilic fiber layer 43 is as paper. From the viewpoint of maintaining the morphology, 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, still 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 use a raw sheet of the synthetic fiber layer 42, a paper slurry containing the non-thermoplastic hydrophilic fiber 45, and a papermaking net. It may be a sheet produced by a known wet papermaking method. Specifically, first, the raw sheet of the synthetic fiber layer 42 is placed on the papermaking net. Next, a paper slurry containing the hydrophilic fibers 45 is poured into the raw sheet on the papermaking net. The water in the poured paper material slurry sequentially permeates the raw fabric sheet and the papermaking net and flows down from below the papermaking net, and the hydrophilic fibers 45 in the paper material slurry are the constituent fibers (heat) of the raw fabric sheet. It is entangled with the plastic synthetic fibers 44) and stays in the raw sheet, whereby a wet sheet having a two-layer structure containing the hydrophilic fibers 45 and the thermoplastic synthetic fibers 44 is formed on the papermaking net. A suction means may be arranged on the opposite side of the papermaking net from the raw fabric sheet, and the suction means may promote dehydration of the raw fabric sheet. Then, by drying this wet sheet by various drying means adopted in the wet papermaking method, the target skin-side core wrap sheet 41U and non-skin-side core wrap sheet 41D are manufactured. The above-mentioned absorber 4 covers the absorbent core 40 with the skin-side core wrap sheet 41U and the non-skin-side core wrap sheet 41D produced in this manner, and in the non-synthetic fiber portion 48 of the absorbent core 40. , Skin-side core wrap sheet 41U and non-skin-side core wrap sheet 41D are overlapped and embossed (squeezed) with a melting promoting means for promoting melting of the thermoplastic synthetic fiber 44 such as heat and ultrasonic waves. It can be manufactured by applying. In the absorber 4 manufactured by such a method, the portion provided with the embossed portion becomes the compacted portion 46, and the synthetic fiber layer 42 and the hydrophilic fiber layer 43 are integrated with the compacted portion 46 in addition to the compacted portion 46. , Both fibers 44, 45 are also entangled.

In the skin-side core wrap sheet 41U manufactured by such a wet papermaking method, usually, the surface side of the raw fabric sheet facing the papermaking net, the so-called wire surface side (the side opposite to the supply side of the paper slurry). Since the non-thermoplastic hydrophilic fibers 45 are unevenly distributed in, the wire surface side becomes the hydrophilic fiber layer 43. The distribution state of the hydrophilic fibers 45 on the skin-side core wrap sheet 41U can be adjusted by appropriately adjusting the pore diameter and pitch of the dehydration holes of the papermaking net. In particular, when the paper slurry containing the hydrophilic fibers 45 is poured into the raw fabric sheet and then a high-pressure water stream is sprayed onto the felt surface side of the raw fabric sheet, the compacted portion 46 formed by the subsequent embossing is formed. This 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 absorber 4.

Although the present invention has been described above based on the embodiment, the present invention can be appropriately modified without being limited to the embodiment.

For example, in the diaper 1, the pattern of the consolidation portion 46 is a dot-shaped pattern formed from a circle in a plan view as shown in FIGS. 1 and 3, but as shown in FIG. 6A, It is formed by a dot-shaped pattern formed from a polygon, and may be a pattern dispersedly arranged in the vertical direction X. Further, as shown in FIGS. 6 (b) and 6 (c), the consolidation portions 46 are formed in a pattern formed from a linear shape, and may be a pattern dispersedly arranged in the vertical direction X. .. Preferably, the linear compacted portion 46 shown in FIG. 6B is formed so as to extend parallel to the lateral direction Y from one side edge along the vertical direction X of each non-stacked fiber portion 48 toward the other side edge. The non-stacked fiber portions 48 are arranged at regular intervals in the vertical direction X, and are dispersedly arranged in the vertical direction X. also,
Preferably, the linear compaction portion 46 shown in FIG. 6C is a virtual line extending parallel to the lateral direction Y from one side edge along the vertical direction X of each non-stacking portion 48 toward the other side edge. It is formed so as to intersect with each other, is arranged at regular intervals in the vertical direction X of the non-stacked fiber portion 48, and is dispersedly arranged in the vertical direction X. Further, as shown in FIG. 6D, the consolidated portion 46 is formed in a pattern formed from a linear shape, and the linear compacted portion 46 is formed from one end of each non-stacked portion 48 in the vertical direction X. It is formed so as to extend parallel to the vertical direction X toward the other end, and may be arranged at regular intervals in the horizontal direction Y of the non-stacked fiber portion 48. Further, the pattern of the consolidation portion 46 may be a pattern in which dots or bands formed from a circle or a polygon are 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 absorbent core 40 is not. 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 to wrap the absorbent core 40. 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 in terms of its composition and material. good.

Further, from the viewpoint of improving absorbency and leakage resistance, liquid permeability made of paper or various non-woven fabrics, which is also called a sublayer or the like, is formed between the surface sheet 2 and the absorber 4 (skin side core wrap sheet 41U). Sheets may be intervened. From the same viewpoint, a groove formed by integrally compacting the surface sheet 2 and the absorber 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 the deployable disposable diaper, but includes a wide range of articles used for absorbing 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, etc. are also included.

