JP6864589B2 - Laminated sheet and its manufacturing method - Google Patents

Description

The present invention relates to a laminated sheet and a method for producing the same.

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, in Patent Document 1, a surface material of a sanitary material such as a disposable diaper is characterized in that 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. Is described. 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 continuous or discontinuous on the non-woven fabric surface by wet papermaking. It is a composite paper composed of a papermaking layer formed in a laminated manner, and is characterized in that 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. Composite paper is listed.

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

Absorbent articles such as disposable diapers and sanitary napkins generally include an absorber that absorbs excrement. The absorber has an absorbent core made of a laminated fiber such as hydrophilic fibers and a core wrap sheet that covers the absorbent core. As the core wrap sheet, paper such as tissue paper obtained by a wet papermaking method is widely used. Since such core wrap sheets have relatively narrow gaps between fibers, there is room for improvement in the permeability of highly viscous liquids such as loose stools and menstrual blood.
Further, the sheets described in Patent Documents 1 and 2 are also insufficient in terms of permeability of highly viscous liquids such as loose stools and menstrual blood.

Therefore, an object of the present invention is to provide a laminated sheet and a method for producing the same, which can eliminate the drawbacks of the above-mentioned prior art, and an absorbent article using the laminated sheet.

The present invention is a laminated sheet having a long fiber non-woven fabric layer containing hydrophobic long fibers and a cellulose-based fiber layer mainly composed of cellulose-based fibers provided on one side or both sides of the long fiber non-woven fabric layer. The long fiber non-woven fabric layer has a plurality of concave portions and convex portions on the surface in contact with the cellulose-based fiber layer, and the cellulose-based fiber layer is laminated on the concave portions, and the long-fiber non-woven fabric layer is laminated. Provided is a laminated sheet in which the interface between the layer and the cellulose fiber layer is in close contact with each other and the ventilation resistance of the laminated sheet is 0.001 kPa · s / m or more and 0.08 kPa · s / m or less. It is a thing.

Further, in the present invention, the slurry containing the cellulosic fibers is supplied onto a base sheet made of a long fiber non-woven fabric containing hydrophobic long fibers, and the cellulosic fiber layer is formed on the base sheet by papermaking. The present invention provides a method for producing a laminated sheet, which comprises a papermaking process for forming and has a neck-in ratio of 20% or less obtained by the following formula (1).
Neck-in rate (%) = (W _0- W ₁ ) / W ₀ x 100 ... (1)
W ₀ : Length of the base sheet in a direction orthogonal to the transport direction of the base sheet W ₁ : Length of the laminated sheet in the direction orthogonal to the transport direction

The present invention also provides an absorbent article in which the laminated sheet is used as a core wrap sheet for coating an absorbent core.

The laminated sheet of the present invention is excellent in the effect of suppressing liquid diffusion such as loose stool and menstrual blood.
According to the method for producing a laminated sheet of the present invention, it is possible to efficiently produce a laminated sheet having an excellent effect of suppressing liquid diffusion such as loose stool and menstrual blood.
The absorbent article of the present invention is excellent in the effect of suppressing liquid diffusion such as loose stool and menstrual blood.

FIG. 1 is a cross-sectional view taken along the thickness direction showing an embodiment of the laminated sheet of the present invention. FIG. 2A is an enlarged cross-sectional view showing a main part of the laminated sheet shown in FIG. 1, and FIG. 2B is an enlarged cross-sectional view showing a sheet not having the configuration of the present invention. FIG. 3 is an enlarged cross-sectional view schematically showing the long fiber non-woven fabric layer according to the present invention. FIG. 4 is a cross-sectional view of an absorbent article using the laminated sheet according to the present invention as a core wrap sheet. FIG. 5 is a schematic view showing an apparatus suitably used for manufacturing the laminated sheet of the embodiment shown in FIG.

Hereinafter, the present invention will be described based on the preferred embodiment with reference to the drawings. FIG. 1 shows a cross-sectional view taken along the thickness direction of one embodiment of the laminated sheet 1 of the present invention.
As shown in FIG. 1, the laminated sheet 1 is mainly composed of a long-fiber non-woven fabric layer 20 containing hydrophobic long fibers 21 and a cellulosic fiber 26 provided on one side or both sides of the long-fiber non-woven fabric layer 20. It has a laminated structure with the resulting cellulosic fiber layer 25.
In FIG. 1, for convenience of explanation of the present invention, the long fibers 21 and the cellulosic fibers 26 are shown by lines having different thicknesses, but they are irrelevant to the actual thicknesses of both fibers 21 and 26.

The long-fiber non-woven fabric layer 20 contains a long-fiber non-woven fabric containing hydrophobic long fibers 21 as a constituent material thereof. Examples of the long-fiber non-woven fabric include spunbonded non-woven fabrics and laminated non-woven fabrics having a spunbond layer and a melt-blown layer. Examples of the laminated non-woven fabric having a spunbond layer and a melt-blown layer include spunbond-melt-blown (SM) non-woven fabrics. Examples thereof include 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), spunbond-spunbond-melt blown-spunbond (SSMS) non-woven fabric and the like.
The long-fiber non-woven fabric preferably has fused portions in which the constituent fibers are fused by heat-sealing, ultrasonic sealing, embossing, or the like in a dispersed state in a plan view, and preferably has scattered points. ..
The long-fiber non-woven fabric constituting the long-fiber non-woven fabric layer 20 is preferably 50% or more, more preferably, from the viewpoint of imparting sufficient hydrophobicity to the mass of the long-fiber non-woven fabric in a blending ratio of hydrophobic long fibers. Is 70% or more, and is preferably 98% because it contains additives such as oils for imparting properties such as slipperiness and hydrophobicity required in the production stage of the non-woven fabric, and binders for maintaining strength. Hereinafter, it is more preferably 90% or less, preferably 50% or more and 98% or less, and more preferably 70% or more and 90% or less.

Examples of the constituent resin of the hydrophobic long fiber 21 include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, and polyamides such as nylon, and these may be used alone or in combination of two or more. ..
Whether or not the fiber is 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 hydrophobic. Sex. 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 contact angle of the long fibers 21 with water is 90 degrees or more. With such a configuration, when the highly viscous liquid comes into contact with the long-fiber non-woven fabric layer 20 of the laminated sheet 1, the hydrophobicity of the long-fiber non-woven fabric layer 20 prevents the high-viscosity liquid from diffusing on the surface of the long-fiber non-woven fabric layer 20. can do. The long fibers may be treated with a hydrophilic agent such as an oil agent or a water repellent agent as long as the effects of the present invention are not impaired.

<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.

The diameter of the long fiber 21 is preferably 0.5 μm or more, more preferably 5 μm or more, preferably 50 μm or less, more preferably 30 μm or less, and preferably 0.5 μm or more and 50 μm or less, more preferably 5 μm. It is 30 μm or more and 30 μm or less.

The bulk density of the long fibers 21 is preferably 0.01 g / cm ³ or more, more preferably 0.03 g / cm ³ or more, and preferably 0.2 g / cm ³ or less, more preferably 0.1 g / cm. ^{It is 3} or less, preferably 0.01 g / cm ³ or more and 0.2 g / cm ³ or less, and more preferably 0.03 g / cm ³ or more and 0.1 g / cm ³ or less.
The bulk density is measured by using a laser displacement meter, placing a metal plate with a diameter of 5.6 cm on long fibers, measuring the thickness (μm) under pressure of 50 Pa, and measuring the basis weight (g / m ² ). The bulk density (g / cm ³ ) is calculated by dividing by the thickness (μm).

