JP4974524B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as sanitary napkins, panty liners, cage sheets, and incontinence pads.

  2. Description of the Related Art Conventionally, a technique is known in which a leak-proof groove is provided by compression processing in an absorbent layer (a laminate of a topsheet and an absorbent body) in an absorbent article such as a sanitary napkin (see, for example, Patent Document 1 below). The leak-proof groove in the sanitary napkin described in Patent Document 1 is formed by compressing the absorbent layer in the thickness direction and denting the absorbent body, and the thickness of the topsheet itself remains substantially uniform. Therefore, in the initial stage of liquid absorption, a liquid diffusion effect is achieved by taking in the liquid into the fiber structure of the absorbent body and absorbing the liquid into the water-absorbing polymer in the absorbent body.

JP-A-9-108262

  However, in the sanitary napkin described in Patent Document 1, when the liquid absorption is repeatedly performed or when a large amount of liquid absorption is performed in a short time, the fiber structure of the absorbent body is filled with liquid or water absorption is performed. When the water-soluble polymer swells, the space for diffusing the liquid disappears and the liquid diffusibility tends to be lowered.

  Therefore, the object of the present invention is to provide an absorbent article provided with a leak-proof groove by compression processing in the absorbent layer, even when liquid absorption is repeatedly performed or when a large amount of liquid absorption is performed in a short time, An object of the present invention is to provide an absorbent article having excellent diffusibility of the liquid absorbed in the absorbent layer.

  The present invention is an absorbent article having an absorbent layer formed by laminating a surface sheet made of a bulky nonwoven fabric and an absorbent sheet having low compressive deformation, and the skin contact surface side of the absorbent layer has a plan view. In the leakage prevention groove, the topsheet and the absorbent sheet are integrated by compressing the absorption layer in the thickness direction, At least the top sheet is formed by recessing, and in the top sheet, a high compression portion and a low compression portion are alternately arranged in a direction in which the leakage prevention groove extends, and the high compression portion is formed from the low compression portion. The above-mentioned object is achieved by providing an absorbent article in which a density gradient is formed toward the surface.

  According to the absorbent article of the present invention, in the absorbent article in which a leak-proof groove is provided in the absorbent layer by compression processing, when liquid absorption is repeatedly performed or when a large amount of liquid absorption is performed in a short time Moreover, the diffusibility of the liquid absorbed in the absorption layer is excellent.

Hereinafter, the absorbent article of this invention is demonstrated, referring drawings based on the sanitary napkin which is one preferable embodiment.
As shown in FIGS. 1 and 2, the sanitary napkin 1 of the present embodiment includes an absorbent layer A in which a top sheet 2 made of a bulky nonwoven fabric and an absorbent sheet 4 with low compressibility are laminated, and an absorbent layer. And a back sheet 3 disposed on the non-skin contact surface side of A.

The top sheet 2 and the back sheet 3 have the same shape in a plan view, each having a semicircular shape in the longitudinal direction and both side edges in the width direction curved inward in the width direction. The length and width are larger than those of the sheet 4.
In the present specification, unless otherwise specified, “longitudinal direction” and “width direction” mean “longitudinal direction of absorbent article” and “width direction of absorbent article”, respectively. The terms “upper surface” and “lower surface” mean “skin contact surface (side surface)” and “non-skin contact surface (side surface)”, respectively.

  The top sheet 2 covers the entire upper surface of the absorbent sheet 4, and the back sheet 3 covers the entire lower surface of the absorbent sheet 4. The top sheet 2 and the back sheet 3 extend from the longitudinal front and rear edges and the widthwise both edges of the absorbent sheet 4 in plan view. On the upper surface of the top sheet 2, a pair of side leakage prevention members 5 that form side leakage prevention walls are provided from both side edges in the width direction to both side edges in the width direction of the absorbent sheet 4.

  The top sheet 2 and the back sheet 3 extending from the longitudinal front and rear edges of the absorbent sheet 4 form an end flap F1, and are joined to each other at the longitudinal front and rear edges by the end flap F1 to form a semicircular arc. The end seal S1 is formed. The top sheet 2 and the back sheet 3 that extend from both side edges in the width direction of the absorbent sheet 4 form side flaps F2, and the side flaps F2 at the both side edges in the width direction together with the side leak-proof members 5. The side seal portion S2 that is joined and curved inward in the width direction is formed.

