JP6864590B2 - Laminated sheet and its manufacturing method and absorbent article - Google Patents

Description

The present invention relates to a laminated sheet, a method for producing the same, and an absorbent article using the laminated sheet.

It is known to use a sheet made of non-woven fabric or pulp as a member of an absorbent article such as a disposable diaper or a sanitary napkin. For example, Patent Document 1 describes a surface material of a sanitary material such as a disposable diaper in which a spunbonded non-woven fabric and thin paper are laminated and arranged so that the surface side of the spunbonded non-woven fabric is in contact with the skin. .. According to Patent Document 1, the body fluid satisfactorily permeates the surface material due to the liquid absorbing power of the pulp fibers constituting the thin paper.

Further, Patent Document 2 describes a spunbonded non-woven fabric having a core-sheath structure and the sheath portion containing fibers of a heat-sealing resin having a melting point lower than that of the core portion, and the non-woven fabric surface is continuously or discontinuously formed by wet papermaking. A composite paper composed of a papermaking layer formed by stacking is described, and the non-woven fabric and the papermaking layer are joined via a low melting point heat-meltable resin in a sheath portion of the spunbonded nonwoven fabric.

Japanese Unexamined Patent Publication No. 05-176954 Japanese Unexamined Patent Publication No. 05-279997

In absorbent articles such as disposable diapers and sanitary napkins, when the excrement liquid such as urine excreted by the wearer diffuses in the direction (horizontal direction) orthogonal to the front-back direction (vertical direction) of the wearer, the excrement liquid is released. There is a risk of so-called lateral leakage that leaks to the outside from around the legs. There is a demand for a sheet-like material that can be used as a constituent member of an absorbent article and is effective in preventing lateral leakage, but a material that can sufficiently meet such a demand has not yet been provided.

Therefore, an object of the present invention is to provide a laminated sheet capable of preferentially diffusing a liquid in a predetermined direction in the plane direction, a method for producing the same, and an absorbent article using the laminated sheet.

The present invention is a laminated sheet in which a cellulosic fiber layer containing cellulosic fibers is partially laminated on a base sheet containing hydrophobic fibers, and the laminated sheet is formed on at least one side of the base sheet. It has a hydrophobic region composed of an exposed portion and a hydrophilic region composed of an exposed portion of the cellulosic fiber layer, and the hydrophilic region extends in one direction, and the hydrophilic region and the hydrophilic region are formed in a direction orthogonal to the extending direction. The hydrophilic region is adjacent to the base sheet, and the base sheet and the cellulosic fiber layer are laminated sheets that are in close contact with each other due to entanglement of fibers.

Further, the present invention is a laminated sheet in which a cellulosic fiber layer containing cellulosic fibers is partially laminated on a base sheet containing hydrophobic fibers, and the laminated sheet is the base sheet on at least one side. It has a hydrophobic region composed of an exposed portion of the cellulosic fiber layer and a hydrophilic region composed of an exposed portion of the cellulosic fiber layer, the hydrophilic region extends in one direction, and the hydrophilic region extends in a direction orthogonal to the extending direction. It is a laminated sheet in which the hydrophobic region is adjacent and the cellulosic fiber layer has a basis weight of ^{more than 0 g / m 2 and} 10 g / m ^{2 or less.}

Further, the present invention is an absorbent article having the above-mentioned laminated sheet of the present invention.
Further, the present invention is obtained through a papermaking step of supplying a slurry containing cellulosic fibers to a base material sheet and partially forming a cellulosic fiber layer on one side of the base material sheet by papermaking, and the papermaking step. This is a method for producing a laminated sheet, which comprises a dividing step of cutting the laminated sheet at a non-forming position of the cellulosic fiber layer and dividing the laminated sheet into a plurality of pieces.

The laminated sheet of the present invention can preferentially diffuse the liquid in a predetermined direction in the surface direction, and therefore can effectively suppress the liquid diffusion in a direction different from the predetermined direction in the surface direction. it can.
According to the method for producing a laminated sheet of the present invention, the laminated sheet of the present invention having such liquid diffusivity can be efficiently produced.
The absorbent article of the present invention is excellent in the effect of preventing lateral leakage of excrement liquid such as urine.

FIG. 1 is a schematic plan view of an embodiment of the laminated sheet of the present invention. FIG. 2 is a schematic cross-sectional view of the cross section taken along line II of FIG. FIG. 3 is a schematic plan view of another embodiment of the laminated sheet of the present invention. FIG. 4 is a plan view schematically showing the skin-facing surface, that is, the surface sheet side of the disposable diaper as an embodiment of the absorbent article of the present invention having the laminated sheet of the present invention, and the elastic members of each part are stretched. It is a plan view in the unfolded state expanded in a plane shape. FIG. 5 is a schematic cross-sectional view of the cross section taken along line II-II of FIG. FIG. 6 is a schematic view showing an apparatus (wet paper machine) that can be used to carry out the method for producing a laminated sheet of the present invention. FIG. 7 is an explanatory diagram of a dividing step in the method for manufacturing a laminated sheet of the present invention.

Hereinafter, the present invention will be described based on the preferred embodiment with reference to the drawings. 1 and 2 show a laminated sheet 1 which is an embodiment of the laminated sheet of the present invention. FIG. 1 is a plan view of one surface 1S1 of both sides 1S1 and 1S2 of the laminated sheet 1, and FIG. 2 is a cross-sectional view taken along the thickness direction of the laminated sheet 1. The laminated sheet 1 has a laminated structure in which the cellulosic fiber layer 3 containing the cellulosic fibers 3F is partially laminated on the base sheet 2 containing the hydrophobic fibers 2F.

The base sheet 2 is preferably composed mainly of hydrophobic fibers 2F, and functions as a hydrophobic layer having relatively low hydrophilicity in the laminated sheet 1. The content of the hydrophobic fiber 2F in the base sheet 2 is preferably at least 50% by mass or more, and the content may be 100% by mass. On the other hand, the cellulosic fiber layer 3 is more hydrophilic than the hydrophobic fiber 2F, and preferably is mainly composed of the cellulosic fiber 3F, which is a hydrophilic fiber having a contact angle with water of less than 90 degrees as measured by the following method. It functions as a hydrophilic layer having a relatively high hydrophilicity in the laminated sheet 1. The content of the cellulosic fiber 3F in the cellulosic fiber layer 3 is preferably at least 50% by mass or more, and the content may be 100% by mass. Therefore, a preferred embodiment of the laminated sheet 1 has a laminated structure in which a hydrophilic layer (cellulosic fiber layer 3) is partially laminated on a hydrophobic layer (base sheet 2).

Whether the fiber is hydrophilic or hydrophobic is determined based on the contact angle with water measured by the following method. If the contact angle is less than 90 degrees, it is hydrophilic, and if it is 90 degrees or more, it is hydrophilic. If so, 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 sheet 1, the hydrophobic fibers 2F constituting the base material sheet 2 preferably have a contact angle with water of 90 degrees or more, and the cellulosic fibers 3F constituting the cellulosic fiber layer 3 are in contact with water. The angle is preferably less than 90 degrees.

<Measurement method of contact angle>
The fibers are taken out from the measurement target (laminated sheet), and the contact angle of water with respect to 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 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 20 picolitres, and the water droplet is dropped directly above the fiber. 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. The contact angle of N = 5 fibers is measured to one digit after the decimal point, and the average value of the measured values at 10 points in total (rounded to the second digit after the decimal point) is defined as the contact angle of the fiber with water. The measurement environment is room temperature 22 ± 2 ° C. and humidity 65 ± 2% RH. The smaller the value of such a contact angle, the higher the hydrophilicity.

The laminated sheet is used as a constituent member of an absorbent article or the like, and when the laminated sheet is taken out and evaluated and measured, the constituent member is fixed to another constituent member by an adhesive, fusion, or the like. If so, remove the fixed portion after removing the adhesive force by blowing cold air from a cold spray or the like within a range that does not affect the contact angle of the fibers. This procedure is common to all measurements herein.

As described above, the laminated sheet 1 of the present embodiment has a laminated structure in which a hydrophilic layer (cellulosic fiber layer 3) is partially laminated on a hydrophobic layer (base sheet 2). In order to determine the presence or absence of such a laminated structure, it is first necessary to determine the presence or absence of a "boundary" of each layer constituting the laminated structure. The boundary between each layer of the laminated sheet is visually discriminated by microscopic observation of the sheet cross section along the vertical thickness direction (direction orthogonal to the plane direction). Due to the shape of the fibers in the cross section of the sheet, the voids between the fibers, the color, the thickness, the presence of a mixture other than the fibers, etc. If, or if there is a gap or boundary line that divides the same direction even if there is no difference in the state in the same direction, that is defined as the boundary of each layer, and it is judged that the laminated sheet has a laminated structure. ..
When it is determined that the laminated sheet has a laminated structure in this way, whether or not the laminated structure includes a hydrophobic layer and a hydrophilic layer depends on the cellulosic fibers (hydrophilic fibers) contained in each layer and other fibers. It can be determined based on the discrimination from the species, the content ratio of each fiber type based on the discrimination, and the like. For the identification of cellulosic fibers contained in each layer and many other fiber types, and for the analysis of the weight and content ratio of the identified fibers, JIS L 1030-1 (Part 1 Fiber Identification), JISL 1030-2 ( The standard of Part 2) Textile product mixing ratio test method) can be used as appropriate. The contact angle of other fiber types other than the cellulosic fiber is measured by the above-mentioned measuring method, and those having a contact angle of 90 degrees or more are designated as hydrophobic fibers. The content ratio of the cellulosic fiber and the hydrophobic fiber in each layer is determined by the above-mentioned JIS method. A layer in which the content ratio of cellulosic fibers is twice or more that of fibers other than cellulose fibers is defined as a "hydrophilic layer", and the content ratio of hydrophobic fibers is twice or more that of cellulosic fibers and other hydrophilic fibers. A layer is referred to as a "hydrophilic layer".