The long fiber non-woven fabric layer 20 has irregularities on the surface in contact with the cellulosic fiber layer 25. As shown in FIG. 2, the unevenness of the long fiber non-woven fabric layer 20 of the present embodiment is composed of a plurality of concave portions 23 and convex portions 22, and the basis weight of the long fibers 21 in the concave portions 23 is lower than that of the convex portions 22. By doing so, the concave portion 23 and the convex portion 22 are formed. The unevenness of the long-fiber non-woven fabric layer is mainly formed by the difference in basis weight (texture, etc.) when produced by a spinning method such as spunbond or melt blown. Further, the difference between the average height of the surface in contact with the cellulosic fiber layer 25 and the height of the long-fiber non-woven fabric layer 20 at each concave portion or each convex portion does not exceed twice the average thickness of the long-fiber non-woven fabric layer. And. The average height of the surface in contact with the cellulosic fiber layer 25, the height of the long-fiber non-woven fabric layer 20 in the concave portion 23, and the height of the long-fiber non-woven fabric layer 20 in the convex portion 22 will be described later. Other methods for forming irregularities on the long-fiber non-woven fabric layer 20 include embossing by heat and pressure, ultrasonic waves, and the like.

A cellulosic fiber layer 25 composed mainly of cellulosic fibers 26 is provided on one side or both sides of the long fiber non-woven fabric layer 20. Examples of the cellulosic fiber 26 include wood pulp, natural cellulose fiber such as cotton, and regenerated cellulose fiber such as rayon.
The content of the cellulosic fiber 26 in the cellulosic fiber layer 25 is preferably 50% or more, more preferably 70% or more from the viewpoint of imparting hydrophilicity, and the binder component for binding the cellulosic fiber and the wetness. From the viewpoint of containing a chemical such as paper strength, it is preferably 98% or less, more preferably 92% or less, and preferably 50% or more and 98% or less, more preferably 70% or more and 92% or less.
Further, the contact angle of the cellulosic fiber 26 with water is less than 30 degrees.

The long-fiber non-woven fabric layer 20 and the cellulosic fiber layer 25 are in close contact with each other. Specifically, as shown in FIG. 2, the cellulosic fiber layer 25 is such that the cellulosic fibers 26 constituting the layer fill the inside of the recess 23 of the long fiber non-woven fabric layer 20 so that the long fiber non-woven fabric layer 20 is filled. At the interface between the two layers 20 and 25, the long fibers and the cellulose fibers of each layer are in a state of being sufficiently adhered by contact and entanglement without the intervention of the adhesive. On the other hand, when trying to improve the adhesion between the long fiber non-woven fabric layer 20 and the cellulosic fiber layer 25 by applying an adhesive, both of them are caused by the adhesive intervening between the long fiber 21 and the cellulosic fiber 26. As the distance between the fibers is increased, the ventilation resistance is increased and the hydrophilicity is decreased, so that the permeability of the highly viscous liquid is remarkably deteriorated. Here, it is judged by the following confirmation test whether or not the adhesion is sufficient.

<Confirmation test of close contact state>
First, it is confirmed by microscopic observation that there is no adhesive at the interface between the two layers of the sample sheet.
Cut the sample sheet into 5 cm squares and fold it in half. A folded sheet is sandwiched between 10 cm square plates, a weight is placed on it, pressure is applied to 3 kPa, and the mixture is allowed to stand for 10 seconds to open the fold. This operation is repeated a total of three times so that the folding direction is the same and the creases are at the same position. Prepare another 5 cm square sheet with this crease, immerse these sheets in liquid nitrogen for 10 seconds, and then use a sharp razor to make a cut in each sheet in the direction orthogonal to the crease. Put in one place.
Next, the cut section of the cut is observed using an SEM or an optical microscope to confirm the presence or absence of a gap between the long-fiber non-woven fabric layer 20 and the cellulosic fiber layer 25, that is, the state of close contact. If there is a gap, measure the gap distance in the thickness direction of the gap. Then, if the average of the gap distances in all the cut sections is smaller than 1/2 of the average thickness of the laminated sheet 1, both layers of the present invention are considered to be "in close contact" and more than 1/2 of the average thickness. If it is large, it is said that it is not in close contact. That is, if both layers of the present invention are in close contact with each other, the close contact state can be maintained even in a harsh test such as the bending test, but if the two layers are not in close contact with each other, the gap distance is increased by the bending test. .. Further, if the average gap distance is larger than 1/2 of the average thickness of the laminated sheet 1 which is much larger than the interfiber distance of each layer, it can be easily determined that a gap is formed. For example, if the fibers are strongly entangled and bound in each layer, but there is little contact or entanglement between the long fibers and the cellulosic fibers between the two layers, the two layers must be in close contact with each other. I can say. In such a laminated sheet, there are many gaps locally, and it is considered that the gaps are easily formed by the force applied to the laminated sheets (such as when the diaper is attached).

When the area of the sheet to be measured is less than 10 cm square, the above-mentioned bending is performed so that the same 3 kPa pressurization condition is obtained, and the number of cuts for observing the cut section is also the same, and the state of close contact is obtained. Perform a confirmation test.

The laminated sheet 1 in which the long-fiber non-woven fabric layer 20 and the cellulosic fiber layer 25 are laminated without gaps is obtained by a wet papermaking method using a slurry containing the cellulosic fibers 26 with the long-fiber non-woven fabric layer 20 as a base sheet, which will be described later. Can be manufactured.
From the viewpoint of filling the inside of the recess 23 of the long-fiber non-woven fabric layer 20 with the cellulosic fiber 26, the cellulosic fiber 26 preferably has the following physical properties.
The average fiber length of the cellulosic fiber 26 is preferably 0.5 mm or more, more preferably 2 mm or more, preferably 10 mm or less, more preferably 5 mm or less, and preferably 0.5 mm or more and 10 mm or less. It is preferably 2 mm or more and 5 mm or less.
The fiber width of the cellulosic fiber 26, that is, the diameter of the cellulosic fiber 26 is preferably 1 μm or more, more preferably 10 μm or more, preferably 80 μm or less, more preferably 50 μm or less, and preferably 1 μm or more and 80 μm. Hereinafter, it is more preferably 10 μm or more and 50 μm or less.
The fiber roughness of the cellulosic fiber 26 is preferably 50 μg / m or more, more preferably 150 μg / m or more. The larger the fiber roughness, the lower the bulk density of the cellulosic fiber layer and the larger the voids between the fibers. Therefore, the liquid permeability of the laminated sheet is improved, and the liquid diffusibility described later is further suppressed. Further, from the viewpoint of ensuring the sheet strength, 500 μg / m or less is preferable. Further, it is preferably 50 μg / m or more and 500 μg / m or less, and more preferably 150 μg / m or more and 500 μg / m or less.

