JP4090411B2 - Absorbent article surface sheet - Google Patents

Description

  The present invention relates to an absorbent article such as a sanitary napkin, a panty liner, an incontinence pad, a disposable diaper, and a surface sheet preferably used for a skin contact surface thereof.

  A surface sheet of an absorbent article such as a sanitary napkin or a disposable diaper is required to smoothly transfer discharge from the human body such as menstrual blood or urine to the absorbent body.

  As a surface sheet of an absorbent article, a non-woven surface sheet comprising an upper layer disposed on the skin side and a lower layer disposed on the absorber side, wherein the gap between the constituent fibers of the lower layer is defined as the gap between the constituent fibers of the upper layer A surface sheet has been proposed in which the transferability of the liquid from the upper layer to the lower layer is enhanced by making it smaller (see Patent Document 1).

  However, the level of leakage prevention performance, absorption performance, etc. required for products (absorbent articles) has been improving year by year, and depending on the above-mentioned surface sheet, there are cases where such demands cannot be fully met. Can happen.

  Moreover, the surface sheet which integrates the upper layer distribute | arranged to the skin side and the lower layer distribute | arranged to the absorber side by the embossing (debossing pattern) in the thickness direction is also proposed (refer patent document 2). However, even this surface sheet cannot meet various demands in recent years.

JP 7-178133 A JP-A-10-272152

  The object of the present invention is to be able to smoothly guide the liquid supplied on the top sheet to the absorber, and to prevent discomfort and stuffiness due to the liquid remaining on the surface layer, leakage due to the liquid flowing on the surface, etc. It is providing the surface sheet which can be prevented automatically, and an absorbent article using the same.

  The present invention comprises a laminated nonwoven fabric having an upper layer disposed on the skin side and a lower layer disposed on the absorber side, and a plurality of sheet compression portions formed by integrally compressing the upper layer and the lower layer, and the sheet compression And a lower layer compression part formed by compressing only the lower layer, the minimum density of the portion other than the sheet compression part and the lower layer compression part in the lower layer, the upper layer, The object is achieved by providing a surface sheet of an absorbent article that is equal to or higher than the minimum density of parts other than the sheet compression part (hereinafter referred to as the present invention when referred to as the first invention).

  The present invention is an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent interposed between the two sheets. A multi-layer nonwoven fabric having an upper layer disposed on the side and a lower layer disposed on the absorber side, the upper layer and the lower layer being integrally compressed, and located between the sheet compression portions A lower layer compression part formed by compressing only the lower layer, and the minimum density of parts other than the sheet compression part and the lower layer compression part in the lower layer is other than the sheet compression part in the upper layer. The object is achieved by providing an absorbent article having a density equal to or higher than the minimum density of the portion (hereinafter referred to as this invention when referred to as the second invention).

  The present invention is an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent interposed between the two sheets, and has a substantially vertically long shape. The top sheet is made of a laminated non-woven fabric having an upper layer disposed on the skin side and a lower layer disposed on the absorber side, and the upper layer and the lower layer are integrally compressed to form a large number of sheets. It has a compression part and a lower layer compression part which is located between the sheet compression parts and is formed by compressing only the lower layer, and the topsheet is on both sides in the longitudinal direction of the absorbent article, Only the upper layer has a single layer portion formed by extending, and the portion of the topsheet having a two-layer structure in which the upper layer and the lower layer are laminated is a central region in the width direction of the absorbent article. The absorber is coated in the central region. In both sides of the one in which the single layer portion has achieved the above object by providing an absorbent article that covers the absorber (hereinafter, when referred to as a third invention refers to the present invention).

  According to the surface sheet of the absorbent article of the first invention, the liquid supplied on the surface sheet can be smoothly guided to the absorbent body, and the liquid remains on the surface layer. It is possible to effectively prevent leakage and the like due to flowing through the.

  According to the absorbent article of the second invention, the liquid supplied on the top sheet can be smoothly guided to the absorber, causing discomfort and stuffiness due to the liquid remaining on the surface layer, and the liquid flowing on the surface. It is possible to effectively prevent leakage and the like.

