JP6382709B2 - Nonwoven fabric, surface sheet of absorbent article using the same, absorbent article using the same, and method for producing the same - Google Patents

Description

  The present invention relates to a nonwoven fabric. Moreover, this invention relates to the surface sheet and absorbent article of an absorbent article using this nonwoven fabric. Furthermore, this invention relates to the manufacturing method of this nonwoven fabric.

  Nonwoven fabrics are often used as the surface sheets of various absorbent articles such as disposable diapers and sanitary napkins. In order to maintain or improve the feel to the skin when the surface sheet in the absorbent article in a worn state comes into contact with a predetermined liquid such as excrement, a nonwoven fabric having an uneven shape on the surface is preferably used. ing. However, since such a nonwoven fabric has a plurality of fiber layers laminated at the time of forming irregularities during the production of the nonwoven fabric, and each fiber layer is integrated by thermal fusion, a plurality of thermal fusions resulting from that are made. There is a problem that the fiber density of the region increases, and further, the region becomes a film. In particular, when a film is formed, a predetermined liquid such as excrement is not easily transmitted downward.

  As methods for solving the above-described problems, Patent Documents 1 and 2 propose a method of forming a recess by spraying a fluid made of gas onto a single-layer or multilayer fiber web and moving the fiber.

JP 2008-25080 A JP 2008-25081 A

  However, in the methods described in Patent Documents 1 and 2, the fiber density in the recesses is lowered due to the blowing of fluid. As a result, the strength as a nonwoven fabric is reduced, and when the nonwoven fabric is used as a surface sheet of an absorbent article, rubbing between the surface sheet and the wearer's skin, etc., resulting in wear of the article There was a problem that the surface sheet was easily broken in the state. Further, in recent years, absorbent articles tend to be thinned. However, uneven nonwoven fabrics having a good touch tend to be thicker, and there is a problem that the article goes against the thinning of articles.

  Therefore, the subject of this invention is providing the nonwoven fabric which can eliminate the fault which the prior art mentioned above has, the surface sheet of an absorbent article, an absorbent article, and the manufacturing method of this nonwoven fabric.

The present invention includes a first layer having a first surface and a second surface located on the opposite side, and including a heat-fusible fiber;
A non-woven fabric having a first surface and a second surface located opposite to the first surface, and a second layer laminated on the first layer and including a heat-fusible fiber,
The second layer is laminated on the first layer with the first surface facing the second surface of the first layer,
The first layer and the second layer are joined by fusing the heat-fusible fiber contained in the first layer and the heat-fusible fiber contained in the second layer at the interface between the two layers. Has been
On the second surface of the first layer, the second layer is formed in multiple stripes so as to continuously extend in one direction in a line shape,
The first surface of the first layer has a flat shape,
The second surface of the second layer has a shape in which the cross section in the thickness direction along the direction perpendicular to the direction in which the second layer extends draws a convex curve, whereby the nonwoven fabric has the shape of the second layer. On the second surface side, it has alternating ridges composed of the second layer and ridges with the second surface of the first layer exposed between adjacent ridges as the bottom,
A nonwoven fabric having a boundary between the first layer and the second layer is provided.

  The present invention also provides a top sheet positioned on the side close to the wearer's skin when worn, a back sheet positioned on the side far from the wearer's skin when worn, and a liquid-retaining absorbent disposed between both sheets. The surface sheet of the absorbent article comprising the above-mentioned nonwoven fabric is provided with the surface sheet of the absorbent article.

Furthermore, the present invention provides a top sheet located on the side closer to the wearer's skin when worn, a back sheet located on the side far from the wearer's skin when worn, and a liquid-retaining absorber disposed between both sheets. An absorbent article comprising:
An absorbent article is provided in which the above-mentioned nonwoven fabric is used as the surface sheet, and the second layer of the nonwoven fabric is disposed so as to face the wearer's skin.

Furthermore, the present invention provides a suitable method for producing the nonwoven fabric as described above.
Step I of obtaining a laminate by placing a card web containing heat-fusible fibers on a nonwoven fabric including heat-fusible fibers;
A plurality of strips of gas are sprayed from the web side of the laminate to further separate the constituent fibers of the web, thereby exposing the surface of the nonwoven fabric raw material, and removing wrinkles from the separated web Forming step II; and
Step III of blowing hot air to the laminate to fuse the heat-fusible fiber,
The manufacturing method of the nonwoven fabric which comprises this is provided.

  The nonwoven fabric of the present invention has sufficient strength while having an uneven structure on one surface. When the nonwoven fabric of the present invention is used as a top sheet of an absorbent article, the absorbent article has good liquid permeability in the top sheet, and the absorbent performance of the article is good.

FIG. 1 is a perspective view showing a main part of one embodiment of the nonwoven fabric of the present invention. 2 is a cross-sectional view taken along line II-II in FIG. FIG. 3 is a cross-sectional view taken along line II-II showing a liquid permeation mechanism in the nonwoven fabric shown in FIG. FIG. 4 is a schematic view showing an apparatus suitably used for manufacturing the nonwoven fabric of the embodiment shown in FIG. 5 (a) to 5 (c) are schematic views sequentially showing steps for producing a nonwoven fabric using the apparatus shown in FIG. FIG. 6 is a schematic view showing another apparatus suitably used for manufacturing the nonwoven fabric of the embodiment shown in FIG. FIG. 7: is a top view which shows the principal part of another embodiment of the nonwoven fabric of this invention. 8 is a cross-sectional view of the nonwoven fabric produced in Comparative Example 1 along the width direction.

  The present invention will be described below based on preferred embodiments with reference to the drawings. The perspective view of the principal part of one Embodiment of the nonwoven fabric of this invention is shown by FIG. 2 is a cross-sectional view taken along line II-II in FIG. The nonwoven fabric 10 has the longitudinal direction X and the width direction Y orthogonal to this. The nonwoven fabric 10 has a multilayer structure including a first layer 11 and a second layer 12. The first layer 11 and the second layer 12 are in direct contact with each other, and no other layer is interposed between the two layers. The first layer 11 is a fiber layer containing heat-fusible fibers. The second layer 12 is a fiber layer containing a heat-fusible fiber, and the heat-fusible fiber may be the same as or different from the heat-fusible fiber contained in the first layer 11. Good.

  The first layer 11 has a first surface 111 and a second surface 112 located on the opposite side. The second layer 12 has a first surface 121 and a second surface 122 located on the opposite side. Then, the second layer first surface 121 is directly opposed to the first layer second surface 112, and the second layer 12 is laminated on the first layer 11. There is no other layer outside the first layer first surface 111, and the first layer first surface 111 forms one outer surface of the nonwoven fabric 10. The first layer first surface 111 has a flat shape over the entire region. On the other hand, no other layer exists outside the second layer 12 on the second layer second surface 122 side of the nonwoven fabric 10.

  The first layer 11 and the second layer 12 are joined and integrated at the interface between the both layers 11 and 12. The joining of the both layers 11 and 12 is achieved by fusing the heat-fusible fiber contained in the first layer 11 and the heat-fusible fiber contained in the second layer 12.

  As shown in FIGS. 1 and 2, the second layer 12 is spaced in the width direction Y so as to extend in one direction, that is, in the longitudinal direction X, on the first layer second surface 112. It is formed in multiple lines. The second layer 12 extends continuously along the longitudinal direction X. The term “continuously extending” means that when the second layer 12 is viewed over the entire area of the nonwoven fabric 10 in the longitudinal direction X, there is no part to be divided. However, if there are a very small number of divided portions that can be considered to be substantially continuous, it is included in the state of “continuously extending”.

  The width of the second layer 12 extending along the longitudinal direction X is substantially the same at an arbitrary position in the longitudinal direction X. However, this does not require that the width of the second layer 12 at an arbitrary position in the longitudinal direction X is substantially the same, and the width of the second layer 12 is arbitrary in the longitudinal direction X. It is not impeded to be different in the position. For example, when the second layer 12 is viewed along the longitudinal direction X, the second layer 12 has a maximum width portion and a minimum width portion, and the width gradually decreases from the maximum width portion toward the minimum width portion. The width of the second layer 12 may be changed so that the width gradually increases from the small width portion toward the maximum width portion.

  The widths of the second layers 12 are almost the same. However, depending on the specific use of the nonwoven fabric 10, the width of each second layer 12 may be varied.

  As shown in FIGS. 1 and 2, the second layer 12 extends linearly along the longitudinal direction X. The second layers 12 extend in parallel with each other, and the adjacent second layers 12 do not intersect each other over the entire area in the longitudinal direction X of the nonwoven fabric 10.

  In the nonwoven fabric 10, the first layer second surface 112 is exposed outwardly between the adjacent second layers 12 on the second layer second surface 122 side. The first layer second surface 112 exposed between the adjacent second layers 12 has a substantially flat shape and is substantially parallel to the first layer first surface. The exposed first layer second surface 112 extends continuously in the same direction as the direction in which the second layer 12 extends in a streak shape. The term “continuously extending” means that there is no parting portion when the exposed first layer second surface 112 is seen over the entire area in the longitudinal direction X of the nonwoven fabric 10. However, if there are a very small number of divided portions that can be considered to be substantially continuous, it is included in the state of “continuously extending”.

  The width of the first layer second surface 112 exposed on the second layer second surface 122 side is substantially the same at an arbitrary position in the longitudinal direction X. However, this does not require that the exposed first-layer second surface 112 is substantially the same at any position in the longitudinal direction X. The exposed first-layer second surface is not necessarily required. It is not prevented that the width of 112 is different at an arbitrary position in the longitudinal direction X. For example, when the exposed first layer second surface 112 is viewed along the longitudinal direction X, the exposed first layer second surface 112 has a maximum width portion and a minimum width portion, and the maximum width portion to the minimum width portion. The width of the exposed first layer second surface 112 may change so that the width gradually decreases toward the maximum width and further increases gradually from the minimum width portion toward the maximum width portion.

  In addition, each width of the exposed first layer second surface 112 is substantially the same. However, depending on the specific application of the nonwoven fabric 10, the widths of the exposed first layer second surface 112 may be varied.

  As shown in FIGS. 1 and 2, the exposed first layer second surface 112 extends linearly along the longitudinal direction X. Each of the exposed first layer second surfaces 112 extends in parallel with each other and does not cross over the entire area in the longitudinal direction X of the nonwoven fabric 10.

  When the cross section in the thickness direction Z along the width direction Y is viewed from the direction perpendicular to the longitudinal direction X, which is the direction in which the second layer 12 extends, the second layer second surface 122 is It has a smooth mountain shape that draws a convex curve toward the second layer 12. That is, the second layer 12 protrudes from the reference surface in the thickness direction Z using the exposed first layer second surface 112 as a reference surface. As a result, the nonwoven fabric 10 has, on the second layer second surface 122 side, the first layer second surface 112 exposed between the protruding ridges 20 formed of the second layer 12 and the adjacent protruding ridges 20 at the bottom. The concave strips 21 are alternately arranged along the width direction Y.

