JP7054643B2 - Absorbent article - Google Patents

Description

The present invention relates to an absorbent article.

Patent Document 1 describes a liquid-permeable front surface sheet, a liquid-impermeable back surface sheet, an absorbent main body (main body portion) having an absorber between them, and an exterior sheet covering the back surface side of the absorbent main body. The provided absorbent article is disclosed. In addition, it was found that the suppleness of the outermost non-woven fabric among the exterior sheets has a strong influence on the suppleness of the absorbent article as a whole, and the degree of twist of the outermost non-woven fabric is 3.8 gf · cm / cm or less, which is a flexible non-woven fabric. It is disclosed that it was done.
Further, in Patent Document 1, all the non-woven fabrics constituting the exterior sheet, that is, the front-rear presser sheet covering the front-rear end of the absorbent body and the upper-layer non-woven fabric sandwiching the thread rubber together with the outermost non-woven fabric are also referred to as the outermost non-woven fabric. It is desirable to use a similar flexible non-woven fabric.

Japanese Unexamined Patent Publication No. 2010-131167

In the above case, the material arranged on the skin side of the rubber thread is only a flexible non-woven fabric. Then, the linear pressure of the rubber thread is not easily absorbed and relaxed by the non-woven fabric on the skin side, and the rubber thread is fixed to the wearer's skin with the non-woven fabric clinging around the rubber thread. Therefore, the linear pressure of the rubber thread is likely to be applied to the wearer's skin, and the marks of the rubber thread are likely to be attached to the wearer's skin. In particular, the waistline of the wearer often protrudes slightly, and rubber marks are likely to be attached to the waistline of the wearer.

Therefore, an object of the present invention is to provide an absorbent article that makes it difficult for rubber marks to be formed around the wearer's torso.

The main invention for achieving the above object has an absorbent main body having a vertical direction and a horizontal direction and having an absorbent core, and a pair of waist circumference portions, and the waist circumference portion is closest to the skin side. An absorbent article including an arranged skin-side sheet portion and a plurality of laterally stretchable thread rubbers, and the skin-side sheet portion in at least one of the pair of waist circumference portions. The flexural rigidity according to the KES method is 0.0096 N · m ² / m × 10 ^-4 or less, between the skin-side sheet portion and the thread rubber in the thickness direction of the waist circumference portion, and in the vertical direction. It is an absorbent article having an inner layer sheet portion on the waistline side of the absorbent body, and the bending rigidity of the inner layer sheet portion by the KES method is higher than the bending rigidity of the skin side sheet portion.
Other features of the present invention will be clarified by the description in the present specification and the accompanying drawings.

According to the present invention, it is possible to provide an absorbent article that makes it difficult for rubber marks to be formed around the wearer's waist.

It is a perspective view of the pants type disposable diaper 1. It is a top view of the diaper 1 in the expanded and extended state. FIG. 2 is a cross-sectional view taken along the line II of FIG. FIG. 4A is a schematic cross-sectional view of the waistline portion 40 of the comparative example cut in the thickness direction, and FIG. 4B is a schematic cross-sectional view of the waistline portion 20 of the present embodiment cut in the thickness direction. FIG. 3 is an enlarged cross-sectional view of the ventral waist circumference portion 20 shown in FIG. It is sectional drawing of the modification of the waist circumference part 20. It is sectional drawing of the modification of the waist circumference part 20. It is sectional drawing of the modification of the waist circumference part 20. It is sectional drawing of the modification of the waist circumference part 20.

The description of this specification and the accompanying drawings will clarify at least the following matters.
It has an absorbent body having a vertical direction and a horizontal direction and having an absorbent core, and a pair of waist circumference portions, wherein the waist circumference portion is a skin side seat portion arranged on the skin side most, and the said. It is an absorbent article provided with a plurality of thread rubbers that can be expanded and contracted in the lateral direction, and at least one of the pair of waist circumferences has a flexural rigidity of 0.0096 N. It is m ² / m × 10 ^-4 or less, between the skin side sheet portion and the thread rubber in the thickness direction of the waist circumference portion, and the inner layer sheet on the waist circumference side from the absorbent body in the vertical direction. It is an absorbent article having a portion and characterized in that the bending rigidity of the inner layer sheet portion by the KES method is higher than the bending rigidity of the skin side sheet portion.

According to such an absorbent article, since the flexural rigidity of the skin-side sheet portion is low, the unevenness formed on the waist circumference portion due to the shrinkage of the rubber thread is easily crushed, and gather marks are less likely to be formed on the waist circumference of the wearer. In addition, since the linear pressure of the thread rubber is absorbed and relaxed by the inner layer sheet portion, it becomes difficult for rubber marks to be formed around the wearer's waist.

In such an absorbent article, the waist circumference portion includes a non-skin side sheet portion arranged on the most non-skin side, and the thread rubber has the inner layer sheet portion and the non-skin side sheet portion in the thickness direction. The skin-side sheet portion is an absorbent article arranged between the skin and the skin-side sheet portion, wherein the end portion on the waistline side of the non-skin-side sheet portion in the vertical direction is a portion folded back toward the skin side. ..

According to such an absorbent article, the non-skin side sheet portion also has a low flexural rigidity like the skin side sheet portion, and the waistline portion from the non-skin side can be well touched by the skin.

The absorbent article is characterized in that the end portion on the waistline side of the inner layer sheet portion in the vertical direction is also folded back toward the skin side.

According to such an absorbent article, since the inner layer sheet portion arranged on the skin side of the thread rubber has two layers, rubber marks are less likely to be formed around the wearer's waist.

In such an absorbent article, the waist circumference portion includes a second inner layer sheet portion arranged on the non-skin side of the inner layer sheet portion, and a non-skin side sheet portion arranged on the most non-skin side. The flexural rigidity of the second inner layer sheet portion by the KES method is 0.0096 Nm ² / m × 10 ^-4 or less, and the thread rubber is the second inner layer sheet portion and the non-skin side sheet in the thickness direction. The skin-side sheet portion is an absorbent article arranged between the portions and the skin-side sheet portion, wherein the end portion on the waistline side of the non-skin-side sheet portion in the vertical direction is a portion folded back toward the skin side. be.

According to such an absorbent article, even when the bending rigidity of the second inner layer sheet portion is low, the linear pressure of the thread rubber is absorbed and relaxed by the inner layer sheet portion, so that rubber marks are less likely to be formed around the wearer's waist. Become.

In such an absorbent article, the waist circumference portion includes a third inner layer sheet portion arranged on the non-skin side of the inner layer sheet portion, and a non-skin side sheet portion arranged on the most non-skin side. In the vertical direction, the waistline side portion on the waistline side of the absorbent body and the core side portion overlapping the absorbent core in the thickness direction are provided, and the plurality of rubber threads are attached to the waistline side portion. It has an arranged waistline side thread rubber and a core side thread rubber arranged on the core side portion, and the waistline side thread rubber has the inner layer sheet portion and the third inner layer sheet portion in the thickness direction. The core side rubber thread is an absorbent article arranged between the third inner layer sheet portion and the non-skin side sheet portion in the thickness direction.

According to such an absorbent article, the rubber thread on the waistline side is hard to be visually recognized from the non-skin side, and the user can be given the impression that the waistline side portion fits softly. On the other hand, the rubber thread on the core side is easily visible from the non-skin side, the fit of the absorbent core is good, and the impression that it does not leak easily can be given to the user.

In such an absorbent article, the waist circumference portion has an intermediate portion between the waist circumference side portion and the core side portion in the vertical direction, and the plurality of thread rubbers are arranged in the intermediate portion. The intermediate thread rubber has the intermediate thread rubber between the inner layer sheet portion and the third inner layer sheet portion in the thickness direction, and the third inner layer sheet portion and the non-skin in the thickness direction. It is an absorbent article characterized in that it is arranged between the side sheet portion and the side sheet portion.

According to such an absorbent article, the elastic force of the intermediate portion can be increased, so that the sagging of the absorbent main body can be suppressed.

In the absorbent article, the waistline portion has a waistline side portion on the waistline side of the absorbent body in the vertical direction, and an absorbent body side portion overlapping the absorbent body in the thickness direction. The value obtained by dividing the magnitude of the force for extending the waist circumference side portion by the unit length in the lateral direction by the vertical length of the waist circumference side portion is the value obtained by dividing the absorbent body side portion in the lateral direction. It is an absorbent article characterized in that the magnitude of the force for extending by a unit length is smaller than the value obtained by dividing the magnitude of the force for extending by the unit length by the vertical length of the absorbent body side portion.

According to such an absorbent article, since the elastic force of the waist circumference side portion is smaller than that of the absorbent body side portion, gather marks and rubber marks are less likely to be attached to the waist circumference of the wearer.

