JP6587509B2 - Laminated nonwoven fabric - Google Patents

Description

  The present invention relates to a laminated nonwoven fabric.

In absorbent articles such as sanitary napkins, panty liners, and diapers, a nonwoven fabric having a concavo-convex structure and a two-layer structure are used depending on the function.
For example, the nonwoven fabric described in Patent Document 1 has a two-layer structure composed of first and second sheets, and both sheets have an uneven structure. The 2nd protrusion part which protruded in the 2nd surface side of the 1st sheet | seat and the 3rd protrusion part which protruded in the 1st surface side of the 2nd sheet | seat are joined. Moreover, it has fiber orientation along the direction which connects the top part of a 1st protrusion part, and its opening part.

  Moreover, the nonwoven fabric described in Patent Document 2 has a two-layer structure of an upper layer sheet and a lower layer sheet. Both sheets are partly joined to form a number of joints. The upper sheet protrudes toward the skin contact surface in a region surrounded by a plurality of joints, and has a large number of convex portions.

JP 2013-194333 A JP 2009-118920 A

The non-woven fabric of Patent Document 1 is excellent in shape retention, and is supposed to give a three-dimensional cushioning property supported by points on both sides corresponding to the wearer's three-dimensional movement. Thus, since it is excellent in the followability with respect to a three-dimensional motion, since the shape is easily distorted, there is room for improvement in the shape retention of the nonwoven fabric.
Moreover, since the uneven | corrugated shape of the upper layer sheet | seat was made by the meshing | engagement of the gear-shaped member, the nonwoven fabric of patent document 2 was in the state where the rise of the side wall was steep. Further, the shape of the side wall of the convex portion is substantially rectangular in plan view. Therefore, there is room for improving the cushioning property in order to further improve the cushioning property.

  An object of the present invention is to provide a laminated nonwoven fabric that is excellent in shape retention under pressure and that provides a good cushion feeling.

The laminated nonwoven fabric of the present invention protrudes to the first surface side of the nonwoven fabric in plan view, and has a first protruding portion having an internal space on the second surface side opposite to the first surface side. And a second projecting portion projecting to the second surface side and having an internal space on the first surface side, wherein the first and second projecting portions are different from each other in plan view of the nonwoven fabric. A plurality of first non-woven sheets arranged alternately in each direction;
A third projecting portion continuously projecting in one direction on the first surface side and having an internal space continuous on the second surface side; and continuous in a direction along the one direction on the second surface side. And a fourth projecting portion having a continuous inner space on the first surface side, and the third and fourth projecting portions intersect the one direction in plan view of the nonwoven fabric. A plurality of second nonwoven sheets arranged alternately in the direction,
The second nonwoven fabric sheet is arranged on the second surface side of the first nonwoven fabric sheet, and the top region of the fourth projecting portion corresponding to the top region of the second projecting portion among the plurality of fourth projecting portions. A laminated nonwoven fabric in which the back surface side of the first protrusion and the top region of the second protrusion are joined.

  According to the laminated nonwoven fabric of this invention, it is excellent in the shape retainability under pressure, can obtain a good cushion feeling, and can reduce the liquid return amount.

1 is a partial cross-sectional perspective view schematically showing a preferred embodiment of a laminated nonwoven fabric according to the present invention. It is the fragmentary sectional view which showed the xz cross section which passes each top part of the 1st to 4th protrusion part shown in FIG. It is the fragmentary sectional view which showed the yz cross section which passes along the junction part of the top part of the 2nd protrusion part shown in FIG. 1, and the top back surface of the 4th protrusion part. It is the perspective view which showed one preferable embodiment of the 2nd nonwoven fabric sheet. It is the fragmentary sectional view which showed the xz cross section of the 2nd nonwoven fabric sheet shown in FIG. It is the fragmentary sectional view which showed the xz cross section of the 2 nonwoven fabric sheet shown in FIG. It is the top view which showed typically arrangement | positioning of the small diameter part and large diameter part between fusion parts about the constituent fiber of a 2nd nonwoven fabric sheet. BRIEF DESCRIPTION OF THE DRAWINGS It is drawing which showed preferable embodiment of the manufacturing method of a laminated nonwoven fabric, (a) is the schematic diagram which showed the flow state of the hot air at the time of shaping, (b) showed the laminated nonwoven fabric after shaping x It is sectional drawing of a -z cross section. It is the perspective view which showed the state of the extending | stretching process using a pair of uneven | corrugated roll used in the extending | stretching process of a 2nd nonwoven fabric sheet, and the uneven | corrugated roll. It is the fragmentary sectional view which showed the circumferential direction cross section of the uneven | corrugated roll shown in FIG. It is the perspective view which showed the state of the extending | stretching process using another pair of uneven | corrugated roll used in the extending | stretching process of a 2nd nonwoven fabric sheet, and the uneven | corrugated roll. 1 is a partially cutaway perspective view schematically showing a diaper as a preferred embodiment of an absorbent article using a surface sheet according to the present invention. FIG. 3 is a drawing-substituting photograph taken from the side of the laminated nonwoven fabric produced in Example 1 and corresponds to the xz cross section described in FIG. 2.

A preferred embodiment (first embodiment) of the laminated nonwoven fabric according to the present invention will be described below with reference to FIG.
The laminated nonwoven fabric 10 of the present invention is preferably applied to a top sheet of an absorbent article such as a sanitary napkin or a diaper. At that time, it is preferable to use the first surface side Z1 facing the wearer's skin surface and the second surface side Z2 arranged on the absorber (not shown) side inside the article. Hereinafter, it demonstrates considering the embodiment which uses 1st surface side Z1 of the laminated nonwoven fabric 10 shown in drawing toward a wearer's skin surface. The present invention is not construed as being limited thereby.

As shown in FIGS. 1 and 2, the laminated nonwoven fabric 10 is composed of two layers, a first nonwoven fabric sheet 11 and a second nonwoven fabric sheet 21. And each sheet | seat makes the continuous uneven | corrugated curved surface, and has comprised the seamless sheet surface.
The 1st nonwoven fabric sheet 11 protrudes in the 1st surface side Z1 of the side seen by plane, The 1st protrusion part which has the internal space 13 opened to the 2nd surface side Z2 on the opposite side to the 1st surface side Z1. 12 is provided. Furthermore, the 2nd protrusion part 14 which protrudes in the 2nd surface side Z2 and has the internal space 15 opened to the 1st surface side Z1 is provided. And the 1st, 2nd protrusion parts 12 and 14 are distribute | arranged in the state where multiple were alternately continued in each of the different direction which crosses planar view of the laminated nonwoven fabric 10. FIG. The different directions are, for example, an x direction (x axis direction) and a y direction (y axis direction) different from the x direction. The intersection angle between the x-axis and the y-axis is preferably 30 ° or more and 90 ° or less, and is 90 ° in this embodiment. Also, the first surface side Z1 is the upper side in the z-axis direction, and the second surface side Z2 is the lower side in the z-axis direction.

  The 2nd nonwoven fabric sheet 21 is provided with the 3rd protrusion part 22 which protrudes continuously in one direction of the 1st surface side Z1, and has the internal space 23 continued to the 2nd surface side Z2. Moreover, the 4th protrusion part 24 which has the internal space 25 which protrudes continuously in the direction along the said one direction of the 2nd surface side Z2 and has opened continuously to the 1st surface side Z1 is provided. Yes. That is, when viewed from the first surface side Z1, the third protrusion 22 is a hook-shaped protrusion. Further, the internal space 25 of the fourth projecting portion 24 is a groove-shaped concave portion arranged in parallel adjacent to the bowl-shaped convex portion. Therefore, the 3rd, 4th protrusion parts 22 and 24 are distribute | arranged by the state which several alternately continued in the direction which cross | intersects the said one direction of the laminated nonwoven fabric 10 in the planar view, for example, the orthogonal direction. The one direction is, for example, the x direction or the y direction when the x direction and the y direction are orthogonal to each other. In the illustrated example, the one direction is the y direction.

Furthermore, the second nonwoven fabric sheet 21 is arranged on the second surface side Z <b> 2 of the first nonwoven fabric sheet 11. And among the 4th protrusion part 24, the back surface side of the top area | region 24T of the 4th protrusion part 24 corresponding to the top area | region 14T of the 2nd protrusion part 14 and the top area | region 14T of the 2nd protrusion part 14 are joined. . The back side of the top region 24T is the bottom region 25B of the internal space 25.
In the joining of the top region 14T and the back surface side of the top region 24T, it is preferable that the peripheral region of the joint portion between the vertex of the top region 14T and the back surface side of the vertex of the top region 24T is also joined. That is, it is preferable that the apex side of the wall portion 16 in the second protrusion 14 and the bottom side of the wall portion 26 in the internal space 25 of the fourth protrusion 24 are joined.

  Furthermore, the internal space 25 of the 4th protrusion part 24 which is not joined to the top area | region 14T among the 4th protrusion parts 24 is distribute | arranged corresponding to the position of the internal space 13 of the 1st protrusion part 12. FIG. The internal space 13 is continuously connected in an oblique direction with respect to an intermediate direction between the x direction and the y direction, that is, the x direction and the y direction, and constitutes one space. Note that the angle of the oblique direction with respect to the x direction and the y direction varies depending on the pitches of the first protrusion 12 and the second protrusion 14 in the MD direction and the CD direction. MD is also referred to as the machine direction, and is the direction in which the fiber web is conveyed during the production of the nonwoven fabric, and is an abbreviation for “Machine Direction”. The CD is a direction orthogonal to the MD and is an abbreviation of “Cross Direction”.

  Moreover, as shown in FIG. 3, the 4th protrusion part 24 of the 2nd nonwoven fabric sheet 21 has a gentle uneven | corrugated shape in the said one direction (y direction). That is, the fourth protrusion 24 has a small protrusion 24 a that protrudes in the first surface side Z <b> 1 direction corresponding to the first protrusion 12. Moreover, it has the small convex part 24b which protrudes in the 2nd surface side Z2 direction corresponding to the 2nd protrusion part 14. As shown in FIG.

