JP5184966B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article such as a cage sheet (panty liner) and a sanitary napkin.

  Conventionally, bodily fluid absorbent articles such as cage sheets and sanitary napkins are composed of a liquid-permeable top sheet, a liquid-impervious back sheet, and a liquid-absorbent core interposed between these two sheets. . As the surface sheet, a nonwoven fabric or a perforated synthetic resin film is used. And as a surface sheet, the proposal which improves absorptivity is made by using what gave various shapes, such as a hole sheet which has a liquid introduction pipe, and a sheet which has a slotted structure (for example, patent documents). 1 and 2).

JP 2007-175515 A JP-A-9-299402

  Patent Document 1 discloses, as a surface sheet, a plurality of protrusions that protrude upward from the liquid-absorbent core and extend in the lateral direction of the article and are spaced apart by a given dimension in the longitudinal direction of the article, and the protrusions. There is described a body fluid treatment article that employs a surface member having a plurality of recesses extending in the transverse direction therebetween and a large number of apertures penetrating in the thickness direction and allowing body fluid to pass therethrough. However, the bodily fluid treatment article described in Patent Document 1 has a configuration in which the ridges extend from the inner surface side of the surface member to the central portion in the thickness direction, and a triangle in which a part of the sheet is raised and the inner surface is fixed. Due to the structure formation (see description of FIG. 5 of Patent Document 1 and description of [0041], etc.), the fiber orientation in the layer on the skin contact surface side of the surface member tends to be oriented in the thickness direction of the layer, The diffusibility of the liquid in the width direction of the article is high, and in particular, a bodily fluid having a relatively high viscosity such as menstrual blood tends to enter the top of the convex part in contact with the wearer's skin when worn or the vicinity thereof. For this reason, the body fluid treatment article described in Patent Document 1 has a problem that stickiness is likely to occur.

  In Patent Document 2, a surface layer made of a nonwoven fabric having alternating ridges and grooves extending in the longitudinal direction of an article and having openings formed in the grooves, and disposed between the surface layer and the back sheet. An absorbent article having a liquid filtration layer is described. However, since the ridge groove structure in the absorbent article described in Patent Document 2 is formed by curving a nonwoven fabric sheet having a substantially uniform thickness into a wave shape, the inside of the ridge portion is hollow. For this reason, in the absorbent article described in Patent Document 2, although the surface layer having the ridge groove structure is designed to maintain its shape even by body pressure or the like, a gap is easily generated between the surface layer and the liquid filtration layer. Liquid easily enters the hollow structure of the buttocks. For this reason, there existed a problem that a surface layer was easy to get wet and stickiness was easy to generate | occur | produce.

  An object of the present invention is to provide an absorbent article that does not feel sticky and can be used comfortably.

  The present invention provides a vertically long absorbent article provided with a surface sheet on the skin contact surface side and a back sheet on the non-skin contact surface side, wherein the surface sheet has a flange and a groove extending in the longitudinal direction of the absorbent article. And the heel portion is made of a non-woven fabric having a substantially larger amount of fibers than the groove portion, and is arranged closest to the surface layer and the back sheet constituting the skin contact surface. The front surface layer is lower in hydrophilicity than the back surface layer, is curved convexly toward the skin contact surface side in the heel portion, and has a skin contact in the groove portion. The object is achieved by providing an absorbent article that is concavely curved on the contact surface side and in which the constituent fibers of the back surface layer are oriented mainly in the thickness direction of the back surface layer.

  The absorbent article of the present invention has excellent liquid absorbency and can absorb and hold highly viscous body fluids such as menstrual blood so as not to cause discomfort to the wearer. The feeling of use is good.

  Hereinafter, the absorptive article of the present invention is explained based on the desirable embodiment with reference to drawings. FIG. 1 shows a plan view of an origami sheet, which is a first embodiment of the absorbent article of the present invention, as viewed from the top sheet side. FIG. 2 is a diagram schematically showing a cross section taken along line II in FIG.

  As shown in FIG. 1, the cage sheet 1 according to the first embodiment has a vertically long shape in plan view, and the central portion in the longitudinal direction is bound inward as a whole. The cage sheet 1 includes a top sheet 10 positioned on the skin contact surface side and a back sheet 11 positioned on the non-skin contact surface side. The top sheet 10 and the back sheet 11 are joined to each other by heat treatment at their outer peripheral edge portions, thereby forming a seal portion 15. The seal portion 15 is formed over the entire outer peripheral edge of the cage sheet 1. An adhesive part (not shown) for fixing the cage sheet 1 to the underwear is provided on the non-skin contact surface (outer surface of the back sheet 11) in the center region in the width direction of the cage sheet 1. It is formed to extend in the longitudinal direction.

  In this specification, the “longitudinal direction” is a direction along the long sides of the absorbent article or various members constituting the absorbent article (vertical direction in FIG. 1), and the “width direction” is orthogonal to the longitudinal direction. Direction (left and right direction in FIG. 1). Further, the “skin contact surface” is a surface directed to the skin side of the wearer when wearing the absorbent article in the absorbent article or various members constituting the absorbent article, and the “non-skin contact surface” It is a surface directed to the underwear side (opposite to the wearer's skin side) when the absorbent article is worn in the absorbent article or various members constituting the absorbent article.

  FIG. 3 is a perspective view of the top sheet 10 in FIGS. 1 and 2. 4 is a cross-sectional view taken along line II-II in FIG. In FIG. 3, the direction indicated by Y is the longitudinal direction of the raised sheet 1, and the direction indicated by X is the width direction of the raised sheet 1. The topsheet 10 of the first embodiment has a first surface 10a and a second surface 10b opposite to the first surface 10a. The 1st surface 10a is a surface which faces a wearer's skin side, when the surface sheet 10 is integrated in absorbent articles, such as a cage sheet, a sanitary napkin, and a disposable diaper. The second surface 10b is a surface facing the back sheet 11 side. The top sheet 10 is made of a non-woven fabric that alternately has ridges 20 and grooves 30 extending in the longitudinal direction Y of the cage sheet 1, and the ridges 20 have substantially more fiber than the grooves 30. The eaves part 20 and the groove part 30 are alternately arranged over the direction X orthogonal to the direction Y in which they extend. Further, the top sheet 10 has a multilayer structure including a top layer 10 </ b> A constituting a skin contact surface and a back layer 10 </ b> B disposed closest to the back sheet 11. As shown in FIGS. 3 and 4, the top sheet 10 in the first embodiment includes an intermediate layer 10 </ b> C disposed between the top layer 10 </ b> A and the back layer 10 </ b> B, and has a three-layer structure as a whole. .

  The collar portion 20 is filled with the constituent fibers of the topsheet 10. That is, there is no cavity in the collar portion 20. Similarly, the groove part 30 is filled with the constituent fibers of the topsheet 10. However, the fiber amount of the flange portion 20 is different from the fiber amount of the groove portion 30, and the fiber amount of the flange portion 20 is substantially larger than that of the groove portion 30.

  The flange portion 20 is configured from a relatively thick portion of the topsheet 10, and the groove portion 30 is configured from a relatively thin portion of the topsheet 10. As a result, the substantial thickness of the flange portion 20 is larger than the thickness of the groove portion 30. Here, the substantial thickness means not the length (apparent thickness) from the back surface of the top sheet 10 to each uppermost part, but the length of the portion where the fibers of the top sheet 10 are present.

  As shown in FIG. 4, in the cross section in the direction orthogonal to the extending direction (the direction indicated by X in the drawing), the flange portion 20 has a smooth curve that is convex upward on the first surface 10 a side. It has a contour to draw. The first surface 10a side of the flange portion 20 is raised higher than the second surface 10b side, and this is periodically continuous. Thus, the first surface 10a side has a waveform shape along the X direction. Therefore, when the 1st surface 10a side of the surface sheet 10 touches a wearer's skin, the top part of the collar part 20 and the area | region of the vicinity will contact partly, and the stickiness by the stuffiness resulting from a full surface contact Feeling and irritation caused by rubbing are reduced. Moreover, it becomes difficult for the liquid excreted from the wearer to adhere to the wearer's skin.

  As shown in FIG. 4, the flange portion 20 has a top portion 21 on the first surface 10 a side in the cross section in the X direction, and the substantial thickness is the largest at this portion. Then, with respect to the X direction, the substantial thickness gradually decreases as the distance from the top portion 21 increases. Therefore, when the surface sheet 10 is seen along the X direction, the substantial thickness is periodically changed. Although not shown in the drawing, the collar portion 20 has substantially the same thickness at the top portion 21 at any position in the extending direction (the direction perpendicular to the paper surface in FIG. 4). In the topsheet 10 of the first embodiment, there is no clear boundary between the flange portion 20 and the groove portion 30, and in general, the portion having the smallest substantial thickness located between the two top portions 21 adjacent to each other in the X direction. And the site | part of the vicinity becomes the groove part 30. FIG. When the boundary between the flange portion 20 and the groove portion 30 is clearly defined, the position of the apparent thickness at the top portion 21 of the flange portion 20 is defined as the boundary portion between the flange portion 20 and the groove portion 30.

