JP6659338B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article.

  Because it has both soft touch and moderate strength, the surface sheet of the absorbent article uses a spunlace nonwoven fabric formed by using only hydrophilic fibers and entanglement of the hydrophilic fibers with a high-pressure water flow. It has been known. Spunlaced nonwoven fabrics formed from commonly used hydrophilic fibers are generally easy to fluff when worn for a long period of time, easily causing liquid residue on the topsheet, and giving the wearer a sense of discomfort. is there.

  The present applicant has proposed an absorbent article using a surface sheet mainly containing crimpable fibers, from the viewpoint that twisting is unlikely to occur even when worn for a long time, and it is difficult for the wearer to feel uncomfortable. 1).

  Further, as an absorbent article using a surface sheet mainly containing crimpable fibers, Patent Document 2 discloses that an absorbent article is formed by developing a crimp of a latent crimpable fiber after sheet processing by a high-pressure water flow. An absorbent article using a nonwoven fabric for a topsheet is disclosed. Patent Document 3 discloses a nonwoven fabric in which, as a topsheet for an absorbent article, a fiber layer mainly containing highly shrinkable fibers is integrated by entanglement of the fibers, and the highly shrinkable fibers are shrunk by heat treatment. Is disclosed.

JP 2007-097945 A JP 2012-75553 A JP-A-7-3598

  However, Patent Literature 1 does not describe anything about including a hydrophilic fiber in addition to the crimpable fiber. In addition, as described above, the topsheet for an absorbent article described in Patent Literature 1 is unlikely to cause swelling even when worn for a long time, but is intended to achieve a soft and soft touch. There was a request.

  Further, Patent Document 2 and Patent Document 3 do not disclose a surface sheet in which a hydrophilic fiber is used as a main constituent fiber and a crimpable fiber is contained in the constituent fiber.

  Therefore, an object of the present invention is to provide an absorbent article that can solve the above-mentioned disadvantages of the related art.

  The present invention is an absorbent article comprising a liquid-permeable top sheet forming a skin-facing surface, having a longitudinal direction corresponding to the front-back direction of the wearer and a width direction orthogonal to the longitudinal direction, wherein the top sheet is Comprises a non-heat-fusible hydrophilic fiber and a heat-fusible helical crimped fiber, wherein the hydrophilic fiber has a blending ratio of 50% by mass or more with respect to the whole fibers constituting the topsheet, The sheet provides an absorbent article in which the spirally crimped fibers are fused together or the spirally crimped fibers are fused to the hydrophilic fibers.

  ADVANTAGE OF THE INVENTION According to this invention, soft and soft touch is obtained, it is hard to fluff by wearing for a long time, it is hard to generate a liquid residue on a surface sheet, and it is hard to give a wearer a sense of incongruity.

FIG. 1 is a perspective view showing a panty liner according to one embodiment of the present invention. FIG. 2 is an enlarged sectional view taken along line II-II of FIG. FIG. 3 is a partially cutaway perspective view showing an enlarged main part of the panty liner shown in FIG. 1 on the skin facing surface side. FIG. 4 is an enlarged sectional view of a main part of the topsheet provided in the panty liner shown in FIG. 1. FIG. 5 is a schematic view showing a manufacturing apparatus suitably used for manufacturing a topsheet provided in the panty liner shown in FIG. FIG. 6 is a sectional view taken along line VI-VI shown in FIG.

Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings.
FIG. 1 is a perspective view of a panty liner 1 (hereinafter, simply referred to as “panty liner 1”) according to an embodiment of the present invention. FIG. 2 is an enlarged sectional view taken along line II-II of FIG.

  As shown in FIGS. 1 and 2, the panty liner 1 includes a liquid-permeable top sheet 2 that forms a skin-facing surface. The panty liner 1 has a vertically long shape, and has a vertical direction corresponding to the front-rear direction of the wearer and a width direction orthogonal to the vertical direction. In FIG. 1, the vertical direction and the width direction are shown as an X direction and a Y direction, respectively. The vertical direction X corresponds to the front-back direction of the wearer when the panty liner 1 is worn, and the width direction Y is a direction orthogonal to the vertical direction X in a plan view of the panty liner 1. Further, the thickness direction of the panty liner 1 will be described as a Z direction.

  As shown in FIGS. 1 and 2, the panty liner 1 includes a top sheet 2, a liquid-impermeable back sheet 3, and an absorber 4 interposed between these two sheets 2, 3. The lower sheet 5 is provided on the non-skin facing surface side of the top sheet 2. Preferably, in the panty liner 1, the lower layer side sheet 5 is disposed between the topsheet 2 and the absorber 4 in a region where the absorber 4 exists. The panty liner 1 has an oval shape in plan view in which the central portion in the vertical direction X is constricted. Here, the liquid impermeability of the back sheet 3 includes liquid impermeability.

  As shown in FIGS. 1 and 2, in the panty liner 1, a rectangular absorber 4 long in the same direction as the front-rear direction when worn, and the lower sheet 5 covering the entire skin-facing surface of the absorber 4 It has. As shown in FIGS. 1 and 2, the topsheet 2 covers the entire skin-facing surface of the lower sheet 5. The top sheet 2 and the lower sheet 5 have portions extending outward from both ends and both sides in the longitudinal direction X of the absorber 4. The back sheet 3 covers the entire non-skin-facing surface of the absorber 4 and has portions extending outward from both ends and both sides in the longitudinal direction X of the absorber 4. The top sheet 2, the lower layer sheet 5, and the back sheet 3 have portions extending outward from both ends and both sides in the longitudinal direction X of the absorber 4 at the peripheral portion 7 of the panty liner 1 by fusion (heat embossing). , Ultrasonic embossing, high-frequency embossing) or an adhesive. As described above, the rectangular absorber 4 is sandwiched between the lower layer side sheet 5 and the back sheet 3. The non-skin-facing surface of the back sheet 3 of the panty liner 1 is provided with an adhesive portion (not shown) for fixing to underwear such as shorts.

