RU2765116C1 - Disposable diaper type underpants - Google Patents

Abstract

FIELD: personal hygiene products.

SUBSTANCE: disposable diaper (1) has a front zone (F), a rear zone (M) and a perineal zone (R) and includes an absorbent node (2) and an outer covering element (3) located on the side of the surface of the absorbent node (2) not facing the skin. The outer covering element (3) includes at least an outer sheet (31) of non-woven material forming a surface not facing the skin, and an inner sheet (31) of non-woven material forming a surface facing the skin. Each of the front zone (F) and rear zone (R) has a protruding part in which at least one of the outer sheets (31) of non-woven fabric and the inner sheet (32) of non-woven material protrudes outward from the edge of the waist opening. The protruding parts are bent to the surface facing the skin to form bent parts (35) covering, respectively, the front end part and the rear end part of the absorbent node (2). In the bent parts (35), the sheet of non-woven material forming a surface that is closest to the skin and represents the surface of the part covering the front end part, and the sheet of non-woven material forming a surface that is closest to the skin and represents the surface of the part covering the rear end part have different properties.

EFFECT: expansion of the range of personal hygiene products.

16 cl, 7 dwg

Description

The field of technology to which the invention relates

[0001]

The present invention relates to a pull-on disposable diaper.

Prior Art

[0002]

A pull-on disposable diaper typically includes an absorbent assembly including an absorbent member and an outer cover located on a non-skin side of the absorbent assembly, and both side edges of the outer cover member in a front portion which is a portion corresponding to front part of the body are attached to both side edges of the outer cover in the back part, which is the part corresponding to the back part of the body, whereby two side seams, a waist opening and two leg openings are formed. In recent years, in order to improve the wearing comfort of disposable diapers, various improvements in the configuration of the skin-facing surface in the area of the waist opening have been analyzed.

[0003]

For example, Patent Literature 1 discloses a pull-on absorbent article in which, in order to improve breathability, the longitudinally terminating side of the skin-facing surface of the absorbent assembly portion is covered by a folded portion of the inner sheet of the outer cover, with the folded portion folded onto the absorbent assembly. In addition, Patent Literature 2 and 3 discloses pull-on absorbent articles in which, in order to improve wearing comfort and flexibility, the skin-facing surface side of the waist opening area, the skin-facing surface side of the absorbent assembly portion ending in the longitudinal direction , is covered by a sheet which is separate from the outer cover.

Link List

Patent Literature

[0004]

Patent Literature 1: JP 2009-72532A

Patent Literature 2: JP 2001-314441A

Patent Literature 3: US 2013110070A1

The essence of the invention

[0005]

The present invention relates to a pull-on disposable diaper having a front area, a back area, and a crotch area located between the front and back areas,

wherein the pull-on disposable diaper includes an absorbent assembly located in a zone extending from the front zone to the back zone, and an outer cover element located on the side of the surface of the absorbent node that is not facing the skin.

The outer covering element includes an outer sheet of non-woven material forming a surface of the outer covering element not facing the skin, an inner sheet of non-woven material forming the surface of the outer covering element facing the skin, and an elastic element located between the outer and inner sheets of non-woven material.

The outer cover has, in each of the front area and back area, a protrusion in which at least one of the outer nonwoven fabric sheet and the inner nonwoven fabric sheet protrudes outward from the edge of the waist opening, and the protrusions are folded onto a skin-facing surface, to form folded portions covering, respectively, the front end portion and the rear end portion of the absorbent assembly.

In the folded portions, a nonwoven fabric sheet forming a surface that is closest to the skin and is the surface of the front end covering portion, and a nonwoven fabric sheet forming a surface that is closest to the skin and is the surface of the rear end covering part, have different properties.

[0006]

In addition, the present invention relates to a pull-on disposable diaper having a front area, a back area, and a crotch area located between the front and back areas,

wherein the pull-on disposable diaper includes an absorbent assembly located in a zone extending from the front zone to the back zone, and an outer cover element located on the side of the surface of the absorbent node that is not facing the skin.

The outer cover includes an outer sheet of nonwoven fabric forming a non-skin facing surface of the outer cover and an inner sheet of nonwoven fabric forming a skin facing surface of the outer cover.

The outer cover has, in each of the front area and back area, a protrusion in which at least one of the outer nonwoven fabric sheet and the inner nonwoven fabric sheet protrudes outward from the edge of the waist opening, and the protrusions are folded onto a skin-facing surface, to form folded portions covering, respectively, the front end portion and the rear end portion of the absorbent assembly.

In the folded portions, one of a sheet of nonwoven fabric forming a surface that is closest to the skin and is the surface of the part covering the front end part, and a sheet of nonwoven fabric forming a surface that is closest to the skin and is the surface of the part covering the back end part is an elastic nonwoven fabric and the other sheet of nonwoven fabric is a non-elastic nonwoven fabric.

[0007]

In addition, the present invention relates to a method for manufacturing the above-described pull-on disposable diaper, the method comprising:

overlaying a continuous outer sheet of nonwoven material and a continuous inner sheet of nonwoven material, which move in one direction, one on top of the other to form a continuous outer cover member thereby;

arranging the absorbent nodes on the side of the continuous outer cover that is the side of the continuous inner nonwoven sheet at intervals in the direction of movement so that the longitudinal direction of the absorbent nodes corresponds to a direction perpendicular to the direction of movement;

folding both side regions of the continuous outer cover, defined in its width direction, onto absorbent nodes;

folding the continuous outer cover with the absorbent nodes in half at the part central in the width direction, and joining the parts of the continuous outer cover that become opposite to each other as a result of the fold in half, at the positions between the absorbent nodes adjacent to each other in the direction of movement, for forming connected zones thereby and hence forming a continuous disposable diaper; and

then cutting the continuous disposable diaper at the joined zones along the width direction of the continuous disposable diaper.

In the step of folding both side zones of the continuous outer cover, the continuous outer cover is folded so that the folded portion of one of the side zones of the continuous outer cover covers the end zones of the absorbent units from the side of one end defined in the longitudinal direction, and the folded portion of the other side zone of the continuous of the outer cover covering the end zones of the absorbent nodes from the side of the other end, defined in the longitudinal direction, and that the part that is located in the folded part of this one side zone and covers the end zones of the absorbent nodes from the side of this one end, defined in the longitudinal direction, and the part , which is in the folded portion of the other side region and covers the end regions of the absorbent units from the side of one longitudinal end, were formed by nonwoven fabric sheets having different properties.

[0008]

In addition, the present invention relates to a method for manufacturing the above-described pull-on disposable diaper, the method comprising:

overlaying a continuous outer sheet of nonwoven material and a continuous inner sheet of nonwoven material, which move in one direction, one on top of the other to form a continuous outer cover member thereby;

cutting the continuous outer cover in the direction of movement in a part central in its width direction, to thereby form two parts of the outer cover obtained by cutting;

placement of the absorbent knots on the side of the cut portions of the outer cover that is the side of the continuous inner sheet of nonwoven material, at intervals in the direction of travel so that the longitudinal direction of the absorbent knots corresponds to a direction perpendicular to the direction of travel and so that the absorbent knots connect the two parts obtained by cutting;

bending the outer, in the width direction, side regions of the respective cut portions of the outer cover into absorbent units;

folding the cut portions of the outer cover with the absorbent assemblies in half at a portion of each absorbent assembly centered in the width direction, and joining the cut portions of the outer cover, which become opposed to each other as a result of the fold in half, to each other at the locations between absorbent nodes adjacent to each other in the direction of movement, to form connected areas through this and, therefore, the formation of a continuous disposable diaper; and

then cutting the continuous disposable diaper at the joined zones along the width direction of the continuous disposable diaper.

In the step of bending the outer side regions of the respective cut portions of the outer cover, the cut portions of the outer cover are folded so that the folded portion of the width direction outer side portion of one of the cut portions of the outer cover covers the end regions of the absorbent nodes from the side of one end defined in the longitudinal direction, and the bent part of the outer in the width direction, the side zone of the other part of the outer covering element obtained by cutting, covers the end zones of the absorbent nodes from the side of the other end defined in the longitudinal direction, and that the part that is located in the folded part of this one outer side zone and covers the end zones of the absorbent nodes from the side of this one end, defined in the longitudinal direction, and the part that is located in the folded part of the other outer side zone and covers the end zones of the absorbent nodes with o sides of the other end defined in the longitudinal direction were formed by nonwoven fabric sheets having different properties.

Brief description of the drawings

[0009]

[Fig. 1] Fig. 1 is a perspective view schematically showing an embodiment of a pull-on disposable diaper in its natural state.

[Fig. 2] Fig. 2 is an expanded plan view schematically showing the skin-facing surface side (inner surface side) of the disposable diaper shown in Fig. 1 in its flat-folded, uncontracted state.

[Fig. 3] Fig. 3(a) is a schematic sectional view showing a folded portion located on the front side of the disposable diaper shown in Fig. 1, and Fig. 3(b) is a schematic sectional view showing a folded portion located on the back side of the disposable diaper shown in Fig.1.

[Fig. 4] Fig. 4(a) is a schematic sectional view showing the folded portion located on the front side of another embodiment of the pull-on disposable diaper, and Fig. 4(b) is a schematic sectional view showing the folded portion. located on the back side of this other embodiment of the pull-on disposable diaper.

[Fig. 5] Fig. 5 is a perspective view schematically showing another embodiment of a pull-on disposable diaper in its natural state.

[Fig. 6] Fig. 6 is a schematic view schematically showing an embodiment of a manufacturing equipment for use in a method for manufacturing a pull-on disposable diaper.

[Fig. 7] Fig. 7 is a schematic view schematically showing an embodiment of another manufacturing equipment for use in a method for manufacturing a pull-on disposable diaper.

Description of Embodiments

[0010]

The absorbent article disclosed in Patent Literature 1 can be improved to perform other wearing comfort functions other than breathability. The absorbent articles disclosed in Patent Literature 2 and 3 perform the functions of improving wearing comfort by additionally attaching a sheet separate from the outer cover, but these absorbent articles have a high rigidity, and therefore there is room for improvement for providing increased wearing comfort while providing a given stiffness. In addition, the changes that are necessary to additionally attach a single sheet are costly under actual production conditions.

[0011]

Therefore, the present invention relates to a put-on disposable diaper that can overcome the above-described shortcomings of the prior art, and to a method for manufacturing a put-on disposable diaper.

[0012]

Hereinafter, the disposable diaper of the present invention will be described based on the preferred embodiments thereof. 1-3 show an embodiment of the pull-on disposable diaper of the present invention. As shown in Figs. 1-3, the diaper 1 has a front area F provided on the ventral side of the wearer when the diaper 1 is worn, a rear area R provided on the dorsal side of the wearer, and a crotch area M located between these two areas. These zones extend continuously in the direction from the front side to the rear side of the carrier. The diaper 1 has a longitudinal direction X, which extends from the ventral side to the dorsal side of the wearer through the crotch portion, and a lateral direction Y, which is perpendicular to the longitudinal direction X.

[0013]

As shown in FIG. 1, the diaper 1 includes an absorbent assembly 2 including an absorbent member 23 configured to absorb and retain exudates, and an outer cover member 3 disposed on a non-skin side of the absorbent assembly 2. In the diaper 1, both sides of the outer cover 3 located on the front side are attached to both sides of the outer cover 3 located on the back side by a connecting means such as adhesive, heat sealing or ultrasonic welding, and thus two side seams S, a waist opening WH into which the wearer's waist should enter, and two leg openings LH into which the wearer's legs should be inserted.

