JP5507193B2 - Absorbent article surface sheet - Google Patents

Description

  The present invention relates to a surface sheet of an absorbent article.

  Conventionally, as a surface sheet of an absorbent article used for absorption of liquid discharged from the body, such as sanitary napkins, incontinence pads, panty liners, etc., by forming the surface directed to the skin side of the nonwoven fabric in an uneven shape, There is known a technique that prevents contact with the skin of the wearer and the non-woven cloth to prevent stuffiness and rash (see, for example, Patent Document 1). In addition, a technique is also known in which fiber layers with different fiber diameters are stacked to form a coarse / dense structure having a gradient in fiber density, thereby improving the drawability of the liquid (for example, see Patent Document 2).

  Further, a three-dimensionally shaped nonwoven fabric using a heat-extensible fiber having an uneven shape on at least one surface and extending its length by heating is known (see Patent Document 3).

JP 2007-97858 A JP-A-5-247816 JP 2005-350836 A

The surface sheet described in Patent Document 1 has an upper layer directed to the skin side and a lower layer containing heat-shrinkable fibers and directed to the absorber side, and contracts the lower layer by contraction of the heat-shrinkable fibers contained in the lower layer. Since it is obtained, the liquid tends to remain in the lower layer densified by heat shrinkage.
As for the surface sheet of patent document 2, the fiber diameter of the fiber which comprises the upper layer turned to the skin side is thicker than the fiber diameter of the fiber which comprises a lower layer. Therefore, the softness of the upper layer in contact with the skin side is inferior and the touch is not good.
Although the surface sheet of patent document 3 uses a heat | fever extensible fiber, since it is a single layer structure, control of a protruding structure is difficult and performances, such as a touch and an absorption performance, are hard to express stably.

  The present invention relates to a surface sheet of an absorbent article that hardly retains liquid in the surface sheet and has a good touch.

  The present invention is a two-layered surface sheet having an upper layer on the skin contact surface side and a lower layer on the non-skin contact surface side, and the upper layer is formed using heat-extensible fibers, and the heat-extensible fibers It has a fiber joined portion where the intersections of the two are joined, and the lower layer does not contain heat-extensible fibers or contains heat-extensible fibers in a lower ratio than the upper layer, and the skin contact surface side of the upper layer has an uneven shape. And the interface between the upper layer and the lower layer has a fixed portion bonded to each other and a non-fixed portion in which the upper layer and the lower layer are detachably laminated, and the inter-fiber distance of the upper layer is The top sheet of the absorbent article is larger than the distance between the fibers in the lower layer.

  In the surface sheet of the absorbent article of the present invention, the liquid hardly remains in the surface sheet and the touch is good.

It is a top view which shows the state which looked at the surface sheet of the absorbent article of 1st Embodiment of this invention from the upper layer side. It is the II-II line partial expanded sectional view of FIG. It is a schematic diagram which shows the manufacturing method of the surface sheet shown in FIG. It is sectional drawing which shows the surface sheet of the absorbent article of other embodiment of this invention. It is sectional drawing which shows the surface sheet of the absorbent article of other embodiment of this invention. It is sectional drawing which shows the surface sheet of the absorbent article of other embodiment of this invention.

The present invention will be described below based on preferred embodiments with reference to the drawings.
FIG. 1 is a plan view illustrating a state in which a top sheet 10 (hereinafter, also referred to as a top sheet 10) of an absorbent article according to a first embodiment of the present invention is viewed from the upper layer 11 side.
The topsheet 10 of the first embodiment is a topsheet having a two-layer structure having an upper layer 11 on the skin contact surface side and a lower layer 12 on the non-skin contact surface side. That is, as shown in FIG. 2, the topsheet 10 has a two-layer structure in which an upper layer 11 and a lower layer 12 are laminated, and the topsheet 10 faces the upper layer 11 side toward the wearer's skin side, It is used by being incorporated in an absorbent article with the lower layer 12 side facing the absorber.

Further, as shown in FIG. 2, the interface between the upper layer 11 and the lower layer 12 has a fixed portion 13 bonded to each other, and a non-fixed portion 18 in which the upper layer 11 and the lower layer 12 are detachably stacked. ing.
In the present embodiment, the fixing portion 13 is formed by laminating a web or nonwoven fabric that is an original fabric of the upper layer 11 and a web or nonwoven fabric that is an original fabric of the lower layer 12, and the laminate is embossed with or without heat. It is formed by embossing such as ultrasonic embossing. The fixing portion 13 can be formed by joining the upper and lower layers 11 and 12 via an adhesive instead of embossing.

