JPWO2019130565A1 - Absorbent article - Google Patents

Abstract

The laminated non-woven fabric (10) of the absorbent article (1) of the present invention has a hydrophilic first layer (11) and a hydrophobic second layer (12). The first layer (11) is composed of non-heat-sealing fibers, and the second layer (12) is mainly composed of long fibers of heat-sealing fibers. The laminated non-woven fabric (10) has a thickness smaller than that of the peripheral portion, and partially has an interlayer bonding portion (16) in which the layers constituting the laminated structure (13) are bonded to each other in a plan view. The portion having the interlayer joint (16) is recessed from the second surface (10b) side toward the first surface (10a) side. In the interlayer joint (16), the constituent fibers of the first layer (11) maintain the fiber morphology, the constituent fibers (15) of the second layer (12) are melted, and a part of the melted constituent resin. However, it penetrates between the constituent fibers of the first layer (11) and solidifies. The laminated non-woven fabric (10) is arranged around the waist of the absorbent article (1) with the second surface (10b) facing the wearer's skin side.

Description

The present invention relates to an absorbent article and a sweat-absorbing sheet using a laminated non-woven fabric having a laminated structure in which a plurality of non-woven fabrics are laminated.

In absorbent articles such as disposable diapers and sanitary napkins, conventionally, a non-woven fabric having a laminated structure of two or more layers, a non-woven fabric having an uneven surface, and the like are used as constituent members. For example, Patent Document 1 describes that a sweat-absorbing sheet capable of absorbing the wearer's sweat is arranged at a portion of the disposable diaper that comes into contact with the wearer's skin, and the sweat-absorbing sheet includes a hydrophobic non-woven fabric and hydrophilicity. It is described that a laminated non-woven fabric having a laminated structure with a non-woven fabric and in which both non-woven fabrics are bonded to each other at a large number of heat-sealed portions recessed in a concave shape is used, and further, the laminated non-woven fabric wears the hydrophobic non-woven fabric. It is stated that it is placed toward the skin side of the person.

Patent Document 2 describes a unidirectional water-permeable non-woven fabric sheet having liquid permeability from a certain surface direction and not liquid permeability from the opposite direction as a laminated non-woven fabric suitable for a constituent member of an absorbent article. Further, as an embodiment of the unidirectional water-conducting non-woven fabric sheet, a non-woven fabric in which at least one layer is hydrophilic and the rest is non-woven fabric is described. Further, Patent Document 2 describes a method of laminating a plurality of non-woven fabrics and performing a heat fusion treatment by a thermal embossing roll as a method of manufacturing a laminated non-woven fabric, and further, as another manufacturing method, on a spunbonded non-woven fabric. Describes a method in which long fibers having a predetermined fineness are directly deposited, and then entanglement treatment is performed by means such as needle punching, water jet, ultrasonic sealing, or heat fusion treatment by heat embossing roll. Has been done.

Japanese Unexamined Patent Publication No. 2004-298467 Japanese Unexamined Patent Publication No. 2006-51649

The present invention is an absorbent article comprising a laminated nonwoven fabric having a laminated structure in which a plurality of fiber layers are laminated. The laminated non-woven fabric has a first surface which is one surface and a second surface which is the other surface, and is a hydrophilic first layer forming the first surface and a second surface side of the first layer. It has a hydrophobic second layer located in. The first layer is composed of non-heat-fused fibers. The second layer is mainly composed of heat-sealing fibers, which are long fibers. The laminated nonwoven fabric is smaller in thickness than the peripheral portion, and partially has an interlayer joining portion in which the layers constituting the laminated structure are bonded to each other in a plan view of the laminated nonwoven fabric. The portion having the interlayer joint is recessed from the second surface side toward the first surface side. The constituent fibers of the first layer at the interlayer joint maintain the fiber morphology. The constituent fibers of the second layer at the interlayer joint are melted, and a part of the melted constituent resin enters between the constituent fibers of the first layer and is solidified. The laminated non-woven fabric is arranged with the second surface facing the wearer's skin side. The absorbent article has a waist circumference corresponding to the wearer's waist circumference, and the laminated non-woven fabric is arranged around the waist circumference.

Further, the present invention has a laminated structure in which a plurality of fiber layers are laminated, has a first surface and a second surface located on the opposite side to the first surface, and the second surface is directed toward the skin side of the wearer. It is a sweat-absorbing sheet used for. It has a hydrophilic first layer forming the first surface and a hydrophobic second layer located on the second surface side of the first layer. The first layer is composed of non-heat-fused fibers. The second layer is mainly composed of heat-sealing fibers, which are long fibers. The laminated non-woven fabric partially has an interlayer joint portion which is smaller in thickness than the peripheral portion and in which the layers constituting the laminated structure are joined to each other in a plan view. The portion having the interlayer joint is recessed from the second surface side toward the first surface side. The constituent fibers of the first layer at the interlayer joint maintain the fiber morphology. The constituent fibers of the second layer at the interlayer joint are melted, and a part of the melted constituent resin enters between the constituent fibers of the first layer and is solidified. The sweat absorbing sheet can absorb sweat.

FIG. 1 is a cross-sectional view schematically showing a cross section along the thickness direction of one embodiment of the laminated nonwoven fabric according to the present invention. FIG. 2 is an enlarged view of an interlayer joint portion in the laminated nonwoven fabric shown in FIG. 3 (a) to 3 (d) are diagrams schematically showing the pattern of the interlayer joint according to the present invention, respectively. FIG. 4 is a schematic view of an embodiment of the method for producing a laminated nonwoven fabric according to the present invention. FIG. 5 is a schematic perspective view of a pants-type disposable diaper according to an embodiment of the absorbent article of the present invention. FIG. 6 is a developed plan view schematically showing the skin contact surface side (inner surface side) of the diaper shown in FIG. 5 in the expanded and extended state. FIG. 7 is a vertical cross-sectional view schematically showing the cross section taken along line II of FIG.

Detailed description of the invention

As described in Patent Documents 1 and 2, it is difficult to reduce the basis weight of each layer constituting the laminated structure of a laminated non-woven fabric in which a plurality of non-woven fabrics are laminated and integrated by thermal embossing, and in particular. It is difficult to reduce the basis weight of the hydrophobic layer. Therefore, such a laminated non-woven fabric has a high basis weight and high rigidity as a whole, and may cause a decrease in wearing feeling when used as a constituent member of an absorbent article, and a hydrophobic layer is formed. When it is placed closest to the wearer's skin, it is inferior in absorption performance of body fluids such as sweat and urine.

Further, as a method for manufacturing a laminated non-woven fabric, fibers are sequentially hung and deposited from a plurality of spinning heads intermittently arranged in the machine direction (MD), and are located downstream of the spinning head located at the most downstream side of the MD. , A method is known in which the deposits of these fibers are heat-embossed and integrated. Such a laminated non-woven fabric produced by so-called direct spinning has a relatively low basis weight and low rigidity. Therefore, when the hydrophobic layer is placed closest to the wearer's skin, the embossed portion in the hydrophobic layer is formed. The body fluid can be absorbed from the periphery of the embossed portion, but the constituent fibers of the hydrophilic layer adjacent to the hydrophobic layer are densely present around the embossed portion, and the thickness of the hydrophobic layer is relatively large. Since it is thin, body fluid easily collects around the embossed portion and easily returns.

Therefore, an object of the present invention is to provide an absorbent article and a sweat-absorbing sheet which are less likely to cause liquid return and have excellent absorption performance of body fluids such as sweat and urine.

Hereinafter, the present invention will be described based on the preferred embodiment with reference to the drawings. FIG. 1 schematically shows a cross section of the laminated nonwoven fabric 10 which is an embodiment of the laminated nonwoven fabric used for the absorbent article of the present invention along the thickness direction Z. The laminated non-woven fabric 10 has a laminated structure 13 in which a plurality of fiber layers are laminated, and the fiber layer is typically a non-woven fabric, that is, a single-layer non-woven fabric (for example, spunbonded non-woven fabric) or a laminated non-woven fabric (for example, SMS non-woven fabric). Each layer that constitutes. The laminated structure 13 has a first surface 10a, which is one surface of the laminated nonwoven fabric 10, and a second surface 10b, which is the other surface of the laminated nonwoven fabric 10 and is located on the opposite side of the first surface 10a.

One of the main features of the laminated non-woven fabric 10 is that the laminated structure 13 has a hydrophilicity gradient in the thickness direction Z. That is, in the laminated structure 13, the first surface 10a is composed of the hydrophilic first layer 11 containing hydrophilic fibers, and the second surface 10b side of the first layer 11 is hydrophobic including hydrophobic fibers. The second layer 12 is arranged, and due to such a configuration, the laminated structure 13 is provided with a hydrophilicity gradient that "the first surface 10a side has a relatively higher hydrophilicity than the second surface 10b side". There is.
Further, the fibers constituting the first layer 11 are also referred to as the first fiber 14, and the fibers constituting the second layer 12 are also referred to as the second fiber 15.

In the laminated non-woven fabric 10 shown in FIG. 1, the laminated structure 13 has a two-layer structure of a hydrophilic first layer 11 and a hydrophobic second layer 12, and the first surface 10a is formed from the first layer 11. The second surface 10b is formed from the second layer 12 and is hydrophobic. Here, "the number of layers of the laminated structure 13 is two layers" means the total number of layers of two layers (first layer 11, second layer 12) having different forms or functions, and is strictly defined. It does not necessarily match the number of layers of the fiber layer (nonwoven fabric) in this sense. That is, as will be described later, the first layer 11 and the second layer 12 can be not only a non-woven fabric having a single-layer structure but also a non-woven fabric having a multi-layer structure of two or more layers (for example, an SMS non-woven fabric), for example, the first layer. When 11 is a non-woven fabric having a single-layer structure and the second layer 12 is an SMS non-woven fabric, even if the laminated structure 13 is a two-layer structure composed of the first layer 11 and the second layer 12, the actual number of layers of the non-woven fabric is , 1 layer in the 1st layer 11 and 3 layers in the 2nd layer 12, for a total of 4 layers. The point is that the first layer 11 and the second layer 12 can be two or more layers, respectively.

In the present invention, the hydrophilicity of the fiber layer (nonwoven fabric), which is an aggregate of fibers, is determined based on the contact angle with water measured by the following method, and if the contact angle is less than 90 degrees, the hydrophilicity is 90. If it is above the degree, it is hydrophobic. The smaller the contact angle with water measured by the following method, the higher the hydrophilicity (lower hydrophobicity), and the larger the contact angle, the lower the hydrophilicity (higher hydrophobicity). In the laminated structure 13 of the laminated non-woven fabric 10, the hydrophilic first layer 11 has a contact angle of less than 90 degrees measured by the following method, and the hydrophobic second layer 12 has a contact angle measured by the following method. Is 90 degrees or more.

<Measurement method of contact angle of fiber layer>
A quadrangular shape in a plan view of 150 mm in the MD direction and 70 mm in the CD direction is cut out from the fiber layer to be measured and used as a measurement sample. Is recorded, and the contact angle is measured based on the recorded image. More specifically, a microscope VHX-1000 manufactured by KEYENCE CORPORATION is used as a measuring device, and a medium-magnification zoom lens is attached to the microscope in a state of being tilted at 90 °. The measurement sample is set on the measurement stage of the measurement device so that the surface to be measured faces upward and can be observed from the CD direction of the measurement sample. Then, a droplet of 3 μL of ion-exchanged water is attached to the surface to be measured of the measurement sample set on the measurement stage, and an image of the droplet is recorded and incorporated into the measurement device. From the plurality of recorded images, 10 images in which both ends or one end in the CD direction of the droplet are clear are selected, the contact angle of the droplet is measured for each of the 10 images, and the average value of the contact angles thereof is measured. Is the contact angle of the fiber layer to be measured. The measurement environment is 20 ° C./50% RH.

The first layer 11 is mainly composed of hydrophilic fibers, and is therefore a hydrophilic layer. Further, it is preferable that the second layer 12 is mainly composed of hydrophobic fibers and is therefore a hydrophobic layer. The first layer 11 contains at least 50% by mass of hydrophilic fibers, and the content of the hydrophilic fibers may be 100% by mass with respect to the total mass of the first layer 11. Further, the second layer 12 is mainly composed of hydrophobic fibers, contains at least 90% by mass or more of hydrophobic fibers, and the content of the hydrophobic fibers is 100% by mass with respect to the total mass of the second layer 12. % May be acceptable.

In the present invention, the hydrophilic fiber has a contact angle of less than 90 degrees measured by the following method, and the hydrophobic fiber has the contact angle of 90 degrees or more. The hydrophilicity of the fiber is determined based on the contact angle with water measured by the following method, and if the contact angle is less than 90 degrees, it is hydrophilic, and if it is 90 degrees or more, it is hydrophobic. The smaller the value of the contact angle measured by the following method, the higher the hydrophilicity (lower hydrophobicity), and the larger the value, the lower the hydrophilicity (higher hydrophobicity).