[0014]

When referring to a disposable diaper or a component thereof (e.g., an absorbent assembly) herein, the term "skin-facing surface" refers to a surface that is intended to face the wearer's skin when the disposable diaper is worn, and the term "surface "non-skin-facing" refers to a surface that is intended to face a side other than the wearer's skin side when wearing a disposable diaper. In other words, the skin-facing surface is the surface that is provided on the side relatively close to the wearer's skin, and the non-skin-facing surface is the surface that is provided on the side relatively distant from the wearer's skin. The expression "when wearing a disposable diaper" refers to a state in which the proper position of the disposable diaper is maintained when worn.

[0015]

As shown in FIG. 2, the diaper 1 has between the waist opening WH and the leg openings LH a lower waist portion W, which is provided below the wearer's waist when the diaper 1 is worn. in the same position in the longitudinal direction X as the side seams S of the diaper 1. In this embodiment, the part W below the waistband on the front side forms the front area F, and the part W located below the waistband on the back side forms the back area R .

[0016]

As shown in FIG. 2, the absorbent assembly 2 has a substantially rectangular shape when the diaper 1 is in its flat-folded, uncontracted state and is located in the area extending from the front area F to the back area R. The absorbent assembly 2 is located on a portion of the outer of the cover 3 centered in the lateral direction Y, the longitudinal direction of the absorbent assembly 2 corresponding to the longitudinal direction X of the diaper 1. The longitudinally end portions of the absorbent assembly 2 are respectively the front end portion 2F, which is located in the front region F of the diaper 1 , and a rear end portion 2R which is located in the rear region R of the diaper 1. The absorbent assembly 2 is attached to the outer cover 3 by a connecting means such as an adhesive.

[0017]

As shown in Figures 2 and 3, the absorbent assembly 2 includes a liquid-pervious topsheet 21 that forms a skin-facing surface, a a non-skin-facing surface and a liquid-retaining absorbent member 23 that is provided between the sheets 21 and 22. The absorbent member 23 is formed by covering the absorbent core 231 having absorbency with the liquid-permeable core wrap sheet 232.

[0018]

Two anti-leak cuffs 24 formed from liquid-resistant or water-repellent and breathable sheets are provided on both sides of the skin-facing surface of the absorbent assembly 2 extending along the longitudinal direction X. At least one thread-like elastic member 25 for forming a leakproof cuff is placed near the free end of each leakproof cuff 24 in a state in which it is stretched in the longitudinal direction X. When the diaper 1 is worn, the cuff 24, The leak-proof ones rise upward at least in the crotch area M due to the contraction of the elastic members 25, which are placed in a stretched state, whereby secretions such as urine are prevented from flowing outward in the lateral direction Y.

[0019]

Materials commonly used for disposable diapers can be used as the topsheet 21, backsheet 22 and absorbent member 23 without any particular limitation. For example, various types of nonwoven fabric sheets and apertured film can be used as the topsheet 21. As the back sheet 22, a resin film and a laminate of a resin film and a nonwoven material sheet or the like can be used. With regard to the absorbent member 23, the absorbent core 231 can be a collection of hydrophilic fibers such as wood pulp fibers or synthetic fibers rendered hydrophilic, the collection providing support for the absorbent polymer if necessary, and as a sheet. 232, materials similar to those described for the top sheet 21 can be used to wrap the core. Materials similar to those described for the back sheet 22 can be used as the sheets forming the leakproof cuffs.

[0020]

The outer cover 3 is located on the non-skin surface side of the absorbent assembly 2 and forms the outer shape of the diaper 1. As shown in FIG. R of the diaper 1. The parts of the outer cover located respectively in the front region F and the rear region R are rectangular in shape with a longer length in the lateral direction Y than in the longitudinal direction X. In the outer cover 3 in the crotch region M, each of the two edge of the leg portions LS, which form the side edges of the outer cover 3 defined in the lateral Y direction, is curved in an arcuate shape with an inward curvature towards the middle in the lateral Y direction.

[0021]

As shown in FIG. 3, the outer cover 3 includes a stack formed by an outer nonwoven sheet 31 forming a non-skin surface of the diaper 1 when worn, and an inner nonwoven sheet 32 disposed on the surface of the outer nonwoven sheet 31 facing the skin. In the state of wearing the diaper 1, the outer non-woven fabric sheet 31 forms a non-skin-facing surface of the diaper 1, and also forms the outer surface of the diaper 1. On the other hand, the inner non-woven fabric sheet 32 forms a skin-facing surface of the diaper 1. The outer sheet 31 of the nonwoven material and the inner sheet 32 of the nonwoven material 32 are bonded to each other at predetermined portions by a bonding means such as an adhesive.

[0022]

As shown in FIG. 3, the outer cover member 3 in the bellows portion W includes, between the outer nonwoven fabric sheet 31 and the inner nonwoven fabric sheet 32, a plurality of thread-like or flat band-like elastic members 33 of the bellows part, which are placed spaced in the longitudinal direction X while being stretched in the lateral direction Y. The elastic members 33 are provided in the peripheral portion forming the edge of the waist opening WH and may have elasticity in the lateral Y direction. legs are placed (not shown) in an extended state in the edge portions of the legs LS around the two leg holes LH. Thus, at the open edge of each of the two leg openings LH, annular leg assemblies are formed that are substantially continuous over their entire circumference. All of these elastic members are placed and secured between the outer nonwoven sheet 31 and the inner nonwoven sheet 32 by means of a bonding agent such as an adhesive. In this embodiment, the sheet which is located on the non-skin surface side of these elastic members is defined as the outer nonwoven sheet 31, and the sheet which is located on the skin side of the elastic members is defined as the inner nonwoven sheet 32. material.

[0023]

As shown in FIG. 2, the outer cover 3 has, in each of the front region F and the rear region R, a projecting portion in which at least one of the outer nonwoven fabric sheet 31 and the inner nonwoven fabric sheet 32, which form the outer cover 3 , protrudes outward from the end in the longitudinal direction X. Each projecting portion serves as a folded portion 35 that is folded onto the skin-facing surface of the inner nonwoven sheet 32 . The folded portions 35 cover both end portions, i.e., respectively, the front portion 2F and the rear portion 2R of the absorbent assembly 2, end in the longitudinal direction X. That is, as shown in FIG. at least one of the outer nonwoven sheet 31 and the inner nonwoven sheet 32 protrudes outward from the edge of the waist opening WH in the front region F and the rear region R, respectively, and these projections serve as the folded portions 35 and cover the front end portion 2F, respectively, and rear end portion 2R of the absorbent assembly 2.

[0024]

As described above, each of the folded portions 35 is formed by folding at least one of the outer nonwoven sheet 31 and the inner nonwoven sheet 32. Accordingly, the folded portions 35 may be formed by allowing only one of the outer nonwoven sheet 31 and the inner nonwoven sheet 32 to protrude outward from the edge of the waist hole WH to form the protrusion and fold the protrusion, or by allowing the protrusion as the outer sheet 31 of the nonwoven fabric and the inner sheet 32 of the nonwoven fabric outward from the edge of the waist hole WH to form the projection and fold the projection.

[0025]

The folded portions 35 located in the front region F and the rear region R, respectively, may have different nonwoven sheet configurations. More specifically, one of the folded portions 35 located in the front region F and the rear region R may be formed by folding a projecting portion composed of one of the outer nonwoven sheet 31 and the inner nonwoven sheet 32, and the other folded portion 35 may be formed by folding a protruding portion composed of the other of the outer nonwoven sheet 31 and the inner nonwoven sheet 32 or both of the nonwoven sheets. Both folded portions 35 can be formed by folding a protruding portion formed by both the outer nonwoven sheet 31 and the inner nonwoven sheet 32 .

[0026]

For reasons related to the different functions of the skin-facing surface in the anterior region and the posterior region, it is preferable that even when the folded portions 35 are formed by folding only one or both of the nonwoven fabric sheets forming the outer cover 3 , parts of the respective folded portions 35 covering the absorbent assembly 2 in these different areas had different configurations. In particular, it is preferable that, in the folded portions 35, a sheet of nonwoven material forming a surface that is proximal to the skin and is the surface of the portion 3F covering the front end portion 2F of the absorbent assembly 2 (hereinafter, the portion 3F is also referred to as "the front covering portion 3F "") was different from the nonwoven sheet forming a surface that is proximal to the skin and is the surface of the portion 3R covering the rear end portion 2R of the absorbent assembly 2 (hereinafter, the portion 3R is also referred to as "rear cover portion 3R"). More specifically, (i) it is preferable that the front cover portion 3F is formed such that the outer nonwoven sheet 31 is disposed on the skin side, and the back cover portion 3R is composed of the inner nonwoven sheet 32. In alternative (ii), it is preferable that the front cover portion 3F is composed of an inner nonwoven sheet 32, and the back cover portion 3R is formed such that the outer nonwoven sheet 31 is located on the skin side.

[0027]

In the above-described case (i), the front cover portion 3F is composed of the outer nonwoven sheet 31, or the front cover portion 3F is formed by both the outer nonwoven sheet 31 and the inner nonwoven sheet 32, with the outer nonwoven sheet 31 located closer to the side. surface facing the skin than the inner sheet 32 of the nonwoven fabric. In the above-described case (ii), the back cover portion 3R is composed of the outer nonwoven sheet 31, or the back cover portion 3R is formed by both the outer nonwoven sheet 31 and the inner nonwoven sheet 32, with the outer nonwoven sheet 31 located closer to the side. surface facing the skin than the inner sheet 32 of the nonwoven fabric. Thus, in this embodiment, the nonwoven sheet forming the skin-facing surface of the front cover portion 3F and the non-woven sheet forming the skin-facing surface of the back cover portion 3R are different from each other. More specifically, the outer nonwoven sheet 31 and the inner nonwoven sheet 32 have different properties.

[0028]

With respect to the outer nonwoven sheet 31 and the inner nonwoven sheet 32 which form the outer cover 3, "different from each other" means that the nonwoven sheets have different properties. Examples of nonwoven fabric sheets having different properties include: a combination of nonwoven fabric sheets that are made by the same manufacturing method but use different starting materials or materials obtained under different fiber spinning conditions; a combination of nonwoven fabric sheets that are made by different manufacturing methods; a combination of sheets of nonwoven material that differ in whether they have elasticity or not, or differ in the degree of elasticity; a combination of nonwoven sheets that differ in whether their constituent fibers have been subjected to a hydrophilic treatment or a hydrophobic treatment or not, or differ in the degree of treatment or the type of treatment agent used; a combination of sheets of nonwoven material that differ in the number of fibrous sheets forming each sheet of nonwoven material; a combination of nonwoven fabric sheets that differ in whether they have holes or not, or differ in the size/proportion of holes, and a combination of nonwoven fabric sheets which differ in whether non-fusion-bonded hydrophilic fibers are mixed in , or not, or differ in the relative amount of intervening fibers.