As for the said laminated nonwoven fabric 10, the top area | region 14T and the back surface side of the top area | region 24T are joined. Thereby, the 2nd protrusion part 14 equivalent to the base (rise part) of the 1st protrusion part 12 is fixed by the 2nd nonwoven fabric sheet 21. FIG. For this reason, since the base part of the 1st protrusion part 12 is supported firmly, even if it is in the state which received the pressurization, the shape of the 1st protrusion part 12 becomes easy to be hold | maintained. Therefore, it is excellent in shape retention under pressure. Since the 1st protrusion part 12 has the dome-shaped internal space 13, a favorable cushion feeling is obtained. Further, since the joining portion becomes higher in density by joining the top region 14T and the back surface side of the top region 24T, the drawability of the liquid is improved. As a result, the liquid drawn into the joining region is easily absorbed by the absorber (not shown).
Furthermore, the internal space 13 is continuously connected in an oblique direction. From this, when pressure is applied to the laminated nonwoven fabric 10 from the outside in a state in which the internal space 13 of one first protrusion 12 is filled with the liquid, the liquid flows into the adjacent internal space 13. Therefore, liquid return can be suppressed. Thereby, a sufficient amount of liquid retained by the internal space 13 can be secured. Moreover, the internal space 13 makes it easier for the liquid to reach the absorber (not shown) directly, and the liquid absorption speed is increased.

Further, the laminated nonwoven fabric 10 will be described in detail.
The top region 12T of the first projecting portion 12 and the top region 14T of the second projecting portion 14 each have a rounded truncated cone shape or a hemispherical shape. In the present embodiment, the first projecting portion 12 and the second projecting portion 14 are not limited to the shape described above, and any projecting form may be used. For example, it is practical to have various cone shapes. This pyramid shape is meant to include a wide range of cones, truncated cones, pyramids, truncated pyramids, oblique cones, and the like.
Moreover, in the top area | region (henceforth 1st protrusion part top part) 12T of the 1st protrusion part 12, it has the truncated cone shape or hemispherical internal space 13 with the roundness similar to the external shape. Similarly, in the top region (hereinafter also referred to as the second projecting portion top portion) 14T of the second projecting portion 14, a round truncated cone-like or hemispherical internal space 15 similar to the outer shape thereof is provided. .

A wall 16 (16a) is provided between the top region 12T of the first protrusion 12 and the opening 12H opened on the second surface side Z2 of the first protrusion 12. The opening 12H refers to the peripheral edge on the second surface side Z2 of the wall portion 16a of the first projecting portion 12 when viewed from the second surface side Z2. The wall portion 16 a is a portion that forms an annular structure in the first projecting portion 12. The wall portion 16 (16b) is provided between the top region 14T of the second projecting portion 14 and the opening portion 14H opened on the first surface side Z1 of the second projecting portion 14. The opening 14H refers to the periphery on the first surface side Z1 of the wall portion 16b of the second protrusion 14 as viewed from the first surface side Z1. The wall portion 16b is a portion that forms an annular structure in the second protrusion 14. Therefore, the wall portions 16a and 16b have a common annular structure in the first protrusion 12 and an annular structure in the second protrusion 14 in part.
The “annular” is not particularly limited as long as it has an endless series of shapes in plan view, and may be any shape such as a circle, an ellipse, a rectangle, or a polygon in plan view. In order to suitably maintain the continuous state of the sheet, a circle or an ellipse is preferable in plan view. Speaking of “circular” as a three-dimensional shape, cylindrical, oblique cylinder, elliptical cylinder, truncated cone, truncated oblique cone, truncated elliptical cone, truncated quadrangular pyramid, truncated oblique pyramid And any ring structure. In order to realize a continuous sheet state, a cylindrical shape, an elliptic cylinder shape, a truncated cone shape, and a truncated elliptical cone shape are preferable.

  The thickness P1 of the 1st protrusion part 12, the thickness P3 of the wall part 16, and the thickness P2 of the 2nd protrusion part 14 of the 1st nonwoven fabric sheet 11 shown in FIG. 2 are the site | parts divided into 3 parts typically Is defined as However, when the kurtosis or curvature of the tops of the first protrusion 12 and the second protrusion 14 are different, the following is specified. That is, a relatively narrow portion that is linear in the cross section may be used as the wall portion 16, and the curved and rounded regions may be used as the first projecting portion 12 and the second projecting portion 14, respectively. In the latter definition, for example, the first protrusion 12 has a gentler curved surface with a smaller curvature (a larger radius of curvature) than the second protrusion 14. In this case, the 2nd protrusion part 14 is divided long in the sheet | seat thickness direction rather than the 1st protrusion part 12, and becomes a form with the bias | inclination in the thickness direction as a whole.

  The 1st nonwoven fabric sheet 11 which has the 1st, 2nd protrusion parts 12 and 14 arrange | positioned as mentioned above does not have a bending part, and is comprised by the curved surface which the whole continued. Thus, it is preferable that the 1st nonwoven fabric sheet 11 has a structure continuous in the surface direction. This “continuous” means that there are no intermittent portions or small holes. However, fine holes such as gaps between fibers are not included in the small holes. The small hole is defined as, for example, a hole having a diameter equivalent to a circle of 1 mm or more.

Next, the fiber density of the first nonwoven fabric sheet 11 will be described.
The first nonwoven fabric sheet 11 has the lowest fiber density of the first protrusions 12 and the highest fiber density of the second protrusions 14. It is more preferable that there is a density gradient in which the fiber density increases from the first protrusion 12 toward the second protrusion 14. The gradient of the fiber density widely includes various modes in which the fiber density increases from the first protrusion 12 toward the second protrusion 14. For example, the aspect in which the gradient of the fiber density is gradually increased or may be increased stepwise. The fiber density is a fiber mass per unit area of the nonwoven fabric, and is measured by a measurement method described later. High fiber density means that the amount of fibers present per unit area of the nonwoven fabric is large, and means that the distance between fibers is short. Low fiber density means that the amount of fibers present per unit area of the nonwoven fabric is small and the distance between fibers is long. Therefore, the portion with high fiber density has higher capillary force than the portion with low fiber density.

  Thereby, when liquids, such as excrement, are supplied from the 1st surface side Z1 of the lamination nonwoven fabric 10, liquid resistance is reduced in the 1st protrusion part 12, and the liquid is guide | induced to the internal space 13 rapidly. At the same time, the liquid moves through the wall portion 16 to the internal space 15 by the capillary force due to the fiber density difference. For this reason, when this laminated nonwoven fabric is applied to the top sheet of the absorbent article, the liquid is quickly transferred from the skin surface side and quickly delivered to the absorber (not shown). As a result, liquids such as excreta are less likely to adhere to the skin, and it is possible to prevent the wearer from causing rough skin such as redness and itchiness or dermatitis such as eczema and rash.

The fiber density is a fiber density near the center of the layer thickness of the top regions 12T and 14T at which the first protrusion 12 and the second protrusion 14 are most protruded. A wall portion (hereinafter also referred to as an annular wall portion) 16 is a fiber density near the center of the layer thickness in the vicinity of the center in the sheet thickness direction. In the nonwoven fabric of this embodiment, the fiber density in the 1st protrusion part 12 is smaller than the fiber density in the 2nd protrusion part 14. FIG. Thereby, in the 1st protrusion part 12, it does not give the feeling which smashes into a skin moderately with respect to a press, and can implement | achieve favorable skin contact. On the other hand, the 2nd protrusion part 14 is hard to be crushed, is excellent in preserving after excrement is collected, and is excellent in a good cushioning property and an anti-diffusion property of the collected product without collapsing.
Evaluation is made by measuring the number of fibers per 1 mm ² in each of the above-mentioned parts. For example, the fiber density of the first protrusions 12 is preferably 30 / mm ² or more, and more preferably 50 / mm ² or more, from the viewpoint of improving the texture of the nonwoven fabric surface. Then, preferably at 130 present / mm ² or less, and more preferably, 120 / mm ² or less. More specifically, the number is 30 / mm ² or more and 130 / mm ² or less, preferably 50 / mm ² or more and 120 / mm ² or less. On the other hand, the fiber density of the second protrusions 14 is preferably 250 / mm ² or more, more preferably 270 / mm ² or more, from the viewpoint of having a reliable cushioning property without losing shape. preferable. Then, preferably at 500 / mm ² or less, more preferably 480 / mm ² or less. More specifically, 250 / mm ² or more and 500 / mm ² or less is preferable, and 270 / mm ² or more and 480 / mm ² or less is more preferable.
The difference between the fiber density of the first protrusions 12 and the fiber density of the second protrusions 14 is preferably 150 / mm ² or more, and more preferably 300 / mm ² or more. This difference is preferably as large as possible, but the upper limit is about 700 / mm ² .
Furthermore, the fiber density of the annular wall portion 16 is preferably 150 fibers / mm ² or more. Then, preferably at 450 present / mm ² or less, more preferably 350 present / mm ² or less. More specifically, 150 / mm ² or more and 450 / mm ² or less is preferable, and 150 / mm ² or more and 350 / mm ² or less is more preferable.

The average fiber density of the first nonwoven fabric sheet 11 is preferably lower than the average fiber density of the second nonwoven fabric sheet 21.
As a result, the first nonwoven fabric sheet 11 is more liquid permeable than the second nonwoven fabric sheet 21, and the liquid is drawn into the internal space 13 of the first protrusion 12, so that the liquid residue is reduced. The drawn liquid moves to the second nonwoven fabric sheet 21 having excellent liquid absorbability, is drawn into the internal space 23 of the third protrusion 22 and is absorbed by the absorber (not shown). For this reason, the liquid return in the 2nd nonwoven fabric sheet 21 is reduced.

The fiber density is measured by the following method.
Using a scanning electron microscope, the cut surface of the nonwoven fabric is adjusted to a measurement magnification of 150 to 500 times that enables enlarged observation of 30 to 60 fiber cross sections. And the cross-section number of a fiber is measured and the cross-section number of the fiber currently cut | disconnected by the cut surface per fixed area is counted. The center of observation is near the center of the layer thickness of the top region 12T of the first protrusion 12, and the wall 16 is near the center of the layer thickness near the center in the sheet thickness direction. The second protrusion 14 is near the center of the layer thickness of the top region 14T. Next, it is converted into the number of cross-sections of the fiber per 1 mm ² and this is defined as the fiber density (lines / mm ² ). The measurement is performed at three locations, and the average is the fiber density of the sample. JCM-5100 (trade name) manufactured by JEOL Ltd. can be used for the scanning electron microscope.