Moreover, as for the surface sheet 10, the skin contact surface side of the upper layer 11 has comprised uneven | corrugated shape.
If it demonstrates in detail, the adhering part 13 in the surface sheet 10 will have the recessed parts 14 and 15 in the upper layer 11 side and the lower layer 12 side, respectively, as shown in FIG. Further, the surface 10a on the upper layer 11 side has convex portions 16 between the concave portions 14, and the surface 10 of the topsheet 10 has an uneven shape on the surface 10a on the upper layer 11 side. Since the surface 10a on the upper layer 11 side of the topsheet 10 has an uneven shape, the contact area between the topsheet 10 and the wearer's skin is reduced when the topsheet 10 is incorporated into an absorbent article. Thus, stuffiness and rash are effectively prevented.

The concave portions 14 and the convex portions 16 are alternately arranged in one direction (X direction in FIG. 1) of the topsheet 10. Moreover, the recessed part 14 and the convex part 16 are alternately arrange | positioned also in the direction (Y direction in FIG. 1) orthogonal to the said one direction of the surface sheet 10. FIG.
As shown in FIG. 1, the topsheet 10 has a first fixing line 13 a and a second fixing line 13 b that are inclined in opposite directions with respect to the X direction as the fixing portion 13. Each of the first fixing line 13a and the second fixing line 13b is formed in parallel with each other, and each has an area where the interval between the adjacent fixing lines is wide and a place where the interval is narrow. Yes.
On the skin contact surface side and the non-skin contact surface side of each of the first fixed line 13a and the second fixed line 13b, groove-shaped recesses 14 and 15 are formed so as to extend along the fixed lines. As shown in FIG. 1, the first fixed line 13a and the second fixed line 13b intersect in a lattice shape.
Further, the groove-like recesses 14 and 15 extending along the first fixing line 13a and the groove-like recesses 14 and 15 extending along the second fixing line 13b also intersect in the same grid pattern as the fixing lines 13a and 13b. In addition, on the upper layer 11 side (skin contact surface side) of the topsheet 10, three types of convex portions 16a, 16b, and 16c having different sizes and heights are formed. Both the convex portion 16a and the convex portion 16b have a rhombus shape in plan view, and the convex portion 16a has a larger area and a higher height D1 than the convex portion 16b. The convex portion 16c has a parallelogram shape in plan view, and has an intermediate area and height between the convex portion 16a and the convex portion 16b.

  Further, the interface between the upper layer 11 and the lower layer 12 has a non-fixed portion 18 in which the upper layer 11 and the lower layer 12 are detachably laminated between the fixed portions 13 and 13 in the planar direction of the topsheet 10. The upper layer 11 and the lower layer 12 in the non-adhered portion 18 are in contact with each other, but are not joined, and only fibers that are in contact with each other at the boundary between the upper layer 11 and the lower layer 12 in the non-adhered portion 18. A fusion bond is formed. This is because the fibers in each of the upper layer 11 and the lower layer 12 are not only crossed and fused in the plane direction but also crossed and fused in the thickness direction, and therefore cannot be separated into layers within each layer. Since the upper layer 11 and the lower layer 12 are made into a web or a nonwoven fabric by basically different processes, the fibers of each layer enter beyond the boundary and the fibers hardly cross and fuse in the thickness direction and are strong at the boundary. This is because it is difficult to form a crossed or fused state.

The upper layer 11 of the topsheet 10 is formed using heat-extensible fibers. Moreover, the upper layer 11 has the fiber junction part 17 to which the intersection of heat | fever extensible fibers was joined.
A heat-extensible fiber is a fiber whose length is extended by heating, and is a fiber that extends at a temperature of 90 ° C. or higher, preferably 110 ° C. to 130 ° C.
Examples of the heat-extensible fibers include fibers that change in the crystalline state of the resin due to heating, or fibers that have been crimped and have an apparent length that is released by crimping. The heat-extensible fiber in the present invention is a fiber having a fiber space larger than that of a non-extendable fiber as a result of the fiber being stretched by heat treatment during the production of the nonwoven fabric or after the nonwoven fabric is formed. In the comparison of non-extensible fibers and non-stretchable fibers using a core-sheath structure fiber (fiber thickness after heat treatment: 2 to 5 dtex, fiber length: 51 mm, elongation rate: 10%) using polypropylene, measurement of the interfiber distance described later The distance calculated by the method increases the inter-fiber distance of the nonwoven fabric by stretchable fibers of about 5 to 20 μm.
A preferred heat-extensible fiber has a first resin component having an orientation index of 20 to 80% (more preferably 40 to 70%), a melting point or a softening point lower than the melting point of the first resin component, and an orientation index. Is composed of 10 to 80% (more preferably 20 to 60%) of the second resin component, and the second resin component is present continuously in the length direction at least part of the fiber surface (hereinafter referred to as a composite fiber) These fibers are referred to as heat-extensible composite fibers), and fibers in which heat fusion occurs during heat extension are preferred.