  The apparent thickness of the collar portion 20 is preferably 0.3 to 5 mm, more preferably 0.5 to 2.5 mm, from the viewpoint of improving the touch of the topsheet 10. The height difference D (see FIG. 4) between the flange portion 20 and the groove portion 30 is preferably 0.1 to 3 mm from the viewpoint of enhancing the cushioning property and air permeability of the topsheet 10 and controlling the diffusion of the liquid. 3-2 mm is more preferable. The thickness and height difference D of the flange part 20 and the groove part 30 are measured by using a microscope VH-8000 (manufactured by Keyence) and observing the cross section of the topsheet 10 at 50 to 200 times. The cross section is obtained by cutting the top sheet 10 using a feather razor (part number FAS-10, manufactured by Feather Safety Razor Co., Ltd.).

  The width of the heel portion 20 in the X direction of the topsheet 10 is preferably 1 to 10 mm, and more preferably 2 to 5 mm, from the viewpoint of touch and absorbency. From the same viewpoint, the width of the groove 30 in the X direction of the topsheet 10 is preferably 0.5 to 7 mm, and preferably 1 to 3 mm. In 1st Embodiment, although the collar part 20 and the groove part 30 are formed by the same width, it is not restricted to this, For example, the width | variety of the collar part 20 in the center area of the X direction of the surface sheet 10 is made into the collar in a side part area. The width of the portion 20 may be wider. Or it can be set as a desired form, such as making the width | variety of the collar part 20 and the groove part 30 random.

  The substantial thickness of the collar portion 20 is preferably 60 to 100%, particularly 70 to 100% of the apparent thickness. It is preferable that the substantial thickness itself of the collar portion 20 is 0.2 to 4 mm, particularly 0.3 to 3 mm, at the largest portion (top portion 21). When the collar portion 20 has such a thickness, the collar portion 20 is unlikely to fall down, the cushioning property of the topsheet 10 is improved, and the liquid absorbability (liquid passage property) is further improved. Further, when the substantial thickness of the collar portion 20 is thinner than the apparent thickness, specifically, when it is 90% or less, even when the cage sheet 1 is deformed into a curved shape when the cage sheet 1 is used, A gap generated between the top sheet 10 and the low density sheet 12 is prevented from becoming large. Moreover, the surface sheet 10 fits a wearer's skin flexibly. In addition, the substantial thickness of the groove part 30 is 0.1-1 mm.

  The brim portion 20 and the groove portion 30 have different substantial basis weights. In other words, the amount of fiber is different between the flange 20 and the groove 30. Specifically, the amount of fibers is substantially larger in the flange portion 20 than in the groove portion 30. Since the heel part 20 and the groove part 30 are formed in this way, the heel part 20 is not easily crushed against compression behavior in the thickness direction such as wearing pressure, and the compression pressure by the wearer's thigh is It is possible to flexibly deform the bending behavior in the width direction by the flexibility of the groove portion 30.

When the fiber weight of the collar part 20 and the groove part 30 is expressed by basis weight, the basis weight of the collar part 20 is preferably 30 to 180 g / m ² , particularly preferably 40 to 130 g / m ² . On the other hand, it is preferable that the basic weight of the groove part 30 is 10-70 g / m < ² >, especially 15-50 g / m < ² >. The basis weight of the top sheet 10 as a whole is preferably 30 to 120 g / m ² , particularly preferably 30 to 100 g / m ² from the viewpoints of flexibility and nonwoven fabric strength. The basis weight of the collar part 20 is determined from the weight and area of the collar part 20 from which the groove part 30 is removed. As with the apparent thickness measurement, the boundary between the flange portion 20 and the groove portion 30 is based on the cross-sectional shape of the surface sheet 10 to be measured, and the inflection point is used as a reference point (priority) or a 45 ° tilt position. Is the reference point. The top sheet 10 is cut along a straight line connecting the two upper and lower reference points to obtain the flange 20 and its weight is measured. The weight of the groove part 30 is calculated | required from the difference of the weight of the surface sheet 10 before a cutting | disconnection, and the weight of the collar part 20. FIG. Since the area of the groove part 30 is required for calculating the basis weight of the groove part 30, it is measured using an image analyzer or the like which will be described later.

  The front surface layer 10A is less hydrophilic than the back surface layer 10B. More specifically, the contact angle of the constituent fibers of the surface layer 10A is larger than the contact angle of the constituent fibers of the back layer 10B (close to 90 °). Here, the contact angle is an index indicating the level of hydrophilicity of the fiber, and is an angle between a water droplet on the fiber and the fiber surface, which is measured by a measurement method described later. The smaller the contact angle, the more the fiber. It can be judged that the hydrophilicity of is high. Usually, the contact angle of the constituent fibers of the surface sheet of this type of absorbent article is 50 ° or less, and it can be said that the fibers having a contact angle of 30 ° or less have high hydrophilicity. The fibers having a contact angle of 60 to 85 ° are fibers having low hydrophilicity, and the surface sheet 10 including such low hydrophilic fibers has low surface hydrophilicity.

  The surface layer 10 </ b> A is convexly curved toward the skin contact surface side at the heel portion 20, and is concavely curved toward the skin contact surface side at the groove portion 30. That is, the surface layer 10A has a skin contact surface side at the heel portion 20 and protrudes toward the wearer's skin side of the sheet 1 and has a concave shape on the non-skin contact surface side. The non-skin contact surface side protrudes toward the back surface layer side, thereby forming a wave shape along the X direction.

In the surface layer 10A, the constituent fibers are not evenly distributed (the actual thickness is not uniform), and the portion where the amount of the constituent fibers (fiber amount) is relatively large and the portion (the substantial thickness). A relatively thick part and a thin part). The surface layer 10 </ b> A according to the first embodiment has the largest amount of fibers at the top portion 21 of the flange portion 20 and the smallest amount of fibers at the groove portion 30. The amount of fibers in the surface layer 10A decreases from the top 21 toward the groove 30. When the fiber weight of each part in the surface layer 10 </ b> A is expressed by basis weight, the basis weight at the top 21 is preferably 15 to 40 g / m ² , particularly 20 to 35 g / m ² , and between the top 21 and the groove 30. The basis weight in the intermediate part (the part to which the symbol b is attached in FIG. 4) is preferably 10 to 40 g / m ² , particularly 15 to 30 g / m ² , and the basis weight in the groove part 30 is 10 It is preferable that it is -35 g / m < ² >, especially 12-30 g / m < ² >.

  Further, the surface layer 10 </ b> A in the first embodiment is not uniform in thickness (substantial thickness), the thickness a at the top portion 21 of the flange portion 20 is the largest, the thickness b at the intermediate portion between the top portion 21 and the groove portion 30, and at the groove portion 30. The thickness decreases in the order of thickness c (thickness a> thickness b> thickness c). The thickness a is preferably 0.6 to 5 mm, particularly preferably 1.0 to 4 mm, the thickness b is preferably 0.4 to 4 mm, particularly preferably 0.5 to 3 mm, and the thickness c is 0.00. It is preferable that it is 2-3 mm, especially 0.3-2 mm.

  As for the intermediate layer 10C, the skin contact surface side (the surface facing the surface layer 10A) is formed with irregularities and has a corrugated shape along the X direction, similar to the surface layer 10A. The contact surface side (opposite surface side to the back surface layer 10B) is substantially flat and has no unevenness.

In the intermediate layer 10C, the constituent fibers are not uniformly distributed in the same manner as the surface layer 10A, and there are a portion where the amount of the constituent fibers (fiber amount) is relatively large and a portion where the amount is small. The intermediate layer 10 </ b> C in the first embodiment has the largest amount of fibers at the top portion 21 of the flange portion 20 and the smallest amount of fibers in the groove portion 30. The amount of fibers in the intermediate layer 10C decreases from the top 21 toward the groove 30. When the fiber weight of each part in the intermediate layer 10 </ b> C is expressed by basis weight, the basis weight at the top 21 is preferably 10 to 100 g / m ² , particularly 15 to 80 g / m ² , and the middle between the top 21 and the groove 30. The basis weight in the part (the part to which the symbol b is attached in FIG. 4) is preferably 5 to 70 g / m ² , particularly 10 to 60 g / m ² , and the basis weight in the groove part 30 is 0 to 30 g. / M ² , particularly 5 to 25 g / m ² is preferable.

The back surface layer 10B is a flat plate-like layer that is flat on both the skin contact surface side and the non-skin contact surface side. In the back layer 10B, the constituent fibers are distributed substantially uniformly throughout the layer, and the thickness is also substantially uniform. The back layer 10B plays a role as a liquid holding layer as will be described later, and it is preferable that a space (a gap between fibers) capable of containing a certain amount or more of liquid is formed therein. From such a viewpoint, the back surface layer 10B has a basis weight of 15 to 40 g / m ² , particularly 20 to 35 g / m ² , and a density of 0.01 to 0.1 g / m ³ , particularly 0.02 to 0.00. It is preferably 06 g / m ³ . Further, the substantial thickness of the back layer 10B is preferably 0.2 to 6 mm, more preferably 0.5 to 3 mm, from the viewpoint of liquid retention.