  As described above, the nonwoven fabric 10 of the present embodiment has a concavo-convex structure formed by alternately arranging the ridges 20 and the ridges 21 on one surface thereof, and thus in the thickness direction Z. A feeling of cushioning along the surface is produced, thereby improving the touch. Moreover, since the concave stripe part 21 located between the convex stripe parts 20 is comprised from a part of 1st layer 11 which exists over the whole area of the plane direction of the nonwoven fabric 10, it has sufficient high intensity | strength. Yes. That is, as will be described later, the first layer 11 is composed of a non-woven fabric that has been heat-sealed in advance before being laminated with a web or the like that will become the second layer 12. Therefore, between the first layer 11 and the second layer 12, although the heat-fusible fibers are fused, the nonwoven fabric 10 has a boundary. And the thickness of the 1st layer 11 is equal in the convex strip part and the concave strip part of the nonwoven fabric 10. FIG. Therefore, the nonwoven fabric of this embodiment is used suitably as a member which touches skin directly, for example, a surface sheet etc. of an absorbent article. The boundary between the first layer 11 and the second layer 12 can be confirmed, for example, by observing a cross section in the thickness direction of the nonwoven fabric 10 with a microscope.

  When the cross section in the thickness direction Z along the width direction Y is seen, the second layer 12 has a central area 12c in the width direction Y and a pair of positions located outward of the central area 12c in the width direction Y. It has side areas 12s and 12a. The central region 12c can be defined as a region having a length of 1/3 of the center when the length of the second layer 12 along the width direction Y is equally divided. The side region 12s can be defined as a region having a length of 1/3 left and right when the length of the second layer 12 along the width direction Y is divided into three equal parts. Both end points when dividing into three equal parts are positions where the second layer 12 begins to protrude from the first layer second surface 112 having a flat shape. When the fiber density of the constituent fibers of the second layer 12 is compared between the central region 12c and the side region 12s, it is preferable that the side region 12s has a higher fiber density than the central region 12c. The fiber density is the number of fibers per unit cross-sectional area. High fiber density means that the number of fibers existing per unit cross-sectional area is large and the distance between fibers is small. Low fiber density means that the number of fibers present per unit cross-sectional area is small and the distance between fibers is large. Therefore, the part where the fiber density is high has a high capillary force, and the part where the fiber density is low has a low capillary force.

  Since the fiber density is different between the central region 12c and the side region 12s, as shown in FIG. 3, the nonwoven fabric 10 is used as, for example, a surface sheet of an absorbent article, and the second layer 12 in the nonwoven fabric 10 is used as the skin of the wearer. When arranged so as to face each other, when the liquid L is excreted in the second layer 12 that is the ridge portion 20, the liquid L is discharged from the central region 12c having a low fiber density and a sparse structure. Shift to the side region 12s having a high and dense structure. The liquid L is easily drawn from the side region 12s to the first layer 11 located below the side region 12s. As a result, the absorbent article has a high liquid permeability and can also reduce the amount of liquid remaining at the ridges 20 to improve the absorption performance. In order to make the fiber density different between the central region 12c and the side region 12s, for example, the nonwoven fabric 10 may be manufactured by a method described later.

  From the viewpoint of smoothly transferring the liquid L from the central region 12c toward the side region 12s, the fiber density of the side region 12s is 150% or more, particularly 200% or more with respect to the fiber density of the central region 12c. It is preferably 1000% or less, particularly preferably 800% or less. Specifically, the fiber density of the side region 12s is preferably 150% or more and 1000% or less, and more preferably 200% or more and 800% or less with respect to the fiber density of the central region 12c.

The value of the fiber density itself of the central region 12c provides 30 / mm ³ or more, preferably particularly 50 present / mm ³ or more, 250 lines / mm ³ or less, it is preferable in particular 200 present / mm ³ or less . Specifically, it is preferable that the fiber density of the central region 12c is 30 lines / mm ³ or more 250 lines / mm ³ or less, further preferably 50 present / mm ³ to 200 present / mm ³ or less.

On the other hand, the value of the fiber density itself of the side region 12s is preferably 45 pieces / mm ³ or more, particularly preferably 60 pieces / mm ³ or more, provided that the fiber density of the central region 12c is larger than 500 pieces. / Mm ³ or less, particularly preferably 480 pieces / mm ³ or less. Specifically, the fiber density of the side region 12s is preferably 45 / mm ³ or more and 500 / mm ³ or less, more preferably 60 / mm ³ or more and 480 / mm ³ or less. The fiber density in the two side regions 12s may be the same or different.

The fiber density in the central region 12c and the side region 12s is measured by the following method. The nonwoven fabric 10 is cut in a direction orthogonal to the streak of the concavo-convex structure when viewed from the plane direction, and a fiber density measurement sample is produced. The cutting is performed using a feather shaving blade (product number FAS-10) manufactured by Feather Safety Shaving Corporation. At this time, the nonwoven fabric 10 is immersed in liquid nitrogen for 5 minutes, and then the feather razor is directed in the orthogonal direction of the nonwoven fabric 10 and the upper part of the feather razor is cut with a hammer. The central region 12c and the side region 12s in the cross section of the obtained measurement sample are enlarged and observed using a scanning electron microscope, and the cross-sectional area of the fibers cut by the cut surface per certain area is measured. . In addition, for the measurement of the cross section of the obtained sample for measurement, a scanning electron microscope JCM-5100 manufactured by JEOL Ltd. was used, and the number of fibers in the fiber cross section was about 30 to 60 when magnified. The magnification is adjusted so that the magnification is observable (100 to 500 times). Next, the measured number of cross-sections is converted into the number of cross-sections of fibers per 1 mm ² , which 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.

  From the viewpoint of further enhancing the drawability of the liquid L from the second layer 12 toward the first layer 11, it is advantageous that the first layer 11 has a higher hydrophilicity than the second layer 12. . The hydrophilicity of the 1st layer 11 and the 2nd layer 12 can be evaluated by the contact angle with respect to the water of the fiber which comprises those layers. The smaller the value of the contact angle, the higher the hydrophilicity. In order to increase the hydrophilicity of the first layer 11 compared to the second layer 12, for example, a hydrophilic agent having a degree of hydrophilicity greater than that of the second layer 12 is applied to the constituent fibers of the first layer 11, or vice versa. In addition, the hydrophilicity of the constituent fibers of the second layer 12 may be made lower than that of the first layer 11. The contact angles of the constituent fibers of the first layer 11 and the second layer 12 are measured as follows.

  As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Distilled water is used for contact angle measurement. The amount of liquid discharged from an ink jet type water droplet discharge part (manufactured by Cluster Technology Co., Ltd., pulse injector CTC-25 having a discharge part pore diameter of 25 μm) is set to 20 picoliters, and a water drop is dropped directly above the fiber. 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 video, the first image of water droplets on the fiber is attached to the attached software FAMAS (software version is 2.6.2, analysis method is droplet method, analysis method is θ / 2 method, image processing algorithm Is non-reflective, the image processing image mode is frame, the threshold level is 200, and the curvature is not corrected). Image analysis is performed to calculate the angle between the surface of the water droplet that touches the air and the fiber, and the contact angle And In addition, the sample for measurement (fiber obtained by taking out from the nonwoven fabric) is collected from the first layer 11 and the second layer 12 with a fiber length of 1 mm, and the fiber is placed on the sample table of the contact angle meter and kept horizontal. The contact angle is measured at two different positions for each fiber. In each of the above-mentioned parts, N = 5 contact angles are measured to one decimal place, and a total of 10 measured values (rounded to the second decimal place) is calculated as the contact angle at each part. Define.

  From the viewpoint of smoothly transferring the liquid L from the second layer 11 toward the first layer 11, the contact angle of the first layer 11 is 73% or more, particularly 75% or more with respect to the contact angle of the second layer 12. It is preferably 97% or less, particularly preferably 95% or less. Specifically, the contact angle of the first layer 11 with respect to the contact angle of the second layer 12 is preferably 73% or more and 97% or less, and more preferably 75% or more and 95% or less.

  The value of the contact angle itself of the first layer 11 is preferably 50 degrees or more, particularly 55 degrees or more, preferably 85 degrees or less, particularly preferably 80 degrees or less. Specifically, the contact angle of the first layer 11 is preferably 50 degrees or greater and 85 degrees or less, and more preferably 55 degrees or greater and 80 degrees or less.

  On the other hand, on the condition that the contact angle itself of the second layer 12 is larger than the contact angle of the first layer 11, it is preferably 55 degrees or more, particularly preferably 60 degrees or more, and 95 degrees or less, particularly 90 degrees. The following is preferable. Specifically, the contact angle of the second layer 12 is preferably 55 degrees or more and 95 degrees or less, and more preferably 69 degrees or more and 90 degrees or less.

  From the viewpoint of further enhancing the drawability of the liquid L from the second layer 12 toward the first layer 11, the first layer 11 and the second layer 12 are the top region of the second layer 12 and the bottom portion of the second layer 12. It is preferable that the hydrophilicity increases in the order of the region and the first layer 11. Since the order of the hydrophilicity of these parts is as described above, the gradient of hydrophilicity is more clearly formed, the liquid permeability is further improved, and the surface of the nonwoven fabric 10 on the second layer 12 side is further improved. The remaining amount of liquid is further reduced. The top region of the second layer 12 is a region on the upper side when the second layer 12 is divided into two equal parts in the thickness direction, and is a region including the top of the ridge 20. The bottom region of the second layer 12 is a lower region when the second layer 12 is divided into two equal parts in the thickness direction, and is a region in contact with the first layer 11.

  From the viewpoint of further enhancing the drawability of the liquid L from the second layer 12 toward the first layer 11, the fineness of the heat-fusible fiber contained in the second layer 12 is the heat fusion contained in the first layer 11. It is preferable that it is larger than the fineness of the adhesive fiber. By doing so, a coarse and dense gradient is formed in the fiber density between the first layer 11 and the second layer 12, so that the liquid L is further drawn from the second layer 12 toward the first layer 11. The liquid permeability of the absorbent article is improved, and the remaining amount of liquid on the second layer 12 side of the nonwoven fabric 10 is reduced, and the absorbent performance of the absorbent article is further improved.

  From the viewpoint of smoothly transferring the liquid L from the second layer 11 toward the first layer 11, the fineness of the heat-fusible fiber contained in the first layer 11 is the heat-fusibility contained in the second layer 12. It is preferably 12.5% or more, particularly 30% or more, preferably 100% or less, particularly preferably 80% or less, based on the fineness of the fiber. Specifically, the fineness of the heat-fusible fiber contained in the first layer 11 is 12.5% or more and 100% or less with respect to the fineness of the heat-fusible fiber contained in the second layer 12. It is more preferable that it is 30% or more and 80% or less.

