TWI856254B - Laminated nonwovens and sanitary materials - Google Patents

Abstract

The subject of the present invention is to provide a laminated nonwoven fabric which has sufficient quick-drying property and superior water absorption speed in order to maintain the comfort of a component using a nonwoven fabric for sanitary materials. The present invention is a laminated nonwoven fabric which is formed by laminating nonwoven fabric layers composed of thermoplastic resin fibers, wherein in the nonwoven fabric layer (A) having the smallest average single fiber diameter, the inter-fiber space size Ra (μm) calculated by the following formula (1) is less than 200 μm. Where, Ta: thickness of nonwoven fabric layer (A) (μm) da: fiber density of thermoplastic resin fiber constituting nonwoven fabric layer (A) (dtex) Wa: basis weight of nonwoven fabric layer (A) (g/ ^m2 ) Da: average single fiber diameter of thermoplastic resin fiber constituting nonwoven fabric layer (A) (μm)

Description

Laminated nonwovens and sanitary materials

The present invention relates to a laminated nonwoven fabric which is particularly suitable for use as a sanitary material and a sanitary material using the laminated nonwoven fabric.

Generally speaking, for sanitary materials such as diapers, sanitary napkins, and masks, the key to comfort is to quickly absorb moisture such as urine or sweat and keep the surface of the component dry.

Therefore, components that come into direct contact with the skin are required to have both "water absorption" to quickly absorb water and "quick-drying" to allow the absorbed water to migrate from the outermost layer to leave the surface dry.

As is known, various non-woven fabrics that have been subjected to hydrophilic treatment are widely used as surface components. Although these can induce moisture from the outermost layer to the inner non-woven fabric or absorbent, the moisture tends to remain on the outermost layer, and the "quick-drying property" is deteriorated.

Regarding this topic, Patent Document 1 proposes a nonwoven fabric in which a fiber layer (skin-facing side) composed of fine-fiber fibers and a fiber layer composed of coarse-fiber fibers are intertwined at a portion of the interface. In addition, Patent Document 2 proposes a sheet material in which the average fiber non-occupied space is different due to the difference in the mixing ratio of multiple fibers and the fiber diameter, and the average fiber non-occupied space of the first layer in contact with the skin is larger than that of the layers other than the first layer. [Prior art document] [Patent document]

Patent document 1: Japanese Patent Publication No. 7-042057 Patent document 2: Japanese Patent Publication No. 7-178133

(Invent the problem you want to solve)

However, it is difficult to simultaneously achieve "quick-drying property" and "water absorption property" in the technology of Patent Document 1.

On the other hand, the technology of Patent Document 2 states that by providing a difference in the volume of spaces other than fibers between the layers, the difference in capillary effect can be used to induce the water absorbed by the first layer to the second layer (the layer opposite to the skin surface). However, the technology of Patent Document 2 is not sufficient in terms of "quick drying".

Therefore, the object of the present invention is to provide a laminated nonwoven fabric which has sufficient quick-drying properties and excellent water absorption in order to maintain the comfort of the components using the sanitary nonwoven fabric. (Technical means for solving the problem)

The inventors of this case discovered that in the technology of Patent Document 1, since the fiber layer composed of fine-fine fibers on the skin surface side is densely structured relative to the layers outside it, water is easily retained in the fiber layer on the skin surface side, making it difficult to obtain "quick-drying properties"; furthermore, since the dense fiber layer on the skin surface side reduces liquid permeability, it is impossible to quickly absorb water, making it difficult to obtain "water absorption properties".

Furthermore, the inventors of this case discovered that the average fiber non-occupied spaces disclosed in Patent Document 2 represent the total volume of space occupied by spaces other than fibers, and therefore are not an indicator of the size of the spaces between fibers that are important for capillary force. Even if there are differences between layers, it does not mean that there are differences in capillary force. In particular, in Patent Document 2, since the size of the spaces between fibers in the non-skin layer is larger, the capillary force cannot be fully exerted, the effect of water migration from the skin surface is limited, and the "quick-drying property" is not sufficient.

Then, in order to achieve the above-mentioned purpose, the inventors of the present case found through intensive research that in a laminated nonwoven fabric, by controlling the size of the inter-fiber gaps taking into account the fiber diameter in addition to the basis weight and thickness in a specific nonwoven fabric layer within a specific range, a laminated nonwoven fabric with sufficient water absorption and quick-drying properties for use as a nonwoven fabric for sanitary materials can be obtained.

The present invention is accomplished based on these insights, and according to the present invention, the following inventions are provided.

The present invention is a laminated nonwoven fabric, which is formed by laminating nonwoven fabric layers composed of thermoplastic resin fibers. Among the nonwoven fabric layers, in the nonwoven fabric layer (A) having the smallest average single fiber diameter, the inter-fiber gap size Ra (μm) calculated according to the following formula (1) is less than 200 μm. Ra=(100 Ta da)/(Wa Da)-Da ... Formula (1) Wherein, Ta: thickness of nonwoven fabric layer (A) (μm) da: fiber density of thermoplastic resin fiber constituting nonwoven fabric layer (A) (dtex) Wa: basis weight of nonwoven fabric layer (A) (g/ ^m2 ) Da: average single fiber diameter of thermoplastic resin fiber constituting nonwoven fabric layer (A) (μm)

Furthermore, the present invention is a sanitary material, at least a part of which is composed of the laminated nonwoven fabric of the present invention. (Compared with the efficacy of the prior art)

According to the present invention, a laminated nonwoven fabric having sufficient quick-drying property and superior water absorption speed can be obtained for use as a nonwoven fabric for sanitary materials.

The present invention is described in detail below. However, the present invention is not limited to the scope of the following description without exceeding the gist of the invention.

[Thermoplastic resin fiber] First, the laminated nonwoven fabric of the present invention is formed by laminating nonwoven fabric layers composed of thermoplastic resin fiber.

The "thermoplastic resin fiber" in the present invention refers to a fiber composed of a thermoplastic resin. The thermoplastic resin may be one type or may be composed of a plurality of thermoplastic resins.

Examples of thermoplastic resins used in the thermoplastic resin fiber of the present invention include the following: Aromatic polyester polymers such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyhexamethylene terephthalate, and the like, and copolymers thereof; Aliphatic polyester polymers such as polylactic acid, polyethylene succinate, polybutylene succinate, polybutylene succinate adipate, polyhydroxybutyrate-polyhydroxyvalerate copolymer, polycaprolactone, and the like, and copolymers thereof; Aliphatic polyamide polymers such as polyamide 6, polyamide 66, polyamide 610, polyamide 10, polyamide 12, polyamide 6-12 and their copolymers; Polyolefin polymers such as polypropylene, polyethylene, polybutene, polymethylpentene and their copolymers; Water-insoluble ethylene-vinyl alcohol copolymer polymers containing 25 mol% to 70 mol% of ethylene units; Polystyrene, polydiene, chlorine, polyolefin, polyester, polyurethane, polyamide, fluorine-based elastic polymers, etc.