<Measurement of average fiber length, fiber width and fiber roughness>
Cellulose fibers are identified and isolated from the sheet to be measured, and 1.5 g or more of fiber samples are collected. A method for distinguishing and isolating long fibers and cellulosic fibers will be described later.
The measurement is performed using a fiber roughness meter FS-200 (manufactured by KAJAANI ELECTRONICS LTD.). First, in order to determine the true mass of the fiber to be measured, the fiber is dried in a vacuum dryer at 100 ° C. for 1 hour to remove water present in the fiber. Accurately weigh 1 g from the fibers thus dried (error ± 0.1 mg). Next, the weighed fibers are completely dissolved in 150 ml of water with the mixer attached to the fiber roughness meter, taking care not to damage the fibers as much as possible, until the total amount reaches 5000 ml. Dilute with water to obtain a diluent. Accurately weigh 50 ml from the obtained diluted solution and use this as a fiber roughness measurement solution, and calculate the target average fiber length and fiber roughness according to the operation procedure of the fiber roughness meter. In addition, in the calculation of the average fiber length, the value calculated by the following formula (2) based on the above operation procedure is used.

The bulk density of the cellulose-based fiber 26 is preferably 0.01 g / cm ³ or more, more preferably 0.03 g / cm ³ or more, and ensures liquid permeability from the viewpoint of ensuring the strength of the cellulose-based fiber layer. From this point of view, it is preferably 0.5 g / cm ³ or less, more preferably 0.3 g / cm ³ or less, and preferably 0.01 g / cm ³ or more and 0.5 g / cm ³ or less, more preferably 0. 03g / cm ³ or more 0.3g / cm ³ or less.

The lower the ventilation resistance of the laminated sheet 1 is, the better it is from the viewpoint of liquid permeability. However, in the configuration of the laminated sheet of the present invention, the lower limit is not 0, but 0.001. The upper limit is preferably 0.08 kPa · s / m or less, and more preferably 0.05 kPa · s / m or less. The ventilation resistance is an index indicating the size of the voids between the fibers. The smaller the ventilation resistance, the larger the voids between the fibers, and the larger the ventilation resistance, the smaller the voids between the fibers. The ventilation resistance referred to here is measured using a breathability tester "KES-F8-AP1 AIR PERMEABILITY TESTER" (trade name) manufactured by Kato Tech Co., Ltd. Specifically, the ventilation resistance of the sheet (laminated sheet) to be evaluated is measured at an arbitrary 12 points using a breathability tester according to a conventional method, and the average value thereof is taken as the ventilation resistance of the sheet.

The laminated sheet 1 of the present invention has a ventilation resistance within the above-mentioned range, and also has a hydrophobic long-fiber non-woven fabric layer 20 and a hydrophilic cellulose-based fiber layer 25, whereby the laminated sheet 1 Has a hydrophilic gradient in the thickness direction of. Further, the long-fiber non-woven fabric layer 20 and the cellulosic fiber layer 25 are laminated without gaps, that is, in close contact with each other. With such a configuration, the laminated sheet 1 is excellent in permeability of a highly viscous liquid such as loose stool and menstrual blood, and also has an effect of suppressing the diffusion of the highly viscous liquid in the plane direction of the laminated sheet 1 (hereinafter, liquid). It is also excellent in suppressing diffusion). Specifically, when the ventilation resistance of the laminated sheet 1 is within the above range, the voids between the fibers can be appropriately increased, so that a highly viscous liquid can be easily permeated and is excellent. The effect of suppressing liquid diffusion is achieved. Further, by having a hydrophilic gradient in the thickness direction of the laminated sheet 1, the highly viscous liquid is excellently attracted from the long-fiber non-woven fabric layer 20 to the cellulosic fiber layer 25. Further, by laminating the long fiber non-woven fabric layer 20 and the cellulosic fiber layer 25 in close contact with each other, the highly viscous liquid can be easily transmitted from the long fibers 21 to the cellulosic fibers 26, so that the highly viscous liquid can be used. Excellent in pullability. On the other hand, if there is a gap between the long fiber non-woven fabric layer 20 and the cellulosic fiber layer 25 [see FIG. 2B], the conduction path of the highly viscous liquid is interrupted by the gap, making it difficult to draw in the highly viscous liquid. ..

A method for measuring the basis weight of long-fiber non-woven fabric and cellulose fiber is shown. Examples of the method for identifying the cellulose fibers in the laminated sheet include a method of observing the shape using an SEM image, a staining method (JIS P 8120), a method of hydrolyzing the cellulose and then analyzing the constituent sugars by an HPLC method or the like. Method can be used. Further, since the long-fiber non-woven fabric is a continuous fiber that is not interrupted in the length direction, it can be identified by a low-magnification image, and the type of resin constituting the fiber can be specified by a DSC (differential thermal analyzer). The basis weight of the long-fiber non-woven fabric layer and the cellulosic fiber layer in the laminated sheet is determined by measuring the weight per unit area of each isolated layer when each layer can be isolated by delamination with an adhesive tape or the like. If isolation is not possible, measure the average thickness of each layer 20 and 25 from the photograph of the cross-sectional area of the laminated sheet, and calculate the ratio of the average thickness of each layer 20 and 25 to the average thickness of the laminated sheet 1 per tsubo of the entire laminated sheet. Multiply by the amount to obtain the basis weight of each layer.

The basis weight of the long fiber non-woven layer 20 is preferably 5 g / m ² or more, more preferably 8 g / m ² or more, and ensures the permeability of a highly viscous liquid or the like, in order to ensure the strength of the laminated sheet 1. Therefore, it is preferably 15 g / m ² or less, more preferably 12 g / m ² or less, and preferably 5 g / m ² or more and 15 g / m ² or less, more preferably 8 g / m ² or more and 12 g / m ² or less. .. It is preferable that the long-fiber non-woven fabric 21a constituting the long-fiber non-woven fabric layer 20 has a basis weight within the above range.

Further, from the viewpoint of making the cellulose-based fiber layer 25 hydrophilic and further improving the permeability of the highly viscous liquid, the basis weight of the cellulosic fiber layer 25 is preferably 0.5 g / m ² or more, more preferably 1 g / m ² or more. Further, in order to increase the voids between the fibers and ensure the permeability of the highly viscous liquid, it is preferably 10 g / m ² or less, more preferably 6 g / m ² or less, and preferably 0.5 g / m ² or more and 10 g. / M ² or less, more preferably 1 g / m ² or more and 6 g / m ² or less.

As shown in FIG. 1, the laminated sheet 1 of the present embodiment has a penetrating cellulosic fiber 27 in which some cellulosic fibers penetrate from one side of the long-fiber non-woven fabric layer 20 in the thickness direction to the other side. Have. With such a configuration, the drawability of the highly viscous liquid can be further improved. As described above, in the laminated sheet 1, it is preferable that a part of the cellulosic fibers 26 penetrates the long-fiber non-woven fabric layer 20 and is exposed on one side of the long-fiber non-woven fabric layer 20. The fact that it is exposed on one side is confirmed by the [method for confirming penetrating cellulosic fibers] described later in the examples of the present invention.
^{The number of penetrating cellulosic fibers 27 per unit area (10 cm 2} ) in the long-fiber non-woven fabric layer 20 is preferably 3 or more and 300 or less, and more preferably 10 or more and 100 or less.