  The constituent fibers of the back layer 10B are mainly oriented in the thickness direction (Z-axis direction) of the back layer 10B. That is, the constituent fibers of the back layer 10B have a high Z-axis orientation. As described above, the constituent fibers of the back layer 10B are present with the length direction being substantially coincident with the Z-axis direction, thereby increasing the amount of space inside the back layer 10B and increasing the amount of liquid retained. Here, “the constituent fibers are mainly oriented in the Z-axis direction” means that the orientation angle is 40 to 140 °, preferably 60 to 120 °, in the following (Fiber orientation evaluation method).

(Fiber orientation evaluation method)
When measuring the orientation angle of the constituent fibers, cross-sectional observation with a microscope is necessary, and it is necessary to capture and measure the shape in which the fibers extend, and it is necessary to evaluate the orientation of the ridge and groove structure in the topsheet Therefore, in the surface layer 10A and the intermediate layer 10C, the cross section inclined by 45 degrees from the MD direction is observed, and in the back surface layer 10B, the MD direction cross section is observed from the CD direction side in the same manner as the contact angle measurement method described later. did. The depth of the measurement sample is 2 mm or less in the case of a KEYENCE microscope VH-8000 with a medium magnification zoom lens, but generally 5 mm or less when an electron microscope (SEM) having a deep focal depth is used. In the present invention, JCM-5100 manufactured by JEOL Ltd. was used. A cross-sectional photograph taken by cross-sectional observation with a microscope is converted into image processing software [Image-PRO PLUS Ver., Manufactured by Nippon Roper Media Cybernetics Co., Ltd.]. 6.2 (Japanese version)], binarize the fiber, perform discrete two-dimensional Fourier transform, and perform XY graphing to obtain a power spectrum. This power spectrum becomes an ellipse when the fiber is oriented, and becomes an ellipse with a large flatness when the fiber is strong, and becomes closer to a perfect circle as the orientation of the fiber is randomized. Here, the orientation angle of the fiber is the inclination of the major axis of the ellipse on the X axis, and the ratio of the major axis to the minor axis is the orientation strength. The method described in “Abstracts of the 26th Annual Meeting of the Cultural Properties Preservation and Restoration Society, 44-45 (2004)” may be performed after the above-described XY graphing by Fourier transform, or the method may be The orientation angle and orientation strength may be obtained from image processing. Further, the orientation angles and orientation strengths of the constituent fibers in the surface layer 10A and the intermediate layer 10C are such that these layers have a concavo-convex shape (groove groove structure). Measurement is performed at a portion that is divided into 3 to 4 in the direction and does not include the flange 20 and the groove 30.

  As a method for orienting the constituent fibers of the fiber layer in the thickness direction, for example, production of a fiber layer by an airlaid method can be mentioned. As is well known, the airlaid method is a method for manufacturing a nonwoven fabric including a step of forming a web by dropping and depositing fibers placed on an airflow onto a net. Moreover, by spraying a fluid such as an air flow in the thickness direction from one surface side of the web to an unbonded web in which fiber entanglement or bonding such as a card web has not occurred as in the manufacturing method described later, A fiber layer (back layer) in which the constituent fibers are mainly oriented in the Z-axis direction can be produced. Thus, the back surface layer 10B obtained by spraying the fluid in the thickness direction from the one surface side of the web is oriented in the thickness direction of the back surface layer 10B from the skin contact surface side toward the non-skin contact surface side. It becomes the structure where the ratio of the fiber which is doing is increasing.

  Further, the intermediate layer 10C in the first embodiment has a thickness direction (Z) of the intermediate layer 10C from the skin contact surface side (surface layer 10A side) toward the non-skin contact surface side (back surface layer 10B side). The ratio of fibers oriented in the axial direction (fiber orientation angle) is increasing. With such a configuration, the flange portion 20 is not easily crushed.

  Further, in the topsheet 10 according to the first embodiment, the surface layer 10A has the lowest Z-axis orientation of the constituent fibers in the collar portion, and the Z-axis orientation of the constituent fibers in the order of the intermediate layer 10C and the back layer 10B. Get higher. That is, the back layer 10B has the highest Z-axis orientation of the constituent fibers among the layers constituting the topsheet 10 having a multilayer structure. Therefore, the proportion of fibers oriented in the thickness direction (Z-axis direction) of the surface sheet 10 increases as the surface sheet 10 as a whole moves from the skin contact surface side to the non-skin contact surface side. With such a configuration, it is possible to increase the liquid permeability while suppressing the fluff of fibers on the surface of the surface sheet 10 and to promote the flow of the liquid on the surface of the surface sheet 10 from the flange 20 to the groove 30. Become. As described above, the orientation angle of the constituent fibers of the back surface layer 10B is 60 to 120 °, and the orientation angles of the surface layer 10A and the intermediate layer 10C are preferably 0 to 30 ° for the surface layer 10A and 10C for the intermediate layer 10C. 5 to 110 °. In addition, regarding the orientation angle of a constituent fiber, about 180-360 degrees, it converts into the range to 0-180 degrees. The orientation angle of the constituent fibers in the surface layer 10A is based on the inclination of the surface sheet 10.

  The container sheet 1 according to the first embodiment includes the top sheet 10 having the three-layer structure as described above, and thus exhibits excellent absorbability with respect to a liquid having a relatively high viscosity such as menstrual blood. That is, the liquid excreted from the body first adheres to the ridge groove structure (the ridge 20 and the groove 30) of the surface layer 10A. As described above, the surface layer 10A is low in hydrophilicity. The liquid adhering to the top portion 21 of the portion 20 and the vicinity thereof is not absorbed (penetrated) at these portions, and moves to the groove portion 30 along the inclined surface of the flange portion 20. The movement of the liquid from the flange portion 20 to the groove portion 30 occurs mainly when the adhesion between the surface layer 10A and the wearer's skin is poor and there is a gap between them. When the properties are good and there are almost no gaps, most of the excreted liquid adheres directly to the groove 30. The liquid adhering to the surface of the groove portion 30 is pushed into the groove portion 30 by the wearer's body pressure in the thickness direction from the skin contact surface side of the sheet 1 when worn, and the surface layer 10A or the intermediate layer It is pushed through 10C into the back layer 10B arranged immediately below it and absorbed.

  When the liquid is pushed into the inside from the surface of the groove portion 30 (surface of the surface layer 10A), the flange portion 20 and the groove portion 30 are formed so as to extend in the longitudinal direction of the raised sheet 1, so that the liquid Diffusion in the width direction of the cage sheet 1 is suppressed, thereby preventing side leakage. Such an absorption behavior of the liquid is easily manifested particularly when the viscosity of the liquid is medium (the viscosity at a liquid temperature of 25 ° C. is about 50 to 300 mPa · s). When the excreted liquid is highly viscous (the viscosity at a liquid temperature of 25 ° C. is approximately 300 mPa · s or more), the absorption behavior is substantially the same as the above-mentioned medium viscosity, but the highly viscous liquid Tends to remain on the surface of the top sheet 10 for a long time compared to the medium-viscous liquid. Therefore, after the high-viscosity liquid adheres to the surface of the groove 30, the liquid of the sheet 1 along the groove 30 It moves to the back surface layer 10B while diffusing in the longitudinal direction. Further, when the excreted liquid has a low viscosity and a low viscosity (viscosity at a liquid temperature of 25 ° C. is less than about 50 mPa · s), there is a strong tendency to be quickly absorbed at the site where the liquid has adhered, and the groove 30 Not only the buttocks 20 absorbs the liquid. Menstrual blood is usually a medium to high viscosity liquid. The viscosity is measured using a Brookfield viscometer.

  Such a phenomenon in the surface sheet 10 (nonwoven fabric) can be explained by using the following Lucas-Washburn formula used for analyzing the penetration of the liquid into the porous material. In the following formula, l is the penetration depth (diffusion distance), r is the capillary radius, γ is the surface tension of the liquid, θ is the contact angle, η is the viscosity, and t is time. According to the Lucas-Washburn equation, the liquid movement control factor in the nonwoven fabric (capillary structure) is r derived from the structure of the capillary structure, and θ indicating the contact state between the surface of the capillary structure and the liquid. Yes, the greater the capillary radius, the higher the surface wettability, the longer the diffusion distance. Here, in the low-viscosity liquid, the viscosity term (η), which is a denominator component, is small, and the capillary force factor due to the wettability term (cos θ) with the fiber surface (nonwoven fabric surface) and the size term (r) of the fiber space of the nonwoven fabric. The influence of (molecular component) is large. For this reason, the low-viscosity liquid diffuses in the capillary structure by capillary force. On the other hand, in the high viscosity liquid, the influence of the viscosity term (η) becomes strong and the influence of the wettability term (cos θ) which is one of the capillary force factors becomes small. Becomes smaller and diffusion in the capillary structure is less likely to occur. However, the influence of the size term (r) of the fiber space of the nonwoven fabric is large, and the liquid easily moves from the coarse fiber portion (groove portion 30) or the opening 31 having a large r. That is, the top sheet 10 according to the present embodiment is less likely to diffuse the highly viscous liquid in the interior thereof than the low viscous liquid, but the high viscous liquid passes through the coarse fiber portion such as the groove 30 and the opening 31. It can be said that the structure is easy to flow.