The average fiber density of the 1st nonwoven fabric sheet 11 is taken as the average value of the fiber density of the top area | region 12T of the 1st protrusion part, the cyclic | annular wall part 16, and the top area | region 14T of a 2nd protrusion part. Similarly, the average fiber density of the second nonwoven fabric sheet 21 is also set to the average value of the fiber densities of the third protrusions 22, the fourth protrusions 24, and the walls 26 (see FIG. 2).
The average fiber density of the first nonwoven fabric sheet 11 is 140 / mm ² or more, and preferably 160 / mm ² or more. And it is 320 pieces / mm < ² > or less, and 300 pieces / mm < ² > or less is preferable. More specifically, it is 140 / mm ² or more and 320 / mm ² or less, and preferably 160 / mm ² or more and 300 / mm ² or less.
The average fiber density of the 2nd nonwoven fabric sheet 21 is 490 / mm < ² > or more, and 560 / mm < ² > or more is preferable. And it is 1120 piece / mm < ² > or less, and 1050 piece / mm < ² > or less is preferable. More specifically, it is 490 / mm ² or more and 1120 / mm ² or less, and preferably 560 / mm ² or more and 1050 / mm ² or less.

Next, the thickness of the laminated nonwoven fabric 10 will be described below.
A load is applied to the laminated nonwoven fabric 10 so that a pressure of 0.05 kPa is applied over the entire surface of the sheet. The thickness t at this time is preferably 2 mm or more, more preferably 3.5 mm or more, and further preferably 5 mm or more. And preferably it is 14 mm or less, More preferably, it is 9 mm or less, More preferably, it is 7.5 mm or less. More specifically, it is preferably 2 mm or more and 14 mm or less, more preferably 3.5 mm or more and 9 mm or less, and further preferably 5 mm or more and 7.5 mm or less. If the thickness is too thick, when used as a surface material of an absorbent article, it becomes uncomfortable at the time of wearing. On the other hand, if the thickness is too thin, sufficient cushioning properties cannot be obtained and the liquid return amount increases. Note that the thickness T described above refers to the average value of the height from the top of the first protrusion 12 to the top of the fourth protrusion 24 as viewed in the z-axis direction.
The thickness t1 of the first nonwoven fabric sheet 11 is preferably 1 mm or more, more preferably 2 mm or more, and further preferably 3 mm or more. And preferably it is 10 mm or less, More preferably, it is 6 mm or less, More preferably, it is 5 mm or less. More specifically, it is preferably 1 mm or more and 10 mm or less, more preferably 2 mm or more and 6 mm or less, and further preferably 3 mm or more and 5 mm or less.
Furthermore, the thickness t2 of the second nonwoven fabric sheet 21 is preferably 1 mm or more, more preferably 1.5 mm or more, and further preferably 2 mm or more. And preferably it is 4 mm or less, More preferably, it is 3 mm or less, More preferably, it is 2.5 mm or less. More specifically, it is preferably 1 mm or more and 4 mm or less, more preferably 1.5 mm or more and 3 mm or less, and further preferably 2 mm or more and 2.5 mm or less.

Next, the orientation of the fibers constituting the laminated nonwoven fabric 10 will be described.
The fibers constituting the wall 16 (16a) of the first protrusion 12 of the laminated nonwoven fabric 10 have fiber orientation in the direction connecting the first protrusion top 12T and the edge of the opening 12H over the entire circumference of the wall 16a. Have. In other words, the fibers constituting the wall portion 16a are oriented so as to converge toward the first projecting portion top portion 12T, and have fiber orientation in the standing direction. Moreover, the fiber which comprises the wall part 16 (16b) of the said 2nd protrusion part 14 has fiber orientation in the direction which ties the edge part of the 2nd protrusion part top part 14T and the opening part 14H over the perimeter of the wall part 16b. Therefore, the fiber orientation of the first protrusion 12 and the second protrusion 14 is the same at the wall 16.
As a result, a firm stiffness is produced in the wall portion 16 connecting the first projecting portion 12 and the second projecting portion 14, and an appropriate cushioning property can be realized without the fibers being crushed in the thickness direction.

The fiber orientation is a concept consisting of the orientation angle and orientation strength of the fiber.
The fiber orientation angle is a concept that indicates in which direction a plurality of fibers having various directions are oriented as a whole, and the shape of the fiber aggregate is quantified. The orientation strength of the fiber is a concept indicating the amount of fibers exhibiting an orientation angle. The orientation strength is less than 1.05 and is hardly oriented, and it can be said that the orientation strength is 1.05 or more. However, in this embodiment, the fiber orientation changes depending on the part. That is, it has various states such as a state in which the orientation strength is weak and a state in which the orientation is high due to reorientation while changing from a part having a certain orientation angle to a part having a different orientation angle. Therefore, it is preferable that the orientation angle of the fiber is changed between a portion showing a strong orientation angle and a portion showing a strong orientation angle in another direction even if the orientation strength of the fiber is weak. It is more preferable that the orientation strength is high.
An example of the orientation angle and orientation strength is shown in this embodiment. The orientation angle with respect to the curved surface structure of the wall 16a of the first protrusion 12 is preferably 50 ° or more, and more preferably 60 ° or more. And 130 degrees or less are preferable and 120 degrees or less are more preferable. More specifically, it is preferably 50 ° or more and 130 ° or less, and more preferably 60 ° or more and 120 ° or less.
The orientation strength is preferably 1.05 or more, and more preferably 1.10 or more. And the wall part 16b of the 2nd protrusion part 14 is also the same.
By setting the orientation strength and the orientation angle as described above, the load in the thickness direction is firmly received, and the first protrusion 12 and the second protrusion 14 are not crushed even under a high load. This can also reduce the liquid return amount.

  The laminated nonwoven fabric 10 is used as a surface sheet of an absorbent article. In this case, the fiber orientation of each wall portion 16 of the first nonwoven fabric sheet 11 has sufficient compression resistance even under high pressure, and prevents the first protrusion 12 and the second protrusion 14 from being crushed. Thus, a sufficient liquid capture space can be secured. As a result, the effect of reducing the skin contact area, the effect of obtaining high air permeability, a large amount of liquid, solid content, highly viscous liquid, etc. are sufficiently captured and the effect of suppressing leakage is sufficiently exhibited.

Next, the 2nd nonwoven fabric sheet 21 is demonstrated in detail.
The 2nd nonwoven fabric sheet 21 is the nonwoven fabric extended | stretched using the tooth gap roll mentioned later. For example, as shown in FIG. 4, the second non-woven fabric sheet 21 before shaping is a corrugated fiber sheet 30. That is, it is a nonwoven fabric in which straight ridges 31 and straight ridges 32 are alternately and repeatedly arranged. As for the 2nd nonwoven fabric sheet 21 used for the said embodiment, the protruding item | line part 31 and the protruding item | line part 32 which are extended in ay direction are distribute | arranged alternately by the x direction. As shown in FIG. 5, the fiber sheet 30 viewed in cross section is divided into three equal parts with the thickness in the Z direction. That is, an upper portion in the thickness direction (Z direction) is a top region 30a, a central portion in the thickness direction (Z direction) is a side region 30c, and a lower portion in the thickness direction (Z direction) is a bottom region 30b.
As will be described later, not only the side region 30c but also the top region 30a of the ridge 31 and the bottom region 30b of the dent 32 are stretched by the fiber sheet 30 by stretching. Therefore, the fiber density of the whole nonwoven fabric has fallen rather than the raw material nonwoven fabric before extending | stretching. Thereby, the liquid permeability of the whole fiber sheet 30 and air permeability are improving. In particular, the fiber density of the side region 30c that is easily stretched is the lowest, and the liquid permeability and air permeability are particularly improved. On the other hand, the fiber density is high in the top region 30a and the bottom region 30b.
High fiber density means that the amount of fibers present per unit volume of the fiber sheet 30 is large and the distance between the fibers is short. Low fiber density means that the amount of fibers present per unit volume of the fiber sheet 30 is small and the inter-fiber distance is long. And the site | part with high fiber density has high capillary force, and the site | part with low fiber density has low capillary force.

  The second nonwoven fabric sheet 21 is formed by applying a high-speed air current to the fiber sheet 30 supported by a support described later. The corrugated shape of the fiber sheet 30 is extended during shaping. Therefore, the corrugated shape of the fiber sheet 30 does not remain on the second nonwoven fabric sheet 21. The 2nd nonwoven fabric sheet 21 is made into a corrugated sheet shape by the shaping process mentioned later. In other words, the third protruding portion 22 of the ridge protruding in the first surface side Z1 and continuing in the y direction and the fourth protruding portion 24 of the ridge protruding in the second surface side Z2 and continuing in the y direction are in the x direction. Alternatingly arranged. Therefore, as shown in FIG. 6, in the xz cross section, the second nonwoven fabric sheet 21 repeatedly appears densely and densely. That is, the fiber density of the top region 30a and the bottom region 30b of the fiber sheet 30 is dense H, and the fiber density of the side region 30c is sparse L. Thereby, the density of the second nonwoven fabric sheet 21 appears alternately in the x direction. As shown in the figure, the fourth protrusion 24 is not necessarily dense and the third protrusion 22 is not sparse. The fourth protrusion 24 may be sparse and the third protrusion 22 may be dense.

It is preferable that the fiber used for the 2nd nonwoven fabric sheet 21 has a site | part from which a fiber diameter differs. For example, as shown in FIG. 7, attention is focused on one fiber 34 in the constituent fiber group of the second nonwoven fabric sheet 21. Between the fused parts 35 and 35 formed by fusing the fibers 34 with other fibers, there are two small-diameter parts 36 and 36 that are drawn narrower than the original fiber diameter. Further, a large diameter portion 37 is provided between the small diameter portions 36 and 36. In the illustrated example, the small-diameter portions 36 and 36 are connected to the fusion-bonding portions 35 and 35, respectively, and a large-diameter portion 37 having a fiber diameter larger than the small-diameter portion 36 is between the small-diameter portions 36 and 36. It is arranged. The large-diameter portion 37 is a portion having the original fiber diameter of the fiber, and is a portion having a relatively larger fiber diameter than the small-diameter portion 36 thinned by stretching. The number of large-diameter portions 37 is not limited to this between the fused portions 35 and 35, and a form having a plurality of large-diameter portions 37 may be used. In this case, since the small diameter portions 36 are arranged on both sides of each large diameter portion 37, the number of the small diameter portions 36 is determined in accordance with the number of large diameter portions 37.
In the configuration of the fiber 34, a small-diameter portion 36 having a rigidity lower than that of the large-diameter portion 37 is disposed adjacent to the fusion-bonding portion 35 with increased rigidity. Thereby, the softness | flexibility of the 2nd nonwoven fabric sheet 21 containing the fiber 34 improves, and combined with the form of the 1st nonwoven fabric sheet 11, the touch of the laminated nonwoven fabric 10 whole becomes favorable.

