JP2009297048A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article which has soft texture so as to give an excellent wearing feeling to a wearer and is excellent in adhesion to the excretion part of the body. <P>SOLUTION: A surface sheet 10 comprises a nonwoven fabric alternately having ridge parts 20 and groove parts 30 extending in the longitudinal direction of the article 1. On the skin abutting surface side of the surface sheet 10, a pair of linear grooves 60 formed by integrating the surface sheet 10 and an absorbent body 12 by pressure bonding are formed. The linear groove 60 has a center part 60A extending in the longitudinal direction of the article 1, and a front end part 60B and a rear end part 60C from respective front and rear ends in the longitudinal direction of the center part 60A to the inner part of the article 1. The absorbent body 12 has a low rigidity area 12A and a high rigidity area 12B positioned at the center part in the width direction of the article 1, and the linear groove 60 is formed in the low rigidity area 12A. The low rigidity area 12A is present between the pair of linear grooves 60 and the high rigidity area 12B is present more on the outer part in the width direction of the article 1 than the pair of center parts 60A and 60A. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to absorbent articles such as sanitary napkins and panty liners.

  Conventionally, bodily fluid absorbent articles such as sanitary napkins and panty liners are composed of a liquid-permeable top sheet, a liquid-impervious back sheet, and a liquid-absorbent core interposed between the two sheets. As the surface sheet, a nonwoven fabric or a perforated synthetic resin film is used. And the proposal which improves absorptivity is made | formed by using what gave various shapes, such as a hole sheet which has a liquid introduction pipe | tube, and a sheet | seat which has a grooved structure as a surface sheet. For example, in Patent Document 1, as the top sheet, a plurality of concave portions and convex portions that continuously undulate in the width direction of the liquid absorbent core and extend in the longitudinal direction of the liquid absorbent core are formed. A bodily fluid treatment article employing a top sheet is described.

  Moreover, in the bodily fluid absorptive article, the proposal which improves the adhesiveness with respect to the excretion part of a body is made | formed. For example, Patent Literature 2 includes a central absorbent portion, support portions disposed on both the left and right sides of the central absorbent portion, and side end portions disposed on the outer side in the article width direction of the support portion. An absorbent article is described in which the central absorbent portion and the support portion can be bent via a flexible shaft, and the support portion and the side end portion can be bent via a second flexible shaft. Has been. Further, in Patent Document 3, a pair of compression grooves that are compressed from the skin side surface toward the clothing side surface are formed on the left and right sides so as to be depressed in the vertical direction, and the liquid absorption layer is formed on the liquid absorption layer. A flexible portion that is recessed from the clothing side surface toward the skin side surface is provided, and the flexible portion starts from a position away from a lateral reference line that bisects the article in the longitudinal direction. There is described an absorbent article that extends toward the end edge of the flexible member and at least a part of the flexible portion is positioned between the pair of compressed grooves.

JP-A-11-342154 JP 2004-154153 A JP 2004-208919 A

  Although the bodily fluid treatment article described in Patent Document 1 employs a medium-high structure for the absorbent body, it is difficult to obtain flexibility due to its high rigidity. There was a room for improvement in terms of adhesion to the excretion part because gaps were likely to occur. Moreover, since the said convex part in the bodily fluid processed article of patent document 1 is a hollow structure, it was crushed easily especially in the middle-high structure part which became easy to receive the pressure at the time of wear, and the cushioning property was poor.

  The absorbent articles described in Patent Documents 2 and 3 have the above-described configuration, so that when the pressure from the wearer's thigh is applied during wearing, the central absorbent part (Patent Document 2) or the compressed groove Since the part (patent document 3) pinched | interposed into a wearer is pressed toward a wearer's excretion part, it is supposed that it is excellent in the adhesiveness with respect to an excretion part. However, in the absorbent articles described in Patent Documents 2 and 3, the left and right side parts of the portion (the center part in the width direction of the article) pressed toward the excretion part of the wearer are caused by pressure from the wearer's thigh. It was easy to deform, and for this reason, the pressing of the part against the excretion part was insufficient, and it was difficult to say that the adhesion was sufficient.

  An object of the present invention is to provide an absorbent article that is soft to the touch, can give the wearer an excellent feeling of wear, and has excellent adhesion to the excretory part of the body.