  The topsheet 2 includes non-heat-fusible hydrophilic fibers 2f1 and heat-fusible helical crimped fibers 2f2 (see FIG. 4). The “non-heat-fusible” fibers forming the topsheet 2 mean fibers that do not melt even when heated and do not fuse with each other. Further, the “heat-fusible” fiber means a fiber that can be melted by heating and fused to other heat-fusible fibers or other fibers (including the non-heat-fusible fibers). Further, the “hydrophilic fiber” is a fiber that can retain moisture, and does not include a fiber obtained by treating the surface of a hydrophobic fiber with a hydrophilic agent. The blending ratio of the non-heat-fusible hydrophilic fibers 2f1 to the entire fibers constituting the topsheet 2 is 50% by mass or more. The blending ratio of the non-heat-fusible hydrophilic fiber 2f1 to the entire fiber constituting the topsheet 2 is 50% by mass or more from the viewpoint of the touch and the ability to absorb a bodily fluid such as a small amount of vagina or sweat. It is more preferably at least 100% by mass, more preferably less than 100% by mass, even more preferably at most 90% by mass.

  As the non-heat-fusible hydrophilic fibers 2f1, natural fibers, regenerated cellulose fibers, semi-synthetic fibers, or the like can be used. Examples of the natural fiber include cotton fiber, silk fiber, and lyocell fiber which is a purified cellulose fiber. Examples of the regenerated cellulose fiber include regenerated fibers such as rayon fiber and cupra fiber, and examples of the semi-synthetic fiber include acetate. It is preferable to use natural fibers, such as cotton fibers and lyocell fibers, as the non-heat-fusible hydrophilic fibers 2f1 from the viewpoint of feel and texture.

  The crimped fibers constituting the topsheet 2 include helical crimped fibers 2f2. In the panty liner 1 of the present embodiment, the helical crimped fiber is a latently crimpable fiber that has developed a helical crimp by heat treatment at the shrinkage temperature of the fiber. Latent crimpable fibers are fibers that can be handled in the same manner as conventional nonwoven fabric fibers before they are heated, and have the property of developing helical crimps and shrinking by heating at shrinkage temperatures. It is.

  The latently crimpable fiber is composed of, for example, an eccentric core-sheath type composite fiber or a side-by-side type composite fiber containing two types of thermoplastic polymer materials having different shrinkages. Examples thereof include those described in JP-A-9-296325 and Japanese Patent No. 2759331. Examples of two types of thermoplastic polymer materials having different shrinkage rates include, for example, a combination of an ethylene-propylene random copolymer and polypropylene.

  The shrinkage temperature is a component having a relatively low softening point and a component having a relatively high softening point. Means temperature. Further, the shrinkage start temperature means a softening point of a component having a relatively low softening point. When the latently crimpable fiber is heated to a temperature between both softening points, only the component having a low softening point starts to shrink. As a result, the entire fiber contracts helically and crimps are developed, forming helically crimped fibers. The temperature of the heat treatment can be appropriately adjusted according to the softening point of the resin constituting the latently crimpable fiber, in other words, according to the shrinkage temperature. That is, "spiral crimped fiber" refers to a crimped fiber that exhibits a spiral crimp while leaving room for crimping, and a spiral crimp without leaving a room for crimping. And crimped fibers. The term "crimped fiber" means both the "spiral-shaped crimped fiber" and the latently-crimpable fiber.

  The helical crimped fiber 2f2 preferably has a blending ratio of 10% by mass or more, more preferably 20% by mass or more, and 50% by mass or less with respect to the entire fiber constituting the topsheet 2. It is more preferably 40% by mass or less, more preferably 10% by mass or more and 50% by mass or less, and further preferably 20% by mass or more and 40% by mass or less.

  The topsheet 2 may include, for example, other fibers in addition to the non-heat-fusible hydrophilic fibers 2f1 and the helical crimped fibers 2f2. It is composed of only two types of fibers, fiber 2f1 and spiral crimped fiber 2f2. The blending ratio of other fibers with respect to the entire fibers constituting the topsheet 2 is preferably 40% by mass or less, more preferably 20% by mass or less, and the lower limit is 0% by mass from the viewpoint of texture and absorptivity. %. Examples of the other fibers include heat-fusible synthetic fibers such as core-sheath type polyethylene-polypropylene composite fiber, core-sheath type polyethylene-polyethylene terephthalate composite fiber, and polyethylene terephthalate single fiber.

  In the topsheet 2, the helical crimped fibers 2f2 and 2f2 or the helical crimped fibers 2f2 are fused to the hydrophilic fibers 2f1. This is because (1) when at least a part of the helical crimped fibers 2f2 and 2f2 are fused, (2) at least a part of the helical crimped fiber 2f2 becomes the hydrophilic fiber 2f1. This includes the case where they are formed by fusion bonding, and the case where (1) and (2) are mixed. Preferably, the topsheet 2 is formed by fusing at least a part of the spiral crimped fibers 2f2 and 2f2 and fusing at least a part of the spiral crimped fiber 2f2 to the hydrophilic fiber 2f1. I have.

  The topsheet 2 can be manufactured by a spunlace method (water entanglement method) in which fibers are entangled with each other by a high-pressure water flow, an air-through method, or the like. However, the viewpoint that the non-heat-fusible hydrophilic fibers 2f1 contain 50% by mass or more. For this reason, it is preferable to manufacture by a spunlace method. For example, in the case of manufacturing by the spunlace method, the hydrophilic fiber 2f1 and the latently crimpable fiber 2f2 ′ before being formed into the helical crimped fiber 2f2 (before the helical crimp is developed) are mixed and carded. After producing a card web, high-pressure water is sprayed on the card web to obtain a web in which fibers are entangled. Then, the web in which the fibers are entangled is placed in a thermostatic dryer, and heat treatment is performed to cause the latently crimpable fiber 2f2 'to develop a spiral crimp. At the same time, in the same step, at least a part of the helical crimped fibers 2f2 and 2f2 are fused together, and a part of the helical crimped fiber 2f2 is fused to the hydrophilic fiber 2f1. 2 can be manufactured. The card web produced by the card method is a fiber aggregate in a state before being made into a nonwoven fabric.