  In the liquid absorption system in the container sheet 1 of the first embodiment described above, the higher the liquid permeability in the surface layer 10A and the intermediate layer 10C, that is, the speed of the liquid passing through the surface layer 10A and the intermediate layer 10C. The higher the speed, the better the liquid absorbency of the whole cage sheet. The liquid permeability in the surface layer 10A and the intermediate layer 10C is mainly controlled by 1) the cross-sectional shape in the width direction (X direction in FIG. 4) and the fiber amount distribution of each of the layers 10A and 10C. Is done. In the first embodiment, as described above, both the surface layer 10A and the intermediate layer 10C have a corrugated shape on the skin contact surface side along the X direction, and the amount of fibers in the groove 30 is the smallest. In this case, the liquid drawability is the highest, so that the liquid quickly moves to the back layer 10B through both layers 10A and 10C in the groove 30.

  As described above, the surface layer 10A is less hydrophilic than the back layer 10B (the contact angle of the constituent fibers is large), and the contact angle of the constituent fibers is preferably 40 to 88 °, more preferably 60 to 85 °. More preferably, it is 70 to 80 °. If the contact angle is less than 40 °, the hydrophilicity becomes high, and the fiber surface is likely to get wet and may give an unpleasant sensation to the wearer. If the contact angle exceeds 88 °, the hydrophobicity increases. As a result, it is difficult for the liquid to move to the intermediate layer 10C adjacent to the front surface layer 10A or the back surface layer 10B located below the intermediate layer 10C, which may cause leakage. Here, the “contact angle of the constituent fibers of the layer” means the contact angle of the constituent fibers having the lowest contact angle among the plurality of types of constituent fibers of the layer. Control of the fiber contact angle can be performed by selecting a surfactant or the like or a resin constituting the fiber. A surfactant or the like is usually used by kneading into a fiber or applying to a fiber surface. The contact angle is measured as follows. When the contact angle by the following measuring method is less than 40 °, it is hydrophilic, when it is 40 ° or more and less than 90 °, it is low hydrophilic, and when it is 90 ° or more, it is hydrophobic.

(Measurement method of fiber contact angle)
The contact angle of the fiber is performed in the same manner as the contact angle measurement method described in Japanese Patent Application Laid-Open No. 2006-183168 relating to the previous application of the present applicant. Specifically, a KEYENCE microscope VH-8000 was used with a medium-magnification zoom lens (with illumination ring) tilted at 90 °, and the condition was set to 500 times. As the measurement sample, a surface sheet (web) cut into a size of 70 mm in the longitudinal direction and 40 mm in the width direction was used. In the measurement sample, the longitudinal direction is the MD direction / width direction of the web is the CD direction, the measurement environment is 20 ° C./50% RH, and the measurement sample is the web with the measurement surface facing upward. Were set on the measurement stage so that they could be observed from the CD direction. In the measurement sample, the depth is preferably about 0.5 to 2 mm in order to minimize out-of-focus fibers. The reason for observing the web from the CD direction is that the fibers of the web are generally oriented in the MD direction, and the possibility that the fibers are arranged in the width direction of the measurement screen increases. By setting in this way, the lens is observed from a direction perpendicular to the fiber length direction.

  Next, water droplets are attached to the fiber surface with a spray bottle filled with ion exchange water (using a tool that makes the fog state as fine as possible) to the set measurement sample, and within 5 seconds (2 to the best possible). 3 seconds). The reason why it is necessary to capture an image in a short time after the attachment is to prevent the attached water droplet from evaporating due to the light emitted from the measurement unit of the microscope and to prevent the contact angle from being changed by the oil agent. The contact angles at five observation results with clear focal points at both ends or one end of the water droplet were measured, and the average value thereof was defined as “contact angle”. As shown in FIG. 14, the contact angle is measured by drawing a tangent line to the fiber of the water droplet and performing image analysis or a protractor on the image or the printed photograph. The contact angle can be measured by taking out the constituent fibers instead of the top sheet.

  In the cage sheet 1 of the first embodiment, the hydrophilicity of the surface layer 10A and the hydrophilicity of the intermediate layer 10C are substantially the same, that is, both the layers 10A and 10C have low hydrophilicity. It is preferable from the viewpoint of preventing wetting by the liquid and reducing stickiness. Here, “the hydrophilicity is substantially the same” means that the difference in the contact angle of the constituent fibers according to the measurement method described above for both the layers 10A and 10C is in the range of ± 5 °.

  On the other hand, in the cage sheet 1 of the first embodiment, the back surface layer 10B preferably has higher hydrophilicity than the surface layer 10A and the intermediate layer 10C from the viewpoint of liquid conductivity and liquid retention. The difference in the contact angle of the constituent fibers according to the measurement method described above between the front surface layer 10A and the back surface layer 10B (intermediate layer 10C) is preferably 20 ° or more, particularly preferably 30 to 50 °. Moreover, the contact angle of the constituent fibers of the back layer 10B is preferably 20 ° or less to 50 °, more preferably 20 to 40 °. Here, 20 ° or less is a convenient expression when a phenomenon occurs in which the liquid is highly hydrophilic and flows without staying on the fiber. When 20 ° is described, the contact angle is determined by measurement. is made of.

  From the viewpoint of reliably operating the liquid absorption system according to the present invention described above, the back surface layer 10B preferably has a higher fiber density than the surface layer 10A and the intermediate layer 10C. With such a configuration, a viscous liquid such as menstrual blood is prevented from being absorbed by the surface layer 10A and the intermediate layer 10C immediately below the surface layer 10A, and from the groove 30 due to body pressure or the like to the back surface layer 10B. The liquid permeability is further improved, and excellent liquid absorbability can be obtained. If viscous liquid such as menstrual blood is absorbed by the surface layer 10A or the intermediate layer 10C, stickiness may be caused. The fiber density can be controlled by the fiber thickness, shape, crimped shape, fiber resin, and the like.

The fiber density of the back layer 10B is preferably 0.005 to 0.08 g / cm ³ , and more preferably 0.01 to 0.05 g / cm ³ . The fiber density of the surface layer 10A (intermediate layer 10C) is preferably 0.02 to 0.1 g / cm ³ , more preferably 0.04 to 0.08 g / cm ³ . The ratio of the fiber density of the surface layer 10A (intermediate layer 10C) to the fiber density of the back layer 10B [surface layer (intermediate layer) / back surface layer] is preferably 1.2 to 10, more preferably 1.5. ~ 5. The fiber density of each of the surface layer 10A, the intermediate layer 10C, and the back layer 10B is measured by the following method.

(Fiber density measurement method)
As a measurement sample, an absorbent article in which a surface sheet to be measured is incorporated and no load is applied is used. Using an image analysis device or the like, the MD direction cross section of the measurement sample whose size (size) and weight are measured is observed, and the cross sectional area of the MD direction cross section of each layer and the entire measurement sample is calculated. As the image analysis apparatus, the same image analysis apparatus used for measuring the size of the aperture 31 described later can be used. Each layer constituting the top sheet is separated and the weight of each layer is determined. Separately, the volume of each layer is obtained from the cross-sectional area of each layer and the CD direction length of the measurement sample, and the fiber density of each target layer is calculated by dividing the weight by the volume.

  In addition, from the viewpoint of reliably operating the liquid absorption system according to the present invention described above, the flange portion 20 has a top portion in the cross section in the width direction X of the cage sheet 1 as shown in FIGS. It is preferable that 21 bends convexly upward and the width increases from the top 21 toward the bottom. More specifically, the cross-sectional shape of the collar portion 20 is preferably a triangular shape, a mountain shape, a semicircular shape, or the like. Since the flange portion 20 has such a cross-sectional shape, the viscous liquid attached to the top portion 21 of the flange portion 20 and the vicinity thereof moves to the groove portion 30 along the inclined surface of the flange portion 20. Therefore, the above-described liquid absorption system according to the present invention works more reliably. Moreover, the inconvenience that a liquid adheres and remains on the surface of the surface sheet 10 by applying pressure such as body pressure can be suppressed. Furthermore, in addition to the cross-sectional shape of the collar portion 20 being as described above, the top portion 21 (convex portion) is continuously formed in the longitudinal direction Y of the cage sheet 1 as shown in FIG. That is, as described above, it is preferable that the collar portion 20 extends in the longitudinal direction of the sheet 1, and in this case, the height of the top portion 21 continuously formed in the direction Y is constant. Or may vary.

  On the other hand, as shown in FIG. 5, when the top 21 of the flange 20 is flat and is not curved upwardly as shown in FIGS. 2 and 4, the flat top It is difficult for the liquid to move to the groove portion 30 as described above while the liquid remains attached to 21. Therefore, the cross-sectional shape as shown in FIG. 5 (the cross-sectional shape in the width direction of the cage sheet), specifically the trapezoidal shape, the convex shape, the square shape, the rectangular shape, etc. Compared to the collar portion having a cross-sectional shape as shown in FIG. 2 and FIG. 4, the liquid absorbability is inferior, and the liquid tends to remain on the surface sheet.