The longitudinal front and rear edge portions of the side leakage preventing member 5 are joined to the topsheet 2 by a leakage preventing wall seal portion S3 extending in the longitudinal direction. A pocket that is opened inward in the width direction is formed in the center portion in the longitudinal direction of the side leak-proof member 5 where the leak-proof wall seal portion S3 does not exist.
An adhesive portion (not shown) for wearing underwear is provided on the lower surface of the back sheet 3.

  The top sheet 2 is made of a bulky nonwoven fabric. Examples of the bulky nonwoven fabric include an uneven sheet composed of a first fiber layer 21 on the upper surface side and a second fiber layer 22 on the lower surface side, as shown in FIG. In this concavo-convex sheet, the first fiber layer 21 and the second fiber layer 22 are partially heat-sealed to form a heat-sealed portion (joint portion) 23. A large number of convex portions 24 having compression elasticity are formed at portions other than the fused portion 23.

The concavo-convex sheet is obtained by partially heat-sealing the first fiber layer 21 and the second fiber layer 22 made of a fiber assembly in a predetermined pattern by hot embossing, and then heat the second fiber layer 22 in the horizontal direction. Obtained by contraction.
In detail, the heat fusion by heat embossing is, for example, an embossed surface (such as a peripheral surface of an embossing roll) in which a large number of embossed spins are regularly arranged, the first fiber layer 21 and the second fiber layer 22. This is performed by melting the constituent fibers of the first fiber layer 21 and / or the second fiber layer 22 in the portion that is press-contacted to the first fiber layer 21 side of the laminated body and is thermally pressed by each pin. The heat shrinkage of the second fiber layer 22 is, for example, configured by forming the second fiber layer 22 from heat-shrinkable fibers or including the heat-shrinkable fibers in the second fiber layer 22, When the second fiber layer 22 is heat-sealed, the heat treatment is performed on the second fiber layer 22 at the same time or after both of them are heat-sealed. A large number of convex portions 24 are produced by causing the second fiber layer 22 to thermally contract in the horizontal direction and deforming the portions other than the heat fusion portion 23 in the first fiber layer 21 into a convex shape.

The large number of heat-sealing portions 23 are regularly formed in a dotted and zigzag manner, and the distance between the heat-sealing portions 23 is substantially constant.
Each convex portion 24 has a dome shape, and the inside thereof is filled with fibers constituting the first fiber layer 21. In addition, the interface between the first fiber layer 21 and the second fiber layer 22 in the portion where each convex portion 24 is formed is not bonded but is in close contact.

  It is preferable that the constituent fibers of the first fiber layer 21 have substantially no heat shrinkability or do not undergo heat shrinkage at a temperature equal to or lower than the heat shrink temperature of the constituent fibers of the second fiber layer 22 described later.

  The constituent fiber of the second fiber layer 22 is preferably made of a thermoplastic polymer material and having heat shrinkability. Moreover, it is preferable that the constituent fibers exhibit an elastomeric behavior even after shrinkage. Examples of such fibers include latently crimpable fibers. The content ratio of the latent crimpable fibers in the second fiber layer 22 is preferably 40 to 100% by weight. The latent crimpable fiber is a fiber that can be handled in the same manner as a conventional nonwoven fabric fiber before being heated, and has a property that a helical crimp is developed and contracted by heating at a predetermined temperature. is there. By using latent crimpable fibers, both heat shrinkability and elastomeric behavior can be developed simultaneously.

  The latent crimpable fiber is composed of, for example, an eccentric core-sheath type or side-by-side type composite fiber composed of two types of thermoplastic polymer materials having different shrinkage rates. Examples thereof include those described in JP-A-9-292325 and Japanese Patent No. 2759331. The second fiber layer 22 includes, for example, such latent crimpable fibers, and at the same time or after the heat fusion with the first fiber layer 21, the crimps of the fibers are expressed by heating, Shrink. Thus, the surface sheet 2 can also be formed using latent crimpable fibers as part of the constituent fibers.

  The thickness of the surface sheet 2 forms a leak-proof groove 6 having a sufficient depth (details will be described later), and forms a height difference or a density gradient at the apex of the low-compression portion 61 and the high-compression portion 62 in the leak-proof groove 6. Therefore, it is preferable to have an appropriate thickness, specifically 0.5 mm or more, and more preferably 0.5 to 2.0 mm.