  It is preferable to have one or more large-diameter portions 37 between the fused portions 35 and 35 from the viewpoint of preventing the nonwoven fabric strength from being lowered. Moreover, it is preferable to have 5 or less large diameter parts 37, and it is more preferable to have 3 or less. Specifically, the number of large-diameter portions 37 is preferably 1 or more and 5 or less, and more preferably 1 or more and 3 or less.

The ratio (L36 / L37) of the fiber diameter (diameter L36) of the small diameter portion 36 to the fiber diameter (diameter L37) of the large diameter portion 37 is preferably 0.5 or more, more preferably 0.55 or more. And preferably it is 0.8 or less, More preferably, it is 0.7 or less. More specifically, it is preferably 0.5 or more and 0.8 or less, and more preferably 0.55 or more and 0.7 or less.
The fiber diameter of the small-diameter portion 36 is preferably 5 μm or more, more preferably 6.5 μm or more, and particularly preferably 7.5 μm or more from the viewpoint of improving the touch and suppressing the decrease in nonwoven fabric strength. And it is preferably 28 μm or less, more preferably 20 μm or less, and particularly preferably 16 μm or less. More specifically, it is preferably 5 μm or more and 28 μm or less, more preferably 6.5 μm or more and 20 μm or less, and particularly preferably 7.5 μm or more and 16 μm or less.
The fiber diameter of the large diameter portion 37 is preferably 10 μm or more, more preferably 13 μm or more, and particularly preferably 15 μm or more from the viewpoint of improving the touch. And it is preferably 35 μm or less, more preferably 25 μm or less, and particularly preferably 20 μm or less. More specifically, it is preferably 10 μm to 35 μm, more preferably 13 μm to 25 μm, and particularly preferably 15 μm to 20 μm.

  The fiber diameters (diameters L36 and L37) of the small diameter part 36 and the large diameter part 37 can be measured by the following method. That is, the fiber diameter of a fiber measures the diameter (micrometer) of a fiber by enlarging the cross section of a fiber 200 times-800 times using a scanning electron microscope (JEOL Co., Ltd. JCM-5100). The cross section of the fiber is obtained by cutting the fiber using a feather razor (product number FAS-10, manufactured by Feather Safety Razor Co., Ltd.). For one extracted fiber, the fiber diameter when the cross section is approximated to a circle is measured at five locations, and the average value of the five measured values is taken as the fiber diameter.

  Such fibers 34 preferably occupy 20% or more of the entire constituent fibers of the second nonwoven fabric sheet 21, more preferably 50% or more, and particularly preferably 100%.

Next, the fiber structure of the second nonwoven fabric sheet 21 will be described.
Moreover, in the 2nd nonwoven fabric sheet 21, it is preferable that the contact angles of the site | parts from which the fiber diameter which has in the same fiber differs mutually differ. Specifically, the contact angle of the small diameter portion 36 is preferably larger than the contact angle of the large diameter portion 37 between the small diameter portion 36 and the large diameter portion 37 shown in FIG. This “contact angle” is a fiber contact angle measured by the method described below. The value of the contact angle indicates the degree of “hydrophilicity” of the fiber. Specifically, a large contact angle is synonymous with low hydrophilicity, and a small contact angle is synonymous with high hydrophilicity. Therefore, it is preferable that the hydrophilicity of the small diameter portion 36 is lower than the hydrophilicity of the large diameter portion 37 because the contact angle of the small diameter portion 36 is larger than the contact angle of the large diameter portion 37.

  In the 2nd nonwoven fabric sheet 21, the excessive expression of the liquid diffusion along this fiber is suppressed because the small diameter part 36 and the large diameter part 37 coexist in the same fiber, and have the said contact angle difference. Yes. This works particularly effectively when pressure is applied to the laminated nonwoven fabric 10 from the first surface side Z1. That is, the liquid which has permeated through the second nonwoven fabric sheet 21 after being excreted and once stalled again heads toward the first surface side Z1 with the above pressure. However, it is difficult for the liquid to travel through the fibers due to the discontinuity of the fiber diameter and hydrophilicity on the first surface side Z1. For this reason, it becomes difficult to return the liquid. On the other hand, the excretion fluid having a flow rate during excretion is easily driven by the structure of the fibers 34 due to the momentum, and is easily dispersed and collected in the internal space 23 side of the third protrusion 22. In addition, the liquid having a flow velocity is not repelled in the second non-woven fabric sheet 21 because the liquid having a flow velocity is over the hydrophobic portion and is water-repellent. Thereby, when arrange | positioning as a surface sheet toward the 1st surface side Z1 of the laminated nonwoven fabric 10 toward the skin surface side, reduction of a liquid return can be implement | achieved and it is preferable.

The contact angle is measured by the following method.
First, a plurality of constituent fibers of the second nonwoven fabric sheet 21 are extracted at random. From the extracted constituent fibers, constituent fibers having a small diameter portion 36 and a large diameter portion 37 are selected, and the contact angles of water at the positions of the small diameter portion 36 and the large diameter portion 37 in the constituent fibers are measured. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Distilled water is used to measure the contact angle.
The amount of liquid discharged from the ink jet type water droplet discharge unit is set to 15 picoliters. A pulse injector CTC-25 manufactured by Cluster Technology Co., Ltd. and having a discharge part pore diameter of 25 μm was used for the ink jet type water droplet discharge part. Then, a water droplet is dropped just above the center of each of the position of the small diameter portion 36 and the position of the large diameter portion 37.
The state of dripping is recorded on a high-speed recording device connected to a horizontally installed camera. The recording device is preferably a personal computer incorporating a high-speed capture device from the viewpoint of image analysis later. In this measurement, an image is recorded every 17 msec. In the recorded image, the first image in which water droplets have landed on the selected constituent fibers is subjected to image analysis using the attached software FAMAS. The software version is 2.6.2. The analysis method is a droplet method, and the analysis method is the θ / 2 method. Assume that the image processing algorithm is non-reflective, the image processing image mode is frame, the threshold level is 200, and curvature correction is not performed. Based on the image analysis, the angle formed by the fiber and the surface of the water droplet that contacts the air is calculated as the contact angle. The selected constituent fibers are cut to a fiber length of about 1 mm, and the fibers are placed on a sample table of a contact angle meter and kept horizontal. For the small-diameter portion 36 and the large-diameter portion 37 of one fiber, two contact angles at different positions are measured. The contact angles of N = 5 small diameter portions 16 and large diameter portions 17 are measured to one decimal place. A value obtained by averaging the measured values at a total of 10 locations (rounded to the first decimal place) is defined as the contact angle of the small diameter portion 36 and the large diameter portion 37.

From the viewpoint of reducing the liquid residue on the surface of the second nonwoven fabric sheet 21 and improving the dry feeling, the difference between the contact angle of the small diameter portion 36 and the contact angle of the large diameter portion 37 (the former-the latter) is preferably 1 degree or more, 5 degrees or more is more preferable, and 10 degrees or more is more preferable. And 25 degrees or less are preferable, 20 degrees or less are more preferable, and 15 degrees or less are more preferable. More specifically, the difference in contact angle is preferably 1 degree or more and 25 degrees or less, more preferably 5 degrees or more and 20 degrees or less, and further preferably 10 degrees or more and 15 degrees or less.
The contact angle of the small diameter portion 36 is preferably 60 degrees or more, more preferably 70 degrees or more, and further preferably 80 degrees or more. And 100 degrees or less are preferable, 95 degrees or less are more preferable, and 90 degrees or less are more preferable. More specifically, the contact angle of the small diameter portion 16 is preferably 60 degrees or more and 100 degrees or less, more preferably 70 degrees or more and 95 degrees or less, and further preferably 80 degrees or more and 90 degrees or less.
The contact angle of the large diameter portion 37 is preferably 55 degrees or more, more preferably 60 degrees or more, and further preferably 65 degrees or more. And 90 degrees or less are preferable, 85 degrees or less are more preferable, and 80 degrees or less are more preferable. More specifically, the contact angle of the large-diameter portion 37 is preferably 55 degrees or more and 90 degrees or less, more preferably 60 degrees or more and 85 degrees or less, and further preferably 65 degrees or more and 80 degrees or less.

Next, the fiber material of the laminated nonwoven fabric will be described.
In the laminated nonwoven fabric 10, as the constituent fibers of the first nonwoven fabric sheet 11 and the second nonwoven fabric sheet 21, fiber materials used for ordinary nonwoven fabrics can be used without particular limitation. Examples thereof include the fiber materials described in paragraph [0032] of JP2012-136791A, paragraph [0034] of JP2012-149371A, and the like.

  Furthermore, since the constituent fibers of the second nonwoven fabric sheet 20 have the above-described structures of the small diameter portion 36 and the large diameter portion 37 in the same fiber, it is preferable to include high elongation fibers. The “high elongation fiber” means a fiber having a specific elongation performance, and specifically means a fiber having a fiber elongation at break of 100% or more. The “high elongation fiber” means not only a fiber having a high elongation at the raw fiber stage but also a fiber having a high elongation at the stage of the laminated nonwoven fabric 10 produced. Examples of the “high elongation fiber” include those described in paragraph [0033] of Japanese Patent Application Laid-Open No. 2010-168715 except for elastic fibers that have elasticity (elastomer) and expand and contract. Specifically, heat-extensible fibers obtained by melt spinning at low speed to obtain composite fibers and then performing either one or both of heat treatment and crimping treatment without performing drawing treatment can be mentioned. This heat-extensible fiber is a fiber whose length is increased by changing the crystalline state of the resin by heating. Moreover, the fiber manufactured on conditions with comparatively low spinning speed using resin, such as a polypropylene and polyethylene, is mentioned. In addition, a polyethylene-polypropylene copolymer having a low crystallinity, or fibers produced by dry blending and spinning polyethylene into polypropylene, and the like can be given. Among these fibers, the form of the high elongation fiber is preferably a core-sheath type composite fiber having heat fusion properties. The core-sheath type composite fiber may be a concentric core-sheath type, an eccentric core-sheath type, a side-by-side type, or a deformed type, and a concentric core-sheath type is particularly preferable. The fineness of the high elongation fiber is preferably 1.0 dtex or more, more preferably 2.0 dtex or more at the raw material stage in any of the above fiber forms, from the viewpoint of making the nonwoven fabric soft and comfortable. The fineness of the high elongation fiber is preferably 10.0 dtex or less, and more preferably 8.0 dtex or less. More specifically, the fineness of the high elongation fiber is preferably 1.0 dtex or more and 10.0 dtex or less, and more preferably 2.0 dtex or more and 8.0 dtex or less.