Furthermore, the thermoplastic resin may also contain various additives such as inorganic substances such as titanium oxide, silicon dioxide, barium oxide, coloring agents such as carbon black, dyes or pigments, flame retardants, fluorescent whitening agents, antioxidants, or ultraviolet absorbers.

Furthermore, the thermoplastic resins constituting the thermoplastic resin fibers between the nonwoven fabric layers may be the same or different.

The thermoplastic resin fiber of the present invention may be a composite fiber of two or more resins in addition to a single-component fiber. When the thermoplastic resin fiber is a composite fiber, there is no particular limitation on the premise that the effect of the present invention is not impaired, and the fiber may be appropriately selected from a core-sheath type, an island-shaped fiber, a side-by-side type, an eccentric core-sheath type, etc. In addition, the fiber may be a torn fiber type composite fiber in which a part or the whole of the fiber is divided into a plurality of fibers from a single fiber.

The cross-sectional shape of the thermoplastic resin fiber of the present invention is not particularly limited without compromising the effects of the present invention. In addition to a circular cross-sectional shape, it can also be a triangular, flat, hexagonal, hollow, or other irregular cross-sectional shape. When the laminated nonwoven fabric of the present invention is used in sanitary materials, a circular cross-sectional shape is preferred in terms of high productivity and superior softness.

[Laminar interface of laminated nonwoven fabric] The laminated interface used for a specific nonwoven fabric layer in the laminated nonwoven fabric of the present invention is described. The laminated interface in the laminated nonwoven fabric of the present invention is specified according to the following steps.

(Specific steps for laminated interfaces) Step 1: Take a 5cm×5cm sample piece from the laminated nonwoven fabric. At this time, avoid the part with poor uniformity and thin thickness.

Step 2: Take a three-dimensional image of the sample obtained in step 1 using a high-resolution three-dimensional X-ray microscope. The resolution of the measurement can be within the range that can specify the fiber diameter of each non-woven fabric layer, and is preferably set to be less than 1.0μm/voxel. In the case of embossing the laminated non-woven fabric, the image is taken in such a way that the center point between the embossed points, i.e., the center of the convex portion left by the embossing process, is included in the shooting range of the X-ray CT image.

Step 3: Extract a 0.5mm×0.5mm area from the 3D image taken in step 2 as the analysis target area. In the case of embossing the laminated nonwoven fabric, the analysis target area is extracted in such a way that it includes the center point between the embossing points.

Step 4: For the analysis target area extracted in step 3, parallel slice (cross-section) images are created at intervals of 1 voxel in a direction perpendicular to the thickness direction of the laminated non-woven fabric.

Step 5: Analyze the fiber diameters of all fibers contained in each slice image obtained in step 4, and calculate the average value as the provisional average fiber diameter.

Step 6: Plot a graph with the position of each slice image obtained in step 4 in the thickness direction of the laminated nonwoven fabric as the x-axis (in μm) and the provisional average fiber diameter of each slice image obtained in step 5 as the y-axis (in μm).

Step 7: In the graph obtained in step 6, the data of the change rate Δy/Δx of the y-axis value relative to the x-axis value of 15 consecutive voxels are calculated by the least square method, and the interval on the x-axis where the absolute value is greater than 0.30 is specified as the position of the layer interface between the non-woven fabric layers.

[Nonwoven fabric layer (A)] The nonwoven fabric layer (A) in the laminated nonwoven fabric of the present invention is defined as the nonwoven fabric layer having the smallest average single fiber diameter among the nonwoven fabric layers constituting the laminated nonwoven fabric.

The average single fiber diameter of each nonwoven fabric layer is obtained as follows.

(Measurement steps of the average single fiber diameter of the nonwoven fabric layer) Step 1: Use a scanning electron microscope (SEM) to photograph the cross section in the thickness direction of the laminated nonwoven fabric at a magnification that allows the entire thickness direction of the laminated nonwoven fabric to be included in the photographing range.

Step 2: Apply the position information of the laminate interface obtained by the "laminated interface identification step" to the cross-sectional photograph obtained in step 1. The interval on the x-axis where the absolute value of Δy/Δx in step 7 of the "laminated interface identification step" becomes 0.30 or more is set as the laminate interface interval, and the interval divided by the same laminate interface interval is set as the analysis interval for each non-woven fabric layer.

Step 3: Using the image analysis software, measure the area Af (μm ² ) formed by the cross-sectional profile of the single fiber in the analysis interval specified in step 2, and calculate the diameter of a perfect circle with the same area as the area Af. This is done by measuring 20 single fibers randomly extracted from the same analysis interval, and the average is calculated, with the unit set to μm, and the second decimal place is rounded off to the nearest integer, which is the average single fiber diameter.

The average single fiber diameter Da of the thermoplastic resin fiber constituting the nonwoven fabric layer (A) is preferably 20.0 μm or less. By setting Da to 20.0 μm or less, more preferably 15.0 μm or less, the inter-fiber space size Ra of the nonwoven fabric layer (A) described below can be effectively reduced, and better capillary force can be obtained. In addition, Da is preferably 2.0 μm or more. By setting Da to 2.0 μm or more, the inter-fiber space size Ra of the nonwoven fabric layer (A) can be suppressed from being extremely reduced, and the reduction of liquid permeability can be suppressed.

The laminated nonwoven fabric of the present invention has a nonwoven fabric layer (A) in which the inter-fiber space size Ra calculated by the following formula (1) is less than 200 μm. Ra=(100 Ta da)/(Wa Da)-Da ... Formula (1) Wherein, Ta: thickness of nonwoven fabric layer (A) (μm) da: fiber density of thermoplastic resin fiber constituting nonwoven fabric layer (A) (dtex) Wa: estimated basis weight of nonwoven fabric layer (A) (g/ ^m2 ) Da: average single fiber diameter of thermoplastic resin fiber constituting nonwoven fabric layer (A) (μm)

The thickness of each nonwoven fabric layer is obtained as follows.

(Nonwoven fabric layer thickness measurement step) Step 1: Add the average single fiber diameters of the nonwoven fabric layer to be measured and the other nonwoven fabric layers stacked thereon obtained in the "nonwoven fabric layer average single fiber diameter measurement step" and divide by 2 to calculate the average fiber diameter of the two layers. When other nonwoven fabric layers are stacked on the other side of the nonwoven fabric layer to be measured, similarly, add the average single fiber diameters between the other nonwoven fabric layers and divide by 2 to calculate the average fiber diameter of the two layers.

