JP5925835B2 - Nonwoven manufacturing method - Google Patents

Description

The present invention relates to a method for producing a nonwoven fabric.

  In an absorbent article such as an incontinence pad, a sanitary napkin, or a disposable diaper, the excretory liquid is permeated in the thickness direction from the top sheet and held by the absorbent body. In this liquid permeation route, the top sheet is likely to be in close contact with the skin while directly receiving excretory fluid. In such a close contact state, it is indispensable to take measures against skin troubles such as rough skin, and various proposals have been made on the surface sheet from the viewpoint of a good wearing feeling.

  For example, Patent Document 1 describes a product in which a surface sheet has double-sided irregularities and a hydrophobic skin care agent is attached to both sides of a protruding portion that contacts the skin in order to enhance the skin care effect on the skin. Further, Patent Document 2 has a concavo-convex structure, and the convex part has fibers inside thereof, the top part is hydrophobic, and the part other than the top part has lower hydrophobicity than the top part. Or the fiber sheet which has hydrophilic property is described.

JP 2012-143543 A JP-T-2006-183168

In the surface sheet described in Patent Document 1, more hydrophobic skin care agent is applied to the skin contact surface side than the non-skin contact surface side to facilitate the transition to the skin. Further, the fiber sheet described in Patent Document 2 is a hydrophobic portion that comes into contact with the skin of the convex portion, and tries to suppress water retention on the surface side and liquid return from the absorber side.
On the other hand, when the convex part which touches skin is made into a hydrophobic part, there exists a problem that a fluid flow will arise easily on the surface of a surface sheet, ie, a skin contact surface. In this case, the flowing liquid may cause side leakage while contacting the skin. Such a liquid flow on the skin contact surface is not considered in the surface sheet of Patent Documents 1 and 2. And since the nonwoven fabric described in any literature also has an uneven structure, it is estimated that it has a certain amount of cushioning properties. These nonwoven fabrics are desired to be further improved in cushioning properties.

  The present invention has a high cushioning property when a nonwoven fabric is used as a top sheet of an absorbent article, and reduces the amount of liquid return in a large amount of excretion under high load and prevents leakage due to liquid flow on the surface. The present invention relates to a method for producing a compatible nonwoven fabric and a nonwoven fabric.

The present invention has a concavo-convex shape, conveys a web containing thermoplastic fibers to a heated support, and blows hot air from above the web toward the support to shape the concavo-convex shape on the web. A method for producing a nonwoven fabric, the step of heating the support to a temperature range of not less than the glass transition point of the fibers constituting the web and not more than the melting point, and the fibers of the web by the first hot air blowing The step of temporarily fusing the concavo-convex shape and the second hot air having a temperature higher than that of the first hot air is blown, and the fibers of the web are fused together while the concavo-convex shape is maintained. The manufacturing method of a nonwoven fabric provided with the process of fixing the said uneven | corrugated shape is provided .

According to the method for producing a nonwoven fabric of the present invention, it becomes easy to form, has a high cushioning property, maintains an uneven shape even under high load, and increases the contact area to the skin. Therefore, the nonwoven fabric which suppresses adhesion of the discharged liquid to skin can be manufactured .

It is the fragmentary sectional view showing one desirable embodiment of the nonwoven fabric concerning the present invention. It is the plane arrangement | positioning figure which showed the preferable example of arrangement | positioning of the 1st, 2nd protrusion part of the nonwoven fabric which concerns on this embodiment. It is principal part sectional drawing which showed an example of the ridge part of the nonwoven fabric which concerns on this embodiment. It is drawing which showed an example of the fiber orientation in the wall part of the 1st protrusion part of the nonwoven fabric which concerns on this embodiment, (a) is principal part sectional drawing, (b) is a top view. It is drawing which showed an example of the fiber orientation in the wall part of the 2nd protrusion part of the nonwoven fabric which concerns on this embodiment, (a) is principal part sectional drawing, (b) is a top view. It is principal part sectional drawing which showed an example of the dimension of each site | part of the nonwoven fabric which concerns on this embodiment. It is principal part sectional drawing which showed an example of the top space | interval of the nonwoven fabric which concerns on this embodiment. It is principal part sectional drawing which showed the preferable example of the manufacturing method of the nonwoven fabric which concerns on this invention, (a) is principal part sectional drawing which showed the state which sprayed the 1st hot air, (b) is 1st It is principal part sectional drawing which showed after blowing hot air, (c) is principal part sectional drawing which showed the state which sprayed the 2nd hot air. It is the partially cutaway perspective view which showed typically the disposable diaper as one preferable embodiment of the absorbent article using the surface sheet which concerns on this invention.

A preferred embodiment of the nonwoven fabric according to the present invention will be described below with reference to FIGS. 1 and 2.
The nonwoven fabric 10 of the present invention is preferably applied to a top sheet of absorbent articles such as sanitary napkins, disposable diapers, and incontinence pads. At that time, it is preferable to use the first surface side Z1 facing the wearer's skin surface and the second surface side Z2 arranged on the absorber (not shown) side inside the article. Hereinafter, an embodiment in which the first surface side Z1 of the nonwoven fabric 10 shown in the drawings is used toward the skin surface of the wearer will be described. The present invention is not construed as being limited thereby. In the plane arrangement diagram of FIG. 2, the upper side of the nonwoven fabric 10 is defined as the first surface side Z1 and the lower side of the nonwoven fabric 10 is defined as the second surface side Z2 in the z-axis of the orthogonal coordinate system.

As shown in FIGS. 1 and 2, the nonwoven fabric 10 of the present invention has a continuous uneven curved surface and forms a seamless sheet surface. That is, the non-woven fabric of the sheet body protrudes on the first surface side Z1 on the side in plan view and has the internal space 11K, and the internal surface protrudes on the second surface side Z2 opposite to the first surface side Z1. And a second protrusion 12 having 12K. For example, the first protrusion 11 and the second protrusion 12 are different directions that intersect in plan view over the entire surface of the nonwoven fabric 10 in the first direction X and the second direction Y, respectively, in a plane parallel to the xy plane of the orthogonal coordinate system. They are arranged alternately and continuously. In the present embodiment, the first direction X and the second direction Y are orthogonal. Accordingly, the first direction X can be a direction parallel to the x-axis of the orthogonal coordinate system, and the second direction Y can be a direction parallel to the y-axis of the orthogonal coordinate system. Note that the first direction X and the second direction Y do not have to be orthogonal to each other, and preferably cross, for example, in the range of about 60 ° to 120 °.
The convex portion viewed from the first surface side Z <b> 1 is the first projecting portion 11, and the concave portion is the second projecting portion 12. Further, the convex portion viewed from the second surface side Z <b> 2 is the second projecting portion 12, and the concave portion is the first projecting portion 11. Therefore, the first protrusion 11 and the second protrusion 12 are partially shared.

There is no clear boundary between the first projecting portion 11 and the second projecting portion 12, and in the present specification, the space that each of the first projecting portion 11 and the inner space 12K of the second projecting portion 12 has is used as a reference. Define as follows. That is, the 1st protrusion part 11 is the part protruded to the 1st surface side Z1 of the nonwoven fabric 10 of the 1st surface side Z1 which covers the internal space 11K and this. The part which protruded to the 1st surface side Z1 of the nonwoven fabric 10 is a part which connected from the 1st protrusion part top part 11T to the bottom part of the surrounding internal space 12K through the wall part 13 (14). Moreover, the 2nd protrusion part 12 containing the internal space 12K is a part which protruded to the 2nd surface side Z2 of the nonwoven fabric 10 of the 2nd surface side Z2 which covers the internal space 12K and this. The portion recessed in the second surface side Z2 of the nonwoven fabric 10 is a portion connecting the bottom portion of the internal space 12K to the surrounding first protruding portion top portion 11T through the wall portion 13 (14). The first projecting portion 11T and the second projecting portion 12 are shared between the first projecting portion top portion 11T and the bottom portion of the internal space 12K, and the wall portion divides the two inner spaces 11K and the inner space 12K. 13 (14).
Furthermore, in order to clarify the 1st protrusion part 11, the 2nd protrusion part 12, and the wall part 13, the height of the thickness direction of the nonwoven fabric 10 is divided into 3 equal parts, the upper part is the 1st protrusion part 11, and the intermediate part is a wall. The part 13 (14) and the lower part are defined as the second projecting part 12. Further, the ridge portion 15 is a portion connecting the highest positions in the first surface side Z1 direction in which the adjacent first projecting portions 11 are continuous. Furthermore, when it sees with the 1st protrusion part 11 and the ridge part 15, the lower part which equally divided the 1st protrusion part top part 11T and the lowest position of the ridge part 15 into the 1st surface side Z1 direction is made into the ridge part 15. .

