JP2012010972A - Thin absorbent article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorbent article having a thin thickness before absorbing liquid, has a sufficient liquid absorbing capacity, and has an absorbent body unlikely to cause deformation such as twisting, during the use of the article.SOLUTION: The absorbent article has a liquid permeable front surface sheet, a liquid impermeable back surface sheet, and an absorbent body located between both the sheets. The absorbent body includes a layered body of at least two absorbent layers and at least three liquid permeable layers. An absorbent layer is disposed between a liquid permeable layer and a liquid permeable layer. The absorbent layer contains water absorbent fibers and super absorbent polymer. The liquid permeable layer is formed from stretchable nonwoven fabric.

Description

  The present invention relates to absorbent articles such as sanitary napkins and disposable diapers. In particular, the present invention relates to an absorbent article that is thin before liquid absorption but has a sufficient liquid absorption capacity and is less likely to be deformed such as twisting in the absorbent body during use.

  2. Description of the Related Art Known absorbents used in absorbent articles such as sanitary napkins and disposable diapers are those in which a mixture of short fibers and superabsorbent resin particles is wrapped with a wrap material such as tissue. For example, Patent Document 1 discloses an absorbent body excellent in liquid absorption speed and flexibility and an absorbent article including the absorbent body. The absorbent body includes a web and absorbent polymer particles contained therein. At least one core layer mainly composed of the above, the web is formed of short fibers having crimps other than pulp fibers, the short fibers are not fused together, and the core layer is a fiber other than the short fibers. It is characterized by not containing substantially. Patent Document 1 also discloses that one or a plurality of sheet materials such as paper and non-woven fabric are provided on and / or below the web in order to improve the spot absorbability of the liquid and to improve the shape retention of the web. Sheet-like absorption in which the web is sandwiched and fixed between a pair of sheet materials obtained by overlapping or covering, joining the web and the sheet material with an adhesive applied to the sheet material, or heat-sealing. The body is disclosed.

JP 2008-125603 A

  However, in the absorbent body disclosed in Patent Document 1, the short fibers are not fused to each other, and the core layer does not substantially contain fibers other than the short fibers. Is likely to occur. In addition, in order to prevent deformation, it is disclosed that a layer such as a nonwoven fabric is superimposed on and / or below the web. However, in a structure in which one web layer is simply sandwiched between a pair of liquid-permeable layers, Since the swelling amount of the absorbent polymer per unit becomes large, twisting or peeling occurs, and there is a high risk of leakage due to a decrease in absorbability. Moreover, if the amount of short fibers is increased in order to suppress the movement after swelling of the absorbent polymer, it becomes difficult to reduce the weight and thickness. Further, there is no mention of fixing the absorbent polymer, and particularly when the absorbent polymer is not fixed, the absorbent polymer easily moves, and there is a high risk of discomfort during wearing and leakage due to a decrease in absorption performance. In addition, when fixing through an adhesive agent, at least a part of the surface of the absorbent polymer is covered, and there is a high risk of leakage due to a decrease in absorption performance.

  The inventors of the present invention solve the above-mentioned problems of the prior art by making the absorbent body a multilayer structure in which a layer containing a water-absorbing fiber and a highly water-absorbent resin and a liquid-permeable layer are alternately laminated. The present invention has been completed.

That is, the present invention is an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body positioned between the two sheets, wherein the absorbent body has at least two absorbent layers and at least It consists of a laminate of three liquid permeable layers, the absorbent layer is disposed between the liquid permeable layer and the liquid permeable layer, the absorbent layer contains water absorbent fibers and a highly water absorbent resin, and is liquid permeable. The layer is made of an extensible nonwoven fabric.
The liquid-permeable layer is preferably partially bonded to the liquid-permeable layer adjacent in the thickness direction.
The junction between the liquid permeable layer and the liquid permeable layer is preferably continuous in the width direction of the absorber.
Preferably, the absorbent layer is divided into a plurality of portions in the length direction, and the liquid permeable layers adjacent to each other in the thickness direction are joined in a region between the divided absorbent layer and the absorbent layer.
Preferably, the liquid permeable layer is made of a nonwoven fabric of synthetic fibers, and at least a part of the synthetic fibers and the water absorbent fibers are bonded at the interface between the liquid permeable layer and the water absorbent layer.
The stretchable nonwoven fabric preferably has an elongation of 1.4 times or more.
The absorbent body is preferably a laminate of an absorbent layer and a liquid permeable layer that is tri-folded so that the liquid permeable layer is on the outside.
The absorbent article preferably further includes a wrapping material that wraps the absorbent body.
The fiber length of the water absorbent fiber is preferably 20 to 70 mm.
Preferably, the absorber is molded by being given water or water vapor.
The superabsorbent resin is preferably composed of two or more superabsorbent resins having different absorption performances, and one of the superabsorbent resins has a Vortex absorption rate within 20 seconds and an absorption amount under a load of 2.0 kPa. It is 25 g / g or more.