[0029]

In the embodiment shown in FIGS. 1-3, the outer nonwoven sheet 31 and the inner nonwoven sheet 32 are substantially inelastic nonwoven sheets and do not have apertures. In addition, the front cover portion 3F is formed by only the inner nonwoven sheet 32, and the back cover portion 3R is formed by only the outer nonwoven sheet 31. The cover portions in the present invention are portions formed by the bent portions 35 as described above. Accordingly, the folded portions 35 in the present invention are integrally formed by the outer cover member 3, and hence a portion such as a sheet-like member, such as another sheet of nonwoven fabric, attached or attached in addition to or instead of the nonwoven fabric sheets forming the folded portions, for arranging this sheet-like member so as to cover the front end portion 2F and the rear end portion 2R of the absorbent assembly 2 does not correspond to the cover portion in the present invention. The manufacturing efficiency of the disposable diaper as well as the breathability of the disposable diaper can be improved by forming the folded portions 35 as one unit by using the outer cover 3 without accommodating separate sheet-like members.

[0030]

To improve wearing comfort, it is even more preferred that the parts of the pull-on disposable diaper that come into contact with the ventral side and the dorsal side of the wearer, respectively, perform different functions. More specifically, since the location of the excretory part, the movement caused by, for example, breathing, and, for example, the sweating state on the ventral side are different from the location of the excretory part, the movement caused by breathing, and the sweating state on the dorsal side, it is preferable to change the configurations according to with these conditions. "Miscellaneous functions" provided by the present invention refer to various functional characteristics associated with improved wearing comfort, such as flexibility, elasticity, ability to follow the movement of the wearer, water resistance to aqueous excretions such as urine and feces, affinity for sweat (sweat-absorbing capacity) and breathability, and the cover portions may perform the same type of function to a different degree, or may perform a different type of function. These functions can be performed individually or in combination. The above-described various functions can be effectively performed by selecting a configuration in which the front cover 3F and the back cover 3R have different properties.

[0031]

As an example of a configuration in which the cover portions have different properties, it is preferable that the front cover portion 3F has a lower rigidity than the rear cover portion 3R. This configuration makes the front cover 3F highly flexible, so that the front cover 3F will easily follow the movement of the abdomen caused by breathing, and also this configuration makes the back cover 3R low flexibility, and therefore prevents the edge constituent members from bending or curling. holes for the waist and the like in the back. Therefore, wearing comfort can be improved.

[0032]

Stiffness can be controlled by, for example, forming the outer nonwoven sheet and the inner nonwoven sheet with different warp weights, using fibers with different fiber diameters for the respective nonwoven sheets, or forming the nonwoven sheets in different manufacturing methods. Generally, lower warp weight and smaller fiber diameters result in lower stiffness. With regard to the manufacturing methods of the nonwoven sheet, the stiffness decreases in the following order: SMS structure nonwoven sheet (spunbonded layer - melt blown layer - spunbonded layer), spunbond nonwoven sheet and a sheet of nonwoven fabric bonded by passing air through. Rigidity can also be increased by performing hot roll processing. As raw materials used in methods for producing a nonwoven fabric sheet, thermoplastic resins such as polyethylene (PE), polypropylene (PE), polyesters (polyethylene terephthalate (PET) and polybutylene terephthalate (PBT)) and polyamide can be used.

[0033]

The ratio F1/R1 of the stiffness (F1) of the front cover portion 3F to the stiffness (R1) of the rear cover portion 3R is preferably 0.3 or more, and more preferably 0.4 or more, and preferably 0.8 or less, and more preferably 0.75 or less. The stiffness (F1) of the front cover portion 3F is preferably 2 cN or more, and more preferably 3 cN or more, and preferably 6 cN or less, and more preferably 5 cN or less. The rigidity (R1) of the back cover portion 3R is preferably 4 cN or more, and more preferably 5 cN or more, and preferably 15 cN or less, and more preferably 13 cN or less.

[0034]

The rigidity of the covering parts can be determined by using, for example, the method below. Specifically, in an environment with a temperature of 22°C and a relative humidity of 65%, a MD ( machine direction ) stiffness sample and a CD ( cross-machine direction ) hardness sample are cut from each of the nonwoven fabric sheets, forming the covering parts 3F and 3R. The MD-direction stiffness test specimen is cut so that the length in the MD-direction is 150 mm, which direction corresponds to the orientation direction of the constituent fibers of the nonwoven sheet included in the cover portion 3F or 3R, and the length in the CD-direction perpendicular to to the MD direction was 30 mm. Thereafter, the end portions of the sample are attached to each other at two places, namely, the top and bottom, using a stapler to form an annular shape with a diameter of 45 mm, whereby an annular sample is obtained. In this case, the staples are oriented so that they have a longer length in the MD direction. Similarly, the sample for determining the stiffness in the CD direction is cut with a length of 150 mm in the CD direction, which is perpendicular to the orientation direction of the constituent fibers of the nonwoven sheet included in the 3F or 3R cover portion, and a length of 30 mm in the MD direction, which corresponds to the orientation direction of the constituents. fibers. Thereafter, the end portions of the sample are attached to each other at two places, namely, the top and bottom, using a stapler to form an annular shape with a diameter of 45 mm, whereby an annular sample is obtained. The staples are oriented so that they are longer in the CD direction. Allow each of the obtained annular samples to stand like a cylinder on the sample table, and using a tensile tester (for example, a TENSILON “RTA-100” tensile tester manufactured by ORIENTEC CORPORATION), the annular sample is compressed from above, with a flat plate substantially parallel to the table surface, at a compression speed of 10 mm/min and during the compression period, the maximum load (N) is measured. The arithmetic mean of the obtained values for the MD direction and the obtained values for the CD direction is used as the stiffness (H). The greater the maximum load, the higher the rigidity.

[0035]

As another example of a configuration in which the cover portions have different properties, it is preferable that the front cover portion 3F has a higher water resistance than the rear cover portion 3R. This configuration makes the front cover portion 3F highly water-resistant to suppress the leakage of water-containing exudates such as urine and feces from the disposable diaper thereby, and also this configuration makes the back cover portion 3R highly hydrophilic to exhibit sweat absorption capacity thereby, so that when in use, the wearer may experience an improved feel. The water resistance can be controlled, for example, by forming an outer nonwoven sheet and an inner nonwoven sheet with different warp weights, using fibers with different fiber diameters for the respective nonwoven sheets, making the nonwoven sheets in different manufacturing methods, or using nonwoven sheets that differ in whether they have been subjected to a hydrophilic treatment or a hydrophilic treatment or not, or differ in the degree of treatment or the type of hydrophilic agent or hydrophobic agent used.

[0036]

For reasons related to providing even more prominent advantages described above, it is preferable that the difference F2 - R2 of the water pressure resistance (F2) provided by the front cover part 3F and the water pressure resistance (R2) provided by the back cover part 3R is preferably 10 mm or more and more preferably 15 mm or more and preferably 500 mm or less and more preferably 400 mm or less, provided that F2 > R2. For the same reason, the water pressure resistance (F2) provided by the front cover portion 3F is preferably 10 mm or more, and more preferably 15 mm or more, and preferably 500 mm or less, and more preferably 400 mm or less. For the same reason, the water pressure resistance (R2) provided by the back cover portion 3R is preferably 0 mm or more, and preferably 50 mm or less, and more preferably 40 mm or less.

[0037]

The degree of water resistance of the covering parts can be expressed by the water level (mm) as the water pressure resistance in the water resistance test. The water resistance is determined in accordance with the water penetration test prescribed in JIS L1092 ( JIS - Japanese Industrial Standard ) (Hydrostatic head determination method: Method B). A higher level (mm) of water in the water resistance test means higher water resistance.

[0038]

For the same reason, it is also preferred that the front cover 3F has a lower hydrophilicity than the back cover 3R. This configuration provides a low hydrophilicity of the front cover portion 3F to suppress the leakage of water-containing exudates such as urine and feces from the disposable diaper thereby, and also this configuration provides an increased affinity of the back cover portion 3R for sweat to exhibit sweat absorption capacity thereby, so that when used, the wearer can create an improved feeling. The hydrophilicity can be controlled, for example, by using nonwoven sheets that differ in whether the nonwoven sheets have been subjected to a hydrophilic treatment or a hydrophilic treatment or not, or by adjusting the degree of treatment, or by using different types of hydrophilicity agents or means for imparting hydrophobicity to the sheets of nonwoven material, or interfering with hydrophilic fibers in one of the sheets of nonwoven material.

[0039]

The hydrophilicity of the side of the surface of the covering parts facing the skin is evaluated using a two-point scale.

First, whether the nonwoven fabric sheets have water absorbency is determined according to “JIS L 1907: Testing methods for water absorbency of textiles” (Test methods for determining the water absorbency of textiles). Specifically, the nonwoven fabric sheets included in the cover portions are cut into pieces with dimensions of 100 mm in the MD direction × 100 mm in the CD direction, and the cut pieces are used as measurement samples. The measurement sample is attached to the holding frame with the skin-facing surface of the measurement sample facing upwards, and one drop of water (approximately 0.04 ml) is dropped from a height of 10 mm above the test sample. The time interval from the moment when the drop of water has reached the sample to be measured, until the moment when the specular reflection ("brilliant" reflection of light) on the water completely disappears, is measured by means of a stopwatch. If the measurement sample is small, the evaluation is performed using a measurement sample having a size that can be considered appropriate. Meanwhile, a hand-made wooden frame or the like suitable for a given measurement sample size is used as a holding frame. Evaluate three samples for measurement, and calculate the average value of the time until the disappearance of the water drop. A nonwoven fabric sheet for which the average time to disappear water drop is 10 seconds or more is defined as a hydrophobic nonwoven fabric sheet, and a nonwoven fabric sheet for which the average value is less than 10 seconds is defined as a hydrophilic nonwoven fabric sheet. If one and the other of the front cover portion 3F and the back cover portion 3R are respectively a hydrophobic nonwoven sheet and a hydrophilic nonwoven sheet, it is determined that the nonwoven sheet, which is the hydrophobic nonwoven sheet, has a lower hydrophilicity than the hydrophilic sheet. nonwoven fabric. If both the front cover 3F and the back cover 3R are sheets of hydrophobic nonwoven fabric, hydrophilicity is evaluated using a nonwoven sheet contact angle measurement method to be described later. If both the front cover 3F and the back cover 3R are hydrophilic nonwoven sheets, hydrophilicity is evaluated using the Klemm method for determining water absorption capacity by lift height, which will be described later.

[0040]

If both the front cover portion 3F and the back cover portion 3R are hydrophobic nonwoven sheets, the degree of hydrophilicity of the cover portions can be expressed by the water contact angle (°). The contact angle can be determined by using, for example, the method below.

Nonwoven Sheet Contact Angle Measurement Method

The measurement is performed using a microscope (VHX-1000 manufactured by KEYENCE CORPORATION) with a medium magnification zoom lens that is tilted at an angle of 90°. The nonwoven fabric sheets included in the cover portions are cut into pieces with dimensions of 150 mm in the MD direction × 70 mm in the CD direction, and the cut pieces are used as measurement samples. The measurement is performed in an environment with a temperature of 20°C and a relative humidity of 50%, and the measurement sample is placed on the measurement stage so that the skin-facing surface of the cover portion faces upward and so that the measurement sample can be viewed in the CD direction of the nonwoven fabric sheet. Then, 3 μl of ion-exchange water is deposited on the measurement sample placed on the measurement stage, and images of this condition are allowed to be captured. Inspection images are selected in which either one or both of the ends of the water drop on the nonwoven sheet are clearly visible, and the contact angle is measured at 10 ends in the selected inspection images. The arithmetic mean of the obtained values is used as the contact angle (°). Smaller contact angle means higher hydrophilicity. If the folded portions are too small to take a given size sample from them, the absorbent assembly is separated from the outer cover and the outer cover is separated into an outer nonwoven sheet and an inner nonwoven sheet. If the nonwoven sheets are bonded by fusion bonding or by an adhesive, the bonded portions are melted by applying a solvent or supplying hot air from a dryer or the like and discarded, and the nonwoven sheets are then separated and used as measurement samples.