  Below, the preferable manufacturing method of the surface sheet 10 using this heat | fever extensible composite fiber is demonstrated, referring FIG.

  First, a web 12A serving as a raw fabric of the lower layer 12 is produced using a predetermined web forming means (not shown). The web 12A does not contain a heat-extensible composite fiber or other heat-extensible fibers, or contains a heat-extensible composite fiber or other heat-extensible fibers in a lower ratio than the upper layer. Examples of the web forming means include (a) a card method in which short fibers are opened using a card machine, and (b) a method in which melt-spun continuous filaments are directly pulled by air soccer and deposited on a net (spunbond). And (c) a known method such as a method (air array method) in which short fibers are transported in an air stream and deposited on a net.

Separately from the web 12 </ b> A for the lower layer 12, a web 11 </ b> A serving as a raw fabric of the upper layer 11 is produced using a predetermined web forming means (not shown). The web 11A includes a heat-extensible composite fiber or is made of a heat-extensible composite fiber. Examples of the web forming means include (a) a card method in which short fibers are opened using a card machine, and (b) a method in which melt-spun continuous filaments are directly pulled by air soccer and deposited on a net (spunbond). And (c) a known method such as a method (air array method) in which short fibers are transported in an air stream and deposited on a net.
When a material in which fibers are oriented in one direction, such as a tow which is a bundle of long fibers spread as a raw material of the upper layer 11 in a direction orthogonal to the long fibers, the degree of freedom of each fiber is Since the individual fibers are individually elongated, it is difficult to form a fiber bonded portion in which the intersections of the fibers are bonded, and the upper layer 11 is greatly separated from the lower layer 12 so that there is a cavity between the two layers 11 and 2. Easy to do.
By using the web 11 </ b> A as described above as the raw material of the upper layer 11, the convex portion 16 can be formed by the upper layer 11 while maintaining contact or proximity between the upper layer 11 and the lower layer 12.

  Then, the web 12 </ b> A for the lower layer 12 and the web 11 </ b> A for the upper layer 11 are overlapped and introduced into the heat embossing device 21. And in the heat embossing apparatus 21, heat embossing is integrally performed to both the webs 12A and 11A of the piled-up state. The heat embossing device 21 includes a pair of rolls 22 and 23. The roll 22 is a smooth roll having a smooth peripheral surface. On the other hand, the roll 23 is an engraving roll in which a convex portion having a shape corresponding to the fixing portion 13 is formed on the peripheral surface thereof. Each roll 22, 23 can be heated to a predetermined temperature.

The heat embossing is performed at a temperature at which the components in the web 12A and / or the web 11A are melted and the web 12A and the web 11A are heat-sealed. The processing temperature for heat embossing is preferably higher than the melting point of the low melting point component and lower than the melting point of the high melting point component in the heat-extensible composite fiber in the web 11A. Moreover, it is preferable to carry out at the temperature below the elongation start temperature of a heat | fever extensible fiber.
By heat embossing, the web 12 </ b> A and the web 11 </ b> A are fixed in a non-peelable manner to form a fixed portion 13, and a laminated nonwoven fabric 24 in which the upper and lower layers 11 and 12 are joined at the fixed portion 13 is obtained.

  And the laminated nonwoven fabric 24 in which the adhering part 13 was formed is conveyed to the hot air spraying device 25. In the hot air blowing device 25, the laminated nonwoven fabric 24 is subjected to air through processing. The hot air blowing device 25 is configured such that hot air heated to a predetermined temperature penetrates the laminated nonwoven fabric 24.

  The air-through process is performed at a temperature at which the heat-extensible conjugate fiber in the laminated nonwoven fabric 24 is elongated by heating. And it is performed at the temperature at which the intersection of the heat-extensible composite fibers in a free state existing in the portion other than the fixing portion 13 in the laminated nonwoven fabric 24 is thermally fused. However, it is preferable that the temperature is lower than the melting point of the high melting point component of the heat-extensible conjugate fiber.