The absorbent sheet 4 has absorptivity but is thin and has a very low compressive deformability with respect to compression in the thickness direction (not easily deformed even when compressed). In addition, the absorbent sheet 4 is a sheet having a rigidity such that when a large compressive force is applied, even if it is slightly recessed, the absorbent sheet 4 is not greatly recessed but is buckled and deformed before that.
Examples of such a sheet include an absorptive sheet in which water-absorbing polymer particles are dispersed in a single sheet of paper (see, for example, JP-A-8-246395). Such an absorptive sheet can be obtained, for example, by spraying water-absorbing polymer particles on a wet-fabricated wet fiber web, overlaying paper on it, and drying and integrating them.

Moreover, as the absorptive sheet 4, the absorptive sheet which compounded the constituent fiber and the polymerizable water-absorbing polymer using polymerization (for example, refer to JP-A-11-93073) can be mentioned. Such an absorbent sheet can be obtained, for example, by attaching a liquid material containing a polymerizable water-absorbing polymer to non-molded fibers and polymerizing them.
Moreover, the absorptive sheet 4 can be formed by sandwiching a water-absorbing polymer between two sheets of paper or non-woven fabric, or between folded paper or non-woven fabric, and pressing and integrating the whole.

As the water absorbent polymer, various water absorbent polymers suitable for the method of forming the absorbent sheet 4 can be used.
The content of the water-absorbing polymer in the absorbent sheet 4 below the leak-proof groove 6 (details will be described later) is preferably 25% or more, and more preferably 30% or more. This content is based on mass. A high content of the water-absorbing polymer is preferable in that the compressive deformability of the entire absorbent sheet 4 is lowered.

There is no restriction | limiting in particular as the back surface sheet 3, In this embodiment, the leak-proof film sheet is used.
Examples of the side leak-proof member 5 include a nonwoven fabric, a film sheet, paper, and the like, and a hydrophobic nonwoven fabric that is liquid-impermeable or hardly permeable, a leak-proof film sheet, and the like are preferably used from the viewpoint of leak-proof properties. In this embodiment, a hydrophobic nonwoven fabric is used.

  On the skin contact surface side of the absorbent layer A, as shown in FIG. 1, a leak-proof groove 6 extending in a continuous line shape in a plan view is provided. The plan view shape of the leak-proof groove 6 in the present embodiment is an annular shape, specifically a land track shape (annular shape formed by connecting a semicircular arc curve to a pair of parallel straight lines). The position of the leak-proof groove 6 in the present embodiment is the central portion in the longitudinal direction in the region between the pair of side leak-proof members 5 and 5. The width of the leak-proof groove 6 is preferably 0.5 to 5.0 mm.

  As shown in FIG. 2, the top sheet 2 and the absorbent sheet 4 are joined by a leak-proof groove 6. Specifically, the leak-proof groove 6 is formed by compressing the absorbent layer A in the thickness direction so that the topsheet 2 and the absorbent sheet 4 are integrated and at least the topsheet 2 is recessed. Yes. And in the surface sheet 2, the high compression part 62 and the low compression part 61 are alternately arranged in the direction where the leak-proof groove 6 extends, and the density gradient is formed toward the high compression part 62 from the low compression part 61. Yes.

  The form of integration of the surface sheet 2 and the absorbent sheet 4 varies depending on the material, the integration method, and the like, but is, for example, fusion, pressure bonding, or fiber entanglement.

  The low compression portion 61 is a portion compressed by a low stress, and the high compression portion 62 is a portion compressed by a high stress. Therefore, the height of the apex of the low compression portion 61 is higher than the height of the apex of the high compression portion 62, and the bottom of the leak-proof groove 6 is uneven in the extending direction of the leak-proof groove 6. Yes. Further, the fiber density of the low compression portion 61 is sparser (lower) than the fiber density of the high compression portion 62, and a density gradient is formed from the low compression portion 61 toward the high compression portion 62. . The fiber density of the high compression part 62 is 1.5 times or more with respect to the fiber density of the low compression part 61, desirably 2.0 times or more.

  When the absorbent layer A is compressed in the thickness direction, the topsheet 2 made of a bulky nonwoven fabric is easily recessed and plastically deformed in that state. On the other hand, the absorbent sheet 4 with low compressive deformation is not substantially recessed, or the portion located below the high compression portion 62 is recessed discontinuously (intermittently) in the direction in which the leak-proof groove 6 extends. To plastically deform.