[0041]

If both the back cover part 3R and the front cover part 3F are hydrophobic, the difference F3 − R3 of the hydrophilicity (F3) of the front cover part 3F and the hydrophilicity (R3) of the back cover part 3R is preferably 15° or more, and more preferably 20° or more and is preferably 90° or less, and more preferably 80° or less, provided that F3 > R3. The hydrophilicity (F3) of the front cover portion 3F is preferably 105° or more, and more preferably 110° or more, and preferably 180° or less, and more preferably 170° or less. The hydrophilicity (R3) of the back cover portion 3R is preferably 90° or more, and more preferably 95° or more, and preferably 150° or less, and more preferably 145° or less.

[0042]

If both the front cover 3F and the back cover 3R are sheets of hydrophilic nonwoven material, the degree of hydrophilicity of the cover parts can be expressed by water absorption capacity, which is determined by the lift height in the Klemm method. This water absorption capacity can be determined by using the following method in accordance with JIS P 8141.

Method for determining the water absorption capacity expressed by the height of the rise in the Klemm method

From the nonwoven fabric sheets included in the cover portions, (1) a piece with a width (length in the longitudinal direction (X direction) of the diaper 1) of 30 mm and a length (length in the lateral direction (Y direction) of the diaper 1) is cut separately, 150 mm, and (2) a piece with a width (length in the longitudinal direction (X direction) of the diaper 1) of 150 mm and a length (length in the lateral direction (Y direction) of the diaper 1) of 30 mm, and cut pieces used as samples for measurements. Next, each of the cut samples is attached to a fixture specified in JIS P 8141 so that the longitudinal direction of the sample matches the vertical direction. Water is used as the test liquid, and the water absorption capacity is determined by the lift height after 60 seconds have elapsed. To facilitate reading of the soak height, the test fluid may be appropriately colored with a dye such as No. 1 blue or methylene blue. The sample from the sample (1) and the sample (2) which has the greater water absorption capacity expressed as the lift height is determined, and the measurement for this particular sample is performed five times. The arithmetic average of the obtained values is used as the ability of the front cover 3F or the back cover 3R to absorb water, and this ability is expressed as a height (mm) in the Klemm method. A higher water absorption value, expressed in terms of height in the Klemm method, means higher hydrophilicity. The temperature of the environment in which measurements are performed is set to 22°C. If the folded portions are too small to take sized samples from them, the absorbent assembly is separated from the outer cover and the outer cover is separated into an outer nonwoven sheet and an inner nonwoven sheet. If the nonwoven sheets are bonded by fusion bonding or by adhesive, the measurement is performed on the parts that are not bonded, or alternatively, the bonded parts are removed and samples are taken for measurement. In this case, in order to minimize the impact on the hydrophilic agent applied to the constituent elements, it is preferable to avoid using a method of removing the bonded parts, which can cause destruction or loss of this agent, that is, such a method as applying a solvent or blowing hot air from a dryer.

[0043]

If both the back cover part 3R and the front cover part 3F are hydrophilic, the difference R3 to F3 of the hydrophilicity (R3) of the back cover part 3R and the hydrophilicity (F3) of the front cover part 3F is preferably 3 mm or more, and more preferably 5 mm or more and is preferably 100 mm or less, and more preferably 90 mm or less. The hydrophilicity (F3) of the front cover portion 3F is preferably 0 mm or more, and preferably 20 mm or less, and more preferably 10 mm or less. The hydrophilicity (R3) of the back cover portion 3R is preferably 3 mm or more, and more preferably 5 mm or more, and preferably 100 mm or less, and more preferably 90 mm or less.

[0044]

The sheet of hydrophilic nonwoven material is mainly composed of hydrophilic fibers that can be bonded by fusion. Fusion bondable hydrophilic fibers include fibers that have been treated to be hydrophilic and therefore have a contact angle of less than 90°. Examples of such fibers include fibers with hydrophilicity impregnated therein, fibers with hydrophilicity attached to their surface, and fibers subjected to plasma treatment. There is no particular restriction on the hydrophilic agent, and conventional hydrophilic agents which are used for hygiene products can be used. The hydrophilic nonwoven sheet may also include non-fusion bondable hydrophilic fibers such as natural fibers, regenerated cellulose fibers, or semi-synthetic fibers. Examples of natural fibers include cotton fibers, silk fibers and cellulose fibers, as well as refined cellulose fibers such as lyocell fibers. Examples of regenerated cellulose fibers include regenerated fibers such as rayon fibers and ammonia copper fibers, and examples of semi-synthetic fibers include acetate fibers.

[0045]

The hydrophobic nonwoven web is composed of hydrophobic fusion bondable fibers and includes fibers that have been treated to be hydrophobic and therefore have a contact angle of 90° or more. Examples of such fibers include fibers with a hydrophobic agent incorporated therein, fibers with a hydrophobic agent attached to their surface, and fibers subjected to plasma treatment. There is no particular restriction on the hydrophobic agent, and conventional hydrophobic agents which are used for hygiene products can be used.

[0046]

As a specific example of a configuration in which the cover portions have different properties, it is preferable that the front cover portion 3F has a lower warp weight than the rear cover portion 3R. This configuration makes the front cover part 3F highly flexible so that the front cover part 3F easily follows the movement of the abdomen caused by breathing, and also this configuration makes the back cover part 3R low flexibility, and therefore prevents the constituent members of the edge of the waist hole and the like in the back. In addition, this configuration also makes the back cover portion 3R highly hydrophilic to exhibit sweat absorption capacity thereby. Therefore, even more improvement in the feel of the wearer can be achieved in use.

[0047]

The ratio F4/R4 of the weight of the base (F4) of the front cover portion 3F to the weight of the base (R4) of the back cover portion 3R is preferably 0.65 or more, and more preferably 0.75 or more, and preferably 0.90 or less, and more preferably 0. .85 or less. The basis weight (F4) of the front cover portion 3F is preferably 11 g/m ² or more, and more preferably 15 g/m ² or more, and preferably 25 g/m ² or less, and more preferably 20 g/m ² or less. The base weight (R4) of the back cover portion 3R is preferably 14 g/m ² or more, and more preferably 16 g/m ² or more, and preferably 35 g/m ² or less, and more preferably 30 g/m ² or less. The basis weight (g/m ² ) can be determined by cutting a piece of predetermined dimensions from the sheet of nonwoven material to be measured, which is then used as a sample, and dividing the mass (g) of the sample by the area (m ² ) of the sample in view in plan.

[0048]

For the same reasons, the diameter of the fibers constituting the fibers of the front cover portion 3F is preferably equal to or less than, more preferably less than the diameter of the fibers constituting the fibers of the back cover portion 3R. This configuration provides improved flexibility, motion/shape repeatability, and water resistance of the front cover 3F, and the high water resistance of the front cover 3F can suppress leakage of water-containing exudates such as urine and feces from the disposable diaper. In addition, this configuration provides increased rigidity of the rear cover portion 3R. To determine the diameter (µm) of the fibers, the cross sections of the ten fibers extracted from the nonwoven sheet of interest are measured using, for example, a scanning electron microscope (Model S-4000 manufactured by Hitachi, Ltd.) and the arithmetic mean of the obtained values are used as the diameter of the fibers. If the nonwoven sheet of interest is a sheet of material in which a plurality of fibrous layers with different fiber diameters are stacked on top of each other, such as a sheet with an SMS structure, the diameter of each of the different constituent fibers is measured, and the average is calculated taking into account proportion of respective fibers (mass ratio) in the nonwoven sheet is used as the average fiber diameter of the nonwoven sheet.

[0049]

The ratio F5/R5 of the diameter (F5) of the fibers constituting the fibers of the front cover portion 3F to the diameter (R5) of the fibers constituting the fibers of the rear cover portion R3 is preferably 0.4 or more, and more preferably 0.5 or more and is preferably 1.0 or less, and more preferably 0.9 or less. The diameter (F5) of the fibers constituting the fibers of the front cover portion 3F is preferably 9 µm or more, and more preferably 10 µm or more, and preferably 20 µm or less, and more preferably 15 µm or less. The diameter (R5) of the fibers constituting the fibers of the R3 back cover portion is preferably 11 µm or more, and more preferably 13 µm or more, and preferably 22 µm or less, and more preferably 20 µm or less.

[0050]

As another example of a configuration in which the cover portions have different properties, it is preferable that the nonwoven sheet included in the back cover portion 3R has a plurality of holes, and it is also preferable that the nonwoven sheet included in the front cover portion 3F does not had holes to suppress the leakage of secretions. With this configuration, the front cover portion 3F can suppress leakage of water-containing exudates such as urine and feces from the disposable diaper. In addition, this configuration provides high breathability of the back cover portion 3R to prevent moisture when wearing the disposable diaper. Therefore, the wearer can feel better when used. Preferably, the openings are waterproof and breathable.

[0051]

In order to effectively perform the above-described various functions on the front side and the back side, and to improve the manufacturing efficiency of the disposable diaper, it is more preferable that the front cover portion 3F is composed of an inner nonwoven sheet 32, and that the outer nonwoven sheet 31 forms the surface of the back cover portion 3R, facing the skin. A disposable diaper having a configuration can be successfully manufactured by using a manufacturing method to be described later. In particular, it is even more preferable that in the back cover portion 3R, only the outer sheet 31 of the nonwoven material covers the rear end portion 2R of the absorbent assembly 2. The diaper 1 configured can perform many different functions from the front side and the back side even more effectively.

[0052]

As shown in FIG. 1, in the diaper 1, the outer cover 3 in the bellows portion W includes, between the outer nonwoven fabric sheet 31 and the inner nonwoven fabric sheet 32, a plurality of thread-like or flat band-like elastic members 33 of the bellows portion. which are spaced in the longitudinal X direction while being stretched in the lateral Y direction. band-like leg elastics (not shown) are placed in an extended state in the leg end portions LS around the two leg openings LH. Thus, at the open edge of each of the two leg openings LH, annular leg assemblies are formed that are substantially continuous over their entire circumference. All of these elastic members are placed and secured between the outer nonwoven sheet 31 and the inner nonwoven sheet 32 by means of a bonding agent such as an adhesive.

[0053]

An embodiment of the disposable diaper of the present invention has been described above, in which elastic members are placed between an outer nonwoven fabric sheet and an inner nonwoven fabric sheet, which form an outer cover member. Hereinafter, another embodiment of the disposable diaper of the present invention will be described. In the following description, only the differences from the above embodiment are described, and the above description is appropriately valid for the rest. Elements that are the same as those of the above embodiment are designated by the same reference numerals.

[0054]

As shown in Fig. 4, the disposable diaper of this embodiment has no elastic members between the outer nonwoven sheet 31 and the inner nonwoven sheet 32 provided in the outer cover 3. In the disposable diaper shown in Fig. 4, it is preferable that instead of using elastic members, one of the outer nonwoven sheet 31 and the inner nonwoven sheet 32 is an elastic nonwoven and the other of them is an inelastic nonwoven. In addition, it is also preferable that the nonwoven fabric sheet forming the surface that is closest to the skin and is the surface of the front cover portion 3F is an elastic nonwoven fabric, and that the nonwoven fabric sheet that forms the surface that is closest to the skin and is the surface of the back cover portion 3R was an inelastic non-woven fabric. This configuration provides high elasticity of the front cover 3F so that the front cover 3F easily follows the movement of the abdomen caused by breathing, and also this configuration provides low elasticity of the back cover 3R and therefore prevents, for example, bending, twisting or shifting of the constituent members. the edges of the opening for the waist and the like in the back. Therefore, a better feeling can be provided to the wearer in use. The positions of the outer nonwoven sheet 31 and the inner nonwoven sheet 32 in this embodiment can be determined based on whether the nonwoven sheets have elasticity or not.