  The value of the fineness itself of the heat-fusible fiber contained in the first layer 11 is preferably 1 dtex or more, particularly 2 dtex or more, and preferably 4 dtex or less, particularly 3.5 dtex or less. Specifically, the fineness of the heat-fusible fiber contained in the first layer 11 is preferably 1 dtex or more and 4 dtex or less, and more preferably 2 dtex or more and 3.5 dtex or less.

  On the other hand, the value of the fineness of the heat-fusible fiber contained in the second layer 12 is 3 dtex or more, especially 3.2 dtex, provided that the fineness of the heat-fusible fiber contained in the first layer 11 is larger. Preferably, it is 8 dtex or less, particularly 6 dtex or less. Specifically, the fineness of the heat-fusible fiber contained in the second layer 12 is preferably 3 dtex or more and 8 dtex or less, and more preferably 3.2 dtex or more and 6 dtex or less.

  From the viewpoint of further enhancing the drawability of the liquid L from the second layer 12 toward the first layer 11, it is preferable that the second layer 12 contains thermally stretchable fibers. A heat-extensible fiber is a fiber whose length is increased by application of heat. When such a fiber is used as a raw material fiber of the first layer 11 and the nonwoven fabric 10 is manufactured by a method described later, the heat-extensible fiber is extended during the manufacturing process, and the length thereof is increased. As a result, in the second layer 12, the distance between the fibers increases, and a coarse / dense gradient is formed between the first layer 11 and the second layer 12, so that the second layer 12 is directed to the first layer 11. As a result, the liquid L is more easily drawn. In the second layer, the heat-extensible fiber after stretching may be in a state where it does not extend even when heat is applied any more, or may be in a state where it is stretched again by application of heat. The heat-extensible fiber may be contained in the second layer separately from the heat-fusible fiber, or the heat-fusible fiber may also serve as the heat-extensible fiber. For example, a heat-extensible fiber made of a core-sheath type composite fiber having heat-fusibility is known. Examples of such fibers include Japanese Patent No. 4131852, Japanese Patent Application Laid-Open No. 2005-350836, Japanese Patent Application Laid-Open No. 2007-303035, Japanese Patent Application Laid-Open No. 2007-204899, Japanese Patent Application Laid-Open No. 2007-204901, and Japanese Patent Application Laid-Open No. 2007-2007. The fiber described in 204902 etc. can be used.

  As the heat-fusible fiber contained in the first layer 11 and the second layer 12, for example, a core-sheath type bicomponent composite fiber or a side-by-side type bicomponent composite fiber can be used. Such composite fibers are well known in the art. In addition to the heat-fusible fiber, the first layer 11 and the second layer 12 may contain a fiber having no heat-fusible property as necessary. Examples of such fibers include polyolefin fibers such as polyethylene (PE) fibers and polypropylene (PP) fibers, and composite fibers of fibers using a thermoplastic resin such as polyethylene terephthalate (PET) and polyamide. For example, the sheath component is polyethylene. Alternatively, a core-sheath fiber that is a low-melting-point polypropylene is preferable, and typical examples of the core / sheath fiber include PET (core) and PE (sheath), PP (core) and PE (sheath), and PP. (Core) and fibers having a core-sheath structure such as low melting point PP (sheath). More specifically, it is preferable to include polyolefin fibers such as polyethylene fibers and polypropylene fibers, polyethylene composite fibers, and polypropylene composite fibers. Here, the composite composition of the polyethylene composite fiber is polyethylene terephthalate and polyethylene, and the composite composition of the polypropylene composite fiber is preferably polyethylene terephthalate and low-melting polypropylene, and more specifically, PET (core) And PE (sheath), PET (core), and low melting point PP (sheath).

The basis weight of the first layer 11 is preferably 10 g / m ² or more, particularly preferably 15 g / m ² or more, and is preferably 50 g / m ² or less, particularly preferably 40 g / m ² or less. Specifically, it is preferably 10 g / m ² or more and 50 g / m ² or less, particularly preferably 15 g / m ² or more and 40 g / m ² or less. By setting the basis weight of the first layer 11 within this range, a sufficiently high strength can be imparted to the first layer 11 and the strength of the nonwoven fabric 10 can be increased. On the other hand, the basis weight of the second layer 12 is preferably 5 g / m ² or more, particularly preferably 10 g / m ² or more, more preferably 50 g / m ² or less, and particularly preferably 40 g / m ² or less. Specifically, it is preferably 5 g / m ² or more and 50 g / m ² or less, particularly preferably 10 g / m ² or more and 40 g / m ² or less. By setting the basis weight of the second layer 12 within this range, a sufficiently high cushioning property can be imparted to the second layer 12, and the touch of the nonwoven fabric 10 can be enhanced.

The total basis weight of the nonwoven fabric 10 is preferably 15 g / m ² or more, particularly preferably 18 g / m ² or more, more preferably 100 g / m ² or less, and particularly preferably 80 g / m ² or less. Specifically, it is preferably 15 g / m ² or more and 100 g / m ² or less, and particularly preferably 18 g / m ² or more and 80 g / m ² or less. By setting the basis weight of the nonwoven fabric 10 within this range, the nonwoven fabric 10 has a balance between the touch and the strength.

  When the nonwoven fabric 10 is viewed from the surface on the second layer 12 side, the ratio of the area occupied by the second layer 12 to the area of the nonwoven fabric 10 is preferably 20% or more, particularly preferably 30% or more, and 90% or less. In particular, it is preferably 80% or less. Specifically, the ratio of the area occupied by the second layer 12 to the area of the nonwoven fabric 10 is preferably 20% or more and 90% or less, and particularly preferably 30% or more and 80% or less. On the other hand, the ratio of the area occupied by the exposed first layer second surface 112 to the area of the nonwoven fabric 10 is preferably 10% or more, particularly preferably 20% or more, and is 80% or less, particularly 70% or less. It is preferable. Specifically, the ratio of the area occupied by the exposed first layer second surface 112 with respect to the area of the nonwoven fabric 10 is preferably 10% or more and 80% or less, and particularly preferably 20% or more and 70% or less. By setting the ratio of the area occupied by the second layer 12 and the ratio of the area occupied by the exposed first layer second surface 112 within this range, the nonwoven fabric 10 has a balance between the touch and the strength.

  When the nonwoven fabric 10 is viewed from the surface on the second layer 12 side, the width of the second layer 12, that is, the length along the width direction Y is preferably 3 mm or more, particularly 5 mm or more, and 20 mm or less, particularly 15 mm. The following is preferable. Specifically, the width of the second layer 12 is preferably 3 mm or more and 20 mm or less, and particularly preferably 5 mm or more and 15 mm or less. On the other hand, the width of the exposed first layer second surface 112 is preferably 3 mm or more, particularly 5 mm or more, and preferably 20 mm or less, particularly 15 mm or less. Specifically, the width of the exposed first layer second surface 112 is preferably 3 mm to 20 mm, and particularly preferably 5 mm to 15 mm. By setting the width of the second layer 12 and the exposed first layer second surface 112 within this range, the nonwoven fabric 10 has a balance between the touch and the strength. In this case, the width of the second layer 12 and the width of the exposed first layer second surface 112 may be the same or different. The width of the second layer 12 refers to the length between two end points at which the second layer 12 begins to protrude from the first layer second surface 112 having a flat shape.

  In the nonwoven fabric 10, when the first layer second surface 112 is used as a reference surface, the thickness of the second layer 12 is preferably 0.2 mm or more, particularly 0.5 mm or more, preferably 5 mm or less, particularly 3 mm or less. It is preferable that Specifically, the thickness of the second layer 12 is preferably 0.2 mm or more and 5 mm or less, and particularly preferably 0.5 mm or more and 3 mm or less. On the other hand, the thickness of the first layer 11 is preferably 0.2 mm or more, particularly 0.5 mm or more, and preferably 5 mm or less, particularly 3 mm or less. Specifically, the thickness of the first layer 11 is preferably 0.2 mm or more and 5 mm or less, particularly 0.5 mm or more and 5 mm or less.

  The total thickness of the nonwoven fabric 10 including the first layer 11 and the second layer 12 is preferably 0.4 mm or more, particularly 1 mm or more, and preferably 10 mm or less, particularly 6 mm or less. Specifically, the thickness of the nonwoven fabric 10 is preferably 0.4 mm or more and 10 mm or less, and particularly preferably 1 mm or more and 6 mm or less. The thickness of the 1st layer 11 and the 2nd layer 12, and the thickness of the nonwoven fabric 10 use the microscope (product number VH-8000) by Keyence Corporation under the state which applied the load of 49 Pa to the nonwoven fabric 10, The cross section of the nonwoven fabric 10 Is magnified by 50 to 200 times and measured. The thickness of the top part is measured at one point for each protruding line part 20, and the average value of the five points measured for each of the five protruding line parts 20 is taken as the thickness of the nonwoven fabric 10. Similarly, with respect to the thickness of the second layer, the thickness from the boundary between the first layer 11 and the second layer 12 to the top is measured per one ridge portion 20, and the average value of the five layers is determined as the second layer 12. Thickness. In the first layer 11, the groove portion 21 is measured at one point for each groove portion 21, and the average value of the five portions is defined as the thickness of the first layer 11 in the groove portion 21. Of the first layer 11, the protruding portion 20 measures the thickness from the boundary between the first layer 11 and the second layer 12 to the first layer first surface 111 for each protruding portion 20, and has five points. Let the average value be the thickness of the first layer 11 in the ridges 20. From the viewpoint of increasing the strength of the nonwoven fabric 10, the difference in the thickness of the first layer 11 in the concave stripe portion 21 and the convex stripe portion 20 is preferably 40% or less with respect to the thickness of the first layer 11 in the concave stripe portion 21, 20% or less is more preferable, and 10% or less is more preferable, and it is most preferable that the thickness of the first layer 11 in the concave portion 21 and the thickness of the first layer 11 in the convex portion 20 are equal.

  Next, the suitable manufacturing method of the nonwoven fabric 10 of this embodiment is demonstrated, referring FIG. FIG. 4 shows an apparatus 30 that is suitably used for manufacturing the nonwoven fabric 10. The manufacturing apparatus 30 includes a nonwoven fabric feeding unit 31, a web manufacturing unit 32, a gas blowing unit 33, a hot air processing unit 34, and an embossing unit 35 in this order from the upstream side to the downstream side of the manufacturing process.