In the absorbent article, in the vertical direction, the end of the inner layer sheet portion on the waist circumference side is located on the waist circumference side of the thread rubber arranged on the waist circumference side of the plurality of thread rubbers. It is an absorbent article characterized by this.

According to such an absorbent article, the inner layer sheet portion can be arranged on the skin side of more rubber threads, and rubber marks are less likely to be formed around the wearer's waist.

The absorbent article, characterized in that, in the vertical direction, the inseam-side end of the inner layer sheet portion is located on the inseam side of the waist-circumferential end of the absorbent body. Is

According to such an absorbent article, the inner layer sheet portion can be arranged on the skin side of more rubber threads, and rubber marks are less likely to be formed around the wearer's waist.

The absorbent article is characterized in that the flexural rigidity of the skin-side sheet portion by the KES method is 0.0035 N · m ² / m × 10 ^-4 or more.

According to such an absorbent article, the tensile strength of the skin-side sheet portion can be appropriately obtained, and it is possible to prevent the waistline portion from breaking during wearing.

The absorbent article is characterized in that the compression recovery rate RC of the skin-side sheet portion by the KES method is 15% or more and 50% or less.

According to such an absorbent article, the unevenness formed on the waistline portion due to the shrinkage of the rubber thread is easily crushed, and gather marks are less likely to be formed on the waistline of the wearer.

In such an absorbent article, the basis weight of the skin-side sheet portion is 10 g / m ² or more and 30 g / m ² or less, and the apparent density under a load of 49.03 hPa is 0.12 g / cm ³ or more and 0.2 g /. It is an absorbent article characterized by having a size of cm ³ or less.

According to such an absorbent article, the bending rigidity of the skin-side sheet portion can be lowered, and the flexibility can be increased.

In such an absorbent article, the skin-side sheet portion contains fibers having a fiber diameter of 14 μm or more and 22 μm or less, and the coefficient of variation MMD / MIU × 100 of the friction coefficient by the KES method is 2% or more and 6% or less. It is an absorbent article characterized by.

According to such an absorbent article, in the skin-side sheet portion, the variation in the coefficient of friction is small, the number of fibers that come into contact with the user's fingertips is relatively large, and the skin feels smooth, soft and soft. It becomes.

The absorbent article is characterized in that the friction coefficient MIU of the skin-side sheet portion is at least 0.25.

According to such an absorbent article, in the skin-side sheet portion, a relatively large number of fibers are in contact with the user's fingertips so as to cling to the fingertips, resulting in a smooth, soft and soft touch.

The absorbent article, wherein the skin-side sheet portion contains polyethylene fibers.

According to such an absorbent article, since the polyethylene fiber is more flexible than other thermoplastic resin fibers such as polypropylene fiber and PET (polyethylene terephthalate) fiber, the bending rigidity of the skin side sheet portion can be lowered. , Can increase flexibility.

=== Embodiment ===
Hereinafter, embodiments will be described with reference to an example of a pants-type disposable diaper for infants as an absorbent article according to the present invention. However, the absorbent article according to the present invention is not limited to the pants-type disposable diapers for infants, but can also be applied to pants-type disposable diapers for adults, tape-type disposable diapers, sanitary shorts and the like.

=== Configuration of pants-type disposable diaper 1 ===
FIG. 1 is a perspective view of a pants-type disposable diaper 1 (hereinafter referred to as “diaper”). FIG. 2 is a plan view of the unfolded and stretched diaper 1. FIG. 3 is a cross-sectional view taken along the line II of FIG.

In the pants-shaped state shown in FIG. 1, the diaper 1 has a vertical direction, a horizontal direction, and a front-rear direction, and a waist circumference opening BH and a pair of leg circumference openings LH are formed. In the vertical direction, the waistline side is the upper side and the inseam side is the lower side. In the anterior-posterior direction, the ventral side of the wearer is the front side and the dorsal side of the wearer is the posterior side. Further, as shown in FIG. 3, the direction in which the materials constituting the diaper 1 are laminated is referred to as the thickness direction, the side in the thickness direction that contacts the wearer is the skin side, and the side that does not contact the wearer is non. On the skin side.

Further, the diaper 1 has an absorbent main body 10 and a pair of waist circumference portions 20 and 30, which are three members having a rectangular shape in a plan view. Of the pair of waist circumferences 20 and 30, the one that is applied to the ventral side of the wearer is referred to as the ventral waist circumference portion 20, and the one that is applied to the dorsal portion of the wearer is referred to as the dorsal waist circumference portion 30.

In the unfolded diaper 1 shown in FIG. 2, the ventral waist circumference portion 20 and the dorsal waist circumference portion 30 are arranged so that their longitudinal directions are along the lateral direction of the diaper 1. Then, an end portion on one side in the longitudinal direction of the absorbent main body 10 is arranged at the central portion of the ventral waist circumference portion 20 in the lateral direction, and the longitudinal portion of the absorbent main body 10 is arranged at the central portion of the dorsal waist circumference portion 30 in the lateral direction. The end on the other side of the direction is located.

In the unfolded diaper 1 shown in FIG. 2, the absorbent body 10 is folded in half at substantially the center of the longitudinal direction so that the longitudinal direction of the absorbent body 10 is along the vertical direction of the diaper 1, and the absorbent body 10 is folded in half in the lateral direction of the diaper 1. By joining both end portions of the ventral waist circumference portion 20 and both side end portions of the dorsal waist circumference portion 30 with welding, an adhesive or the like, the diaper 1 in the pants-shaped state shown in FIG. 1 is obtained.

As shown in FIG. 3, the absorbent body 10 is arranged on the absorbent body 11, the liquid-permeable top sheet 12 arranged on the skin side of the absorbent body 11, and on the non-skin side of the absorbent body 11. It has a liquid-impermeable back sheet 13 and an exterior sheet 14 arranged on the non-skin side of the back sheet 13. The exterior sheet 14 is preferably a flexible sheet.

As shown in FIG. 2, the absorber 11 has an absorbent core 11A that absorbs and retains excrement such as urine, and a liquid-permeable core wrap sheet 11B that covers the absorbent core 11A. As the absorbent core 11A, a liquid absorbent fiber such as pulp containing a highly absorbent polymer (SAP) formed into a predetermined shape can be exemplified. The absorbent core 11A may not be covered with the core wrap sheet 11B.

Further, as shown in FIG. 2, leg circumference elastic members 15 are provided on both sides of the absorbent body 10 in the lateral direction, and the diaper 1 fits the wearer's leg circumference. The leg elastic member 15 is fixed in an extended state in the longitudinal direction of the absorbent main body 10 between the exterior sheets 14 which are folded inward in the lateral direction to form two layers, for example. Examples of the leg circumference elastic member 15 include thread rubber and elastic non-woven fabric.

As shown in FIG. 3, the ventral waist circumference portion 20 and the dorsal waist circumference portion 30 are the first sheet 21, 31 and the second sheet 22, 32, respectively, and a plurality of thread rubbers 23 that can be expanded and contracted in the lateral direction, respectively. 33 and. The plurality of rubber threads 23, 33 are arranged side by side in the vertical direction between the first sheets 21, 31 and the second sheets 22, 32, and are fixed in an extended state in the horizontal direction. Therefore, the ventral waist circumference portion 20 and the dorsal waist circumference portion 30 expand and contract laterally to fit the wearer's waist circumference. As the thread rubbers 23 and 33, various known synthetic rubbers such as styrene rubber, urethane rubber, ester rubber, polyurethane and polyethylene can be applied in addition to the thread-like natural rubber.

In the present embodiment, as a pants-type disposable diaper, a ventral waist circumference portion 20 and a dorsal waist circumference portion 30 are separated, and a so-called three-piece having three members, a ventral waist circumference portion 20, a dorsal waist circumference portion 30, and an absorbent main body 10. The type is illustrated, but it is not limited to this. For example, the ventral waist circumference 20 and the dorsal waist circumference 30 are formed of one continuous member via the lower crotch, and the ventral waist circumference portion 20 and the dorsal waist circumference portion 30 are integrated with the exterior member and absorbed. It may be a so-called two-piece type pants-type disposable diaper having two members of the sex body.

=== Characteristic parts of waist circumferences 20 and 30 ===
FIG. 4A is a schematic cross-sectional view of the waistline portion 40 of the comparative example cut in the thickness direction, and FIG. 4B is a schematic cross-sectional view of the waistline portion 20 of the present embodiment cut in the thickness direction. FIG. 5 is an enlarged view of a cross-sectional view of the ventral waist circumference portion 20 shown in FIG.