  The present invention relates to a vertically long absorbent article having a top sheet on the skin contact surface side, a back sheet on the non-skin contact surface side, and an absorbent body between the two sheets. It consists of a nonwoven fabric having alternating ridges and grooves extending in the longitudinal direction, and the amount of fibers in the ridge is substantially larger than that of the grooves, and on the skin contact surface side of the surface sheet, A pair of linear grooves formed by integrating the topsheet and the absorbent body by pressure bonding are formed, and each of the pair of linear grooves includes a central portion extending in the longitudinal direction of the absorbent article, A front end portion and a rear end portion facing inward of the absorbent article from the longitudinal front and rear ends of the central portion, respectively, and the absorber is a low-rigidity region located in the widthwise central portion of the absorbent article; A high-rigidity region having higher rigidity than the low-rigidity region, and a pair of front The linear groove is formed in the low-rigidity region, the low-rigidity region exists between the pair of linear grooves, and the width of the absorbent article is larger than the central portion of the pair of linear grooves. The object is achieved by providing an absorbent article in which the high-rigidity region exists outside in the direction.

  The absorbent article of the present invention is soft to the touch, can give the wearer an excellent feeling of wear, and has excellent adhesion to the excretory part of the body.

  Hereinafter, the absorptive article of the present invention is explained based on the desirable embodiment with reference to drawings. The top view which looked at the sanitary napkin which is one Embodiment of the absorbent article of this invention from the surface sheet side is shown by FIG. FIG. 2 is a diagram schematically showing a cross section taken along line II in FIG.

  As shown in FIG. 1, the napkin 1 of the present embodiment has a vertically long shape in plan view. The napkin 1 includes a top sheet 10 positioned on the skin contact surface side, a back sheet 11 positioned on the non-skin contact surface side, and an absorbent body 12 interposed between the two sheets 10 and 11. The absorber 12 has a vertically long shape in plan view. The top sheet 10 and the back sheet 11 respectively extend outward from the front and rear end edges and the left and right side edges of the absorbent body 12, and the both extended sheets 10 and 11 are joined by a bonding means such as an adhesive or heat seal. They are fixed to each other. In addition, an adhesive portion (not shown) for fixing the napkin 1 to the underwear extends in the longitudinal direction of the napkin 1 on the non-skin contact surface in the center region in the width direction of the napkin 1, that is, the surface of the back sheet 11. It is formed as follows.

  The napkin 1 has the excretion part opposing part A arrange | positioned facing a wearer's excretion part at the time of wear. Furthermore, it has the front part B and the back part C which are extended in the front-back direction from the excretion part opposing part A. The front part B is arranged closer to the abdomen (front) of the wearer than the excretory part facing part A. The rear part C is arranged on the back side (rear) of the wearer rather than the excretory part facing part A. The excretory part opposing part A in this embodiment is located in the longitudinal direction center part of the napkin 1. FIG.

  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. 5 shows an enlarged view of a main part of the top sheet 10. 6 is a cross-sectional view taken along line II-II in FIG. In FIG. 5, the direction indicated by Y is the longitudinal direction of the napkin 1, and the direction indicated by X is the width direction of the napkin 1. The top sheet 10 shown in FIGS. 5 and 6 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 sanitary napkin and a disposable diaper. The 2nd surface 10b is a surface which faces the absorber side of an absorbent article. The top sheet 10 is made of a nonwoven fabric having alternately ridges 20 and grooves 30 extending in the longitudinal direction Y of the napkin 1. 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.

  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, a portion of the groove portion 30 where an opening 31 described later is not formed is filled with constituent fibers of the topsheet 10. However, as will be described later, 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. 6, 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.

  On the other hand, the second surface 10b side has a contour that draws a smooth and gentle curve convex downward. Therefore, the site | part located in the collar part 20 among the absorber opposing surfaces of the surface sheet 10 comes in contact with the absorber 12 distribute | arranged under the surface sheet 10 by a surface. As a result, the liquid excreted in the topsheet 10 can pass through the flange 20 in the topsheet 10 and smoothly migrate to the absorber 12. As a result, the first surface 10a of the topsheet 10 has a smooth and dry feeling.