The basis weight of the hydrophilic layer (cellulosic fiber layer) and the hydrophobic layer (base sheet) in the laminated sheet is measured per unit area when each layer can be isolated by delamination with adhesive tape or the like. Ask. If isolation is not possible, the thickness of each layer is measured from a photograph of the cross-sectional area of the laminated sheet, and the ratio is multiplied by the basis weight of the entire laminated sheet to obtain the basis weight of each layer.
The basis weight of the cellulosic fibers and hydrophobic fibers contained in each of the hydrophilic layer and the hydrophobic layer is calculated by multiplying the content ratio of each fiber obtained by the above-mentioned JIS method by the basis weight of each layer. To.

Hydrophobic thermoplastic fibers (heat-fused fibers) can be used as the hydrophobic fibers 2F constituting the base sheet 2. In the base sheet 2, one type of hydrophobic fiber 2F can be used alone or in combination of two or more types. As the material of the hydrophobic fiber 2F, as a hydrophobic thermoplastic resin, for example, polyolefin such as polyethylene and polypropylene; polyester such as polyethylene terephthalate; polyamide such as nylon 6 and nylon 66; polyacrylic acid and polymethacrylic acid alkyl ester, Examples thereof include polyvinyl chloride and polyvinylidene chloride, and one of these can be used alone or in combination of two or more. The hydrophobic fiber 2F may be a single fiber composed of one kind of synthetic resin (thermoplastic resin) or a blend polymer in which two or more kinds of synthetic resins are mixed, or may be a composite fiber. The composite fiber referred to here is a synthetic fiber (thermoplastic fiber) obtained by combining two or more kinds of synthetic resins (thermoplastic resins) having different components with a spinneret and spinning them at the same time. A structure that is continuous in the length direction and is mutually bonded within a single fiber. The form of the composite fiber includes a core sheath type, a side-by-side type, and the like, and is not particularly limited. The contact angle of the hydrophobic fiber 2F with water is preferably 90 degrees or more, more preferably 100 degrees or more.

The form of the base sheet 2 is not particularly limited, and may be, for example, a non-woven fabric, a woven fabric (woven fabric), a knitted fabric, or a paper, or may be a single-layer structure composed of one sheet, or a laminated structure of a plurality of sheets. But it may be. A long-fiber non-woven fabric can be exemplified as an example of the form of the base sheet 2, and in that case, the hydrophobic fiber 2F which is the main component of the long-fiber non-woven fabric is a long fiber. The term "long fiber" as used herein means a fiber having a fiber length of 30 mm or more. In particular, a so-called continuous long fiber having a fiber length of 150 mm or more is 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. In general, long-fiber non-woven fabrics are superior in strength to non-woven fabrics mainly composed of short fibers (short-fiber non-woven fabrics) such as air-through non-woven fabrics. 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.

The content of the hydrophobic fiber 2F in the base sheet 2 is preferably 50% by mass or more, more preferably 50% by mass or more, based on the total mass of the base sheet 2 from the viewpoint of imparting sufficient hydrophobicity to the base sheet 2. It is 70% by mass or more, and for example, an additive such as an oil agent for imparting properties such as slipperiness and hydrophobicity required in the manufacturing stage of the base sheet 2 which is a non-woven fabric, a binder for maintaining strength, and the like. From the viewpoint of containing the above, it is preferably 98% by mass or less, more preferably 90% by mass or less.

As the cellulosic fiber 3F constituting the cellulosic fiber layer 3, fibers mainly composed of cellulose can be used, and for example, those used for various purposes such as sanitary products can be used without particular limitation. More specifically, for example, natural cellulose fiber, marcelled cellulose fiber, dissolved cellulose fiber and cellulose fiber derivative can be mentioned, and one of these can be used alone or in combination of two or more. Examples of the natural cellulose fiber include wood pulp such as softwood pulp and broadleaf pulp; cotton pulp such as cotton linter and cotton lint; non-wood pulp such as straw pulp, bagas pulp and hemp pulp; and waste paper pulp. As is well known, the mercerized cellulose fiber is a cellulose fiber that has been alkali-denatured (so-called mercerized) by a concentrated alkali treatment. Examples of the dissolved cellulose fiber include lyocell (registered trademark), Tencel (registered trademark), Bemberg (registered trademark), viscose rayon, Benlyse (registered trademark) and the like. Examples of the cellulose fiber derivative include carboxymethyl cellulose, carboxyethyl cellulose, TEMPO-catalyzed oxidized cellulose, methyl cellulose, ethyl cellulose and the like. The contact angle of the cellulosic fiber 3F with water is preferably less than 70 degrees, more preferably less than 40 degrees.

The form of the cellulosic fiber layer 3 is not particularly limited, and may be, for example, a non-woven fabric, a woven fabric (woven fabric), a knitted fabric, or paper. The cellulosic fiber layer 3 is typically paper and can be formed by a known wet papermaking method. However, the cellulosic fiber layer 3 does not need to have a thickness and a basis weight sufficient to separate the cellulosic fiber layer 3 from the laminated sheet 1 as, for example, one sheet of paper. That is, the cellulosic fiber layer in the laminated sheet of the present invention can be an ultrathin to low basis weight layer that is difficult to separate by peeling it off from the base sheet.

The content of the cellulosic fiber 3F in the cellulosic fiber layer 3 is preferably 50% by mass or more with respect to the total mass of the cellulosic fiber layer 3 from the viewpoint of imparting sufficient hydrophilicity to the cellulosic fiber layer 3. More preferably, it is 70% by mass or more, and is preferable from the viewpoint of containing a binder component for binding the cellulosic fiber 3F at the production stage of the cellulosic fiber layer 3 which is paper and a chemical such as wet paper strength. It is 98% by mass or less, more preferably 92% by mass or less.

The cellulosic fiber layer 3 can contain fiber components other than the cellulosic fiber 3F, and examples thereof include polyolefin resins such as polyethylene and polypropylene, and polyester resins such as polyethylene terephthalate and polybutylene terephthalate. One of these can be used alone or in combination of two or more. Further, the cellulosic fiber layer 3 can contain components other than the fiber components, and for example, a paper strength enhancer such as polyamine / epichlorohydrin resin, dialdehyde starch, chimen, and carboxymethyl cellulose; Examples include yield improvers, flocculants, pH adjusters, antibacterial agents, deodorants, and flame retardants.

The laminated sheet 1 has a hydrophobic region 4 formed of an exposed portion of the base material sheet 2 and a hydrophilic region 5 formed of an exposed portion of the cellulosic fiber layer 3 on at least one surface. In the laminated sheet 1 shown in FIGS. 1 and 2, the cellulosic fiber layer 3 is laminated only on one surface 1S1 of the laminated sheet 1, and the cellulosic fiber layer 3 is not laminated on the other surface 1S2. The cellulosic fiber layer 3 may be formed only on the other surface 1S2, or may be formed on both sides 1S1 and 1S2. When the cellulosic fiber layer 3 (hydrophilic region 5) is formed on both sides 1S1 and 1S2 of the laminated sheet 1, the arrangement pattern of the hydrophobic region 4 and the hydrophilic region 5 is the same on one surface 1S1 and the other surface 1S2. But it may be different. For example, as will be described later, when the laminated sheet 1 is manufactured by using the wet papermaking method, specifically, a slurry containing the cellulosic fiber 3F is supplied to the base sheet 2 to form the cellulosic fiber layer 3. In the papermaking process, when the water in the slurry is strongly sucked and dehydrated by a suction means such as a suction box, the cellulosic fiber 3F can be penetrated in the thickness direction of the base sheet 2 by the suction force. Hydrophilic regions 4 and hydrophilic regions 5 are present on both sides 1S1 and 1S2 of the manufactured laminated sheet 1, and their arrangement patterns are the same on one surface 1S1 and the other surface 1S2.