Step 2: In the graph obtained in step 6 of "step of specifying the lamination interface", in the lamination interface region between the nonwoven fabric layer to be measured for thickness and other nonwoven fabric layers laminated thereon, specify the x coordinate where y is the average value of the fiber diameters of the two layers calculated in step 1.

Step 3: When other nonwoven fabric layers are stacked on both sides of the nonwoven fabric layer to be measured, the distance between the x-coordinates when the average value of the fiber diameters of the two stacked layers is calculated in the stacked interface region on both sides is used as the thickness of the nonwoven fabric layer to be measured. When only one side of the nonwoven fabric layer to be measured is laminated with another nonwoven fabric layer, the distance between the x-coordinate of the average value of the fiber diameters of the two layers in the laminated interface region and the x-coordinate of the surface exposed on the other side of the nonwoven fabric layer to be measured is calculated as the thickness of the nonwoven fabric layer to be measured.

The thickness Tt of the laminated nonwoven fabric can be obtained by calculating the distance between the x-coordinates of the two side surfaces of the laminated nonwoven fabric in step 3 of the "step of measuring the thickness of the nonwoven fabric layer".

The fiber density of the thermoplastic resin fiber constituting the nonwoven fabric layer is calculated by rounding off the second decimal place of the value calculated by the following formula using the average single fiber diameter of the thermoplastic resin fiber and the density of the thermoplastic resin fiber measured in the "measurement step of the average single fiber diameter of the nonwoven fabric layer". d=(π ρ D ² )/400 Wherein, d: fiber density of the thermoplastic resin fiber constituting the nonwoven fabric layer (dtex) ρ: density of the thermoplastic resin fiber constituting the nonwoven fabric layer ρ (g/cm ³ ) D: average single fiber diameter of the thermoplastic resin fiber constituting the nonwoven fabric layer (μm).

The density ρ of thermoplastic resin fiber is measured according to "8.17.2 Density gradient tube method" of JIS L1013:2010 "Test methods for chemical fiber single yarn". A density gradient tube with an appropriately adjusted density range is prepared, and the fiber density (g/cm ³ ) is measured to the third decimal place for a fiber piece of about 0.1g taken from the non-woven fabric layer. The same operation is performed on 5 different samples randomly taken from the non-woven fabric layer, and the average of the results is calculated. The value rounded to the third decimal place is the density ρ (g/cm ³ ) of the first thermoplastic fiber.

In addition, the estimated basis weight (g/m ² ) of the nonwoven fabric layer is obtained as follows.

First, the basis weight Wt (g/m ² ) of the laminated nonwoven fabric is determined according to "6.2 Mass per unit area" of JIS L1913:2010 "General nonwoven fabric test methods". Specifically, 3 test pieces of 20cm×25cm in size are cut from the laminated nonwoven fabric for every 1m of the sample width, and the respective masses (g) under the standard state are weighed separately. The value of the mass per 1m ² calculated from the average value is rounded to the second decimal place as the basis weight Wt (g/m ² ) of the laminated nonwoven fabric.

Next, using the thickness T of the nonwoven fabric layer and the thickness Tt of the laminated nonwoven fabric obtained in the above steps, the value calculated by the following formula is rounded to the second decimal place as the estimated basis weight W (g/m ² ) of the nonwoven fabric layer. W=W×T/Tt …Formula

The inter-fiber space size shown in formula (1) represents the value of the length of one side of the space defined by the fibers when the fibers contained in the non-woven fabric layer are arranged in a regular grid pattern. The smaller the inter-fiber space size, the stronger the capillary force, which can be considered to increase the water suction force.

In the laminated nonwoven fabric of the present invention, by setting the inter-fiber space size Ra of the nonwoven fabric layer (A) having the smallest average single fiber diameter to be less than 200 μm, preferably less than 100 μm, and more preferably less than 80 μm, when liquid is dripped onto the outermost surface of the laminated nonwoven fabric, the capillary force of the nonwoven fabric layer (A) can be increased, so that more liquid can be transferred to the nonwoven fabric layer (A), and good quick-drying properties can be exerted.

In addition, when the inter-fiber space size Ra is set to 30 μm or more, it is better in terms of ensuring a certain liquid permeability and water absorption.

The inter-fiber space size Ra can be controlled by controlling the average single fiber diameter Da of the thermoplastic resin fibers constituting the non-woven fabric layer.

The thickness of the nonwoven fabric layer (A) is preferably set to be 100 μm or more. By setting the thickness of the nonwoven fabric layer (A) to be 100 μm or more, and more preferably 120 μm or more, more liquid absorbed by the nonwoven fabric layer (A) can be retained in the nonwoven fabric layer (A), and the water distribution ratio described later in the surface of the nonwoven fabric layer (A) side can be increased.

On the other hand, the thickness of the nonwoven fabric layer (A) is preferably 1000 μm or less. By setting the thickness of the nonwoven fabric layer (A) to 1000 μm or less, it is possible to prevent the liquid from being retained inside the nonwoven fabric layer (A) and suppress the migration of the liquid between the nonwoven fabric layers.

[Nonwoven fabric layer (B)] The nonwoven fabric layer (B) in the laminated stretch nonwoven fabric of the present invention is defined as a nonwoven fabric layer laminated with the nonwoven fabric layer (A).

In the laminated nonwoven fabric of the present invention, for at least one layer of the nonwoven fabric layer (B) laminated with the nonwoven fabric layer (A) (including the nonwoven fabric layer (B) when only one layer of the nonwoven fabric layer (A) is laminated with the nonwoven fabric layer (B)), it is preferred that the ratio Rb/Ra of the inter-fiber gap size Rb (μm) calculated according to the following formula (2) to the above Ra (μm) is 1.1 times or more. Rb=(100 Tb db)/(Wb Db)-Db ...Formula (2) Wherein, Tb: thickness of nonwoven fabric layer (B) (μm) db: fiber density of thermoplastic resin fiber constituting nonwoven fabric layer (B) (dtex) Wb: estimated basis weight of nonwoven fabric layer (B) (g/ ^m2 ) Db: average single fiber diameter of thermoplastic resin fiber constituting nonwoven fabric layer (B) (μm)

In addition, Tb (μm), db (dtex), Wb (g/m ² ), and Db (μm) in formula (2) are obtained by using the thickness T of the nonwoven fabric layer, the fiber density d of the thermoplastic resin fiber constituting the nonwoven fabric layer, the estimated basis weight W of the nonwoven fabric layer, and the average single fiber diameter D of the thermoplastic resin fiber constituting the nonwoven fabric layer as described above.