  As described above, in the first embodiment, the seal portion 15 formed by bonding the top sheet 10 and the back sheet 11 to each other by heat treatment is formed over the entire outer peripheral edge of the cage sheet 1. As described above, since the topsheet 10 has a groove structure composed of groove grooves extending in the longitudinal direction, when the groove structure is heat-treated to form a uniform thickness seal portion, the vicinity of the seal portion There is a possibility that a large step is generated between the groove structure located in the groove and the seal portion, which may lead to discomfort during wearing. In particular, as shown in FIG. 1, when a constricted portion is present in the central portion in the longitudinal direction of the cage sheet, such a problem is likely to occur in the seal portion located in the constricted portion. Therefore, from the viewpoint of reducing the level difference due to the adoption of such a gutter groove structure and obtaining a better wearing feeling, the seal portion 15, particularly the longitudinal center portion of the vaginal discharge sheet 1 or the excretion portion of the wearer is provided. It is preferable that the seal part 15 located in the constriction part which exists in the opposite excretion part opposing part is decreasing in thickness as it goes to the outer periphery from the inner periphery. The seal part 15 having such a thickness distribution is a part that becomes an outer peripheral edge from a part that becomes the inner peripheral edge of the seal part 15 in both sheets 10 and 11 when the top sheet 10 and the back sheet 11 are heat-treated as usual. The pressure is obtained in multiple stages toward the surface, and the pressure in each stage is increased as it goes toward the outer peripheral portion.

  From the above viewpoint, it is preferable that the seal portion 15 is formed in a linear shape in a direction generally along the appearance shape of the cage sheet 1. Further, from the viewpoint of stabilizing the sealing portion 15 while improving the flexibility of the cage sheet 1, the sealing portion 15 includes a plurality of sealing portions that do not intersect with each other in a plan view (top view) as shown in FIG. From the viewpoint of making it difficult to leak, it is preferable that the line (compressed portion of the surface sheet) constituting the seal portion is a surface sheet 10 in a plan view. It is preferable to have the part which overlaps with the collar part 20. Moreover, it is preferable from the viewpoint of the strength of the seal portion 15 that the seal portion 15 includes an adhesive.

  Next, constituent materials of the cage sheet 1 according to the first embodiment will be described. As the back sheet 11, those used in this type of conventional absorbent article can be used without any particular limitation. As the back sheet 11, a liquid-impermeable or water-repellent material, for example, a film made of a thermoplastic resin, or a laminate of a nonwoven fabric can be used. A spunbond-meltblown-spunbond (SMS) nonwoven fabric or a spunbond-meltblown-meltblown-spunbond (SMMS) nonwoven fabric can also be used. The back sheet 11 may have moisture permeability. Examples of the back sheet having moisture permeability include a porous film obtained by extruding a resin composition containing a thermoplastic resin and fine particles incompatible with the thermoplastic resin into a film shape and uniaxially or biaxially stretching, and the above-described SMS nonwoven fabric. It is done.

  As constituent fibers of the surface sheet 10 (surface layer 10A, intermediate layer 10C, back layer 10B), fibers conventionally used in the technical field such as natural fibers, semi-natural fibers, synthetic fibers and the like can be used without particular limitation. it can. From the viewpoint of imparting flexibility to the topsheet 10 without causing clogging between fibers, it is preferable to use synthetic fibers. The blending amount of the synthetic fiber is preferably 50% by weight or more, more preferably 70% by weight or more of the entire surface sheet. Of course, you may comprise the surface sheet 10 from 100% of synthetic fiber. When the topsheet 10 is made of 100% synthetic fiber, the grooving structure is not easily crushed even under the condition where the body pressure of the wearer is applied, so that the air permeability along the groove 30 is good.

  As a synthetic fiber used for the surface sheet 10, the core-sheath structure fiber and the side-by-side type fiber which are self-bonding fibers are mentioned, for example. In addition, single fibers and composite fibers such as polyethylene, polypropylene, and polyester can be used. From the viewpoint of the groove-shaped structure and the formability of the aperture shape, it is preferable to use a core-sheath structure fiber having polyethylene as a sheath component and a side-by-side fiber having a polyethylene portion. The (average) fineness of the fiber is preferably in the range of 1 to 6 dtex.

  It is preferable to use crimped fibers as the synthetic fibers used for the topsheet 10 because the cushioning properties of the topsheet 10 are further improved. As the crimped fiber, either a two-dimensionally crimped fiber or a coiled three-dimensionally crimped fiber can be used.

  As the synthetic fiber used for the topsheet 10, it is preferable to use a fiber that is elongated by application of heat because the cushioning property of the topsheet 10 is further enhanced. This is because clogging between fibers due to heat applied during the manufacture of the topsheet 10 is prevented. As such a fiber, for example, WO2007 / 66599 according to the previous application of the present applicant can be mentioned.

  When any of the above-described crimped fibers and heat-extensible fibers is used, it is preferable that those fibers are mixed in the surface sheet 10 in a total amount of 30 to 70% by weight.

  The cage sheet 1 of the first embodiment is used by being fixed to the inner surface of the undergarment via an adhesive portion (not shown) disposed on the surface of the back sheet 11. The cage sheet 1 of the first embodiment is excellent in liquid absorbency due to the action of the liquid absorption system described above, and not only for low-viscosity liquids such as urine but also for relatively high-viscosity body fluids such as menstrual blood. In addition, since it can be absorbed and held inside the sheet 1 without leaving it on the top sheet, stickiness hardly occurs and a feeling of use such as a feeling of wearing is good.

  6 and 7 show a cage sheet which is a second embodiment of the absorbent article of the present invention. In the second embodiment, components that are different from the above-described cage sheet of the first embodiment will be mainly described, and the same components will be denoted by the same reference numerals and description thereof will be omitted. For the components not specifically described, the description of the cage sheet of the first embodiment is applied as appropriate.

  As shown in FIGS. 6 and 7, the cage sheet of the second embodiment is a two-layer structure in which the top sheet 10 has a top layer 10A and a back layer 10B, and the top sheet has a three-layer structure. Different from the cage sheet of one embodiment. Moreover, 10 A of surface layers in 2nd Embodiment have the opening 31 in the groove part 30, and also differs from the cage sheet of 1st Embodiment which does not have the opening 31 also in this point. The formation of the opening 31 is mainly caused by the layer structure of the topsheet. That is, when the surface sheet has a two-layer structure as in the second embodiment, the layer (the back surface in the second embodiment) located immediately below the surface layer (the layer in contact with the wearer's skin) in the surface sheet having the two-layer structure. Since the layer 10B) needs a liquid holding ability, it is desirable to form an opening in the surface layer for improving the liquid permeability. On the other hand, when the surface sheet has a multilayer structure of three or more layers as in the first embodiment, as described above, the cross-sectional shape and fibers of the surface layer and the layer located immediately below the surface layer (intermediate layer 10C in the first embodiment) According to the quantity distribution, the liquid permeability in the surface layer region of the surface sheet having a three-layer structure is controlled, so that it is not particularly necessary to form openings in the surface layer for the purpose of ensuring the liquid permeability.

  As shown in FIG. 6, the apertures 31 are regularly formed at regular intervals along the direction in which the groove 30 extends. Therefore, in the surface layer 10A in the second embodiment, an aperture array composed of a large number of apertures 31 arranged at a constant interval along the Y direction (longitudinal direction of the cage sheet) is provided on the surface layer. It is in a state where it is formed in multiple rows over the X direction of 10A (the width direction of the cage sheet). The pitch of the arrangement of the apertures 31 in all aperture rows is the same. In two adjacent aperture rows, the aperture 31 is located at the same position in the X direction of the surface layer 10A. And when the whole sheet | seat whole area is seen along the X direction of 10 A of surface layers, this hole 31 is arrange | positioned so that the site | part in which the hole 31 is not necessarily formed exists. Further, when viewed on the entire surface layer 10A, the apertures 31 are distributed and arranged so as to form a multi-row row in the X direction of the surface layer 10A and also a multi-row row in the Y direction. By arranging the apertures 31 in this way, the apertures 31 can be efficiently formed by dividing the fibers as compared with the case where the apertures 31 are arranged in a staggered pattern, for example. Can do.

  The opening 31 is formed by dividing the constituent fibers of the surface layer 10A. In the vicinity of the end of the opening 31, a film-like structure resulting from the thermal deformation of the fiber is not formed. Due to this, the vicinity of the end portion of the opening 31 has low rigidity, and is excellent in flexibility and shape restoration property against deformation. Further, since the liquid passes through the structure, the liquid does not collect near the end of the opening 31. When viewed as the entire surface sheet, the constituent fibers are basically entangled between the fibers or the fibers are fused. Thereby, the form of the nonwoven fabric is maintained.

The opening 31 can take various shapes in a plan view of the surface layer 10A. For example, a shape such as a circle, an oval, an ellipse, a triangle, a quadrangle, a hexagon, or a combination thereof can be given. What is necessary is just to determine suitably the shape and magnitude | size of the opening 31 according to the specific use of an absorbent article. The size of the opening 31 is preferably about 0.5 to ⁵ mm ² in terms of the projected area of the surface layer 10A in plan view from the viewpoint of liquid permeability and maintaining the strength of the surface layer 10A. The size of the opening 31 is measured using an image analysis device. Specifically, a light source [Sunlight SL-230K2; manufactured by LPL Co., Ltd.], stand [copy stand CS-5; manufactured by LPL Co., Ltd.], lens [24 mm / F2.8D Nikkor lens], CCD camera [(HV-37; manufactured by Hitachi Electronics Co., Ltd.) F-mount connection with lens] and video board [Spectra 3200; manufactured by Canopus Co., Ltd.] take in. The captured image is binarized by the image analysis software NEW QUABE (ver. 4.20) manufactured by NEXTUS. The average value of the individual areas obtained from the binarized image is taken as the size of the aperture.