The hydrophobic region 4 has a relatively high hydrophobicity (low hydrophilicity) on one surface 1S1 of the laminated sheet 1 because it is formed by the base sheet 2 mainly composed of the hydrophobic fibers 2F. The area. Further, since the hydrophilic region 5 is formed by the cellulosic fiber layer 3 mainly composed of the cellulosic fiber 3F which is a hydrophilic fiber, the hydrophilicity is relatively hydrophilic on one surface 1S1 of the laminated sheet 1. Is a high (low hydrophobicity) region. As described above, the hydrophobic region 4 and the hydrophilic region 5 are mixed on one surface 1S1 of the laminated sheet 1. On the other hand, as shown in FIG. 2, the cellulosic fiber layer 3 does not exist on the other surface 1S2 of the laminated sheet 1, and only the hydrophobic region 4 formed of the exposed portion of the base sheet 2 exists. However, the present invention does not exclude the presence of the cellulosic fiber 3F on the other surface 1S2, and the cellulosic fiber 3F may be present on the other surface 1S2 to the extent that it does not form a layer. As such "a form in which cellulosic fibers are present on one side of the laminated sheet to the extent that no layer is formed", specifically, the laminated sheet 1 manufactured by the wet papermaking method as described above is cellulosic. Examples thereof include a form in which the fiber 3F penetrates in the thickness direction of the base sheet 2.

On one surface 1S1 of the laminated sheet 1, as shown in FIG. 1, the hydrophilic region 5 extends in one direction indicated by X in the drawing and is orthogonal to the extending direction (longitudinal direction of the hydrophilic region 5) X. The hydrophilic region 5 and the hydrophobic region 4 are adjacent to each other in the direction (width direction of the hydrophilic region 5) Y. More specifically, the hydrophilic region 5 has a band shape extending in the direction X in a plan view as shown in FIG. 1, and the length (width) of the direction Y orthogonal to the longitudinal direction X extends over the entire length of the longitudinal direction X. Is constant. A plurality of hydrophilic regions 5 are intermittently arranged at equal intervals in the direction Y on one surface 1S1 of the laminated sheet 1, and a non-arranged portion of the hydrophilic region 5 on one surface 1S1 is a hydrophobic region 4. The plurality of hydrophilic regions 5 have the same width as each other. Further, the hydrophobic region 4 is common to the hydrophilic region 5 in that it has a band shape extending in the direction X in a plan view as shown in FIG. 1 and the length in the direction Y, that is, the width is constant over the entire length in the longitudinal direction. However, the length in the direction Y is shorter and narrower than that of the hydrophilic region 5.

As described above, the hydrophobic region 4 and the hydrophilic region 5 are mixed on one surface 1S1 of the laminated sheet 1, and the hydrophilic region 5 extends in one direction X, and the width direction Y orthogonal to the extending direction X Since the hydrophilic region 5 and the hydrophobic region 4 are adjacent to each other, the diffusibility of the aqueous liquid in the surface direction on one surface 1S1 side is relatively high in the extending direction X of the hydrophilic region 5 (easily diffused). , Width direction Y is relatively low (difficult to diffuse). Therefore, for example, when the laminated sheet 1 is used as a constituent member of a disposable diaper and one surface 1S1 is arranged toward the wearer's skin side (the side that first receives the excretory liquid), the excretory liquid such as urine is discharged. When in contact with one surface 1S1, the excrement liquid is drawn into the laminated sheet 1 (base sheet 2) by the hydrophilic region 5 and is preferentially diffused in the extending direction X and into the width direction Y. Diffusion is suppressed by the hydrophobic region 4 adjacent to the hydrophilic region 5. Therefore, the laminated sheet 1 is absorbed by a disposable diaper or the like so that the extending direction X of the hydrophilic region 5 coincides with the front-back direction of the wearer (the direction extending from the ventral side of the wearer to the dorsal side via the crotch portion). By arranging it on an article, it is possible to effectively prevent so-called lateral leakage in which the excrement liquid leaks to the outside from the leg circumference or the like, and the excretion liquid can quickly permeate the laminated sheet 1 in the thickness direction. The laminated sheet 1 has liquid permeability.

In particular, in the laminated sheet 1, as shown in FIGS. 1 and 2, hydrophobic regions 4 are present on both sides of the width direction Y orthogonal to the extending direction X across the hydrophilic region 5. The diffusibility of the liquid in the width direction Y is very low, and therefore, when the laminated sheet 1 is applied to an absorbent article, lateral leakage can be prevented even more effectively.

Further, in the laminated sheet 1, as shown in FIGS. 1 and 2, the plurality of hydrophilic regions 5 and the plurality of hydrophobic regions 4 are in the width direction Y orthogonal to the extending direction X of the plurality of hydrophilic regions 5. Since they exist alternately, they are excellent in both the property of preferentially diffusing the liquid in one direction X in the plane direction and the property of not diffusing the liquid in the direction Y orthogonal to the one direction X in the plane direction. It is difficult to quickly diffuse the liquid and to diffuse the liquid in the direction Y orthogonal to this. Therefore, when the laminated sheet 1 is applied to an absorbent article, an absorbent article capable of preferentially diffusing excrement liquid such as urine in the front-rear direction of the wearer and reliably preventing lateral leakage can be obtained. Further, since the hydrophilic regions 5 and the hydrophobic regions 4 are alternately present on one surface 1S1 of the laminated sheet 1 in the width direction Y, for example, one surface such as the laminated sheet 1A (see FIG. 3) described later. Compared with the form in which the hydrophilic region 5 occupies most of 1S1, the dry feeling (wetting feeling is reduced) of one surface 1S1 is improved, and the morphological stability of the laminated sheet 1 at the time of water absorption is improved. It is possible to effectively prevent the laminated sheet 1 from sagging or twisting after absorbing water.

Further, in the laminated sheet 1, as shown in FIGS. 1 and 2, hydrophobic regions 4 are provided at both ends in the width direction Y orthogonal to the extending direction X of the hydrophilic region 5 on the surface 1S1 having the hydrophilic region 5. Since it is present, leakage of the liquid from both ends in the width direction Y is unlikely to occur, which makes it possible to more effectively prevent lateral leakage when the laminated sheet 1 is applied to an absorbent article.

From the viewpoint of ensuring that the above-mentioned action and effect are exhibited more reliably, it is preferable to set the dimensions and the like of each part of the laminated sheet 1 as follows.
The width of one hydrophobic region 4, that is, the length W4 (see FIG. 1) in the width direction Y orthogonal to the longitudinal direction (extending direction) X is preferably 1 mm or more, more preferably 10 mm or more, and preferably 80 mm or less. , More preferably 20 mm or less.
The width W5 (see FIG. 1) of one hydrophilic region 5 is preferably 1 mm or more, more preferably 20 mm or more, and preferably 100 mm or less, still more preferably 80 mm or less.
The ratio of the width W4 of one hydrophobic region 4 to the width W5 of one hydrophilic region 5 is preferably 0.05 or more, more preferably 0.5 or more, and more preferably 0.5 or more as the former (W4) / the latter (W5). It is preferably 2 or less, more preferably 1 or less.
On one surface 1S1 of the laminated sheet 1, the number of hydrophilic regions 5 existing in the width direction Y is preferably 1 or more, more preferably 3 or more, and preferably 300 or less, still more preferably 100 or less. .. In FIG. 1, the number of hydrophilic regions 5 existing in the width direction Y is three.

One of the features of the laminated sheet 1 is that the base sheet 2 and the cellulosic fiber layer 3 are in close contact with each other due to the entanglement of fibers. That is, in the laminated adhesion form of the base sheet 2 and the cellulosic fiber layer 3, the hydrophobic fibers 2F of the base sheet 2 and the cellulosic fibers 3F of the cellulosic fiber layer 3 are mainly entangled without an adhesive. Is made by. However, in the laminated adhesion form of both, as a result of the constituent fibers of the base sheet 2 and / or the cellulosic fiber layer 3 having adhesiveness, the fibers are adhered to each other in addition to the entanglement of the fibers. The form is included. The "adhesive" of "no adhesive" mentioned above means an amorphous general adhesive having no fiber shape. Such a laminated adhesion form of the base sheet 2 and the cellulosic fiber layer 3 without an adhesive can be obtained by using a wet papermaking method as described later, and specifically, the base sheet 2 It is obtained by supplying a slurry containing the cellulosic fiber 3F to the cellulosic fiber layer 3 to form the cellulosic fiber layer 3.