<Measurement method of fiber contact angle>
The fibers are taken out from the first layer or the second layer of the laminated non-woven fabric using scissors and tweezers, and the fibers are measured. Five fibers of the first layer and five fibers of the second layer are taken out, and the contact angle of the fibers is measured.
As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Deionized water is used to measure the contact angle. The amount of liquid discharged from the inkjet type water droplet discharge unit (Pulse injector CTC-25 manufactured by Cluster Technology Co., Ltd., having a discharge unit hole diameter of 25 μm) is set to 15 picolitres, and water droplets are dropped directly above the fibers. The state of dripping is recorded on a high-speed recording device connected to a horizontally installed camera. From the viewpoint of image analysis later, the recording device is preferably a personal computer incorporating a high-speed capture device. In this measurement, an image is recorded every 17 msec. In the recorded video, the first image of water droplets on the fibers is the attached software FAMAS (software version is 2.6.2, analysis method is droplet method, analysis method is θ / 2, image processing algorithm. Is non-reflective, image processing image mode is frame, threshold level is 200, curvature correction is not performed), the angle between the surface of the water droplet that comes into contact with the air and the fiber is calculated, and the contact is made. Make a corner. The fiber taken out from the object to be measured is cut to a fiber length of 1 mm, and the fiber is placed on a sample table of a contact angle meter and maintained horizontally. Measure the contact angles at two different points for each fiber. By such a method, the contact angle of the five fibers taken out is measured to one digit after the decimal point, and the average value of the measured values at a total of 10 points (rounded to the second digit after the decimal point) is combined with the water of the fiber. Is defined as the contact angle of. The measurement environment is room temperature 22 ± 2 ° C. and humidity 65 ± 2% RH. The smaller the value of the contact angle, the higher the hydrophilicity.

When a measurement sample (for example, a fiber) is contained in a component (for example, a surface sheet or a sweat-absorbing sheet) of an absorbent article, as a method of collecting the measurement sample, the component including the measurement sample is an adhesive. If it is fixed to another component by fusion or the like, it is necessary to release the fixation and take out the component containing the measurement sample from the absorbent article, but the component containing the measurement sample is another. If it is not fixed to the constituent members of the above, a method of collecting the measurement sample directly from the absorbent article can be adopted. Further, as a method of releasing the fixation of the above-mentioned constituent members, in an absorbent article, an adhesive or the like used for joining the constituent member to be measured and another constituent member is weakened by a cooling means such as a cold spray. After that, a method of carefully peeling off the constituent member to be measured and taking it out is preferable. This extraction method is applied in the measurement according to the measurement object of the present invention, such as the measurement of the interfiber distance and the fineness described later. From the viewpoint of minimizing the influence on the hydrophilic agent applied to the constituent members, as a method for removing the fixed portion, there is a risk of causing deterioration or loss of the oil agent such as application of a solvent or hot air blowing with a dryer. It is preferable not to adopt a method with.

The first layer 11 is composed of non-heat-sealing fibers. The first layer 11 is preferably composed mainly of non-heat-sealing fibers. Further, as described above, since the first layer 11 is a hydrophilic layer, it is preferable that the first layer 11 is mainly composed of hydrophilic non-heat-sealing fibers. "Mainly composed of hydrophilic non-heat-fused fibers" means that the fibers contain more hydrophilic non-heat-fused fibers than other fibers. For example, the first layer 11 preferably contains 50% by mass or more of the hydrophilic non-heat-sealing fibers with respect to the total mass of the first layer 11. Further, the content of the hydrophilic non-heat-sealing fiber in the first layer 11 may be 100% by mass with respect to the total mass of the first layer 11.
As the hydrophilic non-heat-sealing fiber, a natural fiber, a regenerated cellulose fiber, a semi-synthetic fiber or the like can be used. Examples of the natural fiber include cotton fiber, silk fiber, pulp fiber, lyocell fiber which is a purified cellulose fiber, and the like. 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.
These hydrophilic non-heat-sealing fibers may be used alone or in combination of two or more.

Further, the first layer 11 may contain heat-sealing hydrophilic fibers in addition to the above-mentioned hydrophilic non-heat-sealing fibers. The heat-sealing hydrophilic fibers include fibers that have been hydrophilized so that the contact angle is less than 90 degrees. Examples of such fibers include fibers in which a hydrophilic agent is kneaded, fibers in which a hydrophilic agent is attached to the surface, and fibers subjected to plasma treatment. The hydrophilic agent is not particularly limited as long as it is a general hydrophilic agent used for hygienic products.
Further, the hydrophobic fiber includes a fiber whose contact angle is 90 degrees or more after being hydrophobized. Examples of such fibers include long fibers kneaded with a hydrophobizing agent, fibers having a hydrophobizing agent attached to the surface, and fibers subjected to plasma treatment. The hydrophobizing agent is not particularly limited as long as it is a general hydrophobizing agent used for hygienic products.

The first layer 11 is preferably a non-woven fabric composed of the above-mentioned fibers contained in the first layer 11, and more preferably a non-woven fabric mainly composed of the above-mentioned non-heat-sealing fibers. The non-heat-fused fiber is preferably a short fiber. That is, it is preferable that the first layer 11 is a non-woven fabric mainly composed of non-heat-fused short fibers, that is, a non-heat-fused short fiber non-woven fabric. Examples of such non-woven fabrics include spunlace non-woven fabrics, needle punch non-woven fabrics, chemical bond non-woven fabrics and the like.
In the present invention, the "short fiber" means a fiber having a fiber length of 70 mm or less, preferably 64 mm or less.
In the present invention, the "fiber length" refers to the average fiber length and is measured by the following method.

<Measurement of average fiber length>
The fiber length of the fibers constituting the first layer or the second layer of the laminated non-woven fabric is measured by the average fiber length measuring method (C method) of JIS L1015. When the short fiber is pulp, it is measured according to JIS P8226 (Pulp-Fiber length measurement method by optical automatic analysis method) (2006), and the average fiber length is obtained.

The second layer 12 is mainly composed of long fibers. The definition of long fibers will be described later.
The second layer 12 is mainly composed of heat-sealing fibers. Here, "mainly the heat-fusing fiber" means that the heat-fusing fiber is contained in a larger amount than the non-heat-fusing fiber. The above-mentioned hydrophobic fibers are heat-sealing fibers.
As a material for heat-sealing fibers of long fibers, for example, polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyacrylic acid, polymethacrylic acid alkyl ester, polyvinyl chloride, poly Examples thereof include resin fibers such as vinylidene chloride, and one of these fibers can be used alone or in combination of two or more.

The fibers used as the constituent fibers of the second layer 12 may be single fibers made of one kind of synthetic resin or a blend polymer obtained by mixing two or more kinds of synthetic resins, or may be composite fibers. The composite fiber referred to here is a synthetic fiber obtained by combining two or more kinds of synthetic resins having different components with a spinneret and spinning them at the same time, and is a single fiber having a structure in which a plurality of components are continuous in the length direction of the fiber. Those that are mutually bonded within. The form of the composite fiber includes a core sheath type, a side-by-side type, and the like, and is not particularly limited.

In the present invention, the "long fiber" means a fiber having a fiber length of 75 mm or more, preferably 100 mm or more. In particular, a so-called continuous long fiber having a fiber length of 150 mm or more is more preferable in that a long fiber non-woven fabric having high breaking strength can be obtained. The upper limit of the fiber length in the "long fiber" is not particularly limited. Further, the "long-fiber non-woven fabric" typically refers to a non-woven fabric having a fiber aggregate in which long fibers are intermittently fixed by a heat-sealing portion. Examples of such long-fiber non-woven fabrics include single-layer non-woven fabrics such as spunbonded non-woven fabrics and melt-blown non-woven fabrics, laminated non-woven fabrics in which spunbond layers mainly composed of long fibers and melt-blown layers are laminated, and heat-rolled non-woven fabrics produced by the card method. Examples of the laminated non-woven fabric include spunbond-spunbond laminated non-woven fabric (SS non-woven fabric), spunbond-spunbond-spunbond laminated non-woven fabric (SSS non-woven fabric), and spunbond-melt blown-spunbond laminated non-woven fabric (SMS). Non-woven fabric), spunbond-melt blown-melt blown-spunbond non-woven fabric (SMMS non-woven fabric) and the like. In general, long-fiber non-woven fabrics are superior in strength to short-fiber non-woven fabrics.

As shown in FIG. 1, the laminated nonwoven fabric 10 has a thickness smaller than that of the peripheral portion, and partially has an interlayer joining portion 16 in which the layers constituting the laminated structure 13 are joined to each other in a plan view of the laminated nonwoven fabric 10. ing. In the interlayer joint 16, a part of the constituent fibers (second fiber 15) of the second layer 12 constituting the laminated structure 13 is melted and heat-sealed to the first layer 11 to cause the first layer 11 to be fused. And the second layer 12 are joined.

In the laminated non-woven fabric 10, the interlayer bonding portion 16 is a laminate of a precursor of the laminated structure 13 (a laminate of a first layer 11 as a base sheet and a deposit of a second fiber 15) from the second surface 10b side to the first surface. It is formed by pressing it toward the 10a side, and due to such a forming method, as shown in FIGS. 1 and 2, the portion having the interlayer joint 16 is formed from the second surface 10b side to the first surface 10a. It is recessed toward the side. That is, the interlayer joining portion 16 exists at the bottom of the recess 17 formed by pressing such as embossing, which will be described later, and joins the first layer 11 and the second layer 12. In the recess 17 formed by pressing, the constituent fibers of the first layer 11 and the second layer 12 are made denser than the peripheral portion thereof. In the laminated non-woven fabric 10, a plurality of interlayer bonding portions 16 are scattered on each of the first surface 10a and the second surface 10b. In the embodiment shown in FIG. 1, the laminated nonwoven fabric 10 is a flat surface having substantially no irregularities on the first surface 10a and an uneven surface having irregularities on the second surface 10b. Further, the interlayer joint portion 16 is formed in the same pattern in the plan view of both the first surface 10a and the second surface 10b.

The recess 17, that is, the portion having the interlayer joint portion 16 is a portion in which the constituent fibers of the portion are compacted in the thickness direction, and this consolidation is typically heat fusion such as heat and ultrasonic waves. It is carried out by embossing with a melting promoting means for promoting melting of the adhesive fiber, specifically, for example, heat sealing, ultrasonic sealing or the like. Focusing on the manufacturing method in this way, the portions having the interlayer joint portions 16 can also be referred to as embossed portions or pressed portions, respectively.

As shown in FIG. 1, the first layer 11 constituting the laminated structure 13 in the present embodiment has only the interlayer joint portion 16. The first layer 11 has, in addition to the interlayer joining portion 16, a consolidation portion (not shown) in which the thickness is smaller than that of the peripheral portion and the constituent fibers of the first layer 11 are densified from each other. You may. The consolidation portion is formed in the first layer in a pattern different from that of the interlayer joint portion 16, and has a higher density than the peripheral portion.
This compacted portion presses the precursor of the first layer 11 (the web that is the deposit of the first fiber 14) from the first surface 10a side to the second surface 10b side, or from the second surface 10b side to the first surface 10a side. It can be formed by doing. Due to such a forming method, the consolidated portion has a concave shape from the first surface 10a side to the second surface 10b side, or from the second surface 10b side to the first surface 10a side. Further, a plurality of compacted portions are scattered on the first surface 10a. As described above, in the laminated nonwoven fabric 10, the first surface 10a may have a compacted portion, and the first surface 10a may be an uneven surface due to this.

When one or both of the first surface 10a and the second surface 10b of the laminated nonwoven fabric 10 has irregularities, for example, a component (for example, a sweat absorbing sheet) capable of contacting the laminated nonwoven fabric 10 with the wearer's skin in an absorbent article. ), By arranging the laminated non-woven fabric 10 so that the uneven surface is in contact with the wearer's skin, a space is formed between the laminated non-woven fabric 10 and the wearer's skin, and excreted sweat or sweat or the like. Since the moisture generated from the body fluid such as urine can be effectively dissipated through the space, the surface dry feeling of the laminated non-woven fabric 10 can be improved, which can lead to the improvement of the wearing feeling of the absorbent article.

In the laminated non-woven fabric 10, since the second surface 10b is hydrophobic and the second layer 12 forming the second layer 12 contains hydrophobic fibers, it is basically difficult to absorb body fluids (aqueous liquids) such as sweat and urine. However, regarding the interlayer joint 16 and its surroundings on the second surface 10b, not only the hydrophobic fibers but also the hydrophilic fibers of the first layer 11 which is adjacent to the second layer 12 and has a higher hydrophilicity. Are relatively densely present, so that the hydrophilicity is high (the contact angle measured by the above method is small) as compared with other parts on the second surface 10b, and therefore, the layers are formed on the second surface 10b. Body fluids may preferentially adhere to the junction 16 and its surroundings. As described above, since the laminated structure 13 has a hydrophilicity gradient that "the first surface 10a side has a relatively higher hydrophilicity than the second surface 10b side" in the thickness direction Z, the second surface 10b The body fluid adhering to the interlayer bonding portion 16 and its surroundings is likely to be drawn into the laminated non-woven fabric 10 mainly through the peripheral edge of the interlayer bonding portion 16 and its vicinity. The peripheral edge of the interlayer joint portion 16 is a boundary portion between a portion where the constituent fibers (second fiber 15) of the second layer 12 are melted and a portion where the constituent fibers (second fiber 15) of the second layer 12 are not melted by pressing such as embossing, and the interlayer joint portion 16 The vicinity of the recess 17 is a portion other than the interlayer joint 16 in the recess 17, and the constituent fibers (second fiber 15) of the second layer 12 surrounding the interlayer joint 16 in the recess 17 maintain the fiber morphology. This is the part with high density.

The contact angle of the constituent fibers (hydrophobic fibers) of the second layer 12 is higher than that of the constituent fibers (hydrophilic fibers) of the first layer 11 from the viewpoint of more reliably achieving the effect of liquid absorption due to the hydrophilicity gradient. It is preferably 95 degrees or more, more preferably 100 degrees or more, and preferably 150 degrees or less, still more preferably 130 degrees or less, on the premise that the temperature is large. Further, on the premise that the contact angle of the constituent fibers (hydrophilic fibers) of the first layer 11 is smaller than that of the constituent fibers (hydrophobic fibers) of the second layer 12, it is preferably 5 degrees or more, more preferably. It is 10 degrees or more, preferably 88 degrees or less, and more preferably 85 degrees or less. The hydrophilicity of the constituent fibers can be adjusted by, for example, appropriately adjusting the type and content of the hydrophilic agent.