  In the absorbent article of the present invention, the absorbent body has a multilayer structure in which water-absorbing fibers, a layer containing a highly water-absorbent resin, and a liquid-permeable layer are alternately laminated, that is, the highly water-absorbent resin is swollen. By arranging the layer and the layer for maintaining the form separately, it is possible to achieve both absorption and form maintenance, and to reduce the thickness and weight of the absorber. Therefore, although the absorbent article of the present invention is thin before liquid absorption, it has a sufficient liquid absorption capacity and is less likely to cause discomfort due to deformation of the absorbent body during use.

It is a top view of one embodiment of the absorptive article of the present invention. It is sectional drawing of one embodiment of the absorbent article of this invention. It is sectional drawing of another embodiment of the absorbent article of this invention. It is a top view of one embodiment of an absorber by which an absorptive layer was divided into plurality in the length direction. It is sectional drawing of one embodiment of the absorber with which the absorptive layer was divided | segmented into plurality in the length direction. It is sectional drawing of another embodiment of the absorber with which the absorptive layer was divided | segmented into plurality in the length direction.

The present invention will be described below with reference to the drawings, but the present invention is not limited to those shown in the drawings.
FIG. 1 is a plan view of one embodiment of the absorbent article of the present invention, showing a state in which a part of a sheet or layer is broken so that the inside can be partially seen. FIG. 2 is a sectional view taken along line XX ′.
The absorbent article 1 of the present invention has a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and an absorbent body 4 positioned between both sheets, and the absorbent body 4 has at least two absorbent layers. 5 and at least three liquid-permeable layers 6, and the absorbent layer 5 is disposed between the liquid-permeable layer 6 and the liquid-permeable layer 6.

  FIG. 2 shows an absorbent body having a five-layer structure in which two absorbent layers 5 are arranged between three liquid-permeable layers 6. The absorbent body is composed of four liquid-permeable layers. It may be a 7-layer structure composed of 3 absorbent layers, a 9-layer structure composed of 5 liquid-permeable layers and 4 absorbent layers, or a multilayer structure having more layers It may be. By separately arranging a layer that swells the superabsorbent resin (absorbent layer 5) and a layer that maintains the form (liquid permeable layer 6), both the absorbency and the form maintenance are achieved, and the thin and compact design prevents leakage. Prevention becomes possible. In addition, since the amount of the superabsorbent resin per layer is smaller than when the absorbent layer 5 is a single layer, the fiber stretches following the superabsorbent resin within the layer even after the superabsorbent resin swells. Movement of the superabsorbent resin can be suppressed, and deformation is less likely to occur during mounting. Moreover, by alternately laminating the liquid permeable layer 6 and the absorbent layer 5, an interface is formed, a liquid flow is formed, and the liquid can be easily transferred to the superabsorbent resin. Moreover, by making the absorptive layer 5 into two or more layers, each absorptive layer 5 becomes thin and the liquid tends to reach the highly water-absorbent resin. Moreover, since a thin absorptive layer becomes thin [absorptive fiber], a super absorbent polymer can be disperse | distributed between absorptive fibers.

Moreover, as shown in FIG. 3, the absorber 4 may be a laminate of the absorbent layer 5 and the liquid permeable layer 6 that is folded in three so that the liquid permeable layer 6 comes outside. The absorber having such a structure has an advantage that alignment during manufacture is easy. Further, when the absorbent layer 5 is overlapped with the liquid permeable layer 6 and folded into a plurality of layers, leakage of the superabsorbent resin is less likely to occur.
Further, an absorbent body having a multilayer structure may be produced by laminating the absorbent layer 5 on the liquid permeable layer 6 and winding it. According to this manufacturing method, the layer structure can be easily formed, and the process can be simplified.