  The adjacent first projecting portions 11 are continuously connected in an oblique direction with respect to the first direction X and the second direction Y via the ridge portion 15. In other words, the first projecting portion 11 is connected to the first direction X and the second direction Y in an oblique direction like a mountain range via the ridge portion 15. When the first direction X and the second direction Y are orthogonal to each other, the oblique direction is, for example, a 45 ° oblique direction with respect to each direction. Further, the adjacent second projecting portions 12 are continuous in the oblique direction with respect to the first direction X and the second direction Y through the ridge portion 15 as viewed from the second surface side Z2, similarly to the first projecting portion 11. Are connected.

  The height h1 in the thickness direction of the first protrusion 11 is higher than the height h5 in the thickness direction of the ridge portion 15 (see also FIG. 3). Each of the heights h1 and h5 represents a height in a direction perpendicular to the plane S including the apex of the second projecting portion top portion 12, and the height h1 is defined on the first surface side Z1 of the first projecting portion top portion 11T. The height h5 represents the height of the first surface side Z1 of the lowest portion of the ridge portion 15 between the first protrusions 11. Since the height h1 in the thickness direction of the first protruding portion 11 is higher than the height h5 of the ridge portion 15 in this way, the liquid is poured into the internal space 12K of the second protruding portion 12 that is surrounded on all sides by the first protruding portion 11. Accumulated, the liquid flows over the ridge 15 in the direction of the internal space 12K of the adjacent second protrusion 12. In this case, the liquid also flows below the ridge 15. However, no liquid leaks to the first surface side Z1. In addition, also in FIG. 3, the 1st surface side Z1 shows a wearer's skin surface side, and the 2nd surface side Z2 shows a non-skin surface side.

Further, on both the first surface side Z1 and the second surface side Z2, the hydrophilicity of the first protruding portion top portion 11T is lower than the portion excluding the first protruding portion top portion 11T, or the first protruding portion top portion 11T is hydrophobic. have. That is, the hydrophilicity of the first protruding portion top portion 11T is lower than that of the second protruding portion top portion 12T and the wall portion 13. In other words, the first protrusion top 11T is more hydrophobic than the second protrusion top 12T and the wall 13 (14). Thereby, when the nonwoven fabric 10 is used as a surface sheet, the remaining amount of the liquid that touches the skin is reduced on the first surface side Z1 that is the skin contact surface side. In addition, the first surface side Z1 has a smaller hydrophobic area than the second surface side Z2 of the first protrusion top portion 11T. This makes it difficult for the overflowing liquid from the absorber (not shown) to return to the first surface side Z1 under high pressure such that the wearer is sleeping. Therefore, the liquid which returns to the 1st surface side Z1 used as the skin surface side is suppressed and reduces.
The level of hydrophilicity and the level of hydrophobicity are determined by measuring the contact angle described later. The smaller the contact angle value described later, the higher the hydrophilicity, and the larger the contact angle value, the higher the hydrophobicity. In the present application, even in a region that is considered to be hydrophobic, the level of hydrophilicity is compared and judged by the magnitude of the contact angle value described later.
In addition, even if the 1st protrusion part top part 11T is not hydrophobized, the nonwoven fabric 10 has a high cushioning property, maintains an uneven | corrugated shape even under high load, and is discharged | emitted to skin The effect of the present invention that it is possible to suppress the adhesion of is obtained. As described above, it is more preferable that the first projecting portion top portion 11T is made hydrophobic because adhesion of the discharged liquid to the skin can be further suppressed.

As shown in FIG. 4, the fibers 16 constituting the wall portion 13 have fiber orientation in the direction indicated by the arrow A connecting the first protruding portion top portion 11T and the edge portion of the opening portion 11H of the internal space 11K. In other words, it has fiber orientation in the direction in which the wall portion 13 stands. Therefore, it has the radial fiber orientation which goes to the 1st protrusion part top part 11T. In addition, the direction which ties the 1st protrusion part top part 11T and the edge part of the opening part 11H of the internal space 11K, and the direction where the wall part 13 stands up substantially correspond with the thickness direction in a nonwoven fabric.
Moreover, as shown in FIG. 5, the fiber 16 which comprises the wall part 14 (13) of the 2nd protrusion part 12 is the arrow A which connects the edge part of the opening part 12H of the 2nd protrusion part top part 12T and its internal space 12K. It has fiber orientation in the direction indicated by. The fiber orientation of the wall portion 14 is the same as the fiber orientation of the wall portion 13 in the common portion with the wall portion 13 described above. Note that the direction connecting the second projecting portion top 12T and the edge of the opening 12H of the internal space 12K and the direction in which the wall 13 rises substantially coincide with the thickness direction of the nonwoven fabric.

Thus, since the wall part 13 of the 1st protrusion part 11 has fiber orientation in the direction which ties the top part 11T of the 1st protrusion part 11, and the opening part 11H of the internal space 11K of the 1st protrusion part 11, it is a wearer. Since the first protrusion 11 and the second protrusion 12 are not easily crushed even under high pressure such as sleeping, the shape retention is excellent, and the problem of stuffiness is solved with high air permeability. In addition, a firm stiffness is born in the wall portion 13 and there is a moderate cushioning property that prevents the fibers from being crushed in the thickness direction. Furthermore, even if the nonwoven fabric 10 is crushed due to the pressing force due to the fiber orientation of the wall portion 13, the shape restoring force is large, and the initial cushioning force is easily maintained even if the packing state and wearing are continued. That is, the non-woven fabric 10 is excellent in shape retention even at the seating pressure of the wearer, the skin contact area is kept small even at the time of high pressurization, and the first and second protrusions are not easily crushed and are easily recovered even if deformation occurs. .
By the fibers oriented in the thickness direction of the wall portion 13, the liquid smoothly flows through the fibers and moves to an absorbent body (not shown) disposed on the lower surface of the nonwoven fabric 10, and the fiber orientation of the wall portion 13. As a result, liquid return is reduced, and a smooth touch is realized. Moreover, it is useful for prevention of a blurring by being excellent in the air permeability of nonwoven fabric 10 itself by maintenance of the structure mentioned above.

When the nonwoven fabric 10 is pressurized at a pressure of 3.5 kPa, the height h1 in the thickness direction of the first protrusion 11 is higher than the height h5 of the ridge 15. As a result, the flow of the liquid on the first surface side Z1 of the nonwoven fabric 10 is oblique to the first direction X parallel to the x direction of the orthogonal coordinate system and the second direction Y parallel to the y direction of the orthogonal coordinate system. The liquid begins to flow. That is, when the nonwoven fabric 10 is used as the top sheet of the absorbent article and the first direction X is used as the width direction of the absorbent article, the liquid flows in an oblique direction with respect to the width direction of the absorbent article. Thereby, the liquid overflowing the internal space 12K of the second projecting portion 12 easily flows into the internal space 12K of the adjacent second projecting portion 12 through the ridge portion 15 through the ridge portion 15, Since the distance until the liquid leaks becomes longer and is easily absorbed in the meantime, the liquid is less likely to leak sideways.
The ratio (h1 / h5) between the height h1 of the first protrusion 11 in the thickness direction and the height h5 of the ridge 15 when the nonwoven fabric 10 is pressurized at a pressure of 3.5 kPa is a side leakage. From the viewpoint of difficulty, it is preferably 1.01 or more, more preferably 1.05 or more, and further preferably 1.2 or more. Moreover, as an upper limit, it is preferable that it is 2.5 or less, It is more preferable that it is 2.0 or less, It is further more preferable that it is 1.8 or less.
The reason why the nonwoven fabric 10 is measured by pressurizing at a pressure of 3.5 kPa is that it simulates the pressure applied to the nonwoven fabric when the wearer is seated. That is, the seating pressure is assumed to be 3.5 kPa. A wearer is a wearer of the baby diaper which is the main focus in this specification, that is, an infant.
Moreover, the pressure concerning a nonwoven fabric when a wearer is standing is measured as follows in the meaning which contrasts with the pressure concerning a nonwoven fabric when the wearer is sitting. When the wearer is standing, the load applied to the nonwoven fabric is basically assumed to be no load. However, when the nonwoven fabric is measured without applying a load, the measurement values vary due to the characteristics of the nonwoven fabric, which is an aggregate of fibers. For this reason, measurement is carried out by imitating measurement with substantially no pressure while suppressing variations in measured values, that is, with a load of about 0.05 kPa as a state close to no pressure.

  Further, the first protruding portion 11 is a truncated cone having a sharper rising angle of the wall portion and a rounded top portion of the hemisphere than a cone having a rounded top portion. preferable. The rising angle α of the wall portion 13 of the first projecting portion 11 is not less than 0 ° and not more than 20 °, preferably greater than 0 ° and not more than 20 °, more preferably not less than 0 ° and not more than 15 °. Is more preferable, and it is further more preferable that it is larger than 0 degree and 12 degrees or less. The rising angle α is obtained by a measurement method described later. If the rising angle α is too large, the nonwoven fabric tends to be crushed in the thickness direction, the cushioning effect decreases, and the liquid return amount increases. Furthermore, since the skin contact area at the time of high pressurization becomes large, it becomes difficult to give a wearer a gentle touch to the skin.