Further, from the viewpoint of improving the effect of liquid absorption due to the hydrophilicity gradient, the first layer 11 has a relatively low hydrophilicity on the first surface 10a side and a relatively high hydrophilicity on the second surface 10b side. Is preferable. With such a configuration, the body fluid drawn into the laminated nonwoven fabric 10 is diffused in the plane direction of the laminated nonwoven fabric 10 (the direction orthogonal to the thickness direction Z), and the first hydrophilic surface is inside the thickness direction Z. It can be absorbed and retained in the layer 11.

The interlayer joint portion 16 is a joint portion in which the constituent fibers of the second layer 12 are melted and fused to the first layer 11, but the constituent fibers of the first layer 11 in the interlayer joint portion 16 are shown in FIGS. 1 and 2. As shown in, the fiber morphology is maintained. On the other hand, the constituent fibers of the second layer 12 in the interlayer joint 16 are the constituent resins 15a that have lost their fiber morphology due to melting by heating such as embossing. As shown in FIG. 2, a part of the molten constituent resin 15a penetrates between the constituent fibers of the first layer and solidifies. The first layer 11 of the laminated nonwoven fabric 10 of the present embodiment has a portion in which the constituent resin 15a in which the second fiber 15 is melted has entered and a portion in which the constituent resin 15a in which the second fiber 15 has melted has not entered, in a portion overlapping the interlayer bonding portion 16 in the thickness direction Z. ing. The first layer 11 of the laminated nonwoven fabric 10 may contain the constituent resin 15a in the entire area overlapping the interlayer joint portion 16 in the thickness direction Z, but as in the present embodiment, the second fiber 15 is melted. It is preferable that there is a portion in which the resin 15a does not enter.
In the interlayer joint 16, the constituent fibers of the second layer 12 may be partially melted.

As described above, the interlayer joint portion 16 in the recess 17 has a higher density of fiber resin than the periphery of the recess 17, so that liquid such as sweat easily adheres to the interlayer joint portion 16 and from the peripheral edge of the interlayer joint portion 16. In the vicinity thereof, the fiber morphology of the constituent fibers (second fiber 15) of the second layer is maintained as compared with the interlayer joint portion 16, so that the liquid is applied to the plurality of second fibers 15 in which the fiber morphology is maintained. By adhering, the liquid easily enters between the second fibers 15. That is, the liquid that has entered the recess 17 is likely to be drawn into the first surface 10a side from the peripheral edge of the interlayer joint 16 in the recess 17 and its vicinity. In this way, the peripheral edge of the interlayer joint 16 in the recess 17 and its vicinity serve as a liquid drawing portion.
Further, in the interlayer joint 16, the constituent fibers of the first layer 11 maintain the fiber morphology, and a part of the constituent fibers of the second layer is melted between the constituent fibers of the first layer 11. Since the resin 15a is contained, the liquid is transferred to the second surface of the interlayer joint portion 16 by allowing the first fiber 14 of the first layer to coexist between the second fibers 15 of the second layer. It is easy to pull in from the 10b side to the first surface 10a side.
Further, since the second layer is mainly composed of long fibers, the second fibers 15 are oriented in the plane direction of the laminated non-woven fabric, and the thickness is small and the thickness is further reduced by the formation of the interlayer joint portion 16. It is easy to do so, and the liquid that has entered the peripheral edge of the interlayer joint 16 and its vicinity easily comes into contact with the hydrophilic first fibers 14 of the first layer 11, so that the liquid on the second surface 10b side is easily absorbed.
As described above, the laminated non-woven fabric 10 includes the above-mentioned hydrophilicity gradient, the peripheral edge of the interlayer bonding portion 16 acting as a liquid drawing portion and its vicinity, and the second fiber 15 which is a hydrophobic constituent fiber of the second layer 12. It is excellent because it has a portion where the first fiber 14 which is the hydrophilic constituent fiber 14 of the first layer 11 coexists and a thin portion of the second layer 12 where the distance to the first layer 11 is small. Has absorption performance.

When the first layer 11 is composed of the short fibers, the short fibers are oriented not only in the plane direction but also in the thickness direction of the laminated nonwoven fabric, so that the hydrophilic first fiber 14 is the second layer 12 The effect of easily entering between the hydrophobic second fibers 15 oriented in the plane direction of the above is achieved.

As described above, the first layer 11 of the laminated non-woven fabric 10 of the present embodiment penetrates into the portion where the constituent resin 15a in which the second fiber 15 is melted has entered in the portion overlapping the interlayer joint portion 16 in the thickness direction Z. It has a non-woven fabric (see FIGS. 1 and 2). With such a configuration, the fibers on the second surface 10b side of the first layer 11 are fixed between the fibers by the molten second fiber 15 in the portion other than the interlayer joint portion 16 in the plane direction of the laminated nonwoven fabric. The density is higher than that of the fibers on the 10a side of one surface. On the other hand, on the first surface 10a side of the first layer 11, the first fibers 14 are not fixed in the thickness direction and the interfiber distance is large. As a result, even in the first layer 11, a coarse and dense gradient of fibers is generated on the first surface 10a side and the second surface 10b side, and the effect that the liquid is retained inside the laminated non-woven fabric 10 is exhibited.

The peripheral edge of the interlayer joint 16 and its vicinity in the recess 17 are important parts that serve as a liquid drawing portion when the liquid is absorbed from the hydrophobic second surface 10b, but the hydrophobic first surface 16 is formed. When the laminated nonwoven fabric 10 is compressed in the thickness direction after absorbing liquid due to the bonding between the two layers 12 and the hydrophilic first layer 11 (for example, the laminated nonwoven fabric 10 wears the second surface 10b). When used as a constituent member of an absorbent article toward the skin side of a person (when the wearer's body pressure is applied to the laminated non-woven fabric 10), one of the constituent fibers of the second layer 12 at the interlayer joint 16 Since the portion becomes the constituent resin 15a in which the fiber morphology of the heat-sealing fiber is lost and melted, it is effective to return the liquid to the second surface 10b side via the constituent resin 15a, that is, the interlayer bonding portion 16. Is suppressed. Therefore, when the laminated non-woven fabric 10 is used as a member that comes into contact with the skin of the wearer of the absorbent article, a good touch such as non-stickiness can be obtained even after the laminated non-woven fabric 10 absorbs a body fluid such as sweat.
The fiber morphology of the constituent fibers in the interlayer bonding portion 16 mainly depends on the embossing conditions when forming the interlayer bonding portion 16, and when the heating and pressurizing conditions during the embossing processing are relatively weak, the fibers of the constituent fibers are used. The morphology is easier to maintain.

The second layer 12 of the present embodiment partially has a melt-bonded portion in which heat-sealing fibers are bonded to each other in a plan view of the laminated non-woven fabric. The melt-bonded portion is a portion where the constituent fibers of the second layer 12 are melt-solidified. From the viewpoint of improving the drawing of the liquid, it is preferable that the melt joint portion constitutes the second layer portion of the interlayer joint portion 16. That is, it is preferable that the melt-bonded portion constitutes a portion of the second layer 12 of the interlayer-bonded portion 16 in the thickness direction of the laminated non-woven fabric, that is, a portion in which the constituent fibers of the second layer of the interlayer-bonded portion 16 are melted. In this case, the constituent fibers (second fibers) melted at the melt-bonded portion enter between the constituent fibers of the first layer that maintain the fiber morphology and are solidified. Further, it is preferable that more than half of the melt joints form the second layer portion of the interlayer joint 16, and all of the melt joints form the second layer portion of the interlayer joint 16. Is more preferable.

The interlayer joint 16 is partially formed in the plan view of the laminated nonwoven fabric 10, but the formation pattern thereof is not particularly limited. FIG. 3 illustrates the pattern (planological shape and arrangement) of the interlayer joint portion 16. The pattern of the interlayer joint 16 on the first surface 10a or the second surface 10b is not limited to that shown in FIG. 3, and a desired pattern can be adopted without departing from the spirit of the present invention.
3 (a) to 3 (c) are patterns in which a plurality of interlayer joints 16 having a predetermined shape in a plan view are scattered in the plane direction (direction orthogonal to the thickness direction of the laminated non-woven fabric 10). The plan-view shape of the interlayer joint 16 is an elliptical shape (oblong shape) in FIG. 3A, a circular shape in FIG. 3B, and a quadrangular or rhombic shape in FIG. 3C. Further, FIG. 3D shows a pattern in which the interlayer joints 16 having a plane line of sight are arranged so as to extend in a predetermined direction, and more specifically, a plurality of continuous linear interlayer joints 16 intersect with each other. The interlayer joint 16 as a whole has a grid pattern.

As described above, since the peripheral edge of the interlayer joint 16 and its vicinity are sites that become a liquid drawing portion when the liquid is absorbed from the second surface 10b, from the viewpoint of improving the liquid absorption of the laminated non-woven fabric 10. It is preferable that the second surface 10b has an interlayer joint dispersed arrangement region in which a plurality of interlayer joints 16 are scattered in the plane direction. In particular, when the laminated non-woven fabric 10 is used as a sweat absorbing sheet capable of absorbing sweat, if the second surface 10b has the interlayer joint dispersed arrangement region, the sweat absorption can be further improved. preferable. The entire area of the second surface 10b may be the interlayer joint distributed arrangement region, or only a part of the second surface 10b may be the interlayer joint distributed arrangement region. The ratio of the area of the interlayer joint distributed arrangement region to the total area of the second surface 10b is preferably 70% or more, more preferably 80% or more.

Further, regarding the arrangement of the interlayer joint portion 16 in the interlayer joint portion distributed arrangement region, when a circle having a radius of 2 mm is virtually provided at an arbitrary position of the interlayer joint portion distributed arrangement region on the second surface 10b, the virtual circle is provided. It is preferable that a part or all of at least one interlayer joint 16 is included therein. Here, the meaning of "when a circle having a radius of 2 mm is virtually provided at an arbitrary position, a part or all of at least one interlayer joint 16 is included in the virtual circle" means "second When 10 virtual circles are provided in the interlayer joint distributed arrangement region on the surface 10b, the interlayer joint 16 may not be included at all in one or two of the ten virtual circles. , The remaining eight virtual circles need only include a part or all of at least one interlayer joint 16. " The virtual circle assumes sweat secretion points (sweat glands) scattered on the skin surface of the human body, and the laminated non-woven fabric 10 can absorb sweat more efficiently by having the above-mentioned structure. In particular, when the radius of the virtual circle is 1.5 mm, it is more effective if the interlayer joint 16 is arranged so as to satisfy the above.

Since the portion having the interlayer joint 16 is a liquid drawing portion on the second surface 10b, a certain number of interlayer joints 16 is required from the viewpoint of ensuring sufficient liquid absorption for practical use, that is, between layers. It is necessary that the peripheral length of the joint portion 16 has a certain length or more. On the other hand, it is not preferable that the area of the interlayer bonding portion 16 itself is too large, and if the interlayer bonding portion 16 is excessively present on the second surface 10b, the interlayer bonding portion 16 is hydrophilic as well as the hydrophobic second layer 12. Since the first layer 11 of the above is also fused together, the amount of liquid that the first layer 11 can absorb and hold may decrease. From such a viewpoint, the total area of the interlayer joint 16 with respect to the area of the second surface 10b (when a plurality of interlayer joints 16 are formed on the second surface 10b, the total area of the plurality of interlayer joints 16). The ratio, that is, the area ratio of the interlayer joint portion 16 is preferably 15% or less, more preferably 12% or less. The lower limit of such a ratio is preferably 5% or more, more preferably 6% or more.

The interlayer joint portion 16 is continuous over the entire thickness direction Z of the laminated structure 13 (laminated non-woven fabric 10), and the pattern (planar view shape) of the interlayer joint portion 16 is formed by the first surface 10a and the second surface 10b in a plan view. And arrangement) are substantially the same. Therefore, the description regarding the pattern of the interlayer joint 16 with respect to the second surface 10b in the present specification (the interlayer joint distributed arrangement region, the area ratio of the interlayer joint 16 and the like) is described. Unless otherwise specified, it also applies to the first surface 10a.

Similarly, from the viewpoint of achieving both liquid absorption and liquid return prevention, the area of one interlayer joint 16 on the second surface 10b is preferably 1 mm ² or less, more preferably 0.8 mm ² or less. Yes, and the lower limit is preferably 0.1 mm ² or more, more preferably 0.15 mm ² or more.

The basis weight of the first layer 11 and the second layer 12 is not particularly limited, and may be appropriately adjusted according to the use of the laminated non-woven fabric 10. For example, when the laminated non-woven fabric 10 is used as a constituent member (surface sheet, sweat-absorbing sheet, etc.) of an absorbent article such as a disposable diaper or a sanitary napkin, the viewpoint is to ensure sufficient strength for practical use and not to be bulky. Therefore, the combined basis weight of the first layer 11 and the second layer 12 is preferably 11 g / m ² or more, more preferably 14 g / m ² or more, and preferably 55 g / m ² or less, further preferably 50 g / m. It is m ² or less.

In particular, when the first layer 11 diffuses and retains the liquid absorbed through the hydrophobic second layer 12 (second surface 10b), the basis weight of the first layer 11 is related to the absorption capacity of the liquid. In general, the larger the basis weight of the first layer 11, the higher the absorption capacity and the higher the strength. On the other hand, if the basis weight of the first layer 11 is too large, it becomes bulky or the rigidity is increased, and as a result, when it is used as a constituent member of an absorbent article, the wearing feeling may be deteriorated. Considering the above, the basis weight of the first layer 11 is preferably 8 g / m ² or more, more preferably 11 g / m ² or more, and preferably 40 g / m ² or less, still more preferably 35 g / m ² or less. is there.