  The shape of the collar portion 20 is not limited to the above-described shape. For example, as shown in FIG. 7A, the second surface 10b side has a contour that draws a smooth and gentle curve upward. Alternatively, as shown in FIG. 7B, the second surface 10b side may be flat. Such a difference in shape mainly depends on the manufacturing conditions of the topsheet 10.

  As shown in FIG. 6, 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 flange portion 20 has substantially the same thickness at the top portion 21 at any position in the extending direction (in FIG. 6, the direction orthogonal to the paper surface). In the topsheet 10 of the present embodiment, there is no clear boundary between the flange portion 20 and the groove portion 30, and in general, a portion having the smallest substantial thickness located between the two top portions 21 adjacent to each other in the X direction and A portion in the vicinity thereof becomes the groove 30. When there is a clear boundary between the flange 20 and the groove 30, for example, as shown in FIG. 6, the cross-sectional curve shape at the flange 20 in a cross-sectional view in the direction perpendicular to the extending direction of the flange 20. However, when the change in the cross-sectional shape is clear, such as when the groove part 30 has a linear cross-sectional shape, the change point can be used as the boundary part between the flange part 20 and the groove part 30, but the boundary between the flange part 20 and the groove part 30 Is defined more clearly as a boundary portion between the flange portion 20 and the groove portion 30 at the position of the apparent thickness at the top portion 21 of the flange portion 20.

  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. 6) 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 the present embodiment, the flange portion 20 and the groove portion 30 are formed with the same width. However, the present invention is not limited to this. For example, the width of the flange portion 20 in the central region in the X direction of the topsheet 10 is set to the flange portion in the side region. The width may be wider than 20. 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. Moreover, when the substantial thickness of the collar part 20 is thinner than the apparent thickness, specifically, when it is 90% or less, even when the napkin 1 is deformed into a curved shape when the napkin 1 is used, It is possible to prevent a gap generated between the absorber 12 and the absorber 12 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. By forming the flange portion 20 and the groove portion 30 in this manner, the flange portion 20 can be deformed flexibly while being hardly crushed. That is, when the napkin 1 is worn, a part of the absorbent body 12 (the center in the width direction) is raised by the external force applied from the width direction by the wearer's thigh, which causes the deformation of the topsheet 10. At this time, the surface sheet 10 has the ribs 20 positioned on both sides of the surface sheet 10 outward while slightly extending the individual groove portions 30 with a relatively small amount of fiber (basis weight is relatively small) in the width direction. Deforms to open. The surface sheet 10 that deforms in this way follows uplift of the absorbent body 12 without slightly closing the opening 31 to be described later in the groove 30, but rather slightly widening the opening 31 and without deforming the flange 20. be able to. Therefore, the topsheet 10 can be flexibly deformed without crushing the collar portion 20 as much as possible while maintaining and improving the absorbability by 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 150 g / m ² , particularly preferably 40 to 100 g / m ² . On the other hand, the basis weight of the groove part 30 (except for the opening 31 described later) is preferably 10 to 70 g / m ² , particularly preferably 15 to 50 g / m ² . The basis weight as a whole of the top sheet 10 (including the opening 31) is preferably 20 to 80 g / m ² , particularly preferably 30 to 80 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. When the width of the opening 31 and the width of the groove 30 are approximately the same, the boundary between the flange 20 and the groove 30 is determined by the position when a plurality of end portions in the width direction of the opening 31 are viewed in series. When the width of the groove portion 30 is wider than the width of the opening 31, the inflection point is set as a reference point (priority) based on the cross-sectional shape of the topsheet 10 to be measured, as in the case of apparent thickness measurement. The reference position is the tilt position of °. 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 obtained by obtaining a difference between the weight of the top sheet 10 before cutting and the weight of the flange part 20 and further subtracting the area corresponding to the opening 31. Since calculation of the basic weight of the groove part 30 requires the area of the groove part 30 including the opening 31 and the area of the opening 31, it is measured using an image analysis device or the like described later.