  According to the absorbent article of the third invention, the liquid transfer to the absorber can be concentrated in the central region, and the diffusion of the liquid to both sides of the central region can be suppressed, and the leakage prevention property and the like are excellent. . Moreover, since a good cushioning property is obtained in the central region, the fitting property and the like are excellent.

The present invention will be described below based on preferred embodiments with reference to the drawings.
A sanitary napkin 1 shown in FIG. 1 and FIG. 2 is an embodiment of the absorbent article of the present invention. The surface sheet 2 as an embodiment of the surface sheet of the absorbent article of the present invention is liquid-impermeable. A back sheet 3 and a liquid-retaining absorbent 4 interposed between these two sheets are provided and are formed substantially vertically long.

  The top sheet 2 has a size larger than that of the absorbent body 4, and both side edges in the longitudinal direction are bonded to the back sheet 3 on the non-skin contact surface side of the absorbent body 4, The outer body 4 extends outward from the front and rear ends of the absorber 4 and is joined to the back sheet 3 at the extended portion. A liquid-impermeable leak-proof sheet 5 is disposed between the absorbent body 4 and the back sheet 3, and both side edges of the leak-proof sheet 5 cover both side parts of the absorbent body 4, thereby absorbing the absorbent body. 4 is located on the skin contact surface side. As the back sheet 3 and the absorbent body 4, materials usually used for this type of absorbent article can be used without particular limitation. As the leak-proof sheet 5, a film made of an olefin resin such as polypropylene or polyethylene, a sheet obtained by laminating the film and paper, a water-repellent nonwoven fabric, or the like is preferably used.

  As shown in FIGS. 2 and 3, the top sheet 2 is made of a laminated nonwoven fabric having an upper layer 21 disposed on the skin side and a lower layer 22 disposed on the absorber 4 side. The topsheet 2 of the present embodiment has a longitudinal direction and a width direction, and as shown in FIGS. 1 and 2, has a single layer portion 25 composed of only the upper layer 21 on both sides in the longitudinal direction. ing.

The topsheet 2 has a portion 20 (hereinafter also referred to as a two-layer structure portion) having a two-layer structure in which an upper layer 21 and a lower layer 22 are laminated in a state in which the longitudinal direction thereof coincides with the longitudinal direction of the sanitary napkin 1. The absorbent body 4 is covered in the center region (portion indicated by hatching in FIG. 1) of the sanitary napkin 1 in the width direction, and the single layer portion 25 composed only of the upper layer 21 is formed on both sides of the central region. Is covered.
With such a configuration, the sanitary napkin 1 can concentrate the liquid transfer to the absorber in the central region and can suppress the diffusion of the liquid to both sides of the central region. Excellent blood spread prevention. Moreover, since a good cushioning property is obtained in the central region, the fitting property and the like are excellent.

  In the surface sheet 2 according to the present embodiment, both side edges 26 and 26 are bonded and fixed between the absorbent body 4 and the back sheet 3 at both sides in the longitudinal direction of the sanitary napkin 1. The end portions 27 are fixed to the back sheet 3 extending from the end edge of the absorbent body 4 by known joining means at both ends in the longitudinal direction of the sanitary napkin 1.

  As shown in FIG. 3, the top sheet 2 is positioned between a large number of sheet compression portions 23 formed by the upper layer 21 and the lower layer 22 being integrally compressed in the thickness direction, and the sheet compression portions 23, 23, It has the lower layer compression part 24 formed by compressing only the lower layer 22.

The upper layer 21 and the lower layer 22 are both made of a fiber assembly. The fiber assembly here is a concept including a nonwoven fabric obtained by various production methods and a fiber web obtained by a carding machine before being made into a nonwoven fabric.
Then, the upper layer 21 and the lower layer 22 are laminated in a state where a fiber assembly for forming the upper layer 21 and a fiber assembly for forming the lower layer 22 are stacked on each other. They are integrated in the thickness direction by embossing such as sonic embossing in a predetermined pattern.

The sheet compression part 23 is a compression part formed by this embossing, and the thickness between the surface on the skin side and the surface on the absorber side is integrally compressed, and the thickness is smaller than other parts in the surface sheet 2. It has become.
In the sheet compression section 23, the upper constituent fibers, the upper constituent fibers and the lower constituent fibers, and the lower constituent fibers are heat-bonded to each other by heat applied during embossing.