Further, the hydrophobic second layer 12 is usually the side that first comes into contact with the liquid when the laminated non-woven fabric 10 is used for liquid absorption, but in such a usage mode, the second layer 12 is The smaller the basis weight and the thinner the thickness, the easier it is to absorb the liquid through the peripheral edge of the interlayer joint 16 on the second surface 10b and its vicinity. On the other hand, the basis weight of the second layer 12 is required to be more than a certain amount from the viewpoint of strength reduction and liquid return. Considering the above, the basis weight of the second layer 12 is preferably 3 g / m ² or more, more preferably 5 g / m ² or more, and preferably 25 g / m ² or less, more preferably 15 g / m ² or less. More preferably, it is 13 g / m ² or less. Normally, from the viewpoint of the strength of the second layer 12, a certain basis weight or more is required for manufacturing the laminated nonwoven fabric 10, but according to the manufacturing method described later for the laminated nonwoven fabric, the second layer 12 is so-called direct spinning. Since it is manufactured by the method, it can be manufactured without any problem even with a low basis weight of about 3 g / m ² .

As described above, various non-woven fabrics can be used as the first layer 11 and the second layer 12, but when the laminated non-woven fabric 10 is used as a constituent member of an absorbent article, for example, when it is used for liquid absorption. From the viewpoint of ensuring that the above-mentioned effects are more reliably achieved, the hydrophilic first layer 11 includes heat-sealing fibers made of a resin coated or kneaded with a hydrophilic agent. Air-through non-woven fabrics, heat-roll non-woven fabrics, and spunlace non-woven fabrics in which hydrophilic non-heat-sealed fibers are mixed or laminated are particularly preferable.

Further, as a preferable other example of the hydrophilic first layer 11, an air-through non-woven fabric or a heat roll non-woven fabric containing 70% by mass or more, preferably 75% by mass or more of hydrophilic fibers, and more preferably the above-mentioned compacted portion is the air-through. Examples thereof include those formed on the entire non-woven fabric or spunlaced non-woven fabric. In such an air-through non-woven fabric or a heat roll non-woven fabric, the area of one compacted portion is preferably 0.1 mm ² or more, more preferably 0.15 mm ² or more, and preferably 1 mm ² or less, further preferably 0.8 mm ^2. It is as follows. Further, on one surface of such an air-through non-woven fabric or a heat roll non-woven fabric, the number of compacted portions existing per unit area of 10 mm square is preferably 4 or more, more preferably 6 or more, and preferably 30 or less, further. The number is preferably 28 or less.

On the other hand, as the hydrophobic second layer 12, spunbonded non-woven fabric, melt-blown non-woven fabric, or laminated non-woven fabric thereof (for example, SMS non-woven fabric) is preferable because the thickness is relatively small and therefore the liquid is relatively easily absorbed.

The hydrophilic fiber contained in the first layer 11 may be obtained by subjecting the raw material fiber to a hydrophilic treatment. That is, the first layer 11 can include an aggregate of raw material fibers (for example, heat-sealing fibers) that has been hydrophilized. As the hydrophilization treatment, as described above, coating of a hydrophilic agent on the fiber or the fiber aggregate, kneading of the hydrophilic agent on the fiber, plasma treatment, etc. can be used, but the hydrophilic agent can be used. The process to be used is common.

As an example of the first layer 11, a form in which a hydrophilic agent is coated on the second surface 10b side (the hydrophilic agent is attached to the surface of the constituent fibers on the second surface 10b side) can be mentioned. The second surface 10b side of the first layer 11 is opposite to the first surface 10a, and is a layer adjacent to the first layer 11, that is, a layer having a lower hydrophilicity than the first layer 11 (in the form shown in FIG. 1). Is the contact surface side with the hydrophobic second layer 12). In the first layer 11 of such a form, a large amount of hydrophilic agents adhering to the surface of constituent fibers such as non-heat-sealing fibers are unevenly distributed on the second surface 10b side rather than the first surface 10a side. Therefore, the first layer 11 has a hydrophilicity gradient in which the first surface 10a side has a relatively low hydrophilicity and the second surface 10b side has a relatively high hydrophilicity. As described above, when the hydrophilicity of the first layer 11 is higher on the second surface 10b side than on the first surface 10a side, the laminated structure 13 has a hydrophobic second surface that first contacts the liquid to be absorbed. Hydrophileity in which the hydrophilicity gradually increases (the contact angle measured by the above method gradually decreases) from the layer 12 (second surface 10b) toward the inside of the laminated structure 13 in the thickness direction Z. Since a degree gradient is formed, further improvement in liquid absorption can be expected.

The method for applying the hydrophilic agent is not particularly limited, and a known method capable of applying a coating liquid containing the hydrophilic agent can be appropriately used. As the coating method that can be used, gravure coat, kiss coat, flexo coat, spray coat, reverse coat and die coat are preferable, and among them, gravure coat, flexo coat, spray coat and die coat that can be coated with a pattern are particularly preferable. Further, as the hydrophilic agent, various surfactants used for hydrophilizing the constituent members in absorbent articles such as disposable diapers can be used without particular limitation.

As another example of the first layer 11, there is a form in which a hydrophilic treatment agent is attached to the constituent fibers in the spinning step or the drawing step at the time of manufacturing the constituent fibers (first fiber 14). In that case, since each fiber is subjected to a hydrophilic treatment, the hydrophilicity of the obtained non-woven fabric exhibits uniform and stable performance.
On the other hand, in the process of manufacturing webs using a card machine, a plurality of webs made of raw material fibers having different hydrophilicities are laminated and hot air treated, so that the first surface 10a side and the second surface 10b side are formed. The first layer 11 having different hydrophilicity can be produced. In this case, by using a raw material fiber having a higher hydrophilicity on the second surface 10b side of the first layer 11, the first surface 10a side has a relatively low hydrophilicity and the second surface 10b side has a relatively high hydrophilicity. , A non-woven fabric having a hydrophilicity gradient. As described above, when the hydrophilicity of the first layer 11 is higher on the second surface 10b side than on the first surface 10a side, the laminated structure 13 has a hydrophobic second surface that first contacts the liquid to be absorbed. Hydrophileity in which the hydrophilicity gradually increases (the contact angle measured by the above method gradually decreases) from the layer 12 (second surface 10b) toward the inside of the laminated structure 13 in the thickness direction Z. Since a degree gradient is formed, further improvement in liquid absorption can be expected.

Further, when a plurality of webs made of raw material fibers having different hydrophilicity are laminated to prepare a non-woven fabric of the first layer 11 as described above, non-thermal fusion of pulp, cotton, rayon, etc. is performed on the second surface 10b side. By mixing the sex fibers, further improvement in liquid absorption can be expected.
Here, a method for producing the first layer 11 by an air-through method for producing a non-woven fabric by passing hot air through the web has been shown. Can be adopted.

Further, the liquid absorbency of the laminated non-woven fabric 10 is influenced not only by the hydrophilicity gradient in the thickness direction described above but also by the thickness of the hydrophobic second layer 12. In the hydrophobic fiber layer, the small distance between fibers and the large thickness are factors for increasing water resistance. Therefore, when the hydrophobic second layer 12 (second surface 10b) is the layer that first contacts the liquid to be absorbed (the layer that draws in the liquid), in order to improve the liquid absorbency of the laminated non-woven fabric 10. It is preferable that the thickness of the second layer 12 is small and the fiber density is low (the distance between fibers is long). On the other hand, the hydrophilic layer adjacent to this (first layer 11 in the illustrated form) has a high capillary force and can absorb water through the hydrophobic layer, so that the fiber density is high (distance between fibers is high). (Short) is preferable. In the interlayer joint 16 and its surroundings, the first layer has a relatively low fiber density (long interfiber distance) and a high fiber density (short interfiber distance) from between the fibers of the second layer 12 (second surface 10b). The first fiber 14 of the layer 11 is easily exposed to the second surface 10b side. The liquid is rapidly drawn into the inside from the peripheral edge of the interlayer joint 16 on the second surface 10b and its vicinity, and the drawn liquid is absorbed and held in the hydrophilic first layer 11 more stably. .. From such a viewpoint, it is preferable that the first layer 11 has a higher fiber density than the second layer 12, that is, the interfiber distance of the constituent fibers is short. Further, it is preferable that the constituent fibers on the second surface 10b side of the first layer 11 have a smaller inter-fiber distance than the constituent fibers on the first surface 10a side of the first layer 11. The interfiber distance is measured by the following method.

<Measurement method of interfiber distance>
The interfiber distance of a fiber aggregate such as a non-woven fabric or paper is calculated by the following formula (2) based on the assumption of Wrotnowski. The following formula (2) is generally used when determining the interfiber distance of the fiber aggregate. Under Wrotnowski's assumptions, the fibers are columnar and the fibers are regularly arranged without intersecting.
When the sheet to be measured (first layer 11, second layer 12) has a single-layer structure, the interfiber distance of the single-layer structure sheet is calculated by the following formula (2).
When the sheet to be measured (first layer 11, second layer 12) has a multi-layer structure such as an SMS non-woven fabric, the inter-fiber distance in the fiber layer of the multi-layer structure is determined according to the following procedure.
First, the interfiber distance of each fiber layer constituting the multilayer structure is calculated by the following formula (2). At that time, the thickness t, the basis weight W, the resin density ρ of the fiber, and the fiber diameter D used in the following formula (2) are those for the layer to be measured, respectively. The thickness t, the basis weight W, and the fiber diameter D are the average values of the measured values at a plurality of measurement points, respectively.
The thickness t (mm) is measured by the following method. First, the sheet to be measured is cut in a longitudinal direction of 50 mm and a width direction of 50 mm to prepare a cut piece of the sheet. However, when a cut piece of this size cannot be prepared as a sheet to be measured, such as when a sheet is collected from a small absorbent article, a cut piece as large as possible is prepared. Next, this cut piece is placed on a flat plate, a glass plate on the flat plate is placed on the flat plate, and weights are evenly placed on the glass plate so that the load including the glass plate becomes 49 Pa, and then the cutting is performed. Measure the thickness of the piece. The measurement environment is a temperature of 20 ± 2 ° C., a relative humidity of 65 ± 5%, and a scope (manufactured by KEYENCE CORPORATION, VHX-1000) is used as the measuring device. To measure the thickness of the cut piece, first, an enlarged photograph of the cut surface of the cut piece is obtained. In this magnified photograph, the ones of known dimensions are simultaneously projected. Next, the scale is adjusted to the enlarged photograph of the cut surface of the cut piece, and the thickness of the cut piece, that is, the thickness of the sheet to be measured is measured. As the thickness of this sheet, the thickness of the portion other than the interlayer joint 16 is measured. The above operation is performed three times, and the average value of the three times is defined as the thickness t of the sheet to be measured. When the sheet to be measured is a laminated product, the boundary is determined from the fiber diameter and the thickness is calculated.
The basis weight W (g / m ² ) is obtained by cutting a sheet to be measured to a predetermined size (for example, 12 cm × 6 cm), measuring the mass, and then measuring the mass measurement value with an area obtained from the predetermined size. It is obtained by dividing (“Basis weight W (g / m ² ) = mass ÷ area obtained from a predetermined size”). Measure 4 times and use the average value as the basis weight.
The resin density ρ (g / cm ³ ) of the fiber is measured using a density gradient tube according to the measurement method of the density gradient tube method described in JIS L1015 Chemical Fiber Staple Test Method (URL is http: ///). kikakuri.com/l/L1015-2010-01.html, JIS Handbook Fiber-2000 for books, p.764-765 of (Japanese Standards Association).
For the fiber diameter D (μm), 10 fiber cross sections of the cut fibers are measured using an S-4000 type field emission scanning electron microscope manufactured by Hitachi, Ltd., and the average value thereof is taken as the fiber diameter. The method for measuring the fiber diameter D follows the <method for measuring the fiber diameter> described later.
Next, the interfiber distance of each layer is multiplied by the ratio of the thickness of the layer to the total thickness of the multilayer structure, and the numerical values of the obtained layers are totaled to obtain the desired multilayer structure sheet. The interfiber distance of the constituent fibers of is obtained. For example, in an SMS non-woven fabric having a three-layer structure composed of two S layers and one M layer, the two S layers are collectively treated as one layer, and the thickness t of the entire three-layer structure is 0.11 mm. When the thickness t of the S layer is 0.1 mm, the interfiber distance LS of the S layer is 47.8 μm, the thickness t of the M layer is 0.01 mm, and the interfiber distance LS of the M layer is 3.2 μm, such an SMS non-woven fabric The interfiber distance of the constituent fibers of is 43.8 μm [= (47.9 × 0.1 + 3.2 × 0.01) /0.11].

As described above, the interfiber distance L1 of the constituent fibers of the first layer 11 (first fiber 14) <the interfiber distance L2 of the constituent fibers (second fiber 15) of the second layer 12 (L1 <L2). As a premise, the ratio (L2 / L1) of the interfiber distance L2 of the constituent fibers (second fiber 15) of the second layer 12 to the interfiber distance L1 of the constituent fibers of the first layer 11 (first fiber 14) is preferable. Is 1.1 or more, more preferably 10 or more, and preferably 70 or less, still more preferably 50 or less.
The interfiber distance L1 of the constituent fibers (first fiber 14) of the first layer 11 is preferably 5 μm or more, more preferably 7 μm or more, and preferably 100 μm or less, still more preferably 80 μm or less.
The interfiber distance L1a of the constituent fibers (first fiber 14) on the first surface 10a side of the first layer 11 is preferably 10 μm or more, more preferably 15 μm or more, and preferably 100 μm or less, further preferably 80 μm or less. is there. The interfiber distance L1b of the constituent fibers (first fiber 14) on the second surface 10b side of the first layer 11 is preferably 5 μm or more, more preferably 7 μm or more, and preferably 80 μm or less, further preferably 70 μm. It is as follows. The interfiber distance L1a of the constituent fibers on the first surface 10a side of the first layer 11 is 50% of the thickness of the first layer 11 in the thickness direction Z from the first surface 10a of the first layer 11. The measurement target. Further, the interfiber distance L1b of the constituent fibers on the second surface 10b side of the first layer 11 is 50% of the thickness of the first layer 11 in the thickness direction Z from the first surface 10a of the first layer 11. The measurement target.
The interfiber distance L2 of the constituent fibers (second fiber 15) of the second layer 12 is preferably 7 μm or more, more preferably 10 μm or more, and preferably 200 μm or less, further preferably 150 μm or less.