  From the nonwoven fabric delivery part 31, the raw fabric nonwoven fabric 31A used as the raw material of the 1st layer 11 in the target nonwoven fabric 10 is drawn out. The web manufacturing unit 32 includes a card machine 32A. The card web 32B that is the raw material of the second layer 12 in the target nonwoven fabric 10 is manufactured by the card machine 32A. The gas blowing unit 33 includes a plurality of air nozzles 33C (see FIG. 5) arranged in a direction orthogonal to the conveyance direction A of the laminate 33A of the raw fabric nonwoven fabric 31A and the card web 32B. Air is jetted from each air nozzle 33C and blown toward the card web 32B in the laminated body 33A. In the hot air processing unit 34, hot air heated to a predetermined temperature circulates in the hood 34A, and hot air is blown onto the stacked body 33A by an air-through method. The embossing part 35 includes a pair of rolls 35A and 35B. The rolls 35A and 35B are arranged so that their rotation axes are parallel to each other and their roll peripheral surfaces are in contact with each other. At least one of the rolls 35A and 35B is an embossing roll having an uneven structure on the roll peripheral surface. The other roll is an anvil roll having a smooth roll peripheral surface, or an embossed roll having a concavo-convex structure having a complementary shape capable of meshing with the concavo-convex structure of the embossing roll. At least one of the rolls 35A and 35B may be heatable.

  In the manufacturing method of the nonwoven fabric 10 using the apparatus 30 having the above-described configuration, first, the raw fabric nonwoven fabric 31A is fed out from the nonwoven fabric feeding portion 31. The fed-out nonwoven fabric raw material is conveyed toward the conveyance direction A by the conveyor belt 31B. Various nonwoven fabrics can be used as the nonwoven fabric raw fabric 31A. Examples of the nonwoven fabric include spunbond nonwoven fabric, air-through nonwoven fabric, spunlace nonwoven fabric, meltblown nonwoven fabric, spunbond-meltblown (SM) nonwoven fabric, spunbond-meltblown-spunbond (SMS) nonwoven fabric, resin bond nonwoven fabric, and needle punch nonwoven fabric. Etc. In particular, it is preferable to use a spunbond nonwoven fabric as the nonwoven fabric raw material 31A because the first layer 11 having a spunbond layer formed from the spunbond nonwoven fabric has an advantage that the mechanical strength is increased even with a low basis weight. Further, even if a nonwoven fabric having a laminated structure of two or more layers, for example, a spunbond-meltblown (SM) nonwoven fabric or a spunbond-meltblown-spunbond (SMS) nonwoven fabric is used as the nonwoven fabric original 31A, the same advantages are obtained. Therefore, it is preferable.

  A card web 32 </ b> B manufactured by a card machine 32 </ b> A installed in the web manufacturing unit 32 is placed on the fed nonwoven fabric 31. Thereby, the stacked body 33A is obtained. This state is shown in FIG. In the laminated body 33A, the card web 32B is simply placed on the nonwoven fabric raw fabric 31A, and the constituent fibers of the card web 32B have a great degree of freedom in movement.

  Non-woven fabric 31A and card web 32B contain the same or different heat-fusible fibers. The card web 32B may include a heat-extensible fiber in addition to the heat-fusible fiber. Alternatively, a heat-fusible fiber included in the card web 32B may be one having heat extensibility.

  The stacked body 33 </ b> A is transported to the conveyor belt 33 </ b> B and transported to the gas blowing unit 33. As shown in FIG. 5B, a plurality of air nozzles 33 </ b> C are installed in the gas blowing unit 33 along the width direction of the stacked body 33 </ b> A. From each air nozzle 33C, gas, such as air, is sprayed toward the card web 32B of the laminated body 33A. In this case, since the stacked body 33A is transported in the transport direction A, the air blowing by the air nozzle 33C is performed in a plurality of lines in a streak shape. Since the constituent fibers of the card web 32B of the laminated body 33A at this stage have a large degree of freedom regarding movement as described above, the constituent fibers of the card web 32B are moved in the transport direction A by blowing air with the air nozzle 33C. They are divided according to the orthogonal direction (the direction indicated by the symbol “B” in FIG. 5B). In contrast to this, in the non-woven fabric 31A, the degree of freedom of movement of the constituent fibers is extremely low, so even if the air is blown by the air nozzle 33C, the fibers are not further divided. As a result, as shown in FIG.5 (c), while the surface of 31 A of nonwoven fabric raw materials is exposed in the blowing surface side of air, the collar 32C is formed from the card web 32B divided more.

  In the ridge 32C generated by dividing the fibers by blowing air, the side region located outside the central region 321C in the width direction rather than the central region 321C in the width direction (that is, the direction orthogonal to the conveying direction A). 322C has a relatively large amount of fibers. As a result, in the second layer 12 generated from the ridge 32C, the fiber density is higher in the side region 12s than in the central region 12c as described above.

  In addition, as described above, in the nonwoven fabric original 31A, even if air is blown by the air nozzle 33C, the fibers are not separated, so the fiber density of the nonwoven fabric original 31A changes before and after the air is blown. Does not occur. Therefore, the concave strip portion 21 formed from the nonwoven fabric raw fabric 31A does not have a low fiber density. In contrast to this, in the technique described in Patent Document 2 described in the background art section above, the fiber in both the upper layer and the lower layer in the portion corresponding to the concave strip portion 21 in the nonwoven fabric 10 of the present embodiment. Since further division occurs and the fiber density decreases, the strength of the resulting nonwoven fabric decreases. Moreover, due to the decrease in fiber density, an opening may occur unintentionally, and the adhesive used when assembling the absorbent article may be exposed to the skin side through the opening. This causes problems such as product manufacturing troubles and adhesion of the adhesive to the skin.

  Thus, the laminated body 33A in which the constituent fibers of the card web 32B are further separated is conveyed to the hot air processing unit. In the hot-air treatment unit 34, the hot-fusible fibers contained in the nonwoven fabric raw fabric 31A and the card web 32B are fused at the interface between the nonwoven fabric raw fabric 31A and the card web 32B by blowing hot air to the laminate 33A by the air-through method. The original fabric 31A and the card web 32B are integrated. At the same time, the heat-fusible fibers constituting the card web 32B are fused to form an air-through nonwoven fabric layer from the card web 32B.

  If it integrates with nonwoven fabric original fabric 31A and the card web 32B by the above method, embossing will be given in the embossing part 35, and both joining will be made more reliable. This embossing is particularly effective when a heat-fusible fiber that is less likely to be fused by an air-through method is used. Further, there is an advantage that the nonwoven fabric 10 can be thinned by embossing while maintaining the uneven shape of the target nonwoven fabric 10. Further, the embossing has an advantage that the second layer second surface 122 of the target nonwoven fabric 10 becomes smooth and the touch is further improved.

  In the above manufacturing method, if a fiber treatment agent whose hydrophilicity is lowered by heating is applied in advance to the constituent fibers of the card web 32B that is the raw material of the second layer 12, by hot air blowing in the hot air treatment unit 34, The hydrophilicity of the fibers present at the top of the ridge 32C that is most susceptible to heat is reduced. The degree of decrease in hydrophilicity decreases with increasing distance from the top. As a result, in the target nonwoven fabric 10, the hydrophilicity increases in the order of the top region of the second layer 12, the bottom region of the second layer 12, and the first layer 11. For the purpose of adjusting the hydrophilicity, the same fiber treating agent may be applied to the constituent fibers of the nonwoven fabric raw fabric 31A that is the raw material of the first layer 11.

  As a method for attaching the fiber treatment agent to the constituent fibers of the card web 32B, various known methods can be employed without particular limitation. For example, application by spraying, application by a slot coater, application by roll transfer, immersion in a fiber treatment agent, and the like can be mentioned. These treatments may be performed on the fibers before being made into a web or after being made into a web.

As the fiber treatment agent whose hydrophilicity is lowered by heating, it is preferable to use a fiber treatment agent containing the following components (A), (B) and (C).
(A) Polyorganosiloxane.
(B) Alkyl phosphate ester.
(C) An anionic surfactant represented by the following general formula (1).

（式中、Ｚはエステル基、アミド基、アミン基、ポリオキシアルキレン基、エーテル基若しくは二重結合を含んでいてもよい、炭素数１以上１２以下の直鎖又は分岐鎖のアルキル鎖を表し、Ｒ_１及びＲ_２はそれぞれ独立に、エステル基、アミド基、ポリオキシアルキレン基、エーテル基若しくは二重結合を含んでいてもよい、炭素数２以上１６以下の直鎖又は分岐鎖のアルキル基を表し、Ｘは―ＳＯ_３Ｍ、―ＯＳＯ_３Ｍ又は―ＣＯＯＭを表し、ＭはＨ、Ｎａ、Ｋ、Ｍｇ、Ｃａ又はアンモニウムを表す。）

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

  In addition, unless otherwise indicated, the “fiber treatment agent” used as a reference for the content of the fiber treatment agent-containing component such as the component (A), the component (B), and the component (C) is “attached to the nonwoven fabric”. It is a “fiber treatment agent”, not a fiber treatment agent before being attached to the nonwoven fabric. When the fiber treatment agent is attached to the nonwoven fabric, the fiber treatment agent is usually diluted with an appropriate solvent such as water, so the content of the fiber treatment agent-containing component, for example, the component (A) in the fiber treatment agent The content can be based on the total mass of the diluted fiber treatment agent.

  In the fiber to which the fiber treatment agent containing the three components (A) to (C) is attached, the polyorganosiloxane as the component (A) penetrates into the fiber with an anionic surfactant having an alkyl chain. Therefore, the hydrophilicity of the fiber surface is changed to a low value by heat treatment. This phenomenon occurs when the anionic surfactant is incompatible with the polysiloxane chain of the polyorganosiloxane and the alkyl chain of the anionic surfactant. It is thought to happen to do. Among them, the anionic surfactant of the component (C) represented by the general formula (1) has a bulky alkyl group and can penetrate into the inside of the fiber so as to penetrate the hydrophilic group. The presence of organosiloxane tends to facilitate penetration into the fiber interior. This permeation into the fiber is successfully performed, for example, by utilizing heat generated in an electromagnetic wave irradiation process which is one process of the manufacturing process described later. Hereinafter, each of the component (A) to the component (C) will be described.

[Component (A)]
As the polyorganosiloxane, either a linear one or a cross-linked two-dimensional or three-dimensional network structure can be used, but a substantially linear one is preferable.

  Specific examples of suitable polyorganosiloxanes as the component (A) are alkylalkoxysilanes, arylalkoxysilanes, alkylhalosiloxane polymers or cyclic siloxanes, and the alkoxy groups are typically methoxy groups. is there. As the alkyl group, an alkyl group which may have a side chain having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms, particularly 1 to 4 carbon atoms is suitable. Examples of the aryl group include a phenyl group, an alkylphenyl group, and an alkoxyphenyl group. Instead of an alkyl group or an aryl group, a cyclic hydrocarbon group such as a cyclohexyl group or a cyclopentyl group, or an aralkyl group such as a benzyl group may be used. The polyorganosiloxane is a polyorganosiloxane modified with a highly hydrophilic POE (polyoxyethylene) chain from the viewpoint of further promoting the penetration of the surfactant and increasing the contact angle of the fiber surface by heating. It is a concept that does not include.