[0055]

In addition, in order to improve manufacturing efficiency of the disposable diaper, it is more preferable that the front cover portion 3F is formed from the inner nonwoven sheet 32 and that the back cover portion 3R is formed from the outer nonwoven sheet 31. In other words, it is more preferable that the inner nonwoven fabric sheet 32 is an elastic nonwoven fabric and forms the front cover part 3F, and the outer nonwoven fabric sheet 31 is an inelastic nonwoven fabric and forms the back cover part 3R.

[0056]

Examples of the elastic nonwoven fabric used in the present invention include a multilayer nonwoven fabric having a layer of elastic fibers formed from an elastic resin, and a layer of substantially inelastic fibers located on at least one surface of the elastic fiber layer, which layers bonded together by fusion bonding while still maintaining their fiber shapes, and the stretch sheets disclosed in JP 2008-179128A and JP 2007-22066A. Examples of elastic fibers include fibers formed from an elastic resin such as a thermoplastic elastomer such as a styrene-based elastomer, a polyolefin-based elastomer, a polyester-based elastomer or a polyurethane-based elastomer, or rubber. Examples of inelastic fibers include fibers formed from a thermoplastic resin such as those described above.

[0057]

Another embodiment of the disposable diaper of the present invention will be described with reference to FIG. In the following description, only the differences from the above embodiments are described, and the above description is appropriately valid for the rest. Elements that are the same as those of the above embodiments are designated by the same reference numerals.

[0058]

The diaper 1 shown in FIG. 5 includes an outer cover 3 which is divided into a front outer cover 3A which is provided on the ventral side of the wearer, and a rear outer cover 3B which is provided on the dorsal side of the wearer, and an absorbent assembly 2, which connects and is attached to the front outer cover 3A and the rear outer cover 3B. The longitudinally end portions of the absorbent assembly 2 overlap and are attached to the front outer cover 3A and the rear outer cover 3B, respectively, and these end portions correspond to the front end portion 2F and the rear end portion 2R. Both end portions of the front outer cover 3A and both end portions of the rear outer cover 3B are attached to each other to form two side seams S, and therefore, these two outer cover members are connected to each other to form an annular shape.

[0059]

The disposable diaper of the present invention has been described above. Hereinafter, an embodiment (first embodiment) of a method for manufacturing a disposable diaper of the present invention will be described. In this embodiment, by using the manufacturing equipment 100 shown in FIG. 6, the following steps are performed: the continuous outer nonwoven sheet 31S and the continuous inner nonwoven sheet 32S are stacked one on top of the other so that the side edge of one sheet, defined in the width direction, projected outward from the other sheet, to form a continuous outer cover member 3S thereby; the absorbent units 2 are placed on the side of the continuous outer cover 3S that is the side of the continuous inner nonwoven sheet 32S at intervals in the moving direction MD; then, both side areas of the continuous outer cover 3S, defined in the width direction CD, are folded into the absorbent units 2; the continuous outer cover with the absorbent nodes is folded in half in the part central in the width direction; thereafter, the portions of the continuous outer cover 3S, which become opposed to each other as a result of being folded in half, are connected to each other at the positions between the absorbent nodes 2 adjacent to each other in the direction of movement MD, to form the connected zones 37 thereby, and therefore, forming the continuous diaper 1A, and the continuous diaper 1A is cut at the connected areas 37 along the width direction of the continuous diaper 1A. In the following description, the direction that is perpendicular to the moving direction MD is referred to as the width direction CD.

[0060]

First, the continuous outer nonwoven sheet 31S and the continuous inner nonwoven sheet 32S are stacked on top of each other to form the continuous outer cover 3S. Two continuous nonwoven sheets 31S and 32S are stacked one on top of the other so that an overlapping portion 3M is formed in which the continuous nonwoven sheets 31S and 32S overlap each other in the width direction CD. In other words, the continuous nonwoven fabric sheets 31S and 32S are stacked one on top of the other so that their side edges do not match on at least one side defined in the width direction CD. Specifically, the continuous inner nonwoven sheet 32S protrudes outward in the width direction from one side edge of the overlap portion 3M defined in the width direction CD. The continuous nonwoven sheets 31S and 32S are preferably stacked one on top of the other so that both side edges of the sheets, defined in the width direction CD, do not coincide with each other. Continuous sheets 31S and 32S of nonwoven material in this state are introduced into the area between the two pressure rollers 61 and squeezed between them to be bonded together thereby. Thus, a continuous outer cover 3S is formed. In the continuous outer cover 3S, one of the two continuous sheets of nonwoven fabric projects outward in the width direction CD from one of the side edges of the overlap portion 3M defined in the width direction, and the other of the two continuous sheets of nonwoven fabric projects outward in the width direction CD from the other. side edge of the 3M part with overlap. Alternatively, in the continuous outer cover 3S, one of the two continuous nonwoven sheets extends outward in the width direction CD from one of the side edges of the overlapping portion 3M defined in the width direction, but on the other side edge of the overlapping portion 3M, with the position of the side edges overlapping of the two continuous sheets of nonwoven fabric are the same. In the continuous outer cover 3S, the continuous nonwoven sheets 31S and 32S are bonded to each other, for example, by adhesive in the overlap portion 3M, but the two continuous nonwoven sheets are not bonded to each other in both side regions of the continuous outer cover 3S, defined in the CD width direction.

[0061]

When forming the diaper 1 in which elastic members are provided between the outer nonwoven fabric sheet 31 and the inner nonwoven fabric sheet 32 as shown in FIG. the nonwoven fabric sheet 32S so that the continuous elastic members are placed at the positions corresponding to the overlapping part 3M of the continuous nonwoven fabric sheets 31S and 32S, and then these two continuous nonwoven fabric sheets are pressed between the pressure rolls to be bonded together thereby. Thus, a continuous outer cover 3S can be formed in which a plurality of elastic members are placed between the continuous nonwoven sheets 31S and 32S.

[0062]

In the step of forming the continuous outer cover 3S, the continuous nonwoven sheets 31S and 32S are bonded to each other at the locations between two adjacent elastic members of the bellows portion by means of connecting means such as a lug roll 12 and a corresponding anvil roll 13. If necessary, each of the continuous elastic members is then cut into a plurality of pieces by a means (not shown) for pre-cutting the elastic member at locations corresponding to the locations where the absorbent units 2 described later are to be placed, so that the elastic members are not will show a functional ability to contract. As means for pre-cutting the elastic member, for example, the elastic member separating device used in the method for manufacturing a composite stretch member disclosed in JP 2002-253605A can be used.

[0063]

Next, the absorbent nodes 2 are placed on the side of the continuous outer cover 3S that is the side of the continuous inner nonwoven sheet 32S so that the longitudinal direction of the absorbent nodes 2 corresponds to a direction perpendicular to the moving direction MD of the continuous outer cover 3S. The absorbent units 2 are placed in a state in which their longitudinal direction coincides with the width direction CD, which is a direction perpendicular to the moving direction MD of the continuous outer cover 3S.

[0064]

More specifically, the absorbent nodes 2 are made by a separate manufacturing process, and the adhesive is applied to the surface of each absorbent node 2, which should face the continuous inner sheet 32S of nonwoven material. Thereafter, the absorbent nodes 2 to which the adhesive has been applied are placed on the continuous inner nonwoven sheet 32S included in the continuous outer cover 3S at intervals in the moving direction MD, and then attached thereto. The absorbent nodes 2 are attached so that their longitudinal direction corresponds to a direction perpendicular to the moving direction MD. Thereafter, in the continuous outer cover 3S on which the absorbent nodes 2 are placed, annular cutouts are formed in the areas between adjacent absorbent nodes 2 to form leg openings LO thereby.

[0065]

Subsequently, both side regions of the continuous outer cover 3S, defined in the width direction CD, are folded onto the absorbent nodes 2. More specifically, when the continuous outer cover 3S on which the absorbent nodes 2 have been placed is moved in the moving direction MD, the first folded portion 35A, formed by folding one of the side regions of the continuous outer cover 3S covers the end regions 2A of the absorbent body 2 from the side of one end defined in the longitudinal direction. In addition, the second folded portion 35B formed by folding the other side region of the continuous outer cover 3S covers the end regions 2B of the absorbent body 2 from the other end defined in the longitudinal direction. The folded portions 35A and 35B are secured by bending and adjusting the width of the folded portions so that (1) the portion which is in the folded portion 35A of one of the side regions and covers the end regions 2A of the absorbent units 2 from the side of one end defined in the longitudinal direction, and (2) the portion that is in the folded portion 35B of the other side region and covers the end regions 2B of the absorbent units 2 from the other end defined in the longitudinal direction were formed from nonwoven fabric sheets having different properties.

[0066]

More specifically, since each of the side regions of the continuous outer cover 3S that were obtained by the above process is formed by one or the other of the continuous nonwoven fabric sheets 31S and 32S projecting outward in the width direction CD from the overlap portion 3M, each of the folded portions 35A and 35B will be formed by at least one or the other of the continuous nonwoven sheets 31S and 32S. With respect to the individual folded portions 35A and 35B having a configuration, the folded portion 35A formed by one of the side regions is fixed by bending and adjusting the width of the folded portion 35A so that its portion covering the end regions 2A of the absorbent units 2 from one end defined in the longitudinal direction, consisted of a continuous inner sheet 32S nonwoven fabric. Similarly, the folded portion 35B formed by the other side region is fixed by bending and adjusting the width of the folded portion 35B so that its portion covering the end regions 2B of the absorbent units 2 from the other end defined in the longitudinal direction is formed by two continuous sheets of nonwoven material or consisted of a continuous outer sheet 31S nonwoven fabric. By this step, the parts serving as the front cover part 3F and the back cover part 3R of the diaper 1, respectively, as shown in FIG. .

[0067]

Thereafter, the continuous outer cover 3S with the absorbent units 2, the longitudinally end zones of which are closed by the folded portions, is folded in half in its portion central in the width direction CD, and the portion of the continuous outer cover 3S, which has become opposite to each other in the result of being folded in half are connected to each other at the positions between the absorbent units 2 adjacent to each other in the moving direction MD to form the connected zones 37 therewith. Thus, a continuous diaper 1A is formed. The connected zones 37 may be formed, for example, by heat sealing or ultrasonic welding.

[0068]

Finally, the continuous diaper 1A is cut at the connected zones 37 along the width direction of the continuous diaper 1A. In this way, parts of the connected zones 37 serve as side seams S, and it is possible to successively produce pull-on disposable diapers 1 each including an outer cover 3 having two side seams S.

[0069]

The connection and cutting of the continuous outer cover 3S can be performed in one step. For example, the portions of the continuous outer cover 3S to be cut are irradiated with a laser beam, whereby the outer cover is cut while the outer cover is joined by heat fusion. In this way, it is also possible to successively manufacture the pull-on disposable diapers 1 by forming two side seams S, wherein each of the pull-on disposable diapers 1 includes an outer cover 3 having two side seams S. In each disposable diaper 1 made by using this method of manufacture, the outer cover 3 has a continuous shape and extends from the front area F to the back area R through the crotch area M.