Further, as described above, the laminated non-woven fabric 10 is provided with a sparse and dense gradient of fibers such that the fiber density increases from the second layer 12 to the first layer 11 (inside the thickness direction Z of the laminated structure 13) to absorb the liquid. The constituent fibers of the first layer 11 (first fibers 14) preferably have a smaller fiber diameter than the constituent fibers of the second layer 12 (second fibers 15) from the viewpoint of improving the above.
From the same viewpoint, it is preferable that the constituent fibers on the second surface 10b side of the first layer 11 have a smaller fiber diameter than the constituent fibers on the first surface 10a side of the first layer 11.
The fiber diameter is measured by the following method.

<Measuring method of fiber diameter>
A measurement target (fiber layer, laminated non-woven fabric) is cut with a razor (for example, a single blade manufactured by Feather Safety Shaving Blade Co., Ltd.) to obtain a measurement piece having a rectangular shape (8 mm × 4 mm) in a plan view. When cutting the measurement target, care should be taken so that the structure of the cut surface of the measurement piece formed by the cutting is not destroyed by the pressure at the time of cutting. A preferred method for cutting the measurement target is a method in which the measurement target is placed in liquid nitrogen to be sufficiently frozen prior to cutting the measurement target, and then cut. Using double-sided paper tape (Nichiban Co., Ltd. Nystack NW-15), attach the measurement piece to the sample table. The measurement piece is then platinum coated. An ion sputtering apparatus E-1030 (trade name) manufactured by Hitachi Naka Seiki Co., Ltd. is used for coating, and the sputtering time is 30 seconds. The cut surface of the measurement piece is observed at a magnification of 1000 times using an S-4000 type field emission scanning electron microscope manufactured by Hitachi, Ltd.

In the above-mentioned method for measuring the fiber diameter, when the constituent fibers (first fiber 14) of the first layer 11 are measured, the fibers 14 of the first layer 11 are the portions other than the interlayer joint portion 16 and are mutually. When the fibers of the entangled portion are selected and the constituent fibers of the second layer 12 (second fiber 15) are measured, the fibers of the second layer 12 are interlayer-bonded in the portion other than the interlayer bonding portion 16. Constituent fibers (second fiber 15) that are continuous between the parts and do not adhere to each other are selected. Then, for each of the first fiber 14 and the second fiber 15, the length in the width direction with respect to the longitudinal direction of the fiber is measured, and the average value thereof is taken as the fiber diameter. Further, when measuring the constituent fibers on the first surface 10a side of the first layer 11, the fibers located on the surface on the first surface 10a side other than the interlayer joint portion 16 are selected, and the first layer 11 When measuring the constituent fibers on the second surface 10b side, the fibers located on the surface on the second surface 10b side, which is a portion other than the interlayer joint portion 16, are selected.
When the measurement target is a composite non-woven fabric composed of a plurality of fiber layers having different fiber diameters such as SMS non-woven fabric and SMMS non-woven fabric, the liquid absorption in the first layer 11 is a melt blown layer in which the fibers are thin and the fiber density is high. In addition, the liquid absorbency from the second surface 10b side is greatly affected by the melt blown layer in which the fibers of the second layer 12 are thin and the fiber density is high. In consideration of the above, when the measurement target is a composite nonwoven fabric composed of a plurality of fiber layers having different fiber diameters and includes a melt blown layer, when measuring the fiber diameter, the fibers of the melt blown layer in the composite nonwoven fabric are used. The diameter will be measured.

As described above, it is assumed that the fiber diameter D1 of the constituent fibers of the first layer 11 (first fiber 14) is less than the fiber diameter D2 of the constituent fibers (second fiber 15) of the second layer 12 (D1 <D2). The ratio (D1 / D2) of the fiber diameter D1 of the constituent fibers (first fiber 14) of the first layer 11 to the fiber diameter D2 of the constituent fibers (second fiber 15) of the second layer 12 is preferably 0.05. Above, more preferably 0.06 or more, preferably 0.9 or less, still more preferably 0.8 or less.
The fiber diameter of the constituent fibers (first fiber 14) of the first layer 11 is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 30 μm or less, further preferably 20 μm or less.
The fiber diameter of the constituent fibers (first fiber 14) on the first surface 10a side of the first layer 11 is preferably 3 μm or more, more preferably 5 μm or more, and preferably 30 μm or less, further preferably 25 μm or less. The fiber diameter of the constituent fibers (first fiber 14) on the second surface 10b side of the first layer 11 is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 25 μm or less, further preferably 20 μm. It is as follows.
The fiber diameter of the constituent fibers (second fiber 15) of the second layer 12 is preferably 3 μm or more, more preferably 5 μm or more, and preferably 40 μm or less, further preferably 30 μm or less.

In the laminated structure of the laminated non-woven fabric according to the present invention, in addition to the above-mentioned first hydrophilic layer and second hydrophobic layer, other layers are added to the first layer 11 as long as the effects of the present invention are not impaired. It may be provided on the 1st surface 10a side or the 2nd surface 10b side of the 2nd layer 12. For example, in the laminated non-woven fabric 10 shown in FIG. 1, another layer may be arranged on the first surface 10a side of the first layer 11. That is, the laminated nonwoven fabric 10 comprises the other layer (not shown) forming the first surface 10a, the second layer 12 forming the second surface 10b, and the first layer 11 interposed between the two layers. It may have a multilayer structure of three or more layers including.

As another embodiment of the laminated structure of the laminated nonwoven fabric according to the present invention, in the laminated nonwoven fabric 10 shown in FIG. 1, an elastic member (not shown) is interposed between the first layer 11 and the second layer 12. Can be mentioned. When the laminated structure 13 is a multilayer structure in which a plurality of fiber layers of three or more layers are laminated as described above, the elastic member is not limited to between the first layer 11 and the second layer 12, and any of the plurality of fiber layers can be used. It can be interposed between layers. By interposing the elastic member between the layers of the laminated structure in this way, elasticity is imparted to the laminated nonwoven fabric, and the range of applications of the laminated nonwoven fabric can be further expanded.

The elastic member can be stretched, and when the force is released from the state where the elastic member is stretched 1.3 times the original length (1.3 times the original length), the elastic member is stretched. It is preferable to have the property (elasticity) of returning to a length of 1.1 times or less of the original length. The non-elastic member is a member that does not have such "elasticity", that is, a member that does not extend to a length of 1.3 times or more with respect to the original length without breaking the member, or When the force is released from the state where it is stretched 1.3 times the original length (it becomes 1.3 times the original length), it is 1.1 times or less of the original length. It is a member that does not return to its length. The form of the elastic member is not particularly limited, and any form such as a thread shape, a sheet shape, or an aggregate of elastic fibers (elastic fiber layer) can be selected. For example, in the laminated non-woven fabric 10 (laminated structure 13) shown in FIG. 1, a plurality of thread-like (filament-like) elastic members are interposed between the first layer 11 and the second layer 12 so as to extend in the same direction. In this case, the laminated non-woven fabric 10 (laminated structure 13) has elasticity in the extending direction of the elastic member.

As another embodiment of the laminated structure of the laminated nonwoven fabric according to the present invention, in the laminated nonwoven fabric 10 shown in FIG. 1, at least one of the first layer 11 and the second layer 12 is a sheet having elasticity in the width direction. The form is mentioned.
The elastic sheet is the above-mentioned sheet-like member having "elasticity". The sheet having no elasticity is a sheet-like member having no such "elasticity". The form of the sheet is, for example, (1) a stretchable non-woven fabric in which an stretchable fiber layer is integrated on both sides or one side of an elastic fiber layer, and (2) a fiber layer that can be stretched on both sides or one side of a net-shaped elastic sheet. Elastic non-woven fabric in which is integrated, (3) Elastic sheet in which elastic fiber layers made of elastic film are integrated on both sides or one side, (4) In one direction without intersecting each other A stretchable sheet or the like in which a large number of elastic filaments arranged so as to be stretched are bonded to a stretchable non-woven fabric over their entire length in a substantially non-stretched state can be preferably used.
As described above, since at least one of the first layer 11 and the second layer 12 is a sheet having elasticity in the width direction, elasticity is imparted to the laminated nonwoven fabric, and the range of applications of the laminated nonwoven fabric can be further expanded.

As the material of the elastic filament of the elastic member and the elastic sheet, a resin material of natural rubber or a thermoplastic elastomer can be used, and as the resin material of the thermoplastic elastomer, for example, SBS (styrene-butadiene-styrene), Styrene-based elastomers such as SIS (styrene-isoprene-styrene), SEBS (styrene-ethylene-butadiene-styrene), SEPS (styrene-ethylene-propylene-styrene), olefin-based elastomers (ethylene-based α-olefin elastomers, ethylene- Examples thereof include propylene-based elastomers obtained by copolymerizing butene and octene), polyester-based elastomers, and polyurethane-based elastomers.

Next, a method for producing a laminated nonwoven fabric according to the present invention will be described with reference to the drawings based on the preferred embodiment thereof. FIG. 4 shows an outline of an embodiment of a method for producing a laminated non-woven fabric.

In this manufacturing method, as shown in FIG. 4, a base sheet 11P is conveyed, and a heat-sealing fiber (second fiber 15), which is a long fiber obtained by spinning a resin on the base sheet 11P during the transfer, is obtained. ) To obtain a laminated body 10P, and an interlayer joining step of heating the laminated body 10P while partially compressing it in the thickness direction to form an interlayer joining portion 16.

Specifically, the base sheet 11P wound in a roll shape is unwound and conveyed in one direction indicated by the symbol MD by the transfer conveyor 50, and the spinning head arranged above the transfer conveyor 50 during the transfer. The second fiber 15 is spun from the spinneret of 51 and directly deposited on the base sheet 11P to obtain a laminate 10P. The second fiber 15 spun out is a heat-sealing fiber which is a long fiber. Then, the laminated body 10P is continuously conveyed and supplied between the pair of embossing rolls 52 and 53, and the laminated body 10P is subjected to thermal embossing to form an interlayer joining portion 16 (interlayer joining step). The embossing roll 52 is arranged above the laminated body 10P during transportation, and is in direct contact with the deposit (web) of the second fiber 15 spun during the thermal embossing process, and the embossing roll 53 is the laminated body during transportation. It is arranged below 10P and comes into contact with the base sheet 11P during thermal embossing. While the outer peripheral surface of the embossed roll 53 has no unevenness, a convex portion (not shown) is formed on the outer peripheral surface of the embossed roll 52 in a pattern corresponding to the pattern of the interlayer joint portion 16. At the nip portion between the rolls 52 and 53 having such a configuration, the laminate 10P is compressed in the thickness direction while being heated to a temperature equal to or higher than the melting point of the second fiber 15 contained therein, thereby compressing the laminate 10P. Is partially compressed from the deposit side of the second fiber 15 to the base sheet 11P side by the convex portion of the embossed roll 52, and the interlayer joint portion 16 is formed in the compressed portion. As a result, the deposit of the second fiber 15 becomes a non-woven fabric constituting the second layer 12, and is integrated with the base sheet 11P via the interlayer joint 16. Further, the second fiber 15 enters the base sheet 11P. That is, the molten constituent fibers (second fibers) enter between the constituent fibers of the first layer (base sheet 11P) that maintains the fiber morphology and solidify.

The laminated nonwoven fabric according to the present invention includes a form in which a plurality of second layers 12 are laminated and the laminated structure 13 has three or more layers. In the case of producing a laminated nonwoven fabric in such a form, the laminated fabric is laminated. In the step of obtaining the body 10P, the second fiber 15 may be deposited on the base sheet 11P a plurality of times. For example, in the above-mentioned manufacturing method, a plurality of spinning heads 51 may be intermittently arranged in the transport direction MD, and the second fibers 15 may be sequentially spun from each spinning head 51.

Since the base sheet 11P constitutes the first layer 11, it is preferably a non-woven fabric mainly composed of non-heat-sealing fibers. As such a non-woven fabric, a non-woven fabric in which non-heat-fused fibers are mixed with heat-fused fibers, a composite non-woven fabric in which non-heat-fused fibers are laminated or paper-made on a heat-fused non-woven fabric, and a higher density than the peripheral portion. In addition, a non-woven fabric having a compacted portion in which the constituent fibers (first fibers 14) are tightly packed with each other can be mentioned. Further, the base sheet 11P is more preferably a non-woven fabric mainly composed of hydrophilic non-heat-sealing fibers.
The base sheet 11P can be manufactured according to a conventional method according to the type of the base sheet 11P. Specifically, the base sheet 11P has a step of depositing raw material fibers such as a card method to obtain a fiber web, and embossing or the like in which the fiber web is partially compressed in the thickness direction to form a compacted portion. It may be manufactured through a compaction step, or may be manufactured by a known non-woven fabric making technique such as a water flow entanglement method or a needle punching method that does not include the compaction step.

Further, the raw material fiber of the base sheet 11P may be subjected to the above-mentioned hydrophilic treatment to impart hydrophilicity to the base sheet 11P. In that case, the hydrophilization treatment is performed at least before the second fiber 15 is directly deposited. Further, when the hydrophilization treatment is performed by coating with a hydrophilic agent, the above-mentioned coating method can be used.