At least one of the pair of waistline portions 20 and 30 included in the diaper 1 of the present embodiment shall have a feature portion described below. Hereinafter, the ventral waist circumference portion 20 will be described as an example, but the dorsal waist circumference portion 30 may have a form that does not have the following characteristic portions. Further, both the ventral waist circumference portion 20 and the dorsal waist circumference portion 30 may have the following characteristic portions, the dorsal waist circumference portion 30 has the following feature portions, and the ventral waist circumference portion 20 has the following feature portions. It may be a form that does not have.

The ventral waist circumference portion 20 (hereinafter, also simply referred to as “girth circumference portion 20”) has a first sheet 21, a second sheet 22, and a plurality of thread rubbers 23, as described above. A part of the second seat 22 is the non-skin side seat portion 222 arranged on the non-skin side most in the waist circumference portion 20. The portion where the end portion of the second sheet 22 (non-skin side sheet portion 222) on the waist circumference side in the vertical direction is folded back toward the skin side from the absorbent main body 10 is the skin side sheet portion 221. The plurality of rubber threads 23 are arranged between the first sheet 21 and the non-skin side sheet portion 222 in the thickness direction.

The skin-side sheet portion 221 is fixed to the first sheet 21 and the absorbent main body 10 by the adhesive 50. The vertical length of the skin-side seat portion 221 is shorter than the vertical length of the non-skin-side seat portion 222, and the inseam-side end of the skin-side seat portion 221 is the end of the absorbent body 10 on the waistline side. The length should be enough to cover. By doing so, it is possible to prevent the skin-side sheet portion 221 from narrowing the absorbable area of the absorbent main body 10 without unnecessarily covering the absorbent main body 10. Further, the end portion of the absorbent main body 10 on the waist circumference side can be covered with the skin side sheet portion 221, and the opening of the end portion of the absorbent main body 10 can be suppressed.

The first sheet 21 is arranged between the skin side sheet portion 221 and the thread rubber 23 in the thickness direction, and a part of the first sheet 21 is arranged on the waist circumference side of the absorbent body 10 in the vertical direction. Has been done. Therefore, the first sheet 21 corresponds to the inner layer sheet portion. The first sheet 21 is fixed to the skin side sheet portion 221 and the absorbent main body 10 by the adhesive 50.

Further, since the skin-side seat portion 221 directly touches the wearer's skin, the seat is made flexible with low bending rigidity. By doing so, the skin-side sheet portion 221 is smooth and has a soft and soft touch, so that the skin feels good on the wearer.

Specifically, as a result of trials by the inventor, it was found that the bending rigidity of the skin-side sheet portion 221 by the KES method is preferably 0.0096 N · m ² / m × 10 ^-4 or less. Generally, the waist circumference portion 20 of the diaper 1 is provided with a thread rubber 23 that can be expanded and contracted in the lateral direction so as to fit the waist circumference of the wearer. Since the waist circumference portion 20 is contracted laterally by the thread rubber 23, unevenness in the thickness direction thereof is repeatedly formed in the waist circumference portion 20 in the lateral direction. This unevenness is long in the vertical direction, and it can be said that vertical wrinkle gathers are formed on the waist circumference portion 20.

Therefore, if the flexural rigidity of the skin-side sheet portion 221 is larger than 0.0096 Nm ² / m × 10 ^-4 and the skin-side sheet portion 221 is a strong sheet, as shown in the comparative example shown in FIG. 4A. The waist circumference portion 40 is formed with relatively large and uniform unevenness due to the shrinkage of the rubber thread 41. In addition, the shape-retaining property (repulsiveness) of the convex portion 42 protruding toward the skin side is enhanced. Therefore, when the waist circumference portion 40 comes into contact with the wearer, the convex portion 42 is less likely to be crushed, and the convex portion 42 easily bites deeply into the wearer's skin. Therefore, the wearer's skin is likely to have vertical wrinkle gather marks (compression marks by the convex portion 42).

On the other hand, in the present embodiment, the flexural rigidity of the skin-side sheet portion 221 is 0.0096 Nm ² / m × 10 ^-4 or less, and the skin-side sheet portion 221 has a high drape property and easily hangs down. And. Therefore, as shown in FIG. 4B, the waist circumference portion 20 of the present embodiment is formed with non-uniform unevenness in which fine undulations are repeated due to the shrinkage of the rubber thread 23. That is, the smoothness of the waist circumference portion 20 is good, and the contact area between the waist circumference portion 20 and the wearer's skin can be increased. Therefore, the contact pressure of the waist circumference portion 20 by the rubber thread 23 is dispersed, and it is possible to prevent the large convex portion 42 as shown in the comparative example shown in FIG. 4A from locally contacting the wearer's skin. In addition, the shape retention (repulsion) of the convex portion 26 is also lowered. Therefore, when the waistline portion 20 comes into contact with the wearer, the convex portion 26 is easily crushed, and the convex portion 26 is unlikely to bite into the wearer's skin. Therefore, it becomes difficult for the wearer's skin to have gather marks of vertical wrinkles. The skin-side sheet portion 221 may have at least one of the lateral bending rigidity and the vertical bending rigidity of 0.0096 N · m ² / m × 10 ^-4 or less, and is preferably gathered. The lateral bending rigidity, which has a large effect on formation, is preferably 0.0096 N ・ m ² / m × 10 ^-4 or less, and more preferably the bidirectional bending rigidity is 0.0096 N ・ m ² / m × 10 ^-4 . It should be as follows.

However, if the flexural rigidity of the skin-side seat portion 221 is as low as 0.0096 Nm ² / m × 10 ^-4 or less, the cushioning property of the skin-side seat portion 221 is weak. Therefore, for example, if only the skin-side sheet portion 221 is arranged on the skin side of the thread rubber 23, the linear pressure of the thread rubber 23 is difficult to be absorbed and relaxed by the skin-side sheet portion 221. Further, when the skin side sheet portion 221 has a high drape property, the skin side sheet portion 221 is clinging around the thread rubber 23, that is, the outline of the thread rubber 23 is exposed on the skin side surface of the waist circumference portion 20. , The waist circumference 20 comes into contact with the wearer's skin. Then, the linear pressure of the thread rubber 23 is likely to be applied to the wearer's skin, and rubber marks (compression marks by the thread rubber 23) are likely to be formed on the wearer's skin.

In particular, since the absorbent main body 10 is not located on the skin side of the thread rubbers 23a to 23e (hereinafter, also referred to as "girth side thread rubber") arranged on the waistline side of the absorbent body 10, the waistline side thread rubber 23a The marks of ~ 23e are easily attached to the wearer's skin. In addition, the waistline of the infant who is the target of wearing the diaper 1 of the present embodiment is often protruding. Therefore, the rubber threads 23a to 23e on the waist circumference side tend to bite into the waist circumference of the infant, and rubber marks are easily attached to the waist circumference of the infant.

Therefore, in the present embodiment, the inner layer sheet portion 21 is located between the skin side sheet portion 221 and the thread rubber 23 in the thickness direction of the waist circumference portion 20, and at least a part thereof is arranged on the waist circumference side of the absorbent main body 10. The bending rigidity by the KES method is made higher (increased) than the bending rigidity of the skin side sheet portion 221.

By doing so, the inner layer sheet portion 21 having a higher cushioning property than the skin side sheet portion 221 is arranged on the skin side of the waistline side thread rubbers 23a to 23e, and the linear pressure of the waistline side thread rubbers 23a to 23e is applied to the inner layer sheet. Absorption is relaxed in part 21. Further, since the inner layer sheet portion 21 does not easily cling to the waistline side thread rubbers 23a to 23e, the contours of the waistline side thread rubbers 23a to 23e do not easily emerge on the skin side surface of the waistline portion 20. Therefore, it is difficult for the waistline side thread rubbers 23a to 23e to bite into the wearer's waistline, and it is possible to prevent rubber marks from being formed on the wearer's waistline. It is assumed that the bending rigidity of at least one of the horizontal direction and the vertical direction of the inner layer sheet portion 21 is higher than the bending rigidity of at least one of the horizontal direction and the vertical direction of the skin side sheet portion 221.

That is, according to the diaper 1 of the present embodiment, since the wearer's waistline is less likely to have gather marks of vertical wrinkles and rubber marks are less likely to be formed, it is possible to prevent the weak skin of the infant from being injured. Further, since the inner layer sheet portion 21 is not located on the skin side most and the more flexible skin side sheet portion 221 is located on the skin side most, the skin feel to the wearer is maintained.

