JP4343992B2 - Absorbent article surface sheet - Google Patents

Description

  The present invention relates to a surface sheet used for absorbent articles such as sanitary napkins and disposable diapers.

  Conventionally, as a surface sheet of an absorbent article such as a disposable diaper or a sanitary napkin, a surface that is embossed on a surface that comes into contact with a wearer's skin to form irregularities is known. According to the surface sheet having unevenness, the contact area with the skin of the wearer is reduced due to the presence of the unevenness, so that it is possible to reduce stickiness and stuffiness. Moreover, when the surface sheet having such irregularities is formed from a sheet made of a fiber material, the density gradient of the fibers constituting the sheet between the embossed part formed by embossing and the non-embossed part Is formed. In the embossed portion having a high fiber density, the capillary force works more strongly than in the non-embossed portion having a low fiber density, so that the excreted liquid easily migrates from the non-embossed portion to the embossed portion in the surface sheet. As a result, the liquid can be smoothly transferred in the thickness direction of the top sheet.

As such a surface sheet, for example, Patent Document 1 discloses a surface sheet in which circular embossed portions are formed in a dotted pattern and a staggered pattern.
Further, in Patent Document 2, a rectangular embossed portion is provided in a predetermined pattern on a stretched plastic sheet to hold the embossed portion in a stretched state, thereby releasing the stretched state of the plastic sheet. Thus, a surface sheet of an absorbent article is proposed in which a region other than the embossed portion is contracted to form irregularities on the plastic sheet.

JP-A-10-272152 JP 2002-160293 A

  However, in the surface sheet provided with the circular embossed portion described in Patent Document 1, the density gradient of the constituent fibers is mainly formed from the central portion of the region surrounded by the embossed portion toward each embossed portion. It is. Therefore, in order to perform the liquid diffusion and the liquid thickness transition more smoothly, a surface sheet provided with density gradients of constituent fibers in more directions has been demanded. The embossed part in the surface sheet described in Patent Document 2 is provided in the plastic sheet, and the formation of the embossed part does not affect the liquid transfer in the surface sheet.

  Accordingly, an object of the present invention is to provide a surface sheet of an absorbent article in which density gradients of constituent fibers are provided in multiple directions, and liquid diffusion and liquid thickness transition are quickly performed. .

  The present invention is a top sheet of an absorbent article made of a fiber material and formed with a number of embossed portions, and has an upper layer and a lower layer containing heat-shrinkable fibers that are heat-shrinked, the upper layer and the A lower layer is laminated to each other and joined at the embossed portion, and a large number of convex portions are formed on the surface on the upper layer side, and the convex portion is an abbreviation of an area surrounded by three or more embossed portions. The embossed contour, which has an apex at the center, is a curved or curved shape on the convex side of the embossed portion, and the embossed contour is around the convex portion. At least three so as to surround the convex portion, and the embossed portion surrounding the convex portion, and between the adjacent embossed portions, the density of the topsheet is at the top of the convex portion. Higher than the density of the surface sheet in the embossed portion. The lower intermediate part is formed, and the convex part achieves the above-mentioned object by providing a surface sheet of the absorbent article surrounded by the embossed part and the intermediate part (hereinafter referred to as the following). The first invention refers to this invention).

  The present invention is a top sheet of an absorbent article made of a fiber material and formed with a large number of embossed portions, each of the large number of embossed portions being at least two long axes passing through the center of gravity in plan view The two adjacent embossed portions that are at the shortest distance exist on a substantially extended line in the major axis direction, and the density of the topsheet between the two adjacent embossed portions is the embossed portion. By providing a surface sheet of an absorbent article that is higher than the density of the surface sheet in the central portion of the enclosed region, the above object has been achieved (hereinafter referred to as the second invention, Refers to the invention).

  Further, the present invention includes a top sheet of the absorbent article, a liquid-impermeable or water-repellent back sheet, and a liquid-retaining absorbent disposed between the two sheets. A sheet | seat is related with the absorbent article arrange | positioned so that the surface of the said upper layer side may contact | abut a wearer's skin. The top sheet is liquid permeable, and is preferably suitable as a top material for a sanitary napkin that quickly sucks viscous liquid such as menstrual blood.

According to the surface sheet of the absorbent article of the present invention, since the density gradient of the constituent fibers is provided in multiple directions, the liquid diffusion and the liquid migration in the liquid thickness direction are performed quickly. This reduces liquid residue and stickiness, and further improves the dry feeling for the wearer.
Furthermore, skin troubles caused by rubbing due to a decrease in the contact area with the skin of the wearer during wearing are reduced.

Hereinafter, the surface sheet of the absorbent article of the present invention will be described based on preferred embodiments with reference to the drawings.
As shown in FIGS. 1 to 5, the top sheet 1 of the first embodiment is a top sheet made of a fiber material and formed with a large number of embossed portions 4. The top sheet 1 of the first embodiment is an embodiment of the first invention and the second invention.

As shown in FIGS. 4 to 6, the topsheet 1 of the first embodiment has an upper layer 2 and a lower layer 3 containing heat-shrinkable fibers that have been heat-shrinked. The upper layer 2 and the lower layer 3 are laminated together. Further, the upper layer 2 and the lower layer 3 are joined by a large number of embossed portions 4.
As shown in FIG. 4, the surface sheet 1 has a large number of convex portions 6 formed on the surface on the upper layer 2 side. As shown in FIG. 7, each convex portion 6 has a vertex 61 at a substantially central portion of the region 7 surrounded by the four embossed portions 4 </ b> A to 4 </ b> D. The emboss contour 43 that is the contour on the convex portion 6 side of each of the embossed portions 4 </ b> A to 4 </ b> D has a shape bent or curved toward the convex portion 6 in the plan view of the topsheet 1. More specifically, the embossed contour 43 is composed of two straight portions 44 and 45, and the two straight portions 44 and 45 form an angle of 90 degrees, and the end portions are joined to each other.