In the present manufacturing method, it is preferable to perform a calendar treatment on the laminated body 10P (laminated non-woven fabric 10) before or after the interlayer bonding step. As a result, the penetration of the second fiber 15 into the base sheet 11P is further promoted, so that various properties such as liquid absorption and strength of the laminated non-woven fabric 10 can be further improved. As is well known, the calender process is a process of applying heat and pressure to a fiber aggregate such as a non-woven fabric with a calendar roll to increase the density of the fiber aggregate. The number and arrangement of calendar rolls used for calendar processing are not particularly limited. For example, a series type or inclined type composed of three calendar rolls, a series type composed of four calendar rolls, and an inverted L type. , Z type or inclined Z type, Z type or L type composed of five calendar rolls can be used. Further, the temperature in the calendering process is preferably equal to or lower than the softening point of the constituent fibers of the laminated body 10P (laminated non-woven fabric 10) as the workpiece. If the calendar treatment is performed above the softening point, the non-woven fabric may become hard and the texture may deteriorate.

Further, the base sheet 11P may be subjected to calendar processing before the laminated body 10P is obtained. As a result, the interfiber distance of the base sheet 11P is reduced and the capillary pressure is increased, so that the liquid absorption is increased. Therefore, the hydrophobic second layer has a relatively large interfiber distance and a low basis weight. However, the effect that the second surface 10b side becomes dry after the liquid is absorbed is exhibited. In short, the timing of carrying out the calendar processing in the present manufacturing method may be immediately before or immediately after the interlayer bonding step, before depositing the second fiber 15 on the base sheet 11P, or both.

Further, calendar processing may be adopted in the manufacturing process of the base sheet 11P. That is, the precursor of the base sheet 11P may be subjected to a calendar treatment immediately before or immediately after the consolidation step.

As described above, in the laminated nonwoven fabric according to the present invention, an elastic member having a form such as a thread-like, a sheet-like, or an aggregate of elastic fibers (elastic fiber layer) is interposed between the first layer and the second layer. The formed form is included. In the case of producing a laminated non-woven fabric having such a structure in which elastic members are interposed between layers of the laminated structure, the elastic members are placed on the base sheet 11P before the second fibers 15 are deposited on the base sheet 11P. You can arrange it. The method of arranging such elastic members may be appropriately selected according to the form of the elastic members and the like. For example, when an elastic fiber layer, which is an aggregate of elastic fibers, is arranged as an elastic member, the elastic fibers can be directly spun on the base sheet 11P in the same manner as the second fiber 15.

Hereinafter, the absorbent article of the present invention will be described based on its preferred embodiment with reference to the drawings. The absorbent article of the present invention is characterized in that it comprises the above-mentioned laminated non-woven fabric. More specifically, as described above, the laminated nonwoven fabric according to the present invention has a laminated structure in which a plurality of fiber layers are laminated, and the laminated structure is one surface of the laminated nonwoven fabric, that is, a first surface and the other. A place having a second surface which is a surface and having a hydrophilic first layer forming the first surface and a hydrophobic second layer located on the second surface side of the first layer. In the absorbent article of the present invention, the laminated nonwoven fabric is arranged with the second surface facing the wearer's skin side.

5 to 7 show a pants-type disposable diaper 1 which is an embodiment of the absorbent article of the present invention. Regarding the diaper 1, a component different from the laminated non-woven fabric 10 which is the embodiment of the above-mentioned laminated non-woven fabric will be mainly described, and the same components will be designated by the same reference numerals and the description thereof will be omitted. The description of the laminated non-woven fabric 10 is appropriately applied to the components not particularly described.

As shown in FIGS. 5 and 6, the diaper 1 includes a ventral region A and a dorsal region B in the vertical direction X, and an inseam region C located between the ventral regions A and B. The ventral waist flap FA and the dorsal waist flap, which have an absorber 23 over the dorsal region B and are located outward from each of the front and rear ends 23A and 23B of the absorber 23 in the vertical direction X and extend in the lateral direction Y. Has an FB. Here, the ventral area A is an area arranged on the ventral side of the wearer when wearing an absorbent article such as a disposable diaper, and the dorsal area B is an area arranged on the ventral side of the wearer when wearing an absorbent article such as a disposable diaper. It is an area arranged on the dorsal side of. The ventral region A and the dorsal region B are waist circumferences corresponding to the wearer's waist circumference when the diaper 1 is worn.

As shown in FIG. 6, the ventral waist flap FA is located outward from the edge of the front end portion 23A on the ventral region A side of the absorber 23 in the longitudinal direction X and extends in the lateral direction Y. It means a region including a region and a region extending in the lateral direction Y from the front end portion 23A on the ventral side region A side of the absorber 23 in the vertical direction X. Further, the dorsal waist flap FB is a region located outside the longitudinal direction X and extending in the lateral direction Y from the edge of the rear end portion 23B on the dorsal region B side of the absorber 23 in the vertical direction X, and absorption. It means a region including a region extending in the lateral direction Y from the rear end portion 23B on the dorsal region B side of the body 23 in the vertical direction X.

As shown in FIGS. 5 and 6, the diaper 1 includes an absorbent body 2 and an exterior body 3 arranged on the non-skin contact surface side of the absorbent body 2 and fixing the absorbent body 2. The exterior body 3 has a ventral waist flap FA and a dorsal waist flap FB located outward from the front and rear ends 23A and 23B of the absorber 23 constituting the absorbent body 2 in the vertical direction X and extending in the lateral direction Y. Have. In the diaper 1, elastic regions (waist elastic portion G1 and lower waist elastic portion G2) are formed in the ventral waist flap FA and the dorsal waist flap FB.

As shown in FIG. 6, the diaper 1 is a pair in which the left and right side edge portions 3a1, 3a1 of the ventral region A of the exterior body 3 and the left and right side edge portions 3b1, 3b1 of the dorsal region B of the exterior body 3 are joined. This is a so-called pants-type disposable diaper in which the side seal portions S, S, the waist opening WO, and the pair of leg openings LO, LO are formed (see FIG. 5). Preferably, the exterior body 3 of the diaper 1 has a ventral region A arranged on the ventral side of the wearer when worn, and the wearer's outer body 3 when worn, in a plan view of the unfolded and stretched state shown in FIG. It is divided into a dorsal region B arranged on the dorsal side and an inseam region C between the ventral region A and the dorsal region B. As shown in FIG. 6, the unfolded and extended state of the diaper 1 as used herein means that the side seal portion S is peeled off to bring the diaper 1 into the unfolded state, and the diaper 1 in the unfolded state is set to the elastic member of each part. It means a state in which the diaper is stretched and expanded to the design dimension (the same as the dimension when the diaper is expanded in a plane with the influence of the elastic member completely excluded).

In the present specification, the "skin contact surface" is a surface of the diaper 1 or its constituent members (for example, the absorbent body 2) that faces the wearer's skin side when worn, and is a "non-skin contact surface". Is a surface of the diaper 1 or its constituent members that is directed to the side opposite to the wearer's skin side (clothing side) when worn. Further, in the diaper 1, the vertical direction X is a direction corresponding to a direction extending from the ventral side of the wearer to the dorsal side via the crotch portion, and the abdomen is in a state where the diaper 1 is expanded and extended in a plane. This is the direction from the side region A to the dorsal region B. Further, the horizontal direction Y is a direction orthogonal to the vertical direction X, and is the width direction of the diaper 1 in a state of being expanded and extended in a plane. Further, the diaper 1 has a symmetrical shape with respect to the vertical center line CL1 extending in the vertical direction X as shown in FIG. CL2 in FIG. 6 is a horizontal center line extending in the horizontal direction Y that divides the diaper 1 into two, and is orthogonal to the vertical center line CL1.

In the diaper 1, as shown in FIG. 6, the absorbent main body 2 has a vertically long shape in which the vertical direction X is relatively long in the unfolded and extended state of the diaper 1. The absorbent body 2 includes a liquid-permeable front sheet 21 that forms a skin contact surface, a liquid-impervious (including water-repellent) back surface sheet 22 that forms a non-skin contact surface, and both of these sheets 21. , A liquid-retaining absorber 23 interposed between 22 and 22 is provided. Further, as shown in FIG. 6, leakage-proof cuffs 24 and 24 having elastic members arranged in an extended state in the vertical direction X are provided on both side portions of the absorbent main body 2 along the vertical direction X (longitudinal direction). Has been done. Specifically, the leak-proof cuff 24 is made of a liquid-impermeable or water-repellent and breathable material, and an elastic member for forming a leak-proof cuff is located near the free end of each leak-proof cuff 24. 25 is arranged in a state of being extended in the vertical direction X. When wearing a diaper, the contraction of the elastic member 25 for forming the leak-proof cuff causes the free end side of the leak-proof cuff 24 to stand up to prevent the outflow of body fluid in the lateral direction Y.

As shown in FIG. 6, the absorbent main body 2 configured as described above is fixed to the central portion of the exterior body 3 by matching the longitudinal direction thereof with the vertical direction X of the diaper 1 in the expanded and extended state. It is joined by a diaper. In this way, the exterior body 3 is arranged and adhesively fixed to the non-skin contact surface side of the back surface sheet 22 constituting the absorbent body 2 in the thickness direction of the disposable diaper 1. Therefore, in the diaper 1, the absorbent body 23 constituting the absorbent main body 2 is arranged over the ventral region A and the dorsal region B.

In the diaper 1, as shown in FIG. 6, the exterior body 3 is located outward from each of the front and rear ends 23A and 23B of the absorber 23 in the vertical direction X and extends in the lateral direction Y, and the ventral waist flap FA and the back. It has a side waist flap FB. As shown in FIGS. 5 to 7, the exterior body 3 is an outer layer sheet 6 on the non-skin contact surface side forming the outer surface of the diaper 1, and an inner layer sheet 3i arranged on the skin contact surface side of the outer layer sheet 6. The outer layer sheet 6 includes a folded-back portion 6R in which the extending portion extending from the front-rear end portion of the inner layer sheet 3i in the vertical direction X is folded back toward the skin contact surface side of the inner layer sheet 3i. As shown in FIG. 6, the folded-back portion 6R of the outer layer sheet 6 is formed in a rectangular shape long in the lateral direction Y. The front and rear ends 23A and 23B of the absorbent body 2 are each covered with the folded-back portion 6R.

As described above, the diaper 1 has a ventral region A and a dorsal region B as a waist circumference corresponding to the wearer's waist circumference when worn, and both regions A and B are shown in FIG. In addition, at least the waist expansion / contraction portion G1 and the waist circumference lower expansion / contraction portion G2 are formed as the expansion / contraction region, and further, the leg expansion / contraction portion G3 may be formed. That is, the exterior body 3 is intermittently arranged in the vertical direction X in both regions A and B in a state of being extended in the horizontal direction Y between the outer layer sheet 6 and the inner layer sheet 3i constituting the exterior body 3. A plurality of elastic members 71 are provided, whereby a waist elastic portion G1 and a waist circumference lower elastic portion G2 are formed in both regions A and B as elastic regions having elasticity in the lateral direction Y. Further, the exterior body 3 includes a plurality of leg elastic members 72 arranged in a state of being extended in a predetermined direction between the outer layer sheet 6 and the inner layer sheet 3i from both regions A and B to the inseam region C. As a result, leg stretchable portions G3 can be formed as stretchable regions in these regions A, B, and C.

In the diaper 1, as shown in FIGS. 5 and 6, the waist telescopic portion G1 is the edge of the front and rear ends 23A and 23B of the absorber 23 constituting the absorbent body 2 in the vertical direction X in the vertical direction X. It is formed on an end flap located on the outer side of the vertical direction X (the side opposite to the horizontal center line CL2 side). Further, in the diaper 1, the lower waist elastic portion G2 is formed on a side flap located between the lower end of the waist elastic portion G1 on the horizontal center line CL2 side and the lower end of the side seal portion S in the vertical direction X. ing. The dorsal waist flap FB and the ventral waist flap FA described above are also regions in which a part of the side flap (lower waist elastic portion G2) is combined with the end flap (waist elastic portion G1). Further, in the diaper 1, the leg expansion / contraction portion G3 is formed at the peripheral portion of the leg opening LO as shown in FIGS. 5 and 6.

As shown in FIGS. 5 to 7, the diaper 1 includes a sweat absorbing sheet 10 (see FIG. 1) capable of absorbing sweat. The sweat absorbing sheet 10 is one of the above-mentioned laminated nonwoven fabrics according to the present invention. The laminated non-woven fabric 10 according to the embodiment. The sweat absorbing sheet 10 is arranged with the second surface 10b (the outer surface of the hydrophobic second layer 12) facing the wearer's skin side.

In the diaper 1, the sweat absorbing sheet 10 is mainly intended for absorbing sweat around the waist of the wearer, and is arranged around the waist as described above. More specifically, the sweat absorbing sheet 10 is arranged in the elastic region around the waist. That is, the sweat absorbing sheet 10 has a long shape in one direction in a plan view as shown in FIG. 6, specifically, a rectangular shape (strip shape), and the longitudinal direction thereof coincides with the lateral direction Y, and the ventral side around the waist. It is arranged over the entire length of the lateral direction Y of each of the region A and the dorsal region B, and is arranged at least over the waist elastic portion G1 and the lower waist elastic portion G2. Specifically, the sweat absorbing sheet 10 is bonded to the skin contact surface of the folded portion 6R of the outer layer sheet 6 by a known bonding means such as an adhesive, a heat seal, or an ultrasonic seal. The folded-back portion 6R is arranged closer to the wearer's skin than the absorber 23 when the diaper 1 is worn (see FIG. 7), and therefore, the sweat-absorbing sheet arranged on the skin contact surface of the folded-back portion 6R. 10 is arranged closer to the wearer's skin than the absorber 23 when the diaper 1 is worn, and can come into contact with the wearer's skin.