The long-fiber non-woven fabric layer 20 has irregularities on the surface in contact with the cellulosic fiber layer 25, and the concave portions and convex portions constituting the irregularities are formed by, for example, embossing the long-fiber non-woven fabric 21a which is the base sheet 20a. Can be formed. In this case, from the viewpoint of improving the capillary force in the recess 23 in which the long fibers 21 are densified by embossing and preventing the formation of a gap between the long fiber non-woven fabric layer 20 and the cellulosic fiber layer 25. The area ratio of the recesses 23 constituting the unevenness is preferably 3% or more, more preferably 5% or more, further preferably 11% or more, and preferably 35% or less, more preferably 28% or less, still more preferable. Is 18% or less, preferably 3% or more and 35% or less, more preferably 5% or more and 28% or less, and further preferably 11% or more and 18% or less.
The area ratio of the recess is obtained by image analysis of a real photograph. At this time, if there is a fiber defect in the recess, manual correction is performed and measurement is performed assuming that there is a fiber.

From the same viewpoint, the thickness t2 of the long-fiber non-woven fabric layer 20 in the recesses 23 forming the unevenness formed by the embossing is preferably 10% or more, more than the average thickness t1 of the long-fiber non-woven fabric layer 20. It is preferably 30% or more, preferably 90% or less, more preferably 60% or less, and preferably 10% or more and 90% or less, more preferably 30% or more and 60% or less. The average thickness t1 of the long-fiber non-woven fabric layer 20 and the thickness t2 of the recess are defined as follows. The distance (difference) t1 between the average height positions h1 and h2 on the surfaces 21c and 21d of the long-fiber non-woven fabric layer 20 is referred to as the average thickness of the long-fiber non-woven fabric layer 20 (see FIG. 3). Further, the recess 23 refers to a region in a state of being recessed toward the other surface side from the average height on one surface of the long fiber non-woven fabric layer 20, and as shown in FIG. 3, the height of the most recessed portion 23a in the recess 23. The distance (difference) t2 between the position h3 and the average height (average height h1 of the surface 21c in FIG. 3) on the other surface, which is the surface opposite to the surface on which the recess 23 is formed, is defined as the recess. It is called the thickness of the long fiber non-woven fabric layer 20 in No. 23. The convex portion 22 refers to a region in a state of protruding beyond the average height on one surface of the long fiber non-woven fabric layer 20, and the height position h4 of the most protruding portion 22a of the convex portion 22 and the convex portion 22. The distance (difference) t3 from the average height (average height h1 of the surface 21c in FIG. 3) on the surface opposite to the surface on which the portion 22 is formed is referred to as the thickness of the long-fiber non-woven fabric layer 20 on the convex portion 22. .. The surface shape of these long fiber non-woven fabric layers 20 is measured by an image analysis of a cross-sectional photograph such as an SEM image or a method conforming to JIS B 0601 such as a surface roughness measuring machine.

As described above, the laminated sheet 1 of the present invention has excellent permeability of a highly viscous liquid, and is suitable for various applications in which such features are utilized. In particular, the laminated sheet 1 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. The laminated sheet 1 of the present invention is particularly effective for highly viscous liquids such as loose stools and menstrual blood, and is therefore particularly useful as a core wrap sheet in disposable diapers.

As an example of the absorbent article using the laminated sheet 1, it is an absorbent article composed of an absorbent core 14a and a core wrap sheet 14b covering the absorbent core 14a, and the core wrap sheet 14b is the laminated sheet 1. Things can be mentioned. More specifically, the absorbent article (diaper 100) using the laminated sheet 1 has a ventral portion located on the ventral side of the wearer, a dorsal portion located on the dorsal side, and a dorsal portion in the longitudinal direction thereof. It has a crotch that is located between the ventral and dorsal sides. Further, as shown in FIG. 4, the diaper 100 includes a liquid-permeable surface sheet 12 that forms a skin-facing surface, a liquid-impermeable or water-repellent back sheet 13 that forms a non-skin-facing surface, and both of these sheets. It includes a liquid-retaining absorber 14 arranged between 12 and 13. The diaper 100 has a seat 15 for forming a three-dimensional gather having an elastic member 15a, and due to the contraction of the elastic member 15a, a three-dimensional gather that stands up toward the skin side of the wearer is formed at the inseam in the wearing state. It is formed. Further, the leg elastic member 16 is arranged in the extended state in the portion arranged around the leg of the inseam, and the contraction of the leg portion elastic member 16 improves the fit to the wearer's leg around the inseam in the wearing state. Leg gathers are formed.

As shown in FIG. 4, the absorber 14 includes an absorbent core 14a and a core wrap sheet 14b (laminated sheet 1). The laminated sheet 1 used as the core wrap sheet 14b preferably covers at least the skin-facing surface of the absorbent core 14a. In that case, the laminated sheet 1 is arranged between the surface sheet 12 and the absorbent core 14a so that the surface sheet 12 and the long-fiber non-woven fabric layer 20 of the laminated sheet 1 face each other. Among them, the long-fiber non-woven fabric layer 20 comes into contact with excrement such as stool first than the cellulosic fiber layer 25. The skin-facing surface is a surface of the absorbent article or its constituent members (for example, an absorbent core) that is directed toward the wearer's skin when the absorbent article is worn, and the non-skin-facing surface is the absorbent article or the absorbent core. It is a surface of the constituent member that is directed to the side opposite to the skin side (clothing side) when the absorbent article is worn. As the front surface sheet 12, the back surface sheet 13, and the absorbent core 14a, those usually used in this type of absorbent article can be used without particular limitation. The absorbent article using the laminated sheet 1 can be applied to a deployable or pants-type disposable diaper, a sanitary napkin, an incontinence pad, or the like.

Next, an embodiment of the method for producing the laminated sheet 1 of the present invention will be described with reference to FIG. FIG. 5 shows a wet paper machine 3 capable of preferably producing the laminated sheet 1 of the present invention. The wet paper machine 3 includes a paper machine 31, a slurry charging device 32, a press roll 34, and a Yankee dryer 35.
The production method of the present embodiment includes a papermaking step of adding a slurry containing cellulosic fibers to a base sheet 20a made of a long fiber non-woven fabric 21a mainly composed of long fibers to make a cellulosic fiber layer. Further, the manufacturing method of the present embodiment includes a dehydration step of dehydrating the molded sheet obtained in the manufacturing step, a drying step of drying the molded sheet after dehydration, and a winding step of winding the molded sheet after drying. including.

The papermaking process will be described. In the papermaking step, as shown in FIG. 5, a slurry 26a containing a cellulosic fiber 26 is supplied onto a base sheet 20a made of a long fiber non-woven fabric 21a containing hydrophobic long fibers 21, and the slurry is based by a wet papermaking method. This is a step of forming the cellulosic fiber layer 25 on the material sheet 20a. Specifically, the long-fiber non-woven fabric 21a supplied from the long-fiber non-woven fabric roll 21b is used as a base sheet 20a, the base sheet 20a is placed on the papermaking net 31, and the base sheet 20a on the papermaking net 31 is placed. The slurry 26a containing the cellulosic fiber 26 is poured from the slurry charging device 32. The water in the poured slurry 26a sequentially permeates the base sheet 20a and the papermaking net 31 and flows down from below the papermaking net 31, and the cellulosic fibers 26 in the slurry 26a are the constituent fibers of the base material sheet 20a. It is entangled with (long fibers 21) and stays in the base sheet 20a, whereby a molded sheet 10 containing the long fibers 21 and the cellulosic fibers 26 is formed on the papermaking net 31. The molded sheet 10 is delivered from the papermaking net 31 to the belt conveyor 37a.