Four embossed contours 43 are formed around each convex portion 6 so as to surround the convex portion 6. And it is embossed part 4A-4D surrounding the convex part 6, Comprising: Between adjacent embossed parts, ie, between embossed part 4A and embossed part 4B, between embossed part 4B and embossed part 4C, and embossed part 4C The density of the surface sheet 1 is higher than the density of the surface sheet 1 at the apex 61 of the convex part 6 between the embossed part 4D and between the embossed part 4D and the embossed part 4A. Intermediate portions 62A to 62D that are lower than the density of the surface sheet are formed. The convex portion 6 is surrounded by the embossed portions 4A to 4D and the intermediate portions 62A to 62D.
Further, in the embossed contour 43 composed of the two straight portions 44 and 45, the density of the intermediate portion 62 is improved by the fact that the one straight portions 44 and 45 of the adjacent embossed portions are located on the same straight line L4. It is preferable from the point.

As shown in FIG. 3, each of the numerous embossed portions 4 in the top sheet 1 of the first embodiment has at least two long axes L <b> 1 and L <b> 2 that pass through the center of gravity 41 in plan view. And the two adjacent embossed parts 4 and 4 in the shortest distance exist on the substantially extended line of the major axis L (L1, L2) direction.
Each embossed portion in the first embodiment has a cross shape in plan view. More specifically, two vertically long bar-shaped bodies have shapes that intersect each other at the center. In the present embodiment, the center line extending in the longitudinal direction of each rod-shaped body is the major axes L1 and L2, and the intersection of the major axes L1 and L2 is the center of gravity 41.

  As shown in FIGS. 4 and 5, the top sheet 1 of the first embodiment is formed by laminating two fiber layers, an upper layer 2 and a lower layer 3. The upper layer 2 and the lower layer 3 are joined to each other at a large number of embossed portions 4 by pressure bonding using embossing. The upper layer 2 is recessed at the embossed portion 4 to form a number of recessed portions 5. A non-embossed portion between the concave portions 5, that is, a region surrounded by the embossed portion 4 forms a convex portion 6. As a result, the upper layer 2 is formed with a large number of uneven portions over the entire area. And also as the whole surface sheet 1, many uneven | corrugated | grooved parts are formed over the whole region.

  As shown in FIG. 3, the embossed portion 4 has a shape having two long axes L1 and L2 passing through the center of gravity 41 and two short axes S1 and S2. The two long axes L1 and L2 are equal in length, and the two long axes L1 and L2 are orthogonal to each other at their midpoints. The lengths of the two short axes S1 and S2 are also equal, and they are orthogonal to each other at the midpoint. That is, the embossed portion 4 has a cross shape, and is formed in a state where the cross shape is inclined by 45 degrees with respect to the machine direction (MD direction) and its orthogonal direction (CD direction). The portion of the cross shape that protrudes in the major axis direction has substantially the same width up to the tip 42.

  Further, two adjacent embossed portions 4 and 4 at the shortest distance are symmetrical with a perpendicular bisector P2 of a line P1 connecting the centroids 41 and 41 of the two embossed portions 4 and 4, as shown in FIG. It is arranged in line symmetry as an axis. That is, the front ends 42 of the long axes L of the adjacent embossed portions 4 and 4 are arranged so as to face each other. In the first embodiment, each of the four tips 42 in one embossed portion 4 is disposed to face the tips 42 of adjacent embossed portions 4 at the shortest distance, and as shown in FIG. A number of embossed portions 4 are provided over the entire area in the plane direction.

  Thus, each embossed portion 4 has two long axes L1 and L2 passing through the center of gravity 41, and two adjacent embossed portions 4 and 4 at the shortest distance are in the direction of the long axis L. By being arranged so as to be substantially on the extended line, the surface sheet 1 is formed with a density gradient of the constituent fibers in multiple directions, and the surface sheet 1 has liquid diffusion and liquid permeability in the thickness direction. improves.

  In addition, the shortest distance between the intermediate portions 62A to 62D (see FIG. 7) located between adjacent embossed portions of the embossed portions 4A to 4D surrounding the convex portion 6, particularly the region 62 sandwiched between adjacent long axes. In the cross section in the thickness direction of the topsheet 1 along the line ZZ connecting the adjacent embossed portions, an intermediate convex portion 63 whose surface is convex upward (on the wearer's skin side) is formed. ing. The intermediate convex portion 63 has a height T1 '(see FIG. 6) from the surface of the embossed portion that is lower than a height T2' (see FIG. 4) of the central convex portion 6 from the surface of the embossed portion.

  Due to the presence of the intermediate convex portion 63, the density of the fibers decreases from the apex 61 of the convex portion 6 toward the top of the intermediate convex portion 63, and is positioned at both ends of the intermediate convex portion from the apex of the intermediate convex portion 63. Even toward the embossed vicinity 64, a gradient is formed. As a result, the liquid drawn from the convex part is drawn toward the embossed part, and also has an intermediate convex part between the adjacent embossed and embossed parts, so that the pulling force is further improved than before. Not only the liquid permeability but also the liquid diffusibility is further improved.