The flexural rigidity of the skin-side sheet portion 221 is more preferably 0.007 N · m ² / m × 10 ^-4 or less. As a result, gather marks of vertical wrinkles are less likely to be formed around the wearer's waist. Further, the bending rigidity of the inner layer sheet portion 21 is higher than 0.0096 N · m ² / m × 10 ^-4 , and more preferably 0.015 N · m ² / m × 10 ^-4 or more. Alternatively, the bending rigidity of the inner layer sheet portion 21 is more than twice the bending rigidity of the skin side sheet portion 221 or the difference between the two bending rigidity is 0.005 N · m ² / m × 10 ^-4 or more. It is also good. This makes it more difficult for rubber marks to be left around the wearer's waist.

Further, in the waist circumference portion 20 shown in FIG. 5, a part of the first sheet 21 for sandwiching and fixing the thread rubber 23 in a laterally extended state together with the second sheet 22 (non-skin side sheet portion 222) is formed as an inner layer. The seat portion 21 is used. Therefore, the configuration is simplified as compared with the case where the inner layer sheet portion 24 having high rigidity is provided separately from the first sheet 21 and the second sheet 22 that sandwich the thread rubber 23, for example, as in the waist circumference portion 20 of FIG. 7 described later. Can be changed.

Further, in the waistline portion 20 shown in FIG. 5, the portion where the end portion on the waistline side (of the non-skin side sheet portion 222) of the second sheet 22 in the vertical direction is folded back toward the skin side becomes the skin side seat portion 221. ing. Therefore, the non-skin side sheet portion 222 also has a bending rigidity of 0.0096 Nm ² / m × 10 ^-4 or less by the KES method, and is a flexible sheet, similarly to the skin side sheet portion 221. Therefore, the skin contact on the non-skin side of the waist circumference portion 20 can be improved. In particular, in the case of the diaper 1 for infants, since the guardian of the infant and the like do not wear the diaper 1, it is difficult to realize the goodness of the skin side of the waist circumference 20 on the skin side. Therefore, by improving the skin contact on the non-skin side of the waist circumference portion 20, it is possible to give the guardian of an infant or the like the impression that the diaper 1 is a product that feels good on the skin.

However, the configuration is not limited to the waist circumference portion 20 shown in FIG. For example, the skin-side sheet portion 221 and the non-skin-side sheet portion 222 may be formed of separate sheets. Further, the flexural rigidity of the non-skin side sheet portion 222 is not limited to 0.0096 N · m ² / m × 10 ^-4 or less.

The flexural rigidity of the skin-side sheet portion 221 and the inner layer sheet portion 21 can be measured by the KES method using a KES-FB2-AUTO-A bending measurement tester manufactured by Kato Tech Co., Ltd. Specifically, each of the skin side sheet portion 221 and the inner layer sheet portion 21 is cut into 10 cm × 10 cm to prepare a sample. Next, each sample is fixed between the chucks of the measuring tester so that the lateral bending rigidity can be measured in each sample. Bend up to a maximum curvature of +2.5 cm ^-1 on the front side, then bend back up to a maximum curvature of -2.5 cm ^-1 and then undo. The flexural rigidity value is the average value of the slope when the slope of the bending moment with respect to the curvature becomes almost constant for the first time to bend to the front side and the slope when the slope of the bending moment with respect to the curvature becomes almost constant for the first time to bend to the back side. calculate. Repeat 5 times for each sample, and use the average value as the flexural rigidity. The flexural rigidity of other seats, which will be described later, can be measured in the same manner.

Here, in the girth portion 20, the portion on the girth side of the absorbent main body 10 in the vertical direction is referred to as the girth side portion 20A, and the portion overlapping the absorbent main body 10 in the thickness direction is referred to as the absorbent main body side portion 20B. Further, in the absorbent body side portion 20B, the portion overlapping the absorbent core 11A in the thickness direction is referred to as the core side portion 20D, and the portion between the waist circumference side portion 20A and the core side portion 20D in the vertical direction is the intermediate portion 20C. And.

The value (F1 / L1) obtained by dividing the magnitude F1 of the force for extending the waist circumference side portion 20A by a unit length in the lateral direction by the vertical length L1 of the waist circumference side portion 20A is the absorbent body side portion 20B. Is preferably smaller than the value (F2 / L2) obtained by dividing the magnitude F2 of the force for extending the force in the lateral direction by the length L2 in the vertical direction of the absorbent main body side portion 20B.

That is, it is preferable that the lateral stretching force of the waist circumference side portion 20A per unit width in the vertical direction is smaller than the lateral stretching force of the absorbent main body side portion 20B per unit width in the vertical direction. By doing so, it is possible to suppress the tightening of the wearer's waistline by the waistline side thread rubbers 23a to 23e. Therefore, it is possible to make it more difficult for rubber marks to be formed around the wearer's waist. On the other hand, by increasing the elastic force of the absorbent main body side portion 20B, the absorbent main body 10 can be firmly brought into close contact with the wearer. Therefore, a gap is less likely to occur between the absorbent main body 10 and the wearer, and leakage of excrement can be suppressed. In addition, it is possible to suppress the sagging of the absorbent main body 10 which has increased the weight by absorbing excrement, and it is possible to maintain the fit of the absorbent main body 10.

For example, when reducing the lateral stretching force, at least one of the following may be adjusted. That is, the fineness of the rubber thread 23 is reduced (the diameter is reduced), the elongation ratio of the rubber thread 23 is lowered, the effective length of the rubber thread 23 is shortened, and the yarn per unit width in the vertical direction is reduced. It is to reduce the number of rubbers 23. The elongation ratio of the rubber thread 23 is the degree of elongation when the natural length of the rubber thread 23 is 1. The effective length of the thread rubber 23 is the length of the portion where the thread rubber 23 exhibits elasticity, and the length of the portion where the thread rubber 23 is fixed to the sheet in the stretched state. Further, when increasing the expansion / contraction force in the lateral direction, the adjustment may be performed in reverse.

Specifically, the fineness of the waistline side thread rubbers 23a to 23e is preferably about 200 to 1100 dtex, preferably about 300 to 1000 dtex. This is because if the fineness is less than 200 dtex, the required elasticity may not be exhibited, and if the fineness is larger than 1100 dtex, the thread rubber 23 is easily visible from the outside of the diaper 1, and the user has a strong impression that the waistline is tightened. This is because there is a risk. The pitch of the rubber threads 23a to 23e on the waist circumference side (the length between the centers of the rubber threads 23 adjacent to each other in the vertical direction) is about 2.0 to 12.0 mm, preferably about 4.0 to 10.0 mm. It is good. By doing so, the waistline portion 20 is fitted to the wearer, and gather marks and rubber marks are less likely to be formed on the wearer's waistline.

Further, the value (F3 / L3) obtained by dividing the magnitude F3 of the force for extending the intermediate portion 20C by the unit length in the horizontal direction by the vertical length L3 of the intermediate portion 20C is the largest, and the core side portion 20D is laterally extended. The value (F4 / L4) obtained by dividing F4, which is the magnitude of the force for extending in the direction by the unit length, by the vertical length L4 of the core side portion 20D is the next largest, and the waist circumference side portion 20A is the unit length in the lateral direction. It is preferable that the value (F1 / L1) obtained by dividing the magnitude F1 of the extending force by the vertical length L1 of the waist circumference side portion 20A is the smallest.

By doing so, it is possible to suppress the sagging of the absorbent main body 10 at the intermediate portion 20C, prevent the waist circumference side portion 20A from being tightened, and suppress the core side portion 20D from being excessively contracted in the lateral direction. Therefore, the flatness of the absorbent core 11A can be maintained, a gap is less likely to occur between the absorbent main body 10 and the wearer, and leakage of excrement can be suppressed.

It should be noted that a method of measuring the magnitudes F1 to F4 of the force for extending each portion 20A to 20D of the waist circumference portion 20 in the lateral direction by a unit length can be performed by a well-known method. For example, the target site is cut out as a sample from diaper 1. It is assumed that the sample includes all the effective length portions of the rubber threads 23 included in each portion 20A to 20D. Then, both ends of the sample corresponding to the lateral direction of the diaper 1 are sandwiched between the chucks of a tensile tester such as an autograph (AGS-G100N) manufactured by SHIMADZU. Then, the load (N) obtained in a state where the sample is stretched with the chucks separated by a unit length can be adopted as the magnitudes F1 to F4 of the force for stretching the sample in the lateral direction by the unit length.

Further, as shown in FIG. 5, in the vertical direction, the end 21a on the waist circumference side of the inner layer sheet portion 21 has a waist circumference more than the thread rubber 23a arranged on the waist circumference side among the plurality of thread rubbers 23 included in the waist circumference portion 20. It is preferably located on the side. Similarly, in the vertical direction, it is preferable that the inseam-side end 21b of the inner layer sheet portion 21 is located on the inseam side of the waist-circumferential end 10a of the absorbent body 10.