Further, the flange portion 20 has a fiber density at the top portion 21 that is different from the fiber density of the groove portion 30, particularly the fiber density at the end portion of the opening 31. In detail, compared with the top part 21 of the collar part 20, the groove part 30, especially the edge part of the opening hole 31, is made high in fiber density. As a result, the liquid from the wearer is easily guided from the top portion 21 of the flange portion 20 to the end portion of the opening 31 of the groove portion 30. The fiber density at the top portion 21 of the flange portion 20 is preferably 0.01 to 0.1 g / cm ³ , and the fiber density at the end of the opening 31 is 0.05 to 0.5 g / cm ^3. preferable. The fiber density of each part is measured by the following method. First, the density of the collar 20 is calculated from the apparent thickness and basis weight. Next, the cut surface of the surface sheet 10 is enlarged and observed using an electron microscope (150 to 500 times), and the area of the portion including the 10 cross-sections of the fibers (the area where the outer surfaces of the outermost fibers are connected by straight lines) Measurement is performed at the ends of the flange portion 20 and the opening 31 using an image analysis device described later. Using these measured values and the value of the fiber density of the collar portion 20 calculated previously, the fiber density of the end portion of the opening 31 is calculated by proportional calculation. The fiber density is higher as the area occupied by the area including 10 cross sections of the fiber is lower.

  As shown in FIG. 5, a large number of apertures 31 are formed in the groove 30. The apertures 31 are regularly formed at regular intervals along the direction in which the groove 30 extends. Accordingly, the top sheet 10 has a row of holes formed of a large number of apertures 31 arranged at regular intervals along the Y direction (longitudinal direction of the napkin 1). 1 in the width direction of 1). The pitch of the arrangement of the apertures 31 in all the aperture rows is the same. In two adjacent rows of apertures, the apertures 31 are located at the same position in the X direction of the topsheet 10. The opening 31 is arranged so that there is always a portion where the opening 31 is not formed when the entire sheet is viewed along the X direction of the sheet 10. Further, when viewed from the top sheet 10 as a whole, the apertures 31 are distributed and arranged so as to form a multi-row row in the X direction of the sheet 10 and a multi-row row also 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 separating the constituent fibers of the topsheet 10. 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 topsheet 10. 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 top sheet 10 in plan view from the viewpoint of liquid permeability and maintaining the strength of the top sheet 10. 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 lens mount connection] and video board [Spectra 3200; manufactured by Canopus Co., Ltd.] take in. The captured image is binarized by the image analysis software NEW QUEBE (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.

  The opening 31 may have an end projecting toward the second surface 10b of the topsheet 10 to form a liquid introduction pipe including the projecting portion. As described above, since the end portion of the opening 31 has low rigidity, the cushioning property of the topsheet 10 is further enhanced by forming the protruding portion. Moreover, since the contact between the topsheet 10 and the absorbent body 12 can be maintained regardless of the structure of the absorbent body 12 located below the topsheet 10 by forming the protruding portion, the liquid excreted from the wearer Is efficiently transmitted from the top sheet 10 to the absorber 12.

  As shown in FIGS. 1 and 2, a pair of linear grooves 60 and 60 are formed on the skin contact surface side of the topsheet 10, in which the topsheet 10 and the absorber 12 are integrally formed by pressure bonding. ing. The linear grooves 60 are formed in the left and right side regions in the width direction of the napkin 1 so as to extend in the longitudinal direction of the napkin 1. The pair of linear grooves 60, 60 are formed at symmetrical positions with a virtual center line (not shown) that bisects the napkin 1 in the width direction. The linear groove 60 exists in the excretion part facing part A, and further extends to a part of each of the front part B and the rear part C located before and after the excretion part facing part A. The linear groove | channel 60 is formed by compressing the surface sheet 10 and the absorber 12 from the skin contact surface side with or without heat. This compression can be performed using an embossing device known in the art. The pair of linear grooves 60, 60 will be described later in addition to the side leakage preventing effect by inducing the diffusion of the excreted body fluid in the longitudinal direction of the napkin 1 and suppressing the diffusion of the body fluid in the width direction. There is an effect of promoting the formation of a raised portion.