By such an air-through process, the heat-extensible conjugate fiber included in the upper layer 11 extends at a portion other than the fixing portion 13. Since a part of the thermally stretchable conjugate fiber is fixed by the fixing part 13, it is a part between the fixing parts 13 that extends. Since a part of the heat-extensible conjugate fiber is fixed by the fixing portion 13, the stretched portion of the stretched thermally-extensible conjugate fiber loses its place in the plane direction of the laminated nonwoven fabric 24, and the thickness of the nonwoven fabric 24. Move in the direction. Thereby, the convex part 11 is formed between the adhering parts 13 in the upper layer 11.
Further, the intersections of the heat-extensible conjugate fibers existing between the fixing portions 13 are joined by heat fusion by air-through processing, and the fiber joining portions 17 are formed in a three-dimensionally dispersed state.

Moreover, since the downward movement of the heat-extensible conjugate fiber existing in the upper layer 11 adjacent to the lower layer 12 is largely restricted by the lower layer 12 that is not substantially elongated even by air-through processing, There is almost no phenomenon of entanglement with the fibers in the lower layer 12. Therefore, in the plane direction of the obtained surface sheet 10, the non-adhered portion 18 in which the upper layer 11 and the lower layer 12 are detachably laminated between the adhering portions 13 where the upper layer 11 and the lower layer 12 are bonded together so as not to be peeled off. Is formed. Furthermore, at the boundary between the upper layer, which is a web made of heat-extensible fibers, and the lower layer, which is a web or non-woven fabric that is not heat-extensible, the contact (crossing) position of the fibers changes due to stretching, so that it is sufficient for fusing the fibers together. Resin is hardly obtained at the contact portion, fusion itself is unlikely to occur, and the fusion strength tends to be low.
Thus, the target surface sheet 10 is obtained.

  As is clear from the above description, in the topsheet 10, the lower layer 12 is not contracted and the expansion is suppressed from the upper layer, while the heat-extensible composite fiber in the upper layer 11 is elongated, and the above-described convex portion 16 is formed so as to protrude in the upper layer direction, so that a fiber having a rough structure can be formed without using fibers thicker than the fibers of the lower layer 12 as the fibers constituting the upper layer 11 or heat-shrinking the lower layer 12. 16, and a fiber density gradient can be formed between the upper layer 11 and the lower layer 12. Therefore, in the surface sheet 10 of the present embodiment, the convex portion 16 is soft, the touch of the surface 10a on the upper layer 11 side is good, the drawability of the liquid from the upper layer 11 to the lower layer 12, and further below from the lower layer 12 It is excellent in the liquid transferability to the absorber (not shown) arranged in the.

  Furthermore, the topsheet 10 of the present embodiment has a non-adhered portion 18 in which the upper layer 11 and the lower layer 12 are detachably laminated between the adhering portions 13 and 13 in the planar direction, and therefore, between the upper layer and the lower layer. In this case, an interlayer boundary is formed, and the extension direction of the heat stretch fiber of the upper layer can be directed to the upper layer side. For this reason, it is preferable that the lower layer is made of a non-woven fabric in advance or that the web is not deformed in the plane direction and the thickness direction by the extensible fibers. In addition, if the lower layer is arranged to such an extent that the deformation by the heat-extensible fibers does not occur regardless of whether it is a nonwoven fabric or a web, the network structure by the fibers is disturbed, and the liquid permeability due to the formation of large voids is reduced. Has the effect of increasing.

  From the viewpoint of making it difficult for the liquid in the surface sheet 10 to remain, the average diameter of the fibers constituting the upper layer 11 after the fiber extension and the average diameter of the fibers constituting the lower layer 12 after the fiber extension are substantially the same or lower layer. 11 is preferably larger, and the distance between fibers (gap between fibers) is preferably larger in the upper layer 11 than in the lower layer 12.

  The average diameter is substantially the same when comparing the average fiber diameter measured by the following method, the ratio of the average diameter of the fibers constituting the upper layer 11 and the average diameter of the fibers constituting the lower layer 12 (the former / The latter) is 0.9 to 1.1.