In this way, the base sheet 2 and the cellulosic fiber layer 3 are in close contact with each other by entanglement of fibers without an adhesive, so that the liquid permeability at the interface between the base sheet 2 and the cellulosic fiber layer 3 is improved. At the same time, inconveniences of concern in the use of the adhesive, for example, deterioration of water absorption and flexibility of the laminated sheet 1 are prevented. If the base sheet 2 and the cellulosic fiber layer 3 are bonded to each other by an adhesive in the laminated sheet 1, there is a concern that the liquid permeability at the interface between the base sheet 2 and the cellulosic fiber layer 3 may decrease. In addition, it becomes difficult to reduce the basis weight of the cellulosic fiber layer 3. Explaining the latter difficulty of reducing the basis weight, in the method of manufacturing such an adhesive-using type laminated sheet 1, a separately manufactured cellulosic fiber layer 3 in a dry state is laminated on a base sheet 2 in a dry state. When the cellulosic fiber layer 3 used in such a step is also provided with a step of fixing with an adhesive, the cellulosic fiber layer 3 is naturally required to have a certain strength (paper strength) so as not to break during the step. The fiber layer 3 needs to have a basis weight of a certain level or more, and it is difficult to adopt a thin cellulosic fiber layer 3 ^{having a basis weight of, for example, about 1 to 7 g / m 2.} That is, with such a low basis weight, the number of cellulosic fibers is small and it is not possible to form a bond point of the fiber network, so that sufficient strength (paper strength) for handling cannot be obtained. In this respect, as in the present invention, if the laminated sheet 1 has a form in which the base sheet 2 and the cellulosic fiber layer 3 are in close contact with each other by entanglement of fibers without an adhesive, the wet papermaking method is performed as described above. By using this, the laminated sheet 1 can be manufactured without going through the bonding step of the cellulosic fiber layer 3 in a dry state, so that the thin cellulosic fiber layer 3 that is difficult to handle in such a bonding step, that is, It is possible to use a cellulosic fiber layer 3 that is thin or has a small basis weight so that it cannot be formed as a sheet (paper), and as a result, the basis weight of the laminated sheet 1 can be reduced.

The basis weight of the cellulosic fiber layer 3 forming the hydrophilic region 5 is not particularly limited, but even when the basis weight is considerably smaller than the basis weight of the base sheet 2 forming the hydrophobic region 4, the above-mentioned liquid diffusivity and the like can be obtained. The action and effect can be exhibited, and by reducing the basis weight of the cellulosic fiber layer 3, the liquid permeability of the laminated sheet 1 can be improved, and the basis weight of the laminated sheet 1 can be reduced. When the low basis weight laminated sheet 1 is applied to, for example, an absorbent article, it may lead to an improvement in wearing feeling. Considering the above, the cellulosic fiber layer 3 preferably has a lower basis weight than the base sheet 2, and more specifically, the basis weight of the cellulosic fiber layer 3 and the basis weight of the base sheet 2. The ratio to the amount is preferably 0.05 or more, more preferably 0.1 or more, and preferably 0.8 or less, still more preferably 0.4 or less, as the former / the latter.

The basis weight of the base sheet 2 is preferably 5 g / m ² or more, more preferably 8 g / m ² or more, and preferably 25 g / m ² or less, still more preferably 15 g / m ² or less.
The basis weight of the cellulose-based fiber layer 3 is ^{more than 0 g / m 2} , preferably 0.5 g / m ² or more, more preferably 1 g / m ² or more, and preferably 10 g / m ² or less, and further. It is preferably 7 g / m ² or less, more preferably 5 g / m ² or less.

FIG. 3 shows a laminated sheet 1A which is another embodiment of the laminated sheet of the present invention. Other embodiments described later will mainly be described with components different from those of the laminated sheet 1 described above, and similar components will be designated by the same reference numerals and description thereof will be omitted. The description of the laminated sheet 1 is appropriately applied to the components not particularly described.

The laminated sheet 1A shown in FIG. 3 is different from the laminated sheet 1 shown in FIG. 1 in the arrangement pattern of the hydrophobic region 4 and the hydrophilic region 5. That is, in the laminated sheet 1A, as shown in FIG. 3, the cellulosic fiber layer 3 is laminated on the main portion of one surface 1S1 of the laminated sheet 1A except for both ends in one direction (width direction Y) to form a hydrophilic region. 5 is formed, and the hydrophobic region 4 composed of the exposed portion of the base sheet 2 is formed at both ends of the one surface 1S1, that is, at both ends in the direction Y orthogonal to the extending direction X of the hydrophilic region 5 existing in the main portion. Exists. In the laminated sheet 1A, hydrophobic regions 4 exist on both sides of a direction Y orthogonal to the extending direction X with one hydrophilic region 5 in between, and the hydrophilic region 5 on the surface 1S1 having the hydrophilic region 5 The hydrophobic regions 4 are present at both ends in a direction orthogonal to the extending direction X of the above, and by having these configurations, the same effect as that of the laminated sheet 1 can be obtained.

The laminated sheet of the present invention including the above-mentioned laminated sheets 1 and 1A has a feature of preferentially diffusing the liquid in a predetermined one direction (extending direction of the hydrophilic region) in the plane direction. It is suitable for various applications where various features are utilized. In particular, the laminated sheet of the present invention is suitable as a core wrap sheet for covering a liquid-retaining absorbent core in an absorbent article such as a disposable diaper or a sanitary napkin, and more effectively prevents so-called lateral leakage. obtain.

4 and 5 show a deployable disposable diaper 10 which is an embodiment of the absorbent article of the present invention having the laminated sheet of the present invention. The diaper 10 has a vertical direction X corresponding to the front-rear direction of the wearer and a horizontal direction Y orthogonal to the vertical direction X, and has a liquid-retaining absorbent core 14 and the absorbent core 14 wound around the absorbent core 14. A core wrap sheet 15 that covers the skin-facing surface and the non-skin-facing surface of 14 is provided. The core wrap sheet 15 is made of the laminated sheet 1 shown in FIG.

In the present specification, the "skin facing surface" is a surface of the absorbent article or its constituent members (for example, a core wrap sheet) that is directed toward the skin side of the wearer when the absorbent article is worn, that is, relatively of the wearer. The side closer to the skin, the "non-skin facing surface" is the surface of the absorbent article or its constituents that faces the opposite side of the skin when the absorbent article is worn, that is, relatively from the wearer's skin. The distant side. The term "when worn" as used herein means a state in which the normal proper wearing position, that is, the correct wearing position of the absorbent article is maintained.

The diaper 10 has a crotch portion B and a ventral side portion A and a dorsal side portion C extending in the longitudinal direction X from the front and back of the crotch portion B, and the crotch portion B is provided with a liquid-retaining absorber 13. The inseam B is a portion arranged in the crotch portion of the wearer when the diaper 10 is worn, and the ventral side A is the ventral side of the wearer, that is, the vertical direction X, rather than the crotch B when the diaper 10 is worn. The dorsal side portion C is a portion arranged on the front side of the diaper 10 and is arranged on the back side of the wearer, that is, on the rear side of the vertical direction X, rather than the inseam B in the wearing state of the diaper 10.

The diaper 10 has a liquid-permeable front surface sheet 11, a liquid-impermeable or impermeable or water-repellent back surface sheet 12 forming a non-skin facing surface, and a liquid holding agent interposed between the two sheets 11 and 12. A sex absorber 13 is provided, and these are integrated by a known bonding means such as an adhesive. The front surface sheet 11 and the back surface sheet 12 each have a larger size than the absorber 13, and extend outward from the peripheral edge of the absorber 13. The absorber 13 includes an absorbent core 14 and a core wrap sheet 15 that covers the outer surface of the absorbent core 14, more specifically, both the skin-facing surface and the non-skin-facing surface. The absorbent core 14 and the core wrap sheet 15 are joined by a known joining means such as a hot melt type adhesive.

Between the front surface sheet 11 and the back surface sheet 12 on the ventral side A and the dorsal side C, one or a plurality of thread-like or band-shaped elastic members around the waist are fixed in a laterally extended state. One or a plurality of thread-like or band-shaped leg elastic members 22 are fixed between the front surface sheet 11 and the back surface sheet 12 in the left and right leg portions arranged around the wearer's legs in an extended state. Further, a pair of leak-proof cuffs 16 and 16 composed of a liquid-resistant or water-repellent and breathable leak-proof cuff forming sheet are formed on both left and right sides of the diaper 10 on the skin-facing surface along the vertical direction X. It is provided. One or more thread-shaped elastic members 23 for forming a leak-proof cuff are arranged in the vicinity of the free end of each leak-proof cuff 16 in an extended state in the vertical direction X. When the diaper 10 is worn, the leak-proof cuff 16 is used by the wearer, starting from a joint between the leak-proof cuff forming sheet constituting the leak-proof cuff 16 and another constituent member (for example, the back surface sheet 12). Stand up toward the skin. Further, a pair of fastener tapes 17 and 17 are provided on both side edges of the back side portion C of the diaper 10 along the vertical direction X, and further, a non-skin facing surface (back surface sheet 12) of the ventral side portion A of the diaper 10 is provided. The non-skin facing surface) is provided with a fastening region 18 made of a female member of the mechanical hook-and-loop fastener, and a fastening portion made of a male member of the mechanical hook-and-loop fastener of the fastening tape 17 is fastened. It can be stopped in the area 18. As the constituent members other than the core wrap sheet 15, such as the front surface sheet 11, the back surface sheet 12, the absorbent core 14, and the leakage-proof cuff 16, those normally used in this type of absorbent article shall be used without particular limitation. Can be done. The absorbent core 14 is typically composed of a deposit of a core-forming material containing an absorbent material, wherein the absorbent material is, for example, wood pulp, a hydrophilic fiber treated with a hydrophilic agent, or the like. Examples include fibers and water-absorbent polymer particles.