By doing so, the inner layer sheet portion 21 can be provided on the skin side of more waistline side thread rubbers 23a to 23e. Therefore, it is possible to prevent more traces of the rubber threads 23a to 23e from being left around the wearer's waist.

As in the present embodiment (FIG. 5), it is preferable that the inner layer sheet portion 21 is provided on the skin side of all the waistline side thread rubbers 23a to 23e, but the present invention is not limited to this. The inner layer sheet portion 21 may be provided between the thread rubber 23 at least one of the waistline side thread rubbers 23a to 23e and the skin side sheet portion 221.

=== Modification example of waist circumference portion 20 ===
6 to 9 are cross-sectional views of a modified example of the waist circumference portion 20.
The waist circumference portion 20 shown in FIG. 6 has the same configuration as that of FIG. 5, and the first sheet 21 fixed by sandwiching the thread rubber 23 together with the second sheet 22 (non-skin side sheet portion 222) corresponds to the inner layer sheet portion 21. However, the bending rigidity of the first sheet 21 is higher than the bending rigidity of the skin side sheet portion 221. However, in FIG. 6, the end portion 212 on the waistline side of the inner layer sheet portion 21 in the vertical direction is also folded back toward the skin side together with the second sheet 22.

Therefore, the non-folded portion 211 and the folded portion 212 of the inner layer sheet portion 21 are arranged on the skin side of the waistline side thread rubbers 23a to 23e. Therefore, the linear pressure of the waistline side thread rubbers 23a to 23e is absorbed and relaxed by the two-layer inner layer sheet portions 211 and 212. Therefore, it is difficult for the waistline side thread rubbers 23a to 23e to bite into the wearer's waistline, and it is possible to make it more difficult for rubber marks to be attached to the wearer's waistline.

In the waist circumference portion 20 shown in FIG. 7, a part of the second sheet 22 is a non-skin side seat portion 222, and a portion where the end portion of the second seat 22 on the waist circumference side is folded back is a portion. It is the skin side sheet portion 221. However, in FIG. 7, the bending rigidity (bending of at least one of the horizontal direction and the vertical direction) of the first sheet 21 which is fixed by sandwiching and fixing the rubber thread 23 together with the second sheet 22 (non-skin side sheet portion 222). Rigidity) shall be 0.0096 N ・ m ² / m × 10 ^-4 or less. That is, the first sheet 21 is a sheet as flexible as the skin side sheet portion 221 and corresponds to the second inner layer sheet portion.

Therefore, in the waistline portion 20 shown in FIG. 7, the inner layer sheet portion 24, which is a separate sheet from the first sheet 21 and the second sheet 22, is arranged between the second inner layer sheet portion 21 and the skin side sheet portion 221. Has been done. It is assumed that the bending rigidity of the inner layer sheet portion 24 is higher than the bending rigidity of the skin side sheet portion 221. Therefore, the inner layer sheet portion 24 makes it difficult for rubber marks to be formed on the wearer's skin.

In the case of the waist circumference portion 20 shown in FIG. 7, the vertical length of the inner layer sheet portion 24 having high rigidity can be made shorter than the vertical length of the first sheet 21. Specifically, it is preferable that the length is such that the waistline side thread rubbers 23a to 23e can be covered from the skin side. Therefore, in the waist circumference portion 20 shown in FIG. 7, the range in which the inner layer sheet portion 24 having high rigidity is arranged can be narrowed as compared with the waist circumference portion 20 shown in FIG. 5, and the flexibility of the waist circumference portion 20 can be increased. ..

In the waistline portion 20 shown in FIG. 8, the first sheet 21 and the second sheet 22 are located on the skin side of the first sheet 21 which is fixed by sandwiching the thread rubber 23 together with the second sheet 22 (non-skin side sheet portion 222). An inner layer sheet portion 25, which is another sheet, is arranged. The bending rigidity of the inner layer sheet portion 25 is higher than the bending rigidity of the skin side sheet portion 221. Further, the first sheet 21 corresponds to the third inner layer sheet portion 21.

In FIG. 8, the arrangement of the rubber thread 23 differs depending on the position in the vertical direction. Specifically, the waistline side thread rubbers 23a to 23e are arranged between the inner layer sheet portion 25 and the third inner layer sheet portion 21 in the thickness direction. On the other hand, the core side thread rubber 23f arranged on the core side portion 20D is arranged between the third inner layer sheet portion 21 and the non-skin side sheet portion 222 in the thickness direction. Similarly, it is preferable that the intermediate thread rubber 23 g arranged in the intermediate portion 20C is also arranged between the third inner layer sheet portion 21 and the non-skin side sheet portion 222 in the thickness direction.

In this case, since the waistline side thread rubbers 23a to 23e are arranged closer to the skin side, it is difficult to see them from the outside of the diaper 1 (from the non-skin side). Therefore, it is possible to give the user the impression that the waistline side portion 20A fits the wearer's waistline softly. On the contrary, since the core side thread rubber 23f and the intermediate thread rubber 23g are arranged on the non-skin side, they are easily visible from the outside of the diaper 1. Therefore, the fit of the absorbent core 11A and the absorbent main body 10 by the rubber thread 23 is good, and it is possible to give the user an impression that it is hard to leak.

Further, since the bending rigidity of the inner layer seat portion 25 by the KES method is higher than the bending rigidity of the skin side seat portion 221, it is possible to prevent rubber marks from being formed around the wearer's waist. In this case, in particular, the stretching force of the waist circumference side portion 20A (that is, the value obtained by dividing the magnitude of the force for extending the waist circumference side portion 20A by a unit length in the lateral direction by the vertical length of the waist circumference side portion 20A). , It is preferable to make it smaller than the other parts 20C and 20D. By doing so, the waistline side thread rubbers 23a to 23e are located closer to the skin side, but it is possible to prevent rubber marks from being formed around the waistline of the wearer.

The rigidity of the third inner layer sheet portion 21 may be higher than the flexural rigidity of the skin-side sheet portion 221 and may be lower than the flexural rigidity of the skin-side sheet portion 221. Further, although not shown, a portion where the end portion on the waistline side of the first sheet 21 is folded back may be referred to as an inner layer sheet portion (25), and a non-folded portion may be referred to as a third inner layer sheet portion (21).

In the waist circumference portion 20 shown in FIG. 9, the inner layer sheet portion 25 extends toward the inseam side as compared with the waist circumference portion 20 shown in FIG. 8, and the number of intermediate thread rubbers 23g located in the intermediate portion 20C is increased. Specifically, the intermediate thread rubber 23 g is provided between the inner layer sheet portion 25 and the third inner layer sheet portion 21 in the thickness direction, and between the third inner layer sheet portion 21 and the non-skin side sheet portion 222 in the thickness direction. It is arranged in between.

In this way, by arranging the thread rubbers 23g in the intermediate portion 20C in an overlapping manner in the thickness direction, the expansion / contraction force of the intermediate portion 20C (that is, the force for extending the intermediate portion 20C in the lateral direction by a unit length is large. The value obtained by dividing the rubber by the vertical length of the intermediate portion 20C) can be made larger than that of the other portions 20A and 20D. By doing so, it is possible to suppress the sagging of the absorbent main body 10 at the intermediate portion 20C, prevent the waist circumference side portion 20A from being tightened, and suppress the core side portion 20D from being excessively contracted in the lateral direction. Therefore, the flatness of the absorbent core 11A can be maintained, a gap is less likely to occur between the absorbent main body 10 and the wearer, and leakage of excrement can be suppressed.

=== About the flexibility of the skin side sheet part 221 ===
As described above, the skin-side sheet portion 221 has high flexibility (drapeability) in order to improve the skin contact of the waist circumference portion 20 with the wearer and to prevent the wearer's skin from having gather marks of vertical wrinkles. Use as a sheet. Hereinafter, the configuration of the skin-side sheet portion 221 will be described. It is preferable that the non-skin side sheet portion 222 also has the same flexibility.

As the skin-side sheet portion 221, a fibrous nonwoven fabric containing a thermoplastic synthetic resin, spunmelt fibrous nonwoven fabric, particularly spunbonded fibrous nonwoven fabric, and SMS (spunbond, meltblown, spunbond) fibrous nonwoven fabric are preferably used. .. Further, as the continuous fiber constituting these non-woven fabrics, polyolefin-based thermoplastic fibers containing polypropylene (PP) and polyethylene (PE), which are various known synthetic fibers, are preferably used. In this embodiment, a spunbonded non-woven fabric containing mainly polyethylene fibers is used.