<Measuring method of average diameter of constituent fibers>
The average diameter of the constituent fibers was measured by one of two methods that differ depending on the cross-sectional shape of the fibers. For the measurement, “Carry Scope JCM-5100” manufactured by JEOL Ltd. was used.
First, the cross-sectional contour shape of the constituent fibers was confirmed at a magnification of 500 to 1000 times. At this time, not only the cross-sectional contour of the fiber, but also the core-sheath structure fiber / single fiber, the core component / sheath component area ratio, and the type of fiber (differentiated by thickness, shape, etc.) are grasped. (Measure 5 to 10 different cross sections)
The first method is a measurement method in the case where the cross section is formed only with a fiber having a circular cross section, and an arbitrary 20 except for a fiber fusion part from 200-500 times plane enlarged images of each of five upper and lower layers. The thickness of the fibers of the book is measured and averaged to obtain the “average diameter of the constituent fibers”.
The second method is a measurement method in the case where a fiber whose cross section is not circular is included, and uses an enlarged image with a magnification of 500 to 1000 times for measuring the cross-sectional contour shape of the fiber. The cross-sectional area of one fiber cut at approximately 90 degrees is calculated by a means capable of calculating the area such as an image analyzer, and the area is regarded as a circle and the diameter is set as the fiber diameter. Image observation with an electron microscope is performed until the cross-sectional observation result of such a single fiber reaches 50, and the average value of the 50 is defined as “average diameter of constituent fibers”.
As an image analysis apparatus for measuring the area of the cross section of the fiber, for example, image analysis software NEW QUABE (ver. 4.20) manufactured by NEXTUS can be used.

  The interfiber distance (gap between fibers) is the difference between the interfiber distance of the upper layer 11 and the interfiber distance of the lower layer 12 (the former-the latter) when the interfiber distance measured by the following method is compared. The thickness is preferably 0 μm or more from the viewpoint of liquid movement, and is preferably 0 to 50 μm from the viewpoint of the strength and feel of the topsheet.

<Measurement method of distance between fibers>
The following Wrotnowski equation was used.

Here, the packing density and fineness (denier) of the fiber are measured as follows.
The fiber packing density is measured by the following procedure.
The area ratio of the fixed part is calculated from the planar image on the upper layer side of the top sheet. In the calculation, it is preferable to measure about 20 fixed portions at a time. Next, the rectangular topsheet whose length and weight in the vertical direction and the horizontal direction are measured is separated into an upper layer and a lower layer, and the weights of the upper layer and the lower layer are measured. At this time, if the fixed part can be removed, the fixed part is removed, and if it cannot be removed, it is determined whether the upper part or the lower layer contains the fixed part. The basis weight (g / m ² ) is calculated from the weight of each of the topsheet, the upper layer and the lower layer, and the lengths in the vertical and horizontal directions. In the calculation, the area factor of the fixed portion is corrected. (For example, when there is no fixing part on the upper layer side and there is a fixing part on the lower layer side, the area of the fixing part is calculated from the area of the surface sheet obtained by multiplying the length in the vertical direction and the horizontal direction, When calculating the basis weight of the upper layer, use the area obtained by subtracting the fixed part from the area of the top sheet, and when calculating the basis weight of the lower layer, subtract the weight of the fixed part from the lower layer weight. Use the subtracted area.) Then measure the cross-sectional area of the topsheet. An electron microscope is preferably used for measurement, but an optical device such as Keyence's digital high scope VH8000 may be used. The enlarged image includes the top portion of the convex portion from the fixed portion. When the convex portion has a different height, each cross-sectional image is observed. The packing density can be calculated by dividing the basis weight (g / m ² ) by the height (m). However, as in the present invention, the substantial basis weight is the same from the fixed part to the convex part, and the height is high. Is changed, the average height is calculated from the cross-sectional areas of each of the upper layer and the lower layer, and this average height is used as the “height” at the time of calculation to obtain “fiber packing density”. The cross-sectional area is obtained by measuring the portion excluding the fixed portion with an image analysis apparatus and dividing the length between the fixed portions excluding the fixed portion from the cross-sectional area.
The fineness (denier) specifies the resin used for the fiber by DSC when the upper and lower fibers are each composed of one type of fiber, and the specific gravity (substantially density) and the cross-sectional area of the fiber The weight when the length of the fiber is 9000 m is denier. In a composite fiber such as a core-sheath structure, since the sheath component is a fusion component, the resin is similarly specified using DSC, and the average specific gravity is calculated from the cross-section during magnified observation. When a plurality of fibers are used, the average specific gravity is calculated from the blending ratio of the fibers by Method 2 in measuring the average diameter. (In the present invention, the specific gravity of the high density polyethylene is 0.94, polypropylene 0.96, polyester 1.36)