  The liquid permeable layer 6 is a layer for separating the absorbent layer 5 into a plurality of layers, and is made of an extensible nonwoven fabric. Here, extensibility means that the liquid-permeable layer 6 can extend following the swelling of the superabsorbent resin contained in the absorbent layer 5 when the absorber absorbs the liquid. Preferably, the extensible non-woven fabric has an elongation of 1.4 times or more, more preferably 1.4 to 2.5 times or more. Here, the elongation refers to a value obtained by dividing the length when a 25 mm wide nonwoven fabric is pulled with a force of 1.0 N by the original length. Since the liquid-permeable layer 6 has extensibility, the liquid-permeable layer 6 can follow the swelling of the absorbent layer 5 and does not inhibit the swelling of the highly water-absorbent resin. Can be used to the maximum. Examples of the stretchable nonwoven fabric include a nonwoven fabric subjected to a biting gear roll treatment, a nonwoven fabric composed of crimped fibers, and a stretchable nonwoven fabric including elastic fibers such as polyurethane, and a nonwoven fabric subjected to a biting gear roll treatment is preferable. Examples of the nonwoven fabric include air-through nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, thermal bond nonwoven fabric, melt blown nonwoven fabric, and needle punch nonwoven fabric. A non-woven fabric of synthetic fibers is preferable. By using a synthetic fiber non-woven fabric, the liquid-permeable layers 6 adjacent in the thickness direction can be easily joined to each other by thermal fusion. In addition, the synthetic fiber and the water-absorbing fiber, and the synthetic fiber and the highly water-absorbent resin are fused together to prevent excessive deformation of the absorbent body even when it is worn or wet. It is possible to suppress or reduce discomfort. Synthetic fibers include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, fibers of thermoplastic resins such as polyamide, and core-sheath type and side-by-side type composite fibers composed of combinations of these thermoplastic resins. Preferably, it is a heat-fusible fiber. Examples of the heat-fusible fiber include a polyester / polyethylene core-sheath type composite fiber. The fineness of the fiber is preferably 0.01 to 20 dtex, more preferably 1 to 10 dtex. If the fineness is too large, the number of fibers will be reduced and it will be difficult to hold the highly water-absorbent resin between the fibers, and it will be easy to inhibit the swelling of the highly water-absorbent resin. Conversely, if it is too small, the stiffness of the fiber itself will be lost. It becomes difficult to maintain a skeleton structure composed of fibers. The fiber length is preferably 30 to 80 mm, more preferably 40 to 70 mm. If the fiber length is too long, it will be difficult to handle in production, and if it is too short, the number of heat-sealed portions will decrease and it will be difficult to form a skeleton structure composed of fibers.

The basis weight of the liquid permeable layer 6 is not limited, but is preferably 10 to 50 g / m ² , more preferably 15 to 40 g / m ² . If the basis weight of the liquid permeable layer 6 is too large, it will be difficult to follow the swelling of the absorber (highly water-absorbent resin), and conversely if too small, the liquid permeable layer 6 will be easily broken.

  It is preferable that the liquid permeable layer 6 is partially joined to the liquid permeable layer adjacent in the thickness direction. Since the liquid permeable layers adjacent to each other in the thickness direction are partially joined, the movement of the absorbent layer can be suppressed, and the uncomfortable feeling when the absorbent article is mounted can be reduced. The partial bonding between the liquid permeable layers adjacent to each other in the thickness direction may be point bonding, line bonding, or surface bonding. Preferably, as shown in FIGS. The junction between the layer and the liquid permeable layer is continuous in the width direction (CD) of the absorber. Such a joint has a large effect of suppressing the movement of the absorbent layer. As a joining method, any method such as adhesion using an adhesive or heat fusion may be used. However, heat fusion is preferred, and heat embossing can be suitably used.

  The absorptive layer 5 contains a water absorbing fiber and a highly water absorbent resin. Further, the absorbent layer 5 may contain a resin other than the highly water-absorbent resin and fibers other than the water-absorbent fiber as long as the effects of the present invention are not impaired.