The slurry containing the cellulose-based fiber can contain a fiber component other than the cellulose-based fiber, and the fiber component includes, for example, a polyolefin resin such as polyethylene (PE) and polypropylene (PP), polyethylene terephthalate (PET), and the like. Examples thereof include fibers containing a polyester resin such as polybutylene terephthalate (PBT) alone or containing two or more components, acrylic fibers, nylon fibers, urethane fibers, animal hair fibers and the like. In addition, the slurry may also contain a wet paper strength agent, a dry paper strength agent, a texture improver, a yield improver, a flocculant, a pH adjuster, an antibacterial agent, a deodorant, and a flame retardant.

In the production method of the present embodiment, when the slurry 26a is made in the papermaking process, the water in the slurry is sucked and dehydrated by the suction box 33. The stronger the suction dehydration and the faster the suction speed, the easier it is to fill the inside of the recess 23 of the long-fiber non-woven fabric layer 20 with the cellulosic fiber 26. When the basis weight of this recess is low, the suction rate is relatively higher than that of other portions having a high basis weight, and more cellulosic fibers fill the recess. As described above, the papermaking step preferably includes a step of sucking and dehydrating the water content in the slurry 26a added to the base sheet 20a.
Further, it is preferable to increase the suction force in suction dehydration in that a part of the cellulosic fibers 26 in the slurry 26a can be penetrated through the base sheet 20a (long-fiber non-woven fabric 21a).

Next, a dehydration step of dehydrating the molded sheet 10 obtained in the papermaking step will be described. In the dehydration step, from the viewpoint of maintaining the shape of the molded sheet 10 (shape retention) and maintaining the mechanical strength, dehydration may be performed until the water content (weight water content, the same applies hereinafter) becomes 70% or less. It is preferable to dehydrate to 60% or less. In the dehydration step in the present embodiment, dehydration is carried out by passing the molded sheet 10 conveyed by the belt conveyor 37a between the pair of press rolls 34 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.

Next, the drying process will be described. In the present embodiment, the molding sheet 10 conveyed by the belt conveyor 37b comes into contact with the surface of the Yankee dryer 35 to dry the molding sheet 10. The drying method in the drying step can be appropriately selected depending on the thickness and water content of the molded sheet 10 after dehydration, the water content after drying, and the like. Examples of the drying method include contact with a heating structure (heating element), spraying of heated air or steam (superheated steam), vacuum drying, electromagnetic wave heating, energization heating, and the like. Although dehydration and drying are performed separately, drying can be performed at the same time in combination with the above-mentioned dehydration method. By drying the molded sheet 10 in this way, the laminated sheet 1 can be obtained.

If necessary, the production method of the present invention may include a winding step of winding the laminated sheet 1 obtained after drying into a roll shape. Further, before winding the laminated sheet 1 into a roll shape, the laminated sheet 1 can be subjected to processing such as crepe processing, slit processing, trimming processing, and changing the form, if necessary. Further, by laminating the laminated sheet 1 alone or in layers, or by superimposing it on another sheet such as paper, cloth (woven fabric or non-woven fabric), film, etc., and pressurizing it, or by further pressurizing it to perform embossing or needle punching. , A plurality of sheets can be laminated and integrated, and uneven molding and drilling can be performed.

Further, in the present embodiment, the transport path of the long fiber non-woven fabric 21a, the slurry 26a and the laminated sheet 1 is composed of the belt conveyors 37a and 37b and the winding roll 36. The transport path may be configured mainly by combining a winding roll, a belt conveyor, a vacuum conveyor, a roller conveyor, and the like, and a transport means conventionally used for transporting sheet members can be appropriately selected and used.

From the viewpoint of preventing the size of the fiber gaps in the laminated sheet 1 from shrinking and the permeability of the highly viscous liquid from decreasing, the neck-in rate required by the following formula (1) in the production method of the present invention is 20% or less. It is preferably 15% or less, and more preferably 10% or less. The neck-in ratio is the ratio (%) of the length of the laminated sheet 1 in the CD direction to the length of the base sheet 20a (long fiber non-woven fabric 21a) in the CD direction, and is calculated by the following formula (1). The long-fiber non-woven fabric 21a is a long-fiber non-woven fabric 21a as a raw material used in the papermaking process. The CD direction is a direction orthogonal to the transport direction (MD direction) of the base sheet 20a. The neck-in rate can be adjusted by, for example, the tension applied to the base sheet 20a. The tension can be lowered by adjusting the speed of each part related to the speed of the transport path such as the drive roll 38 for rotating the belt conveyor and the winding roll 36. By lowering this tension, the neck-in rate can be lowered.
Neck-in rate (%) = (W _0- W ₁ ) / W ₀ x 100 ... (1)
W ₀ : Length of the base sheet 20a (long fiber non-woven fabric 21a) in the _{CD direction W 1} : Length of the laminated sheet 1 in the CD direction

Although the preferred embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

Regarding the above-described embodiment, the following laminated sheet, a method for producing the laminated sheet, and an absorbent article are further disclosed.
<1>
A laminated sheet having a long-fiber non-woven fabric layer containing hydrophobic long fibers and a cellulosic fiber layer mainly composed of cellulosic fibers provided on one side or both sides of the long-fiber non-woven fabric layer.
The long-fiber non-woven fabric layer has a plurality of concave portions and convex portions on a surface in contact with the cellulose-based fiber layer, and the cellulose-based fiber layer is laminated on the concave portions.
The interface between the long fiber non-woven fabric layer and the cellulosic fiber layer is in close contact with each other.
A laminated sheet having a ventilation resistance as the laminated sheet of 0.001 kPa · s / m or more and 0.08 kPa · s / m or less, preferably 0.05 kPa · s / m or less.

<2>
The laminated sheet according to <1>, wherein the long fibers have a contact angle with water of 90 degrees or more, and the cellulosic fibers have a contact angle with water of less than 90 degrees.
<3>
In the long-fiber non-woven fabric constituting the long-fiber non-woven fabric layer, the blending ratio of the long fibers is preferably 50% or more, more preferably 70% or more, and preferably 98% with respect to the mass of the long-fiber non-woven fabric. % Or less, more preferably 90% or less, preferably 50% or more and 98% or less, more preferably 70% or more and 90% or less, the laminated sheet according to <1> or <2>.
<4>
The state in which the interface between the long fiber non-woven fabric layer and the cellulosic fiber layer is in close contact means that the long fiber and the cellulosic fiber are in contact with each other or the cellulosic fiber is in contact with each other without substantially interposing an adhesive at the interface between the two layers. The laminated sheet according to any one of <1> to <3>, which is in a state of being sufficiently adhered by entanglement.
<5>
The state in which the interface between the long-fiber non-woven fabric layer and the cellulosic fiber layer is in close contact is that the average of the gap distances in all the cut sections is 1/2 of the average thickness of the laminated sheet by the following confirmation test of the close contact state. The laminated sheet according to any one of <1> to <4>, which is in a smaller state.
(Confirmation test of close contact state)
It is confirmed by microscopic observation that no adhesive is present at the interface between the long fiber non-woven fabric layer and the sheet having the cellulosic fiber layer.
Cut the sheet into 5 cm squares and fold it in half. The folded sheet is sandwiched between 10 cm square plates, a weight is placed on the sheet, pressure is applied to 3 kPa, and the mixture is allowed to stand for 10 seconds to open the fold. This operation is repeated a total of three times so that the fold direction is the same and the creases are at the same position. Prepare another 5 cm square sheet with creases by the above operation, immerse these sheets in liquid nitrogen for 10 seconds, and then use a sharp razor to make a cut in the direction orthogonal to the crease. Put in 3 places each.
Next, the cut section of the cut in the sheet is observed using an SEM or an optical microscope to confirm the presence or absence of a gap between the long fiber non-woven fabric layer and the cellulosic fiber layer. If there is a gap, the gap distance in the thickness direction of the gap portion is measured, and the average of the gap distances in all the cut sections is obtained. If the average of the gap distances is smaller than 1/2 of the average thickness of the laminated sheets, it is considered to be "in close contact", and if it is larger than 1/2 of the average thickness, it is "not in close contact". ..
<6>
Any one of <1> to <5>, wherein a part of the cellulosic fibers penetrates the long fiber non-woven fabric layer and has penetrating cellulose exposed on one side of the long fiber non-woven fabric layer. The laminated sheet described in.
<7>
^{The number of the penetrating cellulosic fibers per unit area (10 cm 2} ) in the long-fiber non-woven fabric layer is preferably 3 or more and 300 or less, more preferably 10 or more and 100 or less, according to the above <6>. Laminated sheet.
<8>
The fiber roughness of the cellulosic fiber is preferably 50 μg / m or more, more preferably 150 μg / m or more, preferably 500 μg / m or less, and preferably 50 μg / m or more and 500 μg / m or less. The laminated sheet according to any one of <1> to <7>, preferably 150 μg / m or more and 500 μg / m or less.