  Each of the pair of linear grooves 60, 60 includes a central portion 60A extending in the longitudinal direction of the napkin 1, and a front end portion 60B and a rear end portion 60C that are directed inward of the napkin 1 from the longitudinal front and rear ends of the central portion 60A. And have. In the present embodiment, the central portion 60 </ b> A exists at least in the excretory portion facing portion A, and has a linear shape substantially parallel to the longitudinal direction of the napkin 1 in a plan view of the napkin 1. The central portion 60 </ b> A has a substantially parallel positional relationship with the flange portion 20 of the topsheet 10. As shown in FIG. 1, the front end portion 60B extends obliquely forward on the inward side of the napkin 1 from the longitudinal front end of the central portion 60A, and protrudes outward of the napkin 1 in plan view. It has an arcuate shape that curves. The rear end portion 60C extends from the rear end in the longitudinal direction of the central portion 60A toward the oblique rear side on the inner side of the napkin 1, and has an arc shape that curves convexly toward the outer side of the napkin 1 in plan view. have. Between the longitudinal direction front end part and the front end part 60B of the central part 60A and between the longitudinal direction rear end part and the rear end part 60C of the central part 60A, respectively, the linear groove 60 is a continuous strip. It is a groove. The linear groove 60 is formed in a substantially U shape as a whole.

  The shape of the front end portion 60B and the rear end portion 60C in plan view is not limited to the arc shape as shown in FIG. 1, but is, for example, a linear shape substantially parallel to the width direction of the napkin 1 as shown in FIG. May be. The linear groove 60 shown in FIG. 4A is different from the linear groove 60 shown in FIG. 1 that includes a curved line in that it is formed of only a straight line. It is the same in that it is formed in a U shape.

  Thus, when a pair of substantially U-shaped linear grooves 60, 60 are formed in plan view, when the napkin 1 is worn, the napkin is subjected to a compressive force or the like by the wearer's thigh. The rising of the absorber 12 in the central region of 1 is promoted and it is possible to maintain the raised state. The specific relationship between the linear groove 60 and the bulge of the absorbent body 12 is presumed to be mainly due to two factors 1) and 2) described below. In the following, in explaining these two factors, the linear groove 60 formed only from the straight line shown in FIG. 4A is described as an example for the purpose of easy explanation. The description using 4 also applies to a linear groove including a straight line and a curved line, such as the linear groove 60 shown in FIG.

  The factor 1) is because a bulge-inducing moment acts on each of the front end portion 60B and the rear end portion 60C of the linear groove 60. FIG. 4B shows an explanatory diagram of the bulge-inducing moment and the phenomenon that occurs in association with the bulge-inducing moment. In FIG.4 (b), the code | symbol F1 has shown the compressive force received from a wearer's thigh etc. in a napkin. The compressive force F1 acts inward from both ends of the napkin in the width direction and substantially parallel to the skin contact surface of the napkin. The linear groove front and rear end portions 60B and 60C having a certain degree of rigidity with respect to the compression force F1 generate a force to rotate the absorber 12 toward the standing state, that is, a moment F2. The moment F2 acts as a moment that promotes the uplift of the central region of the napkin 1 sandwiched between the pair of linear grooves 60, 60, particularly the central region of the napkin 1 sandwiched between the pair of central portions 60A, 60A. From the standpoint of its effect, it should be called a bulge-induced moment. The occurrence of the bulge-inducing moment F2 eases the deformation of the absorber 12 in a so-called twisted manner, as well as from the viewpoint that the compressive force F1 is used to promote the bulge. It is also preferable from the viewpoint of.

  The factor 2) is because the raised holding force acts on the front end portion 60B and the rear end portion 60C of the linear groove 60. FIG. 4 (c) shows an explanatory diagram of the bulge holding force and a phenomenon that occurs in association with the bulge holding force. In the central region of the napkin 1 sandwiched between the pair of linear grooves 60, 60 once raised by the above-described uplift-inducing moment, a force (lifting up) is applied to the uplift by wearing pressure or a seating motion of the wearer. Stopping force) F3 works downward in a direction perpendicular to the skin contact surface of the napkin 1. A resistance F4 acting upward in a direction perpendicular to the skin contact surface of the napkin 1 is generated at the front and rear ends 60B and 60C of the linear groove having a certain degree of rigidity against the bulge prevention force F3. When this resistance F4 is the same as or larger than F3, the crushing of the bulge can be completely suppressed. Further, when the drag force F4 is smaller than the bulge prevention force F3, the bulge of the bulge cannot be completely suppressed, but the crushed can be reduced. Thus, the drag force F4 is a force that can maintain the raised state, and it should also be referred to as a raised holding force from the viewpoint of its effect. With this raised holding force F4, the central region of the napkin 1 sandwiched between the pair of linear grooves 60, 60 once raised can be stably raised.