  Examples of the water-absorbing fiber include flap-like pulp, chemical pulp, cellulose fiber, rayon, and acetate fiber. If a highly water-absorbing resin is placed in the water-absorbing fiber, the hydrogen absorption between the water-absorbing fibers and between the water-absorbing fiber and the high water-absorbing resin is released by liquid absorption, allowing the high water-absorbing resin to freely swell. Since the swelling of the water-absorbent resin is not hindered, the high water-absorbent resin absorption can be used effectively, and the absorber can be reduced in weight.

  Although the fiber length of a water absorbing fiber is not limited, Preferably it is 20-70 mm. If the fiber length is too long, the flow of liquid is suppressed, while if it is too short, it will be difficult to get entangled and it will be difficult to maintain the shape, so that the superabsorbent resin will easily fall off.

  As the water absorbing fiber, acetate fiber is preferable. Since acetate fibers have hydroxyl groups, hydrogen bonds are generated between the acetate fibers and between the acetate fibers and the highly water-absorbent resin, thereby preventing the movement of the highly water-absorbent resin and maintaining the thickness (form) when dry. Is possible. In addition, since the hydroxyl group is partially substituted with acetic acid group, the fiber is difficult to hold the liquid, and the liquid transfer property to the highly water-absorbent resin is increased. Reduction and suppression of stuffiness are possible. Using acetate fibers with a Y cross-section increases the specific surface area, which increases the contact area between the fibers and with the superabsorbent resin, easily forms a bond, prevents the superabsorbent resin from moving, and is being worn. It is possible to prevent discomfort. Moreover, since the capillary effect is easy to work, the diffusion of the liquid can be promoted. When the superabsorbent resin is disposed in the acetate fiber, hydrogen bonds between the fibers and between the fiber and the superabsorbent resin are released by liquid absorption, and the superabsorbent resin can freely swell. When the absorbent layer containing acetate fibers and the liquid-permeable layer are alternately arranged, the presence of the superabsorbent resin between the acetate fibers facilitates the transfer of the liquid to the superabsorbent resin, and at the same time between the fibers. The hydrogen bond is removed, and the fiber skeleton can be deformed following the swelling of the superabsorbent resin.

  A highly water-absorbent resin (hereinafter also referred to as “SAP”) has a three-dimensional network structure in which a water-soluble polymer is appropriately cross-linked, and absorbs water several hundred to 1,000 times, but essentially water. The water which is insoluble and once absorbed does not release even when a certain pressure is applied, and examples thereof include starch-based, acrylic acid-based, amino acid-based particulate, fibrous or foam-like polymers.

  The absorptive layer preferably contains two or more types of superabsorbent resins having different absorption performances, and at least one superabsorbent resin has a vortex absorption rate of 20 seconds or less and an absorption amount of 25 g / 2.0 kPa under load. g or more. Here, the Vortex absorption rate refers to the time for 2 g of SAP to absorb 50 g of physiological saline according to “Water absorption rate test method for highly water-absorbent resin” described in JIS K7224, and under a load of 2.0 kPa. Absorption amount refers to the amount of physiological saline absorbed per hour per 1 g of SAP under 2.0 kPa. When a high water absorption resin (hereinafter referred to as “first high water absorption resin”) having a Vortex absorption speed of 20 seconds or less and an absorption amount of 25 g / g or more under a load of 2.0 kPa is used, the space swells instantaneously. Since (thickness) is formed and the liquid permeability does not decrease even after swelling, the liquid can be accommodated in the absorbent body without causing a liquid pool on the surface, and leakage can be prevented.

  The superabsorbent resin used in combination with the first superabsorbent resin is preferably a superabsorbent resin having a large absorption capacity (hereinafter referred to as “second superabsorbent resin”). Since only the first superabsorbent resin is insufficient in absorption, the combined use of the second superabsorbent resin can suppress an increase in the amount of superabsorbent resin and can reduce the weight of the absorber. It becomes. The absorption mechanism when these two kinds of superabsorbent resins are used is as follows. (1) The liquid comes into contact with the absorber, and the fibers and the superabsorbent resin get wet. (2) The water absorption of the first superabsorbent resin is accelerated first, and the volume of the superabsorbent resin increases. Since the water-absorbent fibers have a degree of freedom between the fibers, the absorber thickness is recovered without inhibiting the increase in the volume of the highly water-absorbent resin, a temporary liquid storage space is formed, and spot absorption becomes possible. (3) Furthermore, after the incoming liquid is accommodated in the previously formed temporary accommodation space, the liquid spreads through the fibers, and the second superabsorbent resin has a relatively slow water absorption and a large amount of absorption. Absorbed. When these two types of superabsorbent resins are used in combination, the mass ratio of the first superabsorbent resin / second superabsorbent resin is preferably 5/95 to 50/50, more preferably 10/90. ~ 30/70.