  Also in the second embodiment, from the same viewpoint as in the first embodiment, it is preferable that the surface layer 10A has a lower hydrophilicity (a contact angle between constituent fibers is larger) than the back layer 10B, and the back layer 10B has a surface The fiber density is preferably higher than that of the layer 10A. The back layer 10B in the second embodiment has its constituent fibers oriented mainly in the thickness direction (Z-axis direction) of the back layer 10B, and from the skin contact surface side to the non-skin contact surface side. As it goes, the ratio of fibers oriented in the thickness direction of the back layer 10B increases.

  The same effect as the cage sheet of the first embodiment can be obtained by the cage sheet of the second embodiment. In particular, since the top sheet has a two-layer structure, the configuration of the cage sheet according to the second embodiment described above is also suitable for a cage sheet (panty liner) having a small thickness.

  Next, the suitable manufacturing method of the absorbent article of this invention is demonstrated taking the manufacturing method of the cage sheet of each embodiment mentioned above as an example.

  The manufacturing method of the absorbent article of the first embodiment is a manufacturing method of the above-described cage sheet (the top sheet has a three-layer structure) according to the first embodiment. First, the manufacturing method of the surface sheet 10 shown in FIG.3 and FIG.4 is demonstrated. The top sheet 10 having a three-layer structure is manufactured using an apparatus 40 shown in FIG. The manufacturing method using this apparatus 40 is as follows: (a) A surface layer precursor 10A ′ and an intermediate layer precursor 10C ′ are sequentially laminated on a concavo-convex shaping belt to obtain a laminate, and the concavo-convex shaping A step of pressing together with the belt, (b) a step of spraying a fluid from the intermediate layer precursor 10C ′ side to the laminated body located on the concavo-convex shaping belt, and (c) the laminating located on the concavo-convex shaping belt. A step of laminating the back layer precursor 10B ′ on the body to form a laminate having a three-layer structure, and spraying fluid from the back layer precursor 10B ′ side on the laminate of the three layer structure; and (d) the three-layer structure. The laminate is subjected to a hot air treatment to make the laminate into a nonwoven fabric.

  The surface layer precursor 10 </ b> A ′ finally becomes the surface layer 10 </ b> A constituting the surface sheet 10 of the first embodiment described above, and is a fiber assembly including the constituent components of the surface layer 10 </ b> A. The intermediate layer precursor 10 </ b> C ′ finally becomes the intermediate layer 10 </ b> C constituting the top sheet 10 of the first embodiment described above, and is a fiber assembly including the constituent components of the intermediate layer 10 </ b> C. The back surface layer precursor 10B 'finally becomes the back surface layer 10B constituting the top sheet 10 of the first embodiment described above, and is a fiber assembly including the constituent components of the back surface layer 10B. These fiber aggregates include those in which fibers such as card webs are not bonded or entangled (unbonded web), or those having a low degree (weakly bonded web), fibers such as nonwoven fabric, What has entangled (bonding web) can be used. Any of these webs may be used as the intermediate layer precursor 10C 'and the back layer precursor 10B', and an unbonded web having the lowest tensile strength among them may be used. On the other hand, since the surface layer precursor 10A ′ is required to have a function as a conveyance support, it is preferable that the surface layer precursor 10A ′ has a certain degree of tensile strength. From this viewpoint, the surface layer precursor 10A ′ is weakly bonded. It is preferable to use a web or a bonded web. Weakly bonded webs and bonded webs can be obtained by subjecting unbound webs to known non-woven fabric processing (air-through processing, spunlace processing, etc.).

  The apparatus 40 shown in FIG. 8 includes an uneven shaping belt 41 and a pair of pressing rolls 50 and 51. The concavo-convex shaping belt 41 functions as a transport belt for transporting the laminate, and as shown in FIG. 9, has a first surface 41a and a second surface 41b opposite to the first surface 41a. The first surface 41a is a surface on which the stacked body is placed, and the second surface 41b is a surface on which the stacked body is not placed. The concavo-convex shaping belt 41 includes a crest 42 and a trough 43 extending in a direction [CD (Cross Direction)] orthogonal to the transport direction of the laminate (direction indicated by an arrow MD in FIG. 8, Machine Direction (MD)). It has alternately. The crests 42 and the troughs 43 are alternately arranged over a direction (MD) perpendicular to the extending direction (CD). The concavo-convex shaping belt 41 protrudes toward the first surface 41 a at the peak portion 42, and is concavely curved toward the first surface 41 a side at the valley portion 43. A number of holes 45 penetrating the concavo-convex shaping belt 41 in the thickness direction are formed in a portion excluding the top portion 44 of the mountain portion 42 and the vicinity thereof. The height difference between the peak portion 42 and the valley portion 43 is substantially the same throughout the belt 41. Moreover, as for a pair of press rolls 50 and 51, the cross-sectional shape of the direction orthogonal to the axial direction of a roll has made perfect circle shape as shown in FIG. 8, and the surrounding surface is smooth and does not have an unevenness | corrugation. . The concavo-convex shaping belt 41 passes between the pair of pressing rolls 50, 51, the pressing roll 50 is on the first surface 41 a side of the concavo-convex shaping belt 41, and the pressing roll 51 is the concavo-convex shaping belt 41. Are arranged on the second surface 41b side.

  The apparatus 40 shown in FIG. 8 includes a first injection nozzle 52 and a second injection nozzle 53. The first spray nozzle 52 and the second spray nozzle 53 are arranged so as to face the first surface 41 a of the uneven shaping belt 41. Each of the nozzles 52 and 53 has a structure capable of ejecting fluid over the entire width of the uneven shaping belt 41. In the nozzles 52 and 53, the first injection nozzle 52 is located on the upstream side and the second injection nozzle 53 is located on the downstream side in the transport direction MD of the laminate. In addition, suction boxes 54 and 55 for sucking fluid ejected from the nozzles are arranged on the opposite sides of the nozzles 52 and 53 with the concavo-convex shaping belt 41 interposed therebetween so as to face the nozzles.

  As the fluid ejected from the first ejection nozzle 52 and the second ejection nozzle 53, a liquid such as water and a gas such as air can be used. The type of fluid is appropriately selected according to the fiber aggregate (each of the precursors) guided onto the uneven shaping belt 41. In the first embodiment, both the first injection nozzle 52 and the second injection nozzle 53 inject a water vapor flow.

  In step (a), the surface layer precursor 10A ′ and the intermediate layer precursor 10C ′ are sequentially laminated on the first surface 41a of the uneven shaping belt 41 to obtain a laminate, and the laminate is uneven. Together with the shaping belt 41, it passes between a pair of pressing rolls 50, 51 rotating in the direction of the arrow in FIG. At this time, as shown in FIG. 10A, the laminate is pressed in the thickness direction between the pressing roll 50 and the uneven shaping belt 41, whereby the first surface of the uneven forming belt 41. Deforms along 41a. The first surface 41a of the concavo-convex shaping belt 41 is completely covered with the deformed laminate. In the laminated body, the portion that contacts the top portion 44 of the peak portion 42 of the uneven shaping belt 41 is the portion that finally becomes the groove portion 30, and the portion that contacts the valley portion 43 of the uneven shaping belt 41 is the final portion. In particular, this is a portion that becomes the top portion 21 of the flange portion 20.

  Next, in step (b), the fluid ejected from the first ejection nozzle 52 is sprayed from the intermediate layer precursor 10 </ b> C ′ side onto the laminate deformed on the uneven shaping belt 41. The sprayed fluid blows out to the opposite side through the hole 45 of the uneven shaping belt 41. Due to the pressure of this fluid spraying, the constituent fibers mainly on the fluid spraying surface side of the intermediate layer precursor 10C ′ are oriented in the thickness direction of the precursor 10C ′ as shown in FIG. As a result, the above-described configuration of the intermediate layer 10C (the proportion of fibers oriented in the thickness direction of the intermediate layer 10C is increased from the skin contact surface side toward the non-skin contact surface side). .

  Next, in the step (c), a back surface layer precursor 10B ′ is laminated on the laminate composed of the surface layer precursor 10A ′ and the intermediate layer precursor 10C ′, which is located on the uneven shaping belt 41, and 3 It is set as the laminated body of a layer structure. Then, the fluid sprayed from the second spray nozzle 53 is sprayed from the back surface layer precursor 10 </ b> B ′ side to the laminate having the three-layer structure. With the pressure of this fluid spray, the constituent fibers of the back layer precursor 10B 'are oriented in the thickness direction of the precursor 10B' as shown in FIG. As a result, the above-described configuration of the back layer 10B (the constituent fibers of the back layer 10B are mainly oriented in the thickness direction of the back layer 10B, and from the skin contact surface side toward the non-skin contact surface side, The ratio of fibers oriented in the thickness direction of the back layer 10B is increased).