Since the skin-side sheet portion 221 is formed of a spunmelt non-woven fabric made of continuous fibers, unlike an air-laid non-woven fabric containing short fibers, the free ends of the fibers do not come into direct contact with the wearer's skin. In particular, when the wearer's fingertips touch the fingerprint, the free end of the fiber does not hit the fingerprint, and since it is a continuous fiber and has a high degree of freedom, it feels soft and good to the touch so as to cling to the fingerprint of the finger. Can be given. Further, unlike the case of using a composite fiber or the like, since the fiber defibration step is not required, the number of manufacturing steps is small and the manufacturing cost can be suppressed.

By using a spunbonded non-woven fabric made of continuous fibers or an SMS fiber non-woven fabric, the skin-side sheet portion 221 has less fluffing on the sheet surface, is smoother, and is smoother than other synthetic fibers made of short fibers. , Can give a soft and soft touch. Further, the spunbonded fibrous nonwoven fabric is easier to control the fiber orientation than other fibrous nonwoven fabrics. Therefore, it is possible to obtain a well-balanced composite waist circumference portion 20 having a desired sheet tensile strength and elongation.

The skin-side sheet portion 221 is a fibrous nonwoven fabric mainly containing polyethylene fibers, and the content of the polyethylene fibers with respect to the entire sheet is 70 to 100% by mass. Since polyethylene fibers are more flexible than other thermoplastic resin fibers such as polypropylene fibers and PET (polyethylene terephthalate) fibers, the content of polyethylene fibers is at least 70% by mass, so that the content of polyethylene fibers is high. It is superior in flexibility as compared with the conventional non-woven fiber having 70% by mass or less. Further, since the polyethylene fiber has a relatively large fiber diameter, the fiber gap is relatively large and the polyethylene fiber has excellent air permeability. Therefore, the stuffiness of the waist circumference portion 20 can also be suppressed.

When the skin-side sheet portion 221 is formed of a spunbonded nonwoven fabric using continuous polyethylene fibers, the continuous fibers are heat-fused together by heat treatment by a calendar embossing method to have a plurality of fused portions. In the fused portion, each constituent fiber is heat-fused to not maintain the fiber shape, and a part of the constituent fiber is formed into a film, so that the rigidity is higher than that of the non-fused portion of each constituent fiber.

The total area ratio of the fused portion to the area of the skin side sheet portion 221 is related to the texture of the sheet and the sheet strength, but from this viewpoint, the total area ratio of the fused portion may be 5% or more and 25% or less. preferable. If the total area ratio is less than 5%, the seat strength may be low and a part of the waist circumference 20 may be torn during wearing. On the other hand, if the total area ratio exceeds 25%, the seat may be torn. May become hard as a whole and impair the texture.

Regarding the flexibility of the skin-side sheet portion 221 (specifically, "smoothness" and "soft and soft touch"), the surface characteristics, bending characteristics, fiber density, fiber diameter, etc. of the skin-side sheet portion 221. It can be confirmed by the specific volume, compression characteristics, etc.

The basis weight (mass per unit area) of the skin-side sheet portion 221 is preferably 10 g / m ² or more and 30 g / m ² or less, preferably 12 g / m ² or more and 25 g / m ² or less. Further, the thickness dimension under a slight load (0.49 hPa) is preferably 0.10 mm or more and 0.60 mm or less. When the basis weight of the skin side sheet portion 221 is less than 10 g / m ² , it is difficult to obtain sufficient tensile strength although it is excellent in flexibility, and when the basis weight exceeds 30 g / m ² , it becomes difficult to obtain sufficient tensile strength. Although relatively high tensile strength can be obtained, sufficient flexibility cannot be obtained.

The apparent density of the skin-side sheet portion 221 under a load of 0.49 hPa (≈0.5 gf / cm ² ) is 0.02 g / cm ³ or more and 0.1 g / cm ³ or less, preferably 0.04 g / cm ³ or more. It is preferably 0.08 g / cm ³ or less, and the apparent density under a load of 49.03 hPa is 0.1 g / cm ³ or more and 0.2 g / cm ³ or less, preferably 0.12 g / cm ³ or more and 0.18 g. It should be / cm ³ or less. The specific volume of the skin-side sheet portion 221 under a load of 0.49 hPa is preferably 10 cm ³ / g or more and 50 cm ³ / g or less, preferably 12.0 cm ³ / g or more and 18.0 cm ³ / g or less. The specific volume under a load of 49.03 hPa is 5.0 cm ³ / g or more and 10 cm ³ / g or less, preferably 4.0 cm ³ / g or more and 8.0 cm ³ / g or less.

When the apparent density of the skin-side sheet portion 221 under a load of 0.49 hPa is less than 0.02 g / cm ³ , the number of fused portions of the skin-side sheet portion 221 may be reduced and fluffing may be likely to occur. On the other hand, when the apparent density under a load of 0.49 hPa exceeds 0.1 g / cm ³ , the rigidity of the skin-side sheet portion 221 becomes relatively high.

The specific volume of the skin-side sheet portion 221 under a load of 49.03 hPa (≈50 gf / cm ² ) is within a predetermined range, and when the fibers are pressed by the fingertips and the fibers are compressed, they are easily crushed and have relatively high resilience. Since the density is low, the contact area between the fingertip and the fiber becomes relatively large, the fiber easily clings to the fingertip, a soft touch can be given, and gather marks are less likely to be formed.

The basis weight of the skin side sheet portion 221 was measured based on the JISL1096 method. The apparent density was obtained from the average value (N = 3) calculated by the basis weight and the thickness dimension obtained by these measurements. The specific volume of the skin-side sheet portion 221 was calculated by dividing the basis weight of the non-woven fabric by its thickness.

The average fiber diameter of the constituent fibers (mainly polyethylene fibers) of the skin-side sheet portion 221 is 14 μm or more and 22 μm or less. Since the fiber diameter is relatively large, the total area ratio of the fused portion to the area of the skin side sheet portion 221 becomes relatively small, and the bending rigidity of the skin side sheet portion 221 can be reduced.

<Bending characteristics>
As described above, the flexural rigidity of the skin-side sheet portion 221 by the KES method is 0.0096 N · m ² / m × 10 ^-4 or less. As a result, the fiber is easily bent, the contact distance between the fiber and the fingertip that touches the fiber becomes long, and the coefficient of friction MIU becomes high. However, the flexural rigidity of the skin-side sheet portion 221 based on the KES method is preferably 0.0035 N · m ² / m × 10 ^-4 or more. If the flexural rigidity is less than 0.0035 Nm ² / m × 10 ^-4 , the tensile strength of the skin-side sheet portion 221 becomes low, and a part of the waist circumference portion 20 may be broken during wearing. As a result, when the coefficient of variation of the friction coefficient MMD / MIU × 100 is 2% or more and 6% or less, the variation in the friction coefficient becomes small and smooth. That is, it is possible to increase the number of fibers clinging to the fingerprint of the fingertip and realize a smooth tactile sensation.

<Compression characteristics>
It is preferable that the compression work amount WC of the skin side sheet portion 221 based on the KES method is 0.14 N ・ m / m ² or more and 0.2 N ・ m / m ² or less, and the compression recovery rate RC is 15% or more and 50% or less. When the compression work amount WC is larger than 0.2 Nm / m ² , when the waist circumference portion 20 comes into contact with the wearer, the convex portion 26 formed by the contraction of the waist circumference portion 20 is less likely to be crushed, and the wearer's This is because it becomes easier to bite into the skin. Further, when the compression recovery rate RC is larger than 50%, when the waist circumference portion 20 comes into contact with the wearer, the crushed convex portion 26 has a strong force to return to the original state, which is local to the wearer's skin. This is because the contact pressure of the convex portion 26 becomes high. On the contrary, if the compression work amount WC is less than 0.14 Nm / m ² or the compression recovery rate RC is less than 15%, the rigidity of the waist circumference portion 20 is too low and the waist circumference portion 20 is worn. There is a risk that part of the Therefore, by setting the compression work amount WC and the compression recovery rate RC of the skin-side sheet portion 221 to the above ranges, it is possible to obtain an appropriate tensile strength of the waist circumference portion 20 and make it difficult for gather marks to be formed on the waist circumference of the wearer. Can be done.

<Surface characteristics>
The skin-side sheet portion 221 is a fiber web formed by heat-sealing continuous fibers mainly made of polyethylene fibers to each other, and since the free ends of the fibers do not exist on the surface, there is little fluffing and the sheet surface is good. It can be said that it has a smoothness. Furthermore, since polyethylene fiber is more flexible than polypropylene fiber, its surface is excellent in flexibility, and when the wearer's body moves due to deformation even under a slight load, it softly follows and fits the movement. can do.