  In this embodiment, the 1st protrusion part 11 and the 2nd protrusion part 12 are made into the truncated cone shape or hemisphere which rounded each top part 11T and 12T. More specifically, the protruding shape of the first protruding portion 11 is a shape close to a truncated cone, while the protruding shape of the second protruding portion 12 is a cone or truncated cone shape with a rounded top. In addition, in this embodiment, the 1st, 2nd protrusion parts 11 and 12 are not limited to the said shape, What kind of protrusion form may be sufficient. For example, it is practical to have various cone shapes. In the present specification, the term “conical shape” means that a cone, a truncated cone, a pyramid, a truncated pyramid, an oblique cone, and the like are included. In this embodiment, the 1st protrusion part 11 is holding | maintaining the internal space 11K of the truncated cone shape with the roundness in the top part similar to the outer diameter. Moreover, the 2nd protrusion part 12 hold | maintains the truncated cone shape or hemispherical internal space 12K with the roundness in the top part similar to the outer diameter.

  A wall 13 is provided between the top of the first protrusion 11 (hereinafter also referred to as the first protrusion 11) 11T and the opening 11H. The wall portion 13 forms an annular structure in the first projecting portion 11. Moreover, it has the wall part 14 between the top part (henceforth the 2nd protrusion part top part) 12T of the 2nd protrusion part 12, and its opening part 12H. The wall portion 14 forms an annular structure in the second projecting portion 12. The wall portion 14 is shared with the wall portion 13 in part. The “annular” herein is not particularly limited as long as it has a series of endless shapes in plan view, and may be any shape such as a circle, an ellipse, a rectangle, or a polygon in plan view. In order to maintain the continuous state of the sheet suitably, a circle or an ellipse is preferable. Furthermore, “annular” is a three-dimensional shape: cylinder, oblique cylinder, elliptical cylinder, truncated cone (truncated cone), oblique truncated cone (truncated truncated cone), oblique elliptical truncated cone (truncated elliptical cone), four Arbitrary ring structures composed of side surfaces such as truncated pyramid (truncated quadrangular pyramid), oblique quadrangular pyramid (truncated oblique pyramid), etc. are mentioned. A truncated cone and an elliptical truncated cone are preferable.

The nonwoven fabric 10 having the first and second projecting portions 11 and 12 arranged as described above does not have a bent portion, and is configured by a curved surface that is continuous as a whole. The said bending part means the part which a surface bends and has a corner | angular part.
Thus, it is preferable that the said nonwoven fabric 10 has a structure continuous in the surface direction. This “continuous” means that there are no intermittent portions or small holes. However, fine holes such as gaps between fibers are not included in the small holes. The small hole can be defined, for example, as a hole having a diameter equivalent to a circle of 1.0 mm or more.

  The fiber material that can be used for the nonwoven fabric 10 of the present invention is not particularly limited. Specific examples include the following fibers. There are fibers using a polyolefin resin such as polyethylene (PE) and polypropylene (PP), a polyester resin such as polyethylene terephthalate (PET), and a thermoplastic resin such as a polyamide-forming resin, and a core-sheath type, There are composite fibers having a side-by-side structure. In the present invention, it is preferable to use a composite fiber. Examples of the composite fiber include a core-sheath fiber having a high melting point component as a core portion and a low melting point component as a sheath portion, and a side-by-side fiber in which a high melting point component and a low melting point component are arranged in parallel. Preferable examples thereof include core-sheath fibers in which the sheath component (low melting point component) is polyethylene or low-melting polypropylene. Typical examples of the core-sheath fibers are PET (core) and PE (sheath). , PP (core) and PE (sheath), polylactic acid (core) and PE (sheath), PP (core) and low-melting point PP (sheath), etc. More specifically, the constituent fibers preferably 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). Moreover, these fibers may be used alone to constitute a nonwoven fabric, or may be used as a mixed fiber in which two or more kinds are combined.

Next, the dimension specification in the nonwoven fabric 10 of this embodiment is demonstrated below.
As shown in FIG. 6, regarding the thickness of the sheet, the total thickness when the nonwoven fabric 10 is viewed from the side is the sheet thickness TS, and the thickness of the local cross section of the sheet curved by the unevenness is the layer thickness. TL. The sheet thickness TS may be appropriately adjusted depending on the application, and when used as a surface sheet for diapers, sanitary products, etc., it is preferably 1 mm or more and 7 mm or less, and more preferably 1.5 mm or more and 5 mm or less. By setting it as the range, the body fluid absorption speed at the time of use is high, the liquid return from an absorber is suppressed, and also moderate cushioning property is realizable. The layer thickness TL may be different in each part in the sheet, and may be appropriately adjusted depending on the application. When used as a surface sheet for diapers, sanitary products, etc., the layer thickness TL1 of the first protrusion top 11T is preferably 0.1 mm or more and 3 mm or less, and more preferably 0.4 mm or more and 2 mm or less. The preferable range of the layer thickness is the same for the layer thickness TL2 of the second protrusion top 12T and the layer thickness TL3 of the wall 13. The relationship between the layer thicknesses TL1, TL2, and TL3 is preferably TL1>TL3> TL2. Thereby, in the 1st protrusion part 11, especially on the skin surface side, fiber density is low and can implement | achieve favorable skin contact. On the other hand, the second protrusion 12 has a high fiber density, is not easily crushed, and can be made of a nonwoven fabric excellent in cushioning properties and liquid absorption speed without being deformed.
As shown in FIG. 7, the distance Dx when the first protrusion top part 11T and the second protrusion top part 12T in the first direction X are projected onto a plane may be appropriately adjusted depending on the application, such as diapers and sanitary items. When used as a top sheet, it is preferably from 1 mm to 15 mm, and more preferably from 3 mm to 10 mm. Further, as indicated by the reference numerals in the parentheses in the drawing, the distance Dy when the first protrusion top 11T and the second protrusion top 12T in the second direction Y are projected onto a plane is the same as the distance Dx in the first direction X. . The basis weight of the nonwoven fabric 10 is not particularly limited, but is preferably 15 g / ^{m 2} or more 50 g / ^{m 2} or less the average value of the entire sheet, 20 g / ^{m 2} or more 40 g / ^{m 2} or less is more preferable.

The nonwoven fabric 10 demonstrated by the said embodiment has the following effects.
Even when a large amount of liquid is excreted or under high load, the nonwoven fabric 10 can reduce the amount of liquid remaining and the amount of liquid returned, and suppress the liquid flow on the surface. Since the liquid can be prevented from leaking, both prevention of liquid flow on the skin contact surface and prevention of liquid return from the non-skin contact surface side can be achieved.

  Furthermore, even if solid content, a highly viscous liquid, or the like is supplied, the first protrusion 11 on the non-skin contact surface side of the nonwoven fabric due to a series of first protrusions 11T connected through the ridge 15 Since the space due to the continuous internal space 11K is continuous in two directions, higher air permeability is obtained by the space. When a large amount of liquid is supplied, the captured large amount of liquid can be diffused in the continuous direction of the space, and the continuous leakage of the first protrusions 11 can prevent the liquid leakage in the lateral direction.

The said nonwoven fabric 10 is excellent in the excretion capture | acquisition property.
In the nonwoven fabric 10 of this embodiment, since it has internal space 11K and 12K inside each of the 1st, 2nd protrusion parts 11 and 12 which protrude on both surfaces, it is various according to the physical property of excretion liquid and excrement. These can be captured and dealt with in various forms. For example, when the first surface side Z1 of the nonwoven fabric 10 is described as the skin surface side, if the excretory liquid has a low viscosity and is easily permeable, after passing through the top sheet of the nonwoven fabric 10, this is captured in the internal space 11K. The portion that first hits the skin surface is the first protrusion top 11T, and the captured excretory fluid or excrement is made difficult to contact the skin. Thereby, even after excretion of urine, menstrual blood, descending products, etc., a very good and smooth feeling is sustained in a wide range.

Next, a preferred embodiment of the method for producing the nonwoven fabric 10 will be described below with reference to FIG.
The following manufacturing method should just be employ | adopted for the manufacturing method of the above-mentioned nonwoven fabric 10 suitably.