Commercially available superabsorbent resins can be used. The particle diameter of the superabsorbent resin is not limited, but preferably, the particle diameter of the first superabsorbent resin is 250 to 350 μm, and the particle diameter of the second superabsorbent resin is 300 to 400 μm. It is. The water-absorbing fiber distance before the high water-absorbing resin swells is easier to hold the high water-absorbing resin if it is smaller than the particle diameter of the first high water-absorbing resin and the second high water-absorbing resin. The bulk density of the superabsorbent resin is not limited, but preferably, the bulk density of the first superabsorbent resin is 0.2 to 0.5 g / cm ³ and the second superabsorbent resin. The bulk density is 0.5-1.0 g / cm ³ , more preferably, the bulk density of the first superabsorbent resin is 0.3-0.4 g / cm ³ , and the second superabsorbent The bulk density of the conductive resin is 0.6 to 0.8 g / cm ³ . The bulk density is a value obtained by dividing the mass of the powder by the bulk volume occupied, and can be obtained by filling the powder in a container with a known volume and measuring the mass.

It is preferable that the absorptive layer is divided | segmented into plurality in the length direction.
FIG. 4 is a plan view of an embodiment of an absorbent body in which the absorbent layer is divided into a plurality of portions in the length direction, with a part of the liquid permeable layer 6a broken so that the inside can be partially seen. Indicates. FIG. 5 is a cross-sectional view taken along line YY ′ of FIG. In the figure, MD indicates the length direction, CD indicates the width direction, and TD indicates the thickness direction. The absorptive layer 5 is divided into three in the length direction. By dividing | segmenting, the area | region 11 in which an absorptive layer does not exist becomes a bending start point, and the flexible deformation | transformation of an absorbent article is enabled. In the embodiment shown in FIG. 5, in the region 11 between the absorbent layer 5 and the absorbent layer 5, the liquid permeable layers 6 adjacent to each other in the thickness direction (the liquid permeable layer 6a and the liquid permeable layer 6b, the liquid permeable layer). The permeable layer 6b and the liquid permeable layer 6c) are joined. Such a joint can be a starting point for bending, suppress the movement of the absorbent layer, and reduce the uncomfortable feeling when the absorbent article is mounted.

  FIG. 6 is a cross-sectional view of another embodiment of an absorbent body in which the absorbent layer is divided into a plurality of parts in the length direction. As shown in FIG. 6, the absorbent layers 5 adjacent to each other in the length direction are not completely separated from each other, and the absorbent layers 5 adjacent to each other in the length direction have a smaller basis weight than other portions (low It may be connected at a basis area 5c. In such a case, the portion 5c with a small basis weight serves as a bending start point, and enables flexible deformation of the absorbent article.

  When producing an absorbent body in which the absorbent layer is divided into a plurality of parts in the length direction, a plurality of absorbent layers divided in advance may be arranged on the nonwoven fabric with a gap between them. After disposing the absorbent layer, only the absorbent layer may be cut.

The thickness of the absorbent layer 5 is preferably 1 to 20 mm, more preferably 2 to 10 mm. Although the fabric weight of the absorptive layer 5 is not limited, Preferably it is 10-1000 g / m < ² >, More preferably, it is 100-500 g / m < ² >. If the thickness or basis weight of the absorbent layer 5 is too large, the fixing of the superabsorbent resin and the increase in the swelling volume become large, and it becomes difficult to follow the deformation of the absorbent body of the liquid permeable layer 6. The capacity becomes small.