The surface of the skin-side sheet portion 221 has a friction coefficient MIU of 0.15 or more and 0.40 or less, preferably 0.25 or more and 0.35 or less, and an average deviation MMD of friction coefficient of 0.008 or more and 0.01 or less. be. Since the coefficient of friction MIU exceeds 0.15, the frictional resistance is relatively high, and when the wearer touches the surface of the sheet, a smooth tactile sensation that clings to the skin can be given. Further, the coefficient of variation of the friction coefficient MMD / MIU × 100 is 2.0% or more and 6.0% or less. As described above, when the compression recovery coefficient RC is less than 50%, the fibers are crushed and the fiber density increases even under a slight load when the wearer's fingertips touch, and the amount of fibers in contact with the fingertips increases. The friction coefficient MIU becomes high. As a result, the coefficient of variation of the friction coefficient MMD / MIU × 100 (%) is within a relatively small predetermined value range, so that the variation in the friction coefficient is small and the user has good smoothness as a whole. The number of fibers that cling to the fingerprint of the fingertip is relatively large, and a smooth, soft and soft touch can be given.

The range of predetermined values of the bending property and the surface property of the skin side sheet portion 221 is preferably satisfied in at least one of the lateral direction and the vertical direction of the waist circumference portion 20, and preferably is satisfied in both of them. In addition, regarding each mechanical measurement based on the KES method of this specification, "Standardization and analysis of texture evaluation" 2nd edition (The Textile Machinery Society of Japan, Texture Measurement and Standardization Research Committee, July 10, 1980) Details are explained in (issued daily).

Table 1 shows the production of a plurality of non-woven fabrics under various conditions and evaluation of their characteristics and performance. The nonwoven fabrics of Examples 1 to 5 are formed of a spunbonded nonwoven fabric containing 100% by mass of polyethylene fibers which are continuous fibers, and the nonwoven fabric of Comparative Example 1 is formed of a spunbonded nonwoven fabric containing 100% by mass of polypropylene fibers which are continuous fibers. .. Further, the nonwoven fabrics of Examples 1 to 5 and Comparative Examples 1 and 2 were subjected to a calendar-type heat treatment by thermal embossing roll in the manufacturing process.

The subject was made to wear the diaper 1 having the non-woven fabrics of Examples 1 to 5 and Comparative Examples 1 to 3 as the skin side sheet portion 221 to the infant, and the ease of gathering marks and the tensile strength were examined in two steps. evaluated. Based on the skin of the infant after wearing, those that the subject felt "difficult to have gather marks" were marked with "○", and those that the subject felt "easy to have gather marks" were marked with "x". Regarding the tensile strength, the one in which the waist circumference portion 20 was broken during wearing was designated as “◯”, and the one in which the waist circumference portion 20 was not broken was designated as “x”.

<Example 1>
As the nonwoven fabric of Example 1, a spunbonded nonwoven fabric composed of polyethylene fibers having a basis weight of 20.40 g / m ² and an average fiber diameter of 14.83 μm was used.

<Example 2>
As the nonwoven fabric of Example 2, a spunbonded nonwoven fabric composed of polyethylene fibers having a basis weight of 18.98 g / m ² and an average fiber diameter of 16.89 μm was used.

<Example 3>
As the nonwoven fabric of Example 3, a spunbonded nonwoven fabric composed of polyethylene fibers having a basis weight of 20.84 g / m ² and an average fiber diameter of 20.28 μm was used.

<Example 4>
As the nonwoven fabric of Example 4, a spunbonded nonwoven fabric composed of polyethylene fibers having a basis weight of 25.12 g / m ² and an average fiber diameter of 16.77 μm was used.

<Example 5>
As the nonwoven fabric of Example 5, a spunbonded nonwoven fabric composed of polyethylene fibers having a basis weight of 15.14 g / m ² and an average fiber diameter of 16.77 μm was used.

<Comparative Example 1>
As the nonwoven fabric of Comparative Example 1, a spunbonded nonwoven fabric composed of polypropylene fibers having a basis weight of 20.37 g / m ² and an average fiber diameter of 12.19 μm was used.

<Comparative Example 2>
As the nonwoven fabric of Comparative Example 2, a spunbonded nonwoven fabric composed of composite fibers having a basis weight of 15.08 g / m ² and an average fiber diameter of 17.35 μm was used. As the composite fiber, a core-sheath type composite fiber having a core portion of polypropylene and a sheath portion of polyethylene was used as a continuous fiber.

<Comparative Example 3>
As the nonwoven fabric of Comparative Example 3, an air-through nonwoven fabric composed of composite fibers having a basis weight of 23.52 g / m ² and an average fiber diameter of 16.64 μm was used. As the composite fiber, a core-sheath type composite fiber having a fiber length of 51 mm and having a core portion of polyethylene terephthalate (PET) and a sheath portion of polyethylene was used.

The following methods were used for the measurement of the basis weight, fiber diameter, surface characteristics (MIU, MMD, MMD / MIU), bending characteristics (B), and compression characteristics (T0, Tm, WC, RC) of each non-woven fabric. ..

<Measurement method of basis weight>
Samples (N = 10) of 100 mm × 200 mm were obtained from each non-woven fabric, the basis weight of those samples was obtained, and the average value was taken as the basis weight of each nonwoven fabric.

<Measuring method of average fiber diameter>
A 10 mm × 10 mm sample was cut out from each non-woven fabric, prepared, and placed on the slide. Next, an appropriate amount of glycerin was added dropwise to each sample so that the entire sample was immersed in glycerin, and a cover glass was placed over the sample. Next, the sheet surface of the sample was observed at a magnification of 1000 times using a known optical microscope (for example, VHC-100 Digital Microscope Lens VH-Z450 manufactured by KEYENCE), and the fibers exposed on the sheet surface (N = 50). ) Was measured, and the average value was taken as the average fiber diameter.

<Measurement method of surface characteristics>
For the measurement of surface characteristics, use KES-FB4-A-AUTO (automated surface tester) manufactured by Kato Tech Co., Ltd., and place a sample in the range of 100 mm x 100 mm of each non-woven fabric on a test table on a smooth metal flat surface. I went there. Each sample is moved horizontally at a constant speed of 0.1 cm / sec by 0 to 2 cm in the mechanical direction (direction in which the fibers are oriented) at the time of manufacturing each non-woven fabric, and a friction element (measurer) having an external dimension of 5 mm × 5 mm is used. Therefore, under the condition of an initial load of 50 gf, each numerical value was calculated with the average friction coefficient in the moving section as MIU and the standard deviation of the friction coefficient at that time as MMD. The same measurement was performed 5 times for each sample, and the average was taken as the MIU and MMD values of each sample.

<Measurement method of thickness dimensions T0, Tm and compression characteristics>
A KES-FB3-AUTO-A compression tester manufactured by Kato Tech Co., Ltd. was used to measure the thickness of each non-woven fabric. First, each non-woven fabric is cut into a size of 100 mm × 100 mm to make a sample, and the center of the sample is gently sandwiched between disks located above and below, and each sample is compressed (disk area) 2.0 cm ² and 0.49 hPa. The thickness dimension T0 of is measured. Next, the measurement sample was compressed at a pressurizing speed of 0.02 mm / sec until the load was 49.03 hPa, and the thickness dimension Tm under the load of 49.03 hPa was measured. Further, the work amount (Nm / m ² ) required for compression from the thickness dimension T0 to the thickness dimension Tm is WC, and the work amount required for restoration from the thickness dimension Tm to the thickness dimension T0 is WC2. The compression recovery rate RC (%) was calculated based on the formula of.
RC (%) = WC2 / WC × 100

<Measurement result>
From the results in Table 1, when the bending rigidity of the non-woven fabric is larger than 0.0096 Nm ² / m × 10 ^-4 as in Comparative Examples 1 to 3, gather marks are likely to be formed on the wearer's skin, and Example 1 When it is 0.0096 N ・ m ² / m × 10 ^-4 or less as in ~ 5, it can be said that gather marks are less likely to be formed on the wearer's skin. Further, if the flexural rigidity is 0.0035 Nm ² / m × 10 ^-4 or more as in Example 5, the non-woven fabric of Example 5 is applied to the skin side sheet portion without breaking the waist circumference portion 20 during wearing. It can be said that it can be used as 221 without any problem.

Further, the nonwoven fabrics of Examples 1 to 5 have a lower compression recovery rate RC than the nonwoven fabrics of Comparative Examples 1 to 3 and are 50% or less. From this point as well, it can be seen that in the non-woven fabric having low bending rigidity and flexibility, the convex portions in the gathers are easily crushed and gather marks are less likely to be formed.

Further, the nonwoven fabrics of Examples 1 to 5 have a basis weight in the range of 10 g / m ² or more and 30 g / m ² or less, and an apparent density under a load of 49.03 hPa is 0.12 g / cm ³ or more and 0.2 g /. It is within the range of cm ³ or less. Therefore, it can be seen that when the basis weight and the apparent density of the nonwoven fabric are within the above ranges, flexibility can be obtained while obtaining appropriate tensile strength.