  FIG. 4A is a diagram illustrating an arrangement pattern of the sheet compression unit 23 in the present embodiment. The sheet compression units 23 in the present embodiment are circular and distributed in a large number of scattered points, and each of the sheet compression units 23 is the other six sheet compression units 23 having the same distance from the compression unit 23. The six sheet compression portions 23 are arranged so as to form a regular hexagon.

Moreover, the surface sheet 2 has many lower layer compression parts 24 formed by compressing only the lower layer 22. Prior to laminating the fiber assembly for forming the upper layer 21 and the fiber assembly for forming the lower layer 22, the lower layer compression unit 24 applies only heat embossing, super It is formed by applying embossing such as sonic embossing in a predetermined pattern.
In the lower layer compression part 24, the constituent fibers of the lower layer are thermally fused to each other by heat applied during embossing. In the lower layer, the lower layer compression portion 24 has a smaller thickness than other portions that are not compressed.

  FIG. 4B is a diagram showing an arrangement pattern of the lower layer compression unit 24 in the present embodiment, and is the same scale as FIG. The lower layer compression parts 24 in this embodiment are circularly arranged in a large number of scattered points, and each lower layer compression part 24 is surrounded by six solid lower layer compression parts 24 having the same distance from the compression part 24. The six lower layer compression parts 24 are arranged so as to form a regular hexagon.

  In addition, the expression that the lower layer compression unit is located between the sheet compression units includes three or more lower layer compression units in addition to the case where one or more lower layer compression units exist on a straight line connecting two adjacent sheet compression units. This includes the case where one or more lower layer compression portions always exist in a polygonal region formed by the sheet compression portion (polygon having a sheet compression portion at each corner). In the present embodiment, there are a plurality of (about 3 to 6) lower layer compression sections 24 in a triangular region formed by three sheet compression sections.

The top sheet 2 of the present embodiment has a minimum density ρ2 of a portion other than the sheet compression portion 23 and the lower layer compression portion 24 in the lower layer 22, that is, a substantially uncompressed portion (hereinafter referred to as a lower layer non-compression portion) 29. In the upper layer 21, the density is equal to or higher than the minimum density ρ1 of a portion other than the sheet compression portion 23 (hereinafter referred to as a sheet non-compression portion) 28. From the viewpoint of improving the liquid transferability, in particular the liquid transferability in the thickness direction, the minimum density ρ2 of the lower layer non-compressed portion 29 is preferably higher than the minimum density ρ1 of the sheet non-compressed portion 28, and particularly the minimum density. The ratio (ρ2 / ρ1) is preferably 1.1-10. Incidentally, it is preferable that the minimum density ρ2 of the lower non-compression part 29 is 0.01~0.2g / cm ^3, the minimum density ρ1 of the sheet non-compressed portion 28 is 0.001 to 0.1 g / cm ³ It is preferable.

Here, the minimum densities ρ1 and ρ2 of the sheet uncompressed portion 28 and the lower layer uncompressed portion 29 can be measured as follows.
Calculated from the thickness of each layer and the weight (basis weight) per unit area. The thickness of each layer is cut on a straight line passing through the two sheet compression parts 23 or the two lower layer compression parts 24 without applying pressure with a cutter or the like, and the sheet uncompressed part 28 and the lower layer uncompressed part 29 Measure the thickness. In the thickness measurement, the thickness of the maximum thickness portion of the upper sheet uncompressed portion 28 and the lower layer uncompressed portion 29 is measured using a digital HF microscope (model VH8000) manufactured by KEYENCE. The weight (basis weight) per unit area of each layer is measured by peeling off the upper layer and the lower layer.
The density is calculated by the following formula. Density ρ = basis weight / thickness

Further, from the viewpoint of increasing the apparent density of the lower layer non-compressed portion 29 and improving the transferability of the liquid from the upper layer 21 to the lower layer 22, the arrangement pitch P2 of the lower layer compressed portion 24 [see FIG. It is preferably smaller than the arrangement pitch P1 of the portion 23 [see FIG. 4A], and the arrangement pitch ratio (P2 / P1) is more preferably 0.1 to 0.7.
The arrangement pitch of the sheet compression unit 23 and the lower layer compression unit 24 is the distance between the center points of the two closest compression units when a large number of dot-shaped compression units are arranged in a distributed manner. When many linear compression parts are arrange | positioned in parallel, it is the shortest distance between the center lines (line | wire which bisects a width | variety) of each two adjacent compression parts.