  Moreover, in the surface sheet 1 of this embodiment, the convex part 6 has the part 65 (refer FIG. 7) which faced the embossing outlines 44 and 45 harder than the other site | part of this convex part 6. FIG. Therefore, the shape retention property of the convex part 6 formed by embossing is improved, a cushioning feeling is imparted to the topsheet 1, and a wearer with an excellent wearing feeling is given.

  In the embossed part 4, as shown in FIG. 4, the constituent fibers of the top sheet 1 are consolidated, and the thickness of the top sheet 1 is thinner than the convex part 6 that is a non-embossed part. That is, the fiber density in the embossed part 4 is higher than the fiber density in the convex part 6. Depending on the embossing conditions, the fibers may be melted and solidified to form a film.

  In the first embodiment, as shown in FIG. 3, the convex portion 6 is formed so as to be surrounded by the four embossed portions 4. As shown in FIGS. 2 and 4, the thickness of the upper layer 2 is the thickest at the vertex 61 where the distance from the four embossed portions 4 in the convex portion 6 is the longest, and from the vertex 61 to the embossed portion 4. It is getting thinner gradually. Therefore, the fiber density is lowest at the apex 61 and gradually increases from the apex 61 toward the embossed portion 4. 3 shows four examples of the embossed portions surrounding the convex portion 6, the number of embossed portions surrounding the convex portion 6 is three or more, and may be five or six.

  An intermediate convex portion 63 is formed in the region 62 between the adjacent embossed portions 4 and 4 at the shortest distance, but the interval W1 (see FIG. 3) between the adjacent embossed portions 4 and 4 is narrowed. Thus, the region 62 is strongly affected by embossing. Therefore, the thickness T1 of the upper layer 2 in the region 62 between the adjacent embossed portions 4 and 4 at the shortest distance is thinner than the thickness T2 of the upper layer 2 at the vertex 61. As a result, as shown in FIG. 5, the thickness of the upper layer 2 is gradually reduced toward the region 62 between the adjacent embossed portions 4 and 4 at the shortest distance from the vertex 61, and the fiber density is the vertex 61. Gradually increases toward the region 62 between the adjacent embossed portions 4 and 4 at the shortest distance. The intermediate convex portion 63 may be convex between adjacent long axes of adjacent embosses, and the convex portion may be a ridge-shaped ridge or may have a top at an intermediate point while having the ridge. The ridge-shaped ridges may exist in parallel between the major axes of the embossment, or may exist in a direction crossing the major axes and orthogonal to the major axis.

Thus, in the surface sheet 1 of the first embodiment, as shown in FIGS. 4 and 5, the density gradient of the constituent fibers is formed from the vertex 61 toward the embossed portion 4, and the shortest distance from the vertex 61. A density gradient is also formed toward the region 62 between the adjacent embossed portions 4 and 4.
Capillary force acts more strongly in the high density portion where the gaps between the constituent fibers are small than in the low density portion where the gaps between the constituent fibers are large. Therefore, the body fluid excreted by forming a density gradient on the topsheet 1 Is drawn from the low density portion in the top sheet 1 to the high density portion and moves quickly.

The density of the embossed portion 4 is preferably 1 to 32 pieces / cm ² , more preferably 2 to 16 pieces / cm ² , from the viewpoint of enhancing the liquid diffusibility in the top sheet 1 and maintaining good touch. Further, the interval W1 (see FIG. 3) between the two adjacent embossed portions 4 and 4 at the shortest distance is preferably 0.5 to 5.0 mm from the viewpoint of strengthening the density gradient of the constituent fibers in the topsheet 1. More preferably, it is 1.0-3.0 mm. When the interval W1 between the adjacent embossed portions 4 and 4 at the shortest distance is less than 0.5 mm, particularly when the adjacent embossed portions 4 and 4 are connected to form a lattice-like embossed portion, one convex portion There is a possibility that the diffusion of the liquid in the planar direction from 6 to the other convex part 6 is hindered.

Also, the area of one of the embossed portion 4, preferably 1.0 to 10 mm ^2, more preferably 1.7~5.0mm ^2.
The ratio (W2 / W3) between the length W2 of the major axis L and the length W3 of the minor axis S is preferably 2 to 10, from the viewpoint of enhancing the liquid diffusibility in the surface sheet 1 and maintaining good touch. More preferably, it is 2-6.

  The density of the topsheet 1 between the two adjacent embossed portions 4 and 4 is higher than the density of the topsheet 1 in the central portion of the region surrounded by the embossed portion 4 from the viewpoint of enhancing the dry feeling during mounting. Preferably it is. The ratio (ρ2 / ρ1) of the density ρ2 of the topsheet 1 between two adjacent embossed sections 4 and 4 to the density ρ1 of the topsheet 1 in the center of the region surrounded by the embossed section 4 is preferably 1. It is 5 times or more, more preferably 1.7 times or more.

The ratio of the density of the topsheet can be measured using either one of the two methods (1) and (2) described below.
(1) When the basis weight of the surface sheet is substantially uniform (uniform) (or when it can be determined that the surface sheet is substantially uniform), the thickness of the cut surface of the surface sheet is measured.
(2) When the basis weight of the top sheet is non-uniform (or can be determined to be non-uniform), the average distance between fibers on the cut surface of the top sheet is measured.

  Here, the determination as to whether the basis weight of the topsheet is substantially uniform is performed as follows. When the surface sheet was taken out from 10 or more absorbent articles and each basis weight was measured, the triple value (3σ) of the standard deviation σ was within 10% of the average μ, and fiber unevenness was seen in appearance. If not, it is determined to be substantially uniform. However, it is preferable to make a comprehensive judgment in consideration of various factors such as the composition being different in a minute region.