  Next, in the step (d), the laminated body having the three-layer structure is subjected to hot air treatment to form a nonwoven fabric. The hot air treatment device 56 used in the step (d) is capable of blowing hot air over the entire width of the laminated body from the front surface side to the back surface side (unevenness shaping belt 41 side). It is comprised similarly to the well-known hot-air processing apparatus used for manufacture of a normal air through nonwoven fabric. By the hot air treatment of this laminate, each layer is made into a nonwoven fabric, and the layers are joined and integrated, and further, the bulk of the nonwoven fabric that has become clogged is restored, or fiber deformation (crimping or stretching) is manifested. And a long topsheet 10 is obtained. The hot air treatment may be performed in one stage, or may be performed in a plurality of stages, for example, a hot air treatment for promoting the formation of a nonwoven fabric and a hot air treatment for restoring the bulk of the nonwoven fabric.

  The long topsheet 10 thus obtained is processed according to a conventional method together with a separately manufactured backsheet 11 to obtain the target cage sheet 1 of the first embodiment.

  Next, the manufacturing method of the absorbent article of the second embodiment will be described. Regarding the second embodiment, components that are different from the manufacturing method of the first embodiment described above will be mainly described, and similar components will be denoted by the same reference numerals and description thereof will be omitted. The description of the manufacturing method of the first embodiment is appropriately applied to components that are not particularly described.

  The manufacturing method of the absorbent article of the second embodiment is a manufacturing method of the above-described cage sheet of the second embodiment (the sheet having a two-layered surface sheet and having openings formed therein). First, the manufacturing method of the surface sheet 10 shown in FIG.6 and FIG.7 is demonstrated. The topsheet 10 having a two-layer structure and having openings formed therein is manufactured using an apparatus 60 shown in FIG. The manufacturing method using this apparatus 60 includes the steps of (e) placing the surface layer precursor 10A ′ on the uneven shaping belt and pressing the surface layer precursor 10A ′ together with the uneven shaping belt; ) A step of forming a hole by directly spraying the surface layer precursor 10A ′ located on the concavo-convex shaping belt; and (g) on the surface layer precursor 10A ′ located on the concavo-convex shaping belt. A back layer precursor 10B ′ is laminated to form a two-layer laminate, and a fluid is sprayed from the back layer precursor 10B ′ side to the two-layer laminate, and (h) the two-layer laminate. It has the process of giving a hot-air process to a body and making this laminated body into a nonwoven fabric.

  An apparatus 60 shown in FIG. 11 includes an uneven shaping belt 61 and a pair of pressing rolls 70 and 51. As shown in FIG. 12, the uneven shaping belt 61 has a first surface 61a and a second surface 61b opposite to the first surface 61a. The concavo-convex shaping belt 61 is different from the concavo-convex shaping belt 41 in the first embodiment in that a plurality of notches 47 are formed in the top portion 44 of the peak portion 42 protruding to the first surface 61a side. The plurality of notches 47 are arranged in parallel at each apex 44 at a predetermined interval in a direction (CD) orthogonal to the conveyance direction (MD) of the uneven shaping belt 61. Each notch 47 has a substantially semi-elliptical shape when viewed from a CD. The cutout portion 47 is used for forming a portion other than the opening 31 (non-opening portion) in the groove portion 30 in the topsheet 10 shown in FIG. Moreover, the press roll 70 is different from the press roll 50 in the first embodiment in that an uneven surface including a concave portion 71 and a convex portion 72 is formed on the peripheral surface as shown in FIG. The concave portions 71 and the convex portions 72 both extend in the roll axis direction of the pressing roll 70 and are alternately arranged in a direction (rotating direction of the pressing roll 70) perpendicular to the extending direction. The concave portion 71 has a width that allows the peak portion 42 of the concave and convex shaping belt 61 to be inserted.

  In step (e), the surface layer precursor 10A ′ is placed on the first surface 61a of the uneven shaping belt 61, and the surface layer precursor 10A ′ together with the uneven shaping belt 61 is shown in FIG. It passes between a pair of press rolls 70 and 51 rotating in the direction of the middle arrow. During this passage, as shown in FIG. 13A, the crest 42 (the top 44) of the uneven shaping belt 61 is inserted into the recess 71 formed in the peripheral surface of the pressing roll 70. The rotation speed of the roll and / or the conveyance speed of the uneven shaping belt 61 is adjusted. The surface layer precursor 10 </ b> A ′ is pressed in the thickness direction between the pressing roll 70 and the concavo-convex shaping belt 61, thereby deforming along the first surface 61 a of the concavo-convex shaping belt 61.

  Next, in the step (f), as shown in FIG. 13B, the fluid jetted from the first jet nozzle 52 is directly sprayed onto the surface layer precursor 10 </ b> A ′ deformed on the uneven shaping belt 61. The pressure of this fluid spray causes the constituent fibers to be separated. By this shifting, the constituent fibers of the surface layer precursor 10 </ b> A ′ move into the valleys 43 located between the peaks 42 of the uneven shaping belt 61. That is, fiber distribution occurs. In particular, in the portion (non-notched portion) other than the notched portion 47 in the top portion 44 of the peak portion 42, the segregation of the constituent fibers is further promoted, and the surface layer precursor 10A ′ positioned on the non-notched portion is formed. A hole is formed. This hole becomes the opening 31 in the surface sheet 10 shown in FIGS. On the other hand, no hole is formed in the surface layer precursor 10 </ b> A ′ located on the notch 47.

  Next, in step (g), the back surface layer precursor 10B 'is stacked on the surface layer precursor 10A' located on the uneven shaping belt 61 to form a stacked structure having a two-layer structure. Then, the fluid sprayed from the second spray nozzle 53 is sprayed from the back surface layer precursor 10 </ b> B ′ side to the laminate having the two-layer structure. With the pressure of this fluid spray, the constituent fibers of the back layer precursor 10B 'are oriented in the thickness direction of the precursor 10B' as shown in FIG. As a result, the above-described configuration of the back surface layer 10B (the constituent fibers of the back surface layer 10B are mainly oriented in the thickness direction of the back surface layer 10B, and the back surface is moved from the skin contact surface side toward the non-skin contact surface side. The proportion of fibers oriented in the thickness direction of the layer 10B is increased). Next, in the step (H), the laminate having the two-layer structure is subjected to hot air treatment to make the laminate into a nonwoven fabric.

  The long topsheet 10 thus obtained is processed according to a conventional method together with a separately manufactured backsheet 11 to obtain a target cage sheet 1 according to the second embodiment.

  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, the surface sheet according to the present invention may have a multilayer structure of four or more layers. In this case, in the topsheet 10 having the three-layer structure in the first embodiment, a layer between the intermediate layer 10C and the back surface layer 10B is oriented in the Z-axis like the back surface layer and the gap between the fibers is larger than the back surface layer. It is preferable from the viewpoint of holding the highly viscous liquid without spreading on the surface. Further, the surface layer 10A in the first embodiment may have the opening 31 in the groove 30 as in the second embodiment.

Further, an absorber may be interposed between the top sheet 10 and the back sheet 11. As the absorber, paper; a pulp layer including wood fluff pulp; a polymer sheet (for example, an absorbent polymer disposed between fiber sheets such as two sheets of paper) and the like can be used. The pulp layer may contain an absorptive polymer usually used in the technical field, and the whole pulp layer may be covered with tissue paper. The basis weight of the absorber is preferably 50 to 300 g / m ² , and the thickness under no load is preferably 0.5 to 1.0 mm.

  Further, a leak-proof cover sheet may be disposed on the top sheet 10 in the left and right side regions of the cage sheet 1. In addition, a pair of wing portions extending outward in the width direction may be provided on both side edges in the longitudinal direction of the cage sheet 1. Moreover, in the said embodiment, although the sheet | seat (panty liner) was mentioned as one of the application examples of the absorbent article of this invention, For example, it can apply also to absorbent articles, such as a sanitary napkin and an incontinence pad. Each structure mentioned above can be combined suitably.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to such examples.

[Example 1]
Using a 2.2 dtex × 38 mm core-sheath structure fiber of sheath component polyethylene / core component polyester, a non-woven fabric is formed by a steam flow according to the manufacturing method of the first embodiment described above, and the groove structure as shown in FIGS. And the surface sheet of Example 1 which has a hole was obtained. The obtained top sheet was 3 mm in width of the ridge part, 2 mm in width of the groove part, and 1.2 mm in thickness (apparent thickness at the top part of the ridge part). For the thickness, the top sheet was heated to 60 ° C. It was adjusted to 0.7 mm by inserting between press rolls and compressing. In this example, the basis weight of the surface layer precursor is 20 g / m ² , the basis weight of the intermediate layer precursor is 20 g / m ² , the basis weight of the back layer precursor is 20 g / m ² , and the intermediate layer precursor And the hydrophilic processing agent used for the constituent fiber of a back surface layer precursor has high durability with respect to water compared with the hydrophilic processing agent used for the constituent fiber of a surface layer precursor. Using the thus obtained top sheet and back sheet (polyethylene resin film having a basis weight of 22 g / m ² ), a sheet having a cross section as shown in FIG. It was. The sheets in the sample are bonded by a hot melt adhesive spiral method (adhesive application amount 5 g / m ² ). The outer shape of the obtained sample was a violin type having a length of 150 mm in the longitudinal direction and a length of 60 mm in the width direction. The thickness of the sample was about 1.2 mm.