As an example of the support, the support 110 having the configuration shown in FIG. The support 110 has a large number of protrusions 111 corresponding to positions where the second protrusions 12 are shaped, and holes 112 are arranged corresponding to positions where the first protrusions 11 are shaped. Yes. That is, the support 110 has an uneven shape, and the protrusions 111 and the holes 112 are alternately arranged in different directions. For example, the protrusions 111 and the holes 112 in the first direction X and the second direction Y, respectively. And are arranged alternately.
Moreover, the support body 110 is heated.
As a method for heating the support 110, heat is transferred to the support 110 itself to heat it. That is, this is a method of directly heating the support 110 with a heat source (not shown). For example, a heater provided with a heating wire may be provided on the back side of the support 110 on which the protrusions 111 are not provided. Alternatively, the support 110 may be warmed by blowing hot air before the web 50 is conveyed onto the support 110. When the first hot air W1 is finally blown, any heating means may be used as long as the temperature of the support 110 is within an appropriate temperature range.
The temperature which heats the support body 110 shall be temperature more than the glass transition point of the fiber which comprises a web, and below melting | fusing point. It is considered that by setting the support 110 to a temperature equal to or higher than the glass transition point of the fiber, the web 50 is easily plastically deformed and is likely to have a shape along the support 110. That is, it becomes easy to shape the web 50 along the shape of the support 110. On the other hand, if the heating of the support 110 is too low, the difference between the height of the first protrusion 11 and the height of the ridge 15 is small, and the rising angle of the wall does not become steep. If the first protruding portion top 11T is hydrophobized in this state, a large amount of liquid is excreted on the surface of the nonwoven fabric when a high load is applied to the nonwoven fabric 10 (seat pressure). It is easy to leak and leak. On the other hand, if the heating is too low, the uneven shape is liable to be crushed regardless of the hydrophobicity, which is not preferable. On the other hand, if the heating of the support 110 is too high, the fibers are fused together and cannot be shaped.
The temperature of the supporting body 110 is preferably set to the above temperature range when the first hot air W1 described in the next step is blown.

A web 50 (also referred to as a fiber web) obtained by hydrophilizing hydrophobic thermoplastic fibers with a hydrophilizing oil is used. A known method can be used for the hydrophilic treatment. When the web 50 is disposed on the support 110 and the first hot air W1 is blown toward the web 50, the first hot air W1 corresponding to the hole 112 of the support 110 is shown in FIG. 8B. The protrusion 11 is shaped, and the second protrusion 12 is shaped corresponding to the position of the protrusion 111. Accordingly, the first projecting portion 11 projecting to the first surface side Z1 on the side in plan view and having the internal space 11K, and the second projecting portion projecting to the second surface side Z2 opposite to the first surface side Z1 and having the internal space 12K. The protrusions 12 are alternately and continuously arranged in different first directions X and second directions Y that intersect in plan view, and the web 50 is shaped.
In that case, the 1st protrusion part 11 turns into a truncated-cone with the top part having a roundness like a part of a hemisphere where the rising angle of a wall part is steeper than the cone with a round part like a hemisphere. The rising angle α of the wall portion 13 of the first projecting portion 11 is preferably set as described above.
The arrows in the drawing schematically show the flow of the first hot air W1.

Specific examples of this production method include the following embodiments.
The web 50 before being fused is supplied from a card machine (not shown) to a device for shaping the web so as to have a predetermined thickness. As shown in FIG. 8A, in the shaping apparatus, first, the web 50 is conveyed and fixed on the support 110 heated to the above temperature.
The heating temperature of the support 110 is a temperature not lower than the glass transition point of the fiber to be shaped and not higher than the melting point, preferably higher than the glass transition point of the fiber and not higher than 10 ° C. below the melting point. Preferably, the temperature is 20 ° C. higher than the glass transition point of the fiber and 20 ° C. lower than the melting point. For example, when using a composite fiber as the thermoplastic fiber, the glass transition point of the high glass transition point component is not lower than the glass transition point of the high glass transition point component and not more than 10 ° C. lower than the melting point of the low melting point component. The temperature is 20 ° C. or higher and 20 ° C. or lower than the melting point of the low melting point component. For example, when a fiber having a core / sheath structure of PET (core) having a glass transition point of 67 ° C. and a melting point of 258 ° C./PE (sheath) having a glass transition point of −20 ° C. and a melting point of 135 ° C. is used as the fiber. It is heated to not lower than 125 ° C. and preferably not lower than 87 ° C. and not higher than 115 ° C. If the heating temperature is too low, shaping along the shape of the support 110 cannot be performed, and the difference in height between the first protrusion 11 and the ridge 15 (see FIGS. 1 and 2) does not increase. For this reason, when the amount of the liquid flowing on the surface of the nonwoven fabric 10 under a high load becomes large, leakage easily occurs. On the other hand, if the heating temperature of the support 110 is too high, fusion between fibers occurs, or fusion to the support 110 occurs, and the desired shape cannot be formed.

Next, the first hot air W1 is blown onto the web 50 on the support 110 (the state shown in FIG. 8A). Then, the web 50 is shaped so as to follow the shape of the support 110 (the state shown in FIG. 8B). The temperature of the first hot air W1 at this time is preferably 0 ° C. to 70 ° C. lower than the melting point of the thermoplastic fiber constituting the web 50 in consideration of a general fiber material used for this type of product. More preferably, the temperature is 5 to 50 ° C lower. The wind speed of the first hot air W1 is set to 20 m / s or more and 150 m / s or less, preferably 30 m / s or more and 100 m / s depending on the height of the protrusions 111 of the support 110, from the viewpoint of shaping and texture. It is as follows. When the wind speed is slower than this lower limit, the film is not sufficiently shaped, and the effects of cushioning properties, excrement stock properties and breathability are not fully exhibited. When the wind speed exceeds this upper limit value, will be opening occurs in the second projecting portion 1 2 of the top 1 2T, easily crushed, stock and breathability of the effect of cushioning the excrement is not sufficiently exhibited . Furthermore, it becomes easy for excrement to go back through the opening.
In this way, the web 50 is shaped into a concavo-convex sheet.

  In addition, the height of the protrusion 111 of the support 110 is appropriately determined depending on the thickness of the entire sheet to be shaped and the layer thickness of the sheet. For example, it is set to 1 mm or more and 10 mm or less, preferably 1.5 mm or more and 9 mm or less, more preferably 2 mm or more and 8 mm or less.

  Next, as shown in FIG.8 (c), the 2nd hot air W2 of the temperature in which each fiber of the web 50 can be fuse | melted moderately is blown, and the fibers are fused and fixed. The temperature of the second hot air W2 at this time is preferably 0 ° C. to 70 ° C. higher than the melting point of the thermoplastic fiber constituting the web 50 in consideration of a general fiber material used for this type of product. More preferably, the temperature is 5 to 50 ° C higher. The wind speed of the second hot air W2 is set to 1 m / s or more and 10 m / s or less, preferably 3 m / s or more and 8 m / s or less. If the wind speed of the second hot air W2 is too slow, heat cannot be transferred to the fibers, the fibers are not fused together, and the uneven shape is insufficiently fixed. On the other hand, if the wind speed is too high, the fiber will be too hot and the texture will tend to be poor.

  As the thermoplastic fiber, the fiber described above is used. For example, when a composite fiber containing a low melting point component and a high melting point component is used as the thermoplastic fiber, the temperature of the second hot air W2 sprayed on the web 50 is equal to or higher than the melting point of the low melting point component and lower than the melting point of the high melting point component. It is preferable. More preferably, the temperature is at least 10 ° C lower than the melting point of the high melting point component, more preferably at least 5 ° C higher than the melting point of the low melting point component, and more preferably at least 20 ° C lower than the melting point of the high melting point component. .

  Moreover, it is preferable that the web 50 contains 30 mass% or more and 100 mass% or less of thermoplastic fiber, More preferably, it is 40 mass% or more and 100 mass% or less. The web 50 may include fibers that are not inherently heat-fusible (for example, natural fibers such as cotton and pulp, rayon and acetate fibers).