1 Deployable disposable diaper (absorbent article)
2 Front sheet 3 Back sheet 4 Absorber 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 Sex fiber 46 Closed part 48 Non-stacked part 1F Ventral side 1M Crotch part 1R Dorsal side X Vertical direction Y Lateral direction

Claims (8)

It comprises an absorber having a liquid-retaining absorbent core and a core wrap sheet covering the absorbent core, and extends from the ventral side of the wearer to the dorsal side through the crotch portion in the vertical direction and laterally orthogonal to the vertical direction. An absorbent article having a direction and a crotch portion arranged in the crotch portion, and a ventral side portion and a dorsal portion extending in front of and behind the crotch portion.
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 that covers the skin-facing surface of the absorbent core and a non-skin-side core wrap sheet that covers the non-skin-facing surface of the absorbent core.
The skin-side core wrap sheet and the non-skin-side core wrap sheet are each composed of a hydrophilic fiber layer arranged on the inner surface side in contact with the absorbent core and mainly composed of non-thermoplastic hydrophilic fibers. It is a laminated sheet having a synthetic fiber layer arranged on the outer surface side in contact with the hydrophilic fiber layer and mainly composed of thermoplastic synthetic fibers.
In the non-stacked portion of the absorbent core, the skin-side core wrap sheet and the non-skin-side core wrap sheet are integrated with each other via a compaction portion .
In the compacted portion of the non-skin-side core wrap sheet, the hydrophilic fiber layer of the skin-side core wrap sheet and the hydrophilic fiber layer of the non-skin-side core wrap sheet are in contact with each other.
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 . , Absorbent articles. It comprises an absorber having a liquid-retaining absorbent core and a core wrap sheet covering the absorbent core, and extends from the ventral side of the wearer to the dorsal side through the crotch portion in the vertical direction and laterally orthogonal to the vertical direction. An absorbent article having a direction and a crotch portion arranged in the crotch portion, and a ventral side portion and a dorsal portion extending in front of and behind the crotch portion.
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 that covers the skin-facing surface of the absorbent core and a non-skin-side core wrap sheet that covers the non-skin-facing surface of the absorbent core.
The skin-side core wrap sheet and the non-skin-side core wrap sheet are each composed of a hydrophilic fiber layer arranged on the inner surface side in contact with the absorbent core and mainly composed of non-thermoplastic hydrophilic fibers. It is a laminated sheet having a synthetic fiber layer arranged on the outer surface side in contact with the hydrophilic fiber layer and mainly composed of thermoplastic synthetic fibers.
The skin-side core wrap sheet and the hydrophilic fiber layer of the non-skin-side core wrap sheet contain hydrophilic thermoplastic synthetic fibers in the non-thermoplastic hydrophilic fibers constituting the same.
In the non-stacked portion of the absorbent core, the skin-side core wrap sheet and the non-skin-side core wrap sheet are integrated with each other via a compaction portion .
In the compacted portion of the non-skin-side core wrap sheet, 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. An absorbent article in which the fibers are fused, integrated and joined. It comprises an absorber having a liquid-retaining absorbent core and a core wrap sheet covering the absorbent core, and extends from the ventral side of the wearer to the dorsal side through the crotch portion in the vertical direction and laterally orthogonal to the vertical direction. An absorbent article having a direction and a crotch portion arranged in the crotch portion, and a ventral side portion and a dorsal portion extending in front of and behind the crotch portion.
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 that covers the skin-facing surface of the absorbent core and a non-skin-side core wrap sheet that covers the non-skin-facing surface of the absorbent core.
The skin-side core wrap sheet and the non-skin-side core wrap sheet are each composed of a hydrophilic fiber layer arranged on the inner surface side in contact with the absorbent core and mainly composed of non-thermoplastic hydrophilic fibers. It is a laminated sheet having a synthetic fiber layer arranged on the outer surface side in contact with the hydrophilic fiber layer and mainly composed of thermoplastic synthetic fibers.
In each of the skin-side core wrap sheet and the non-skin-side core wrap sheet,
The hydrophilicity of the thermoplastic synthetic fiber constituting the synthetic fiber layer is lower than the hydrophilicity of the non-thermoplastic hydrophilic fiber constituting the hydrophilic fiber layer.
In the non-stacked portion of the absorbent core, the skin-side core wrap sheet and the non-skin-side core wrap sheet are integrated with each other via a compaction portion. The absorbent article according to any one of claims 1 to 3 , wherein the non-stacked portion is arranged at least in the crotch portion of the absorbent core and extends in the vertical direction. When the absorber is viewed in a plan view, the ratio of the area of the consolidated portion to the area of the non-stacked portion is 10% or more and 80% or less, and the shape pattern of the consolidated portion is circular or polygonal. The absorbent article according to any one of claims 1 to 4 , which is formed in a dot shape, a strip shape, or a pattern obtained by combining these, and is arranged continuously or dispersedly in the vertical direction. The skin-side core wrap sheet and the non-skin-side core wrap sheet are each composed of a spunbonded non-woven fabric or a spunbond-melt blown-spunbonded non-woven fabric, and the average interfiber distance between the fibers constituting the non-woven fabric is 10 μm. The absorbent article according to any one of claims 1 to 5 , which is 200 μm or less. Claims 1 to 6 wherein the skin-side core wrap sheet and the hydrophilic fiber layer of the non-skin-side core wrap sheet contain pulp, cotton, or rayon in the non-thermoplastic hydrophilic fibers constituting the core wrap sheet. The absorbent article according to any one of the above. The absorbent core contains a water-absorbent polymer and contains
The absorbent article according to any one of claims 1 to 7 , wherein the content mass ratio of the water-absorbent polymer and the cellulosic fiber is the former: the latter = 1: 1.5 to 1: 0.

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