  In the 2nd nonwoven fabric sheet 21, it is preferable to be comprised only from an inelastic fiber, and it is still more preferable to be comprised only from the high elongation fiber. In addition to the high elongation fiber, other fibers may be included. Other fibers include, for example, a non-heat-extensible core-sheath type heat-fusible composite fiber that includes two components having different melting points and is stretched, or a fiber that does not inherently have heat-fusibility Is mentioned. Examples of fibers that do not have heat-fusibility include natural fibers such as cotton and pulp, rayon, and acetate fibers. In the case where the nonwoven fabric includes other fibers in addition to the high elongation fibers, the proportion of the high elongation fibers in the nonwoven fabric is preferably 50% by mass or more, and more preferably 80% by mass or more. And preferably it is 100 mass% or less. More specifically, it is preferably 50% by mass or more and 100% by mass or less, and more preferably 80% by mass or more and 100% by mass or less.

  A heat-extensible fiber, which is an example of a high-stretch fiber, is a composite fiber that has been unstretched or weakly stretched at the raw material stage. For example, it has the 1st resin component which comprises a core part, and the 2nd resin component containing a polyethylene resin which comprises a sheath part. The first resin component has a higher melting point than the second resin component. A 1st resin component is a component which expresses the heat | fever extensibility of this fiber, and a 2nd resin component is a component which expresses heat-fusibility. The melting points of the first resin component and the second resin component are defined by the melting peak temperature. The melting peak temperature of each resin is measured using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.). Specifically, thermal analysis of a finely cut fiber sample (sample weight 2 mg) is performed at a temperature rising rate of 10 ° C./min, and the melting peak temperature of each resin is measured and obtained. When the melting point of the second resin component cannot be clearly measured by this method, the resin is defined as “resin having no melting point”. In this case, the temperature at which the second resin component is fused to such an extent that the strength of the fusion point of the fiber can be measured is used as the temperature at which the molecular flow of the second resin component begins, and this is used instead of the melting point.

As above-mentioned, as a 2nd resin component which comprises a sheath part, the polyethylene resin is included. Examples of the polyethylene resin include low density polyethylene (LDPE), high density polyethylene (HDPE), and linear low density polyethylene (LLDPE). In particular, a high density polyethylene having a density of 0.935 g / cm ³ or more and 0.965 g / cm ³ or less is preferable. The second resin component constituting the sheath is preferably a polyethylene resin alone, and other resins can also be blended. Other resins to be blended include polypropylene resin, ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), and the like. However, as for the 2nd resin component which comprises a sheath part, it is preferable that 50 mass% or more in the resin component of a sheath part is 70 to 100 mass% especially polyethylene resin. The crystallite size of the polyethylene resin is preferably 10 nm or more, and more preferably 11.5 nm or more. And 20 nm or less is preferable and 18 nm or less is more preferable. More specifically, it is preferably 10 nm or more and 20 nm or less, and more preferably 11.5 nm or more and 18 nm or less.

  As a 1st resin component which comprises a core part, the resin component whose melting | fusing point is higher than the polyethylene resin which is a constituent resin of a sheath part can be especially used without a restriction | limiting. Examples of the resin component constituting the core part include polyolefin resins (excluding polyethylene resin) such as polypropylene (PP), polyester resins, and the like. Examples of the polyester resin include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT). Furthermore, a polyamide polymer, a copolymer having two or more resin components, and the like can also be used. A plurality of types of resins can be blended and used. In that case, the melting point of the core is the melting point of the resin having the highest melting point. Since the production of the nonwoven fabric becomes easy, the difference (the former-the latter) between the melting point of the first resin component constituting the core part and the melting point of the second resin component constituting the sheath part is 20 ° C. or higher. It is preferable that it is 150 degrees C or less.

The preferred orientation index of the first resin component in the heat-extensible fiber, which is an example of a high elongation fiber, is naturally different depending on the resin used. For example, when the first resin component is a polypropylene resin, the orientation index is preferably 60% or less, more preferably 40% or less, and even more preferably 25% or less. When the first resin component is polyester, the orientation index is preferably 25% or less, more preferably 20% or less, and even more preferably 10% or less.
On the other hand, the orientation index of the second resin component is preferably 5% or more, more preferably 15% or more, and further preferably 30% or more. The orientation index is an index of the degree of orientation of the polymer chain of the resin constituting the fiber.

  The orientation index of the first resin component and the second resin component is determined by the method described in paragraphs [0027] to [0029] of JP2010-168715A. Moreover, the method in which each resin component in the heat-extensible fiber achieves the orientation index as described above is described in paragraphs [0033] to [0036] of JP-A No. 2010-168715.

  The elongation of the high elongation fiber is preferably 100% or more, more preferably 200% or more, and further preferably 250% or more at the raw material stage. And preferably it is 800% or less, More preferably, it is 500% or less, More preferably, it is 400% or less. More specifically, it is preferably 100% or more and 800% or less, more preferably 200% or more and 500% or less, and further preferably 250% or more and 400% or less. By using the high elongation fiber having the elongation in this range, the fiber is successfully stretched in the stretching apparatus, and the change point 38 from the small diameter portion 36 to the large diameter portion 37 is adjacent to the fusion portion 35. And feel better.

  The elongation of the high elongation fiber conforms to JISL-1015. Measurement environment temperature / humidity 20 ± 2 ° C., 65 ± 2% RH, tensile tester gripping distance 20 mm, tensile speed 20 mm / min. When the gripping interval cannot be 20 mm, the gripping interval is set to 10 mm or 5 mm for measurement. The measurement is performed by shortening the gripping interval when collecting fibers from an already produced nonwoven fabric and measuring the elongation, or when the length of the fibers to be measured is less than 20 mm.

  The ratio (mass ratio, former: latter) of the first resin component and the second resin component in the high elongation fiber is preferably 10:90 to 90:10 at the raw material stage. Furthermore, the ratio is more preferably 20:80 to 80:20, and further preferably 50:50 to 70:30. As the fiber length of the high elongation fiber, one having an appropriate length is used according to the method for producing the nonwoven fabric. For example, when the nonwoven fabric is manufactured by the card method, the fiber length is preferably about 30 mm to 70 mm.

  The fiber diameter of the high elongation fiber is appropriately selected depending on the specific use of the nonwoven fabric at the raw material stage. When the nonwoven fabric is used as a constituent member of an absorbent article such as a surface sheet of the absorbent article, the fiber diameter of the high elongation fiber is preferably 10 μm or more, and particularly preferably 15 μm or more. And 35 micrometers or less are preferable and 30 micrometers or less are especially preferable. More specifically, it is preferably 10 μm or more and 35 μm or less, and particularly preferably 15 μm or more and 30 μm or less. The fiber diameter is measured by the method used in the measurement of the small diameter portion 36 and the large diameter portion 37 described above.

  In the raw material stage, when using a heat-extensible fiber that is an example of a high-stretch fiber, fibers described in the following patent publication can be used in addition to the above-described heat-extensible fiber. That is, it is described in Japanese Patent No. 4131852, Japanese Unexamined Patent Application Publication No. 2005-350836, Japanese Unexamined Patent Application Publication No. 2007-303035, Japanese Unexamined Patent Application Publication No. 2007-204899, Japanese Unexamined Patent Application Publication No. 2007-204901, Japanese Unexamined Patent Application Publication No. 2007-204902, and the like. Of fiber.

Moreover, in order to form the small diameter part 36 and the large diameter part 37 using a high elongation fiber, and to make the contact angle of the small diameter part 36 larger than the large diameter part 37, the fiber treatment agent may adhere. preferable.
That is, it is preferable that the fiber treatment agent is attached to the surface of the high elongation fiber in the constituent fiber at the raw material stage. The fiber treatment agent preferably contains a spreadable component, and more preferably contains a spreadable component and a hydrophilic component. Here, the spreadable component refers to a component that, when attached to the surface of the fiber, easily spreads on the surface of the fiber at a low temperature and has excellent fluidity at a low temperature. Examples of such a spreadable component include a silicone resin having a low glass transition point and a flexible molecular chain. As the silicone resin, polyorganosiloxane having a Si—O—Si chain as a main chain is preferably used. The spreadable component is easy to spread when the fiber is stretched, and the hydrophilic component is difficult to spread. From this, when the fiber treatment agent adhering to the fiber surface contains a spreadable component and a hydrophilic component, it is considered that the hydrophilicity of the stretched portion of the fiber changes.

  As the hydrophilic component, a zwitterionic surfactant or a nonionic surfactant can be used.

  Examples of the zwitterionic surfactant include betaine-type zwitterionic surfactants, amino acid-type amphoteric surfactants, and aminosulfonic acid-type amphoteric surfactants. Among them, betaine-type zwitterionic surfactants are preferable, alkyl (C1-30) betaines are more preferable, and alkylbetaines having 16 to 22 carbon atoms (for example, stearyl) are particularly preferable.

  Examples of the nonionic surfactant include polyhydric alcohol fatty acid esters (both preferably fatty acid having 8 to 60 carbon atoms). Moreover, polyoxyalkylene (addition mole number 2-20) alkyl (carbon number 8-22) amide is mentioned as nonionic surfactant. Furthermore, polyoxyalkylene (addition mole number 2 to 20) alkyl (carbon number 8 to 22) ether, polyoxyalkylene-modified silicone, amino-modified silicone and the like can be mentioned.

  The fiber treatment agent preferably contains a hydrophobic component in addition to the spreadable component and the hydrophilic component. Examples of the hydrophobic component include alkyl phosphate esters, anionic surfactants represented by the following general formula (1) (hereinafter also simply referred to as “anionic surfactants”), and the like.