First, the method (1) will be described.
The cut portion of the top sheet in plan view is a straight portion (thickest here) passing through the central portion of the region surrounded by the embossed portion 4 and the embossed portion 4, and the embossed portion 4 and the embossed portion 4. Select at least two of the linear parts at the shortest distance. At this time, in order to prevent the thickness from being restored by cutting as much as possible, a sample is prepared so as to have both ends of each measurement part (maximum thickness part in each cutting part) of the cut sample and other embossed parts 4 To do.

The cross section is measured using a JEOL electron microscope JCM-5100 under the conditions of a sputtering time of 30 seconds (Pt) and an acceleration voltage of 10 KV. Whether at least one of the embossed parts 4 at both ends of the measuring part is photographed, Alternatively, a situation where the embossed portion 4 is understood by combining a plurality of images is measured, and the thickness of each measuring portion is measured from the captured image. Note that the image measurement may be performed using either a printed matter or a PC screen.
In the method (1), the thickness of the center part of the region surrounded by the embossed part 4 is divided by the thickness between the embossed parts 4 and 4 to obtain the density ratio.

Next, the method (2) will be described.
The cross section is measured in the same manner as in the method (1). In addition to the measurement performed in the method (1), a cross section with an enlargement magnification of 500 to 1000 is also photographed. Using the image analysis device (NEWQBE ver. 4.20 manufactured by NEXUS) in the region where the number of fibers is 3 to 7 in the width direction (planar direction) at the target measurement site of each of the magnified images, Find the distance between the centers of gravity.
In the above measurement, the measurement is performed almost entirely in the thickness direction, and the closest distance between the centers of gravity is not caused to overlap. Moreover, about a cross section, it measures at least 3 places, Preferably 5 places, More preferably, 10 places, The average value is used.
In the method (2), the distance between the nearest centroids in the center of the region surrounded by the embossed part 4 is divided by the distance between the nearest centroids between the embossed parts 4 and 4 to obtain a density ratio.

  In the topsheet 1 of the first embodiment, each embossed portion 4 has two long axes L1 and L2 passing through the center of gravity 41, and two adjacent embossed portions 4 and 4 at the shortest distance are By being arranged so as to be on a substantially extended line in the major axis L direction, the surface sheet 1 is formed with a density gradient of the constituent fibers in multiple directions, and the liquid of the surface sheet 1 is diffused in the thickness direction. Improves liquid permeability.

  Specifically, the body fluid excreted on the top sheet 1 is strongly drawn from the apex 61 toward the four embossed portions 4 surrounding the convex portion 6, and between the adjacent embossed portions 4 and 4 at the shortest distance. It is also drawn toward the region 62. As a result, body fluid diffuses in multiple directions from the apex 61 to the direction of the embossed part 4 and the direction of the region 62 between the embossed parts 4, 4. The transition to is made promptly. Moreover, since the excreted body fluid quickly moves through the surface sheet 1 and quickly moves to the absorber or the like disposed on the lower surface side of the surface sheet 1, the liquid residue in the surface sheet 1 is reduced, and further The whiteness of the surface of the absorbent article using the top sheet 1 can be maintained.

In place of the embossed portion 4 in the first embodiment, if the circular embossed portion 4 is provided and the interval between the adjacent embossed portions 4 and 4 is narrowly formed, the embossed portion 4 occupying the entire surface sheet 1 area. The ratio of the area increases, and the permeability of the liquid in the top sheet 1 decreases and the touch also decreases.
That is, according to the topsheet 1 of the absorbent article of the first embodiment, the density gradient of the topsheet 1 can be efficiently designed by the embossed portion 4 having a smaller area, so that the area compressed by the embossing can be reduced, The touch of the surface sheet 1 can be improved.
Moreover, it has the effect which raises the formation of the protrusion of the convex part 6 in the surface sheet 1 by designing the shape of the embossed part 4 to have a biaxial long axis.

  As shown in FIG. 3, two adjacent embossed portions 4, 4 at the shortest distance are intermediate convex portions 63 at the center between the embossed portions 4, 4 of the region 62 between the embossed portions 4, 4. Is formed. Therefore, the density gradient of the topsheet 1 is uniformly formed from the apex 61 in multiple directions in the plane direction, and the excreted body fluid can be more dispersed and diffused.

  Next, other embodiments of the surface sheet of the absorbent article of the present invention will be described. Other embodiments will be described with a focus on differences from the first embodiment described above, and the same points will be denoted by the same reference numerals and description thereof will be omitted. For the points that are not particularly described, the description of the first embodiment is applied as appropriate.

FIGS. 8A to 8C show the shape and arrangement pattern of the embossed portions 4 in the second to fourth embodiments of the top sheet of the absorbent article of the present invention, respectively. Each of the embossed portions 4 in the second to fourth embodiments has at least two long axes L passing through the center of gravity 41. Further, the two adjacent embossed portions 4 and 4 at the shortest distance exist on a substantially extended line of the embossed portion 4 in the major axis L direction. Further, the embossed portion 4 in the second to fourth embodiments is similar to the embossed portion 4 in the first embodiment in that two adjacent embossed portions 4, 4 at the shortest distance are two embossed portions 4, 4. The lines are arranged symmetrically about the perpendicular bisector of the line connecting the centroids 41 as the symmetry axis.
Even with the topsheet 1 of the second to fourth embodiments having the embossed portions 4 having such shapes and arrangement patterns, the same effects as the topsheet 1 of the first embodiment described above are exhibited.