  At the interface between the liquid permeable layer 6 and the absorbent layer 5, it is preferable that at least a part of the synthetic fiber and the water absorbent fiber are bonded. For example, the bonding may be performed by steaming the laminated body of the liquid permeable layer 6 and the absorbent layer 5 and thermally bonding the fibers constituting the liquid permeable layer 6 and the water absorbent fibers constituting the absorbent layer 5. Can be formed. Since at least a part of the fibers constituting the liquid-permeable layer 6 and the water-absorbing fibers constituting the absorbent layer 5 are combined, the thickness is kept thin in the mounted state before excretion, and deformation is unlikely to occur. Even after the liquid absorbs the liquid and the highly water-absorbent resin swells, if at least a part of the fibers constituting the liquid-permeable layer 6 and the water-absorbing fibers constituting the absorbent layer 5 are bonded to each other, deformation is further prevented. It is effective for.

  It is preferable that the absorber 4 is shape | molded by providing water or water vapor | steam. The application of water or water vapor can be performed by, for example, water spraying or steam spraying. By applying water or water vapor, the water-absorbing fibers and between the water-absorbing fibers and the superabsorbent resin are fixed by hydrogen bonds. Thereby, an absorber can be shape | molded thinly. Due to hydrogen bonding between the water-absorbing fibers and between the water-absorbing fibers and the highly water-absorbent resin, the thickness is kept thin in the mounted state before excretion, and deformation is unlikely to occur.

  Steam spraying can also simultaneously apply moisture, heat, and force, so that hydrogen bonds are formed in the water-absorbing fibers, and heat fusion is formed in the liquid-permeable layer made of thermoplastic fibers, Since the fibers are fixed between the fibers and between the fibers and the superabsorbent resin, and the fibers are scraped, the fibers and the superabsorbent resin and the superabsorbent resin are physically easily entangled, thereby maintaining a low thickness and a superabsorbent polymer. Prevention of the movement of the resin is achieved, and the uncomfortable feeling during mounting can be reduced. Suction may be used during the steam spraying process.

  The thickness of the absorber 4 is preferably 0.5 to 10 mm, more preferably 1 to 5 mm. If the thickness is too thick, the thickness of the absorbent article as a whole will be thick, so that a sense of incongruity will occur at the time of wearing. Conversely, if it is too thin, it will be difficult to secure the absorption capacity and the strength of the absorber will also be weakened.

  In the absorbent article of the present invention, the absorbent body 4 may be further wrapped with a wrap material 9 as shown in FIG. By wrapping with the wrapping material 9, it is possible to prevent the superabsorbent resin from falling off the absorbent layer 5. The material constituting the wrapping material 9 is made of tissue, cellulose such as cotton, regenerated cellulose such as rayon and fibril rayon, semi-synthetic cellulose such as acetate and triacetate, fibrous polymer, thermoplastic hydrophobic chemical fiber, etc. Woven or non-woven fabric. Among these, SMS nonwoven fabrics (spunbond / meltblown / spunbond nonwoven fabric) are preferable.

  The absorber 4 can be manufactured as follows. By placing the absorbent layer 5 on the liquid permeable layer 6, placing the liquid permeable layer 6 thereon, placing the absorbent layer 5 thereon, and placing the liquid permeable layer 6 thereon, An absorber having a five-layer structure can be manufactured. When producing an absorber having a seven-layer structure, the absorbent layer 5 is again placed on the absorber having a five-layer structure, and the liquid-permeable layer 6 is placed thereon. By repeating the placement of the absorbent layer 5 and the liquid permeable layer 6, a multilayer absorber can be produced. As the absorbent layer 5, a mixture of a water absorbent fiber and a highly water absorbent resin may be placed on the liquid permeable layer 6, but the opened water absorbent fiber is placed on the liquid permeable layer 6. However, a highly water-absorbing resin may be sprayed thereon. At that time, water may be sprayed on the water-absorbent fibers before the highly water-absorbent resin is sprayed. If water is sprayed, the movement of the sprayed superabsorbent resin is suppressed, and dissipation can be prevented. After the water-absorbing fiber and the superabsorbent resin are placed on the liquid-permeable layer 6, as shown in FIG. May be. Steam may be blown onto the laminate of the liquid permeable layer 6 and the absorbent layer 5. By spraying the steam, each material constituting the laminate is fixed, and the laminate is formed thin. Instead of spraying steam, the laminate may be pressed to be thin. The laminate may be further wrapped with a wrap material 9 such as tissue or SMS nonwoven fabric.