  Preferred most typical polyorganosiloxanes are polydimethylsiloxane, polydiethylsiloxane, polydipropylsiloxane, etc., with polydimethylsiloxane being particularly preferred.

  The polyorganosiloxane preferably has a high molecular weight, and its molecular weight is specifically preferably a weight average molecular weight of 100,000 or more, more preferably 150,000 or more, still more preferably 200,000 or more, preferably 100. 10,000 or less, more preferably 800,000 or less, and still more preferably 600,000 or less. Two or more types of polyorganosiloxanes having different molecular weights may be used as the polyorganosiloxane. When two or more types of polyorganosiloxanes having different molecular weights are used, one of them has a weight average molecular weight of preferably 100,000 or more, more preferably 150,000 or more, further preferably 200,000 or more, and preferably Is not more than 1 million, more preferably not more than 800,000, still more preferably not more than 600,000. The other one has a weight average molecular weight of preferably less than 100,000, more preferably not more than 50,000, more preferably 30,000. It is 5,000 or less, more preferably 20,000 or less, preferably 2000 or more, more preferably 3000 or more, and still more preferably 5000 or more. Further, a preferable blending ratio (the former: latter) of the polyorganosiloxane having a weight average molecular weight of 100,000 or more and the polyorganosiloxane having a weight average molecular weight of less than 100,000 is a mass ratio, preferably 1:10 to 4: 1. More preferably, it is 1: 5 to 2: 1.

The weight average molecular weight of the polyorganosiloxane is measured using GPC. The measurement conditions are as follows. The calculated molecular weight is calculated with polystyrene.
Separation column: GMHHR-H + GMHHR-H (cation)
Eluent: L Farmin DM20 / CHCl ₃
Solvent flow rate: 1.0 ml / min
Separation column temperature: 40 ° C

  The content of the polyorganosiloxane in the fiber treatment agent is preferably 1% by mass or more, and more preferably 5% by mass or more from the viewpoint of increasing the change in hydrophilicity due to heat treatment. Moreover, 30 mass% or less is preferable from a viewpoint which is easy to absorb a liquid on the nonwoven fabric surface, and 20 mass% or less is still more preferable. For example, the content of the polyorganosiloxane in the fiber treatment agent is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less.

  A commercial item can also be used as polyorganosiloxane as (A) component. For example, “KF-96H-1 million Cs” manufactured by Shin-Etsu Chemical Co., Ltd., “SH200 Fluid 1000000 Cs” manufactured by Toray Dow Corning Co., Ltd., and those containing two types of polyorganosiloxane include Shin-Etsu Chemical Co., Ltd. “KM-903” manufactured by Co., Ltd. or “BY22-060” manufactured by Toray Dow Corning Co., Ltd. can be used.

[(B) component]
The component (B), an alkyl phosphate ester, is intended to improve the properties of raw cotton through the card machine and the uniformity of the web, thereby improving the productivity and reducing the quality of the nonwoven fabric. It is blended in the treatment agent. Specific examples of the alkyl phosphate used as the component (B) include those having a saturated carbon chain such as stearyl phosphate, myristyl phosphate, lauryl phosphate, palmityl phosphate, oleyl phosphate, palmitate Examples include unsaturated carbon chains such as trail phosphate esters and those having side chains in these carbon chains. More preferably, it is a completely neutralized or partially neutralized salt of a mono- or dialkyl phosphate ester having 16 to 18 carbon chains. Examples of the alkyl phosphate ester salt include alkali metals such as sodium and potassium, ammonia, and various amines. Alkyl phosphate ester can be used individually by 1 type or in mixture of 2 or more types.

  The blending ratio of the component (B) in the fiber treatment agent is preferably 5% by mass or more, more preferably 10% by mass or more from the viewpoint of card machine passability and web uniformity, and is also caused by heat treatment. From the viewpoint of preventing the fiber from being hydrophobized by the polyorganosiloxane, it is preferably 30% by mass or less, more preferably 25% by mass or less.

[Component (C)]
The component (C) is an anionic surfactant represented by the general formula (1) shown above. (C) component points out the component which does not contain the alkyl phosphate ester which is (B) component. Moreover, (C) component can be used individually by 1 type or in mixture of 2 or more types. Specific examples of the anionic surfactant used as the component (C) include polyoxyalkylene-modified polyhydric alcohol fatty acid esters such as polyoxyethylene (POE) -modified hardened castor oil.

Examples of the anionic surfactant in which X in the general formula (1) is —SO ₃ M, that is, the hydrophilic group is a sulfonic acid or a salt thereof, include a dialkylsulfonic acid or a salt thereof. Specific examples of the dialkylsulfonic acid include dioctadecylsulfosuccinic acid, didecylsulfosuccinic acid, ditridecylsulfosuccinic acid, di-2-ethylhexylsulfosuccinic acid, and the like, and dicarboxylic acids such as dialkylsulfosuccinic acid and dialkylsulfoglutaric acid are esterified to form diesters. Saturated fatty acids and unsaturated fatty acids such as compounds sulfonated at the alpha position, 2-sulfotetradecanoic acid 1-ethyl ester (or amide) sodium salt, 2-sulfohexadecanoic acid 1-ethyl ester (or amide) sodium salt Alpha sulfo fatty acid alkyl esters (or amides) sulfonated at the α-position of esters (or amides), dialkyl alkenes obtained by sulfonating internal olefins of hydrocarbon chains and unsaturated fatty acids Such as sulfonic acid can be mentioned. The number of carbon atoms in each of the two-chain alkyl groups of the dialkyl sulfonic acid is preferably 4 or more and 14 or less, particularly 6 or more and 10 or less.

  Specific examples of the anionic surfactant in which the hydrophilic group is sulfonic acid or a salt thereof include the following anionic surfactants.

Examples of the anionic surfactant in which X in the general formula (1) is —OSO ₃ M, that is, the hydrophilic group is sulfuric acid or a salt thereof, include dialkyl sulfates. Specific examples thereof include 2-ethylhexyl. Compounds having a branched chain such as sodium sulfate and sodium 2-hexyldecyl sulfate and alcohols having a branched chain such as polyoxyethylene 2-hexyldecyl sulfate and polyoxyethylene 2-hexyldecyl sulfate Or a fatty acid ester (or 12-sulfate stearic acid 1-methyl ester (or amide) 3-sulfate hexanoic acid 1-methyl ester (or amide) And compounds obtained by sulfating amides).

More specific examples of the anionic surfactant in which the hydrophilic group is sulfuric acid or a salt thereof include the following anionic surfactants.

  Examples of the anionic surfactant in which X in the general formula (1) is —COOM, that is, the hydrophilic group is a carboxylic acid or a salt thereof, include dialkylcarboxylic acids, and specific examples thereof include 11-ethoxyhepta. Hydroxy fatty acid chlorides, such as compounds in which the hydroxy moiety of hydroxy fatty acids such as decane carboxylic acid sodium salt and 2-ethoxypentacarboxylic acid sodium salt are alkoxylated and the fatty acid moiety is sodiumated, or alkoxylated to the amino group of amino acids such as sarcosine and glycine And compounds obtained by reacting carboxylic acid in the amino acid part with sodium, and compounds obtained by reacting fatty acid chloride with the amino group of arginic acid.

Specific examples of the anionic surfactant in which the hydrophilic group is a carboxylic acid or a salt thereof include the following anionic surfactants.

  A heat-fusible core-sheath composite fiber treated with a fiber treatment agent by using a fiber treatment agent in which an anionic surfactant represented by the general formula (1) and polyorganosiloxane are blended as a fiber treatment agent Becomes a fiber whose hydrophilicity tends to be lowered by application of heat. This is because polyorganosiloxane promotes the penetration of an anionic surfactant having two or more alkyl chains into the fiber, and the hydrophilicity of the fiber surface is likely to be lowered by the application of heat. This phenomenon is because the polysiloxane chain of the polyorganosiloxane and the alkyl chain of the anionic surfactant are incompatible with each other. Presumed to occur due to penetration of the active agent.

  The blending ratio of the component (C) in the fiber treatment agent is preferably 1% by mass or more, more preferably 5% by mass or more from the viewpoint of increasing the change in hydrophilicity due to heat treatment. When it becomes too high, it is preferably 20% by mass or less, more preferably 13% by mass or less, from the viewpoint of easily holding the liquid and impairing dryness. The blending ratio of the component (C) is preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 13% by mass or less.

  The content ratio (the former: latter) of the polyorganosiloxane of the component (A) and the anionic surfactant of the component (C) in the fiber treatment agent is a mass ratio, preferably 1: 3 to 4: 1. More preferably, it is 1: 2 to 3: 1. Moreover, the content ratio (the former: latter) of the polyorganosiloxane as the component (A) and the alkyl phosphate ester as the component (B) in the fiber treatment agent is a mass ratio, preferably 1: 5 to 10: 1, more preferably 1: 2 to 3: 1.

  The fiber treatment agent may contain other components in addition to the components (A) to (C) described above. As other components to be blended in addition to the components (A) to (C), anionic, cationic, zwitterionic and nonionic surfactants can be used. This can improve the hydrophilicity, durability, storage stability, friction resistance, and the like of the fiber. Examples of anionic surfactants include alkyl phosphate sodium salt, alkyl ether phosphate sodium salt, dialkyl phosphate sodium salt, dialkyl sulfosuccinate sodium salt, alkylbenzene sulfonate sodium salt, alkyl sulfonate sodium salt, alkyl sulfate sodium salt, secondary Examples include alkyl sulfate sodium salt (all alkyls preferably have 6 to 22 carbon atoms, particularly preferably 8 to 22 carbon atoms). In place of the sodium salt, other alkali metal salts such as a potassium salt such as an alkyl phosphate dipotassium salt can be used. Examples of the cationic surfactant include alkyl (or alkenyl) trimethyl ammonium halide, dialkyl (or alkenyl) dimethyl ammonium halide, alkyl (or alkenyl) pyridinium halide, and these compounds have 6 or more carbon atoms. Those having 18 or less alkyl groups or alkenyl groups are preferred. Examples of the halogen in the halide compound include chlorine and bromine.

  Examples of the zwitterionic surfactant include alkyl (C1-30) dimethylbetaine, alkyl (C1-30) amidoalkyl (C1-4) dimethylbetaine, alkyl (C1-30). ) Betaine-type zwitterionic surfactants such as dihydroxyalkyl (1-30 carbon atoms) betaine, sulfobetaine-type amphoteric surfactants, alanine [alkyl (1-30 carbon atoms) aminopropionic acid type, alkyl ( Carbon number 1-30) iminodipropionic acid type, etc.] amphoteric surfactant, glycine type [alkyl (carbon number 1-30) aminoacetic acid type, etc.] amphoteric surfactant such as stearylbetaine and other alkylbetaines Amino acid type amphoteric surfactants, alkylsulfonic acid type amphoteric surfactants such as alkyl (C1-30) taurine typeExamples of nonionic surfactants include polyhydric alcohol fatty acid esters such as glycerin fatty acid ester, poly (preferably n = 2 to 10) glycerin fatty acid ester, sorbitan fatty acid ester (all preferably 8 to 8 carbon atoms of fatty acid). 60), polyoxyalkylene (addition mole number 2-20) alkyl (carbon number 8-22) amide, polyoxyalkylene (addition mole number 2-20) alkyl (carbon number 8-22) ether, such as POE alkylamide, Examples include polyoxyalkylene (added mole number 2 to 20) modified (modified number 5 to 95) silicone, amino modified silicone and the like such as POE modified silicone and POP (polyoxypropylene) modified silicone.