[0070]

A method for manufacturing a diaper according to an embodiment in which the outer cover 3 has a continuous shape and extends from the front region F to the rear region R through the crotch region M has been described. invention. In this embodiment, by using the production equipment 200 shown in FIG. 7, a so-called split-type diaper is manufactured. In this type of diaper, the outer cover 3 includes a front outer cover 3A, which is provided on the ventral side of the wearer, a rear outer cover 3B, which is provided on the dorsal side of the wearer, and an absorbent assembly 2, which connects the front and rear outer covers. and attached thereto, and the front outer cover and the rear outer cover are connected to each other to form an annular shape. In the following description, the differences from the above-described manufacturing method will be described, and the description referring to the above-described manufacturing method shall accordingly apply to the rest.

[0071]

First, as in the case of the first embodiment, the continuous outer nonwoven sheet 31S and the continuous inner nonwoven sheet 32S are stacked on top of each other to form an overlap portion 3M and a continuous outer cover member 3S in which one of the two continuous nonwoven sheets protrudes. outward in the width direction from at least one side edge of the overlap portion 3M.

[0072]

Further, the continuous outer cover 3S is separated by a separating means to form two 3D outer cover parts obtained by cutting. The continuous outer cover 3S is divided in the central part of the continuous outer cover 3S, i.e., in the area in which the overlapped part 3M is located, and the two cut parts 3D of the outer cover have substantially the same width. In at least one of the cut portions 3D of the outer cover, its side edge inner in the width direction and created by separating the continuous outer cover 3S is formed by a continuous outer nonwoven sheet 31S and a continuous inner nonwoven sheet 32S, and the outer in the width direction, the side region 3O of this cut portion 3D of the outer cover formed by only one of the two continuous sheets of nonwoven material. These two portions of the 3D outer cover obtained by cutting are used to form the front outer cover and the rear outer cover of the split-type diaper, respectively.

[0073]

As the separation means, various known cutting devices can be used which are capable of continuously cutting the sheet. For example, a cutting device provided with a cutting knife on the side entering in the sheet travel direction, a cylindrical or disc-shaped cutter that has an annular knife on the circumferential surface or on the circumferential edge portion, a laser cutter, or a high-pressure water jet cutting device can be used. .

[0074]

Further, while continuously moving the two 3D outer cover pieces obtained by cutting with a predetermined gap between them, the absorbent units 2 are attached to these two pieces of the 3D outer cover piece obtained by cutting, so as to connect the 3D outer cover pieces obtained by cutting. The absorbent nodes 2 are placed on the side of the 3D cut parts of the outer cover, which is the side of the continuous inner nonwoven sheet 32S, at intervals in the direction of travel so that the absorbent nodes 2 connect the two 3D cut parts like a bridge, and so that the longitudinal the direction of each absorbent unit 2 coincided with the width direction CD.

[0075]

Thereafter, the outer, in the width direction CD, side regions 3O of the respective 3D outer cover cut portions are folded into the absorbent units 2. More specifically, when the cut portions 3D of the outer cover are moved along with the absorbent units 2 connecting them, in the direction of movement MD, the first folded portion 35A formed by folding the width direction outer side region 3O of one of the cut outer cover portions 3D covers the end regions 2A of the absorbent units 2 from the side of one end defined in the longitudinal direction. On the other hand, the second folded portion 35B formed by folding the width direction outer side region 3O of the other outer cover portion 3D obtained by cutting covers the end regions 2B of the absorbent units 2 from the other end defined in the longitudinal direction. As in the case of the embodiment described above, the folded portions 35A and 35B are secured by folding and adjusting the width of the folded portions so that (1) the portion that is in the folded portion 35A of one of the side zones and covers the end zones 2A of the absorbent units 2 with sides of one end defined in the longitudinal direction, and (2) a part that is in the folded portion 35B of the other side region and covers the end regions 2B of the absorbent units 2 from the other end defined in the longitudinal direction were formed by nonwoven fabric sheets having different properties.

[0076]

More specifically, since the outer side region 3O of at least one of the cut portions 3D of the outer cover is in a state in which one of the continuous outer nonwoven fabric sheet 31S and the continuous inner nonwoven fabric sheet 32S protrudes, or specifically , in a state in which the continuous inner nonwoven sheet 32S protrudes outward, the first folded portion 35A is fixed by bending and adjusting the width of the first folded portion 35A so that its portion that covers the end regions 2A of the absorbent units 2 from the side of one end defined in in the longitudinal direction, consisted of one of the continuous sheets 31S and 32S of nonwoven material, or consisted, in particular, of a continuous inner sheet 32S of nonwoven material. Similarly, the folded portion 35B formed by the other side region is fixed by bending and adjusting the width of the folded portion 35B so that its portion that covers the end regions 2B of the absorbent units 2 from the other end defined in the longitudinal direction is formed by two continuous sheets nonwoven material or consisted of a continuous outer sheet 31S nonwoven material. By this step, parts serving respectively as front cover part 3F and back cover part 3R of the diaper 1 are formed.

[0077]

Finally, the cut portions 3D of the outer cover together with the absorbent nodes 2 are folded in half at the portion of each absorbent node central in the width direction, and connected to each other at the locations between the absorbent nodes 2 adjacent to each other in the direction of movement MD, to form connected zones 37 therewith. Therefore, a continuous diaper 1A is formed. Thereafter, the continuous diaper 1A is cut at the connected areas 37 along the width direction of the continuous diaper 1A. Thus, parts of the connected zones 37 serve as side seams S, and pull-on disposable diapers 1 each including an outer cover 3 having two side seams S can be sequentially manufactured. A diaper made by using this manufacturing method has a front zone, a back zone and a crotch zone and includes an absorbent node placed so that it connects the front zone and a back zone, and an outer covering element located on the side of the surface of the absorbent node that is not facing the skin. The outer cover obtained by using this manufacturing method is divided into a front outer cover, which is provided on the ventral side of the wearer, and a rear outer cover, which is provided on the dorsal side of the wearer; the absorbent assembly is provided so that it connects the front and back outer covers and is attached to them, and the front outer cover and the back outer cover are connected to each other so that they form an annular shape.

[0078]

The present invention has been described above based on the preferred embodiments thereof, however, the present invention is not limited to the above described embodiments. For example, although in the above embodiments, both longitudinally end portions of the absorbent assembly are covered by only one sheet of nonwoven material, the present invention is not limited to this configuration, and in the folded portions, at least the portion that covers one of the absorbent assembly's end portions may be formed by both the outer nonwoven sheet and the inner nonwoven sheet. In this case, for reasons of effectively performing various functions of improving the feel of the diaper in use, the skin-facing surfaces of the portions covering the front end portion and the rear end portion of the absorbent assembly, respectively, are preferably formed by different sheets of nonwoven material.

[0079]

In connection with the above embodiments of the present invention, the following pull-on disposable diapers and methods for making the same are further disclosed.

<1> A pull-on disposable diaper having a front area, a back area, and a crotch area located between the front and back areas,

wherein the pull-on disposable diaper includes an absorbent assembly located in a zone extending from the front zone to the back zone, and an outer covering element located on the side of the surface of the absorbent assembly that is not facing the skin,

wherein the outer cover element includes an outer sheet of non-woven material forming a surface of the outer cover element not facing the skin, an inner sheet of non-woven material forming the surface of the outer cover element facing the skin, and an elastic element located between the outer and inner sheets of the non-woven material,

the outer cover has, in each of the front area and back area, a protrusion in which at least one of the outer sheet of nonwoven material and the inner sheet of nonwoven material protrudes outward from the edge of the waist opening, and the protruding parts are folded onto the surface facing the skin, to form folded portions covering, respectively, the front end portion and the rear end portion of the absorbent assembly, and

in the folded portions, a sheet of nonwoven fabric forming a surface that is closest to the skin and is the surface of the part covering the front end part, and a sheet of nonwoven fabric forming a surface that is closest to the skin and is the surface of the part covering the rear end part, have different properties.

[0080]

<2> A pull-on disposable diaper having a front area, a back area, and a crotch area located between the front and back areas,

wherein the pull-on disposable diaper includes an absorbent assembly located in a zone extending from the front zone to the back zone, and an outer covering element located on the side of the surface of the absorbent assembly that is not facing the skin,

wherein the outer cover element includes an outer sheet of non-woven material forming the surface of the outer cover element not facing the skin, and an inner sheet of non-woven material forming the surface of the outer cover element facing the skin,

the outer cover has, in each of the front area and back area, a protrusion in which at least one of the outer sheet of nonwoven material and the inner sheet of nonwoven material protrudes outward from the edge of the waist opening, and the protruding parts are folded onto the surface facing the skin, to form folded portions covering, respectively, the front end portion and the rear end portion of the absorbent assembly, and

in the folded portions, one of a sheet of nonwoven fabric forming a surface that is closest to the skin and is the surface of the part covering the front end part, and a sheet of nonwoven fabric forming a surface that is closest to the skin and is the surface of the part covering the back end part is an elastic nonwoven fabric and the other sheet of nonwoven fabric is a non-elastic nonwoven fabric.

<3> Pull-on disposable diaper according to item <1> or <2>,

wherein, in the folded portions, one of the portion covering the front end portion and the portion covering the rear end portion consists of an inner sheet of nonwoven material, and the other portion is formed by an outer sheet of nonwoven material and an inner sheet of nonwoven material, or consists of an outer sheet of nonwoven material.

[0081]

<4> The pull-on disposable diaper according to any one of <1> to <3>,

in which, in the folded portions, the nonwoven fabric sheet forming the surface that is closest to the skin and is the surface of the part covering the front end part has a lower stiffness than the nonwoven fabric sheet forming the surface that is closest to the skin and is the surface part covering the rear end part.

<5> The pull-on disposable diaper according to any one of <1> to <4>,

wherein in the folded portions, the nonwoven fabric sheet forming the surface that is closest to the skin and is the surface of the front end covering part has a lower warp weight than the nonwoven fabric sheet that forms the surface that is closest to the skin and is the surface of the part covering the rear end part.

<6> The pull-on disposable diaper according to any one of <1> to <5>,

wherein, in the folded portions, the nonwoven fabric sheet forming the surface that is closest to the skin and is the surface of the front end covering portion has a smaller fiber diameter than the nonwoven fabric sheet that forms the surface that is closest to the skin and is the surface part covering the rear end part.

[0082]

<7> The pull-on disposable diaper according to any one of <1> to <6>,

wherein, in the folded portions, the nonwoven fabric sheet forming a surface that is closest to the skin and is the surface of the front end covering part has a lower hydrophilicity than the nonwoven fabric sheet that forms the surface that is closest to the skin and is the surface part covering the rear end part.

<8> The pull-on disposable diaper according to any one of <1> to <7>,

wherein, in the folded portions, the nonwoven fabric sheet forming the surface that is closest to the skin and is the surface of the front end covering part has higher water resistance than the nonwoven fabric sheet forming the surface that is closest to the skin and is the surface part covering the rear end part.

<9> The pull-on disposable diaper according to any one of <1> to <8>,

in which, in the folded portions, the nonwoven fabric sheet forming a surface that is closest to the skin and is the surface of the portion covering the rear end portion has a plurality of holes.