The nonwoven fabric forming the topsheet 2 of the panty liner 1 will be described in more detail.
FIG. 3 is a perspective view of the panty liner 1 of the present embodiment in a state in which the topsheet 2 is in contact with the lower sheet 5 as the lower member. FIG. 4 is a schematic diagram showing a cross section in the thickness direction of the topsheet 2 shown in FIG.

  In the panty liner 1, as shown in FIGS. 1 and 2, the topsheet 2 has a concavo-convex structure in which streaky ridges 21 and concave ridges 22 extending in the vertical direction X are alternately arranged in the width direction Y. Is formed. Preferably, as shown in FIGS. 3 and 4, the topsheet 2 is adjacent to a plurality of ridges 21 each having a front surface u and a back surface d each having a cross-sectional shape protruding upward in the thickness direction. A concave ridge portion 22 is provided between the corresponding convex ridge portions 21 and 21. The cross section shape of the front and back surfaces u and d is concave toward the upper side in the thickness direction of the nonwoven fabric. In other words, the concave streak portion 22 has a cross-sectional shape of both the front and back surfaces u and d that is convex toward the lower side in the thickness direction (Z direction) of the nonwoven fabric. The plurality of ridges 21 each extend continuously in the vertical direction X of the panty liner 1, and the plurality of recesses 22 also extend in a groove shape that continuously extends in the vertical direction X of the panty liner 1. No. The ridges 21 and the valleys 22 are parallel to each other and are alternately arranged in the width direction Y.

  As shown in FIG. 4, the topsheet 2 is located at the top region 23a of the convex streak portion 21, the bottom region 23b of the concave streak portion 22, and between them, when the topsheet 2 is viewed in cross section along the thickness direction as shown in FIG. And an intermediate portion 23c. The top region 23a, the bottom region 23b, and the middle region 23c extend continuously in the vertical direction X of the panty liner 1. The top region 23a of the protruding ridge portion 21, the bottom region 23b of the concave ridge portion 22, and the intermediate region 23c divide the thickness of the top sheet 2 in the Z direction into three when the cross section of the top sheet 2 is taken along the thickness direction. Then, the upper part in the thickness direction is distinguished as a top area 23a, the central part is identified as an intermediate area 23c, and the lower part is identified as a bottom area 23b.

  As shown in FIG. 4, when the topsheet 2 is observed along its thickness direction, the fiber density in the intermediate region 23c is lower than the fiber density in the top region 23a and the fiber density in the bottom region 23b. In addition, since the topsheet 2 is formed of a nonwoven fabric containing 50% by mass or more of the non-heat-fusible hydrophilic fibers 2f1, in the panty liner 1, in the panty liner 1, the top region 23 a is formed for a reason described in a manufacturing method described later. The fineness of the hydrophilic fiber 2f1, the fineness of the hydrophilic fiber 2f1 in the bottom region 23b, and the fineness of the hydrophilic fiber 2f1 in the intermediate region 23c are formed to the same fineness.

Fiber density in the top zone _{23a (D} 23a), and the ratio of the fiber density of the intermediate portion region 23c _{(D 23c)} against the fiber density _{(D 23b)} at the bottom area _{23b (D 23c / D 23a,} D 23c / D 23b ) Is preferably from 0.3 to 0.95, more preferably from 0.4 to 0.7.
It respect to specific values of the fiber density of the surface sheet 2, the fiber density of the intermediate portion region 23c _{(D 23c),} it is preferable, 0.1 g / cm ³ or more and 0.005 g / cm ³ or more but more preferably, and is preferably at 0.1 g / cm ³ or less, preferably specifically at most 0.005 g / cm ³ or more ^{0.1g / cm 3, 0.01g / cm} 3 or more More preferably, it is 0.1 g / cm ³ or less.
The fiber density in the fiber density _{(D 23a),} and a bottom zone 23b at the top region 23a _{(D 23b),} it is preferably, 0.1 g / cm ³ or more that is 0.05 g / cm ³ or more More preferably, it is preferably 0.5 g / cm ³ or less, more preferably 0.2 g / cm ³ or less, and specifically 0.005 g / cm ³ or more and 0.2 g / cm ^{3. 3} or less, more preferably 0.1 g / cm ³ or more and 0.2 g / cm ³ or less.
Fiber density of the entire surface sheet 2 is preferably 0.01 g / cm ³ or more, further preferably 0.05 g / cm ³ or more, and is preferably at 0.05 g / cm ³ or less , 0.2 g / cm ³ or less, more preferably 0.01 g / cm ³ or more and 0.5 g / cm ³ or less, and more preferably 0.05 g / cm ³ or more and 0.2 g / cm ³ or less. More preferably, it is not more than cm ³ .
The fiber density of each part is determined by the following measurement method.

The basis weight of the intermediate region 23c is preferably 5 g / m ² or more, more preferably 10 g / m ² or more, and preferably 30 g / m ² or less, and 25 g / m ² or less. Is more preferably 5 g / m ² or more and 30 g / m ² or less, more preferably 10 g / m ² or more and 25 g / m ² or less.
Further, the basis weight in the top region 23a and the basis weight in the bottom region 23b are preferably 10 g / m ² or more, more preferably 20 g / m ² or more, and 40 g / m ² or less. Is preferably 35 g / m ² or less, more preferably 10 g / m ² or more and 40 g / m ² or less, and more preferably 20 g / m ² or more and 35 g / m ² or less. Is more preferred.
The basis weight of the entire topsheet 2 is preferably 5 g / m ² or more, more preferably 10 g / m ² or more, and preferably 40 g / m ² or less, and 30 g / m ² or less. Is more preferably 5 g / m ² or more and 40 g / m ² or less, more preferably 10 g / m ² or more and 30 g / m ² or less.
The grammage of each part is determined by the following measuring method.