  As the fiber treatment agent, a treatment agent such as an anti-sticking agent such as modified silicone may be added.

  FIG. 6 shows another form of the apparatus 30 that is suitably used for manufacturing the nonwoven fabric 10. Note that the description in detail regarding the device 30 shown in FIG. In FIG. 6, the same members as those in FIG. 4 are denoted by the same reference numerals.

  In the apparatus shown in FIG. 4 described above, a non-woven fabric original fabric 31A that has been produced in advance is fed out from the non-woven fabric feed portion 31. In the apparatus 30 shown in FIG. Is manufacturing. Specifically, the apparatus 30 includes a nonwoven fabric manufacturing apparatus 31E including a card machine 31C and a hot air processing unit 31D on the most upstream side in the manufacturing process. The card machine 31 </ b> C has the same structure as the card machine 32 </ b> A installed in the web manufacturing unit 32. The hot air processing unit 31D has the same structure as the hot air processing unit 34.

  In the apparatus 30 shown in FIG. 6, first, a card web 31F is manufactured by a card machine 31C, the card web 31F is conveyed to a hot air processing unit 31D, and hot air is blown by an air-through method, whereby a nonwoven fabric raw material 31A made of an air-through nonwoven fabric is used. Manufacturing. After that, the nonwoven fabric 10 is manufactured by the procedure similar to the procedure using the apparatus shown in FIG. In addition, in this apparatus 30, although the nonwoven fabric manufacturing apparatus 31E was an apparatus which manufactures an air through nonwoven fabric, it replaces with this and employ | adopts the apparatus which manufactures other nonwoven fabrics, such as a spun bond nonwoven fabric, as the nonwoven fabric manufacturing apparatus 31E. Also good.

  6 is not provided with the embossing portion 35 provided in the apparatus shown in FIG. However, the embossing by the embossing part 35 may be performed depending on the types of heat-fusible fibers contained in the nonwoven fabric raw fabric 31A and the heat-fusible fibers contained in the card web 32B.

  FIG. 7 shows another embodiment of the nonwoven fabric 10 manufactured by another manufacturing apparatus. The nonwoven fabric 10 of the embodiment shown in the figure has a configuration in which the ridges 20 and the ridges 21 meander along the longitudinal direction X that is the direction in which they extend. The nonwoven fabric 10 having such a configuration is advantageous in that the surface area per unit area is increased and the surface that comes into contact with the excretory liquid is increased, whereby the liquid can be easily transferred to the absorber side. In the nonwoven fabric 10 of this embodiment, the air nozzle 33C (see FIG. 5B) installed in the gas blowing unit 33 in the manufacturing apparatus 30 shown in FIGS. 4 and 6 is transported along the transport of the stacked body 33A. It can be manufactured by blowing air from the air nozzle 33C toward the laminated body 33A while swinging in a direction orthogonal to A.

  The nonwoven fabric 10 thus obtained was disposed between the front sheet positioned on the side close to the wearer's skin when worn, the back sheet positioned on the side far from the wearer's skin when worn, and both sheets. It is suitably used as the top sheet in an absorbent article comprising a liquid-retaining absorbent body. When using the nonwoven fabric 10 as a surface sheet of an absorbent article, it is preferable to arrange | position so that the 2nd layer 12 in this nonwoven fabric 10 may oppose a wearer's skin. Specific examples of the absorbent article in which the nonwoven fabric 10 is used include disposable diapers, sanitary napkins, incontinence pads, panty liners, and the like.

  Moreover, the nonwoven fabric 10 can also be used, for example as a sublayer sheet interposed between the surface sheet of an absorbent article, and an absorber other than the surface sheet of an absorbent article. In addition, it can also be used as a wipe sheet, cleaning sheet, filter, and the like.

  As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the manufacturing apparatus 30 of the embodiment shown in FIG. 4, the embossed portion 35 is installed on the most downstream side of the processing step, but the heat-fusible fiber and the card web 32B included in the nonwoven fabric raw fabric 31A. Depending on the type of the heat-fusible fiber included, the bonding strength between the nonwoven fabric raw fabric 31A and the card web 32B can be sufficiently increased without performing the embossing by the embossing portion 35.

The present invention further discloses the following non-woven fabric manufacturing method, non-woven fabric, and an absorbent article surface sheet and absorbent article using the non-woven fabric.
<1>
Step I of obtaining a laminate by placing a card web containing heat-fusible fibers on a nonwoven fabric including heat-fusible fibers;
A plurality of strips of gas are sprayed from the web side of the laminate to further separate the constituent fibers of the web, thereby exposing the surface of the nonwoven fabric raw material, and removing wrinkles from the separated web Forming step II; and
Step III of blowing hot air to the laminate to fuse the heat-fusible fiber,
The manufacturing method of the nonwoven fabric which comprises this.

<2>
The method for producing a nonwoven fabric according to <1>, wherein the heat-fusible fiber contained in the nonwoven fabric raw material and the heat-fusible fiber contained in the card web are the same or different.
<3>
Prior to Step I, the method for producing a nonwoven fabric according to <1> or <2>, further comprising a step of blowing the hot air onto the web containing the heat-fusible fiber to produce the nonwoven fabric original fabric.
<4>
The method for producing a nonwoven fabric according to <1> or <2>, wherein a nonwoven fabric including a spunbond layer is used as the nonwoven fabric raw material.
<5>
The method for producing a nonwoven fabric according to any one of <1> to <4>, further comprising a step IV of performing embossing after the step III.
<6>
The nonwoven fabric manufactured by the manufacturing method of any one of said <1> thru | or <5>.
<7>
A first layer having a first surface and a second surface located on the opposite side, and comprising a heat-fusible fiber;
A non-woven fabric having a first surface and a second surface located opposite to the first surface, and a second layer laminated on the first layer and including a heat-fusible fiber,
The second layer is laminated on the first layer with the first surface facing the second surface of the first layer,
The first layer and the second layer are joined by fusing the heat-fusible fiber contained in the first layer and the heat-fusible fiber contained in the second layer at the interface between the two layers. Has been
On the second surface of the first layer, the second layer is formed in multiple stripes so as to continuously extend in one direction in a line shape,
The first surface of the first layer has a flat shape,
The second surface of the second layer has a shape in which the cross section in the thickness direction along the direction perpendicular to the direction in which the second layer extends draws a convex curve, whereby the nonwoven fabric has the shape of the second layer. On the second surface side, it has alternating ridges composed of the second layer and ridges with the second surface of the first layer exposed between adjacent ridges as the bottom,
A nonwoven fabric having a boundary between the first layer and the second layer.
<8>
The non-woven fabric according to <6> or <7>, wherein the heat-fusible fiber contained in the first layer and the heat-fusible fiber contained in the second layer are the same or different.
<9>
The nonwoven fabric according to any one of <6> to <8>, wherein in the second layer formed in a plurality of strips, the second surface of the first layer is exposed between adjacent protruding strip portions.
<10>
40% or less is preferable with respect to the thickness of the 1st layer 11 in the groove part 21, and 20% or less is more preferable, and the difference of the thickness of the 1st layer 11 in the groove part 21 and the protruding item | line part 20 is 10%. More preferably, the nonwoven fabric according to any one of <6> to <9>, wherein the thickness of the first layer 11 in the concave stripe portion 21 and the thickness of the first layer 11 in the convex stripe portion 20 are most preferably equal. .

<11>
In the cross section in the thickness direction along the direction orthogonal to the extending direction of the second layer, the second layer has a fiber density higher in the side region than in the central region <6> to <10>. The nonwoven fabric according to any one of <1> or <1> to <5>.
<12>
The fineness of the heat-fusible fiber contained in the second layer is greater than the fineness of the heat-fusible fiber contained in the first layer, according to any one of <6> to <11>. The method for producing a nonwoven fabric according to any one of <1> to <5>.
<13>
The non-woven fabric according to any one of <6> to <12>, wherein the heat-extensible fiber that is thermally stretched is contained in the second layer, or the non-woven fabric according to any one of <1> to <5>. A method of manufacturing a woven fabric.
<14>
The non-woven fabric according to any one of <6> to <13>, wherein the hydrophilicity of the first layer is higher than that of the second layer, or any one of <1> to <5>. Manufacturing method of non-woven fabric.
<15>
The non-woven fabric according to any one of <6> to <14>, or <1>, wherein the hydrophilicity increases in the order of the top region of the second layer, the bottom region of the second layer, and the first layer. Thru | or the manufacturing method of the nonwoven fabric any one of <5>.

<16>
The method for producing the nonwoven fabric according to any one of <6> to <15>, or the nonwoven fabric according to any one of <1> to <5>, wherein the first layer includes a spunbond layer.
<17>
Each of the exposed second surfaces of the first layer extends in parallel with each other, and does not intersect over the entire longitudinal direction of the nonwoven fabric, or the nonwoven fabric according to any one of <6> to <16>, or The method for producing a nonwoven fabric according to any one of <1> to <5>.
<18>
In the second layer, the fiber density in the side region in the cross section in the thickness direction along the direction orthogonal to the direction in which the second layer extends is 150% or more, particularly 200% or more with respect to the fiber density in the central region 12c. Preferably, the nonwoven fabric according to any one of <6> to <17>, or preferably any one of <1> to <5>, preferably 1000% or less, particularly preferably 800% or less. Manufacturing method of non-woven fabric.
<19>
The contact angle of the first layer is preferably 73% or more, particularly preferably 75% or more, and preferably 97% or less, particularly preferably 95% or less with respect to the contact angle of the second layer <6> to < The manufacturing method of the nonwoven fabric any one of 18>, or the nonwoven fabric any one of said <1> thru | or <5>.
<20>
The non-woven fabric according to any one of <6> to <19>, wherein the fineness of the heat-fusible fiber contained in the second layer is larger than the fineness of the heat-fusible fiber contained in the first layer. Or the manufacturing method of the nonwoven fabric any one of said <1> thru | or <5>.