Next, the hydrophobization of the first protrusion top 11T will be described.
The non-woven fabric 10 basically has a high cushioning property even when the first protrusion top 11T is not hydrophobized, maintains an uneven shape even under high load, and adheres discharged liquid to the skin. The effect of the present invention that can be suppressed is exhibited. Furthermore, since the 1st protrusion part top part 11T is hydrophobized, since adhesion of the discharge liquid to skin can further be suppressed, it is more preferable.
The hydrophobizing method is not particularly limited, and examples include gravure coating and screen coating.
Or it is also possible to employ | adopt the following methods.
Prepare a plate having a non-deformable flat coating surface that has been coated with a hydrophobic agent in advance, and place the nonwoven fabric 10 so that the coating surface of the hydrophobic agent is in contact with each first protrusion 11 of the nonwoven fabric 10 evenly. To do. Then, assuming a use state of the infant, a constant pressure is applied to the first protrusion 11 of the nonwoven fabric 10 by placing a weight on the plate so that a pressure of 0.5 kPa to 3.5 kPa is applied. With this pressure, the hydrophobic agent applied to the application surface soaks into the first protrusion top 11T that is in contact with the application surface, and a hydrophobic portion 11D is formed on the first protrusion 11T (see FIG. 1). By using the weight, it is possible to apply a load evenly to each first protrusion top 11T, and to transfer the hydrophobic agent evenly to each first protrusion top 11T. That is, the hydrophobic portion 11D can be formed with high accuracy. Then, the hydrophobic agent soaked into the first protrusion top portion 11T is diffused in all directions in the first protrusion top portion 11T. The pressure due to the weight can be appropriately adjusted so as to obtain a desired effect of further suppressing the adhesion of the discharged liquid to the skin.
As described above, as shown in Examples 4 to 9 described later, the plate is subjected to a hydrophobizing treatment by applying a pressure of 0.5 kPa or more and 3.5 kPa or less to the plate so that the hydrophobic agent is soaked into the first protrusion top portion 11T. In addition, an effect of reducing the liquid return amount can be obtained.
In order to make the area St2 (not shown) of the second surface side Z2 of the hydrophobic portion 11D wider than the area St1 (not shown) of the first surface side Z1 of the hydrophobic portion 11D in the first protruding portion top portion 11T, There is a method of injecting a hydrophobic agent (for example, a hydrophobic oil agent) into the first protrusion top 11T from a nozzle (not shown), such as a method of increasing the injection depth of the nozzle and injecting from the vicinity of the second surface side Z2. It is done. By changing the injection depth of the nozzle, the area ratio between the area St1 on the first surface side Z1 of the hydrophobic portion 11D and the area St2 on the second surface side Z2 of the hydrophobic portion 11D can be changed. Further, the fineness of the second surface side Z2 of the thermoplastic fiber used for the web 50 is made smaller than the fineness of the first surface side Z1, and the fiber density of the second surface side Z2 is made to be the fiber density of the first surface side Z1. It can also be achieved by making it higher. This is because the hydrophobic agent soaked into the first protrusion top 11T diffuses more on the second surface side Z2 than on the first surface side Z1. Furthermore, the hydrophobic area of the hydrophobic portion 11D is preferably adjusted so that the amount of liquid return is effectively reduced in the usage state.

  As the hydrophilic agent used for the hydrophilic treatment, various known ones can be used without particular limitation. For example, a hydrophilic oil agent is used. The hydrophilic oil agent is generally an anionic, cationic, amphoteric or nonionic surfactant, and is not particularly limited thereto. These can be used in the form of an aqueous solution or emulsion having a predetermined concentration. Preferred hydrophilizing agents include aliphatic monocarboxylate, polyoxyethylene alkyl sulfate, polyoxyethylene alkyl phosphate, glycerin fatty acid ester, sorbitan fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkyl ether, fatty acid polyethylene Examples include glycols, alkylamine salts, and alkylbetaines.

  Specific examples of the hydrophobic agent include silicone oligomers and fluorine oligomers. The silicone oligomer is typically a chain polydimethylsilicone, such as a modified silicone in which a methyl group is partially replaced with a polyether, a phenyl group or a trifluoropropyl group. In the fluorine oligomer, as a water / oil repellent, an acrylic ester polymer of alcohol containing a perfluoroalkyl group or a phosphate ester is used. The characteristics of the silicone water repellent are excellent in water repellency and flexibility, and are suitable for the treatment of a surface agent that directly contacts the skin. The fluorine-based water repellent exhibits the most excellent water repellency in the region, and has an advantage that the water repellency can be maintained even when in contact with a surfactant for hydrophilicity.

The nonwoven fabric 10 is produced as described above.
In the manufacturing method, considering continuous production, a manufacturing apparatus (not shown) is a conveyor type or a drum type capable of transporting the support 110, and a sheet having a concavo-convex shape to be conveyed is fixed, The mode which winds up with a roll (not shown) is mentioned.

  In the said manufacturing method, the thickness of each sheet | seat is suitably determined by the wind speed of the 1st hot air W1. For example, when the wind speed is increased, the thickness of the sheet is increased, and when it is decreased, the thickness of the sheet is decreased. Further, when the wind speed is increased, the fiber density difference between the first protrusion and the second protrusion is increased, and when the wind speed is decreased, the fiber density difference between the first protrusion and the second protrusion is decreased.

  The nonwoven fabric 10 of the present invention can be used for various applications. For example, it can be suitably used as a surface sheet for absorbent articles such as disposable diapers, sanitary napkins, panty liners, urine absorption pads and the like. Furthermore, since the both surfaces of the nonwoven fabric 10 are excellent in air permeability, liquid diffusibility, deformation characteristics at the time of pressing force, etc. due to the concavo-convex structure, between the surface sheet such as diapers and sanitary products and the absorbent body It can also be used as a sub-layer interposed between. In addition, the form utilized as a gather of an absorbent article, an exterior sheet, and a wing is also mentioned. Furthermore, the form utilized as a wiping wipe sheet | seat, a cleaning sheet | seat, and a filter is also mentioned.

  Next, an application example of the disposable diaper 100 to the main body 4 will be described below as a preferred embodiment of an absorbent article using the nonwoven fabric according to the present invention as a top sheet with reference to FIG. The disposable diaper shown in the figure is a tape-type disposable diaper for infants, and is shown in a state where the diaper developed in a plane is bent slightly and viewed from the inside (skin contact surface side).

As shown in FIG. 9, the disposable diaper 100 includes a liquid permeable top sheet 1 disposed on the skin contact surface side, a liquid poorly permeable back sheet 2 disposed on the non-skin contact surface side, and the above-mentioned A liquid-retaining absorbent 3 is disposed between both sheets.
The nonwoven fabric 10 of the said embodiment is applied to the surface sheet 1, and the 1st protrusion part 11 side is made into the skin contact surface.

The back sheet 2 is in an unfolded state, and both side edges thereof have a shape confined to the inside in the longitudinal central portion C. Even if the back sheet 2 is composed of a single sheet, it is composed of a plurality of sheets. Also good.
The back sheet 2 is not particularly limited as long as it has waterproofness and moisture permeability. For example, a minute inorganic filler composed of a hydrophobic thermoplastic resin and calcium carbonate or an incompatible organic polymer. And the like, and a porous film obtained by uniaxially or biaxially stretching the film. Examples of the thermoplastic resin include polyolefin. Examples of the polyolefin include high-density to low-density polyethylene, linear low-density polyethylene, polypropylene, polybutene, and the like, and these can be used alone or in combination.

As the absorbent body 3, various forms used for this type of article can be widely adopted as long as they have liquid retention. For example, there are various types such as those in which pulp fibers are coated with a core wrap sheet, sheets in which an airlaid nonwoven is used, and sheets in which a superabsorbent polymer is sandwiched between fiber sheets. Examples of the pulp fiber include wood pulp such as softwood kraft pulp and hardwood kraft pulp, and natural cellulose fiber such as non-wood pulp such as cotton pulp and straw pulp. In addition, polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, single fibers made of synthetic resins such as polyvinyl alcohol resins, composite fibers containing two or more of these resins, semi-synthetic materials such as acetate and rayon Fibers may be included in part. Further, as the superabsorbent polymer, various polymer materials usually used for this type of article can be used. The water-absorbing polymer is preferably a superabsorbent polymer compound capable of absorbing and retaining water or saline more than 20 times its own weight.
In addition, the coated sheet is a hydrophilic member, for example, thin paper (thin paper) such as hydrophilic tissue paper, crepe paper, non-woven fabric made of hydrophilic fibers such as cotton and rayon, and synthetic resin fibers. A non-woven fabric formed by treatment, for example, an air-through non-woven fabric, a point bond non-woven fabric, a spunlace non-woven fabric, a spunbond non-woven fabric, a spunbond-meltblown-spunbond (SMS) non-woven fabric or the like can be used.

  The side sheet 5 is preferably a water-repellent non-woven fabric, and is water-repellent from among non-woven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics, heat roll nonwoven fabrics, needle punched nonwoven fabrics manufactured by the card method, Various non-woven fabrics treated with water can be used. Particularly preferably, for example, a spunbond nonwoven fabric, a spunbond-meltblown (SM) nonwoven fabric, a spunbond-meltblown-spunbond (SMS) nonwoven fabric, or the like is used.

  In this example, a side leakage prevention gather 7 formed by the side seats 5 is provided, whereby side leakage of liquid or the like in the hip joint portion due to movement of the infant can be effectively prevented. In the diaper of this embodiment, a functional structure part, a sheet material, etc. may be provided. In addition, in FIG. 9, the arrangement | positioning relationship and boundary of each member are not illustrated strictly, and if it is set as the general form of this kind of diaper, the structure will not be specifically limited.

  The diaper is shown as a tape type, and a fastening tape 6 is provided on the flap portion on the back side R. Fastening tape 6 can be affixed to a tape affixing part (not shown) provided in the flap part of ventral side F, and a diaper can be mounted and fixed. At this time, the center part C of the diaper is gently bent inward so that the absorbent body 3 is worn along the baby's buttocks and lower abdomen. As a result, excreta is absorbed and held in the absorber 3 accurately. By using in such a form, the skin contact surface even when a large amount of liquid is excreted or when it is under a high load, particularly by applying the nonwoven fabric 10 as the top sheet 1 It is possible to achieve both prevention of the liquid flow above and prevention of liquid return from the non-skin contact surface side. Further, higher air permeability is obtained by the space formed by the continuous internal space 11K, and a large amount of the captured liquid can be diffused in the continuous direction of the space, thereby preventing liquid leakage in the lateral direction. Furthermore, since the excreted fluid or excreted material that has been captured is made difficult to come into contact with the skin, after excretion of urine, menstrual blood, descending material, etc., a very good smooth feeling can be sustained widely.