<Method of measuring the grammage of the intermediate area 23c>
From the panty liner 1 in a state where no load is applied, a cut sample is cut out by cutting into a rectangular shape having a predetermined length A in the vertical direction X and a predetermined length B in the width direction Y without peeling the topsheet 2. Next, in the cut sample, the cut cross section in the width direction Y is observed, and at a position where the thickness of the top sheet 2 in the Z direction is divided into three equal parts, the width C (the length in the Y direction) of the top region 23a or the bottom portion is determined. The width C ′ (length in the Y direction) of the region 23b is measured, and the total value F of the width C and the width C ′ in the width B of the sample is obtained. Next, only the topsheet 2 is peeled off from the cut sample so that the uneven structure is not crushed, and the weight (W) of the peeled topsheet 2 is measured. From the above results, the actual basis weight (E) of the topsheet 2 is determined by the following equation (1).
Actual basis weight of top sheet E = W / (A × B) (1)

Next, the peeled top sheet 2 is stretched in the width direction (Y direction) until there is no uneven structure, and the length (G) of the stretched width direction (Y direction) is measured. Then, the total width (H) of the intermediate region 23c is calculated by the following equation (2).
Total width (H) of middle section 23c = G−F (2)

Further, the basis weight (I) of the topsheet 2 after being stretched in the width direction (Y direction) is calculated by the following equation (3). The calculated basis weight (I) is the basis weight of the entire topsheet 2.
Basis weight (I) of topsheet 2 after stretching = W / (A × G) (3)

Then, the grammage (J) of the intermediate region 23c is determined by the following equation (4).

Basis weight of intermediate section 23c (J)
= ((W−I) × A × F) / (A × H) (4)

<Method of Measuring Fiber Density of Intermediate Region 23c>
Regarding the fiber density (D _23c ) of the intermediate region 23 c, in the cut sample cut out above, the cut section in the width direction (Y direction) was observed, and the thickness of the surface sheet 2 in the Z direction was divided into three equal regions. Is measured using an image analyzer. The measurement is performed in a state where no load is applied. For example, a digital microscope (model number VHX-1000) manufactured by KEYENCE CORPORATION can be used as the image analyzer. Then, the fiber density (K) of the intermediate region 23c is determined by the following equation (5).
Fiber density (D _23c ) of middle region 23c = J / K (5)

<Method of measuring basis weight in top region 23a and basis weight in bottom region 23b>
Further, the basis weight (L) in the top region 23a and the basis weight (L) in the bottom region 23b are obtained by the following equation (6).
Basis weight (L) at top area 23a (bottom area 23b)
= (W / (A × F)) / 2 (6)

<Method of measuring fiber density in top region 23a and fiber density in bottom region 23b>
Regarding the fiber density (D _23a , D _23b ) of the top region 23a (bottom region 23b), in the cut sample obtained above, the cut cross section in the width direction (Y direction) was observed, and the Z direction of the surface sheet 2 was observed. The thickness (M) of the top region 23a of the protruding ridge 21 or the bottom region 23b of the concave ridge 22 obtained by dividing the thickness into three is measured using an image analyzer. The measurement is performed in a state where no load is applied. As the image analyzer, for example, a scanning electron microscope (model number JCM-5100) manufactured by JEOL Ltd. can be used. Then, the fiber density (D _23a , D _23b ) in the top region 23a (bottom region _23b ) is determined by the following equation (7).
Fiber density (D _23a , D _23b ) in top region 23a (bottom region _23b )
= L / M (7)

  Further, regarding the fiber density of the entire topsheet 2, the cut cross section in the width direction of the cut sample cut out above was observed, and the thickness of the topsheet 2 was randomly measured using the image analysis device. N) is calculated. Then, the basis weight (I) of the entire topsheet 2 obtained by the above equation (3) is divided by the average thickness (N) to obtain the fiber density of the whole topsheet 2.

  When the topsheet 2 is viewed in a plan view, the pitch between the tops of the ridges 21 adjacent in the width direction Y is preferably 0.5 mm or more and 5 mm or less, more preferably 1 mm or more and 3 mm or less. The height h (see FIG. 3) of the ridge 21 is preferably 0.5 mm or more and 5 mm or less, more preferably 1 mm or more and 2 mm or less. The height h is measured under no load by observing a cross section in the thickness direction of the topsheet 2 with a microscope.

  Further, in the panty liner 1, the top sheet 2 comes into contact with the lower sheet 5 disposed on the non-skin facing surface side at the bottom region 23b of the concave streak portion 22, as shown in FIGS. I have. And in the panty liner 1, the lower layer side sheet 5 contains the heat-fusible fiber. As the lower sheet 5 containing the heat-fusible fibers, nonwoven fabrics obtained by various manufacturing methods can be used. For example, an air-through nonwoven fabric obtained by forming a heat-fusion point between fibers by an air-through method on a fiber web of a heat-fusible fiber obtained by a card method or an air laid method, and a heat-bondable fiber web obtained by a card method is heated. Various nonwoven fabrics, such as a heat roll nonwoven fabric, a heat embossed nonwoven fabric, a spunlace nonwoven fabric, a needle punched nonwoven fabric, a resin bonded nonwoven fabric, and the like, in which a heat fusion point between fibers is formed by a roll method, can be used.

  In the panty liner 1, the spirally crimped fibers 2 f 2 of the topsheet 2 and the heat-fusible fibers of the lower layer side sheet 5 are fused to form a fusion point with each other. The topsheet 2 is fixed on the skin-facing surface of the lower sheet 5 via the recess 6 at the bottom region 23b of the recess 22. The concave portion 6 is formed, for example, by performing a heat embossing process. In the concave portion 6, the helical crimped fiber 2f2 of the top sheet 2 and the heat-fusible fiber of the lower layer side sheet 5 are fused. In addition, the fiber density is relatively high as compared with the peripheral portion of the concave portion 6. In the panty liner 1, the concave portions 6 are intermittently arranged in the vertical direction X at the bottom region 23 b of each concave streak portion 22.

  In the panty liner 1, the absorber 4 is made of an absorbent sheet. Specifically, the absorbent body 4 of the panty liner 1 can be used by cutting one absorbent sheet into a predetermined shape, and can be used as a multilayer sheet by bonding a plurality of absorbent sheets. A multilayer sheet formed by folding one absorbent sheet can also be used as the absorbent sheet. In addition, the absorbent article of the present invention is usually used for absorbent articles such as sanitary napkins, and has an absorbent core composed of absorbent polymer particles and a fiber material and covered with tissue paper. It can also be used.