  The embossed portion 4 in the second embodiment shown in FIG. 8A is different in shape from the embossed portion 4 in the first embodiment shown in FIG. 3, but is arranged in the same arrangement pattern.

  The shape of the embossed portion 4 in the second embodiment is, as shown in FIG. 8A, the width of the portion protruding in the long axis direction of the cross shape compared to the shape of the embossed portion 4 in the first embodiment. However, it gradually spreads toward the tip 42. Moreover, the front-end | tip 42 is formed in the curve curved convexly toward the front-end | tip 42 of the adjacent embossing part 4 in the shortest distance. Thus, it is preferable that the long-axis tip 42 is formed in a curved line in that the upper layer 2 is difficult to be cut during embossing.

  As shown in FIG. 8B, the embossed portion 4 in the third embodiment has a Y shape, and has three long axes L <b> 1, L <b> 2, and L <b> 3 that pass through the center of gravity 41. The angle formed by intersecting the long axes L1, L2, and L3 is 120 degrees. The lengths of the three major axes L1, L2, and L3 are equal. Each embossed part 4 is arranged so that the long-axis tips 42 of two adjacent embossed parts 4, 4 at the shortest distance face each other, and the convex part 6 surrounded by the six embossed parts 4 is 6. It is arranged to form a square.

  As shown in FIG. 8C, the embossed portion 4 in the fourth embodiment has an asterisk (*) shape in which six lines extend radially with an angle of 60 degrees, and a center of gravity 41 is formed. It has three major axes L1, L2, and L3 that pass through. The angle formed by intersecting the long axes L1, L2, and L3 is 120 degrees. The lengths of the three major axes L1, L2, and L3 are equal. Each embossed part 4 is arranged so that the long-axis tips 42 of two adjacent embossed parts 4, 4 at the shortest distance face each other, and the convex part 6 surrounded by the three embossed parts 4 is positive. They are arranged to form a triangle.

FIG. 9 shows a form in which four embossed portions 4a having an elliptical shape are formed such that one end in the major axis direction of the elliptical shape faces the center and the four embossed portions 4a are close to each other. .
In this way, when the plurality of embossed portions 4a are formed in a state of being very close to each other, and the aggregate of the plurality of embossed portions 4a substantially functions as one embossed portion, the set of the plurality of embossed portions 4a The body is treated as one embossed part 4. That is, the four embossed parts 4a shown in FIG. 9 regard the aggregate as one cross-shaped embossed part 4.

FIG. 10 shows a macroscopic cross-shaped embossed portion 4 formed by a plurality of dot-shaped embossed portions 4b gathering so as to form a cross shape.
Thus, when the aggregate of a plurality of embossed parts 4b functions as one embossed part substantially, the aggregate of a plurality of embossed parts 4b shall be handled as one embossed part 4. That is, the plurality of embossed portions 4 b shown in FIG. 10 regards the aggregate as one cross-shaped embossed portion 4.

Next, a preferable method for producing the top sheet of the absorbent article of the present invention will be described.
The surface sheet 1 of the absorbent article of the present invention is, for example, a non-heat-shrinkable fiber material or an upper layer 2 made of fibers having a higher heat shrinkage temperature than the lower layer fibers and before shrinkage having a heat shrinkage temperature higher than that of the upper layer fibers. When the lower layer 3 made of a heat-shrinkable fiber material is partially or wholly fused in a predetermined pattern by embossing such as heat, heat is applied to cause the lower layer 3 to thermally shrink in the horizontal direction. Because heat shrinkage does not occur or thermal shrinkage is lower than the lower layer, and the upper and lower layers are embossed and integrated, when the lower layer shrinks, the upper layer tries to shrink, but distortion occurs, This distortion appears as a raised ridge in the upper layer. More specifically, for example, heat fusion by heat embossing is performed by, for example, forming an embossed surface (a peripheral surface of an embossing roll, etc.) in which a large number of embossed pins having a predetermined shape are arranged in a predetermined pattern, The process is performed by melting the constituent fibers of the upper layer 2 and / or the lower layer 3 at the portion that is pressed against the upper layer 2 side of the laminate and is thermally pressed by each pin. The convex portion 6 formed by the upper layer 2 may have a portion protruding so as to cover the embossed portion.

The heat shrinkage of the lower layer 3 is, for example, the lower layer 3 is made of heat-shrinkable fibers, or the heat-shrinkable fibers are included in the lower layer 3 and the upper layer 2 and the lower layer 3 are heat-sealed simultaneously or both. After heat-sealing, the lower layer 3 is heated. Thus, by thermally contracting the lower layer 3 in the horizontal direction, the protuberance-forming property of the convex portions formed on the upper layer 2 is enhanced, and the topsheet 1 that is more bulky and feels better can be obtained.
When the surface sheet 1 is configured by laminating the two fiber layers in this way, from the viewpoint of improving the liquid permeability in the thickness direction of the surface sheet 1, between the two fiber layers. Preferably, no interface is formed.