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

This invention discloses the manufacturing method of the following nonwoven fabrics, the surface sheet for absorbent articles, an absorbent article, and a nonwoven fabric further regarding embodiment mentioned above.
<1> a first protrusion that protrudes toward the first surface of the sheet body in a plan view and has an internal space;
A second projecting portion projecting on the second surface side opposite to the first projecting portion and having an internal space;
A plurality of the first protrusions and the second protrusions are alternately and continuously arranged through wall portions in different directions intersecting in plan view of the nonwoven fabric,
The adjacent first protrusions and the adjacent second protrusions are nonwoven fabrics that are continuously connected in an oblique direction in plan view with respect to each of the different directions via the ridges, respectively.
When pressurizing the nonwoven fabric at a pressure of 0.05 kPa,
The height in the thickness direction of the first protrusion is higher than the height in the thickness direction of the ridge,
The nonwoven fabric whose rise angle of the wall part of the said 1st protrusion part is 0 degree or more and 20 degrees or less.
<2> The rising angle of the wall portion of the first protrusion is preferably greater than 0 ° and 20 ° or less, more preferably greater than 0 ° and 15 ° or less, and greater than 0 °. The nonwoven fabric according to <1>, more preferably 12 ° or less.
<3> The fibers constituting the wall have fiber orientation in a direction connecting the top of the first protrusion and the edge of the opening of the internal space of the first protrusion <1>. Or the nonwoven fabric as described in <2>.
<4> The nonwoven fabric according to any one of <1> to <3>, wherein the fiber constituting the wall portion has fiber orientation in a direction in which the wall portion stands.
The fiber which comprises the <5> said wall part is a nonwoven fabric any one of <1> to <4> which has radial fiber orientation which goes to the said 1st protrusion part top part.
<6> The fibers constituting the wall of the second protrusion have fiber orientation in the direction connecting the top of the second protrusion and the edge of the opening of the internal space. <1> to <5> The nonwoven fabric of any one.
<7> The nonwoven fabric according to any one of <1> to <6>, wherein the orientation angle of the wall portion is 50 ° to 130 °, and the orientation strength is 1.05 or more.
<8> The nonwoven fabric according to any one of <1> to <6>, wherein the wall has an orientation angle of 60 ° to 120 ° and an orientation strength of 1.10 or more.
<9> The nonwoven fabric according to any one of <1> to <6>, wherein the wall has an orientation angle of 85 ° to 95 ° and an orientation strength of 1.30 or more.
<10> Any one of <1> to <9>, wherein when the nonwoven fabric is pressurized at a pressure of 3.5 kPa, the height in the thickness direction of the first protrusion is higher than the height in the thickness direction of the ridge. The nonwoven fabric described in 1.
<11> The ratio (h1 / h5) between the height h1 in the thickness direction of the first protrusion and the height h5 of the ridge when the nonwoven fabric is pressurized at a pressure of 3.5 kPa is as follows. It is preferably 01 or more, more preferably 1.05 or more, further preferably 1.2 or more, and the upper limit is preferably 2.5 or less, and is 2.0 or less. The nonwoven fabric according to any one of <1> to <10>, more preferably 1.8 or less.
<12> The first projecting portion is a truncated cone having a steeper rising angle of the wall portion than a cone having a round shape like a hemisphere, and the top portion having a round shape like a part of a hemisphere < The nonwoven fabric according to any one of <1> to <11>.
<13> The nonwoven fabric according to any one of <1> to <12>, wherein the hydrophilicity of the top of the first protrusion is lower than that of the second protrusion and the wall.
<14> The nonwoven fabric according to any one of <1> to <13>, wherein the hydrophilicity of the top of the first protrusion is lower than the hydrophilicity of the ridge.
<15> The top of the first protrusion has a contact angle of ion exchange water at 22 ° C. of 80 ° or more, preferably 100 ° or more,
The preferred contact angle between the top of the second protrusion and the wall is such that the contact angle of the ion exchange water is 30 ° or more and less than 80 °, preferably 60 ° or more and 70 ° or less <1> to <14. > Any one of>.
Any one of <1> to <14>, wherein the <16> ridge has a contact angle of ion-exchanged water at 22 ° C. of 30 ° or more and less than 80 °, preferably 60 ° or more and 70 ° or less. The nonwoven fabric described in 1.
<17> On both the first surface side and the second surface side, the hydrophilicity of the top portion of the first protruding portion is lower than the portion excluding the top portion of the first protruding portion, or has hydrophobicity. The non-woven fabric according to any one of <1> to <16>, wherein the area of the first surface side at the top of the first protruding portion is less hydrophobic than the second surface side.
<18> The nonwoven fabric according to any one of <1> to <17>, wherein the two different directions are orthogonal to each other.
<19> The nonwoven fabric according to any one of <1> to <18>, wherein the wall portion forms an annular structure in the first projecting portion and the second projecting portion.
<20> The layer thickness TL1 of the top of the first protrusion, the layer thickness TL2 of the top of the second protrusion, and the layer thickness TL3 of the wall are TL1>TL3> TL2, and any one of <1> to <19> Or the nonwoven fabric according to 1.
<21> A topsheet for an absorbent article using the nonwoven fabric according to any one of <1> to <20>.
<22> A surface sheet for absorbent articles, wherein the nonwoven fabric according to any one of <1> to <20> is used with the first surface side facing the skin contact surface side.
<23> An absorbent article using the nonwoven fabric according to any one of <1> to <20> as a surface sheet.
<24> An absorbent article using the nonwoven fabric according to any one of <1> to <20> as a surface sheet with the first surface side facing the skin contact surface side.
<25> A concavo-convex shape is formed, a web containing thermoplastic fibers is conveyed to a heated support, and hot air is blown from the top of the web toward the support to shape the concavo-convex shape on the web. A method for producing a nonwoven fabric, comprising:
Heating the support to a temperature range from the glass transition point to the melting point of the fibers constituting the web; and
Temporarily fusing the fibers of the web to a state in which the uneven shape is maintained by blowing a first hot air; and
A step of blowing a second hot air having a temperature higher than that of the first hot air, and fixing the uneven shape by fusing the fibers of the web while maintaining the uneven shape. Production method.
<26> The temperature range for heating the support is preferably a temperature higher than the glass transition point of the fiber and 10 ° C. or lower than the melting point, more preferably a temperature 20 ° C. higher than the glass transition point of the fiber. As mentioned above, the manufacturing method of the nonwoven fabric as described in <25> below 20 degrees C lower than melting | fusing point.
<27> The method for producing a nonwoven fabric according to <25> or <26>, wherein the temperature of the support is within the temperature range when the first hot air is blown.
<28> Furthermore, the manufacturing method of the nonwoven fabric any one of <25> to <27> including the process of hydrophobizing the top part of the 1st protrusion part used as the said uneven | corrugated shaped convex part.
<29> A nonwoven fabric produced using the nonwoven fabric production method according to any one of <25> to <28>.
<30> A surface sheet for absorbent articles using the nonwoven fabric according to <29>.
<31> An absorbent article using the nonwoven fabric according to <29> as a surface sheet.

  Hereinafter, the present invention will be described in more detail based on examples. The present invention is not construed as being limited by these examples.