  The above-described bulge-inducing moment and bulge holding force are not significantly affected by the shapes of the front end portion 60B and the rear end portion 60C in plan view, and even if the shape is an arc shape as shown in FIG. Occurs in the same manner as in the case of a straight line as shown in FIG. However, as shown in FIG. 1, the linear groove 60 preferably has a curved shape in which the front and rear end portions (60B, 60C) in the longitudinal direction are curved in the plan view of the napkin 1. This is mainly due to the following reasons. That is, when the front and rear end portions in the longitudinal direction of the linear groove 60 have curved shapes, when the napkin 1 is worn, the absorbent body 12 is deformed by the pressure from the width direction and a part thereof is raised. In addition, it is difficult to form an extreme step at the boundary between the raised portion and the non-lifted portion, and the shape becomes gradual, which contributes to an improvement in wearing feeling and prevention of a gap between the napkin and the skin.

  The linear groove 60 is not limited to the one in which the crimping portion between the topsheet 10 and the absorber 12 is continuous over the entire linear groove 60, and the crimping portion is discontinuously arranged. It is sufficient that the pressure-bonding portion is substantially continuous and forms a single groove as a whole. In the linear groove 60 in which the crimp parts are discontinuously arranged, there is a non-crimp part where the topsheet 10 and the absorbent body 12 are not crimped between adjacent crimp parts. In the linear groove 60 in which the crimp parts are discontinuously arranged, the interval between adjacent crimp parts (the length along the length direction of the linear groove 60 of the non-crimp part) is preferably 0.5 to. 3.0 mm.

  The width of the linear groove 60 is preferably 0.5 to 6.0 mm, more preferably 0.8 to 4 from the viewpoints of ease of the absorber 12 to be raised, retention of the raised state, and leakage prevention. 0.0 mm. The central portion 60A, the front end portion 60B, and the rear end portion 60C may have the same or different widths. Further, the width of the linear groove 60, in particular, the width of the central portion 60A is preferably substantially equal to the width of the flange portion 20, or preferably narrower than that. Thereby, it is possible to minimize the influence of crushing the flange portion 20 due to the formation of the linear groove 60 or its central portion 60A.

  As shown in FIGS. 1 and 2, the absorbent body 12 has a low-rigidity region 12A located at the center in the width direction of the napkin 1 and a high-rigidity region 12B having a higher rigidity than the low-rigidity region 12A. Yes. In the present embodiment, the entire area of the absorbent body 12 in the width direction central portion is the low-rigidity region 12A, and the entire side region located on the left and right sides of the width-direction central portion is the high-rigidity region 12B. The rigidity in the present invention means the hardness of an object (predetermined region of the absorber) and can be regarded as the magnitude of an external force necessary to cause the object to generate a displacement such as a predetermined bending or twisting. . The level of rigidity of the two areas to be compared can be determined by using a measurement value such as a stiffness measurement method described later.

  The rigidity as used in the present invention is measured as follows. In the present specification, when the rigidity is indicated by a numerical value, unless otherwise specified, the rigidity value measured by the following method is indicated. Daiei Kagaku Seisaku Seisakusho Co., Ltd., which conforms to the stiffness measurement method specified in JIS L1096 (General Textile Test Method) in a test room with a temperature of 23 ° C. and a humidity of 50%, uses a handometer tester. . The test piece is placed on a sample table adjusted to 20 mm between the slots so that the measurement site of the test piece is located at the center between the slots and the length of the test piece along the longitudinal direction of the absorber is parallel to the slot. It is arranged horizontally so that it coincides with the direction. In addition, it arrange | positions so that the both ends in the width direction of a test piece may be mounted on the test stand 5 mm or more. Do not fix the specimen on the sample stage. A blade adjusted so as to descend to a position (lowermost position) 8 mm below the surface of the sample stage is lowered at a constant speed (200 mm / min) from above the test piece. Then, the maximum value (cN) indicated by the indicator (load meter) when the test piece is pressed back and forth in the length direction is read. The measurement is performed 5 times, and the average value is calculated as the stiffness value.