The topsheet 10 of the present embodiment manufactured by the above-described manufacturing method pressurizes the web 11A, 12A with the web 11A side for the upper layer 11 positioned on the engraving roll 23 side and air pressure. At the time of through processing, the upper layer 11 is greatly expanded as compared with the lower layer 12 due to the expansion of the heat-extensible fibers, and is swollen to the one surface 10a side. Therefore, the fixing portion 13 is on each of the upper layer 11 side and the lower layer 12 side. The ratio (D1 / D2) of the depth D1 of the concave portion 14 on the upper layer 11 side and the depth D2 of the concave portion on the lower layer 12 side (D1 / D2) is the basis weight T1 of the upper layer fiber and the basis weight of the lower layer fiber. It is larger than the ratio of the amount T2 (T1 / T2).
Unlike the case where the lower layer 12 is shrunk using heat-shrinkable fibers, in addition to the fiber density of the lower layer 12 being not so high, the bottom of the recess 14 and the absorber disposed further below the lower layer 12 Since the distance between them is small, it is more effectively prevented that the liquid remains in the top sheet 10.

  The ratio (D1 / D2) is preferably 2 or more, and more preferably 2.5 or more. The ratio (T1 / T2) is preferably 1 to 5, and more preferably 1.5 to 4.

<Measuring method of the depths D1 and D2>
Next, an example of a method for measuring the depths D1 and D2 will be described below.
When the fixing part 13 is linear, it is a line connecting adjacent intersections, and when the fixing part 13 is dotted, it is a line connecting adjacent points, and the cut section is observed with an electron microscope. The maximum value of the height difference between the bottom portion and the bottom portion of the concave portion 15 and the upper layer 11 is defined as the depth D1. Further, the maximum value of the height difference between the position where the bottom of the recess 14 and the bottom of the recess 15 are equally divided and the lower layer 12 is defined as a depth D2.

  Moreover, since the recessed part is formed in the upper layer 11 side of the laminated nonwoven fabric 24 by the heat embossing process, and the air through process was performed with respect to the laminated nonwoven fabric 24, the amount of swelling of the protruding part 16 can be effectively increased. Can do.

  As described above, the web 11A for the upper layer 11 includes a heat-extensible composite fiber or is formed of a heat-extensible composite fiber. When the web 11A for the upper layer 11 includes a heat-extensible fiber, the other fibers included in the web 11A include a thermoplastic resin having a melting point higher than the heat-extension temperature of the heat-extensible composite fiber. Examples thereof include fibers made of resin and fibers that do not inherently have heat-fusibility (for example, natural fibers such as cotton and pulp, rayon and acetate fibers). The other fibers are preferably contained in the web 11A for the upper layer 11 or the upper layer 11 in an amount of 0 to 40% by weight, more preferably 5 to 15% by weight. On the other hand, when the heat-extensible conjugate fiber is contained in the web 11A or the upper layer 11 for the upper layer 11 in an amount of 50 to 100% by weight, particularly 70 to 95% by weight, a three-dimensional uneven shape can be effectively formed. To preferred. The web 11A for the upper layer 11 or the upper layer 11 is particularly preferably made of a heat-extensible conjugate fiber from the viewpoint that a three-dimensional uneven shape can be more effectively formed.

  Preferred examples of the heat-extensible conjugate fiber are described in paragraphs [0024] to [0040] of Patent Document 3. Further, the heat stretchable composite fiber has a stretch rate of 5 to 40, particularly 10 to 30% at a temperature higher by 10 ° C. than the melting point or softening point of the second resin component, so that the uneven shape is remarkably formed. To preferred.

As the fiber constituting the lower layer web 12A or the lower layer 12, a core-sheath structure type (including side-by-side type) composite fiber using polypropylene or polyester as the core component and polyethylene as the sheath component is preferably used. The web 12A or the lower layer 12 for the lower layer may contain a heat-extensible fiber such as a heat-extensible composite fiber, but the content of the heat-extensible fiber in the web 12A or the lower layer 12 is 30% by weight. It is preferably at most 10% by weight, more preferably at most 5% by weight. Most preferably, the lower layer web 12A or the lower layer 12 does not contain a heat-extensible fiber such as a heat-extensible composite fiber.
In addition, the lower layer web 12A or the lower layer 12 preferably does not contain heat-shrinkable fibers that heat-shrink when heated, or even if it does contain heat-shrinkable fibers in the air-through process. By not causing the web 12A or the lower layer 12 to be thermally contracted with heat-shrinkable fibers, the fiber density of the upper layer 11 and the lower layer 12 can be reduced, and the surface sheet 10 having a small liquid remaining amount as a whole can be obtained.