Explaining the absorber 13 which is one of the main features of the diaper 10, the core wrap sheet 15 constituting the absorber 13 is composed of one laminated sheet 1, and as shown in FIG. 5, the absorbent core 14 On the non-skin facing surface side, more specifically, between the absorbent core 14 and the back surface sheet 12, both side edges of one core wrap sheet 15 (laminated sheet 1) along the vertical direction X overlap each other. The side edge overlapping portion 20 is formed. The core wrap sheet 15 is arranged on the diaper 10 so that the extending direction X of the hydrophilic region 5 in the laminated sheet 1 constituting the core wrap sheet 15 coincides with the vertical direction X of the diaper 10. Therefore, the width direction Y (see FIG. 1) orthogonal to the extending direction X in the laminated sheet 1 coincides with the lateral direction Y of the diaper 10.

As shown in FIG. 4, the absorptive core 14 extends longitudinally X from the ventral side A through the crotch B to the dorsal side C and thus covers the outer surface of the absorptive core 14. Similarly, the hydrophobic region 4 and the hydrophilic region 5 of the laminated sheet 1 constituting the core wrap sheet 15 extend in the longitudinal direction X from the ventral side portion A through the crotch portion B to the dorsal side portion C. Further, in the laminated sheet 1 constituting the core wrap sheet 15, as shown in FIG. 4, the plurality of hydrophilic regions 5 and the plurality of hydrophobic regions 4 are in the lateral direction orthogonal to their extending direction, that is, the vertical direction X. It exists alternately in Y.

The sheet side edge overlapping portion 20 is formed at least on the inseam B on the non-skin facing surface side of the absorbent core 14. In the diaper 10, the seat side edge overlapping portion 20 extends in the longitudinal direction X from the ventral side A through the crotch B to the dorsal side C, and as shown in FIG. 5, the absorber 13 It is located in the center of the lateral direction Y.

The edge overlapping portion of the core wrap sheet, such as the sheet side edge overlapping portion 20, has been conventionally used in this type of absorbent article and is known. In general, the overlapping end portion of the core wrap sheet is formed in the lateral central portion of the crotch where the amount of excrement liquid such as urine is relatively large in the absorbent article, so that the excrement liquid is formed at the edge of the core wrap sheet. It is easy to concentrate on the overlapping part, and if the wearer's body pressure or the like is applied to the overlapping part at the end of the core wrap sheet in such a state, there is a problem that the excrement liquid exudes from there and leaks to the outside.

On the other hand, in the diaper 10, the laminated sheet 1 having the hydrophobic region 4 is adopted as the core wrap sheet 15, and the arrangement of the hydrophobic region 4 in the sheet side edge overlapping portion 20 is devised. I am trying to solve it. That is, in the diaper 10, the sheet side edge overlapping portion 20 has a hydrophobic region 4 on one of both side edges along the vertical direction X of the laminated sheet 1 constituting the core wrap sheet 15 and a hydrophobic region 4 on the other. There are overlapping hydrophobic region overlaps (not shown). The hydrophobic region overlapping portion has a laminated structure of the base sheet 2 forming the hydrophobic region 4, and the cellulosic fiber layer 3 forming the hydrophilic region 5 is not arranged in the laminated structure. In this way, the presence of the hydrophobic region overlapping portion in the sheet side edge overlapping portion 20 makes it difficult for the excretory liquid to be concentrated in the sheet side edge overlapping portion 20, so that the sheet side edge overlapping portion overlaps. The inconvenience that the excrement liquid exudes from the part 20 and leaks to the outside from the back sheet 12 is effectively prevented.

In order to solve the above problem, at least a part of the sheet side edge overlapping portion 20 may be the hydrophobic region overlapping portion. For example, in the sheet side edge overlapping portion 20, in addition to the hydrophobic region overlapping portion, the hydrophilic region 5 in one of the side edge portions along the vertical direction X of the laminated sheet 1 constituting the core wrap sheet 15 and the other. There may be a hydrophilic region overlapping portion (not shown) that overlaps the hydrophilic region 5, in which case the hydrophobic region overlapping portion and the hydrophilic region overlapping portion may be adjacent to each other in the lateral direction Y. The hydrophobic region overlapping portion is formed by laminating only the hydrophobic region 4 (base sheet 2), but the hydrophilic region overlapping portion is formed by the base sheet 2 (hydrophobic region 4) and the cellulosic fiber layer 3 (base sheet 2). Since the laminated structure with the hydrophilic region 5) is laminated, both regions 4 and 5 coexist.

However, from the viewpoint of more reliably preventing the problem, it is preferable that the ratio of the hydrophobic region overlapping portion in the sheet side edge overlapping portion 20 is high, and the entire sheet side edge overlapping portion 20 is the hydrophobic region overlapping portion 20. It is more preferable that the hydrophilic region overlapping portion does not exist in the portion, that is, the sheet side edge portion overlapping portion 20. For example, when the laminated sheet 1 (see FIG. 1) or the laminated sheet 1A (see FIG. 3) is used as the core wrap sheet 15, one of the hydrophobic edges of both sheets 1 and 1A along the vertical direction X is hydrophobic. By superimposing only the region 4 and the other hydrophobic region 4, the seat side edge overlapping portion 20 having only the hydrophobic region overlapping portion and having no hydrophilic region overlapping portion can be obtained.

Hereinafter, the method for producing a laminated sheet of the present invention will be described by taking the method for producing a laminated sheet 1 as an example. FIG. 6 shows a wet paper machine 30 that can be used to manufacture the laminated sheet of the present invention. The wet paper machine 30 includes a paper machine 31, a slurry supply device 32, a press roll 35, and a Yankee dryer 37. The basic configuration of the wet paper machine 30 is the same as that of a known wet paper machine.

The method for producing the laminated sheet 1 includes a papermaking step in which a slurry containing a cellulosic fiber 3F is supplied to the base sheet 2 and the cellulosic fiber layer 3 is partially formed on one side of the base sheet 2 by papermaking. It has a dividing step of cutting the laminated sheet 1 obtained through the papermaking step at a predetermined position and dividing the laminated sheet 1 into a plurality of pieces. As described above, the base material sheet 2 used in such a manufacturing method is a sheet-like material mainly composed of hydrophobic fibers (for example, all of the constituent fibers are hydrophobic fibers), and is, for example, a spunbonded non-woven fabric or the like. It is a long fiber non-woven fabric. More specifically, the method for producing the laminated sheet 1 includes a dehydration step of dehydrating the molded sheet 40 obtained in the papermaking step and a drying step of drying the dehydrated molded sheet 40 to obtain the laminated sheet 1. And a winding step of winding the obtained laminated sheet 1. The molded sheet 40 obtained in the papermaking step is a laminated sheet 1 in a wet state, and the laminated sheet 1 in a dry state is obtained by dehydrating and drying the laminated sheet 40.

In the wet paper machine 30, as shown in FIG. 6, first, the base sheet 2 wound in a roll shape is continuously unwound, and the surface to be formed of the hydrophilic region 5 (one surface 1S1 of the laminated sheet 1). The surface) is placed on the papermaking net 31 with the surface facing upward and conveyed in one direction. Then, the slurry containing the cellulosic fiber 3F is supplied from the slurry supply device 32 to the upper surface of the base sheet 2 on the papermaking net 31 during the transportation, that is, the planned formation surface of the hydrophilic region 5, and the base sheet 2 The cellulosic fiber layer 3 is partially formed on the upper surface (papermaking step). The water in the supplied slurry sequentially permeates the base sheet 2 and the papermaking net 31 and flows down from below the papermaking net 31, and the fiber components such as the cellulosic fiber 3F in the slurry are the base material sheet 2. The cellulosic fiber layer 3 containing the cellulosic fiber 3F is partially laminated on one side of the papermaking net 31 by being entangled with the constituent fibers (hydrophobic fiber 2F) of the above and staying on the base sheet 2. A molded sheet 40 (laminated sheet 1 in a wet state) having the above-mentioned structure is formed.

In the papermaking step, the slurry containing the cellulosic fiber 3F is supplied to the entire planned formation surface of the hydrophilic region 5 of the base sheet 2, but the cellulosic fiber layer 3 is formed on the planned formation surface. Is only part of. This is because the papermaking net 31 that supports the base sheet 2 from the side opposite to the supply side of the slurry is configured so that the liquid permeability is partially different. That is, the papermaking net 31 has a highly permeable portion having a relatively high liquid permeability and a low permeable portion having a relatively low liquid permeability or zero liquid permeability, and both of these permeable portions are in the papermaking process. It is arranged corresponding to the arrangement pattern of the hydrophobic region 4 and the hydrophilic region 5 in the molded sheet 40 (laminated sheet 1 in a wet state) which is the production object in the above. The highly permeable portion has extremely high water permeability in the slurry, and due to this, in the papermaking process, fiber components in the slurry are deposited on the portion of the base sheet 2 that overlaps with the highly permeable portion, and the slurry is based on cellulose. The fiber layer 3 (hydrophilic region 5) is formed. On the other hand, since the low-permeability portion has extremely low water permeability in the slurry or does not permeate water at all, in the papermaking process, the fiber component in the slurry is located at the portion of the base sheet 2 that overlaps with the low-permeability portion. Does not accumulate, and the base sheet 2 remains exposed and becomes a hydrophobic region 4. The highly permeable portion can be referred to as a hydrophilic region forming portion, and the low permeable portion can be referred to as a hydrophobic region forming portion. In the papermaking net 31, the plurality of low-permeability portions (hydrophilic region forming portions) and high-permeability portions (hydrophilic region forming portions) extend in the transport direction (MD; Machine Direction) of the base sheet 2, respectively. , Both transmissive portions are alternately present in the direction orthogonal to the MD (CD; Cross machine Direction), and the low transmissive portions are present at both ends of the CD. The liquid permeability of the papermaking net 31 can be adjusted by adjusting the size of the mesh through which the liquid permeates, the number of meshes per unit area, and the like. Liquid permeability can be reduced by reducing the size of the mesh and reducing the number of meshes per unit area, or by sealing with a non-liquid permeable plate, adhesive tape, or the like. For example, when a non-liquid permeable plate (sealing) is arranged on a part of the papermaking net 31, the arrangement portion of the plate becomes the low permeable portion.