By setting Rb/Ra to 1.1 times or more, preferably 1.2 times or more, and more preferably 1.5 times or more, the large difference in capillary force between the non-woven fabric layer (A) and the non-woven fabric layer (B) can be utilized to efficiently transfer moisture to the non-woven fabric layer (A), thereby improving quick-drying properties.

On the other hand, when the ratio of Rb to Ra gradually increases, the ratio of inter-fiber spaces in the nonwoven fabric layer (B) also increases. From the perspective of suppressing the basis weight unevenness that occurs at this time and suppressing the strength reduction caused by this basis weight unevenness, Rb/Ra is preferably less than 10.0 times.

The inter-fiber space size Rb of the nonwoven fabric layer (B) is preferably 100 μm or more. By setting Rb to 100 μm or more, more preferably 120 μm or more, the amount of liquid remaining in the nonwoven fabric layer (B) is reduced due to good liquid permeability, and quick drying can be achieved.

The inter-fiber space size Rb of the non-woven fabric layer (B) is preferably 500 μm or less. By setting Rb to 500 μm or less, the liquid that has migrated to the non-woven fabric layer (A) can be prevented from seeping out when a load is applied to the laminated non-woven fabric, and a dry surface can be maintained.

When the inter-fiber gap size Rb (μm) of the non-woven fabric layer (B) is controlled to be within the above range, it is preferred that the average single fiber diameter Db of the thermoplastic resin fibers constituting the non-woven fabric layer (B) is within the range of 15.0 μm to 30.0 μm.

The thickness of the nonwoven fabric layer (B) is preferably in the range of 100 to 1000 μm. By setting the thickness of the nonwoven fabric layer (B) to be greater than 100 μm, it is possible to suppress the situation where a portion of the water retained by the nonwoven fabric layer (A) permeates out, thereby increasing the water distribution ratio described later. In addition, by setting the thickness of the nonwoven fabric layer (B) to be less than 1000 μm, the liquid absorbed by the nonwoven fabric layer (B) can quickly permeate into the nonwoven fabric layer (A).

[Laminated nonwoven fabric] The laminated nonwoven fabric of the present invention is preferably such that when physiological saline is absorbed on both sides thereof according to the following steps, at least one of the four surfaces, namely, the absorption surface on which physiological saline is absorbed and the surface on the opposite side thereof, has a water distribution ratio defined by the following formula (3) of 40% or less.

(Measurement steps of water distribution ratio) Step 1: Cut 5cm of non-woven fabric from the laminate 5cm sample.

Step 2: Prepare 2 pieces of filter paper according to JIS P3801 and cut them into 5 cm thick pieces for each measurement. 5cm, measure the mass separately.

Step 3: Drop 0.250±0.005mL of physiological saline onto the polypropylene film. At this time, measure the mass of the physiological saline dropped in advance.

Step 4: Place a piece of non-woven fabric on the dripped saline solution with the absorption side facing downwards and keep it there for 1 minute.

Step 5: After the step 4 is maintained, the laminated nonwoven fabric is removed from the polypropylene film and placed on the first sheet of filter paper with the absorbent surface facing upward, and then the second sheet of filter paper is quickly placed thereon.

Step 6: Place a 125g weight on the second filter paper at a pressure of 5g/ ^cm2 and keep it there for 1 minute.

Step 7: After the holding in step 6, remove the weight, measure the mass of each filter paper, and calculate the mass increase of each filter paper.

Step 8: Calculate the water distribution ratio of each surface of the above-mentioned multilayer nonwoven fabric using the following formula. Water distribution ratio (%) = 100 W1/W0 Where, W0: The mass of physiological saline dripped in the above step 3 (g) W1: The mass increase of the filter paper contacting its surface in the above step 7 (g)

The lower the water distribution ratio obtained in this step, the less liquid is retained on the surface. In other words, if the water distribution ratio of the surface contacting the skin is low, even if it absorbs liquid, it will still feel dry when it touches.

In the laminated nonwoven fabric of the present invention, by making the water distribution ratio of at least one surface among the above four surfaces less than 40%, preferably less than 30%, and more preferably less than 20%, the amount of moisture retained by the surface is small, and a dry surface can be efficiently maintained.

In the laminated nonwoven fabric of the present invention, as a mode for achieving the above-mentioned surface water distribution ratio, it is preferable that the nonwoven fabric layer (B) is laminated on the outermost surface of at least one side. That is, since the nonwoven fabric layer (B) is defined as a nonwoven fabric layer laminated in contact with the nonwoven fabric layer (A) as described above, the laminated nonwoven fabric of this preferred mode has a laminated structure of at least one side being nonwoven fabric layer (B)/nonwoven fabric layer (A)… . Furthermore, as described above, since the nonwoven fabric layer (A) is defined as the nonwoven fabric layer having the smallest average single fiber diameter among the nonwoven fabric layers constituting the laminated nonwoven fabric, when the liquid is absorbed by the outermost surface of the nonwoven fabric layer (B) having a larger average single fiber diameter, the liquid quickly moves to the nonwoven fabric layer (A) having the inter-fiber space size controlled to be very small as described above, and therefore the water distribution ratio of the outermost surface of the nonwoven fabric layer (B) becomes smaller, thereby achieving quick-drying properties.

In addition, the laminated nonwoven fabric of the present invention preferably has a water distribution ratio of 50% or more on the opposite side of the surface with a water distribution ratio of less than 40%. By setting the water distribution ratio to 50% or more, preferably 60% or more, the absorbed liquid will not be retained inside the laminated nonwoven fabric, and the liquid can be smoothly transferred from the surface that has absorbed the liquid to the other side.

In the laminated nonwoven fabric of the present invention, in order to control the water distribution ratio of the surface opposite to the surface absorbing liquid to the above range, it is preferred to arrange the nonwoven fabric layer (A) with high capillary force on one side of the surface.

The laminated nonwoven fabric of the present invention preferably has a water absorption rate measured on at least one surface of 20 seconds or less.

The water absorption rate referred to herein is measured according to "7.1.1 Drop method" of "Test method for water absorption of fiber products" in JIS L1907:2010. Drop one drop of water on the laminated nonwoven fabric, and measure the time from the absorption to the disappearance of the mirror reflection on the surface. This measurement is performed at 10 different locations and the simple average of these values is calculated. The unit is set to seconds, and the value rounded to the first decimal place is used as the water absorption rate in the present invention.

When the water absorption speed is 20 seconds or less, and more preferably 10 seconds or less, it indicates that the performance of removing water attached to the surface is good.

The basis weight of the laminated nonwoven fabric of the present invention is preferably set to 10-100 g/m ² .