In the diaper 1 having the above configuration, the sweat absorbing sheet 10 (laminated non-woven fabric 10) having a sweat absorbing function is a diaper on the skin contact surface side of each of the ventral region A and the dorsal region B around the waist. 1 is arranged closest to the skin of the wearer, and the area where the sweat absorbing sheet 10 is arranged is an elastic region having elasticity in the lateral direction Y including the waist elastic portion G1 and the lower waist elastic portion G2. When the diaper 1 is worn, the hydrophobic second surface 10b (see FIG. 1) of the sweat absorbing sheet 10 comes into contact with the wearer's skin with good fit and radiates from the skin due to the tightening caused by the contraction force of the elastic region. Can absorb sweat quickly. Moreover, even after absorbing sweat, it is not sticky to the skin and feels good on the skin. As described above, the sweat absorbing sheet 10 (laminated non-woven fabric 10) can be preferably used as a sheet for absorbent articles.

In the diaper 1, as described above, the sweat absorbing sheet 10 (laminated non-woven fabric 10) is arranged in the stretchable region. Therefore, from the viewpoint of improving the fit to the wearer's skin, the sweat absorbing sheet 10 is also in the same direction as the stretchable region. That is, it is preferable to have elasticity in the lateral direction Y. From such a viewpoint, it is preferable that an elastic member (stretchable member) having elasticity in the lateral direction Y is arranged between the first layer 11 and the second layer 12 of the sweat absorbing sheet 10. This elastic member is as described above.

Explaining the material for forming each part of the diaper 1, the front surface sheet 21, the back surface sheet 22, the absorber 23, the leakage-proof cuff 24, and the like constituting the absorbent body 2 have been conventionally used for absorbent articles such as disposable diapers. Various kinds of diapers can be used without particular limitation. For example, as the surface sheet 21, a non-woven fabric having a single-layer or multi-layer structure, a perforated film, or the like can be used. As the back sheet 22, a moisture-permeable resin film or the like can be used. As the absorber 23, one in which an absorbent core composed of absorbent polymer particles and a fiber material is coated with tissue paper can be used. Further, as the leak-proof cuff 24, a water-repellent single-layer or multi-layered non-woven fabric or the like can be used. Examples of the elastic member (elastic member 25 for forming a leak-proof cuff, elastic member 71, leg elastic member 72, etc.) include synthetic rubber such as styrene-butadiene, butadiene, isoprene, neoprene, natural rubber, EVA, and elasticity. Butadiene, polyurethane and the like can be mentioned. As the form of the elastic member, a thread-like (thread rubber or the like) or a string-like (flat rubber or the like) having a rectangular, square, circular, elliptical, or polygonal cross section can be preferably used. Further, as a joining means for joining the constituent members of the diaper 1, various adhesives such as a hot melt adhesive conventionally used for this kind of absorbent article can be used.

Although the present invention has been described above based on the embodiment, the present invention can be appropriately modified without being limited to the embodiment.
For example, in diaper 1, the laminated non-woven fabric 10 is used as a sweat-absorbing sheet, but in the absorbent article of the present invention, the laminated non-woven fabric 10 wears the second surface (hydrophobic surface having an interlayer joint). If it is arranged toward the skin side, it can be used as a component other than the sweat-absorbing sheet, and even when it is used as a sweat-absorbing sheet, the arrangement location is the arrangement of the sweat-absorbing sheet 10 in the diaper 1. It is not limited to the location. For example, another use of the laminated non-woven fabric includes a surface sheet arranged at a position closer to the wearer's skin than the absorber. That is, in the diaper 1, the laminated non-woven fabric 10 can be used as the surface sheet 21. As described above, the laminated non-woven fabric 10 can be preferably used as a sheet for absorbent articles.

Further, in the exterior body 3 of the diaper 1, as shown in FIG. 6, the elastic member 71 is arranged between the outer layer sheet 6 and the inner layer sheet 3i, but the elastic member 71 may not be arranged. When the elastic region is formed in a form in which the elastic member 71 is not arranged, an elastic non-woven fabric having elasticity in the lateral direction Y may be used as a constituent member of the exterior body 3.
Further, in the diaper 1, as shown in FIG. 6, the exterior body 3 has a continuous shape extending over the ventral region A, the inseam region C, and the dorsal region B. Instead, the exterior body 3 has a continuous shape. It may have a divided shape divided into a ventral exterior body arranged on the ventral side of the wearer and a dorsal exterior body arranged on the dorsal side of the wearer. Further, the exterior body 3 may have a divided shape divided into a ventral exterior body, a dorsal exterior body, and an inseam exterior body arranged between the ventral exterior body and the dorsal exterior body. .. When the exterior body 3 is a split type as described above, at least one of the ventral exterior body and the dorsal exterior body, more preferably at least the dorsal exterior body, is configured to include the above-mentioned laminated non-woven fabric.
Further, the absorbent article of the present invention is not limited to the pants-type disposable diaper such as the above-mentioned diaper 1, and can be applied to all articles used for absorbing body fluids. For example, a deployable disposable diaper and a sanitary napkin. Can be applied to.
Furthermore, the sweat-absorbing sheet of the present invention is not limited to the above-mentioned application to the absorbent article, and can be applied to articles other than the absorbent article. For example, the sweat absorbing sheet of the present invention can be used as the sheet itself used by the user to wipe the sweat. In addition, it can be applied to insoles for shoe soles, armpit sweat pads, eye masks, face masks, etc., and by arranging the sweat absorbing sheet of the present invention toward the wearer's skin side, the soles and armpits , Can quickly absorb sweat radiating from the face. Further, when applied to a face mask or the like that keeps in contact with the skin even after absorbing sweat, the skin is not sticky and feels good on the skin.
The following additional notes will be further disclosed with respect to the above-described embodiments of the present invention.

<1>
An absorbent article comprising a laminated non-woven fabric having a laminated structure in which a plurality of fiber layers are laminated.
The laminated non-woven fabric has a first surface which is one surface and a second surface which is the other surface, and is formed on a hydrophilic first layer forming the first surface and a second surface side of the first layer. It has a second layer of hydrophobicity located and
The first layer is composed of non-heat-fused fibers.
The second layer is mainly composed of heat-sealing fibers, which are long fibers.
The laminated non-woven fabric has a thickness smaller than that of the peripheral portion, and partially has an interlayer bonding portion in which the layers constituting the laminated structure are bonded to each other in a plan view of the laminated non-woven fabric.
The portion having the interlayer joint is recessed from the second surface side toward the first surface side.
The constituent fibers of the first layer at the interlayer joint maintain the fiber morphology.
The constituent fibers of the second layer at the interlayer joint are melted, and a part of the melted constituent resin enters between the constituent fibers of the first layer and is solidified.
The laminated non-woven fabric is arranged with the second surface facing the wearer's skin side.
An absorbent article in which the absorbent article has a waist circumference corresponding to the wearer's waist and the laminated non-woven fabric is arranged around the waist.

<2>
In the portion of the first layer that overlaps with the interlayer joint portion in the thickness direction of the laminated non-woven fabric, a portion of the second layer in which the molten constituent resin has entered and a portion in which the molten constituent resin has not entered are formed. The absorbent article <3> according to <1> above.
The second layer partially has a melt-bonded portion in which the heat-sealing fibers are bonded to each other in a plan view of the laminated non-woven fabric.
The absorbent article according to <1> or <2>, wherein the melt joint portion constitutes the second layer portion of the interlayer joint portion.
<4>
The absorbent article according to any one of <1> to <3>, wherein the stretchable region is provided around the waist and the laminated non-woven fabric is arranged in the stretchable region.
<5>
The absorbent article comprises a liquid-retaining absorber.
The absorbent article according to any one of <1> to <4>, wherein the laminated non-woven fabric is arranged at a position closer to the wearer's skin than the absorbent body.
<6>
The absorbent article includes an absorbent body provided with a liquid-retaining absorber and an exterior body fixed to the non-skin contact surface side of the absorbent body.
The exterior body has a ventral exterior body arranged on the ventral side of the wearer and a dorsal exterior body arranged on the dorsal side, and at least the dorsal exterior body is configured to include the laminated non-woven fabric. And
The absorbent article according to any one of <1> to <5>, wherein the laminated non-woven fabric is arranged with the second surface facing the skin side of the wearer.
<7>
The combined basis weight of the first layer and the second layer of the laminated non-woven fabric is preferably 11 g / m ² or more, more preferably 14 g / m ² or more, and preferably 55 g / m ² or less, further preferably 50 g. The absorbent article according to any one of <1> to <6>, which is / m ² or less.
<8>
The absorbent article according to any one of <1> to <7>, wherein the first layer of the laminated non-woven fabric has a basis weight of 8 g / m ² or more and 40 g / m ² or less.
<9>
The basis weight of the first layer of the laminated non-woven fabric is preferably 8 g / m ² or more, more preferably 11 g / m ² or more, and preferably 40 g / m ² or less, still more preferably 35 g / m ² or less. The absorbent article according to any one of <1> to <8>.
<10>
The absorbent article according to any one of <1> to <9>, wherein the second layer of the laminated non-woven fabric has a basis weight of 3 g / m ² or more and 25 g / m ² or less.

<11>
The basis weight of the second layer of the laminated non-woven fabric is preferably 3 g / m ² or more, more preferably 5 g / m ² or more, and preferably 25 g / m ² or less, more preferably 15 g / m ² or less, still more preferable. The absorbent article according to any one of <1> to <10>, wherein the amount is 13 g / m ² or less.
<12>
The total area of the interlayer joint portion of the laminated nonwoven fabric is 15% or less with respect to the total area of the laminated nonwoven fabric.
The absorbent article according to any one of <1> to <11>, wherein the area of each interlayer joint is 1 mm ² or less.
<13>
The area ratio of the laminated non-woven fabric is preferably 5% or more, more preferably 6% or more, and preferably 15% or less, still more preferably 12% or less, according to any one of <1> to <12>. The absorbent article described.
<14>
The area of the interlayer joint on the second surface is preferably 0.1 mm ² or more, more preferably 0.15 mm ² or more, and preferably 1 mm ² or less, further preferably 0.8 mm ² or less. The absorbent article according to any one of <1> to <13>.
<15>
The first layer of the laminated non-woven fabric is mainly composed of non-heat-fused fibers, and at least 50% of the constituent fibers of the first layer are non-heat-fused fibers. 14> The absorbent article according to any one of.
<16>
The absorbent article according to any one of <1> to <15>, wherein the non-heat-sealing fiber is a natural fiber, a regenerated cellulose fiber or a semi-synthetic fiber.
<17>
The absorbent article according to any one of <1> to <16>, wherein the non-heat-sealing fiber is a short fiber.
<18>
The absorbent article according to any one of <1> to <17>, wherein the first layer has a smaller inter-fiber distance between constituent fibers than the second layer.
<19>
The ratio (L1 / L2) of the interfiber distance L2 of the constituent fibers of the second layer to the interfiber distance L1 of the constituent fibers of the first layer is preferably 1.1 or more, more preferably 10 or more, and preferably. The absorbent article according to <18> above, wherein is 70 or less, more preferably 50 or less.
<20>
The interfiber distance L1 of the constituent fibers of the first layer is preferably 5 μm or more, more preferably 7 μm or more, and preferably 100 μm or less, further preferably 80 μm or less, according to <18> or <19>. Absorbent article.

<21>
Any of the above <18> to <20>, wherein the interfiber distance L2 of the constituent fibers of the second layer is preferably 7 μm or more, more preferably 10 μm or more, and preferably 200 μm or less, further preferably 150 μm or less. The absorbent article according to 1.
<22>
The absorbent article according to any one of <1> to <21>, wherein the constituent fibers of the first layer of the laminated nonwoven fabric have a smaller fiber diameter than the constituent fibers of the second layer.
<23>
The ratio (D1 / D2) of the fiber diameter D1 of the constituent fibers of the first layer to the fiber diameter D2 of the constituent fibers of the second layer is preferably 0.05 or more, more preferably 0.06 or more, and preferably 0.06 or more. The absorbent article according to <22> above, wherein is 0.9 or less, more preferably 0.8 or less.
<24>
<22> or <23>, wherein the fiber diameter D1 of the constituent fibers of the first layer is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 30 μm or less, further preferably 20 μm or less. Absorbent article.
<25>
Any one of <22> to <24>, wherein the fiber diameter D2 of the constituent fibers of the second layer is preferably 3 μm or more, more preferably 5 μm or more, and preferably 40 μm or less, further preferably 30 μm or less. Absorbent article described in.
<26>
The constituent fibers on the second surface side of the first layer of the laminated non-woven fabric have higher hydrophilicity than the constituent fibers on the first surface side of the first layer, said <1> to <25>. The absorbent article according to any one of.
<27>
The constituent fibers on the second surface side of the first layer of the laminated non-woven fabric have a smaller inter-fiber distance than the constituent fibers on the first surface side of the first layer, said <1> to <26. > The absorbent article according to any one of.
<28>
In <27>, the interfiber distance L1a of the constituent fibers on the first surface side of the first layer is preferably 10 μm or more, more preferably 15 μm or more, and preferably 100 μm or less, further preferably 80 μm or less. The absorbent article described.
<29>
The interfiber distance L1b of the constituent fibers on the second surface side of the first layer is preferably 5 μm or more, more preferably 7 μm or more, and preferably 80 μm or less, still more preferably 70 μm or less. The absorbent article according to <28>.
<30>
The constituent fibers on the second surface side of the first layer have a smaller fiber diameter than the constituent fibers on the first surface side of the first layer, and any one of <1> to <29>. Absorbent article described in.