In the wet paper machine 30, as shown in FIG. 6, a suction box 33 is arranged on the side opposite to the slurry supply device 32 side with the paper making net 31 interposed therebetween. When the cellulosic fiber layer 3 is formed on the material sheet 2, the suction box 33 sucks and dehydrates the water in the slurry. By increasing the suction force in suction and dehydration by the suction box 33, the cellulosic fibers 3F in the slurry can be unevenly distributed on the papermaking net 31 side, and depending on the suction force and the basis weight of the base sheet 2, the cellulosic fibers can be distributed. The system fiber 3F can be penetrated in the thickness direction of the base sheet 2. Therefore, when the hydrophilic regions 5 are formed on both sides 1S1 and 1S2 of the laminated sheet 1, the papermaking step is a step of sucking and dehydrating the moisture in the slurry containing the cellulosic fibers 3F supplied to the base sheet 2. It is preferable to have.

The molded sheet 40 obtained in the papermaking step is delivered from the papermaking net 31 to the belt conveyor 34 and conveyed, and is dehydrated to a predetermined water content during the transfer (dehydration step). In the wet paper machine 30, as shown in FIG. 6, the dehydration step is carried out by passing the molded sheet 40 between the pair of press rolls 35 while applying pressure. In addition to such a dehydration method, a method of dehydrating by suction, a method of blowing pressurized air to dehydrate, and the like can be mentioned.

The molded sheet 40 that has undergone the dehydration step is conveyed to the vicinity of the Yankee dryer 37 by the belt conveyor 36, and is dried by being brought into contact with the surface of the Yankee dryer 37 (drying step). The drying method in the drying step is not limited to the method using such a Yankee dryer, and can be appropriately selected according to the thickness and water content of the molded sheet 40, the water content after drying, and the like. For example, heating. Drying methods such as contact with a structure (heating element), spraying of heated air or steam (superheated steam), vacuum drying, electromagnetic wave heating, and energization heating can be mentioned. Further, in the form shown in FIG. 6, dehydration and drying of the molded sheet 40 are performed separately, but both steps can be simultaneously performed by appropriately combining the above-mentioned dehydration method and drying method. By dehydrating and drying the molded sheet 40 in this way, the laminated sheet 1 can be obtained. In the obtained laminated sheet 1, a plurality of hydrophobic regions 4 and hydrophilic regions 5 extend in the transport direction (MD) of the base sheet 2, and both regions 4 and 5 are orthogonal to the MD (in the direction (MD)). CD) alternates, and hydrophobic regions 4 are present at both ends of the CD. That is, the extending direction X of the hydrophobic region 4 and the hydrophilic region 5 coincides with MD, and the width direction Y orthogonal to the extending direction X coincides with CD.

The continuous strip-shaped laminated sheet 1 thus obtained is wound by a winding roll 38 to form a roll-shaped wound product as shown in FIG. 7 (winding step). Before winding the laminated sheet 1 into a roll, the laminated sheet 1 may be subjected to a post-treatment such as a crepe treatment, if necessary.

The laminated sheet 1 formed into a roll-shaped wound material as shown in FIG. 7 is cut at the cutting position indicated by the reference numeral CL in FIG. 7 and divided into a plurality of parts (division step). This division step is a so-called slit processing, which is a step of continuously cutting (slitting) a long laminated sheet having a large width with a predetermined width. One of the main features of the method for producing a laminated sheet of the present invention is that the cutting position of the laminated sheet 1 in the dividing step is a non-forming position of the cellulosic fiber layer 3 (hydrophilic region 5). In the form shown in FIG. 7, the non-formed position of the cellulosic fiber layer 3 in the laminated sheet 1, that is, the hydrophobic region 4 which is the exposed portion of the base sheet 2 is set as the cutting position CL.

The cellulose-based fiber layer 3, which is mainly made of cellulose-based fibers and is typically made by a wet papermaking method, has a plane direction as compared with a base sheet 2 which is typically a long-fiber non-woven fabric. Since the interfiber bond is weak and the fixing force to the base sheet 2 is not so strong, when the laminated sheet 1 is cut at the formation position of the cellulose fiber layer 3, paper dust is likely to be generated, and the paper generated by the cutting is likely to be generated. The powder may contaminate the laminated sheet 1 and the cutting device. In particular, when the cellulosic fiber layer 3 has a low basis weight, if the laminated sheet 1 is cut by the low basis weight cellulose fiber layer 3, a large amount of paper dust is likely to be generated. Therefore, in the present invention, as shown in FIG. 7, the non-formed position of the cellulosic fiber layer 3, that is, the hydrophobic region 5 which is the exposed portion of the base sheet 2 is set as the cutting position CL, and the laminated sheet 1 is set at this cutting position CL. To disconnect. In the form shown in FIG. 7, the laminated sheet 1 is wound and then cut (slit) at the cutting position CL (non-forming position of the cellulosic fiber layer 3), but before the laminated sheet 1 is wound. It may be cut and the cut laminated sheet 1 may be wound up to form a wound product.

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. The absorbable article of the present invention is not limited to the deployable disposable diaper as in the above embodiment, and broadly includes articles used for absorbing body fluids (urine, loose stool, menstrual blood, sweat, etc.) discharged from the human body. Pants-type disposable diapers, sanitary napkins, sanitary shorts, incontinence pads, etc. are also included. The following additional notes will be further disclosed with respect to the above-described embodiments of the present invention.

<1>
A laminated sheet in which a cellulosic fiber layer containing cellulosic fibers is partially laminated on a base sheet containing hydrophobic fibers.
The laminated sheet has a hydrophobic region formed of an exposed portion of the base material sheet and a hydrophilic region formed of an exposed portion of the cellulosic fiber layer on at least one surface, and the hydrophilic region extends in one direction. The hydrophilic region and the hydrophobic region are adjacent to each other in a direction orthogonal to the extending direction.
A laminated sheet in which the base material sheet and the cellulosic fiber layer are in close contact with each other due to entanglement of fibers.
<2>
The laminated sheet according to <1>, wherein the cellulosic fiber layer has a basis weight of ^{more than 0 g / m 2 and} 10 g / m ^{2 or less.}

<3>
A laminated sheet in which a cellulosic fiber layer containing cellulosic fibers is partially laminated on a base sheet containing hydrophobic fibers.
The laminated sheet has a hydrophobic region formed of an exposed portion of the base material sheet and a hydrophilic region formed of an exposed portion of the cellulosic fiber layer on at least one surface, and the hydrophilic region extends in one direction. The hydrophilic region and the hydrophobic region are adjacent to each other in a direction orthogonal to the extending direction.
A laminated sheet in which the basis weight of the cellulosic fiber layer is ^{more than 0 g / m 2 and} 10 g / m ^{2 or less.}
<4>
The laminated sheet according to <3>, wherein the base material sheet and the cellulosic fiber layer are in close contact with each other due to entanglement of fibers.

<5>
The laminated sheet according to any one of <1> to <4>, wherein the hydrophobic regions are present on both sides of the hydrophilic region in a direction orthogonal to the extending direction thereof.
<6>
The laminated sheet according to any one of <1> to <5>, wherein the plurality of the hydrophilic regions and the plurality of the hydrophobic regions are alternately present in a direction orthogonal to the extending direction of the plurality of hydrophilic regions. ..
<7>
The item according to any one of <1> to <6>, wherein the hydrophobic regions are present at both ends of the laminated sheet in a direction orthogonal to the extending direction of the hydrophilic regions on the surface having the hydrophilic regions. Laminated sheet.
<8>
The laminated sheet according to any one of <1> to <7>, wherein the content of the cellulosic fiber in the cellulosic fiber layer may be 50% by mass or more and 100% by mass.
<9>
The item according to any one of <1> to <8>, wherein the hydrophobic fiber has a contact angle with water of 90 degrees or more, and the hydrophilic fiber has a contact angle with water of less than 90 degrees. Laminated sheet.
<10>
The laminated sheet according to any one of <1> to <9>, wherein the hydrophobic fiber has a contact angle with water of 100 degrees or more.
<11>
The laminated sheet according to any one of <1> to <10>, wherein the contact angle of the cellulosic fiber with water is less than 70 degrees, preferably less than 40 degrees.