<9>
The average fiber length of the cellulosic fibers is preferably 0.5 mm or more, more preferably 2 mm or more, preferably 10 mm or less, more preferably 5 mm or less, and preferably 0.5 mm or more and 10 mm or less. The laminated sheet according to any one of <1> to <8>, preferably 2 mm or more and 5 mm or less.
<10>
The diameter of the cellulosic fiber is preferably 1 μm or more, more preferably 10 μm or more, preferably 80 μm or less, more preferably 50 μm or less, and preferably 1 μm or more and 80 μm or less, more preferably 10 μm or more and 50 μm or less. The laminated sheet according to any one of <1> to <9>.
<11>
The bulk density of the cellulose-based fiber is preferably 0.01 g / cm ³ or more, more preferably 0.03 g / cm ³ or more, and preferably 0.5 g / cm ³ or less, more preferably 0.3 g / cm / cm. cm ³ or less, also preferably 0.01 g / cm ³ or more 0.5 g / cm ³ or less, more preferably less 0.03 g / cm ³ or more 0.3 g / cm ^3, the <1> to < The laminated sheet according to any one of 10>.
<12>
In the long-fiber non-woven fabric layer, the difference between the average height on the surface in contact with the cellulosic fiber layer and the height of the long-fiber non-woven fabric layer in the concave portion or the convex portion is 2 of the average thickness of the long-fiber non-woven fabric layer. The laminated sheet according to any one of <1> to <11>, which does not exceed a double.
<13>
The laminated sheet according to any one of <1> to <12>, wherein the concave portion and the convex portion of the long fiber non-woven fabric layer are formed by embossing.
<14>
The thickness of the long-fiber non-woven fabric layer in the recess is preferably 10% or more, more preferably 30% or more, and preferably 90% or less, more preferably, with respect to the average thickness of the long-fiber non-woven fabric layer. The laminated sheet according to any one of <1> to <13>, wherein is 60% or less, preferably 10% or more and 90% or less, and more preferably 30% or more and 60% or less.
<15>
The area ratio of the recess is preferably 3% or more, more preferably 5% or more, further preferably 11% or more, and preferably 35% or less, more preferably 28% or less, still more preferably 18% or less. The laminate according to any one of <1> to <14>, preferably 3% or more and 35% or less, more preferably 5% or more and 28% or less, and further preferably 11% or more and 18% or less. Sheet.
<16>
The basis weight of the long fiber non-woven layer is preferably 5 g / m ² or more, more preferably 8 g / m ² or more, preferably 15 g / m ² or less, more preferably 12 g / m ² or less, and also. The laminated sheet according to any one of <1> to <15>, preferably 5 g / m ² or more and 15 g / m ² or less, more preferably 8 g / m ² or more and 12 g / m ^{2 or less.}
<17>
The basis weight of the cellulose-based fiber layer is preferably 0.5 g / m ² or more, more preferably 1 g / m ² or more, and preferably 10 g / m ² or less, more preferably 6 g / m ² or less. The laminated sheet according to any one of <1> to <16>, preferably 0.5 g / m ² or more and 10 g / m ² or less, more preferably 1 g / m ² or more and 6 g / m ^{2 or less.} ..

<18>
The content of the cellulosic fiber in the cellulosic fiber layer is preferably 50% or more, more preferably 70% or more, preferably 98% or less, more preferably 92% or less, and preferably 50. The laminated sheet according to any one of <1> to <17>, which is% or more and 98% or less, more preferably 70% or more and 92% or less.
<19>
The diameter of the long fiber 21 is preferably 0.5 μm or more, more preferably 5 μm or more, preferably 50 μm or less, more preferably 30 μm or less, and preferably 0.5 μm or more and 50 μm or less, more preferably 5 μm. The laminated sheet according to any one of <1> to <18>, which is 30 μm or less.
<20>
The bulk density of the long fibers is preferably 0.01 g / cm ³ or more, more preferably 0.03.
g / cm ³ or more, preferably 0.2 g / cm ³ or less, more preferably 0.1 g / cm ³ or less, and preferably 0.01 g / cm ³ or more and 0.2 g / cm ³ or less, The laminated sheet according to any one of <1> to <19>, more preferably 0.03 g / cm ³ or more and 0.1 g / cm ^{3 or less.}
<21>
The method for manufacturing a laminated sheet according to any one of <1> to <20>.
A papermaking step in which a slurry containing the cellulosic fibers is supplied onto a base sheet made of the long fiber non-woven fabric containing the hydrophobic long fibers, and the cellulosic fiber layer is formed on the base sheet by papermaking. A method for manufacturing a laminated sheet.
<22>
The method for producing a laminated sheet according to <21>, wherein the neck-in rate determined by the following formula (1) is 20% or less, preferably 15% or less, and more preferably 10% or less.
Neck-in rate (%) = (W _0- W ₁ ) / W ₀ x 100 ... (1)
W ₀ : Length of the base sheet in a direction orthogonal to the transport direction of the base sheet W ₁ : Length of the laminated sheet in the direction orthogonal to the transport direction <23>
A papermaking step is provided in which a slurry containing the cellulosic fibers is supplied onto a base sheet made of a long fiber non-woven fabric containing hydrophobic long fibers, and the cellulosic fiber layer is formed on the base sheet by papermaking. And
A method for producing a laminated sheet, wherein the neck-in rate determined by the following formula (1) is 20% or less, preferably 15% or less, and more preferably 10% or less.
Neck-in rate (%) = (W _0- W ₁ ) / W ₀ x 100 ... (1)
W ₀ : Length of the base sheet in a direction orthogonal to the transport direction of the base sheet W ₁ : Length of the laminated sheet in the direction orthogonal to the transport direction <24>
The long fiber non-woven fabric has concave portions and convex portions, and has concave portions and convex portions.
The laminate according to any one of <21> to <23>, wherein the concave portion and the convex portion are formed by lowering the basis weight of the long fibers in the concave portion as compared with the convex portion. Sheet manufacturing method.
<25>
The concave portion and the convex portion of the long-fiber non-woven fabric are mainly formed by the difference in basis weight when the long-fiber non-woven fabric is produced, according to any one of <21> to <24>. Method of manufacturing laminated sheet.