Specifically, as shown in FIG. 2A, only the topsheet 2 is formed in the leak-proof groove 6 so as to be recessed, and the topsheet 2 and the absorption as shown in FIG. There is a form in which both of the conductive sheets 4 are recessed.
In the leak-proof groove 6 in which only the top sheet 2 shown in FIG. 2A is recessed, the absorbent sheet 4 on the lower side of the high-compression portion 62 of the leak-proof groove 6 is not easily perforated during compression processing. Moreover, the surface sheet 2 is difficult to be formed into a film at the time of compression processing.

In the leak-proof groove 6 in which both the top sheet 2 and the absorbent sheet 4 shown in FIG. 2B are recessed, the top sheet 2 that forms the high compression portion 62 of the leak-proof groove 6 has a high stress. Although it may be formed into a film because it is compressed, the liquid flowing into the high compression part 62 is absorbed by the absorbent sheet 4 via the low compression part 61.
The leak-proof groove 6 may be formed only in the form shown in FIG. 2A or only in the form shown in FIG. 2B in the entire absorbent article, and both forms are formed in a mixed manner. Good.

Depth of the leak-proof groove 6 (height difference between the top of the topsheet 2 and the top of the high compression portion 62) H1 is preferably 0.5 to 5.0 mm, more preferably 1.0 to 4.0 mm. .
The height difference H2 between the apex of the low compression portion 61 and the apex of the high compression portion 62 is preferably 0.25 to 2.5 mm, more preferably 0.5 to 2.0 mm.

  There is a particular limitation on the method of forming the leak-proof groove 6 that is necessarily recessed in the surface sheet 2 and that is not recessed in the absorbent sheet 4 or is discontinuously recessed in the direction in which the leak-proof groove 6 extends. For example, the following method may be mentioned.

  A pressing roll (not shown) provided with a pressing portion having an uneven shape corresponding to the shape of the low compression portion 61 and the high compression portion 62 of the leakage preventing groove 6 is used. The surface side of the absorption layer A in which the leak-proof groove 6 is not formed is pressed with the pressing roll and heat-sealed. Here, in order to form the leak-proof grooves 6 in which the high compression portions 62 and the low compression portions 61 are alternately arranged on the top sheet 2, the processing conditions may be set appropriately. Particularly important conditions are the shape of the pressing part (height, width, uneven shape, etc.), pressing pressure, heating temperature (heat seal temperature), and pressing time.

In the sanitary napkin 1 of the present embodiment, the absorbent layer A is formed by laminating a surface sheet 2 made of a bulky nonwoven fabric and an absorbent sheet 4 having low compressive deformation. Therefore, when the absorbent layer A is compressed in the thickness direction and the topsheet 2 and the absorbent sheet 4 are integrated, the topsheet 2 is easily dented and plastically deformed, and all the continuous linear leak-proof grooves 6 [ Form shown in FIG. 2A] or a part [form shown in FIG. 2B] is formed. On the other hand, since the absorbent sheet 4 has low compressive deformability, even if the topsheet 2 is easily recessed by compressing the absorbent layer A, it is not substantially recessed (the form shown in FIG. 2 (a)), Indented discontinuously (intermittently) in the extending direction of the leak-proof groove 6 and plastically deformed (form shown in FIG. 2B).
As a result, the surface sheet 2 is necessarily recessed, and the absorbent sheet 4 is not substantially recessed or the leakage prevention groove 6 is recessed in a discontinuous manner in the direction in which the leakage prevention groove 6 extends. Then, the leakage prevention grooves 6 in which the high compression portions 62 and the low compression portions 61 are alternately arranged and a density gradient is formed from the low compression portions 61 toward the high compression portions 62 are formed.

According to the sanitary napkin 1 of the present embodiment configured as described above, the high compression portion 62 and the low compression portion 61 are alternately arranged in the surface sheet 2 in the direction in which the leakage prevention groove 6 extends, and the low compression A dense gradient is formed from the portion 61 toward the high compression portion 62. Therefore, the liquid that has flowed into the leakage preventing groove 6 moves from the low compression portion 61 toward the high compression portion 62 due to the capillary force based on the density gradient between the low compression portion 61 and the high compression portion 62, and absorbs the liquid. It is efficiently guided to the sheet 4.
Therefore, the feeling of wetness given to the wearer's skin is reduced, and a comfortable feeling of use continues for a long time. Therefore, even when liquid absorption is repeated or when a large amount of liquid absorption is performed in a short time, the diffusibility of the liquid absorbed in the absorption layer is excellent.