(In the formula, Z represents a linear or branched alkyl chain having 1 to 12 carbon atoms. An ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group or a double bond may be included. R ¹ and R ² each represent a linear or branched alkyl group having 2 to 16 carbon atoms, each independently including an ester group, an amide group, a polyoxyalkylene group, an ether group or a double bond. X represents —SO ₃ M, —OSO ₃ M or COOM, where M represents H, Na, K, Mg, Ca or ammonium.)

Next, the manufacturing method of a laminated nonwoven fabric is demonstrated.
In the air-through method, the laminated nonwoven fabric 10 can be manufactured by controlling the temperature and the wind speed of the hot air to be blown and performing a shaping process and a heat-sealing process. For example, the method described in paragraph [0031] of JP2012-136790A can be used. Alternatively, the method described in paragraphs [0033] to [0061] of JP2012-149371A can be used. Examples of the support used for shaping include the support shown in FIGS. 1 and 2 of JP 2012-149370 A, the support shown in FIGS. 1 to 4 of JP 2012-149371 A, and the like. .

The above processing will be described in detail with reference to FIG.
As shown in FIG. 8, the manufacturing method using the support body 100 is demonstrated as an example. The support body 100 includes a plurality of rod-like bodies 101, a plurality of protrusions 102 that are spaced apart from each other, and a plurality of holes 103 that are surrounded by the plurality of protrusions 102. As this support body 100, the thing of FIG. 1 of Unexamined-Japanese-Patent No. 2012-149371, etc. are mentioned, for example.
First, the stretched second nonwoven sheet 21 is prepared in advance by a method described later.
Subsequently, the fiber web 50 before fiber fusion used as a raw material of the first nonwoven fabric sheet 11 is conveyed toward the support body 100 together with the second nonwoven fabric sheet 21 while being formed by a card machine. At that time, the fiber web 50 and the second nonwoven fabric sheet 21 are laminated in this order on the protrusions 102 of the support 100. Here, the direction perpendicular to the direction in which the third projecting portion 22 of the second nonwoven fabric sheet 21 extends in a bowl shape and the direction in which the fourth projecting portion 24 extends in the shape of a groove in the internal space 25 is defined as the transport direction. Therefore, FIG. 8 shows a side surface viewed from a direction perpendicular to the conveyance direction of each sheet, and the left-right direction of the drawing is the sheet conveyance direction (MD). The direction from the back of the drawing perpendicular to this to the front is the sheet width direction (CD). Of the three protrusions 102 of the support body 100 shown in FIG. 8, the central one is arranged behind the two left and right ones.

  In this state, the hot air W (indicated by a broken arrow) is sprayed from the second nonwoven fabric sheet 21 side while controlling the temperature and the wind speed. That is, the hot air W passes from the fiber sheet 30 through the fiber web 50 and passes through the hole 103 of the support 100, and performs a shaping process and a heat-sealing process. Thereby, the fiber web 50 which is not melt | fused is shaped along the unevenness | corrugation of the support body 100, and is heat-seal | fused, and the 1st nonwoven fabric sheet 11 is formed.

  The 1st protrusion part 12 of the 1st nonwoven fabric sheet 11 is comprised in the part which penetrates the hole 103 of the support body 100, and a fiber density becomes sparse rather than the time of a web by passage of a hot air, and is shape | molded softly. On the other hand, the second protrusion 14 is formed at a portion supported by the protrusion 102 of the support, does not pass hot air, and has a higher fiber density than the first protrusion 12. Furthermore, a density gradient in which the fiber density increases from the first projecting portion 12 toward the second projecting portion 14 due to the strength of the influence of the passage of hot air. Further, the wall portion 16 that connects the first projecting portion 12 and the second projecting portion 14 is formed into an annular shape by shaping at the hole 103 surrounding the four sides of the protrusion 102. In addition, the orientation of the fibers changes in the direction of blown hot air by shaping before fusing. Therefore, the fiber orientation in the standing direction of the wall portion 16 is obtained at any of the MD and CD of the wall portion 16 and the intermediate positions thereof.

On the other hand, the 2nd nonwoven fabric sheet 21 is shaped so that the shape of the support body 100 may be followed. The fiber sheet 30 to be the second nonwoven fabric sheet 21 is previously stretched, and the ridges 31 and the ridges 32 are alternately arranged in the y direction (CD).
Since the fiber sheet 30 is thus arranged, the fiber sheet 30 is deformed along the shaping of the fiber web 50. At that time, in the fiber sheet 30, the protruding strip portion 31 and the concave strip portion 32 are extended, and the extended portion becomes the fourth protruding portion 24. However, since the corrugated plate portion 31 and the concave strip portion 32 form a corrugated plate shape, a force to maintain the corrugated plate shape acts against the wind force generated by hot air during shaping. Therefore, as shown in FIG. 3 described above, a gentle uneven shape is formed in the third protrusion 22 in the y direction (CD).
Moreover, the pressure accompanying a hot air is applied to the part of the 1st nonwoven fabric sheet 11 and the 2nd nonwoven fabric sheet 21 which were supported by the processus | protrusion 102. FIG. Therefore, the 4th protrusion part top part 24T of the 2nd nonwoven fabric sheet 21 and the 2nd protrusion part top part 14T of the 1st nonwoven fabric sheet 11 are crushed and joined. As a result, the second protrusion top 14T is brought into close contact with and integrated with the first surface side Z1 (back surface side) of the fourth protrusion 24.
As described above, the first nonwoven fabric sheet 11 and the second nonwoven fabric sheet 21 are shaped by hot air treatment. Thereby, each fiber density of the 1st nonwoven fabric sheet 11 and the 2nd nonwoven fabric sheet 21 becomes the highest density in the junction part of the 2nd protrusion part top part 14T and the 4th protrusion part top part 24T.

Next, the manufacturing method of the 2nd nonwoven fabric sheet 21 is demonstrated below.
As described above, in the method for manufacturing the laminated nonwoven fabric 10, the second nonwoven fabric sheet 21 is prepared in advance. The preferable manufacturing method of the 2nd nonwoven fabric sheet 21 is demonstrated below.
The manufacturing method includes a fusion process in which the intersections of the constituent fibers of the fiber web are thermally fused, and a stretching process in which the fused fiber web is stretched in one direction to form a streak-like uneven shape. From the viewpoint of forming the small-diameter portion 36 and the large-diameter portion 37 of the fiber in the drawing process, the fiber web preferably contains high elongation fibers to which the above-described fiber treatment agent is applied. Hereinafter, it demonstrates as what contains a high elongation fiber.

  In the fusing process, hot air is blown by an air-through method while conveying the fiber web 30B formed by a web forming apparatus such as a card machine or an airlaid apparatus. Thereby, the state where the fibers of the fiber web 30B are loosely intertwined further proceeds. At the same time, the intersecting points of the intertwined fibers are heat-sealed to form a fiber sheet 30 having a sheet-like shape retaining property.

  The temperature of the hot air and the heat treatment time are preferably adjusted so that the intersections of the high elongation fibers included in the constituent fibers of the fiber web 30B are thermally fused. Specifically, the temperature of the hot air is preferably adjusted to a temperature higher by 0 ° C. to 30 ° C. than the melting point of the resin having the lowest melting point among the constituent fibers of the fiber web 30B. The heat treatment time is preferably adjusted from 1 second to 5 seconds depending on the temperature of the hot air. Further, from the viewpoint of promoting further entanglement between the constituent fibers, the wind speed of the hot air is preferably about 0.3 m / sec to 1.5 m / sec. Further, the conveyance speed is preferably about 5 m / min to 100 m / min.

  In the stretching process, the fiber sheet 30 obtained in the fusion process is stretched in one direction. Specifically, as shown in FIGS. 9 and 10, the fiber sheet 30 is conveyed to meshing portions of the pair of concave and convex rolls 301 and 302 where the convex portions 303 and the convex portions 304 are alternately arranged. Thereby, the convex part 303 and the convex part 304 are pushed in the opposite direction with respect to the fiber sheet 30, and the fiber sheet 30 is shaped in a corrugated form. At this time, the fiber sheet 30 is stretched between the portion in contact with the top portion 303A of the convex portion 303 and the portion in contact with the top portion 304A of the convex portion 304, including both contact portions. By stretching, as shown in FIG. 7, two small-diameter portions 36, 36 having a fiber diameter smaller than the fiber diameter before stretching are formed on one constituent fiber 34 between adjacent fused portions 35, 35. The At the same time, a large diameter portion 37 having a fiber diameter larger than that of the small diameter portion 36 is formed between the small diameter portions 36 and 36. Specifically, local contraction is likely to occur first in the vicinity of each fused portion 35 of the constituent fiber 34. As a result of this local contraction, two small-diameter portions 36 and 36 are formed at both ends of one constituent fiber 34 between the adjacent fusion portions 35 and 35. A portion sandwiched between the two small diameter portions 36 and 36 becomes a large diameter portion 37 having a diameter larger than that of the small diameter portion 36. In this manner, the large-diameter portion 17 sandwiched between the two small-diameter portions 36 and 36 is formed. Furthermore, the large diameter part 37 between the adjacent fused parts 35 and 35 is stretched, and the small diameter part 36 is formed in the large diameter part 37.

  In the above-described stretching, the changing point 38 from the small diameter portion 36 to the large diameter portion 37 is arranged within a range of 1/3 of the interval T between the adjacent fusion portions 35, 35 close to the fusion portion 35. That is, the change point 38 is arranged in the range of T1 and T3 shown in FIG. The arrangement of the change points 38 is preferable from the viewpoint of a softer touch. In addition, said change point 38 means the site | part to which a fiber diameter changes extremely. Therefore, the part which changes gradually from the small diameter part 36 extended with a small fiber diameter to the large diameter part 37 extended with a fiber diameter larger than the small diameter part 36 is not included. Further, a portion that continuously changes from the small diameter portion 36 to the large diameter portion 37 over a plurality of stages is not included. Moreover, the change point 38 in the case where the drawn fiber is a core-sheath type composite fiber is a state in which the fiber diameter is changed by peeling the second resin component constituting the sheath from the first resin component constituting the core. Not included. To the last, it means a part where the fiber diameter is changed by stretching.