  Next, another embodiment of the present invention will be described. In other embodiments, differences from the above-described first embodiment will be mainly described, and description of similar points will be omitted. About the same point, the explanation about the 1st embodiment is applied suitably.

As shown in FIG. 4, the top sheet 10 </ b> A of the absorbent article according to the second embodiment has an adhering portion 13 </ b> A in which only fibers located in the vicinity of the lower layer 12 in the upper layer 11 are thermally fused to the lower layer 12. ing. The fibers located on the surface of the top sheet 10A in the upper layer 11 are joined at the fiber joining portion 17 where the intersections of the fibers are joined by air-through processing, but are not fixed to the fixing portion 13A. It covers the part 13A. In the method for manufacturing the topsheet 10, the topsheet 10A is formed by laminating the web for the upper layer 11 and the web for the lower layer 12 and then positioning the engraving roll on the web side for the lower layer 12 and smoothing the engraving roll. It can be manufactured by maintaining a relatively large clearance with the roll, performing heat embossing, and then performing air-through processing in the same manner as described above. The top sheet 10A of the absorbent article according to the second embodiment is such that the upper layer 11 including the heat-extensible fibers is stretched in a state where the portion located in the vicinity of the lower layer 12 is fixed to the fixing portion 13A. A convex portion 16 is formed on the surface.
In the top sheet 10A of the absorbent article of the second embodiment, the fixing part 13A is difficult to see from the surface on the upper layer 11 side, and is excellent in concealing properties such as the color of the liquid when the liquid is absorbed by the fixing part 13A. Yes.

As shown in FIG. 5, the top sheet 10 </ b> B of the absorbent article according to the third embodiment has a through hole 19 that penetrates the upper layer 11 and the lower layer 12, and the upper layer 11 is formed on the inner peripheral surface of the through hole 19. A fixed portion 10B is formed in which the lower layer 12 is fixed by melting or solidifying one or both of the constituent fibers. In the method for manufacturing the topsheet 10 described above, the topsheet 10B is formed on both the superposed webs instead of integrally embossing the web for the top layer 11 and the web for the bottom layer 12 with each other. Then, the heated pin is penetrated, and then air-through processing is performed in the same manner as in the method for manufacturing the top sheet 10 described above.
When the fixing portion 10B is formed on the inner peripheral surface of the through hole 19, the liquid penetrates the surface sheet 10B through the through hole 19 and the area of the fixing portion 10B in plan view can be reduced. It is even more excellent in preventing residue.

  As shown in FIG. 6, the top sheet 10 </ b> C of the absorbent article according to the fourth embodiment has the upper layer 11 and the lower layer 12 bonded together in the plane direction so as not to be peeled in the same manner as the top sheet 10 of the first embodiment. Although the fixing portion 13 is provided, the portions 16 d and 16 d of the convex portion 16 formed by the upper layer 11 protrude on the fixing portion 13, and a portion of the fixing portion 13 is part of the convex portion 16. Covered by the portions 16d and 16d. The topsheet 10C can be manufactured in the same manner as in the above-described method for manufacturing the topsheet 10, except that the web 11A for the upper layer 11 has a larger basis weight. According to the topsheet 10C, the fixing portion 13 where the liquid tends to remain is covered with the portions 16d and 16d of the convex portion 16 and is difficult to see from the surface 10a side on the upper layer 11 side of the topsheet 10D. 13 is excellent in concealing the remaining liquid such as menstrual blood.

The top sheet of the absorbent article of the present invention is used as the top sheet of the absorbent article.
The absorbent article is mainly used for absorbing and holding excretory body fluids such as urine and menstrual blood. Absorbent articles include, for example, disposable diapers, sanitary napkins, incontinence pads, and the like, but are not limited to these, and widely include articles used to absorb liquid discharged from the human body.
The absorbent article typically includes a top sheet, a back sheet, and a liquid-retaining absorbent body disposed between both sheets. Absorbent articles generally have a skin contact surface that contacts the wearer's skin when worn and a non-skin contact surface directed to the opposite side (usually clothing side such as shorts). The back sheet is disposed on the skin contact surface side, and the back sheet is disposed on the non-skin contact surface side. The surface sheet in the present invention is arranged with the upper layer side facing the wearer's skin.
As the absorber and the back sheet, materials usually used in the technical field can be used without particular limitation. For example, as the absorbent body, a fiber assembly made of a fiber material such as pulp fiber or a fiber assembly in which an absorbent polymer is held can be coated with a covering sheet such as tissue paper or nonwoven fabric. As the back sheet, a liquid-impermeable or water-repellent sheet such as a thermoplastic resin film or a laminate of the film and a nonwoven fabric can be used. The back sheet may have water vapor permeability. The absorbent article may further include various members according to specific uses of the absorbent article. Such members are known to those skilled in the art. For example, when applying an absorbent article to a disposable diaper or a sanitary napkin, a pair or two or more pairs of three-dimensional guards can be disposed on the left and right sides of the topsheet.