[Example 2]
In Example 1, the surface sheet was obtained according to the manufacturing method of the second embodiment described above, the basis weight of the back surface layer precursor was 40 g / m ^2, and the air flow was used for the second injection nozzle. A sheet was prepared in the same manner as in Example 2, and this was used as the sample of Example 2.

[Comparative Example 1]
In Example 1, the hydrophilic treatment agent used for the constituent fibers of the front layer precursor is the same as that used in the constituent fibers of the intermediate layer precursor and the back layer precursor. A sheet was prepared and used as a sample of Comparative Example 1.

[Comparative Example 2]
A commercially available cage sheet (trade name “Laurier F Panty Liner” manufactured by Kao Corporation) was used as a sample of Comparative Example 2. The surface sheet in this sample has a two-layer structure of an upper layer and a lower layer, and the surface side of the upper layer corresponds to the surface layer, the back side of the upper layer corresponds to the intermediate layer, and the lower layer corresponds to the back layer. Further, in the surface sheet of this sample, a plurality of ridges (convex parts) are arranged discontinuously at predetermined intervals in the longitudinal direction of the sheet, and are arranged in a staggered manner in plan view, It is not formed continuously so as to extend in the longitudinal direction.

[Performance evaluation]
For the cage sheets obtained in the examples and comparative examples, the amount of fibers in each of the flange portion and the groove portion of the top sheet is evaluated, and the contact angles of the constituent fibers of the front surface layer, the intermediate layer, and the back surface layer by the method described above and The orientation angle was evaluated. Moreover, the liquid spreading, stickiness, and smoothness were evaluated by the following methods, respectively. These results are shown in Table 1 below.

<Liquid spreading>
Evaluation was performed using a highly viscous liquid. As the highly viscous liquid, suspected soft stool prepared by the following method was used. 0.5 g of the highly viscous liquid is gently dropped using a dropper while touching the top sheet of the sample, and the spread after 10 seconds is measured. When 30 seconds have elapsed since the high-viscosity liquid was dropped, an acrylic plate of 50 × 50 mm thickness 5 mm is placed on the center of the surface sheet where the high-viscosity liquid is diffusing, and is further applied to the high-viscosity liquid by a weight. The load is adjusted to 20 g / m ² . The weight and acrylic plate are removed after 1 minute of pressurization, and the spread area of the liquid after pressurization is determined. The diffusivity is obtained by using a value obtained by dividing the difference between the liquid spreading areas before and after pressurization by the liquid spreading area before pressurization as a percentage. It can be evaluated that the lower the diffusivity is, the less the liquid spreads and the liquid is transferred to the lower layer side (low density sheet side) than the top sheet. The diffusivity is preferably 25% or less, more preferably 15% or less, and most preferably a negative value.

  The suspected loose stool was prepared as follows. 100 g of skim milk [Snow Brand Milk Products Co., Ltd.] and 100 g of wheat flour [Nisshin Flour Milling Co., Ltd.] were thoroughly mixed in a container, and gradually added to 500 g of ion-exchanged water while stirring with a stirrer. Further, 500 g of ion-exchanged water was added to completely disperse them, and the container was placed in a 90 ° C. water bath and stirred for 90 minutes (stirring speed: 32 rpm). After the stirring, the whole container was cooled with ice water, and 3.6 g of preservative (Proxel XL-2) was added after the inside of the container became 50 ° C. or lower. Furthermore, after sufficiently stirring with a spatula, it was put in a refrigerator and allowed to stand until the next day to obtain a stock solution. In use, ion-exchanged water was added to the stock solution to adjust the viscosity at a liquid temperature of 25 ° C. to 300 mPa · s. The viscosity of the suspected soft stool was measured with a Brookfield viscometer (manufactured by Tokyo Keiki Co., Ltd.).

<Stickiness>
In the evaluation of <Liquid Spread>, the surface state (the remaining amount of the liquid) of the surface sheet after removing the weight and the acrylic plate after 1 minute of pressure was visually observed, and the pressurized part was touched with a finger. The tactile sensation is confirmed, and the stickiness is evaluated comprehensively from both results. As for the surface state, the remaining state of the high-viscosity liquid is evaluated in three stages. If the remaining high-viscosity liquid is less than 10% of the spread portion, ◯ is 10% or more and 30% or less. When exceeding, it is set as x. The remaining amount of the liquid is preferably determined based on the presence or absence of gloss. On the other hand, the tactile sensation is ◯ when the surface of the top sheet is not wet when touched with a finger, and x when the surface is wet.

<Smoothness>
When the surface sheet of the sample is touched with a finger along both the width direction and the longitudinal direction and no roughness is felt, ◯ is given. The less the roughness, the better the fit.

  As shown in Table 1, Examples 1 and 2 had a lower diffusion rate (liquid spreading) than Comparative Examples 1 and 2, and good results were obtained for other evaluation items. On the other hand, Comparative Example 1 is inferior in diffusivity (liquid spreading) mainly because there is no difference in the contact angle of the constituent fibers between the front surface layer and the back surface layer, and the liquid easily spreads in the surface layer, and the liquid moves downward. There is a problem that it is difficult. Further, in Comparative Example 2, there is mainly no difference in the amount of fibers between the flange portion and the groove portion of the top sheet, and the flange portion is not continuously formed so as to extend in the longitudinal direction of the sheet (the longitudinal direction). Therefore, the results were inferior to those of the examples in terms of liquid spreading and stickiness.

FIG. 1 is a plan view showing a skin contact surface side (surface sheet side) of a cage sheet according to the first embodiment of the present invention. FIG. 2 is a schematic diagram of a cross section taken along line II in FIG. FIG. 3 is a perspective view schematically showing an enlarged main part of the top sheet used for the cage sheet shown in FIG. FIG. 4 is a schematic diagram of a cross section taken along line II-II in FIG. FIG. 5 is a view corresponding to FIG. 4 of another embodiment of the present invention. FIG. 6 is an enlarged perspective view (corresponding to FIG. 4) schematically showing an essential part of the top sheet used in the cage sheet according to the second embodiment of the present invention. FIG. 7 is a schematic diagram of a cross section taken along line II-II in FIG. FIG. 8 is a schematic view showing an example of an apparatus for producing the top sheet shown in FIG. FIG. 9 is a perspective view showing the uneven shaping belt in FIG. 10A and 10B are schematic views showing the manufacturing process of the surface sheet using the apparatus shown in FIG. 8, FIG. 10A is an enlarged cross-sectional schematic view of FIG. 8A, and FIG. 10B is FIG. FIG. 10C is an enlarged schematic cross-sectional view at C in FIG. 8. FIG. 11 is a schematic view showing an example of an apparatus for producing the top sheet shown in FIG. FIG. 12 is a perspective view showing the concavo-convex shaping belt in FIG. 11. 13A and 13B are schematic views showing the manufacturing process of the top sheet using the apparatus shown in FIG. 11, FIG. 13A is an enlarged schematic cross-sectional view in A of FIG. 11, and FIG. 13B is B in FIG. FIG. 13C is an enlarged cross-sectional schematic diagram at C in FIG. 11. FIG. 14 is a diagram for explaining a method for measuring the contact angle, and FIGS. 14A and 14B are diagrams in which the contact angle is preferably measured. In addition, (a ') and (b') are figures which show the fiber after the droplet on a fiber evaporates, and are used in order to measure the tangent of the fiber surface in a boundary part with a water droplet.

Explanation of symbols

1 Origami sheet (absorbent article)
DESCRIPTION OF SYMBOLS 10 Top sheet 10A Front surface layer 10B Back surface layer 10C Middle layer 11 Back surface sheet 15 Seal part 20 Gutter part 21 Gutter top part 30 Groove part 31 Opening

Claims (2)

In a vertically long absorbent article having a surface sheet on the skin contact surface side and a back sheet on the non-skin contact surface side,
The top sheet is composed of a non-woven fabric having alternately ridges and grooves extending in the longitudinal direction of the absorbent article, and the buttock is substantially higher in fiber content than the groove, and is in contact with the skin. A surface layer constituting a surface , a back layer disposed closest to the back sheet, and an intermediate layer disposed between the surface layer and the back layer, and has a three-layer structure as a whole. And the hydrophilicity of the surface layer and the hydrophilicity of the intermediate layer are substantially the same,
The surface layer has a lower hydrophilicity than the back surface layer, is curved convexly on the skin contact surface side in the heel portion, and is concavely curved on the skin contact surface side in the groove portion,
The contact angle of the constituent fibers of the surface layer is 60 to 85 °,
The constituent fibers of the back layer are mainly oriented in the thickness direction of the back layer ,
The orientation angle in the thickness direction of the constituent fibers of the surface sheet increases in the order of the surface layer, the intermediate layer, and the back layer, the orientation angle of the surface layer is 0 to 30 °, and the orientation of the intermediate layer The angle is 5 to 110 °, the orientation angle of the back layer is 45 to 120 °,
The skin contact surface side of the intermediate layer has a corrugated shape along the width direction of the absorbent article due to the formation of unevenness, and the unevenness is substantially formed on the non-skin contact surface side of the intermediate layer. Absorbent article that is flat and not flat . The absorbent article of the surface layer according to claim 1 Symbol placement has an opening into the groove.

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