By setting the basis weight to preferably 10 g/m ² or more, more preferably 13 g/m ² or more, and even more preferably 15 g/m ² or more, a laminated nonwoven fabric having a mechanical strength sufficient for practical use can be obtained. On the other hand, by setting the basis weight to preferably 100 g/m ² or less, and more preferably 50 g/m ² or less, a laminated nonwoven fabric having a suitable softness suitable for use as a nonwoven fabric for sanitary materials can be produced.

The laminated nonwoven fabric of the present invention is preferably an integrated nonwoven fabric layer. Here, the so-called integration means that the nonwoven fabric layers are connected by intertwining fibers, fixing by adhesives and other components, and fusing and bonding the thermoplastic resins constituting the layers.

The laminated nonwoven fabric of the present invention is intended to further enhance water absorption and may also be provided with a hydrophilic agent.

[Hygienic material] The hygienic material of the present invention is at least partially composed of the laminated nonwoven fabric of the present invention, and therefore has excellent water absorption and quick-drying properties.

The sanitary material of the present invention can be used for health-related purposes such as medical treatment and care. The sanitary material of the present invention can be mainly used for disposable items, such as diapers, sanitary napkins, gauze, bandages, masks, gloves, bandages, etc.

In particular, in the case of paper diapers, it can be used as a structural member of the surface sheet, back sheet, side folds, etc.

The surface sheet of the sanitary diaper of the present invention is preferably composed of the laminated nonwoven fabric of the present invention. When the laminated nonwoven fabric of the present invention is used as the surface sheet of the diaper, if the nonwoven fabric layer (B) is arranged as the skin side of the surface sheet, the urine excreted can be quickly absorbed and moved to the nonwoven fabric layer (A), and the surface of the surface sheet can be kept dry.

In addition, the diaper of the sanitary material of the present invention preferably has at least a portion of the waist portion formed of the laminated nonwoven fabric of the present invention. When the laminated nonwoven fabric of the present invention is used as a portion of the waist portion of the diaper, if the nonwoven fabric layer (B) is disposed as the skin side of the waist portion of the diaper, sweat can be quickly absorbed and moved to the nonwoven fabric layer (A), thereby keeping the surface of the waist portion dry.

Furthermore, the sanitary material of the present invention is also suitable for use as a mask. In the mask of the sanitary material of the present invention, it is preferred that the inner surface layer is composed of the laminated nonwoven fabric of the present invention. The so-called inner surface layer in the present invention refers to the layer disposed closest to the mouth in the face body covering the mouth. If the laminated nonwoven fabric of the present invention is used in a manner in which the nonwoven fabric layer (B) is disposed as the skin side, even if sweat or exhaled breath condenses and moisture adheres to the skin side, it is immediately absorbed into the interior of the laminated nonwoven fabric, and the skin surface can be kept dry, so it can be used without discomfort when worn.

[Manufacturing method of laminated nonwoven fabric] Next, the preferred method of manufacturing the laminated nonwoven fabric of the present invention is described in detail.

The manufacturing method of the nonwoven fabric layer (A) and the nonwoven fabric layer (B) constituting the multilayer nonwoven fabric of the present invention can be selected from known manufacturing methods such as a spunbonding method, a melt-blowing method, and a staple fiber carding machine method.

Among them, the spunbond method can be cited as a preferred method due to its superior productivity.

The following describes a preferred embodiment of manufacturing the laminated nonwoven fabric of the present invention by a spunbonding method, but the present invention is not limited thereto.

The so-called spinning bonding method is a method of manufacturing non-woven fabrics in which the thermoplastic resin, which is the raw material, is melted, spun from a spinning nozzle, and then the filaments obtained by cooling and solidification are pulled and stretched by a jet, captured on a moving net, and formed into a non-woven fiber net, which requires a step of thermal bonding.

The spinning nozzle or the jet used may be in various shapes such as round or rectangular. Among them, the combination of a rectangular nozzle and a rectangular jet is the best form from the viewpoint of using less compressed gas and preventing the yarns from fusing or scratching each other.

The spinning temperature in the present invention is preferably set to be above (melting temperature of the thermoplastic resin as raw material + 10°C) and below (melting temperature of the thermoplastic resin as raw material + 100°C). By setting the spinning temperature within the above range, a stable melting state can be achieved, thereby obtaining excellent spinning stability.

Furthermore, when manufacturing the nonwoven fabric layer (A), the average inter-fiber space can be reduced by reducing the fiber diameter. Therefore, in order to stably manufacture fine fibers, it is preferred that the melt viscosity of the polymer used in the nonwoven fabric layer (A) be set to 100 Pa‧s or less, more preferably 50 Pa‧s or less.

The melt viscosity of the polymer here is measured by placing the polymer chips in a vacuum dryer to a moisture content of less than 200 ppm and changing the strain rate stepwise. The measurement temperature is set to the value at the strain rate of 1216 s ^-1 when the spinning temperature is the same.

The spun yarn is then cooled. Methods for cooling the spun yarn include, for example, a method of forcibly adsorbing cold air to the yarn, a method of naturally cooling the yarn by the ambient temperature around the yarn, and a method of adjusting the distance between the spinning nozzle and the ejector. In addition, a method combining these methods can be adopted. In addition, the cooling conditions can be appropriately adjusted and adopted in consideration of the discharge amount per single hole of the spinning nozzle, the temperature of the yarn, and the ambient temperature.

Then, the cooled and solidified filament is pulled and stretched by compressed gas ejected from the ejector.

In the laminated nonwoven fabric of the present invention, the average inter-fiber space size of the nonwoven fabric layer (A) and the nonwoven fabric layer (B) can be controlled by the diameter of the constituent fibers.

The fiber diameter is determined by the discharge amount per discharge hole of the spinning nozzle and the pulling speed, that is, the spinning speed. Therefore, it is better to determine the discharge amount and spinning speed in a way that the diameter can be controlled to obtain the required inter-fiber space size.

The spinning speed is preferably 2000 m/min or more. By setting the spinning speed to 2000 m/min or more, more preferably 3000 m/min or more, high productivity is achieved, and the fiber orientation crystallization proceeds, thereby obtaining a long fiber with high strength.

The long fiber strands stretched by the pulling are captured by the moving net and made into sheets, which are then subjected to the step of thermal bonding.

The laminated nonwoven fabric of the present invention is formed by laminating nonwoven fabric layers. As a method for laminating nonwoven fabric layers, for example, the following methods can be adopted: as described above, thermoplastic resin fibers are captured on a capture net by a spunbonding method, and then the thermoplastic resin fibers are captured on the obtained nonwoven fabric layer by a spunbonding method to obtain a subsequent nonwoven fabric layer, and the capture is continuously performed on a production line to perform lamination integration; two or more nonwoven fabric layers obtained separately are overlapped outside a production line and laminated by heat pressing, etc. Among them, in terms of superior productivity, the best method is to continuously capture the next non-woven fabric layer on the non-woven fabric layer on the production line and integrate the layers by thermal bonding.