As the upper layer 2, for example, a web formed by a card method or a bulky nonwoven fabric is preferably used. The web formed by the card method is a fiber assembly in a state before being made into a nonwoven fabric. That is, a fiber assembly in which fibers are in an extremely loose entanglement state after being subjected to a post-treatment applied to a card web used for manufacturing a nonwoven fabric, for example, a heat-sealing treatment by an air-through method or a calendar method. It is the body. When the web formed by the card method is used as the upper layer 2, the fibers in the upper layer 2 are heat-sealed simultaneously with or after the upper layer 2 and the lower layer 3 are bonded. Moreover, as a bulky nonwoven fabric, an air through nonwoven fabric, an airlaid nonwoven fabric, a resin bond nonwoven fabric, etc. are mentioned.
It is preferable that the constituent fibers of the upper layer 2 have substantially no heat shrinkability, or are not heat-shrinkable below the heat shrinkage temperature of the constituent fibers of the lower layer 3.
The basis weight of the upper layer 2, the soft aspects and topsheet 1 to form a sufficient density gradient from the viewpoint of good, preferably 10 to 50 g / m ^2, more preferably a 15 to 40 g / m ^2.

As the lower layer 3, a web formed by a card method or a nonwoven fabric having heat shrinkability can be used.
As the constituent fiber of the lower layer 3, one made of a thermoplastic polymer material and having heat shrinkability is preferably used. Examples of such fibers include latently crimpable fibers. The content ratio of the latent crimpable fiber in the lower layer 3 is preferably 40 to 100% by weight. The latent crimpable fiber can be handled in the same manner as a conventional nonwoven fabric fiber before being heated, and has a property that a helical crimp is developed and contracted by heating at a predetermined temperature. Fiber.

The latent crimpable fiber is composed of, for example, an eccentric core-sheath type or side-by-side type composite fiber composed of two types of thermoplastic polymer materials having different shrinkage rates. Examples thereof include those described in JP-A-9-296325 and Japanese Patent No. 2759331. The lower layer 3 can include such latent crimpable fibers, for example, and simultaneously with or after heat fusion with the upper layer 2, the crimps of the fibers can be expressed by heating to be contracted.
The basis weight of the lower layer 3 is preferably 10 to 50 g / m ² , more preferably 15 to 40 g / m ² .

The surface sheet 1 composed of the upper layer 2 and the lower layer 3 has a basis weight of preferably 20 to 100 g / m ² , more preferably 35 to 80 g / m ² .
Since the surface sheet 1 has a large number of irregularities, the sheet 1 is thick and bulky.

The surface sheet of the absorbent article of the present invention is not limited to the embodiment described above, and can be appropriately changed without departing from the spirit of the present invention.
For example, the top sheet 1 has a two-layer structure in the first to fourth embodiments, but may be composed of a single-layer fiber sheet. In this case, it is preferable to use a bulky fiber sheet. Moreover, although the heat shrinkable thing was used as the lower layer 3, you may use the sheet | seat which consists of a fiber which does not have heat shrinkability.
In the surface sheet 1 of the absorbent article of the present invention, the configurations of the embodiments described above can be combined as appropriate. For example, two or more embossed portions 4 having the shapes shown in FIGS. 3 and 6 to 9 may be used in combination.
Further, the shape of the embossed portion 4 is not limited to the shape described above.

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. In this invention, it is preferable that the surface sheet is distribute | arranged so that the surface of an upper layer side may contact | abut a 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.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further, this invention is not restrict | limited at all by the Example mentioned later.

(Example)
(1) Manufacture of the first layer A card having a basis weight of 22 g / m ^{2 by} a card method using a core-sheath type composite fiber [NBF (SH) (trade name), 2.2 dtex × 51 mm] manufactured by Daiwa Boseki Co., Ltd. as a raw material A web was produced and used as the first layer. The core-sheath type composite fiber has polyethylene terephthalate as a core component and polyethylene as a sheath component.
(2) Manufacture of the second layer A card having a basis weight of 22 g / m ² by a card method using a latent spiral crimped fiber [L (V) (trade name), 2.2 dtex × 51 mm] of Daiwa Boseki Co., Ltd. as a raw material A web was produced and used as the second layer.
(3) Production of three-dimensional sheet material The first layer and the second layer were overlapped and partially joined by an ultrasonic embossing method. The joining portion has a cross shape, and as shown in FIG. 3, two adjacent embossed portions at the shortest distance are arranged on a substantially extended line in the long axis direction of the cross shape so as to form a convex portion with four embosses. Pattern was formed. After joining both, hot air of 130 ° C. ± 10 ° C. is allowed to pass for 5 to 10 seconds to crimp the second layer of latent crimped fibers, shrink the second layer and project the first layer between the joints. The three-dimensional sheet material which protruded in the shape and has many convex parts was manufactured. The distance W1 between two adjacent embossed portions 4 and 4 at the shortest distance of the surface sheet after heat shrinkage is 1.6 mm, the length W2 of the cross-shaped major axis L is 2.8 mm, and the length of the minor axis S The length of the length W3 was 1.1 mm. Moreover, the density of the embossed part 4 was 6.86 pieces / cm ² .

(Comparative Example 1)
(1) Manufacture of the first layer A card having a basis weight of 22 g / m ^{2 by} a card method using a core-sheath type composite fiber [NBF (SH) (trade name), 2.2 dtex × 51 mm] manufactured by Daiwa Boseki Co., Ltd. as a raw material A web was produced and used as the first layer. The core-sheath type composite fiber has polyethylene terephthalate as a core component and polyethylene as a sheath component.
(2) Manufacture of the second layer A card having a basis weight of 22 g / m ² by a card method using a latent spiral crimped fiber [L (V) (trade name), 2.2 dtex × 51 mm] of Daiwa Boseki Co., Ltd. as a raw material A web was produced and used as the second layer.
(3) Production of three-dimensional sheet material The first layer and the second layer were overlapped and partially joined by an ultrasonic embossing method. The joint portion was circular, and a large number of pins were regularly arranged in the pattern shown in FIG. After joining both, hot air of 130 ° C. ± 10 ° C. is allowed to pass for 5 to 10 seconds to crimp the second layer of latent crimped fibers, shrink the second layer and project the first layer between the joints. The three-dimensional sheet material which protruded in the shape and has many convex parts was manufactured. The distance W1 between two adjacent embossed portions 4 and 4 at the shortest distance of the surface sheet after heat shrinkage was 2.2 mm, and the diameter W4 of the circular embossed portion was 2.0 mm. Moreover, the density of the embossed part 4 was 6.86 pieces / cm ² .