  In addition, the shape of each compression part when many dot-shaped compression parts 23 and 24 are arranged in a dispersed manner can be an arbitrary shape such as an ellipse, a triangle, a quadrangle, a rhombus, and a heart shape in addition to a circle. Both the compression parts 23 and 24 are preferably in the form of dots that are discontinuous in both the longitudinal direction and the width direction of the surface sheet, but are continuous linear in the longitudinal direction or the width direction of the surface sheet. May be. It is preferable that the dot-shaped compression parts 23 and 24 are uniformly distributed over the entire two-layer structure portion 20 of the sheet.

  From the viewpoint of increasing the apparent density of the lower layer non-compressed portion 29 and improving the transferability of the liquid from the upper layer 21 to the lower layer 22, the lower layer compressed portion 24 is more in the same area of the topsheet 2 than the sheet compressed portion 23. It is preferable that the number and / or the total area is large, and it is more preferable that the ratio (the former / the latter) of the number of the sheet compression parts 23 and the number of the lower layer compression parts 24 is 1/4 to 1/50, Moreover, it is more preferable that the ratio (the former / the latter) of the total area of the sheet compression unit 23 and the total area of the lower layer compression unit 24 is 1/2 to 1/800.

In addition, from the viewpoint of texture, touch and liquid transferability, the number of sheet compression portions 23 per 100 mm ^{2 of the top} sheet is preferably 1 to 20, and the total area of the sheet compression portions 23 per area is 0.00. It is preferable that it is 1-35 mm < ² >. In addition, from the viewpoint of liquid migration, the number of the lower layer compression portions 24 per 100 mm ² of the surface sheet is preferably 4 to 35, and the total area of the lower layer compression portions 24 per same area is 5 to 80 mm ² . It is preferable.
The number, total area, and ratio thereof are measured per 100 mm ² , but the measurement area is a portion where the sheet compression portion 23 and the lower layer compression portion 24 are formed in a uniform pattern. In addition, when the compression portion formed in the fiber assembly for forming the lower layer overlaps with the sheet compression portion 23, the overlapping portion does not enter the number of lower layer compression portions 24 or the area when calculating the total area. .

In the topsheet 2, it is preferable that the fiber diameters of the constituent fibers are gradually or stepwise reduced from the skin side surface toward the absorber side surface from the viewpoint of improving the liquid migration property in the thickness direction.
As a specific form in which the fiber diameter of the constituent fibers is decreased in stages, the fiber diameter of the fibers constituting the lower layer 22 is smaller than the fiber diameter of the fibers constituting the upper layer 21, and the fiber diameters different for each layer A mode in which the average fiber diameter of the fibers constituting the lower layer 22 is smaller than the average fiber diameter of the fibers constituting the upper layer 21 by mixing these fibers can be exemplified.

  When fibers having different fiber diameters are mixed in one or both of the upper layer 21 and the lower layer 22, the average fiber diameter of the upper layer 21 or the lower layer 22 can be obtained from the weight ratio of the fibers constituting the upper layer or the lower layer. it can. For example, when the upper layer is composed of 75% by weight of fibers having a fiber diameter of 3 dtex and 25% by weight of fibers having 4 dtex, the average fiber diameter of the upper layer is 3.25 dtex (= 3 dtex × 0.75 + 4 dtex × 0.25).

  As a specific form in which the fiber diameter of the constituent fibers is gradually decreasing, the fiber aggregate constituting the upper layer 21 and / or the fiber aggregate constituting the lower layer 22 is directed from the skin side surface toward the absorber side. The form which has the gradient of the fiber diameter to which a fiber diameter becomes small can be mentioned.