  The liquid-permeable surface sheet 2 constituting the absorbent article 1 of the present invention has a function of allowing liquid excretion from the body such as menstrual blood and urine to pass through the absorbent body 4 provided in the lower layer, and is liquid-free. This is for holding the absorber 4 by sandwiching the absorber 4 with the permeable back sheet 3. The liquid permeable top sheet 2 is wholly or partially liquid permeable, and the liquid permeable region includes a resin film having a large number of liquid permeable holes, a net-like sheet having a large number of meshes, and a liquid permeable surface. It is formed of a nonwoven fabric or a woven fabric. As the resin film and the net-like sheet, those formed of polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), or the like can be used. Moreover, as a nonwoven fabric, the spunlace nonwoven fabric formed from cellulose fibers, such as rayon, a synthetic resin fiber, the air through nonwoven fabric formed from the synthetic resin fiber, etc. can be used. Moreover, as a raw material, natural products capable of biodegradability such as polylactic acid, chitosan, polyalginic acid and the like can be used. In addition, a large number of liquid-permeable holes may be formed, and a silicone-based or fluorine-based water-repellent oil agent may be applied to make it difficult for body fluids to adhere to the outer surface.

The basis weight of the liquid-permeable topsheet 2, but are not limited to, preferably 10 to 50 g / ^{m 2,} more preferably from 20 to 40 g / ^{m 2.} If the basis weight of the liquid-permeable surface sheet 2 is too small, the surface strength is not sufficiently obtained and may be broken during use. On the other hand, if it is too large, excessive wobbling will occur, causing a sense of incongruity during use. Furthermore, when used for a long time, the liquid is held by the liquid-permeable surface sheet, and the liquid is kept in a solid state and feels uncomfortable.

  The liquid-impermeable back sheet 3 constituting the absorbent article 1 of the present invention has a function of preventing liquids such as menstrual blood and urine absorbed by the absorber from leaking outside. A material is used that can prevent the liquid from leaking out. Moreover, by using a material that does not allow liquid to pass through but is breathable, it is possible to reduce stuffiness during wearing and to reduce discomfort during wearing. Examples of such a material include a liquid-impermeable film mainly composed of polyethylene (PE), polypropylene (PP), etc., a breathable film, and a composite in which a liquid-impermeable film is laminated on one side of a nonwoven fabric such as spunbond. A sheet etc. are mentioned. Preferably, a hydrophobic nonwoven fabric, a water-impermeable plastic film, a laminate sheet of a nonwoven fabric and a water-impermeable plastic film, or the like can be used. Alternatively, an SMS nonwoven fabric in which a melt-blown nonwoven fabric having high water resistance is sandwiched between strong spunbond nonwoven fabrics may be used.

  The absorbent article 1 can be manufactured by superimposing the liquid-permeable top sheet 2, the liquid-impermeable back sheet 3 and the absorber 4 by a conventional method. Specifically, for example, the absorbent body 4 is placed on the liquid-impermeable back sheet 3, and the liquid-permeable surface sheet 2 is placed thereon, and by adhesive or heat fusion, preferably by heat embossing, The absorbent article 1 can be produced by partially joining the liquid-permeable top sheet 2 and the liquid-impermeable back sheet 3 and cutting them into desired dimensions and shapes.

Next, as a preferable specific example of the manufacturing method of the absorbent article 1 of the present invention, a specific example of the manufacturing method of the absorbent article 1 shown in FIG. 3 will be described, but the present invention is not limited to this specific example. Absent.
First, an air-through nonwoven fabric (weight per unit area: 25 g / m ² ) made of a polyester / polyethylene composite fiber that has been bitten and rolled as a stretchable nonwoven fabric for the liquid-permeable layer 6 is cut into a length of 300 mm and a width of 210 mm (1 g). 2 g of acetate fiber tow opened to the same size is cut into a length of 50 mm and laminated with a basis weight of 32 g / m ² . Water was sprayed on the acetate fiber, and 9 g of a superabsorbent resin composed of an acrylic acid (salt) polymer having a vortex absorption rate of 3 seconds, an absorption amount of 26 g / g under a load of 2.0 kPa, and a bulk density of 0.36 g / cm ^3. 1 g of superabsorbent resin made of acrylic acid (salt) polymer having a basis weight of 159 g / m ² , a Vortex absorption rate of 30 seconds, an absorption of 33 g / g under a load of 2.0 kPa, and a bulk density of 0.69 g / cm ³ Spray at 18 g / m ² . A laminate of the nonwoven fabric, acetate fiber, and superabsorbent resin is folded in three in the width direction and formed into a width of 70 mm. Thereafter, steam is blown (pressure 0.7 MPa, clearance 2 mm) to produce an absorber (mass 14.1 g, thickness 2.50 mm, basis weight 744 g / m ² , density 0.30 g / cm ³ ). The absorbent body is wrapped with a wrap material 9 (SMS nonwoven fabric) and placed on a ventilation film (weight per unit area: 18 g / m ² ) made of polyethylene for the liquid-impermeable back sheet 3, on which the liquid-permeable top sheet 2 is placed. The air through nonwoven fabric (25 g / m < ² >) of a polyester / polyethylene core-sheath composite fiber is piled up. With the above, the absorbent article shown in FIG. 3 can be produced.