Further, since the direction of the flow of the liquid is expressed along the direction in which the leakage preventing groove 6 extends, the liquid is difficult to leak outside the annular leakage preventing groove 6.
When the uneven sheet shown in FIG. 3 is used as the top sheet 2, the lower second fiber layer 22, which is a contact layer with the absorbent sheet 4, is difficult to be fused to the absorbent sheet 4. Therefore, since a diffusion path exists in the lower layer (second fiber layer 22) of the surface sheet 2, the diffusibility in the liquid surface direction (direction perpendicular to the thickness direction) is high.

The absorbent article of the present invention is not limited to the above embodiment, and can be appropriately changed without departing from the gist of the present invention.
For example, as shown in FIG. 4, another leak-proof groove 6 ′ extending in the longitudinal direction of the absorbent article (sanitary napkin) 1 is provided inside the annular leak-proof groove 6 in the width direction of the absorbent article 1. A plurality may be provided apart from each other. In the embodiment shown in FIG. 4, two leak-proof grooves 6 ′ extending linearly in the longitudinal direction of the sanitary napkin 1 are provided. As described above, according to the embodiment in which the leakage preventing groove 6 ′ extending in the longitudinal direction is provided inside the annular leakage preventing groove 6, the diffusibility of the liquid in the longitudinal direction is provided inside the annular leakage preventing groove 6. It is preferable in terms of further improvement.

The planar view shape of the leak-proof groove is not limited to an annular shape, and may be a linear shape or a curved shape extending in the longitudinal direction of the absorbent article, or a linear shape or a curved shape extending in the width direction of the absorbent article.
In addition to sanitary napkins, the absorbent article of the present invention can also be applied to panty liners, cage sheets, incontinence pads, and the like.

FIG. 1 is a plan view showing a sanitary napkin which is an embodiment of the absorbent article of the present invention. 2 is a cross-sectional view taken along the line II-II shown in FIG. 3A and 3B are views showing a surface sheet of the sanitary napkin shown in FIG. 1, wherein FIG. 3A is a longitudinal sectional perspective view, and FIG. 3B is a sectional view taken along the line B-B shown in FIG. FIG. 4 is a plan view showing a sanitary napkin according to another embodiment.

Explanation of symbols

1 Sanitary napkin (absorbent article)
2 Top sheet 3 Back sheet 4 Absorbent sheet 5 Side leak-proof member 6 Leak-proof groove 61 Low compression part 62 High compression part

Claims (4)

An absorbent article having an absorbent layer formed by laminating a surface sheet having a thickness of 0.5 mm or more made of a bulky nonwoven fabric and an absorbent sheet having low compressive deformation,
On the skin contact surface side of the absorbent layer, a leak-proof groove extending in a continuous line shape in plan view is provided,
The leak-proof groove is formed by compressing the absorbent layer in the thickness direction so that the topsheet and the absorbent sheet are integrated, and at least the topsheet is recessed and plastically deformed in that state. Formed,
In the surface sheet, a high compression portion and a low compression portion are alternately arranged in the extending direction of the leakage prevention groove, and a dense gradient is formed from the low compression portion toward the high compression portion,
The absorbent sheet is substantially not recessed at the site where the leakage preventing groove is formed, or is discontinuously recessed in the extending direction of the leakage preventing groove ,
The absorptive article whose content rate of the water-absorbent polymer in the absorptive sheet in the lower part of the leak-proof groove is 25% or more .   2. The surface sheet is made of a thermoplastic polymer material, and is configured to include latent crimpable fibers having heat shrinkability that causes a helical crimp to shrink when heated at a predetermined temperature. The absorbent article as described. The absorbent article according to claim 1 or 2 , wherein the leakage prevention groove has an annular shape in plan view. The absorbent article according to claim 3 , wherein a plurality of other leakage prevention grooves extending in the longitudinal direction of the absorbent article are provided inside the annular leakage prevention groove and spaced apart in the width direction of the absorbent article. .

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