(Comparative Example 2)
(1) Manufacture of the first layer A card having a basis weight of 22 g / m ^{2 by} a card method using a core-sheath type composite fiber [NBF (SH) (trade name), 2.2 dtex × 51 mm] manufactured by Daiwa Boseki Co., Ltd. as a raw material A web was produced and used as the first layer. The core-sheath type composite fiber has polyethylene terephthalate as a core component and polyethylene as a sheath component.
(2) Manufacture of the second layer A card having a basis weight of 22 g / m ^{2 by} a card method using a core-sheath type composite fiber [NBF (SH) (trade name), 2.2 dtex × 51 mm] manufactured by Daiwa Boseki Co., Ltd. as a raw material A web was produced and used as the second layer. The core-sheath type composite fiber has polyethylene terephthalate as a core component and polyethylene as a sheath component.
(3) Production of three-dimensional sheet material The first layer and the second layer were overlapped and partially joined by an ultrasonic embossing method. The joint portion was arranged similarly to the pattern of FIG. After both were joined, similar to the sample preparation method described in the examples, hot air of 130 ° C. ± 10 ° C. was passed for 5 to 10 seconds to produce a sheet material having a large number of embossed portions. The distance W1 between two adjacent embossed portions 4 and 4 at the shortest distance of the top sheet is 2.1 mm, the length W2 of the cross-shaped major axis L is 2.8 mm, and the length W3 of the minor axis S The thickness was 1.1 mm. Moreover, the density of the embossed part 4 was 4.08 pieces / cm ² .

  For the surface sheets obtained in Examples and Comparative Examples 1 and 2, (1) the contact area with the skin, (2) the friction coefficient with the skin, and (3) the amount of residual wicking, the results are shown in Table 1. Indicated.

(1) Contact area with skin In order to evaluate the stickiness felt by the wearer when wearing a napkin and the quality of stuffiness, the contact area between the skin and the napkin surface was measured by the following method.
〔Measuring method〕
About each surface sheet of an Example and a comparative example, the contact area with skin was measured with the following method. A sample was cut into a size of 60 mm × 80 mm, a pressureless state and a transparent acrylic plate with a weight of 50 g were placed on the top, and a 250 g weight was further placed on the acrylic plate, and 6.25 gf / cm ² . With the load applied, the surface shape of each sample was measured using a high-accuracy shape measurement system KS-1100 manufactured by Keyence, and an image was captured. Analyzing the captured image using Keyence's shape analysis application KS-Analyzer, extracting the portion that changed in the thickness direction from a no-load state to a 6.25 gf / cm ² load, and binarized By processing, an image of a portion in contact with the skin at the time of wearing was obtained. This image was printed with a printer and loaded into a computer. For image capture, the center of the sample is used, and two [Sunlight SL-230K2; manufactured by LPL Co., Ltd.] are used as light sources, and a CCD camera (HV-37; manufactured by Hitachi Electronics Co., Ltd.). ) And a lens (Nikon Ai AF Nicol 24mmF2.8D) are connected by an F mount, an image is captured and processed using a Nexus NewQube (Ver. 4.22), and the contact area is measured. The “contact area ratio” was calculated by dividing by the area.

(2) Coefficient of friction with skin The coefficient of friction with skin was measured by the following method in order to evaluate the quality of the feeling of rubbing with the skin felt by the wearer when wearing the napkin.
〔Measuring method〕
About each surface sheet of an Example and a comparative example, the friction coefficient with skin was measured with the following method. Cut the sample surface sheet into a size of 50 mm x 50 mm and use a double-sided paper tape on a hooked weight (weight 211 g, length 63 mm x width 63 mm x thickness 7 mm) so that the adhesive surface of the sample is the back side Glued to. The weight to which the sample was adhered was allowed to stand on the acrylic plate so that the surface of the sample was on the lower side, a wire was attached to the hook, and attached to a tensile tester Tensilon RTC-1210A manufactured by Orientec via a pulley. The weight to which the sample was bonded was pulled at a pulling speed of 200 mm / min and slid horizontally on the acrylic plate. The average value of the load of the recorded chart was made into frictional force, and the friction coefficient was computed from the weight of the weight which adhered the sample.

(3) Liquid absorption rate In order to evaluate the quality of the dry feeling felt by the wearer when wearing the napkin, the liquid absorption rate for absorbing liquid from the skin was measured for the surface sheets obtained in the examples and comparative examples by the following method. did.
〔Measuring method〕
The absorption rate of each surface sheet of the examples and comparative examples is an apparatus generally known as an apparatus for performing the DW method according to the DW method generally used for measuring the absorption rate of the absorbing polymer ( Demand Wettability Tester). Specifically, the surface sheet sample is a size of 60 mm × 80 mm on a sample table (30 mmφ, a table in which No. 2 filter paper is placed on a glass filter No. 1) on which the liquid level of simulated menstrual blood is set at an equal water level. cut out the installation to the evaluation sample obtained by bonding by means of hot melt adhesive on each absorbent sheet (made of pulp 200 g / m ² and the water-absorbing polymer 50 g / m ²⁾ surface sheet becomes lower did. The water absorption amount at the time of installation was set to 0, and the liquid absorption amount after 240 seconds and after 600 seconds (this liquid absorption amount is measured by a burette scale indicating the amount of decrease in the water level of simulated menstrual blood). The value of the liquid absorption obtained was defined as the liquid absorption speed per predetermined time.