＜２５＞
（Ａ）成分のポリオルガノシロキサンが、ポリジメチルシロキサン、ポリジエチルシロキサン、ポリジプロピルシロキサン等であり、ポリジメチルシロキサンが特に好ましい前記＜２４＞に記載の不織布、又は前記＜１＞ないし＜５＞のいずれか１に記載の不織布の製造方法。 <21>
The fineness of the heat-fusible fiber contained in the first layer is 12.5% or more, particularly preferably 30% or more, preferably 100% or less, with respect to the fineness of the heat-fusible fiber contained in the second layer. The method for producing the nonwoven fabric according to any one of <6> to <20> or the nonwoven fabric according to any one of <1> to <5>, particularly preferably 80% or less.
<22>
When the nonwoven fabric is viewed from the surface on the second layer side, the ratio of the area occupied by the second layer to the nonwoven fabric area is preferably 20% or more, particularly preferably 30% or more, and preferably 90% or less, particularly 80%. The method for producing the nonwoven fabric according to any one of <6> to <21> or the nonwoven fabric according to any one of <1> to <5>, which is preferably as follows.
<23>
The ratio of the area occupied by the exposed second surface of the first layer with respect to the area of the nonwoven fabric is preferably 10% or more, particularly preferably 20% or more, and preferably 80% or less, particularly 70% or less. The method for producing the nonwoven fabric according to any one of <6> to <22> or the nonwoven fabric according to any one of <1> to <5>.
<24>
A fiber treatment agent whose hydrophilicity is lowered by heating is preliminarily applied to the constituent fibers as the raw material of the second layer,
The non-woven fabric according to any one of <6> to <23>, wherein the fiber containing the following component (A), component (B), and component (C) is used, or <1>: Thru | or the manufacturing method of the nonwoven fabric any one of <5>.
(A) Polyorganosiloxane.
(B) Alkyl phosphate ester.
(C) An anionic surfactant represented by the following general formula (1).

<25>
The polyorganosiloxane of component (A) is polydimethylsiloxane, polydiethylsiloxane, polydipropylsiloxane, etc., and polydimethylsiloxane is particularly preferred, or the nonwoven fabric according to <24> above, or <1> to <5> The manufacturing method of the nonwoven fabric of any one.

<26>
(B) Component alkyl phosphate ester having saturated carbon chain such as stearyl phosphate ester, myristyl phosphate ester, lauryl phosphate ester, palmityl phosphate ester, oleyl phosphate ester, palmitoleyl phosphate ester, etc. Of the unsaturated carbon chain and the non-woven fabric according to <24> or <25>, or the non-woven fabric according to any one of <1> to <5>. Manufacturing method.
<27>
X in the general formula (1) is -OSO ₃ M, that is, the anionic surfactant whose hydrophilic group is sulfuric acid or a salt thereof is a dialkyl sulfate ester,
The dialkyl sulfate ester is a compound obtained by sulfating alcohol having a branched chain such as 2-ethylhexyl sulfate sodium salt or 2-hexyldecyl sulfate sodium salt, polyoxyethylene sulfate 2-hexyldecyl sulfate or polyoxyethylene 2-sulfate A compound in which a POE chain is introduced between an alcohol having a branched chain such as hexyldecyl and a sulfate group, or 12-sulfate stearic acid 1-methyl ester (or amide) 3-sulfate hexanoic acid 1-methyl ester (or A non-woven fabric according to any one of <24> to <26>, or any one of <1> to <5>, which is a compound obtained by sulfating a hydroxy fatty acid ester (or amide) such as amide) The manufacturing method of the nonwoven fabric as described.
<28>
<24> to <27>, wherein the fiber treatment agent further contains anionic, cationic, zwitterionic and nonionic surfactants in addition to the components (A) to (C) described above. The nonwoven fabric according to any one of <1> or <1> to <5>.
<29>
Absorbency comprising a top sheet located on the side close to the wearer's skin when worn, a back sheet located on the side far from the wearer's skin when worn, and a liquid-retaining absorbent disposed between both sheets The top sheet of an absorbent article, wherein the top sheet of the article is made of the nonwoven fabric described in any one of the above items <6> to <28>.
<30>
Absorbency comprising a top sheet located on the side close to the wearer's skin when worn, a back sheet located on the side far from the wearer's skin when worn, and a liquid-retaining absorbent disposed between both sheets Goods,
The absorbent article which uses the nonwoven fabric of any one of said <6> thru | or <28> as said surface sheet, and has arrange | positioned so that the 2nd layer in this nonwoven fabric may face a wearer's skin.

<31>
A sublayer sheet made of the nonwoven fabric according to any one of <6> to <28>, and used by being interposed between a surface sheet of an absorbent article and an absorbent body.
<32>
A wipe sheet, cleaning sheet, or filter made of the nonwoven fabric according to any one of <6> to <28>.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples.

[Example 1]
The nonwoven fabric 10 shown in FIG.1 and FIG.2 was manufactured using the manufacturing apparatus 30 shown in FIG. The specific procedure is as follows.

(1) Manufacture of Non-woven Fabric 31A A card web is manufactured using a non-heat-extensible core-sheath composite fiber (core is polyethylene terephthalate, sheath is polyethylene, fineness 2.4 dtex), and hot air at 136 ° C. is air-through to the web. The nonwoven fabric raw material 31A which consists of an air through nonwoven fabric was manufactured by spraying by the system. The basis weight of the nonwoven fabric 31A was as shown in Table 1. Moreover, the fiber processing agent of the composition shown in Table 1 was made to adhere to the non-heat-extensible core-sheath-type composite fiber with the adhesion amount shown to the table | surface before manufacture of a card web.

(2) Manufacture of card web 32B Card web 32B was manufactured using a non-heat-extensible core-sheath composite fiber (the core was polyethylene terephthalate, the sheath was polyethylene, and the fineness was 3.3 dtex). Table 1 shows the basis weight of the card web 32B. Moreover, the fiber processing agent of the composition shown in Table 1 was made to adhere to the non-heat-extensible core-sheath-type composite fiber with the adhesion amount shown to the table | surface before manufacture of a card web.

(3) Manufacture of laminated body 33A and air blowing The card web 32B is placed on the nonwoven fabric raw material 31A obtained in (1) to manufacture the laminated body 33A, and the card web 32B in the laminated body 33A is manufactured. From the side, a plurality of air nozzles 33C were used to blow air in a striped manner and in multiple stripes. The pitch of the adjacent air nozzles 33C was set to 20 mm. The air blowing speed was 1.5 m / s. As a result, the constituent fibers of the card web 32B were further separated, thereby exposing the surface of the nonwoven fabric raw fabric 31A, and the ridges 32C were formed from the separated card webs 32B.

(4) Spraying of hot air Hot air of 130 ° C. was sprayed on the laminated body 33A by an air-through method, and the nonwoven fabric raw fabric 31A and the heel 32C were fused and integrated to obtain the target nonwoven fabric 10.

[Example 2]
In this embodiment, the card web 32B is made of a heat-extensible core-sheath type composite fiber (polypropylene core, polyethylene sheath, fineness 3.3 dtex, thermal elongation rate at 136 ° C., 7.9%) as the card web 32B. Manufactured. Except this, it carried out similarly to Example 1, and obtained the nonwoven fabric 10.

Example 3
In this example, the nonwoven fabric 10 shown in FIGS. 1 and 2 was manufactured using the manufacturing apparatus 30 shown in FIG. As the nonwoven fabric raw fabric 31A, a spunbond nonwoven fabric of polypropylene resin was used. A fiber treatment agent having the composition shown in Table 1 was adhered to the spunbonded nonwoven fabric in the amount of adhesion shown in the same table. The rolls 35A and 35B installed in the embossing part 35 were both heated to 136 ° C. Except this, it carried out similarly to Example 1, and obtained the nonwoven fabric 10.

[Comparative Example 1]
In this comparative example, the nonwoven fabric corresponding to the nonwoven fabric manufactured with the manufacturing method of patent document 2 was manufactured. The specific procedure is as follows.

(1) Manufacture of lower layer card web A lower layer card web was manufactured using a non-heat-extensible core-sheath composite fiber (the core was polyethylene terephthalate, the sheath was polyethylene, and the fineness was 2.4 dtex). The basis weight of the lower layer card web was as shown in Table 1. Moreover, the fiber processing agent of the composition shown in Table 1 was made to adhere to the non-heat-extensible core-sheath-type composite fiber with the adhesion amount shown to the table | surface before manufacture of a card web.

(2) Manufacture of upper layer card web An upper layer card web was manufactured using a non-heat-extensible core-sheath type composite fiber (the core was polyethylene terephthalate, the sheath was polyethylene, and the fineness was 3.3 dtex). The basis weight of the upper layer card web was as shown in Table 1. Moreover, the fiber processing agent of the composition shown in Table 1 was made to adhere to the non-heat-extensible core-sheath-type composite fiber with the adhesion amount shown to the table | surface before manufacture of a card web.

(3) Manufacture of laminated body and blowing of air An upper layer card web 32B is placed on the lower layer card web obtained in (1) to produce a laminated body, and from the side of the upper layer card web in this laminated body, A plurality of air nozzles 33C were used to blow air in a striped manner and in multiple stripes. The pitch of the adjacent air nozzles 33C was set to 20 mm. The air blowing speed was 1.5 m / s. Thus, the constituent fibers of the lower layer and the upper layer card web were further separated, and a ridge was formed from the separated lower layer and upper layer card web.

(4) Spraying of hot air Hot air of 130 ° C. was sprayed on the laminate by an air-through method, and the lower layer and the upper layer card web were fused and integrated to obtain the nonwoven fabric of Comparative Example 1. As shown in FIG. 8, this non-woven fabric has a two-layer structure of a first layer 11 ′ and a second layer 12 ′, and a convex strip portion 20 ′ extending in one direction and a concave strip portion 21 also extending in one direction. 'And alternately. The ridge portion 20 ′ is composed of a first layer 11 ′ and a second layer 12 ′, and similarly, the ridge portion 21 ′ is also composed of a first layer 11 ′ and a second layer 12 ′.

The detail of each component of the fiber treatment agent shown in Table 1 is as follows.
Component (A) Polydimethylsiloxane: Silicone “KM-903” made by Shin-Etsu Silicone. The composition of KM-903 is as follows. 18% by mass of polydimethylsiloxane having a weight average molecular weight of about 500,000, 42% by mass of polydimethylsiloxane having a weight average molecular weight of about 20,000, 5% by mass of a dispersant, and 35% by mass of water.
-Component (B) Alkyl phosphate dipotassium salt: neutralized potassium hydroxide of "Gripper 4131" manufactured by Kao Corporation.
-(C) component POE (addition mole number 25) modified polyhydric alcohol fatty acid ester: POE modified hardened castor oil, "Emanon CH25" manufactured by Kao Corporation.
-POE, POP modified silicone; "X-22-4515" by Shin-Etsu Chemical Co., Ltd.
POE alkylamide; “Amizole SDE” manufactured by Kawaken Fine Chemicals Co., Ltd.
Stearyl betaine: Alkyl betaine “Amphitor 86B” manufactured by Kao Corporation.