<12>
The hydrophobic fiber is composed of a hydrophobic thermoplastic resin.
The thermoplastic resin is one or more selected from the group consisting of polyolefin, polyester, polyamide, polyacrylic acid, polymethacrylic acid alkyl ester, polyvinyl chloride and polyvinylidene chloride.
The laminated sheet according to any one of <1> to <11>, wherein the polyolefin contains polyethylene and polypropylene, the polyester contains polyethylene terephthalate, and the polyamide contains nylon 6 and nylon 66.
<13>
The laminated sheet according to any one of <1> to <12>, wherein the base material sheet is a long fiber non-woven fabric.
<14>
The laminated sheet according to any one of <1> to <13>, wherein the cellulosic fiber layer is laminated only on one surface of the laminated sheet.
<15>
The laminated sheet according to any one of <1> to <14>, wherein the hydrophobic region has a shorter length in a direction orthogonal to the extending direction than the hydrophilic region.
<16>
The laminated sheet according to any one of <1> to <15>, wherein the base material sheet and the cellulosic fiber layer are adhered to each other without an adhesive.
<17>
The laminated sheet according to any one of <1> to <16>, wherein the cellulosic fiber layer is so thin that it cannot be formed as paper by itself or has a small basis weight.

<18>
The ratio of the basis weight of the cellulosic fiber layer to the basis weight of the base material sheet is 0.05 or more and 0.8 or less, preferably 0.1 or more, and preferably 0. 4. The laminated sheet according to any one of <1> to <17>, which is 4 or less.
<19>
In any one of the above <1> to <18>, the ratio of the basis weight of the cellulosic fiber layer to the basis weight of the base material sheet is 0.1 or more and 0.4 or less as the former / the latter. The laminated sheet described.
<20>
The basis weight of the cellulosic fiber layer is 0.5 g / m ² or more and 7 g / m ² or less, preferably 1 g / m ² or more, and preferably 5 g / m ² or less. 19> The laminated sheet according to any one item.
<21>
The laminated sheet according to any one of <1> to <20>, wherein the cellulosic fiber layer has a basis weight of 1 g / m ² or more and 5 g / m ^{2 or less.}

<22>
An absorbent article having the laminated sheet according to any one of <1> to <21>.
<23>
It has a vertical direction corresponding to the front-back direction of the wearer and a horizontal direction orthogonal to the vertical direction, and has a liquid-retaining absorbent core and a skin-facing surface and a non-skin-facing surface of the absorbent core wrapped around the absorbent core. A core wrap sheet that covers the surface is provided, and on the non-skin facing surface side of the absorbent core, both side edges of the core wrap sheet along the vertical direction overlap to form a sheet side edge overlapping portion. Orthogonal
The core wrap sheet is the laminated sheet, and the extending direction of the hydrophilic region in the laminated sheet coincides with the vertical direction.
The absorption according to <22>, wherein a hydrophobic region overlapping portion is present in the sheet side edge overlapping portion where the hydrophobic region on one of the side edge portions of the core wrap sheet and the hydrophobic region on the other overlap. Sex goods.
<24>
The absorbent article according to <22> or <23>, wherein all of the sheet side edge overlapping portions are the hydrophobic region overlapping portions.

<25>
The method for manufacturing a laminated sheet according to any one of <1> to <21>.
A papermaking process in which a slurry containing the cellulosic fibers is supplied to the base sheet and a cellulose fiber layer is partially formed on one side of the base sheet by papermaking.
A method for producing a laminated sheet, which comprises a dividing step of cutting the laminated sheet obtained through the papermaking step at a non-forming position of the cellulosic fiber layer and dividing the laminated sheet into a plurality of layers.
<26>
A papermaking process in which a slurry containing cellulosic fibers is supplied to a base sheet and a cellulosic fiber layer is partially formed on one side of the base sheet by papermaking.
A method for producing a laminated sheet, which comprises a dividing step of cutting the laminated sheet obtained through the papermaking step at a non-forming position of the cellulosic fiber layer and dividing the laminated sheet into a plurality of layers.
<27>
In the papermaking step, the water in the slurry supplied to the substrate sheet is suction-dehydrated by suction means, and the cellulosic fibers contained in the slurry are penetrated in the thickness direction of the substrate sheet. > Or <26>. The method for producing a laminated sheet.
<28>
In the papermaking process, the slurry is supplied from the side opposite to the papermaking net to the base sheet in a state of being placed on the papermaking net.
The papermaking net is configured so that the liquid permeability is partially different, and a plurality of portions having different liquid permeability are the hydrophobic region and the hydrophilic region in the laminated sheet obtained through the papermaking step. The method for manufacturing a laminated sheet according to any one of <25> to <27>, which is arranged corresponding to the arrangement pattern.
<29>
In the laminated sheet obtained through the manufacturing step, the plurality of the hydrophobic regions and the hydrophilic regions extend in the transport direction (MD) of the base material sheet, and both regions 4 and 5 are MD. The method for producing a laminated sheet according to any one of <25> to <28>, wherein the hydrophobic regions are present at both ends of the CD, which are alternately present in the direction (CD) orthogonal to the CD.
<30>
The basis weight of the cellulosic fiber layer in the laminated sheet obtained through the fabrication step in a dry state is ^{more than 0 g / m 2 and} 10 g / m ² or less, preferably 0.5 g / m ² or more, and further. The method for producing a laminated sheet according to any one of <25> to <29>, preferably 1 g / m ² or more, preferably 7 g / m ² or less, and more preferably 5 g / m ^{2 or less.} ..
<31>
Any one of <25> to <30>, wherein the cellulosic fiber layer in the laminated sheet obtained through the papermaking step has a basis weight of 1 g / m ² or more and 5 g / m ^{2 or less in a dry state.} The method for manufacturing a laminated sheet according to the section.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to such Examples.

[Examples 1 to 3]
Laminated sheets were manufactured using a general-purpose wet paper machine. Specifically, cellulosic fibers (fiber concentration 0.1% by mass) and wet paper strength agent (trade name "WS-4030", manufactured by Seikou PMC Co., Ltd.) 0.5% by mass (against cellulosic fibers). Was uniformly dispersed in water to prepare a slurry (paper material). The cellulosic fiber was fibrillated by a beating machine and had a freeness of 650 mL. Next, a base sheet having a width (CD length) of 300 mm is placed on a wire mesh papermaking wire having a wire opening diameter of 90 μm (166 mesh), and the slurry is sprayed on the upper surface of the base sheet to form the base. By partially forming a cellulosic fiber layer having a predetermined basis weight on one surface of the material sheet, a hydrophobic region composed of an exposed portion of the base material sheet and a hydrophilic region composed of an exposed portion of the cellulose fiber layer can be formed. A molded sheet having the above was obtained. This molded sheet was dehydrated using a suction box and a press roll, and further pressed against the surface of a Yankee dryer to be dried to obtain a laminated sheet having a width of 260 mm.
In the laminated sheets of Examples 1 to 3 thus obtained, the hydrophobic region and the hydrophilic region respectively extend to the MD, both regions are alternately present in the CD, and the hydrophobic regions are present at both ends of the CD. Exists. The arrangement pattern of both regions in the laminated sheets of Examples 1 to 3 is a stripe shape similar to that of the laminated sheet 1 shown in FIG. 1, and is different from that of the laminated sheet 1 in terms of the number of both regions and the length (width) of the CD. different.

In the production of the laminated sheets of Examples 1 to 3, softwood bleached kraft pulp (NBKP) (trade name "Caribbean", manufactured by Caliboo Pump and Paper) was used as the cellulosic fiber. As the base material sheet, a spunbonded non-woven fabric (long-fiber non-woven fabric) having ^{a basis weight of 9 g / m 2} and having hydrophobic fibers made of polypropylene resin as constituent fibers was used. As the wire mesh papermaking wire, a wire whose liquid permeability was adjusted according to the patterns of the hydrophobic region and the hydrophilic region was used. The papermaking speed during wet papermaking was 10 m / min.

[Reference example]
The base sheet (spun-bonded non-woven fabric) constituting the laminated sheets of Examples 1 to 3 was used as a reference example as it was.

[Comparative example]
A laminated sheet was produced in the same manner as in Examples 1 to 3 except that a cellulosic fiber layer was formed over the entire surface of one surface of the base sheet and the entire surface of the base sheet was made into a hydrophilic region, which was used as a comparative example.

[Evaluation test 1]
For each example, reference example, and comparative example, the lateral leakage prevention property was evaluated by the following method. The results are shown in Table 1 below.