According to the results in Table 1, in the example, the convex portion in the upper layer on the skin contact surface side is raised and a convex portion having a relatively sharp shape is formed toward the skin surface. In the case of contact, it is considered that the contact area with the skin can be reduced by touching the skin from the convex top and relatively less crushing of the top, and as a result, the friction coefficient with the skin can be kept low. In Comparative Examples 1 and 2, the convex portion is comparatively gentle, and even if it is slightly crushed, the contact area with the skin becomes relatively wide, and it can be considered that the friction coefficient with the skin is high.
Moreover, in the liquid absorptivity speed | rate, a liquid absorption occurs rapidly in an Example and the improvement effect of the stickiness with respect to skin is acquired.

  As can be seen from the results of the above measurements of Examples and Comparative Examples, the surface sheet of the present invention can quickly absorb excretion such as menstrual blood and urine containing a stimulating substance on the skin without leaving it on the surface. Maintains the structure, reduces the contact area with the skin, reduces the frictional force with the skin, has high air permeability, prevents skin stuffiness, and has surface characteristics with little frictional irritation to the skin In addition to providing a comfortable wearing feeling to the wearer, it is difficult to cause skin problems such as itchiness and rash.

FIG. 1 is a perspective view showing a first embodiment of a top sheet of an absorbent article of the present invention. FIG. 2 is a plan view of the top sheet of the absorbent article shown in FIG. FIG. 3 is an enlarged view showing the shape and arrangement pattern of the embossed portion in the top sheet of the absorbent article shown in FIG. FIG. 4 is a cross-sectional view taken along line XX shown in FIG. 5 is a cross-sectional view taken along line YY shown in FIG. FIG. 6 is a cross-sectional view taken along the line ZZ shown in FIG. FIG. 7 is an enlarged schematic plan view showing details of the shape and the like of the embossed portion of the topsheet shown in FIG. FIG. 8A to FIG. 8C are plan views showing the shape and arrangement pattern of the embossed portions in the second to fourth embodiments of the top sheet of the absorbent article of the present invention (corresponding to FIG. 3). It is. FIG. 9 is a view showing a modification of the shape of the embossed portion in the top sheet of the absorbent article of the present invention. FIG. 10 is a view showing a modification of the shape of the embossed portion in the top sheet of the absorbent article of the present invention. FIG. 11 is a plan view showing the shape and arrangement pattern of embossed portions in the top sheet of Comparative Example 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Top sheet 2 Upper layer 3 Lower layer 4 Embossed part 41 Gravity center 42 Tip 43 Emboss outline 44,45 Straight line part which comprises emboss outline 5 Concave part 6 Convex part 61 Vertex 62A-62D Intermediate part 63 Intermediate convex part 7 Surrounded by the embossed part Region L (L1-L3) Long axis S (S1, S2) Short axis

Claims (6)

A surface sheet of an absorbent article made of a fibrous material and formed with a number of embossed parts,
It has an upper layer and a lower layer containing a heat-shrinkable heat-shrinkable fiber, and the upper layer and the lower layer are laminated to each other and bonded at the embossed portion,
Numerous convex portion is formed on a surface of said upper, each number of the convex portion has an apex at substantially central portion of the region surrounded by the three or more of the embossed portions, of the embossed portion The embossed contour which is the contour on the convex side has a shape bent or curved on the opposite side to the convex portion, and at least three embossed contours are formed around the convex portion so as to surround the convex portion. Has been
A embossed portion surrounding the convex portion, between embossed portions adjacent, the density of the topsheet is higher rather than the density of the surface sheet at the vertex of the convex portion forms a convex surface of the upper An intermediate convex part is formed,
Each of the plurality of embossed portions has a cross shape in plan view and has four tips, and the adjacent embossed portions at the shortest distance are arranged so that the one tip faces each other. And
The interval between two adjacent embossed portions is 0.5 to 5 mm,
The height of the intermediate protrusion is lower than the height of the protrusion,
The said convex part is the surface sheet of an absorbent article surrounded by the said embossed part and the said intermediate | middle convex part.   The surface sheet of an absorbent article according to claim 1, wherein the heat-shrinkable fibers are crimpable fibers that develop a helical crimp upon heat treatment.   The topsheet of an absorbent article according to claim 1 or 2, wherein the embossed contour is composed of two straight portions, and one straight portion of each of the adjacent embossed portions is located on the same straight line. The top sheet of the absorbent article according to any one of claims 1 to 3 , wherein a portion of the convex portion facing the embossed contour is harder than other portions of the convex portion. Topsheet of an absorbent article according to any one of claims 1-4 density of the embossed portion is 1 to 32 pieces / cm ^2. A top sheet of the absorbent article according to any one of claims 1 to 5 , a liquid-impermeable or water-repellent back sheet, and a liquid-retaining absorbent disposed between the two sheets. The absorbent sheet is arranged such that the surface on the upper layer side is in contact with the skin of the wearer.

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