As a method for integrating nonwoven fabric layers by heat bonding to form the laminated nonwoven fabric of the present invention, a heat bonding method using the following various rollers can be adopted: a heat embossing roller with engravings (concave and convex parts) applied to the surfaces of an upper and lower pair of rollers; a heat embossing roller composed of a combination of a roller with a flat (smooth) surface and a roller with engravings (concave and convex parts) applied to the surface of the other roller; a heat embossing roller composed of a combination of an upper and lower pair of flat (smooth) rollers; or a heat embossing method such as ultrasonic bonding by heat melting by ultrasonic vibration of a welding head. Furthermore, as a method of laminating and integrating the laminated nonwoven fabric of the present invention by thermal pressure bonding, there can be exemplified a so-called air-through method, which is a method of blowing hot air.

Among them, the method of heat bonding by a pair of upper and lower heat rollers is to compress the laminated nonwoven fabric layer while bonding it, thereby making the nonwoven fabric layer (A) denser and reducing the size of the gaps between the fibers, so it is better.

When the laminated nonwoven fabric of the present invention is manufactured by heat pressing with hot rollers, the linear pressure applied to the laminated nonwoven fabric between the rollers is preferably set to 100 N/cm or more, because the nonwoven fabric layer (A) can be sufficiently densified.

Furthermore, in the laminated nonwoven fabric, it is preferred to set the surface of the nonwoven fabric layer (B) closer to the nonwoven fabric layer (A) as a flat roller and the surface on the opposite side as a carved hot embossing roller for processing. By adopting such a combination of rollers, since the nonwoven fabric layer (B) is not easily compressed relative to the nonwoven fabric layer (A), the difference in the size of the gaps between the fibers of the nonwoven fabric layer (A) and the nonwoven fabric layer (B) can be ensured to be larger.

The laminated nonwoven fabric of the present invention can also be provided with a hydrophilic agent before being rolled up. As a method of providing the laminated nonwoven fabric with a hydrophilic agent, for example, coating by a contacting rubber roller or a sprayer, or dipping, etc., can be cited. In terms of uniformity or ease of controlling the amount of adhesion, coating by a contacting rubber roller is preferred. [Example]

Next, the present invention is described in detail based on the embodiments. However, the present invention is not limited to these embodiments. In the measurement of various physical properties, those not particularly described are measured according to the above-mentioned methods.

(1) Identification of the laminated interface The laminated interface of the laminated nonwoven fabric was identified by the above-mentioned "laminated interface identification step". In addition, "nano3DX" manufactured by RIGAKU Co., Ltd. was used as a high-resolution three-dimensional X-ray microscope. In addition, the resolution was set to 0.6μm/voxel.

(2) Average single fiber diameter The average single fiber diameter of each nonwoven fabric layer was measured by the above-mentioned "measurement step of the average single fiber diameter of the nonwoven fabric layer". In addition, "S-5500" manufactured by Hitachi High-Tech Co., Ltd. was used as a scanning electron microscope (SEM), and "WinROOF2015" manufactured by Mitani Shoji Co., Ltd. was used as an image analysis software.

(3) Average single fiber diameter during the manufacturing process of laminated nonwoven fabrics For each thermoplastic resin fiber, fiber samples were randomly collected from the nonwoven web captured on the net, and the cross-section of the fiber was imaged at a magnification that allowed one fiber to be observed using a scanning electron microscope "S-5500" manufactured by Hitachi Advanced Technologies Co., Ltd. Subsequently, "WinROOF2015" manufactured by Mitani Shoji Co., Ltd. was used as the image analysis software to perform the measurement as described above.

By measuring the average single fiber diameter during the manufacturing process of the laminated nonwoven fabric, it was confirmed that the average single fiber diameter obtained in the present embodiment and the comparative example was the same as that obtained by the above-mentioned "step of measuring the average single fiber diameter of the nonwoven fabric layer".

(4) Thickness The thickness of the laminated nonwoven fabric and each nonwoven fabric layer is measured by the above-mentioned "nonwoven fabric layer thickness measurement step".

(5) Thickness measured by a simple method For a cross section perpendicular to the mechanical direction of the laminated nonwoven fabric, an image was taken at a magnification that allowed the thickness to be observed using a scanning electron microscope ("S-5500" manufactured by Hitachi Advanced Technologies Co., Ltd.). The thickness of the laminated nonwoven fabric and each nonwoven fabric layer was measured based on the image taken.

By measuring the thickness of the laminated nonwoven fabric and each nonwoven fabric layer by a simple method, it can be confirmed that the thickness obtained in this embodiment and the comparative example is the same as that measured by the above-mentioned "step of measuring the thickness of the nonwoven fabric layer".

(6) The inter-fiber gap size of the non-woven fabric layer can be calculated using the following formula. R = (100 T d)/(W D)-D Wherein, T: thickness of the nonwoven fabric layer (μm). Measured by the above (4). d: fiber density of the thermoplastic resin fiber constituting the nonwoven fabric layer (dtex). Measured by the above definition of d. W: estimated basis weight of the nonwoven fabric layer (g/ ^m2 ). Measured by the above definition of W. Moreover, in this embodiment and comparative example, it can be confirmed that there is no difference in basis weight with the nonwoven fiber web layer described later. D: average single fiber diameter of the thermoplastic resin fiber constituting the nonwoven fabric layer (μm). Measured by the above (2).

(7) Water distribution ratio The water distribution ratios of the two surfaces of the laminated nonwoven fabric are measured by the above-mentioned "water distribution ratio measurement step". In the present embodiment and comparative example, the surface where the nonwoven fabric layer (B) is arranged on the outermost surface is set as the "absorption surface" in step 4 of the "water distribution ratio measurement step". In addition, the number of samples is set to 5, and the sum average is obtained, and the first decimal place is rounded off.

(8) Water absorption rate The water absorption rate is measured according to "7.1.1 Drop method" of "Test method for water absorption of fiber products" in JIS L1907:2010. Drop a drop of water on the laminated nonwoven fabric and measure the time from the time when it is absorbed and the mirror reflection on the surface disappears. Perform this measurement at 10 different locations and calculate the simple average of these values, set the unit to seconds, and round off the first decimal place.