<31>
The fiber diameter of the constituent fibers on the first surface side of the first layer is preferably 3 μm or more, more preferably 5 μm or more, and preferably 30 μm or less, still more preferably 25 μm or less, according to the above <30>. Absorbent article.
<32>
The fiber diameter of the constituent fibers on the second surface side of the first layer is preferably 0.5 μm or more, more preferably 1 μm or more, and preferably 25 μm or less, still more preferably 20 μm or less. The absorbent article according to <31>.
<33>
The absorbent article according to any one of <1> to <32>, wherein an elastic member is interposed between the layers of the plurality of fiber layers of the laminated non-woven fabric.
<34>
The laminated nonwoven fabric has any one of <1> to <33>, wherein at least one of the first layer and the second layer has elasticity in the width direction orthogonal to the longitudinal direction of the absorbent article. Absorbent article described in.
<35>
The absorbent article according to any one of <1> to <34>, wherein the first layer contains at least 50% by mass of hydrophilic fibers.
<36>
The absorbent article according to any one of <1> to <35>, wherein the second layer is mainly composed of hydrophobic fibers and contains at least 90% by mass or more of hydrophobic fibers.
<37>
The contact angle of the constituent fibers of the second layer is larger than that of the constituent fibers of the first layer, and the contact angle of the constituent fibers of the second layer is preferably 95 degrees or more, more preferably 100 degrees or more. The absorbent article according to any one of <1> to <36>, preferably 150 degrees or less, more preferably 130 degrees or less.
<38>
The contact angle of the constituent fibers of the first layer is smaller than that of the constituent fibers of the second layer, and the contact angle of the constituent fibers of the first layer is preferably 5 degrees or more, more preferably 10 degrees or more. The absorbent article according to any one of <1> to <37>, preferably 88 degrees or less, more preferably 85 degrees or less.
<39>
In addition to the interlayer joint portion, the first layer has a compacted portion having a thickness smaller than that of the peripheral portion and the constituent fibers of the first layer being densified with each other.
The area per one of the consolidated portions is preferably 0.1 mm ² or more, more preferably 0.15 mm ² or more, and preferably 1 mm ² or less, further preferably 0.8 mm ² or less. The absorbent article according to any one of <38>.

<40>
It has a laminated structure in which a plurality of fiber layers are laminated, has a first surface and a second surface located on the opposite side to the first surface, and the second surface is used toward the skin side of the wearer. It ’s a sweat-absorbing sheet,
It has a hydrophilic first layer forming the first surface and a hydrophobic second layer located on the second surface side of the first layer.
The first layer is composed of non-heat-fused fibers.
The second layer is mainly composed of heat-sealing fibers, which are long fibers.
The sweat-absorbing sheet has a thickness smaller than that of the peripheral portion, and partially has an interlayer joint portion in which the layers constituting the laminated structure are bonded to each other in a plan view of the laminated non-woven fabric.
The portion having the interlayer joint is recessed from the second surface side toward the first surface side.
The constituent fibers of the first layer at the interlayer joint maintain the fiber morphology.
A sweat-absorbing sheet in which the constituent fibers of the second layer at the interlayer joint are melted, and a part of the melted constituent resin enters between the constituent fibers of the first layer and is solidified.

According to the present invention, there are provided an absorbent article and a sweat-absorbing sheet which are less likely to cause liquid return and have excellent absorption performance of body fluids such as sweat and urine.

As described above, the interlayer joint portion 16 in the recess 17 has a higher density of the constituent resin than the periphery of the recess 17, so that liquid such as sweat easily adheres to the interlayer joint portion 16 and from the peripheral edge of the interlayer joint portion 16. In the vicinity thereof, the fiber morphology of the constituent fibers (second fiber 15) of the second layer is maintained as compared with the interlayer joint portion 16, so that the liquid is applied to the plurality of second fibers 15 in which the fiber morphology is maintained. By adhering, the liquid easily enters between the second fibers 15. That is, the liquid that has entered the recess 17 is likely to be drawn into the first surface 10a side from the peripheral edge of the interlayer joint 16 in the recess 17 and its vicinity. In this way, the peripheral edge of the interlayer joint 16 in the recess 17 and its vicinity serve as a liquid drawing portion.
Further, in the interlayer joint 16, the constituent fibers of the first layer 11 maintain the fiber morphology, and a part of the constituent fibers of the second layer is melted between the constituent fibers of the first layer 11. Since the resin 15a is contained, the liquid is transferred to the second surface of the interlayer joint portion 16 by allowing the first fiber 14 of the first layer to coexist between the second fibers 15 of the second layer. It is easy to pull in from the 10b side to the first surface 10a side.
Further, since the second layer is mainly composed of long fibers, the second fibers 15 are oriented in the plane direction of the laminated non-woven fabric, and the thickness is small and the thickness is further reduced by the formation of the interlayer joint portion 16. It is easy to do so, and the liquid that has entered the peripheral edge of the interlayer joint 16 and its vicinity easily comes into contact with the hydrophilic first fibers 14 of the first layer 11, so that the liquid on the second surface 10b side is easily absorbed.
As described above, the laminated non-woven fabric 10 includes the above-mentioned hydrophilicity gradient, the peripheral edge of the interlayer bonding portion 16 acting as a liquid drawing portion and its vicinity, and the second fiber 15 which is a hydrophobic constituent fiber of the second layer 12. It is excellent because it has a portion where the first fiber 14 which is the hydrophilic constituent fiber 14 of the first layer 11 coexists and a thin portion of the second layer 12 where the distance to the first layer 11 is small. Has absorption performance.

The second layer 12 of the present embodiment partially has a melt-bonded portion in which heat-sealing fibers are bonded to each other in a plan view of the laminated non-woven fabric. The melt-bonded portion is a portion where the constituent fibers of the second layer 12 are melt-solidified. From the viewpoint of improving the drawing of the liquid, it is preferable that the melt joint portion constitutes the second layer portion of the interlayer joint portion 16. That is, it is preferable that the melt-bonded portion constitutes a portion of the second layer 12 of the interlayer-bonded portion 16 in the thickness direction of the laminated non-woven fabric, that is, a portion in which the constituent fibers of the second layer of the interlayer-bonded portion 16 are melted. In this case, the constituent fibers (second fibers) melted at the melt-bonded portion enter between the constituent fibers of the first layer 11 that maintain the fiber morphology and are solidified. Further, it is preferable that more than half of the melt joints form the second layer portion of the interlayer joint 16, and all of the melt joints form the second layer portion of the interlayer joint 16. Is more preferable.

As described above, the interfiber distance L1 of the constituent fibers of the first layer 11 (first fiber 14) <the interfiber distance L2 of the constituent fibers (second fiber 15) of the second layer 12 (L1 <L2). As a premise, the ratio (L2 / L1) of the interfiber distance L2 of the constituent fibers (second fiber 15) of the second layer 12 to the interfiber distance L1 of the constituent fibers of the first layer 11 (first fiber 14) is preferable. Is 1.1 or more, more preferably 10 or more, and preferably 70 or less, still more preferably 50 or less.
The interfiber distance L1 of the constituent fibers (first fiber 14) of the first layer 11 is preferably 5 μm or more, more preferably 7 μm or more, and preferably 100 μm or less, still more preferably 80 μm or less.
The interfiber distance L1a of the constituent fibers (first fiber 14) on the first surface 10a side of the first layer 11 is preferably 10 μm or more, more preferably 15 μm or more, and preferably 100 μm or less, further preferably 80 μm or less. is there. The interfiber distance L1b of the constituent fibers (first fiber 14) on the second surface 10b side of the first layer 11 is preferably 5 μm or more, more preferably 7 μm or more, and preferably 80 μm or less, further preferably 70 μm. It is as follows. The interfiber distance L1a of the constituent fibers on the first surface 10a side of the first layer 11 is 50% of the thickness of the first layer 11 in the thickness direction Z from the first surface 10a of the first layer 11. The measurement target. Further, the interfiber distance L1b of the constituent fibers on the second surface 10b side of the first layer 11 is 50% of the thickness of the first layer 11 in the thickness direction Z from the surface of the second surface 10b in the first layer 11. The part is the measurement target.
The interfiber distance L2 of the constituent fibers (second fiber 15) of the second layer 12 is preferably 7 μm or more, more preferably 10 μm or more, and preferably 200 μm or less, further preferably 150 μm or less.

Claims (19)

An absorbent article comprising a laminated non-woven fabric having a laminated structure in which a plurality of fiber layers are laminated.
The laminated non-woven fabric has a first surface which is one surface and a second surface which is the other surface, and is formed on a hydrophilic first layer forming the first surface and a second surface side of the first layer. It has a second layer of hydrophobicity located and
The first layer is composed of non-heat-fused fibers.
The second layer is mainly composed of heat-sealing fibers, which are long fibers.
The laminated non-woven fabric has a thickness smaller than that of the peripheral portion, and partially has an interlayer bonding portion in which the layers constituting the laminated structure are bonded to each other in a plan view of the laminated non-woven fabric.
The portion having the interlayer joint is recessed from the second surface side toward the first surface side.
The constituent fibers of the first layer at the interlayer joint maintain the fiber morphology.
The constituent fibers of the second layer at the interlayer joint are melted, and a part of the melted constituent resin enters between the constituent fibers of the first layer and is solidified.
The laminated non-woven fabric is arranged with the second surface facing the wearer's skin side.
An absorbent article in which the absorbent article has a waist circumference corresponding to the wearer's waist and the laminated non-woven fabric is arranged around the waist. The first layer includes a portion of the second layer in which the molten constituent resin has entered and a portion in which the molten constituent resin has not entered, in a portion overlapping the interlayer joint in the thickness direction of the laminated nonwoven fabric. The absorbent article according to claim 1. The second layer partially has a melt-bonded portion in which the heat-sealing fibers are bonded to each other in a plan view of the laminated non-woven fabric.
The absorbent article according to claim 1 or 2, wherein the melt joint portion constitutes the second layer portion of the interlayer joint portion. The absorbent article according to any one of claims 1 to 3, wherein the stretchable region is provided around the waist and the laminated non-woven fabric is arranged in the stretchable region. The absorbent article comprises a liquid-retaining absorber.
The absorbent article according to any one of claims 1 to 4, wherein the laminated non-woven fabric is arranged at a position closer to the wearer's skin than the absorbent body. The absorbent article includes an absorbent body provided with a liquid-retaining absorber and an exterior body fixed to the non-skin contact surface side of the absorbent body.
The exterior body has a ventral exterior body arranged on the ventral side of the wearer and a dorsal exterior body arranged on the dorsal side, and at least the dorsal exterior body is configured to include the laminated non-woven fabric. And
The absorbent article according to any one of claims 1 to 5, wherein the laminated non-woven fabric is arranged with the second surface facing the skin side of the wearer. The absorbent article according to any one of claims 1 to 6, wherein the first layer of the laminated non-woven fabric has a basis weight of 8 g / m ² or more and 40 g / m ² or less. The absorbent article according to any one of claims 1 to 7, wherein the second layer of the laminated non-woven fabric has a basis weight of 3 g / m ² or more and 25 g / m ² or less. The total area of the interlayer joint portion of the laminated nonwoven fabric is 15% or less with respect to the total area of the laminated nonwoven fabric.
The absorbent article according to any one of claims 1 to 8, wherein the area of each of the interlayer joints is 1 mm ² or less. The first layer of the laminated non-woven fabric is mainly composed of non-heat-fused fibers, and at least 50% of the constituent fibers of the first layer are non-heat-fused fibers. The absorbent article according to any one item. The absorbent article according to any one of claims 1 to 10, wherein the non-heat-sealing fiber is a short fiber. The absorbent article according to any one of claims 1 to 11, wherein the first layer has a smaller inter-fiber distance between constituent fibers than the second layer. The absorbent article according to any one of claims 1 to 12, wherein the constituent fibers of the first layer of the laminated nonwoven fabric have a smaller fiber diameter than the constituent fibers of the second layer. Any of claims 1 to 13, wherein the constituent fibers on the second surface side of the first layer of the laminated nonwoven fabric have higher hydrophilicity than the constituent fibers on the first surface side of the first layer. The absorbent article according to item 1. Any of claims 1 to 14, wherein the constituent fibers on the second surface side of the first layer of the laminated nonwoven fabric have a smaller interfiber distance than the constituent fibers on the first surface side of the first layer. Or the absorbent article according to item 1. The constituent fiber on the second surface side of the first layer has a smaller fiber diameter than the constituent fiber on the first surface side of the first layer, according to any one of claims 1 to 15. Absorbent article. The absorbent article according to any one of claims 1 to 16, wherein an elastic member is interposed between a plurality of fiber layers of the laminated nonwoven fabric. The laminated non-woven fabric according to any one of claims 1 to 17, wherein at least one of the first layer and the second layer has elasticity in the width direction orthogonal to the longitudinal direction of the absorbent article. Absorbent article. It has a laminated structure in which a plurality of fiber layers are laminated, has a first surface and a second surface located on the opposite side to the first surface, and the second surface is used toward the skin side of the wearer. It ’s a sweat-absorbing sheet,
It has a hydrophilic first layer forming the first surface and a hydrophobic second layer located on the second surface side of the first layer.
The first layer is composed of non-heat-fused fibers.
The second layer is mainly composed of heat-sealing fibers, which are long fibers.
The sweat-absorbing sheet has a thickness smaller than that of the peripheral portion, and partially has an interlayer joint portion in which the layers constituting the laminated structure are bonded to each other in a plan view of the laminated non-woven fabric.
The portion having the interlayer joint is recessed from the second surface side toward the first surface side.
The constituent fibers of the first layer at the interlayer joint maintain the fiber morphology.
A sweat-absorbing sheet in which the constituent fibers of the second layer at the interlayer joint are melted, and a part of the melted constituent resin enters between the constituent fibers of the first layer and is solidified.

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