  The thickness of the absorbent article is preferably 1 to 20 mm, more preferably 2 to 15 mm. If the thickness is too thick, the feeling of wearing is worsened. Conversely, if the thickness is too thin, it is difficult to secure the absorption capacity.

  The absorbent article of the present invention is preferably used as a sanitary napkin, a disposable diaper or the like. When used as a sanitary napkin or disposable diaper, it is worn so that the surface of the liquid-permeable surface sheet touches the wearer's skin. The shape of the absorbent article is, for example, a sanitary napkin, a rectangle, an ellipse, a saddle, and a so-called wing that prevents misalignment with shorts. If it is, it will not specifically limit. The total dimension of the outer shape is preferably 100 to 500 mm in the longitudinal direction, and more preferably 150 to 350 mm. Moreover, 30-200 mm is preferable and, as for a transversal direction, it is preferable that it is 40-180 mm.

  The absorbent article of the present invention can be suitably used for sanitary napkins, disposable diapers and the like.

DESCRIPTION OF SYMBOLS 1 Absorbent article 2 Liquid-permeable surface sheet 3 Liquid-impermeable back sheet 4 Absorber 5 Absorbent layer 6 Liquid-permeable layer 9 Wrapping material

Claims (11)

  An absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body positioned between the two sheets, wherein the absorbent body has at least two absorbent layers and at least three liquid-permeable layers. A laminate of layers, the absorbent layer is disposed between the liquid permeable layer and the liquid permeable layer, the absorbent layer includes a water absorbent fiber and a super absorbent polymer, and the liquid permeable layer is an extensible nonwoven fabric An absorbent article comprising:   The absorbent article according to claim 1, wherein the liquid permeable layer is partially bonded to a liquid permeable layer adjacent in the thickness direction.   The absorbent article according to claim 2, wherein a joint between the liquid permeable layer and the liquid permeable layer is continuous in the width direction of the absorbent body.   The absorbent layer is divided into a plurality of parts in the length direction, and the liquid permeable layers adjacent to each other in the thickness direction are joined in a region between the divided absorbent layer and the absorbent layer. The absorptive article according to any one of claims 1 to 3.   The liquid permeable layer is made of a nonwoven fabric of synthetic fibers, and at least a part of the synthetic fibers and the water absorbent fibers are bonded at the interface between the liquid permeable layer and the water absorbent layer. The absorbent article of Claim 1.   The absorbent article according to any one of claims 1 to 5, wherein the stretchable nonwoven fabric has an elongation of 1.4 times or more.   The absorbent body according to any one of claims 1 to 6, wherein the absorbent body is a laminate of the absorbent layer and the liquid permeable layer, which is folded in three so that the liquid permeable layer comes outside. Absorbent articles.   The absorbent article according to any one of claims 1 to 7, wherein the absorbent article further includes a wrapping material that wraps the absorbent body.   The absorbent article according to any one of claims 1 to 8, wherein the fiber length of the water-absorbent fibers is 20 to 70 mm.   The absorbent article according to any one of claims 1 to 9, wherein the absorbent body is formed by applying water or water vapor.   The superabsorbent resin is composed of two or more superabsorbent resins having different absorption performances, and one of the superabsorbent resins has a Vortex absorption rate within 20 seconds and an absorption amount of 25 g / g under a load of 2.0 kPa. It is the above, The absorbent article of any one of Claims 1-10 characterized by the above-mentioned.

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