[Example 1-9]
Example 1 is 2.4 dtex in which the core is made of polyethylene terephthalate (melting point 258 ° C., glass transition point 67 ° C.), the sheath is made of polyethylene (melting point 135 ° C., glass transition point −20 ° C.), and the surface is hydrophilized. A core-sheath type composite fiber of × 51 mm was supplied as a web 50 from the card machine to the shaping apparatus so as to have a basis weight of 30 g / m ² . In the shaping apparatus, the web 50 was fixed on the support 110 having a large number of protrusions and air permeability. The support 110 is heated to 70 ° C. The MD pitch in the plan view of the protrusion 111 of the support 110 was 8 mm, the CD pitch was 5 mm, and the height of the protrusion 111 was 7.5 mm. Moreover, the hole diameter of the hole 112 in the support body 110 was 2.8 mm.
Next, the first hot air W <b> 1 (temperature 130 ° C., wind speed 50 m / s) is blown onto the web 50 on the support 110, and the web 50 is shaped along the protrusions 111 on the support 110. Next, it switched to the 2nd hot air W2 of temperature 145 degreeC and the wind speed of 5 m / s, the fibers of each core-sheath structure were fused together, and the shaping shape was fixed. The support 110 is heated to 70 ° C. when the first hot air W1 is blown. Thus, the nonwoven fabric 10 was produced.
Example 2 was produced in the same manner as in Example 1 except that the heating temperature of the support 110 in Example 1 was changed to 90 ° C.
Example 3 was produced in the same manner as in Example 1 except that the heating temperature of the support 110 was 110 ° C. in Example 1 above.
In Example 4, the nonwoven fabric 10 of Example 1 was produced, and the hydrophobic treatment was further performed. KM-903 (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the hydrophobic agent, and the hydrophobic agent was dissolved in ethanol, adjusted to a 1.0 wt% solution, and applied to an acrylic plate at 4.3 mg / cm ² . Hydrophobic part 11D was produced by bringing the pressure of 2.0 kPa into contact with the first protrusion top part 11T over 10 seconds.
Example 5 was produced in the same manner as in Example 4 except that the heating temperature of the support 110 was changed to 90 ° C. in Example 4.
Example 6 was produced in the same manner as in Example 4 except that the heating temperature of the support 110 was changed to 110 ° C. in Example 4.
Example 7 was produced in the same manner as in Example 5 except that KF-6011 (manufactured by Shin-Etsu Chemical Co., Ltd.) was used as the hydrophobic agent in Example 5.
Example 8 was prepared in the same manner as in Example 5 except that the web 50 was a two-layer product of core-sheath type composite fiber 2.4 dtex × 51 mm and 1.8 dtex × 51 mm.
Example 9 was produced in the same manner as in Example 8, except that the pressure applied to the plate in Example 8 was 1.5 kPa.

[Comparative Example 1-3]
Comparative Example 1 was produced in the same manner as in Example 1 except that the heating temperature of the support 110 was 40 ° C. in Example 1.
Comparative Example 2 was produced in the same manner as in Example 4 except that the heating temperature of the support 110 was 40 ° C. in Example 4.
In Comparative Example 3, the non-woven fabric 10 of Comparative Example 2 was prepared, and a 1.0% by weight ethanol solution of KM-903 (manufactured by Shin-Etsu Chemical Co., Ltd.) was applied to the walls and ridges with a brush. This was prepared in the same manner as in Example 2 except that.

Next, a measurement method and an evaluation method will be described. The following measurement tests were performed using the above-mentioned nonwoven fabric test specimens.
<Support temperature measurement method>
Five seconds after stopping the shaping device, the temperature of the support at the position where the first hot air W1 was sprayed was measured using a contact thermometer. For the contact-type thermometer, ND500 manufactured by CHINO Co., Ltd. was used as the measuring instrument body, and C510-05K manufactured by CHINO Co., Ltd. was used as the measurement terminal. The temperature was measured three times, and the average value was defined as the support temperature.

<Measurement of fiber orientation (orientation angle, orientation strength)>
Using a scanning electron microscope JCM-5100 (trade name) manufactured by JEOL Ltd., the sample is allowed to stand so that the z-axis direction in FIG. An image taken from the direction (adjusted to a magnification capable of measuring 10 or more fibers to be measured; 100 to 300 times) was printed, and the fibers were traced on a transparent PET sheet. The said image was taken in in the personal computer and the said image was binarized using the NexusNewQube [tradename] (stand-alone version) image processing software. Next, the binarized image was subjected to Fourier transform using Fiber Orientation Analysis 8.13 Single software (trade name), which is a fiber orientation analysis program, to obtain a power spectrum, and from an elliptical distribution map, an orientation angle was obtained. And the orientation strength was obtained.
The orientation angle indicates the angle at which the fibers are most oriented, and the orientation strength indicates the strength at the orientation angle. In the measurement of the middle portion of the wall, the orientation angle close to 90 ° indicates that the fibers are oriented in the central direction of the top portion 11T. If the orientation angle is 60 ° or more and 120 ° or less, the center direction of the top portion 11T It is determined that the fibers are oriented.
Moreover, it represents that the direction of a fiber has gathered, so that the value of orientation strength is large. The case where the orientation strength is 1.05 or more is assumed to be oriented.
Measurement was performed at three locations, and the average was taken as the orientation angle and orientation strength of the sample.

The fiber orientation described above is a concept consisting of the orientation angle and orientation strength of the fiber.
The fiber orientation angle is a concept that indicates in which direction a plurality of fibers having various directions are oriented as a whole, and the shape of the fiber aggregate is quantified. The orientation strength of the fiber is a concept indicating the amount of fibers exhibiting an orientation angle. The orientation strength is less than 1.05 and is hardly oriented, and it can be said that the orientation strength is 1.05 or more. However, in this embodiment, the fiber orientation changes depending on the part. That is, the orientation strength is changed during the transition from a part having a certain orientation angle to a part having a different orientation angle (while the fiber is changing from a state in which the orientation strength is strong in one direction to a part having a strong strength in a different orientation). It has various states such as a weak state and a high state due to reorientation. Therefore, it is preferable that the orientation angle of the fiber is changed between the part showing a strong orientation angle and the part showing a strong orientation angle in another direction even if the orientation strength of the fiber is weak, and the orientation strength is high. Is more preferable. An example of the orientation angle and orientation strength is shown in this embodiment. The orientation angle is preferably 50 ° or more and 130 ° or less, more preferably 60 ° or more and 120 with respect to the curved surface structure of the wall portion 13 of the first protrusion 11. The orientation strength is preferably 1.05 or more, and more preferably 1.10 or more. The wall portion 14 of the second protrusion 12 is the same as the wall portion 13.
When the nonwoven fabric 10 is used as the top sheet of the absorbent article, the nonwoven fabric 10 has sufficient compression resistance even under high pressure due to the fiber orientation of each wall portion 13, and the first protrusion 11 of the nonwoven fabric 10, The crushing of the 2nd protrusion part 12 is prevented. As a result, a sufficient capture space can be ensured, and the effect of reducing the skin contact area, high air permeability, a large amount of liquid, solid content, highly viscous liquid, etc. can be sufficiently captured and the effect of suppressing leakage can be sufficiently exhibited.

<Measurement of thickness at 0.05 kPa pressure>
The cut surface of the non-woven fabric 10 is enlarged so that the portion measured by the digital microscope VHX-1000 manufactured by Keyence can sufficiently enter the field of view (10 times to 100 times) and a pressure of 0.05 kPa is applied. Is placed on the nonwoven fabric 10, and the height h1 of the first protrusion 11 in the thickness direction and the height h5 of the ridge portion 15 in the thickness direction are measured. The measurement was performed 10 times, and the average value was defined as the height h1 of the first protrusion top portion 11T of the nonwoven fabric 10 and the height h5 of the ridge portion 15.
<Measurement of thickness at 3.5 kPa pressure>
The measuring method of the height h1 of the first projecting portion 11T and the height h5 of the ridge portion 15 under a pressure of 3.5 kPa seems to apply a pressure of 3.5 kPa to the weight of the thickness measuring method at a pressure of 0.05 kPa. The procedure was the same except that the adjustment was made.

<Measuring method of contact angle CA (°)>
The specific method for measuring the contact angle was as follows. A contact angle meter is used to measure the contact angle. For example, a contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Specifically, after ion-exchanged water is dropped (about 20 picoliters) on the nonwoven fabric 10 to which the hydrophobic agent has been applied, the contact angle is measured immediately using the contact angle meter. The measurement is performed at five or more locations on the nonwoven fabric 10 and the average value thereof is taken as the contact angle. The measurement temperature is 22 ° C., and the relative humidity of the measurement atmosphere is 65%.
It is preferable that the 1st protrusion part top part 11T is hydrophobic, and it is preferable that the contact angle of ion-exchange water is 80 degrees or more. More preferably, it is 100 ° or more.
As a preferred contact angle of the portion excluding the first protrusion top 11T (second protrusion top 12T, wall 13 (14)), the contact angle of ion-exchanged water is 30 ° or more and less than 80 °. Preferably they are 60 degrees or more and 70 degrees or less. Therefore, the contact angle of the ridge portion 15 is preferably set to the above-described angle, and specifically, is preferably 30 ° or more and less than 80 °, and more preferably 60 ° or more and 70 ° or less. The lower the contact angle value measured here, the higher the hydrophilicity.

<Measurement method of rising angle>
The cut surface of the non-woven fabric 10 is enlarged to a size (10 to 100 times) that can be measured with a digital microscope VHX-1000 manufactured by Keyence, and the rising angle α of the first protrusion 11T is increased. taking measurement. As shown in FIG. 4B, the rising angle α draws a straight line Lv perpendicular to the straight line Lh connecting the top part 12T of the second projecting part 12, and the straight line Lv is drawn from this straight line and the second projecting part top part 12T. The angle α formed with the tangent Lt of the nonwoven fabric (web 50) on the second surface side Z2 drawn over the wall portion 14 is measured. The measurement was performed 10 times, and the average value was defined as the rising angle α of the wall 13 (14) of the first protrusion 11T of the nonwoven fabric 10.