<26>
The method for producing a laminated sheet according to any one of <21> to <25>, wherein the concave portion and the convex portion of the long fiber nonwoven fabric are embossed by heat or pressure or formed by ultrasonic waves.
<27>
An absorbent article having the laminated sheet according to any one of <1> to <20>.
<28>
An absorbent article in which the laminated sheet according to any one of <1> to <20> is used as a core wrap sheet for coating the absorbent core.
<29>
The absorbent article has an absorbent body including the absorbent core and the laminated sheet covering the absorbent core, and a surface sheet arranged on the skin-facing surface side of the absorbent body.
The absorption according to <28>, wherein the laminated sheet is arranged between the surface sheet and the absorbent core so that the surface sheet and the long-fiber non-woven fabric layer of the laminated sheet face each other. Sex goods.
<30>
The absorbent article according to any one of <27> to <29>, wherein the absorbent article is a disposable diaper.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to such Examples. Unless otherwise specified, "%" means "mass%".

[Example 1]
The laminated sheet 1 was manufactured using a general-purpose wet paper machine. Specifically, one type of cellulosic fiber (fiber concentration 0.1%) selected from the cellulosic fibers A to E shown in Table 1 below as shown in Table 2 below, and a wet paper strength agent (trade name "WS"). -4030 ”, manufactured by Seiko PMC Corporation) 0.5% (cellulosic fiber) 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 long-fiber non-woven fabric having a width of 300 mm shown in Table 2 below 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 long-fiber non-woven fabric to form a paper layer (fiber web). ) Was formed. ^{This paper layer was suction-dehydrated at a speed of 6 ml / (cm 2} · sec) using a suction box to obtain a molded sheet 10, and then further pressurized using a press roll to perform dehydration. After dehydration, the molded sheet was pressure-bonded to the surface of a Yankee dryer and dried to obtain a laminated sheet having a width of 260 mm. The papermaking conditions were a papermaking speed of 10 m / min. The neck-in ratio of the laminated sheet obtained by the above manufacturing method was adjusted by the winding speed of the roll 36.

In the spunbonded non-woven fabric shown in Table 2 used as the long-fiber non-woven fabric, the spunbond layer made of polypropylene resin has a fiber diameter of 18 μm as a constituent fiber. The long-fiber non-woven fabric was embossed so that the surface in contact with the cellulosic fiber layer had irregularities, and the area ratio of the recesses due to the embossing was 17.3% (oval pattern).
Table 2 also shows the basis weight (g / m ² ), bulk density (g / cm ³ ) of the long-fiber non-woven fabric, and the thickness of the long-fiber non-woven fabric layer in the recess with respect to the average thickness (t1) of the long-fiber non-woven fabric layer. The ratio (t2 / t1) of (t2) is shown.

[Examples 2 to 14]
The laminated sheet 1 was produced in the same manner as in Example 1 except that the configurations (type, basis weight, bulk density) of the cellulosic fibers and the long-fiber non-woven fabric were changed as shown in Table 2 below.
In the SMS non-woven fabric used as the long fiber non-woven fabric in Examples 13 and 14, the constituent fibers of the spunbond layer are polypropylene resin fibers having a fiber diameter of 20 μm, and the constituent fibers of the melt blown layer are polypropylene having a fiber diameter of 1.8 μm. It was a resin fiber. Further, the area ratio of the recesses formed by embossing on the surface of the SMS non-woven fabric in contact with the cellulosic fiber layer was 20.9% (oval pattern). Moreover, the suction dehydration of the paper layer was not performed in Examples 13 and 14.

[Comparative Examples 1, 2, 5-9]
Laminated sheet 1 in the same manner as in Example 1 except that the presence or absence of cellulosic fibers or long-fiber non-woven fabric, their composition (type, basis weight, bulk density), and neck-in ratio are changed as shown in Table 3 below. Manufactured.
As the spunbonded non-woven fabric and the SMS non-woven fabric used as the long-fiber non-woven fabric of each comparative example, those having the same constituent fibers as those of the above-mentioned Examples were used. Further, the spunbonded non-woven fabric and the SMS non-woven fabric in each comparative example also have irregularities on the surface in contact with the cellulosic fiber layer by embossing, and the area ratio of the recesses of the spunbonded non-woven fabric and the SMS non-woven fabric is 17.3, respectively. % And 20.9%.
In Comparative Examples 6 and 7, the paper layer was not suction-dehydrated. ^{The basis weight (g / m 2} ), bulk density (g / cm ³ ) of the long-fiber non-woven fabric used in each comparative example, and the thickness of the long-fiber non-woven fabric layer in the recess with respect to the average thickness (t1) of the long-fiber non-woven fabric layer. The ratio (t2 / t1) of (t2) is shown in Table 3.

[Comparative Example 3]
A laminated sheet was obtained by laminating a dry sheet obtained by papermaking the cellulosic fibers A shown in Table 1 below at the basis weight shown in Table 3 below and a long fiber non-woven fabric shown in Table 3 below.

[Comparative Example 4]
A dry sheet obtained by papermaking the cellulosic fibers E shown in Table 1 below at the basis weight shown in Table 3 below and a long fiber non-woven fabric shown in Table 3 below are laminated, and water flow entanglement treatment by jet water flow is performed to obtain a laminated sheet. Obtained.

Details of each cellulosic fiber in Table 1 below are as follows.
Cellulose-based fiber A: Softwood bleached kraft pulp (NBKP) (trade name "Caribbean", manufactured by Caliboo Pump and Paper).
-Cellulose fiber B: Softwood bleached kraft pulp (NBKP) (trade name "Arauco", manufactured by ARAUCO).
-Cellulose fiber C: Hardwood bleached kraft pulp (LBKP) (trade name "Riu", manufactured by Riau Andalan).
-Cellulose fiber D: Mercerized pulp (trade name "Porosenia", manufactured by ITT RAYONIER INC.).
-Cellulose fiber E: Crosslinked pulp (trade name "HBA", manufactured by Weyerhaeuser).

[Confirmation test of close contact state]
For the laminated sheets of each of the above Examples and Comparative Examples, the presence or absence of a gap between the long-fiber non-woven fabric layer and the cellulosic fiber layer was confirmed by the above-mentioned confirmation test of the adhesion state. Then, the average ratio of the gap distance to the average thickness of the laminated sheet [average of the gap distance / average thickness of the laminated sheet × 100 (%)] is shown in Tables 2 and 3 below. When the average of the gap distances in all the cut sections is smaller than 1/2 of the average thickness of the laminated sheet, that is, when the above ratio is 50% or less, both layers are considered to be "in close contact".