  As the absorbent sheet, by bonding between the constituent fibers or between the constituent fibers and the water-absorbing polymer via the adhesive force generated in the water-absorbing polymer in a wet state or a binder such as an adhesive or an adhesive fiber added separately. A sheet shape or the like can be preferably used. Further, as an absorbent sheet, an absorbent sheet manufactured by the method described in JP-A-8-246395, a pulverized pulp and a water-absorbing polymer supplied in an air stream are deposited, and then an adhesive (eg, vinyl acetate) is deposited. Sheet, hardened with PVA, etc.), absorbent sheet obtained by applying hot-melt adhesive between paper and non-woven fabric and then spraying super-absorbent polymer, pulp air-laid non-woven fabric, spun bond An absorbent sheet or the like obtained by blending a superabsorbent polymer during the manufacturing process of the nonwoven fabric or the meltblown nonwoven fabric can also be used. In particular, from the viewpoint of absorbability such as liquid return to the surface of the panty liner 1, an absorbent sheet obtained by blending a superabsorbent polymer during an air-laid nonwoven fabric manufacturing process containing pulp fibers as a main component is preferably used. .

The thickness of the absorber 4 is preferably from 0.1 mm to 1.0 mm, more preferably from 0.2 mm to 0.8 mm. The thickness of the absorber 4 is measured by the following method.
The thickness T is measured using a Peacock-type precision measuring instrument (model R1-C) which is a micrometer having two parallel pressing surfaces (fixed pressing surface and movable pressing surface). The measurement is performed at a diameter of the measuring element movable pressing surface of 5 mm and a pressure of 100 kPa or less. The size of the test piece for measurement shall be equal to or larger than the size of the following plate. A 20 mm × 20 mm plate (mass: 5.4 g) is placed on the test piece, the measuring element movable pressure surface is operated at a speed of 2 mm / s, the plate is applied to the plate, and the value immediately after stabilization is read. The pressure between the pressurized surfaces (the pressure applied to the test piece) is 1.3 kPa or less.

  As the material for forming the back sheet 3 of the panty liner 1, various materials conventionally used for the back sheet of the absorbent article can be used without any particular limitation. For example, a liquid-impermeable or water-repellent resin film For example, a laminated sheet of a resin film and a nonwoven fabric can be used.

  In the panty liner 1 of the present embodiment, the nonwoven fabric having a concavo-convex structure used as the surface sheet 2 is manufactured as a nonwoven fabric including a stretching step of unidirectionally stretching a nonwoven fabric containing 50% by mass or more of the non-heat-fusible hydrophilic fibers 2f1. It is suitably manufactured by the method. An embodiment of a method for manufacturing the surface sheet 2 having the uneven structure will be described with reference to FIG. FIG. 5 schematically shows a preferable manufacturing apparatus 100 used in the method of manufacturing the topsheet 2 having the uneven structure. The manufacturing apparatus 100 includes a stretching unit 8.

  As shown in FIG. 5, the extending portion 8 includes a pair of concave and convex rolls 81 and 82 which can be engaged with each other. The pair of concave and convex rolls 81 and 82 are formed so as to be heatable, and are formed by alternately disposing large-diameter convex portions 83 and 84 and small-diameter spacers 85 and 86 in the roll axis direction. Although the concavo-convex rolls 81 and 82 are formed to be heatable, they may or may not be heated.

  6, in the manufacturing apparatus 100, as shown in FIG. 6, the interval (pitch) between the large-diameter convex portions 83, 83 adjacent to each other in the roll axis direction of one of the concavo-convex rolls 81, and the roll axis of the other concavo-convex roll 82. The intervals (pitch) between the large-diameter convex portions 84, 84 adjacent to each other in the direction are the same interval (pitch) w, and the interval (pitch) w is preferably 0 in terms of texture, cushioning, and absorptivity. It is not less than 0.5 mm and not more than 5 mm, particularly preferably not less than 1 mm and not more than 3 mm. From the same viewpoint, as shown in FIG. 6, the pushing amount t of the pair of concave and convex rolls 81 and 82 (the distance between the apex of the large-diameter convex portion 83 and the apex of the large-diameter convex portion 84 adjacent to each other in the roll axis direction) is , Preferably 0.5 mm or more and 5 mm or less, particularly preferably 1 mm or more and 2 mm or less. From the same viewpoint, the mechanical stretching ratio is preferably larger than 1 and 5 or less, particularly preferably 2 or more and 4 or less.

A method of manufacturing the surface sheet 2 having the uneven structure using the manufacturing apparatus 100 having the above configuration will be described.
First, as shown in FIG. 5, a raw nonwoven fabric 2a (a flat surface sheet 2 having no uneven structure) containing 50% by mass or more of the non-heat-fusible hydrophilic fibers 2f1 and the helical crimped fibers 2f2 is prepared. prepare. Then, the longitudinal direction X of the raw nonwoven fabric 2a is made to coincide with the machine direction (MD, flow direction) when manufacturing the topsheet 2 having the uneven structure using the manufacturing apparatus 100. In other words, the width direction Y of the raw nonwoven fabric 2a is made to coincide with the orthogonal direction (CD, roll axis direction) orthogonal to the machine direction (MD, flow direction). Next, as shown in FIG. 5, the raw nonwoven fabric 2a is transported between a pair of concave and convex rolls 81 and 82, and as shown in FIG. 6, the raw nonwoven fabric 2a is stretched in the width direction (Y direction). Here, the raw nonwoven fabric 2a is formed to contain the non-heat-fusible hydrophilic fibers 2f1 in an amount of 50% by mass or more, and there is little fusion-bonded helical crimped fibers 2f2 and 2f2. The hydrophilic fiber 2f1 and the helical crimped fiber 2f2 constituting the raw nonwoven fabric 2a in the portion stretched between the top of the large-diameter convex portion 83 of the roll 81 and the top of the large-diameter convex portion 84 of the other uneven roll 82. The arrangement is shifted. The portion where the constituent fibers of the raw nonwoven fabric 2a are displaced in this manner becomes the intermediate region 23c of the topsheet 2 having the uneven structure. Further, at the position of the top of the large-diameter convex portion 83 of one of the concave-convex rolls 81, the unstretched portion becomes the bottom region 23b of the concave stripe portion 22 of the topsheet 2 having the concave-convex structure. At the position of the top of the large-diameter convex portion 84 of the other concave-convex roll 82, the portion that is not stretched becomes the top region 23a of the convex ridge 21 of the topsheet 2 having the concave-convex structure.