  The fibers constituting the upper layer and the lower layer include pulp fibers, hydrophilic fibers such as rayon, cotton and cellulose acetate, polyolefin fibers such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, condensed fibers such as polyamide, and polyvinyl chloride. And fibers of vinyl monomer polymers such as polyvinyl acetate. These may be composed of a single component, or may be a side-by-side type or core-sheath type composite fiber consisting of a plurality of components. The hydrophobic synthetic fiber is preferably hydrophilized with a hydrophilic oil agent. In addition, it is preferable that the lower layer in the surface sheet of this embodiment does not contain heat-shrinkable fibers, particularly latent crimpable fibers, from the viewpoint of workability during high-speed production. The heat-shrinkable fiber is made of a thermoplastic polymer material and has heat-shrinkability, and the latent crimpable fiber can be handled in the same manner as a conventional non-woven fiber before being heated, and It is a fiber that has a property that a helical crimp is developed and contracted by heating at a predetermined temperature.

  From the viewpoint of making the sheet compression part 23 and / or the lower layer compression part 24 excellent in heat setting properties such as heat embossing and ultrasonic embossing, thereby improving the adhesion between the upper layer and the lower layer of the surface sheet, the upper layer and the lower layer Each has at least a part of its surface a heat-fusible fiber made of a thermoplastic fiber such as an olefin such as polyethylene or polypropylene (a composite fiber whose sheath component is made of a thermoplastic resin, a fiber made entirely of a thermoplastic resin, etc.) The content of the heat-fusible fiber is preferably 70 to 100% based on the weight of each of the upper layer and the lower layer.

  The topsheet of the present embodiment is formed by embossing the fiber assembly for forming the lower layer 22 to form the lower layer compression portion 24, and then laminating the fiber assembly for forming the upper layer 21 thereon, In the state, they are obtained by embossing them integrally.

  In addition, as a method of forming the sheet compression portion 23 and the lower layer compression portion 24, an adhesive or the like can be used instead of embossing.

  The fiber assembly for forming the lower layer 22 and the fiber assembly for forming the upper layer 21 are not limited, such as an air-through nonwoven fabric, a heat roll nonwoven fabric, a spunbond nonwoven fabric, and a spunlace nonwoven fabric. From the viewpoint of increasing the density of fibers in the vicinity of the compressed portion, an air-through nonwoven fabric is preferred.

  According to the surface sheet 2 of the present embodiment, a horizontal density gradient is formed in the sheet non-compressed portion 28 of the upper layer 21 so that the fiber density increases as the sheet compressed portion 23 is approached. As shown, the liquid A discharged (supplied) on the skin side surface of the top sheet 2 diffuses in the sheet non-compressed portion 28 of the upper layer 21 toward the sheet compressing portion 23 as shown by the arrow A1, and the sheet It moves smoothly from the vicinity of the compression part 23 to the absorber side through the lower layer 22. At the same time, as shown by the arrow A2, the liquid A has a coarse / dense gradient between the sheet uncompressed portion 28 and the lower layer uncompressed portion 29 even at a point where the liquid A does not diffuse (separate) much in the horizontal direction from the supplied portion. Due to the transition from the upper layer 21 to the lower layer 22 and the formation of the lower layer compression part 24, the boundary between the upper layer 21 and the lower layer 22 or the lower layer of the lower layer 22 due to the horizontal density gradient in the lower layer 22 The inside of the compression part 29 diffuses and smoothly moves from the vicinity of the lower layer compression part 24 in the lower layer 22 to the absorber side.

In this way, the liquid discharged (supplied) onto the top sheet 2 quickly moves to the absorber without remaining on the surface of the top sheet. Therefore, it is possible to effectively prevent discomfort and stuffiness due to the liquid remaining on the surface layer of the surface sheet, leakage due to the liquid flowing on the surface, etc., and further absorb liquids such as menstrual blood When it is used, the effect of concealing the color so as not to stand out is excellent.
In the surface sheet of the present invention, the basis weight of the two-layer structure portion 20 in which the upper layer 21 and the lower layer 22 are laminated is 20 to 70 g / m ² , particularly 30 to 60 g / m ² from the viewpoint of workability and texture. Preferably there is.