<Evaluation method for lateral leakage prevention>
A 15 cm square square shape is cut out from the sheet to be evaluated and used as a sample. The sample is fixed on a flat acrylic plate with no unevenness in a stretched state using adhesive tape. If a cellulosic fiber layer is formed on the surface of the sample, the sample is fixed to the plate with the formation surface of the cellulosic fiber layer facing up. 10 g of artificial urine is dropped onto the sample from directly above the center of the sample over 3 seconds, and within 20 seconds after the completion of the dropping, the artificial urine is not absorbed by the sample and overflows and diffuses on the surface. Observe. At this time, the maximum length (horizontal length, direction orthogonal to the extending direction of the hydrophilic fiber layer) of the artificial urine diffusion portion (liquid diffusion portion) on the surface of the sample is orthogonal to the maximum length direction at that moment. The length (vertical length) in the direction to be used is measured, and the ratio (aspect ratio; vertical length / horizontal length) is calculated. The larger the aspect ratio, the more preferentially the liquid is diffused in a predetermined direction (the maximum length direction) in the plane direction of the sample, and the liquid is less likely to be diffused in the direction orthogonal to the one direction, so that the liquid is prevented from lateral leakage. It is judged to be excellent and highly evaluated.
For example, as in Examples 1 to 3, when the cellulosic fiber layer extends in one direction on the dropping surface (liquid receiving surface) of artificial urine in the sample, it is artificial in the extending direction of the cellulosic fiber layer. Since urine preferentially diffuses to form an elliptical liquid diffusion portion in a plan view, the length of the liquid diffusion portion in the extending direction becomes the vertically long portion, which is orthogonal to the extending direction of the liquid diffusion portion. The length in the width direction is the horizontal length.
The composition of the artificial urine is as follows; urea 1.94% by mass, sodium 0.7954% by mass, magnesium sulfate (pentahydrate) 0.11058% by mass, calcium chloride (dihydrate) 0. 06208% by mass, potassium sulfate 0.19788% by mass, polyoxyethylene lauryl ether 0.0035% by mass and deionized water (remaining amount).

As shown in Table 1, in each example, since the hydrophilic region and the hydrophobic region are mixed in a predetermined pattern on the liquid receiving surface, the aspect ratio of the liquid diffusion portion greatly exceeds 1, that is, the cellulosic fiber. While the liquid was preferentially diffused in the extending direction of the layer (hydrophilic region), it was difficult to diffuse the liquid in the direction orthogonal to the extending direction. Therefore, when the laminated sheet of each embodiment is applied to an absorbent article such as a disposable diaper so that the extending direction of the hydrophilic region in the laminated sheet coincides with the front-back direction (longitudinal direction) of the wearer, It is inferred that lateral leakage is effectively prevented.
On the other hand, in the reference example and the comparative example, since only one of the hydrophilic region and the hydrophobic region exists on the liquid receiving surface, the aspect ratio of the liquid diffusion portion is close to 1, and the liquid is preferentially given in a predetermined direction. The ability to diffuse was poor.

[Test Examples 1 to 3]
According to the method for producing laminated sheets of Examples 1 to 3, using the same raw materials as the production method, a cellulosic fiber layer (hydrophilic region) having a predetermined basis weight is used over one surface (hydrophobic region) of the base sheet. Was formed to produce a laminated sheet. Two 5 cm square square shapes were cut out from the produced laminated sheet, and the two sheets were overlapped so that the cellulosic fiber layer was the upper layer and the base sheet was the lower layer to prepare a sample (Test Examples 2 and 3). Separately, two 5 cm square square shapes were cut out from the base sheet and superposed to prepare a sample (Test Example 1).
[Evaluation test 2]
For each reference example, the exudation prevention property was evaluated by the following method. The results are shown in Table 2 below. The purpose of the exudation prevention property is to evaluate the degree of exudation of the liquid from the above-mentioned sheet side edge overlapping portion when the sample is used as a core wrap sheet in an absorbent article.

<Evaluation method for exudation prevention>
A pulp sheet with a basis weight of 200 g / m ² is laid on a laboratory table, and the sample is placed on the pulp sheet in a spread state. An acrylic cylinder having a cylinder inner diameter of 25 mmφ and a cylinder height of 50 mm is placed on the sample. Acrylic injection plates integrally molded so that the portion is located on the injection opening of 10 mmφ are placed on top of each other so that the injection holes are located in the center of the sample, and an appropriate weight plate is placed on the plate. Adjust so that the load (including the liquid injection plate itself) is 1 kPa. 10 mL of physiological saline (0.9 mass% sodium chloride aqueous solution) is poured into the cylinder of the injection plate at once, and from the moment the pouring is completed until the physiological saline in the cylinder disappears and the surface of the sample is exposed. Measure the time (seconds / 10 mL) and use this as the liquid permeation time. Each sample is measured three times, and the average value is taken as the liquid permeation time of the sample. The longer the liquid permeation time, the less likely it is that the liquid will seep out from the overlapping portion of the side edge of the sheet when used as a core wrap sheet, which is highly evaluated.

As shown in Table 2, Test Example 1 in which two base sheets (hydrophobic regions) are laminated is a test in which two laminated sheets in which a cellulosic fiber layer (hydrophilic region) is laminated on the entire surface of the base sheet are laminated. Compared with Examples 2 and 3, the liquid permeation time was long and the liquid oozing prevention property was excellent. Therefore, when a laminated sheet in which a cellulosic fiber layer is partially laminated on one surface of a base sheet is used as a core wrap sheet in an absorbent article, the sheet side edge overlap of the core wrap sheet is a reference example. It can be seen that it is preferable that there is an overlapping portion of the hydrophobic region in which only the hydrophobic region overlaps vertically as in 1.

1,1A Laminated sheet 1S1,1S2 Laminated sheet surface 2 Base sheet 2F Hydrophobic fiber 3 Cellulose fiber layer 3F Cellulose fiber 4 Hydrophobic region 5 Hydrophilic region 10 Disposable diaper (absorbent article)
11 Front sheet 12 Back sheet 13 Absorbent 14 Absorbent core 15 Core wrap sheet (laminated sheet)
20 Sheet side edge overlapping part 30 Wet paper machine 31 Paper machine 32 Slurry supply device 33 Suction box 34, 36 Belt conveyor 35 Press roll 37 Yankee dryer 38 Roll roll 40 Molded sheet

Claims (8)

A laminated sheet in which a cellulosic fiber layer containing cellulosic fibers is partially laminated on a base sheet containing hydrophobic fibers.
The laminated sheet has a hydrophobic region formed of an exposed portion of the base material sheet and a hydrophilic region formed of an exposed portion of the cellulosic fiber layer on at least one surface, and the hydrophilic region extends in one direction. The hydrophilic region and the hydrophobic region are adjacent to each other in a direction orthogonal to the extending direction.
A laminated sheet in which the base material sheet and the cellulosic fiber layer are in close contact with each other due to entanglement of fibers. A laminated sheet in which a cellulosic fiber layer containing cellulosic fibers is partially laminated on a base sheet containing hydrophobic fibers.
The laminated sheet has a hydrophobic region formed of an exposed portion of the base material sheet and a hydrophilic region formed of an exposed portion of the cellulosic fiber layer on at least one surface, and the hydrophilic region extends in one direction. The hydrophilic region and the hydrophobic region are adjacent to each other in a direction orthogonal to the extending direction.
A laminated sheet in which the basis weight of the cellulosic fiber layer is ^{more than 0 g / m 2 and} 10 g / m ^{2 or less.} The laminated sheet according to claim 1 or 2, wherein the hydrophobic regions are present on both sides of the hydrophilic region in a direction orthogonal to the extending direction thereof. The laminated sheet according to any one of claims 1 to 3, wherein the plurality of hydrophilic regions and the plurality of hydrophobic regions are alternately present in a direction orthogonal to the extending direction of the plurality of hydrophilic regions. The laminated sheet according to any one of claims 1 to 4, wherein the hydrophobic region exists at both ends of the laminated sheet in a direction orthogonal to the extending direction of the hydrophilic region on the surface having the hydrophilic region. .. An absorbent article having the laminated sheet according to any one of claims 1 to 5. It has a vertical direction corresponding to the front-back direction of the wearer and a horizontal direction orthogonal to the vertical direction, and has a liquid-retaining absorbent core and a skin-facing surface and a non-skin-facing surface of the absorbent core wrapped around the absorbent core. A core wrap sheet that covers the surface is provided, and on the non-skin facing surface side of the absorbent core, both side edges of the core wrap sheet along the vertical direction overlap to form a sheet side edge overlapping portion. Orthogonal
The core wrap sheet is the laminated sheet, and the extending direction of the hydrophilic region in the laminated sheet coincides with the vertical direction.
The absorbency according to claim 6, wherein the sheet side edge overlapping portion has a hydrophobic region overlapping portion in which the hydrophobic region on one of the side edge portions of the core wrap sheet and the hydrophobic region on the other overlap. Goods. A papermaking process in which a slurry containing cellulosic fibers is supplied to a base sheet and a cellulosic fiber layer is partially formed on one side of the base sheet by papermaking.
A method for producing a laminated sheet, which comprises a dividing step of cutting the laminated sheet obtained through the papermaking step at a non-forming position of the cellulosic fiber layer and dividing the laminated sheet into a plurality of layers.

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