  Accordingly, in the manufactured topsheet having an uneven structure, the fiber density in the intermediate region 23c is lower than the fiber density in the top region 23a of the ridge 21 and the fiber density in the bottom region 23b of the concave ridge 22. I have. Further, as described above, since the raw nonwoven fabric 2a is formed so as to contain the non-heat-fusible hydrophilic fiber 2f1 by 50% or more, the top of the large-diameter convex portion 83 of the one uneven roll 81 and the other uneven roll are used. In the portion that is stretched between the top of the large-diameter convex portion 84 and the top of the large-diameter convex portion 84, the fiber diameter of the hydrophilic fiber 2f1 constituting the raw nonwoven fabric 2a is unlikely to be thin, and the arrangement of the hydrophilic fiber 2f1 and the spiral crimped fiber 2f2 is shifted. It is easy to become only. Therefore, the fineness of the hydrophilic fiber 2f1 in the top region 23a, the fineness of the hydrophilic fiber 2f1 in the bottom region 23b, and the fineness of the hydrophilic fiber 2f1 in the intermediate region 23c are the same. In order to further ensure this effect, the content of the helical crimped fiber 2f2 as the raw nonwoven fabric 2a is preferably from 10% by mass to 50% by mass, more preferably from 20% by mass to 40% by mass. It is even more preferred. Similarly, as the raw material nonwoven fabric 2a, the content of the hydrophilic fiber 2f1 of the non-heat-fusible fiber is preferably 50% by mass or more and less than 100% by mass, and 60% by mass or more and 90% by mass or less. Is more preferred.

  The topsheet 2 having the concavo-convex structure manufactured as described above is conveyed downstream by a pair of concavo-convex rolls 81 and 82 while being deformed into a concavo-convex shape. Then, the surface sheet 2 having the concavo-convex structure is arranged on the lower layer side sheet 5, intermittently heat-embossed at a position corresponding to the bottom region 23 b of the concave streak portion 22, and 2 and the lower sheet 5 are fixed. Thereafter, the panty liner 1 is introduced into a production line, and the panty liner 1 is manufactured.

  In the panty liner 1 manufactured as described above, as shown in FIG. 4, the topsheet 2 has at least two types of non-heat-fusible hydrophilic fibers 2f1 and heat-fusible helical crimped fibers 2f2. Contains fibers. The non-heat-fusible hydrophilic fiber 2f1 has a compounding ratio of 50% by mass or more with respect to the whole fiber constituting the topsheet 2, and includes the spirally-crimped fiber 2f2, so that it has a soft and soft touch. Is obtained. In addition, since helical crimped fibers are contained, liquid residue hardly occurs on the topsheet 2. Further, since the topsheet 2 is formed by fusing the spirally crimped fibers 2f2 and 2f2 together and / or the hydrophilic fiber and the spirally crimped fiber, the topsheet 2 does not easily fluff even when worn for a long time, Is less likely to give a sense of discomfort. In particular, if the topsheet 2 is formed of only two types of fibers, that is, the non-heat-fusible hydrophilic fibers 2f1 and the helical crimped fibers 2f2, the above-described effect can be further achieved.

  Further, in the panty liner 1, as shown in FIG. 2, the spirally crimped fibers 2 f 2 of the top sheet 2 and the heat-fused fibers of the lower layer side sheet 5 are fused. Specifically, the topsheet 2 is fixed on the skin-facing surface of the lower layer side sheet 5 via the concave portion 6 at the bottom region 23 b of the concave streak portion 22. Therefore, even if worn for a long time, it is harder to fluff and it is harder to give the wearer an uncomfortable feeling.

  Further, in the panty liner 1, as shown in FIG. 2, a surface sheet 2 having an uneven structure is used as the surface sheet. As shown in FIG. 4, when the surface sheet 2 having a concavo-convex structure is viewed in cross section along the thickness direction as shown in FIG. 4, the fiber density of the intermediate region 23 c is higher than the fiber density of the top region 23 a and the fiber density of the bottom region 23 b. It is lower than the fiber density. Since the intermediate region 23c has such a low fiber density, it is easy to absorb body fluid such as menstrual blood from the intermediate region 23c. Since such an intermediate region 23c extends in the vertical direction X and is intermittently arranged in the width direction Y, it is difficult for the body fluid to spread in the width direction Y of the panty liner 1 and the diffusion area of the body fluid can be suppressed. The unpleasant stickiness is suppressed. The bodily fluid absorbed from the intermediate region 23c easily moves to the bottom region 23b of the concave portion 22 having a high fiber density due to gravity and a density gradient, and the bodily fluid transferred to the bottom region 23b contacts the bottom region 23b. It is easy to transfer to the absorber 4 via the lower layer side sheet 5 which is formed.

  Further, since the top region 23a of the high density ridge portion 21 and the bottom region 23b of the concave ridge portion 22 each extend in the vertical direction X, the body fluid is unlikely to spread in the width direction Y of the panty liner 1, and Lateral leakage can be prevented. Further, the top region 23a of the high density ridge portion 21 and the bottom region 23b of the low ridge portion 22 extend in the vertical direction X, respectively. Since the topsheet 2 is fixed to the sheet 5, the uneven structure of the topsheet 2 is unlikely to be crushed, and the above effect can be maintained.

  The lower layer sheet 5 preferably has the following configuration from the viewpoint of more surely exhibiting the above-described effects.