As mentioned above, although preferable embodiment of this invention was described, this invention can be changed suitably in the range which does not deviate from the meaning.
For example, the top sheet may have a single layer portion 25 composed of only the upper layer 21 at the front and rear end portions in the longitudinal direction, and the top sheet is formed on each of both side portions in the longitudinal direction of the sanitary napkin 1. You may arrange | position so that the longitudinal direction may correspond with the width direction of the sanitary napkin 1 so that the part 25 may be located. Further, the entire surface sheet may have a two-layer structure including the upper layer 21 and the lower layer 22. The sheet compression part 23 and the lower layer compression part 24 should just be formed in the at least excretion part of an absorbent article, and do not need to be formed in the whole surface sheet or the whole 2 layer structure part.

  Moreover, the surface sheet of the present invention may have a three-dimensional opening that penetrates the upper layer 21 and the lower layer 22, and a plurality of sheet compression portions 23 may be arranged on the inner wall surface of the three-dimensional opening. Such a surface sheet is, for example, the surface sheet 2 of the above-described embodiment between a pressing roll having a large number of perforated pins on the peripheral surface and a receiving roll having a large number of receiving holes into which the perforated pins are inserted. It is obtained by inserting and forming an opening in the top sheet 2.

  In addition to the sanitary napkin, the absorbent article of the present invention may be an incontinence pad, a panty liner, a disposable diaper, or the like.

FIG. 1 is a perspective view showing a surface sheet and a sanitary napkin using the surface sheet as an embodiment of the surface sheet of the absorbent article of the present invention. FIG. 2 is a schematic view showing a cross section taken along line II of FIG. FIG. 3 is a cross-sectional view showing details of a cross section in the thickness direction of the topsheet shown in FIG. FIG. 4A is a diagram illustrating a preferable example of the arrangement pattern of the sheet compression unit, and FIG. 4B is a diagram illustrating a preferable example of the arrangement pattern of the lower layer compression unit. FIG. 5 is a diagram for explaining the function of the top sheet of the present invention, and schematically showing a cross section in the thickness direction of the top sheet.

Explanation of symbols

1 Sanitary napkin (absorbent article)
2 Surface sheet 20 2 layer structure part 21 Upper layer 22 Lower layer 23 Sheet compression part 24 Lower layer compression part 25 Single layer part 3 Back surface sheet 4 Absorber

Claims (6)

It is composed of a laminated nonwoven fabric having an upper layer disposed on the skin side and a lower layer disposed on the absorber side, and is positioned between the sheet compression portions and a large number of sheet compression portions formed by integrally compressing the upper layer and the lower layer. And the lower layer compression part formed by compressing only the lower layer, and the minimum density of the part other than the sheet compression part and the lower layer compression part in the lower layer is other than the sheet compression part in the upper layer. A surface sheet of an absorbent article that is equal to or greater than the minimum density of the part. The top sheet of an absorbent article according to claim 1, wherein the lower layer compression section has a larger number and / or total area than the sheet compression section. The top sheet of an absorbent article according to claim 1 or 2, wherein an arrangement pitch of the lower layer compression parts is smaller than an arrangement pitch of the sheet compression parts. The said surface sheet is a surface sheet of the absorbent article in any one of Claims 1-3 in which the fiber diameter of a constituent fiber is reducing gradually or in steps toward the absorber side surface from the skin side surface. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent interposed between the two sheets,
The absorptive article which is the surface sheet according to claim 1 in which said surface sheet is. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent interposed between the two sheets, and has a substantially vertically long shape. And
The top sheet is made of a laminated nonwoven fabric having an upper layer disposed on the skin side and a lower layer disposed on the absorber side, and a plurality of sheet compression portions formed by integrally compressing the upper layer and the lower layer, and the sheet And a lower layer compression portion formed by compressing only the lower layer, and the top sheet is formed by extending the upper layer on both sides in the longitudinal direction of the absorbent article. Having a single layer portion
In the surface sheet, the portion having a two-layer structure in which the upper layer and the lower layer are laminated covers the absorber in the central region in the width direction of the absorbent article, and on both sides of the central region, An absorbent article in which the single layer portion covers the absorber.

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