<10> The pull-on disposable diaper according to any one of <1> to <9>,

wherein, in the folded portions, the nonwoven fabric sheet forming the surface that is closest to the skin and is the surface of the portion covering the front end portion is the inner nonwoven fabric sheet, and

in the folded portions, the nonwoven sheet forming the surface that is closest to the skin and is the surface of the portion covering the rear end portion is the outer nonwoven sheet.

[0083]

<11> The pull-on disposable diaper according to any one of <1> to <10>,

wherein in at least one of the folded portions, both the outer sheet of nonwoven material and the inner sheet of nonwoven material are folded.

<12> The pull-on disposable diaper according to any one of <1> to <11>,

wherein, in the folded portions, one of the front end portion covering portion and the rear end portion covering portion is composed of an inner nonwoven fabric sheet, and the other portion is constituted of an outer nonwoven fabric sheet.

<13> The pull-on disposable diaper according to any one of <1> to <12>,

wherein the ratio of the stiffness of the front end covering part to the stiffness of the rear end covering part is preferably 0.3 or more, and more preferably 0.4 or more, and preferably 0.8 or less, and more preferably 0.75 or less.

<14> The pull-on disposable diaper according to any one of <1> to <13>,

wherein the stiffness of the portion covering the front end portion is preferably 2 cN or more, and more preferably 3 cN or more, and preferably 6 cN or less, and more preferably 5 cN or less.

<15> The pull-on disposable diaper according to any one of <1> to <14>,

wherein the rigidity of the portion covering the rear end portion is preferably 4 cN or more, and more preferably 5 cN or more, and preferably 15 cN or less, and more preferably 13 cN or less.

[0084]

<16> The pull-on disposable diaper according to any one of <1> to <15>,

wherein the difference between the water pressure resistance provided by the front end covering portion and the water pressure resistance provided by the rear end covering portion is preferably 10 mm or more and more preferably 15 mm or more, and preferably 500 mm or less and more preferably 400 mm or less.

<17> The pull-on disposable diaper according to any one of <1> to <16>,

wherein the water pressure resistance provided by the front end covering portion is preferably 10 mm or more, and more preferably 15 mm or more, and preferably 500 mm or less, and more preferably 400 mm or less.

<18> The pull-on disposable diaper according to any one of <1> to <17>,

wherein the water pressure resistance provided by the rear end covering portion is preferably 0 mm or more, and preferably 50 mm or less, and more preferably 40 mm or less.

<19> The pull-on disposable diaper according to any one of <1> to <18>,

wherein both the rear end covering part and the front end covering part are hydrophobic, and

the difference between the hydrophilicity of the rear end covering part and the hydrophilicity of the front end covering part is preferably 15° or more and more preferably 20° or more, and preferably 90° or less and more preferably 80° or less.

[0085]

<20> The pull-on disposable diaper according to any one of <1> to <19>,

wherein both the rear end covering part and the front end covering part are hydrophobic, and

the hydrophilicity of the portion covering the front end portion is preferably 105° or more, and more preferably 110° or more, and preferably 180° or less, and more preferably 170° or less.

<21> The pull-on disposable diaper according to any one of <1> to <20>,

wherein both the rear end covering part and the front end covering part are hydrophobic, and

the hydrophilicity of the portion covering the rear end portion is preferably 90° or more, and more preferably 95° or more, and preferably 150° or less, and more preferably 145° or less.

<22> The pull-on disposable diaper according to any one of <1> to <21>,

wherein both the front end covering part and the rear end covering part are hydrophilic, and

the difference between the hydrophilicity of the front end covering part and the hydrophilicity of the rear end covering part is preferably 3 mm or more, and more preferably 5 mm or more, and preferably 100 mm or less, and more preferably 90 mm or less.

<23> The pull-on disposable diaper according to any one of <1> to <22>,

wherein both the front end covering part and the rear end covering part are hydrophilic, and

the hydrophilicity of the portion covering the front end portion is preferably 0 mm or more, and preferably 20 mm or less, and more preferably 10 mm or less.

[0086]

<24> The pull-on disposable diaper according to any one of <1> to <23>,

wherein both the front end covering part and the rear end covering part are hydrophilic, and

the hydrophilicity of the portion covering the rear end portion is preferably 3 mm or more, and more preferably 5 mm or more, and preferably 100 mm or less, and more preferably 90 mm or less.

<25> The pull-on disposable diaper according to any one of <1> to <24>,

in which the ratio of the surface weight of the base covering the front end part to the weight of the base part covering the rear end part is preferably 0.65 or more, and more preferably 0.75 or more, and preferably 0.90 or less, and more preferably 0, 85 or less.

<26> The pull-on disposable diaper according to any one of <1> to <25>,

wherein the base weight of the portion covering the front end portion is preferably 11 g/m ² or more, and more preferably 15 g/m ² or more, and preferably 25 g/m ² or less, and more preferably 20 g/m ² or less .

<27> The pull-on disposable diaper according to any one of <1> to <26>,

wherein the base weight of the portion covering the rear end portion is preferably 14 g/m ² or more, and more preferably 16 g/m ² or more, and preferably 35 g/m ² or less, and more preferably 30 g/m ² or less .

[0087]

<28> The pull-on disposable diaper according to any one of <1> to <27>,

wherein the ratio of the diameter of the fibers constituting the fiber constituting the front end covering portion to the diameter of the fibers constituting the fiber constituting the rear end covering portion is preferably 0.4 or more, and more preferably 0.5 or more, and is preferably 1.0 or less, and more preferably 0.9 or less.

<29> The pull-on disposable diaper according to any one of <1> to <28>,

wherein the diameter of the fibers constituting the fiber portion covering the front end is preferably 9 µm or more, and more preferably 10 µm or more, and preferably 20 µm or less, and more preferably 15 µm or less.

<30> The pull-on disposable diaper according to any one of <1> to <29>,

wherein the diameter of the fibers constituting the fiber portion covering the rear end portion is preferably 11 µm or more, and more preferably 13 µm or more, and preferably 22 µm or less, and more preferably 20 µm or less.

<31> The pull-on disposable diaper according to any one of <1> to <30>,

wherein the folded portion is formed by allowing only one of the outer nonwoven fabric sheet and the inner nonwoven fabric sheet to protrude outward from the edge of the waist opening to form the protrusion and fold the protrusion.

<32> The pull-on disposable diaper according to any one of <1> to <30>,

wherein the folded portion is formed by allowing both the outer nonwoven fabric sheet and the inner nonwoven fabric sheet to protrude outwardly from the edge of the waist opening to form the protrusion and fold the protrusion.

[0088]

<33> The pull-on disposable diaper according to any one of <1> to <32>,

wherein the folded portions located respectively in the front region and the rear region have different nonwoven sheet configurations.

<34> The pull-on disposable diaper according to any one of <1> to <33>,

in which the outer sheet of nonwoven fabric and the inner sheet of nonwoven fabric provided in the outer cover member differ from each other as to whether their component fibers have been subjected to hydrophilic treatment, hydrophobic treatment or the like or not, or differ in degree processing.

<35> The pull-on disposable diaper according to any one of <1> to <34>,

in which the outer sheet of nonwoven fabric and the inner sheet of nonwoven fabric provided in the outer cover member differ from each other in terms of whether hydrophilic non-bonded fibers are mixed in or not, or differ in the relative amount of fibers mixed in.

<36> The pull-on disposable diaper according to any one of <1> to <35>,

in which the part covering the front end part is formed from the inner sheet of non-woven material, and the part covering the rear end part is formed from the outer sheet of non-woven material.

<37> The pull-on disposable diaper according to any one of <1> to <36>,

wherein the inner sheet of nonwoven fabric is an elastic nonwoven fabric and forms a part that covers the front end part, and the outer sheet of nonwoven fabric is an inelastic nonwoven fabric and forms a part that covers the back end part.

[0089]

<38> The method for manufacturing the pull-on disposable diaper according to any one of <1> to <37>, the method including:

overlaying a continuous outer sheet of nonwoven material and a continuous inner sheet of nonwoven material, which move in one direction, one on top of the other to form a continuous outer cover member thereby;

placing the absorbent nodes on the side of the continuous outer cover that is the side of the continuous inner sheet of nonwoven material at intervals in the direction of movement so that the longitudinal direction of the absorbent nodes corresponds to the direction perpendicular to the direction of movement;

folding both side regions of the continuous outer cover, defined in its width direction, onto absorbent nodes;

folding the continuous outer cover with the absorbent nodes in half at the part central in the width direction, and joining the parts of the continuous outer cover, which become opposite to each other as a result of the folding in half, at the places between the absorbent nodes adjacent to each other in the direction of movement, for forming connected zones thereby and hence forming a continuous disposable diaper; and

subsequently cutting the continuous disposable diaper in the connected zones along the width direction of the continuous disposable diaper,

at the same time, at the stage of bending both side zones of the continuous outer cover element, the continuous outer cover element is bent so that the folded part of one of the side zones of the continuous outer cover element covers the end zones of the absorbent nodes from the side of one end defined in the longitudinal direction, and the folded part of the other side zones of the continuous outer cover cover the end zones of the absorbent nodes from the side of the other end defined in the longitudinal direction, and that the part that is located in the folded part of this one side zone and covers the end zones of the absorbent nodes from the side of this one end defined in the longitudinal direction, and the portion which is in the folded portion of the other side region and covers the end regions of the absorbent units from the other end defined in the longitudinal direction were formed by nonwoven fabric sheets having different properties.

<39> The method of <38>,

wherein in the step of laying the continuous outer nonwoven sheet and the continuous inner nonwoven sheet one on top of the other, two continuous nonwoven sheets are placed one on top of the other so that the two continuous nonwoven sheets form an overlapping part in their width direction, and that the continuous inner sheet of the nonwoven fabric protruded outward in the width direction from one of the side edges of this overlapping portion defined in the width direction, and

in the step of folding both side zones of the continuous outer cover, the continuous outer cover is folded so that the folded portion of this one side zone of the continuous outer cover covers the end zones of the absorbent units from the side of the given one end defined in the longitudinal direction and the folded portion of the other side zone of the continuous outer cover to cover the end regions of the absorbent nodes from the side of the other end defined in the longitudinal direction, and that the part that is located in the folded part of this one side zone and covers the end zones of the absorbent nodes from the side of this one end defined in the longitudinal direction consists from a continuous inner sheet of nonwoven material, and that the part that is in the folded part of the other side zone and covers the end zones of the absorbent units from the side of the other end defined in the longitudinal direction, was formed by two continuous or consisted of a continuous outer sheet of nonwoven fabric.