In the uneven rolls 301 and 302 shown in FIGS. 9 and 10, the convex portions 303 and the convex portions 304 are arranged along the width direction on the respective roll peripheral surfaces. In addition, a plurality of the convex portions 303 and the convex portions 304 are arranged at equal intervals in the respective roll circumferential directions. In this case, in the drawing process of the fiber sheet 30, the hook-shaped convex strip portion 31 and the groove-shaped concave strip portion 32 extending in the direction (CD) orthogonal to the transport direction (MD) are transport direction (MD). Alternately. That is, it is stretched in the MD direction to form a corrugated shape. The direction of stretching is not limited to this case, and may be a direction (CD) orthogonal to the conveyance. In this case, the stretching apparatus shown in FIG. 11 is used. In order to extend in the width direction, concavo-convex rolls 401 and 402 having tooth grooves cut at equal intervals in the roll circumferential direction are used. In the concavo-convex rolls 401 and 402, the convex portions 403 and the convex portions 404 are arranged along the circumferential direction on the respective circumferential surfaces of the rolls. In addition, a plurality of convex portions 403 and convex portions 404 are arranged at equal intervals in the respective roll width directions. In this case, the drawing process of the fiber sheet 30 is alternately performed in the direction (CD) in which the ridge-like convex strips 31 and the groove-shaped concave strips 32 extending in the transport direction (MD) are orthogonal to the transport direction. Is done. That is, it is stretched in the CD direction to form a corrugated shape.
Furthermore, even if the ridge-like ridges 31 and the groove-like ridges 32 of the fiber sheet 30 are formed obliquely with respect to the transport direction (MD) of the first nonwoven fabric sheet 21, for example, in a 45-degree direction. Good.

  In the above-described stretching process, the region between the adjacent fused portions 35 and 35 in one constituent fiber 34 is positively stretched. At that time, of the fiber treatment agent attached to the surface of the constituent fiber 34, the spreadable component is excellent in low-temperature fluidity. Therefore, the state of flowing with the elongation of the fiber and adhering to the surface of the small diameter portion 36 is maintained. On the other hand, of the fiber treatment agent attached to the surface of the constituent fiber 34, components other than the spreadable component cannot flow along with the elongation of the fiber, and the state attached to the surface of the small diameter portion 36 cannot be maintained. Therefore, the composition ratio of the attached fiber treatment agent changes on the surface of the small diameter portion 36 and the surface of the large diameter portion 37 formed by extending the region between the adjacent fusion portions 35 and 35. Specifically, only the spreadable component is likely to adhere to the surface of the small diameter portion 36. On the other hand, a fiber treatment agent containing a spreadable component and a hydrophilic component is attached to the surface of the large diameter portion 37. As a result, the hydrophilicity of the small diameter portion 36 tends to be smaller than the hydrophilicity of the large diameter portion 37. In particular, when the above-described polyorganosiloxane having extensibility is used, the hydrophilicity of the small-diameter portion 36 tends to be smaller than that of the large-diameter portion 37 because the polyorganosiloxane itself is hydrophobic.

  Such stretching is also performed in the stretching apparatus described above. Therefore, the fiber density of the entire sheet is lower than that before stretching. Among these, since the side region 30 </ b> C of the fiber sheet 30 is particularly easily stretched, the fiber density is made lower than that of the ridges 31 and the ridges 32.

In addition, it is preferable that the 2nd nonwoven fabric sheet 21 consists only of a high elongation fiber from a viewpoint which forms the small diameter part 36 and the large diameter part 37 in the same fiber, and makes soft touch favorable.
If elastic fibers are contained in the constituent fibers, the nonwoven fabric is stretched while being contracted. Therefore, even when the nonwoven fabric manufacturing method and the mechanical stretch ratio are the same, the fiber diameter hardly changes. Therefore, when an elastic fiber is contained in the constituent fibers, it is difficult to form a change point 38 that is a portion where the fiber diameter changes extremely. Instead, a portion that continuously and gradually changes from the small diameter portion 36 to the large diameter portion 37 is likely to be formed. The continuously and gradually changing portion formed in this way is not necessarily stretched locally near the fusion point because it contains elastic fibers. The local stretched part is observed randomly throughout the constituent fibers rather than near the fusion point. Also from this viewpoint, it is preferable that the constituent fibers do not contain elastic fibers.

According to the manufacturing method of the said 2nd nonwoven fabric sheet 21, it comprises the constituent fiber 34 shown in FIG. That is, the second nonwoven fabric sheet 21 in which the contact angle of the small diameter portion 36 is larger than the contact angle of the large diameter portion 37 (that is, the hydrophilicity is small) can be continuously and efficiently manufactured.
The manufactured second nonwoven fabric sheet 21 (fiber sheet 30) is once wound up into a roll form. Then, it rolls out from a roll and is laminated | stacked with the fiber web 50 used as the raw material of the 1st nonwoven fabric sheet 11, and the laminated nonwoven fabric 10 is formed.

  The laminated nonwoven fabric 10 of the present invention can be used for various other applications. For example, it can be suitably used as a surface sheet for absorbent articles such as diapers, sanitary napkins, panty liners, urine absorbing pads and the like. In addition, the form used as a wiping wipe sheet, a cleaning sheet, and a filter is also mentioned.

  Next, a preferred embodiment of an absorbent article using the laminated nonwoven fabric according to the present invention as a surface material (hereinafter also referred to as a surface sheet) will be described with reference to FIG. Specifically, an application example of the laminated nonwoven fabric to the main body 4 of the diaper 200 as an absorbent article will be described. The diaper shown in the figure is a tape-type baby diaper, and is shown in a state where the diaper developed in a plane is bent slightly and viewed from the inside (skin contact surface side). Further, the X direction of the diaper corresponding to the x direction in FIG. 1 indicates the width direction of the diaper, the Y direction of the diaper corresponding to the y direction in FIG. 1 indicates the longitudinal direction of the diaper, and corresponds to the z direction in FIG. The Z direction of a diaper shows the thickness direction of a diaper.

As shown in FIG. 12, the diaper 200 includes a liquid permeable top sheet 1, a liquid hardly permeable back sheet 2, and a liquid retaining absorbent 3. The top sheet 1 is arranged on the skin contact surface side. The back sheet 2 is arranged on the non-skin contact surface side. The absorber 3 is disposed between both sheets.
The laminated nonwoven fabric 10 of the said embodiment is applied to the surface sheet 1, The 1st protrusion part 12 side is made into the skin contact surface.

The back sheet 2 is in a developed state, and both side edges thereof have a shape constricted inward in the longitudinal central portion C, and may be composed of one or a plurality of sheets. The back sheet 2 is not particularly limited as long as it has waterproofness and moisture permeability.
As the absorbent body 3, various forms used for this type of article can be widely adopted as long as they have liquid retention. For example, there are various types such as those in which pulp fibers are coated with a core wrap sheet, sheets in which an airlaid nonwoven is used, and sheets in which a superabsorbent polymer is sandwiched between fiber sheets.
The core wrap sheet is a hydrophilic member. Examples thereof include thin paper (thin paper) such as hydrophilic tissue paper, crepe paper, and non-woven fabric.
In this example, the side seat 5 is arranged. As the side sheet 5, a water-repellent nonwoven fabric is preferable.
Further, a side leakage prevention gather 7 formed by the side seats 5 is provided, whereby side leakage of liquid or the like in the hip joint part due to movement of the infant can be effectively prevented. In the diaper of this embodiment, a functional structure part, a sheet material, etc. may be provided. In addition, in FIG. 12, the arrangement | positioning relationship and boundary of each member are not illustrated strictly, and if it is set as the general form of this kind of diaper, the structure will not be specifically limited.

The diaper is shown as a tape type, and a fastening tape 6 is provided on the flap portion on the back side R. Fastening tape 6 can be affixed to a tape affixing part (not shown) provided in the flap part of ventral side F, and a diaper can be mounted and fixed.
By applying the laminated nonwoven fabric 10 as the top sheet 1, the diaper 200 can achieve both prevention of liquid return on the skin contact surface, good touch and improvement of cushion feeling. Further, higher air permeability is obtained by the uneven shape of the laminated nonwoven fabric 10.

  The absorbent article of the present invention is not limited to the diaper of the above embodiment, and can be applied to, for example, sanitary napkins, panty liners, incontinence pads, urine collection pads, and the like. In addition to the top sheet 1, the back sheet 2, and the absorbent body 3, members may be incorporated as appropriate according to the purpose and function as constituent members of the absorbent article.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples in which a laminated nonwoven fabric was produced by the above-described laminated nonwoven fabric production method. The present invention is not limited to these examples. In this example, “part” and “%” are based on mass unless otherwise specified.

Example 1
As the laminated nonwoven fabric of Example 1, the one shown in FIG. 13 was produced.
First, the 2nd nonwoven fabric sheet 21 was produced with the following method.
As the constituent fiber, a fiber made only of ordinary elongation fiber and having no elasticity (elastomer) was used. Specifically, the normal elongation fiber was a concentric core-sheath composite fiber having a core part made of polyethylene terephthalate and a sheath part made of polyethylene. The ordinary elongation fiber had a fineness of 3.3 dtex and an elongation of 55%. The “ordinary elongation fiber” is a fiber having a specific elongation performance, and specifically means a fiber having a performance of 30% or more and less than 100%.
The web of the above constituent fibers was subjected to a fusion treatment by blowing hot air under the conditions of a temperature of 133 ° C., a wind speed of 0.7 m / sec, a treatment time of 30 seconds, and a processing speed of 5 m / min.

Next, stretching was performed using the rolls 301 and 302 shown in FIG. Specifically, the one in which the interval (pitch) between the convex portions included in the pair of concave and convex rolls 301 and 302 is 2.0 mm and the indentation depth t (see FIG. 10) is 1.2 mm is used. The machine draw ratio was 1.9 times. In addition, application | coating of the fiber treatment agent to a constituent fiber was performed before the extending process, and made the adhesion amount 0.47 mass%. The basis weight of the obtained second nonwoven fabric sheet 21 was 28 g / m ² and the thickness was 2.12 mm.
Next, the laminated nonwoven fabric 10 was produced using the support 100 as shown in FIG. 8 by combining the second nonwoven fabric sheet 21 with the fiber web 50 forming the first nonwoven fabric sheet 11. The pitch of the protrusions 102 on the support 100 was set to an MD pitch of 10 mm and a CD pitch of 3 mm.
For the fiber web 50 to be the first nonwoven fabric sheet 11, fibers having a fineness of 2.4 dtex, a core of polyethylene terephthalate and a sheath of polyethylene were used as constituent fibers. Using such a fiber, a fiber web 50 having a basis weight of 20 g / m ² was produced by a card machine. Next, as shown in FIG. 7, the second nonwoven fabric sheet 21 and the fiber web 50 were laminated on the protrusions 102 of the support 100. And the shaping process was performed by the 1st air through process, and the fusion | melting process of the constituent fibers was performed by the 2nd air through process.