<Measuring method of area of first surface side and area of second surface side of hydrophobic portion 11D>
In each of the first surface side and the second surface side of the hydrophobic portion 11D, the contact angle is measured every 0.2 mm, and the area where the contact angle is 80 ° or more is counted as the number of squares of 0.2 mm square. Thus, the area St1 on the first surface side and the area St2 on the second surface side of the hydrophobic portion 11D were set, respectively.

<Evaluation of compression recovery>
The compression recoverability was evaluated by performing compression property evaluation up to 5.0 kPa in a normal mode using a KES compression tester (KES FB-3 manufactured by Kato Tech Co., Ltd.) and reading the RC value. As measurement values, three points were measured and the average value was defined as compression recovery. This KES compression tester is a plate having a circular plane with an area of 2 cm ^{2 at} the compression site, the compression speed is 0.02 mm / s, the compression maximum pressure is 5.0 kPa, and the compression direction is reached when the compression maximum pressure is reached. Is reversed and the process proceeds to the recovery process. The RC value is expressed as a percentage of the energy recovered relative to the energy at the time of compression. The larger the RC value, the better the recovery against compression, the elasticity, and the better the cushioning property. The RC value in the compression characteristic evaluation is the time integral value of the pressure from the time T ₀ when the initial pressure applied to the nonwoven fabric specimen is 0.05 kPa to the time T _m when the maximum pressure is 5.0 kPa, up to the maximum pressure of 5.0 kPa. Divided by the amount of work and expressed in%.

<Measurement method of liquid return amount>
As an example of the absorbent article 100, the liquid return amount is measured by removing the topsheet from an infant diaper (Made by Kao Co., Ltd .: Merry's Sarah Air Through (registered trademark) M size, 2012), and testing the nonwoven fabric 10 instead. A baby diaper for evaluation obtained by using a body (hereinafter referred to as a nonwoven fabric test body) and fixing its periphery was used.
A pressure of 3.5 kPa was applied uniformly on the non-woven fabric test piece, a cylinder having a cross-sectional area of 1000 mm ² placed at the approximate center of the test piece was applied, and artificial urine was injected therefrom. As the artificial urine, physiological saline was used, and a total of 160 g of artificial urine was infused 4 times by 40 g every 10 minutes.
After standing for 10 minutes from the completion of the injection, the above cylinder and pressure were removed. And filter paper No. made by Advantech Co., Ltd. A weight adjusted so that a pressure of 3.5 kPa was applied to an absorbent sheet (mass = M1) in which 20 sheets of 5C (100 mm × 100 mm) were stacked was placed on the nonwoven fabric specimen around the injection point.
After standing for 5 minutes, the weight was removed, the mass (M2) of the filter paper was measured, and the amount of liquid return was calculated according to the following equation.

  Liquid return amount (g) = mass of filter paper after pressurization (M2) −mass of filter paper before pressurization (M1)

<Measurement method of liquid flow length>
The liquid flow of the artificial urine was measured by measuring the distance from the position where the artificial urine was supplied.
Obtained by removing the surface sheet from the baby diaper (Made by Kao Co., Ltd .: Marys Sarasara Air-Through (registered trademark) M size, 2012), and using the test piece of the nonwoven fabric 10 instead, fixing the periphery of the test piece. An evaluation baby diaper was used. A flat acrylic plate is tilted so that a 30 ° inclined surface can be obtained, the above-mentioned baby diaper is attached to the inclined surface and pressurized at 3.5 kPa, and in this state, the injection port arranged on the surface side of the baby diaper As an artificial urine, 40 g of physiological saline is injected into an infant diaper and the distance from the inlet to the lower end of the liquid is calculated as the amount of liquid flow from the inlet to the end of absorption of the liquid. (Longitudinal direction). In addition, when the injected liquid is absorbed obliquely from the longitudinal direction of the absorbent article, the shortest connecting the injection port and the lower end of the liquid absorbed obliquely along the longitudinal direction of the absorbent article The distance was the liquid flow length.

  Table 1 shows the results of the physical properties (support temperature, orientation angle, orientation strength, thickness, contact angle, hydrophobic part area) and performance (compression recovery (RC value), liquid return amount, liquid flow) of the nonwoven fabric 10. Shown in

As shown in Table 1 above, in Examples 1 to 9, the thickness of the first protrusion 11 at a pressure of 3.5 kPa was 2.6 mm or more, and the liquid return amount was 1.3 g or less. This is because the heating temperature of the support 110 is in a suitable range, so that shaping along the shape of the support 110 can be performed, the rising angle is 20 ° or less, and the nonwoven fabric 10 is not easily crushed in the thickness direction. is there. This shows that the RC value (%) is higher than that of the comparative example, and the cushioning property is improved.
In Examples 4 to 9, the liquid return amount was 0.8 g or less, and the liquid return amount decreased. This is because, in addition to the effects of the first to third embodiments, since the first protruding portion top portion 11T is hydrophobic on the first surface side Z1 that is the skin contact surface side, the remaining amount of the liquid that touches the skin This is because the liquid that overflows from the absorber is less likely to return to the first surface side Z1. The liquid flow length was 65 mm or less, and the liquid flow was small. This is because the heating temperature of the support 110 is in a suitable range, so that shaping can be performed along the shape of the support 110, and the difference in height between the first protrusion 11 and the ridge 15 is increased. This is because the liquid flow on the first surface side Z <b> 1 of the nonwoven fabric 10 flows in an oblique direction with respect to the first direction X and the second direction Y.
On the other hand, in Comparative Example 1, since the heating temperature of the support 110 is as low as 40 ° C., shaping along the shape of the support 110 cannot be performed, the rising angle becomes 30 °, and the nonwoven fabric 10 is easily crushed in the thickness direction. And since there was no hydrophobic part in the 1st protrusion part top part 11T, the liquid return amount increased with 1.5g. Moreover, since there is no hydrophobic part in the first protrusion top part 11T, the liquid flow rate is 58 mm regardless of the difference between the height h1 of the first protrusion 11 and the height h5 of the ridge part 15 under high load. It has become smaller.
Moreover, in Comparative Example 2 and Comparative Example 3, the liquid return amount was a little as 1.0 g and 0.9 g, and the liquid flow length was very long as 100 mm or more. This is because the heating temperature of the support 110 is as low as 40 ° C., so that shaping along the shape of the support 110 cannot be performed, and the difference in height between the first protrusion 11 and the ridge 15 has not increased. This is because the same effects as in the examples were not sufficiently exhibited.
As described above, in Examples 1 to 9, both the liquid return amount and the surface liquid flow length were suppressed to low values. Therefore, it was found that Examples 1 to 9 were able to achieve both liquid return prevention and surface liquid flow prevention that could not be achieved in Comparative Examples 1 to 3.

DESCRIPTION OF SYMBOLS 1 Top sheet 2 Back sheet 3 Absorber 4 Main body 5 Side sheet 6 Fastening tape 7 Side leakage prevention gather 10 Non-woven fabric 11 1st protrusion part 11D Hydrophobic part 11K Internal space 11T 1st protrusion part top part 12 2nd protrusion part 12K Internal space 12T 2nd protrusion top part 13,14 Wall part 15 Ridge part 100 Disposable diaper 110 Support body 111 Protrusion 112 Hole

Claims (6)

Production of a nonwoven fabric having a concavo-convex shape, transporting a web containing thermoplastic fibers to a heated support, and blowing hot air from above the web toward the support to shape the concavo-convex shape on the web A method,
After the step of heating the support to a temperature range not lower than the melting point and not higher than the glass transition point of the fibers constituting the web,
Temporarily fusing the fibers of the web to a state in which the uneven shape is maintained by blowing a first hot air; and
A method for producing a nonwoven fabric, comprising: blowing a second hot air having a temperature higher than that of the first hot air, and fixing the uneven shape by fusing the fibers of the web while maintaining the uneven shape. .   The method for producing a nonwoven fabric according to claim 1, wherein a temperature range for heating the support is not lower than a temperature higher than the glass transition point of the fiber and not higher than 10 ° C lower than the melting point.   3. The method for producing a nonwoven fabric according to claim 1, wherein the temperature range for heating the support is not less than a temperature 20 ° C. higher than the glass transition point of the fiber and not more than 20 ° C. lower than the melting point.   The temperature of the said support body is a manufacturing method of the nonwoven fabric of any one of Claim 1 to 3 used as the said temperature range when spraying a said 1st hot air.   The manufacturing method of the nonwoven fabric of any one of Claim 1 to 4 including the process of hydrophobizing the top part of the 1st protrusion part used as the said uneven | corrugated shaped convex part.   The non-woven fabric according to any one of claims 1 to 5, wherein a heater provided with a heating wire is disposed in a region on the back surface facing the surface side of the support excluding a region where the protrusions of the support are disposed. Production method.

Images