[0090]

<40> The method for manufacturing the pull-on disposable diaper according to any one of <1> to <37>, the method including:

overlaying a continuous outer sheet of nonwoven material and a continuous inner sheet of nonwoven material, which move in one direction, one on top of the other to form a continuous outer cover member thereby;

cutting the continuous outer cover in the direction of movement in a part central in its width direction, to thereby form two parts of the outer cover obtained by cutting;

placement of the absorbent knots on the side of the cut portions of the outer cover that is the side of the continuous inner sheet of nonwoven material, at intervals in the direction of travel so that the longitudinal direction of the absorbent knots corresponds to a direction perpendicular to the direction of travel and so that the absorbent knots connect the two parts obtained by cutting;

bending the outer, in the width direction, side regions of the respective cut portions of the outer cover into absorbent units;

folding the cut portions of the outer cover with the absorbent assemblies in half at a portion of each absorbent assembly centered in the width direction, and joining the cut portions of the outer cover which become opposed to each other as a result of the fold in half to each other at the locations between absorbent nodes adjacent to each other in the direction of movement, to form connected areas through this and, therefore, the formation of a continuous disposable diaper; and

subsequently cutting the continuous disposable diaper in the connected zones along the width direction of the continuous disposable diaper,

at the same time, at the stage of bending the outer side zones of the corresponding parts of the outer cover element obtained by cutting, the parts of the outer cover element obtained by cutting are bent so that the bent part of the outer side zone in the width direction of one of the parts of the outer cover element obtained by cutting covers the end zones of the absorbent nodes from the side of one end defined in the longitudinal direction, and the bent part of the outer in the width direction, the side zone of the other part of the outer covering element, obtained by cutting, covers the end zones of the absorbent nodes from the side of the other end defined in the longitudinal direction, and that part , which is located in the folded part of this one outer side zone and covers the end zones of the absorbent units from the side of this one end, defined in the longitudinal direction, and the part that is located in the folded part of the other outer side zone and covers the end zones of the absorbent nodes at the other end defined in the longitudinal direction were formed by nonwoven fabric sheets having different properties.

<41> The method according to item <40>,

wherein in the step of laying the continuous outer nonwoven sheet and the continuous inner nonwoven sheet one on top of the other, two continuous nonwoven sheets are placed one on top of the other so that the two continuous nonwoven sheets form an overlapping part in their width direction, and that one of the two the continuous sheets of nonwoven material projecting outward in the width direction from one of the side edges of the overlap portion defined in the width direction, and that the continuous inner sheet of nonwoven material extends outward in the width direction from the other side edge of the overlap portion, and

in the step of folding the outer side zones of the respective parts of the outer cover obtained by cutting, the parts of the outer cover obtained by cutting are folded so that the folded part of the outer side zone in the width direction of this one part of the outer cover obtained by cutting covers the end zones of the absorbent nodes from the side of this one end, defined in the longitudinal direction, and the bent part of the outer in the width direction, the side zone of the other part of the outer covering element, obtained by cutting, covers the end zones of the absorbent nodes from the side of the other end, defined in the longitudinal direction, and that the part, which is located in the folded part of this one outer side zone and covers the end zones of the absorbent units from the side of this one end, defined in the longitudinal direction, consists of a continuous inner sheet of nonwoven material, and that the part that is in the folded part of the other outer side zone and covers the end zones of the absorbent units from the side of the other end, defined in the longitudinal direction, was formed by two continuous sheets of nonwoven material or consisted of a continuous outer sheet of nonwoven material.

Industrial Applicability

[0091]

According to the present invention, there is provided a pull-on disposable diaper that can perform various functions on the front side and back side to improve wearing comfort.

Claims (50)

1. A pull-on disposable diaper having a front area, a back area, and a crotch area located between the front and back areas, wherein the pull-on disposable diaper includes an absorbent assembly located in a zone extending from the front zone to the back zone, and an outer covering element located on the side of the surface of the absorbent assembly that is not facing the skin, wherein the outer cover element includes an outer sheet of non-woven material forming a surface of the outer cover element not facing the skin, an inner sheet of non-woven material forming the surface of the outer cover element facing the skin, and an elastic element located between the outer and inner sheets of the non-woven material, the outer cover has, in each of the front area and the back area, a protrusion in which at least one of the outer nonwoven fabric sheet and the inner nonwoven fabric sheet protrudes outward from the edge of the waist opening, and the protrusions are folded onto a skin-facing surface, to form folded portions covering, respectively, the front end portion and the rear end portion of the absorbent assembly, and in the folded portions, the nonwoven fabric sheet forming the surface that is closest to the skin, the surface being the part covering the front end part, has a lower stiffness than the nonwoven fabric sheet forming the surface that is closest to the skin, the surface being the part covering the rear end. 2. A pull-on disposable diaper having a front area, a back area, and a crotch area located between the front and back areas, wherein the pull-on disposable diaper includes an absorbent assembly located in a zone extending from the front zone to the back zone, and an outer covering element located on the side of the surface of the absorbent assembly that is not facing the skin, wherein the outer cover element includes an outer sheet of non-woven material forming the surface of the outer cover element not facing the skin, and an inner sheet of non-woven material forming the surface of the outer cover element facing the skin, the outer cover has, in each of the front area and the back area, a protrusion in which at least one of the outer nonwoven fabric sheet and the inner nonwoven fabric sheet protrudes outward from the edge of the waist opening, and the protrusions are folded onto a skin-facing surface, to form folded portions covering, respectively, the front end portion and the rear end portion of the absorbent assembly, and in the folded portions, one of a sheet of nonwoven fabric forming a surface that is closest to the skin, the surface being a part covering the front end part, and a sheet of nonwoven fabric forming a surface that is proximate to the skin, the surface being a part covering the rear end portion is an elastic non-woven fabric; and the other sheet of non-woven fabric is a non-elastic non-woven fabric. 3. Pull-on disposable diaper according to claim 1 or 2, wherein, in the folded portions, one of the portion covering the front end portion and the portion covering the rear end portion consists of an inner sheet of nonwoven material, and the other portion is formed by an outer sheet of nonwoven material and an inner sheet of nonwoven material, or consists of an outer sheet of nonwoven material. 4. Pull-on disposable diaper according to claim 1 or 2, wherein, in the folded portions, the nonwoven sheet forming the surface that is closest to the skin, the surface being the portion covering the front end portion, has a lower warp weight than the nonwoven sheet forming the surface that is closest to the skin, the surface is the part covering the rear end part. 5. Pull-on disposable diaper according to claim 1 or 2, wherein in the folded portions, the nonwoven sheet forming the surface that is closest to the skin, the surface being the portion covering the front end portion, has a smaller fiber diameter than the nonwoven sheet forming the surface that is closest to the skin, the surface being part covering the rear end part. 6. Pull-on disposable diaper according to claim 1 or 2, wherein, in the folded portions, the nonwoven sheet forming the surface that is closest to the skin, the surface being the portion covering the front end portion, has a lower hydrophilicity than the nonwoven sheet forming the surface that is closest to the skin, the surface being part covering the rear end part. 7. Pull-on disposable diaper according to claim 1 or 2, wherein, in the folded portions, the nonwoven fabric sheet forming a surface that is proximal to the skin, the surface being the portion covering the rear end portion, has a plurality of holes. 8. Pull-on disposable diaper according to claim 1 or 2, wherein, in the folded portions, the nonwoven fabric sheet forming a surface that is closest to the skin, the surface being the portion covering the front end portion, is the inner nonwoven fabric sheet, and in the folded portions, the nonwoven fabric sheet forming the surface which is closest to the skin, the surface being the portion covering the rear end portion, is the outer nonwoven fabric sheet. 9. Pull-on disposable diaper according to claim 1 or 2, wherein in at least one of the folded portions, both the outer sheet of nonwoven material and the inner sheet of nonwoven material are folded. 10. Pull-on disposable diaper according to claim 1 or 2, wherein, in the folded portions, one of the front end covering portion and the rear end covering portion is constituted by an inner sheet of non-woven material, and the other portion is constituted by an outer sheet of non-woven material. 11. Pull-on disposable diaper according to claim 1 or 2, in which the ratio of the stiffness of the part covering the front end part to the stiffness of the part covering the rear end part is from 0.3 to 0.8. 12. Pull-on disposable diaper according to claim 1 or 2, in which the ratio of the weight of the base of the part covering the front end part to the weight of the base of the part covering the rear end part is from 0.65 to 0.90. 13. Pull-on disposable diaper according to claim 1 or 2, in which the ratio of the diameter of the fibers constituting the fibers of the part covering the front end part to the diameter of the fibers constituting the fibers of the part covering the rear end part is from 0.4 to 1.0. 14. Pull-on disposable diaper according to claim 1 or 2, wherein the inner sheet of nonwoven fabric is an elastic nonwoven fabric and forms a part that covers the front end part, and the outer sheet of nonwoven fabric is an inelastic nonwoven fabric and forms a part that covers the back end part. 15. A method for manufacturing a pull-on disposable diaper according to claim 1 or 2, the method comprising: overlaying a continuous outer sheet of nonwoven material and a continuous inner sheet of nonwoven material, which move in one direction, one on top of the other to form a continuous outer cover member thereby; placing the absorbent nodes on the side of the continuous outer cover that is the side of the continuous inner sheet of nonwoven material at intervals in the direction of movement so that the longitudinal direction of the absorbent nodes corresponds to the direction perpendicular to the direction of movement; bending both side zones of the continuous outer cover in its width direction onto absorbent nodes; folding the continuous outer cover with the absorbent nodes in half in the central part, in the width direction, and joining the parts of the continuous outer cover, which are opposite to each other as a result of the folding in half, at the places between the absorbent nodes adjacent to each other in the direction of movement, to form connected zones thereby and thus forming a continuous disposable diaper; and subsequently cutting the continuous disposable diaper in the connected zones along the width direction of the continuous disposable diaper, at the same time, at the stage of bending both side zones of the continuous outer cover element, the continuous outer cover element is bent so that the bent part of one of the side zones of the continuous outer cover element covers the end zones of the absorbent nodes from the side of one end in the longitudinal direction, and the bent part of the other side zone of the continuous of the outer cover covers the end regions of the absorbent nodes from the other end side, in the longitudinal direction, and that the part that is in the folded part of one side zone and covers the end regions of the absorbent nodes from one end in the longitudinal direction has a lower rigidity than the part , which is located in the folded part of the other side zone and covers the end zones of the absorbent nodes from the side of the other end in the longitudinal direction. 16. A method for manufacturing a pull-on disposable diaper according to claim 1 or 2, the method comprising: overlaying a continuous outer sheet of nonwoven material and a continuous inner sheet of nonwoven material, which move in one direction, one on top of the other to form a continuous outer cover member thereby; cutting the continuous outer cover in the direction of movement in the central portion in its width direction, to thereby form two parts of the outer cover obtained by cutting; arranging the absorbent knots on the side of the cut portions of the outer cover, which is the side of the continuous inner sheet of nonwoven material, at intervals in the direction of travel so that the longitudinal direction of the absorbent knots corresponds to a direction perpendicular to the direction of travel, and the absorbent knots connect the two parts, obtained by cutting; bending along the outer side zones in the direction of the width of the respective parts of the outer cover, obtained by cutting, into absorbent nodes; folding the cut portions of the outer cover with the absorbent nodes in half at the center portion of each absorbent node in the width direction, and joining the cut portions of the outer cover that are opposed to each other by the half folding to each other at the locations between the absorbent nodes , adjacent to each other in the direction of movement, to form connected zones thereby and thus form a continuous disposable diaper; and subsequently cutting the continuous disposable diaper in the connected zones along the width direction of the continuous disposable diaper, while at the step of bending the outer side zones of the respective parts of the outer cover obtained by cutting, the parts of the outer cover obtained by cutting are bent so that the bent part of the outer side zone of one of the parts of the outer cover obtained by cutting in the width direction covers the end zones absorbent nodes on one side of the longitudinal end, and the folded portion of the outer side region of the other portion of the outer cover obtained by cutting in the width direction covers the end regions of the absorbent nodes from the side of the other longitudinal end, and the part that is in the folded portion of one outer side region and covers the end zones of the absorbent nodes from one longitudinal end, has a lower rigidity than the part that is in the folded part of the other outer side zone and covers the end zones of the absorbent nodes from the other longitudinal end.

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