  In Table 1, the blending amount of component (A) is the blending amount of silicone alone in the composition of “KM-903” described above, and is not the blending amount of “KM-903” as a whole. That is, the blending ratio of each component of the fiber treatment agent shown in Table 1 is a value calculated by excluding the dispersant and water in KM-903.

  In Table 1, the fiber treatment agent adhesion amount was measured as follows using a quick residual oil extractor. 2 g of the fiber to be measured was measured and placed in a predetermined container with a small hole in the lower part. After that, by pressing the fiber with the lid, the fiber is pushed into the lower part of the container, and 10 cc of ethanol / methanol (1: 1) mixed solution is put into it, and after standing for 10 minutes, the lid is put on again and strongly. The ethanol / methanol component contained in the fiber was squeezed by pressing, and the liquid was put into a weighing dish. The solvent was blown off by heating the weighing pan, and the amount of the fiber treatment agent adhered was measured by measuring the weight after heating from the original weight of the weighing pan. N = 3 was measured, and the average was defined as the fiber treatment agent adhesion amount.

[Evaluation]
About the nonwoven fabric obtained by the Example and the comparative example, the contact angle of the convex part top part by the side of 2nd layer 2nd surface, the contact angle of the bottom part in the center area of the convex part by the side of 2nd layer 1st, and 1st The contact angle on the first surface side of the layer was measured by the method described above.
Moreover, the fiber density of the center area | region of a protruding item | line part and the fiber density of the side area of a protruding item | line part were measured by the above-mentioned method.
Moreover, the thickness (under 49 Pa load) of the nonwoven fabric was measured by the method described above. Each of Examples 1 to 3 had a clear boundary between the first layer and the second layer. On the other hand, the comparative example does not have a clear boundary between the first layer and the second layer, and Table 1 shows the results measured by determining the boundary.
Furthermore, the tensile strength in the width direction Y (maximum strength until breakage) was measured. For the measurement, a sample piece having a width of 5 cm was used.
Furthermore, the liquid return amount, the liquid remaining amount, and the liquid absorption time were measured by the following methods. The results are shown in Table 1.

[Liquid return amount and liquid absorption time]
As an example of the absorbent article, the surface sheet is removed from a baby diaper (Mao's Sarasara Air-Through (registered trademark) M size) as an example of an absorbent article, and a nonwoven fabric specimen (hereinafter referred to as a nonwoven fabric specimen) is used instead. An infant diaper for evaluation obtained by fixing its periphery was used. In addition, when removing a surface sheet from a diaper, the battle sheet (trademark registration) cold spray made from Nichiban Co., Ltd. was sprayed on the surface sheet, and the surface sheet was peeled off from the diaper after that. Moreover, after putting the nonwoven fabric test body on the diaper from which the topsheet was removed, the nonwoven fabric test body and the diaper were fixed by reciprocating between two pairs of rolls with an interval of 85 mm. The diaper was spread in a flat shape, an acrylic plate with a cylindrical injection portion was placed on the top sheet, a weight was placed on the acrylic plate, and a load of 2 kPa was applied to the absorber portion. The injection part provided in the acrylic plate has a cylindrical shape (height 53 mm) with an inner diameter of 36 mm. The acrylic plate has a cylindrical part of the cylindrical injection part at a third portion in the longitudinal direction and the central axis in the width direction. A through hole having an inner diameter of 36 mm is formed so that the central axes coincide with each other and communicates between the inside of the cylindrical injection portion and the surface sheet facing surface of the acrylic plate. The core wrap sheet covering the diaper absorbent core is placed so that the central axis of the cylindrical injection portion of the acrylic plate comes to a position of 155 mm from the tip of the longitudinal side of the core wrap sheet, and 40 g of artificial urine is injected. Absorbed and allowed to stand for 10 minutes, and further injected 40 g of artificial urine for absorption. Such artificial urine injection operation was repeated four times, and a total of 160 g of artificial urine was absorbed in the diaper. After standing for 10 minutes from the completion of injection, the cylinder and pressure were removed. Next, filter paper No. manufactured by Advantech Toyo Co., Ltd., centering on the injection point of artificial urine in the diaper. A load was applied so that 16 sheets of 5C (100 mm × 100 mm, mass measurement W1) were applied, and a pressure of 3.5 kPa was further applied thereon. After the elapse of 2 minutes, the load was removed, the mass (W2) of the filter paper that absorbed artificial urine was measured, and the liquid return amount was calculated according to the following equation.
Liquid return amount (g) = mass of filter paper after pressurization (W2) −mass of first filter paper (W1)

Further, in the measurement of the liquid return amount, the injection time of artificial urine at each injection time (the time from the start of injection until the entire amount was absorbed by the diaper) was defined as the liquid absorption time.
The smaller the liquid return amount, the higher the evaluation that the liquid return is less likely to occur, and the shorter the liquid absorption time, the better the excretion fluid permeability and the higher the evaluation.
The composition of the artificial urine is as follows: 1.94% by mass of urea, 0.7954% by mass of sodium chloride, 0.11058% by mass of magnesium sulfate (septahydrate), 0.06208 of calcium chloride (dihydrate) % By mass, potassium sulfate 0.19788% by mass, polyoxyethylene lauryl ether 0.0035% by mass and ion-exchanged water (remaining amount).

[Liquid remaining amount]
As an example of the absorbent article, the surface sheet is removed from a baby diaper (Mao's Sarasara Air-Through (registered trademark) M size) as an example of an absorbent article, and a nonwoven fabric specimen (hereinafter referred to as a nonwoven fabric specimen) is used instead. An infant diaper for evaluation obtained by fixing its periphery was used. In addition, when removing a surface sheet from a diaper, the battle sheet (trademark registration) cold spray made from Nichiban Co., Ltd. was sprayed on the surface sheet, and the surface sheet was peeled off from the diaper after that. Moreover, after putting the nonwoven fabric test body on the diaper from which the topsheet was removed, the nonwoven fabric test body and the diaper were fixed by reciprocating between two pairs of rolls with an interval of 85 mm. 40g of artificial urine is injected at a rate of 5g / sec using an infusion pump at a position of 155mm from the tip of the ventral portion in the longitudinal direction of the core wrap sheet covering the absorbent core of the diaper. Then, it was allowed to stand for 10 minutes, and then 40 g of artificial urine was injected and absorbed. Such artificial urine injection operation was repeated four times, and a total of 160 g of artificial urine was absorbed in the diaper. After standing for 10 minutes from the completion of the injection, the 10 cm × 10 cm surface sheet is peeled off around the injection point, and the weight (W4) is measured. Thereafter, the top sheet was dried at 105 ° C. for 1 hour using a dryer, the weight (W3) was measured, and the remaining liquid amount was calculated as in the following equation.
Liquid remaining amount (g) = 160 g of surface material after injection (W4) −mass of dried surface material (W3)

  As is clear from the results shown in Table 1, it can be seen that the nonwoven fabric obtained in each example has higher tensile strength than the nonwoven fabric of the comparative example. Moreover, the disposable diaper using the nonwoven fabric obtained in each Example as a top sheet is less liquid remaining amount and the liquid return amount than the disposable diaper using the nonwoven fabric obtained in the comparative example as a top sheet, and the liquid It can be seen that the absorption time is short.

DESCRIPTION OF SYMBOLS 10 Nonwoven fabric 11 1st layer 111 1st layer 1st surface 112 1st layer 2nd surface 12 2nd layer 12c Central region 12s Side region 121 2nd layer 1st surface 122 2nd layer 2nd surface 20 Projection part 21 Concave section

Claims (11)

A first layer having a first surface and a second surface located on the opposite side, and comprising a heat-fusible fiber;
A non-woven fabric having a first surface and a second surface located opposite to the first surface, and a second layer laminated on the first layer and including a heat-fusible fiber,
The second layer is laminated on the first layer with the first surface facing the second surface of the first layer,
The first layer and the second layer are joined by fusing the heat-fusible fiber contained in the first layer and the heat-fusible fiber contained in the second layer at the interface between the two layers. Has been
On the second surface of the first layer, the second layer is formed in multiple stripes so as to continuously extend in one direction in a line shape,
The first surface of the first layer has a flat shape,
The second surface of the second layer has a shape in which the cross section in the thickness direction along the direction perpendicular to the direction in which the second layer extends draws a convex curve, whereby the nonwoven fabric has the shape of the second layer. On the second surface side, it has alternating ridges composed of the second layer and ridges with the second surface of the first layer exposed between adjacent ridges as the bottom,
A nonwoven fabric having a boundary between the first layer and the second layer.   The nonwoven fabric according to claim 1, wherein the second layer has a fiber density higher in the side region than in the central region in a cross section in the thickness direction along a direction orthogonal to the direction in which the second layer extends.   The nonwoven fabric according to claim 1 or 2, wherein the fineness of the heat-fusible fiber contained in the second layer is larger than the fineness of the heat-fusible fiber contained in the first layer.   The nonwoven fabric as described in any one of Claim 1 thru | or 3 in which the heat | fever extensible fiber thermally expanded is contained in the 2nd layer.   The nonwoven fabric according to any one of claims 1 to 4, wherein the first layer has a higher hydrophilicity than the second layer.   The nonwoven fabric as described in any one of Claims 1 thru | or 5 with which hydrophilicity becomes high in order of the top region of a 2nd layer, the bottom region of a 2nd layer, and a 1st layer.   Absorbency comprising a top sheet located on the side close to the wearer's skin when worn, a back sheet located on the side far from the wearer's skin when worn, and a liquid-retaining absorbent disposed between both sheets A surface sheet of an absorbent article, wherein the surface sheet of the article is made of the nonwoven fabric according to any one of claims 1 to 6. Absorbency comprising a top sheet located on the side close to the wearer's skin when worn, a back sheet located on the side far from the wearer's skin when worn, and a liquid-retaining absorbent disposed between both sheets Goods,
The absorbent article which uses the nonwoven fabric as described in any one of Claims 1 thru | or 6 as said surface sheet, and has arrange | positioned so that the 2nd layer in this nonwoven fabric may face a wearer's skin. Step I of obtaining a laminate by placing a card web containing heat-fusible fibers on a nonwoven fabric including heat-fusible fibers;
A plurality of strips of gas are sprayed from the web side of the laminate to further separate the constituent fibers of the web, thereby exposing the surface of the nonwoven fabric raw material, and removing wrinkles from the separated web Forming step II; and
Step III of blowing hot air to the laminate to fuse the heat-fusible fiber,
The manufacturing method of the nonwoven fabric which comprises this.   The manufacturing method of Claim 9 which further includes the process of spraying a hot air on the web containing the said heat-fusible fiber before the process I, and manufacturing the said nonwoven fabric original fabric.   The manufacturing method of Claim 9 or 10 which further includes the process IV which performs embossing after the process III.

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