Further, when Example 1 (nonwoven fabric composed of polyethylene fibers having a fiber diameter of 14.83 μm) and Comparative Example 1 (nonwoven fabric composed of polypropylene fibers having a fiber diameter of 12.19 μm) are compared, MIU of Example 1 is compared. Is 0.335, whereas the MIU of Comparative Example 1 is 0.238, and the coefficient of fluctuation of the friction coefficient of Example 1 is MMD / MIU × 100, which is 2.57%. The coefficient of fluctuation of the friction coefficient of Example 1 MMD / MIU × 100 was 3.28%. From this, since the non-woven fabric is composed of relatively flexible polyethylene fibers, the coefficient of friction MIU becomes relatively high, and as a result, the coefficient of variation MMD / MIU × 100 of the coefficient of friction becomes low, and the coefficient of friction varies. It can be said that the coefficient is small and the sheet surface is smooth. As a result, when the user moves the fingertip in the plane direction with respect to the surface of the non-woven fabric, the amount of fibers that cling to the fingerprint is relatively large, and a smooth tactile sensation can be given.

Further, in the nonwoven fabrics of Comparative Examples 2 and 3 composed of composite fibers, the coefficient of variation MMD / MIU × 100 of the friction coefficient exceeds 6%. Therefore, it can be said that the smoothness of the sheet surface is inferior to that of the nonwoven fabrics of Examples 1 to 5 composed of single fibers of polyethylene fibers. Conversely, according to the nonwoven fabrics of Examples 1 to 5 composed of polyethylene fibers having a fiber diameter of 14 μm or more and 22 μm or less, the coefficient of variation MMD / MIU × 100 of the friction coefficient by the KES method is 2% or more and 6% or less. It can be seen that a flexible non-woven fabric having a smooth sheet surface can be easily obtained. Further, since the measurement results of the friction coefficient MIU in Examples 1, 2, 4 and 5 are 0.268 to 0.335, the friction coefficient MIU is preferably at least 0.25 (or more).

Although the embodiments of the present invention have been described above, the above-described embodiments are for facilitating the understanding of the present invention, and are not intended to limit the interpretation of the present invention. Further, the present invention can be changed or improved without departing from the spirit thereof, and it goes without saying that the present invention includes an equivalent thereof.

1 Pants-type disposable diaper (absorbent article),
10 Absorbent body,
11 Absorbent, 11A Absorbent Core, 11B Core Wrap Sheet,
12 top seats, 13 back seats, 14 exterior seats,
15 Elastic members around the legs,
20 Ventral girth (girth),
20A waist circumference side, 20B absorbent body side,
20C middle part, 20D core side part,
21 1st sheet (inner layer sheet part, 2nd inner layer sheet part, 3rd inner layer sheet part),
22 2nd sheet, 221 skin side sheet part, 222 non-skin side sheet part,
23 thread rubber, 23a-23e waistline side thread rubber,
23f core side thread rubber, 23g intermediate thread rubber,
24 Inner layer seat, 25 Inner seat, 26 Convex 30 Dorsal girth (girth), 31 First sheet,
32 2nd sheet, 33 thread rubber,
40 The waistline of the comparative example,
50 glue,

Claims (15)

It has a vertical direction and a horizontal direction,
It has an absorbent body with an absorbent core and a pair of girths.
The waist circumference portion is an absorbent article including a skin side sheet portion arranged on the skin side most and a plurality of rubber threads that can be expanded and contracted in the lateral direction.
In at least one of the pair of waist circumferences,
The flexural rigidity of the skin-side sheet portion by the KES method is 0.0096 N · m ² / m × 10 ^-4 or less.
It is between the skin side sheet portion and the thread rubber in the thickness direction of the waist circumference portion, and has an inner layer sheet portion on the waist circumference side from the absorbent body in the vertical direction.
An absorbent article characterized in that the flexural rigidity of the inner layer sheet portion by the KES method is higher than the flexural rigidity of the skin side sheet portion. The absorbent article according to claim 1.
The waistline portion includes a non-skin side seat portion arranged on the most non-skin side.
The rubber thread is arranged between the inner layer sheet portion and the non-skin side sheet portion in the thickness direction.
The skin-side sheet portion is an absorbent article characterized in that the end portion on the waistline side of the non-skin-side sheet portion in the vertical direction is a portion folded back toward the skin side. The absorbent article according to claim 2.
An absorbent article characterized in that the end portion of the inner layer sheet portion on the waistline side in the vertical direction is also folded back toward the skin side. The absorbent article according to claim 1.
The waistline portion includes a second inner layer sheet portion arranged on the non-skin side of the inner layer sheet portion, and a non-skin side sheet portion arranged on the most non-skin side.
The flexural rigidity of the second inner layer sheet portion by the KES method is 0.0096 N · m ² / m × 10 ^-4 or less.
The rubber thread is arranged between the second inner layer sheet portion and the non-skin side sheet portion in the thickness direction.
The skin-side sheet portion is an absorbent article characterized in that the end portion on the waistline side of the non-skin-side sheet portion in the vertical direction is a portion folded back toward the skin side. The absorbent article according to claim 1.
The waistline is
A third inner layer sheet portion arranged on the non-skin side of the inner layer sheet portion and a non-skin side sheet portion arranged on the most non-skin side are provided, and
In the vertical direction, it has a waistline side portion on the waistline side of the absorbent body, and a core side portion that overlaps the absorbent core in the thickness direction.
The plurality of thread rubbers include a waistline side thread rubber arranged on the waistline side portion and a core side thread rubber arranged on the core side portion.
The waistline side thread rubber is arranged between the inner layer sheet portion and the third inner layer sheet portion in the thickness direction.
The absorbent article, characterized in that the core-side thread rubber is arranged between the third inner layer sheet portion and the non-skin side sheet portion in the thickness direction. The absorbent article according to claim 5.
The waistline portion has an intermediate portion between the waistline side portion and the core side portion in the vertical direction.
The plurality of thread rubbers have an intermediate thread rubber arranged in the intermediate portion.
The intermediate thread rubber is provided between the inner layer sheet portion and the third inner layer sheet portion in the thickness direction, and between the third inner layer sheet portion and the non-skin side sheet portion in the thickness direction. , Absorbent articles characterized by being arranged respectively. The absorbent article according to any one of claims 1 to 6.
The waistline portion has a waistline side portion on the waistline side of the absorbent body in the vertical direction, and an absorbent body side portion overlapping the absorbent body in the thickness direction.
The value obtained by dividing the magnitude of the force for extending the waist circumference side portion by the unit length in the lateral direction by the vertical length of the waist circumference side portion is the unit length of the absorbent main body side portion in the lateral direction. An absorbent article characterized in that the magnitude of the stretching force is smaller than the value obtained by dividing the magnitude of the stretching force by the vertical length of the absorbent body side portion. The absorbent article according to any one of claims 1 to 7.
In the vertical direction, the end of the inner layer sheet portion on the waist circumference side is located on the waist circumference side of the thread rubber arranged on the waist circumference side of the plurality of thread rubbers. .. The absorbent article according to any one of claims 1 to 8.
An absorbent article characterized in that, in the vertical direction, the inseam-side end of the inner layer sheet portion is located on the inseam-side of the waist-circumferential end of the absorbent body. The absorbent article according to any one of claims 1 to 9.
An absorbent article characterized in that the flexural rigidity of the skin-side sheet portion by the KES method is 0.0035 N · m ² / m × 10 ^-4 or more. The absorbent article according to any one of claims 1 to 10.
An absorbent article characterized in that the compression recovery rate RC of the skin-side sheet portion by the KES method is 15% or more and 50% or less. The absorbent article according to any one of claims 1 to 11.
The basis weight of the skin-side sheet portion is 10 g / m ² or more and 30 g / m ² or less, and the apparent density under a load of 49.03 hPa is 0.12 g / cm ³ or more and 0.2 g / cm ³ or less. Absorbent article. The absorbent article according to any one of claims 1 to 12.
The skin-side sheet portion contains fibers having a fiber diameter of 14 μm or more and 22 μm or less, and is an absorbent article characterized in that the coefficient of variation MMD / MIU × 100 of the friction coefficient by the KES method is 2% or more and 6% or less. The absorbent article according to any one of claims 1 to 13.
An absorbent article having a friction coefficient MIU of the skin-side sheet portion of at least 0.25. The absorbent article according to any one of claims 1 to 14.
The skin-side sheet portion is an absorbent article characterized by containing polyethylene fibers.

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