In the first air-through process, the temperature of hot air was 110 ° C., the wind speed was 1.4 m / sec, the heat treatment time was 10 sec, and the processing speed was 5 m / min.
In the second air-through process, the temperature of hot air was 136 ° C., the wind speed was 0.7 m / sec, the heat treatment time was 30 sec, and the processing speed was 5 m / min.
The laminated nonwoven fabric 10 thus obtained had a two-layer structure as shown in FIG. 13 and had no openings, a basis weight of 48 g / m ² and a thickness of 5 mm.
Moreover, in the layer of the 2nd nonwoven fabric sheet 21, the small diameter part and the large diameter part were mixed in the same fiber. This was confirmed by a measuring method using the above-mentioned scanning electron microscope (JCM-5100 manufactured by JEOL Ltd.).
In addition, in the layer of the first nonwoven fabric sheet 11, the fiber density of the first protrusions 12 was lower than that of the second protrusions 14. This was confirmed by a measuring method using the above-mentioned scanning electron microscope (JCM-5100 manufactured by JEOL Ltd.).

(Example 2)
Example 2 was created by the same production method as Example 1 except that the following high elongation fiber was used for the second nonwoven fabric sheet 21.
As the constituent fiber, a fiber made of only a high elongation fiber and having no elasticity (elastomer) was used. Specifically, the high elongation fiber was a concentric core-sheath composite fiber having a core part made of polyethylene terephthalate and a sheath part made of polyethylene. The high elongation fiber had a fineness of 3.3 dtex and an elongation of 350%. The following composition was used as a fiber treatment agent to be adhered to the high elongation fiber.
The following composition was used as a fiber treatment agent to be adhered to the high elongation fiber.
Spreading component: polyorganosiloxane 5.0% by mass
Hydrophilic component: polyoxyethylene (POE) polyoxypropylene (POP) modified silicone 19.0 mass%
Polyoxyethylene (POE) alkylamide 28.5% by mass
Stearyl betaine 14.3% by mass
Hydrophobic component: alkyl phosphate ester 23.7% by mass
Anionic surfactant 9.5% by mass

(Comparative Example 1)
Comparative Example 1 was created by the same production method as Example 1 except that the second nonwoven fabric sheet 21 was not subjected to tooth gap processing.

[Measurement of thickness at 0.05 kPa pressure]
It measured using the thickness measuring device in the state which applied the load so that the pressure of 0.05 kPa might be applied. A laser displacement meter manufactured by OMRON Corporation was used as the thickness measuring instrument. The thickness was measured at 10 points, and the average value was calculated as the thickness.
[Measurement of thickness at 3kPa pressure]
It measured using the thickness measuring device in the state which applied the load so that the pressure of 3 kPa might be applied. A laser displacement meter manufactured by OMRON Corporation was used as the thickness measuring instrument. The thickness was measured at 10 points, and the average value was calculated as the thickness.

[Evaluation method of shape retention]
The following formula was used for calculation. Smaller numbers are less likely to be crushed and have compression resistance. That is, it was evaluated that there was shape retention.
{(Thickness at 0.05 kp) − (thickness at 3 kpa)} / thickness at 0.05 kpa × 100

[Measurement of liquid return amount]
The liquid return amount was measured using an infant diaper for evaluation. The baby diaper for evaluation was obtained by removing the surface sheet from the baby diaper as an example of the absorbent article 100, and using a test body of the laminated nonwoven fabric 10 instead, and fixing the periphery thereof. As a diaper for infants, a product made in 2012 by Marys Sarasara Air-Through (registered trademark) M size manufactured by Kao Corporation was used. In addition, the test body of the laminated nonwoven fabric 10 is hereinafter referred to as a non-woven fabric test body.
A pressure of 3 kPa was applied uniformly on the non-woven fabric test piece, a cylinder having a cross-sectional area of 1000 mm ² placed at the approximate center of the test piece was applied, and artificial urine was injected therefrom. As the artificial urine, physiological saline was used, and a total of 160 g of artificial urine was infused 4 times at a rate of 40 g every 10 minutes.
After standing for 10 minutes from the completion of the injection, the above cylinder and pressure were removed. Then, a weight adjusted so that a pressure of 3 kPa was applied to the absorbent sheet (mass = M1) was placed on the nonwoven fabric specimen around the injection point. For the absorbent sheet (mass = M1), filter paper No. 20 sheets of 5C (100 mm × 100 mm) were stacked and used.
After standing for 5 minutes, the weight was removed, the mass (M2) of the filter paper was measured, and the amount of liquid return was calculated according to the following equation.
Liquid return amount (g) = mass of filter paper after pressurization (M2) −mass of filter paper before pressurization (M1)

[Evaluation method of cushion feeling (compression recovery)]
The evaluation method of the cushion feeling used a KES compression tester (KES FB-3 manufactured by Kato Tech Co., Ltd.). The measurement was performed in an environment of 22 ° C. and 65% RH. The KES compression tester evaluated the compression characteristics up to 5.0 kPa in the normal mode, and read the RC value. As measurement values, three points were measured and the average value was defined as compression recovery. This KES compression tester is a plate having a circular plane with a compression area of 2 cm ² in area. The compression speed is 0.02 mm / sec and the maximum compression pressure is 5.0 kPa. When the maximum compression pressure is reached, the compression direction is reversed and the process proceeds to the recovery process. The RC value indicates the percentage of energy recovered relative to the energy during compression, and the greater the RC value, the better the resilience to compression and the greater the elasticity. The RC value in the compression property evaluation is a time integral value of pressure from a time T ₀ when an initial pressure of 0.05 kPa applied to a nonwoven fabric specimen is applied to a time T _m when a maximum pressure of 5.0 kPa is applied. The time integral value is divided by the work amount up to the maximum pressure of 5.0 kPa and expressed in%.

As is apparent from the results shown in Table 1, Examples 1 and 2 had compression resistances of 50% and 52%, and were not easily crushed in the thickness direction against high loads. Moreover, the liquid return amount was as small as 42 mg or less. In addition, the cushion feeling was excellent at 47.0 or more.
In the comparative example, since the second non-woven fabric sheet 21 was not subjected to tooth gap processing, the compression resistance was as high as 66% and was easily crushed. Moreover, the liquid return amount was as large as 61 mg. Furthermore, the cushion feeling was as low as 43.3%, and the compression recovery after a high load was applied was low.
As described above, it was found that Examples 1 and 2 were able to achieve excellent compression resistance, liquid return amount, and cushion feeling at the same time.

DESCRIPTION OF SYMBOLS 1 Top sheet 2 Back sheet 3 Absorber 4 Main body 5 Side sheet 6 Fastening tape 10 Laminated nonwoven fabric 11 1st nonwoven fabric sheet 12 1st protrusion part 12H Opening part 12T Top area | region (1st protrusion part top part)
13 Internal space 14 Second protrusion 14T Top region of second protrusion (second protrusion top)
DESCRIPTION OF SYMBOLS 15 Internal space 16 (16a, 16b), 26 Wall part 21 2nd nonwoven fabric sheet 22 3rd protrusion part 23 Internal space 24 4th protrusion part 24a, 24b Small convex part 25 Internal space 25B Bottom part area 30 Fiber sheet 30a Top part area 30b Bottom region 30c Side region 31 Convex part 32 Concave part 34 Fiber 35 Fusion part 36 Small diameter part 37 Large diameter part 38 Change point 30B, 50 Fiber web 100 Support body 101 Rod-like body 102 Protrusion 103 Hole 200 Diaper T Multilayer nonwoven fabric Thickness of T1 First nonwoven fabric sheet T2 Thickness of second nonwoven fabric sheet Z1 First surface side Z2 Second surface side 301, 301 Convex roll 303, 304 Convex part 303A, 304A Top part 401, 401 Concave roll 403, 404 Convex part

Claims (7)

A first protruding portion that protrudes on the first surface side of the nonwoven fabric in plan view and has an internal space on the second surface side opposite to the first surface side, and on the second surface side And a second projecting portion having an internal space on the first surface side, and a plurality of the first and second projecting portions alternately in different directions intersecting the nonwoven fabric in plan view. A first non-woven sheet arranged;
A third projecting portion continuously projecting in one direction on the first surface side and having an internal space continuous on the second surface side; and continuous in a direction along the one direction on the second surface side. And a fourth projecting portion having a continuous inner space on the first surface side, and the third and fourth projecting portions intersect the one direction in plan view of the nonwoven fabric. A plurality of second nonwoven sheets arranged alternately in the direction,
The second nonwoven fabric sheet is arranged on the second surface side of the first nonwoven fabric sheet, and the top region of the fourth projecting portion corresponding to the top region of the second projecting portion among the plurality of fourth projecting portions. A laminated nonwoven fabric in which the back surface side of the first protrusion and the top region of the second protrusion are joined.   The laminated nonwoven fabric according to claim 1, wherein the fourth protrusion has an uneven shape in the one direction. The first nonwoven fabric sheet has a higher fiber density of the second protrusion than the first protrusion,
3. The laminated nonwoven fabric according to claim 1, wherein the second nonwoven fabric sheet has density of fiber density alternately in a direction intersecting with the one direction. The second non-woven sheet contains high elongation fibers,
The fibers of the second nonwoven fabric sheet are fused together, and have fineness portions with different thicknesses between the fiber fusion points,
The laminated nonwoven fabric according to any one of claims 1 to 3, wherein among the fineness portions having different thicknesses, a thick fineness portion has a higher hydrophilicity than a thin fineness portion.   The laminated nonwoven fabric according to any one of claims 1 to 4, wherein an average fiber density of the first nonwoven fabric sheet is lower than an average fiber density of the second nonwoven fabric sheet.   Among the plurality of fourth protrusions, the internal space of the fourth protrusion that is not joined to the top region of the second protrusion is arranged corresponding to the position of the internal space of the first protrusion. The laminated nonwoven fabric according to any one of claims 1 to 5. An absorbent article having a liquid permeable top sheet, a back sheet, and an absorbent body disposed between the top sheet and the back sheet,
The absorbent article formed by arranging the laminated nonwoven fabric according to any one of claims 1 to 6 on the top sheet.