[Confirmation test for penetrating cellulosic fibers]
The presence or absence of penetrating cellulosic fibers in the long-fiber non-woven fabric layer was confirmed by the following method for the laminated sheets of each of the above Examples and Comparative Examples. The long-fiber non-woven fabric layer side of the laminated sheet was observed with a microscope at a magnification of 500 times, and the cellulosic fibers were dyed with a 0.1% blue dye. For this blue dye, a commercially available synthetic dye (product name: Blue No. 1, manufactured by Hodogaya Chemical Co., Ltd.) is diluted to 0.1% with deionized water, and the cellulosic fiber layer is immersed in the 0.1% dye. And dried and adjusted. At this time, the cellulose fiber layer was carefully handled so as not to move or fall off. ^{Ten 1 cm 2} sections were randomly sampled from the stained laminates. Next, an SEM image of the surface of the long-fiber non-woven fabric layer of each section was taken, and the number of cellulosic fibers penetrating the long-fiber non-woven fabric layer was determined from the SEM image and shown in Tables 2 and 3 below.

[Measurement of ventilation resistance and neck-in rate]
For the laminated sheets of each of the above Examples and Comparative Examples, the ventilation resistance and the neck-in ratio were measured by the method described above. The measurement results are shown in Tables 2 and 3.

[Preparation of absorber]
Absorbents were prepared using the laminated sheets of each of the above Examples and Comparative Examples. First, the defibrated pulp fiber aggregate (pulp sheet having a basis weight of 250 g / m ² ) was coated with the laminated sheets of the above Examples and Comparative Examples, and this was used as an absorbent core. When coated with the laminated sheet, the cellulosic fiber layer 25 was coated so as to face the pulp fiber aggregate. Next, the surface sheet of Mary's tape type S size (Kao Corporation, manufactured and sold in 2015 in Japan) of commercially available disposable diapers was peeled off by solidifying the hot melt that adheres between each material with cold spray, and superposed on the absorbent core. It was adhered using a spray glue. After bonding, the mangle was reciprocated once and pressurized to obtain an absorber.

[Evaluation of fecal diffusion prevention]
The stool diffusion prevention property was evaluated by the following method for the absorbers prepared by using the laminated sheets of each of the above Examples and Comparative Examples. In the following method, the stool diffusion prevention property of the absorber is evaluated by the stool diffusion area. As a result, it is judged that the smaller the value of the stool diffusion area, the better the absorber has the liquid diffusion suppressing effect (stool diffusion prevention property). , Highly rated.
First, 10 g of pseudo loose stool was injected into the central portion of the absorber on the skin-facing surface side via a tube. The components of the pseudo loose stool are bentonite 22.5%, poison 530 (40%, manufactured by Kao Corporation) 0.5%, emalgen 130K 0.03% aqueous solution (manufactured by Kao Corporation) 1.5%, ion-exchanged water 75. It was 5.5%, the viscosity was 40 mPa · s (23 ° C., vibration viscometer: manufactured by A & D Co., Ltd., SV-10), and the surface tension was 55 mN / m. The simulated stool was allowed to stand for 30 seconds after injection, and a filter paper and a weight (3.0 kPa) were placed on the simulated stool and pressurized for 2 minutes. Then, the diffusion area of the simulated stool (stool diffusion area) was measured three times by image processing. In the image processing, the diffused state of the simulated stool is photographed with a digital camera, and the image of the 10 cm square plate (100 cm ² ) taken at the same time is captured on the surface sheet using image analysis software (Adobe Photoshop CS5). The diffusion area was calculated by comparing the number of pixels in the portion where the simulated stool was diffused with a plate having a known area. The average value of the measured values was used as the measurement result and is shown in Tables 2 and 3.

Comparative Examples 2 and 5 to 9 in which the ventilation resistance of the laminated sheet is not within the predetermined range, Comparative Example 1 not containing the cellulosic fiber, and the cellulosic fiber layer are laminated on the long-fiber non-woven fabric layer in the form of a dry sheet. In contrast to Comparative Examples 3 and 4 in which the interface between the layers is not in close contact, the laminated sheets of Examples 1 to 14 in which the interface between the long fiber non-woven fabric layer and the cellulosic fiber layer are in close contact have a predetermined range of airflow resistance. Therefore, when the simulated stool was injected, it permeated without spreading on the surface of the laminated sheet, and the stool diffusion area on the surface of the laminated sheet was small, that is, the liquid diffusion was suppressed. Above all, in Examples 8 to 10 using the cellulosic fiber having high fiber roughness, the effect of suppressing the fiber was remarkable.

1 Laminated sheet 20 Long fiber non-woven fabric layer 21 Long fiber 25 Cellulose fiber layer 26 Cellulose fiber 27 Penetrating cellulosic fiber 22 Convex part 23 Concave part 24 Gap 100 diaper 12 Front sheet 13 Back sheet 14 Absorbent 14a Absorbent core 14b Core wrap Sheet 3 Wet Paper Machine 20a Base Sheet 31 Paper Net 33 Suction Box 34 Press Roll 35 Yankee Dryer 36 Winding Roll 10 Molded Sheet 37a, 37b Belt Conveyor

Claims (8)

A laminated sheet having a long-fiber non-woven fabric layer containing hydrophobic long fibers and a cellulosic fiber layer mainly composed of cellulosic fibers provided on one side or both sides of the long-fiber non-woven fabric layer.
The long-fiber non-woven fabric layer has a plurality of concave portions and convex portions on a surface in contact with the cellulose-based fiber layer, and the cellulose-based fiber layer is laminated on the concave portions.
The interface between the long fiber non-woven fabric layer and the cellulosic fiber layer is in close contact with each other.
A laminated sheet having a ventilation resistance as the laminated sheet of 0.001 kPa · s / m or more and 0.08 kPa · s / m or less. The laminated sheet according to claim 1, wherein a part of the cellulosic fibers penetrates the long-fiber non-woven fabric layer and is exposed on one side of the long-fiber non-woven fabric layer. The laminated sheet according to claim 1 or 2, wherein the cellulosic fiber contains a fiber having a fiber roughness of 150 μg / m or more. The concave portion and the convex portion of the long fiber non-woven fabric layer are formed by embossing.
The laminated sheet according to any one of claims 1 to 3, wherein the thickness of the long-fiber non-woven fabric layer in the recess is 90% or less with respect to the average thickness of the long-fiber non-woven fabric layer. The basis weight of the long fiber non-woven fabric layer is 5 to 15 g / m ² .
The laminated sheet according to any one of claims 1 to 4, wherein the cellulosic fiber layer has a basis weight of 0.5 to 10 g / m ^2. An absorbent article in which the laminated sheet according to any one of claims 1 to 5 is used as a core wrap sheet for coating an absorbent core. A papermaking step is provided in which a slurry containing cellulosic fibers is supplied onto a base sheet made of a long-fiber non-woven fabric containing hydrophobic long fibers, and a cellulose-based fiber layer is formed on the base sheet by papermaking.
A method for manufacturing a laminated sheet, wherein the neck-in rate obtained by the following formula (1) is 20% or less.
Neck-in rate (%) = (W _0- W ₁ ) / W ₀ x 100 ... (1)
W ₀ : Length of the base sheet in a direction orthogonal to the transport direction of the base sheet W ₁ : Length of the laminated sheet in the direction orthogonal to the transport direction The method for manufacturing a laminated sheet according to any one of claims 1 to 5.
A papermaking step is provided in which a slurry containing the cellulosic fibers is supplied onto a base sheet made of a long fiber non-woven fabric containing hydrophobic long fibers, and the cellulosic fiber layer is formed on the base sheet by papermaking. A method of manufacturing a laminated sheet.

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