(9) Water absorption and quick-drying properties For the multi-layer nonwoven fabrics after the water distribution ratio in (7) was measured, healthy adults (15 males and 15 females, a total of 30 subjects) touched the "absorption surface" side with their hands and evaluated the dryness of the surface in the following three stages. The average score of the evaluation results was calculated for each nonwoven fabric and used as the skin touch of the multi-layer nonwoven fabric. 5: The surface is dry to the touch, and no moisture is felt 3: Although there is no moisture on the surface, it is wet 1: There is moisture on the surface and it is wet [Example 1] (Non-woven fiber web layer (A)) Polypropylene (PP, melt viscosity 30Pa‧s) is melted by an extruder and spun from a rectangular nozzle at a single-hole discharge rate of 0.3g/min. After the spun filaments are cooled and solidified, they are pulled and stretched in a rectangular ejector by setting the pressure in the ejector to 0.10MPa of compressed gas, and captured on a moving net to obtain a non-woven fiber web layer (A) by a spinning and bonding method. The fibers constituting the obtained nonwoven fiber web layer (A) had an average single fiber diameter of 10.6 μm and a basis weight of 35.0 g/m ² .

(Nonwoven fiber web layer (B)) Polypropylene (PP) which is the same raw material as that used for the nonwoven fiber web layer (A) is melted by an extruder and spun out from a rectangular nozzle at a single-hole discharge rate of 0.85 g/min. The spun filaments are cooled and solidified, and then pulled and stretched in a rectangular ejector by a compressed gas with a pressure of 0.08 MPa in the ejector, and captured on the nonwoven fiber web layer (A) on the moving net to obtain a nonwoven fiber web layer (B) by a spunbonding method. The fibers constituting the obtained nonwoven fiber web layer (B) have an average single fiber diameter of 20.4 μm. In addition, the basis weight was set to 30.0 g/m ² .

By capturing the non-woven fiber web layer (B) on the non-woven fiber web layer (A) and laminating them on a production line, a laminated fiber web having a two-layer structure of the non-woven fiber web layer (A)/non-woven fiber web layer (B) is obtained.

(Laminated nonwoven fabric) The obtained laminated fiber web was heat-bonded at a linear pressure of 300 N/cm and a heat-bonding temperature of 125°C using an embossing roller having a pair of heating mechanisms, with a metal pressure roller having perfectly circular protrusions arranged in a chimera pattern at the same interval in both the MD and CD directions and a metal flat roller as a lower roller, and then subjected to hydrophilic treatment to obtain a laminated nonwoven fabric having a basis weight of 65.0 g/ ^m2 .

The thickness, inter-fiber space size, water distribution ratio, water absorption speed, and water absorption and quick-drying properties of the obtained laminated nonwoven fabric were evaluated. The thickness of the nonwoven fabric layer (A) was 300 μm, and the inter-fiber space size was 54 μm. In addition, the thickness of the nonwoven fabric layer (B) was 420 μm, and the inter-fiber space size was 181 μm. The results are shown in Table 1.

[Example 2] Except that the single hole discharge amount was set to 0.80 g/min in the step of preparing the nonwoven fiber mesh layer (A), and the single hole discharge amount was set to 1.20 g/min in the step of preparing the nonwoven fiber mesh layer (B), the rest was carried out in the same manner as in Example 1 to obtain a laminated nonwoven fabric. The evaluation results of the obtained laminated nonwoven fabric are shown in Table 1.

[Example 3] Except that the single hole discharge rate was set to 0.35 g/min in the step of preparing the nonwoven fiber mesh layer (B), the rest was carried out in the same manner as in Example 1 to obtain a laminated nonwoven fabric. The evaluation results of the obtained laminated nonwoven fabric are shown in Table 1.

[Example 4] A laminated nonwoven fabric was obtained in the same manner as in Example 1 except that the basis weight of the nonwoven web layer (A) was 15.0 g/m ² and the basis weight of the nonwoven web layer (B) was 13.0 g/m ^2. The evaluation results of the obtained laminated nonwoven fabric are shown in Table 1.

[Example 5] A laminated nonwoven fabric was obtained in the same manner as in Example 1 except that the basis weight of the nonwoven fiber web layer (A) was changed to 10.0 g/m ^2. The evaluation results of the obtained laminated nonwoven fabric are shown in Table 1.

[Example 6] (Nonwoven fiber mesh layer (A)) The same process as in Example 1 was performed to obtain a nonwoven fiber mesh layer (A).

(Nonwoven fiber mesh layer (B)) Except for directly capturing the pulled and stretched filaments on the moving net, the rest is carried out in the same manner as in Example 1 to obtain a nonwoven fiber mesh layer (B).

After the nonwoven fiber mesh layer (A) and the nonwoven fiber mesh layer (B) are obtained respectively, they are laminated on a lamination production line to obtain a laminated fiber mesh having a two-layer structure of the nonwoven fiber mesh layer (A)/nonwoven fiber mesh layer (B).

(Laminated nonwoven fabric) The obtained laminated fiber web was subjected to hydrophilic treatment by thermal bonding in the same manner as in Example 1 to obtain a laminated nonwoven fabric. The evaluation results of the obtained laminated nonwoven fabric are shown in Table 1.

[Example 7] The polymer used in the non-woven fabric layer (A) and the non-woven fabric layer (B) is set to polyethylene glycol copolymerized polyethylene terephthalate (copolymerized PET, the copolymerization ratio of polyethylene glycol is 8% by mass of the polymer).

(Nonwoven fiber web layer (A)) As the fiber raw material polymer, a copolymerized polyethylene terephthalate (copolymerized PET) in which polyethylene glycol was copolymerized to 8 mass % of the polymer was used. The copolymerized PET was used, and the nonwoven fiber web layer (A) was obtained in the same manner as in Example 1 except that the running speed of the web was changed. The fibers constituting the obtained spunbond nonwoven fabric layer (A) had an average single fiber diameter of 8.5 μm. The basis weight was set to 30.0 g/m ² .

(Nonwoven fiber web layer (B)) The same process as in Example 1 was carried out except that the same copolymerized PET as the raw material used in the nonwoven fiber web layer (A) was used to obtain a nonwoven fiber web layer (B). The properties of the fibers constituting the obtained spunbond nonwoven fabric layer (B) were that the average single fiber diameter was 17.5 μm. The basis weight was set to 37.0 g/m ² .

(Laminated nonwoven fabric) A laminated nonwoven fabric was obtained by the same method as in Example 1 except that the thermal bonding temperature was set to 200°C. The thickness of the nonwoven fabric layer (A) was 270 μm, and the size of the inter-fiber gap was 73 μm. The thickness of the nonwoven fabric layer (B) was 350 μm, and the size of the inter-fiber gap was 158 μm. The evaluation results of the obtained laminated nonwoven fabric are shown in Table 1.