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 first embodiment, heat embossing, which is embossing with heat, is used to form the fixing part 13, but instead, the fixing part is formed by embossing without heat or ultrasonic embossing. You can also Alternatively, the fixing portion can be formed by an adhesive.
Moreover, instead of using the webs 11A and 12A as the original fabrics of the upper layer 11 and the lower layer 12, a nonwoven fabric may be used for one or both of the top sheet and the lower layer 12, respectively. In particular, the lower layer side is preferably made of a nonwoven fabric from the viewpoint of flatness of the lower layer (contactability with the absorber) and ease of formation of the convex shape on the upper layer side by further suppressing the entry of the upper layer fibers. Also, the melting point of the fibers used in the lower layer is set higher than that of the fibers used in the upper layer. Specifically, the core fiber melting point of the lower layer fiber or the lower layer fiber is higher than the core component melting point of the upper layer fiber. And the point of the ease of the heat processing at the time of absorbent article formation is preferable.

Further, instead of forming the linear fixing portion 13 in a pattern as shown in FIG. 1, the linear fixing portion 13 may be formed in another pattern. The linear adhering portion 13 has a line width of, for example, 0.1 to 3.0 mm.
Moreover, it may replace with the linear fixing | fixed part 13, and may form the fixing | fixed part 13 in the shape of a dot on a surface sheet. In this case, the area of the fixing portion 13 is preferably about 1 to 10 mm ² , and the shape of the fixing portion 13 is an arbitrary shape such as a circle, a triangle, a rectangle, a rhombus, other polygons, an L shape, a heart shape, or the like. It can also be a combination of these two types.
In addition, from the viewpoint of forming a three-dimensional uneven shape, it is necessary that some heat-extensible conjugate fiber that is not fixed to the fixing portion 13 exists, and the embossing rate is 1 to 20%, more preferably 2. It is preferable that it is 10% from the point which can form a three-dimensional uneven | corrugated shape effectively.

  The description omitted in one embodiment described above and the requirements of only one embodiment can be applied to other embodiments as appropriate, and the requirements in each embodiment can be appropriately changed between the embodiments. Can be substituted.

10, 10A to 10C Absorbent article surface sheet 11 Upper layer 11A Upper layer web 12 Lower layer 12A Lower layer web 13, 13A, 13B Adhering portion 14 Upper layer side concave portion 15 Lower layer side concave portion 16 Convex portion 17 Fiber bonding portion 18 Non-fixed part 19 Through-hole 21 Heat embossing device 22, 23 Roll 24 Laminated nonwoven fabric 25 Hot air spraying device

Claims (4)

It is a two-layered surface sheet having an upper layer on the skin contact surface side and a lower layer on the non-skin contact surface side,
The upper layer is formed using heat-extensible fibers, and has a fiber joined portion in which the intersections of the heat-extensible fibers are joined by heat fusion , and the lower layer does not contain heat-extensible fibers or Containing a heat extensible fiber in a lower proportion than the upper layer,
The skin contact surface side of the upper layer has an uneven shape,
The interface between the upper layer and the lower layer has a fixed portion bonded to each other, and a non-fixed portion in which the upper layer and the lower layer are detachably laminated,
In the non-fixed part, a fusion part between fibers only in contact with the interface between the upper layer and the lower layer is formed,
The top sheet of an absorbent article, wherein the distance between the fibers in the upper layer is larger than the distance between the fibers in the lower layer.   The said lower layer is a surface sheet of the absorbent article of Claim 1 currently formed from the fiber which does not have heat extensibility.   The surface sheet of an absorbent article according to claim 1 or 2, wherein an average diameter of fibers constituting the upper layer and an average diameter of fibers constituting the lower layer are substantially the same or larger in the lower layer. The upper layer, the surface sheet of an absorbent article according to any one of claims 1 to 3 covering a portion of the plan view the anchoring portion.

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