Lower side sheet 5, from the viewpoint of cushioning properties and twist suppression improvement, the basis weight (BW ₅₎ is higher than the basis weight of the topsheet 2 basis weight of (BW ₂₎ and the absorber 4 (BW ₄₎ Is preferred. Here, the basis weight of the topsheet 2 means the basis weight (I) of the entire topsheet 2 obtained by the above equation (4). The basis weight of the topsheet 2 basis weight of (BW ₂₎ and the absorber 4 basis weight of the lower layer side sheet 5 against (BW ₄₎ the ratio of _{(BW 5) (BW 5 /} BW 2, BW 5 / BW 4) is It is preferably from 1.01 to 2.0, more preferably from 1.05 to 2.0.

The basis weight (BW ₅ ) of the lower layer side sheet 5 is preferably 10 g / m ² or more, more preferably 30 g / m ² or more, and preferably 60 g / m ² or less, and 50 g / m ² or less. more preferably / ^{m 2} or less, preferably specifically at 60 g / ^{m 2} or less 10 g / ^{m 2} or more, more preferably 30 g / ^{m 2} or more 50 g / ^{m 2} or less.

The basis weight (BW ₄ ) of the absorber 4 is preferably 10 g / m ² or more, more preferably 20 g / m ² or more, and preferably 80 g / m ² or less, and 40 g / m ² or less. still more preferably m ² or less, and further preferably in particular it is 10 g / ^{m 2} or more 80 g / ^{m 2} or less and preferably, 20 g / ^{m 2} or more 40 g / ^{m 2} or less.

The density (D ₅ ) of the lower layer side sheet 5 is preferably 0.02 g / cm ³ or more, more preferably 0.04 g / cm ³ or more, and is 0.4 g / cm ³ or less. Is preferably 0.2 g / cm ³ or less, more preferably 0.02 g / cm ³ or more and 0.4 g / cm ³ or less, and more preferably 0.04 g / cm ³ or more and 0 or less. More preferably, it is not more than 0.2 g / cm ³ .

The density of the absorbent body 4 _{(D 4)} is preferably at 0.01 g / cm ³ or more, further preferably 0.05 g / cm ³ or more, and is 0.5 g / cm ³ or less it is preferred, further preferably 0.4 g / cm ³ or less, preferably specifically is 0.01 g / cm ³ or more 0.5 g / cm ³ or less, 0.05 g / cm ³ or more zero. More preferably, it is 4 g / cm ³ or less.

Although the present invention has been described based on the preferred embodiments, the absorbent article of the present invention is not limited to the above-described embodiments, and can be appropriately modified.
For example, the above embodiment is an example in which the present invention is applied to the panty liner 1. Instead, the present invention is applied to other absorbent articles, for example, sanitary napkins, incontinence pads, disposable diapers, and the like. Is also good.

  Further, in the above-described panty liner 1, as shown in FIG. 2, the lower layer member in contact with the topsheet 2 is the lower layer sheet 5, but may be other than the lower layer sheet 5. For example, in an absorbent article having no lower layer sheet 5, the lower member in contact with the top sheet 2 may be the absorber 4.

  Further, in the above-mentioned panty liner 1, as shown in FIGS. 1 and 3, a topsheet having an uneven structure is used as the topsheet 2, but a flat topsheet having no uneven structure may be used. In addition, in the surface sheet 2 having the concavo-convex structure of the panty liner 1 described above, as shown in FIGS. 1 and 3, the intermediate region 23 c having a fiber density lower than the fiber density of the top region 23 a and the fiber density of the bottom region 23 b. Although it extends continuously in the vertical direction X of the panty liner 1, it may extend intermittently.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such embodiments.

[Example 1]
(1) Preparation of Card Web and Nonwoven Fabric Precursor Lyocell fiber (trade name: Tencel, manufactured by Lenzing Co., Ltd.) which is a non-heat-fusible hydrophilic fiber, latent crimpable fiber (L (V) (trade name), Using 2.2 dtex × 51 mm (manufactured by Daiwa Spinning Co., Ltd.), these two types of fibers were defibrated and mixed by a card method to produce a card web.
Thereafter, high-pressure water was sprayed on the card web, and the fibers were entangled to prepare a nonwoven fabric precursor.
(2) Heat treatment The nonwoven fabric precursor was placed in a thermostatic dryer and heat-treated at 120 ° C ± 5 ° C for 15 seconds. As a result, the spirally crimped fiber was developed in the latently crimpable fiber, and the spirally crimped fiber was fused. Thus, the desired topsheet of Example 1 was obtained. With respect to the obtained topsheet of Example 1, the blending ratio of the hydrophilic fibers with respect to the whole constituting fibers was 90% by mass, the blending ratio of the spirally crimped fibers with respect to the whole constituting fibers was 10% by mass, and the topsheet was obtained. Had a basis weight of 35 g / m ² . The topsheet of Example 1 had neither a ridge nor a concave portion, and the topsheet of Example 1 had a flat shape.

[Example 2]
Using the same lyocell fiber and spirally crimped fiber as the fibers constituting the topsheet of Example 1, the intended topsheet of Example 2 was obtained through the same steps as the topsheet of Example 1. Regarding the obtained topsheet of Example 2, the blending ratio of the hydrophilic fibers with respect to the whole constituting fibers was 70% by mass, the blending ratio of the spirally crimped fibers with respect to the whole constituting fibers was 30% by mass, and the topsheet was obtained. Had a basis weight of 35 g / m ² .

[Example 3]
Using the same lyocell fiber and spirally crimped fiber as the fibers constituting the topsheet of Example 1, the same topsheet of Example 3 was obtained through the same steps as the topsheet of Example 1. Regarding the obtained topsheet of Example 3, the blending ratio of the hydrophilic fibers with respect to the whole constituting fibers was 50% by mass, the blending ratio of the spirally crimped fibers with respect to the whole constituting fibers was 50% by mass, and the topsheet was obtained. Had a basis weight of 35 g / m ² .

[Comparative Example 1]
Using only the same lyocell fiber as the fiber constituting the topsheet of Example 1, the same topsheet of Comparative Example 1 was obtained through the same steps as the topsheet of Example 1. With respect to the obtained topsheet of Comparative Example 1, the blending ratio of the hydrophilic fibers with respect to the whole constituting fibers was 100% by mass, and the basis weight of the topsheet was 35 g / m ² .