[Comparative Example 1] Except that the single hole discharge rate is set to 1.20 g/min in the step of preparing the nonwoven fiber mesh layer (A), the pressure in the ejector is set to 0.08 MPa, and the single hole discharge rate is set to 1.20 g/min in the step of preparing the nonwoven fiber mesh layer (B), the rest is carried out in the same manner as in Example 1 to obtain a laminated nonwoven fabric. The fibers constituting the obtained nonwoven fiber mesh layer (A) have an average single fiber diameter of 22.0 μm. In addition, the thickness of the nonwoven fabric layer (A) is 430 μm, and the inter-fiber gap size is 245 μm. The evaluation results of the obtained laminated nonwoven fabric are shown in Table 1.

[Table 1] Embodiment 1 Embodiment 2 Embodiment 3 Embodiment 4 Embodiment 5 Embodiment 6 Embodiment 7 Comparison Example 1 Non-woven fabric layer (A) Thermoplastic resin — PP PP PP PP PP PP Copolymer PET PP Average single fiber diameter μm 10.6 19.5 10.6 10.6 10.6 10.6 8.5 22.0 Basis Weight g/ ^m2 35.0 28.0 35.0 15.0 10.0 35.0 30.0 25.0 thickness μm 300 440 300 110 90 350 270 430 Fiber space size μm 54 197 54 44 57 64 73 245 Non-woven fabric layer (B) Thermoplastic resin — PP PP PP PP PP PP Copolymer PET PP Average single fiber diameter μm 20.4 25.0 12.6 20.4 20.4 20.4 17.5 25.0 Basis Weight g/ ^m2 30.0 30.0 35.0 13.0 30.0 30.0 37.0 30.0 thickness μm 420 500 270 95 420 450 350 500 Fiber space size μm 181 270 56 85 181 196 158 270 Laminated nonwoven fabric Layered structure — A/B A/B A/B A/B A/B A/B A/B A/B Cumulative method — Production line Production line Production line Production line Production line Outside the production line Production line Production line Bonding method — Embossing Embossing Embossing Embossing Embossing Embossing Embossing Embossing Ratio of inter-fiber void size (Rb/Ra) — 3.4 1.4 1.0 1.9 3.2 3.0 2.2 1.1 Water distribution ratio of absorption surface (side B) % 5 28 39 41 20 twenty one 10 45 Water distribution ratio on the side opposite to the absorption side (side A) % 70 58 51 50 45 51 66 48 Water absorption speed s 1 2 5 2 2 3 3 2 Water absorption and quick drying point 4.6 3.8 3.4 3.3 4.1 4.1 4.5 2.5

As shown in Table 1, it can be seen that Examples 1 to 7 are superior in water absorption and quick drying. In particular, Examples 1 and 6 take both water absorption speed and water absorption and quick drying into consideration at a high level. On the other hand, the result of Comparative Example 1 is that the water absorption and quick drying are low.

Claims (10)

A laminated nonwoven fabric is formed by laminating nonwoven fabric layers composed of thermoplastic resin fibers, wherein in the nonwoven fabric layer (A) having the smallest average single fiber diameter, the inter-fiber space size Ra (μm) calculated according to the following formula (1) is less than 200 μm; Ra=(100×Ta×da)/(Wa×Da)-Da…Formula (1) wherein Ta: thickness of the nonwoven fabric layer (A) (μm) da: fiber density of the thermoplastic resin fibers constituting the nonwoven fabric layer (A) (dtex) Wa: basis weight of the nonwoven fabric layer (A) (g/ ^m2 )Da: Average single fiber diameter of the thermoplastic resin fiber constituting the nonwoven fabric layer (A) (μm). The laminated nonwoven fabric of claim 1, wherein, in at least one layer of the nonwoven fabric layer (B) laminated in contact with the nonwoven fabric layer (A), the ratio Rb/Ra of the inter-fiber gap size Rb (μm) calculated according to the following formula (2) to the above Ra is 1.1 or more; Rb=(100×Tb×db)/(Wb×Db)-Db…Formula (2) wherein, Tb: thickness of the nonwoven fabric layer (B) (μm) db: fiber density of the thermoplastic resin fiber constituting the nonwoven fabric layer (B) (dtex) Wb: basis weight of the nonwoven fabric layer (B) (g/ ^m2 )Db: Average single fiber diameter of the thermoplastic resin fiber constituting the nonwoven fabric layer (B) (μm). A laminated nonwoven fabric as claimed in claim 1 or 2, wherein, when physiological saline is absorbed on both sides of the laminated nonwoven fabric according to the following steps, the water distribution ratio defined by the following formula (3) on at least one of the four surfaces, namely, the absorption surface on which the physiological saline is absorbed and the surface on the opposite side thereof, is 40% or less; step 1: cutting a 5 cm x 5 cm sample from the laminated nonwoven fabric; step 2: preparing two pieces for each measurement according to JIS The two types of filter paper of P3801 are cut into 5cm×5cm pieces, and the mass is measured respectively; Step 3: 0.250±0.005mL of physiological saline is dripped on the polypropylene film, and the mass of the physiological saline dripped is measured in advance; Step 4: A laminated non-woven fabric is placed on the dripped physiological saline with the absorption surface of the physiological saline facing downward, and kept for 1 minute; Step 5: After the above step 4, the laminated non-woven fabric is removed from the above polypropylene film, and placed on the first piece of the above filter paper with the absorption surface facing upward, and then the second piece of the above filter paper is quickly placed on it; Step 6: A pressure of 5g/cm ² , place a 125g weight and keep it for 1 minute; step 7: after keeping in the above step 6, remove the weight, measure the mass of each filter paper, and calculate the mass increase of each filter paper; step 8: calculate the water distribution ratio of each surface of the above laminated non-woven fabric by the following formula; water distribution ratio (%) = 100 × W1/W0, wherein W0: the mass of the physiological saline solution dripped in the above step 3 (g); W1: the mass increase of the filter paper abutting on its surface in the above step 7 (g). For the laminated nonwoven fabric of claim 3, the water distribution ratio of the opposite side of the surface having a water distribution ratio of less than 40% is greater than 50%. For a laminated nonwoven fabric as claimed in claim 1 or 2, the water absorption rate measured by the dripping method of JIS L1907:2010 on at least one surface is less than 20 seconds. A sanitary material, at least a part of which is composed of a laminated nonwoven fabric as claimed in any one of claims 1 to 5. As in claim 6, the sanitary material is a diaper. As in claim 7, the sanitary material, wherein the surface sheet is composed of the above-mentioned laminated nonwoven fabric. As in claim 7, the sanitary material, wherein at least a portion of the waistline is formed by the above-mentioned laminated nonwoven fabric. As in claim 7, the sanitary material is a mask, and the inner surface layer of the mask is composed of the laminated non-woven fabric.