[Evaluation]
The topsheet was removed from a commercially available panty liner (trade name "Laurier Kirei Style", manufactured by Kao Corporation), and the topsheets of Examples 1 to 3 and Comparative Example 1 were placed instead. A panty liner for evaluation was produced by fixing the periphery of the top sheet of Examples 1 to 3 and Comparative Example 1 and the panty liner from which the top sheet was removed, around the second sheet as the lower layer side sheet. About the produced panty liner, fluffiness evaluation and liquid return amount evaluation were measured by the following methods. Further, for the topsheets of Examples 1 to 3 and Comparative Example 1, the compression work was measured to evaluate the texture. The results are shown in Table 1 below.

[Fuzziness evaluation]
A disk (diameter 70 mm, 350 g) whose surface is covered with urethane foam (urethane foam manufactured by Inotec Co., Ltd., trade name: Malt filter MF-30 type, thickness 0.5 mm), a position where the center of the disk is shifted 20 mm from the rotation axis. A test machine attached to the rotating shaft was prepared. The panty liner was fixed on a tester table with the topsheet facing upward. Next, the disk was placed on a surface sheet of a sample to which the disk was fixed, and the rotating shaft was rotated to rotate the disk around the sample. Circumferential movement was performed for 10 cycles, with clockwise twice and counterclockwise twice as one cycle. The peripheral speed at this time was about 3 seconds per rotation. With respect to the sample after the rotation, the fibers adhering to the urethane foam of the disk were collected with tweezers, the weight of the collected fibers was measured, and this was evaluated for fluffing. The lower the weight of the collected fiber, the less fluff.

[Evaluation of liquid return amount]
With a load of 5 g / cm ² applied to the entire area of the skin-facing surface (top sheet side) of the panty liner to be evaluated, 0.5 g of pseudo-blood was injected from the center of the skin-facing surface, and 1 Let stand for minutes. One minute later, the load is removed, and a filter paper having a rectangular shape in a plan view and cut into a size of 60 × 80 mm is placed on a portion of the panty liner facing the skin centered on the pseudo-blood injection portion. , A load of 3 g / cm ² was applied to the panty liner, and left in that state for 10 seconds. Ten seconds later, the filter paper was removed from the panty liner, and the weight (filter paper weight after liquid absorption) was measured. From the previously measured filter paper weight before liquid absorption (initial filter paper weight), the target liquid return amount was calculated by the following formula. Was calculated. The liquid return amount is an index of the smoothness and feel of the wearer when worn, and the smaller the numerical value of the liquid return amount, the higher the liquid absorbency of the top sheet, the easier it is to obtain the smoothness, and high evaluation. Becomes
Liquid return amount (mg) = filter paper weight after absorption-initial filter paper weight

[Compression work amount WC]
The compression work amount WC was measured using a KES FB3-AUTO-A type apparatus manufactured by Kato Tech Co., Ltd. under the conditions of a pressurized area of 2 cm ² , a compression speed of 0.02 mm / sec, and an upper limit load of 50 gf / cm ² . The larger the value of the compression work amount WC is, the softer the work is, and it is evaluated that the texture is good.

  As is clear from the results shown in Table 1, the surface sheets of Examples 1 to 3 have a larger value of the compression work WC, are softer and have a better texture than the surface sheets of Comparative Example 1. Was. Further, it was found that the topsheets of Examples 1 to 3 had a smaller liquid return amount than the topsheet of Comparative Example 1. Furthermore, the surface sheets of Examples 1 to 3 were found to have a lower weight of the collected fibers and less fluff than the surface sheet of Comparative Example 1. From these results, the topsheets of Examples 1 to 3 have a softer and softer touch than the topsheet of Comparative Example 1, are less likely to fluff after prolonged wearing, and have a liquid residue on the topsheet. It is unlikely to occur, and it can be expected that discomfort to the wearer is suppressed.

DESCRIPTION OF SYMBOLS 1 Panty liner 2 Top sheet 2f1 Hydrophilic fiber 2f2 Spiral crimped fiber 21 Convex section 22 Concave section 23a Top section 23b Bottom section 23c Intermediate section 3 Back sheet 4 Absorber 5 Lower layer sheet 6 Depression 7 Peripheral part 100 Manufacturing device 8 Extension part 81,82,87 Concavo-convex roll 83,84,89 Large diameter convex part 85,86 Spacer

Claims (3)

A liquid-permeable top sheet forming a skin-facing surface; and a lower sheet on a non-skin-facing surface side of the top sheet, wherein the lower sheet is disposed between the top sheet and the absorber. An absorbent article having a width direction orthogonal to the longitudinal direction and the longitudinal direction corresponding to the wearer's front-back direction,
The topsheet includes non-heat-fusible hydrophilic fibers and heat-fusible helical crimped fibers,
The lower layer side sheet includes a heat-fusible fiber,
The hydrophilic fiber has a compounding ratio of 50% by mass or more with respect to the entire fiber constituting the topsheet,
In the topsheet, the spirally-crimped fibers are fused together, or the spirally-crimped fiber is fused to the hydrophilic fiber,
The helically crimped fibers of the top sheet and the heat-fusible fibers of the lower layer side sheet are fused together,
The basis weight of the lower layer sheet is higher than the basis weight of the basis weight and the absorber of the topsheet,
The topsheet is formed in a concavo-convex structure in which streaky ridges and concave ridges extending in the longitudinal direction are alternately arranged in the width direction,
An absorbent article wherein an intermediate region between a top region of the ridge and a bottom region of the concave ridge has a lower density than a density of the top region and a density of the bottom region. The ratio of the basis weight of the lower sheet to the basis weight of the top sheet is 1.01 or more and 2.0 or less,
The absorbent article according to claim 1, wherein a ratio of a basis weight of the lower layer side sheet to a basis weight of the absorber is 1.01 or more and 2.0 or less. The basis weight of the lower layer side sheet is 10 g / m ² or more and 60 g / m ² or less;
The basis weight of the absorber is 10 g / m ² or more and 80 g / m ² or less;
The absorbent article according to claim 1, wherein the topsheet has a basis weight of 5 g / m ² or more and 40 g / m ² or less.

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