  In addition, about a test piece, it takes out so that an absorber may not be damaged from the absorbent article left at room temperature without carrying out preliminary drying especially, width (direction orthogonal to a product longitudinal direction) 30 mm or more, length (product) (Longitudinal direction) Cut to 150 mm, and this is used as a test piece. In this case, it is preferable to eliminate materials other than the absorber as much as possible, but in order not to damage the absorber, the absorber is a part of the top sheet, a part of the back sheet, or an adhesive for joining the top sheet and the back sheet. The agent may be partially attached. Further, the absorber can be measured if its length is 30 mm or more (between slots: 20 mm + both ends: 5 mm each). Therefore, it is possible to use the test piece as it is in the form of the product. However, if a surface sheet having different rigidity is attached depending on the sample to be measured, the reliability of the measured value may be impaired. Therefore, it is preferable to perform measurement after removing the top sheet.

  In the absorbent body 12, the rigidity in the low rigidity region 12A is preferably 5 to 100 gf, more preferably 10 to 50 gf, and the rigidity in the high rigidity region 12B is preferably 15 to 200 gf, more preferably 30 to 100 gf. is there. Further, the ratio of the rigidity (the rigidity value of the low rigidity area / the rigidity value of the high rigidity area) is preferably 0.1 to 0.9, more preferably 0.2 to 0.8. If there is a difference in rigidity between the low-rigidity region 12A and the high-rigidity region 12B, when the absorbent body 12 receives pressure from the width direction when the napkin 1 is worn, the deformation of the absorbent body 12 is low-rigidity as described later. Since the process is preferentially started from the region 12A, the predetermined effect of the present invention can be obtained, and if this rigidity difference is large, a more preferable effect can be obtained.

  In general, since there is a correlation between density (for example, fiber density or apparent density of pulp fiber) and rigidity in the same material, in the present invention, the rigidity of different parts in the absorbent body is high or low. As one of the methods for determining the density, a calibration curve of density vs. stiffness can be determined and stiffness estimation by density can be used. For example, it is possible to determine whether the rigidity is high or low based on a difference in thickness between two contrasted portions measured from a photomicrograph of a cross section of the absorber, that is, a difference in density. Usually, a relatively high density portion is a low rigidity region having low rigidity, and a relatively low density portion is a high rigidity region having high rigidity. Therefore, the low rigidity region according to the present invention can be regarded as a low density region, and the high rigidity region according to the present invention can be regarded as a high density region.

  The density of each site | part in an absorber is shown with the value of the apparent density calculated from the apparent thickness and basic weight of the said site | part. If it is difficult to measure due to the structure of the part being broken and the thickness of the constituent fibers changing due to cutting, such as when the part is uniformly embossed, Numerical values based on proportional calculation using an image analysis apparatus can also be used.

  The absorber 12 having such rigidity (density) distribution can be formed by, for example, uniformly embossing a part of the precursor of the absorber 12 having substantially uniform rigidity. The “absorber precursor” herein is substantially the same as the absorber 12 except that the rigidity is substantially uniform throughout and does not include the above-described high-rigidity region and low-rigidity region. That is, the absorber 12 is obtained by giving a rigidity (density) distribution to the precursor of the absorber 12 by a predetermined means. Usually, the absorber in this type of absorbent article has substantially uniform rigidity, and the “absorber precursor” can be produced in the same manner as the absorber in this type of absorbent article.

  In the precursor of the absorbent body 12, a portion where the embossing process is uniformly performed is a high-rigidity region 12B, and a region where the embossing process is not performed is a low-rigidity region 12A. Such an embossing process can be performed as follows, for example. First, the raw materials of the absorber are laminated to form a laminate, and then the embossed convex portions are regularly arranged on the peripheral surface so that the non-skin contact surface side of the laminate is subjected to an embossing treatment. The embossing roll is sent to an embossing apparatus having an embossing roll and an anvil roll disposed opposite to the embossing roll. In the embossing process, it is preferable to adjust the distance between the embossing roll and the anvil roll, that is, the height of the embossing convex portion, for the purpose of controlling the rigidity.

  The pair of linear grooves 60, 60 described above is formed in the low rigidity region 12A as shown in FIG. The central portion 60A of the linear groove 60 is preferably located at substantially the same position as the side edge of the low-rigidity region 12A, and specifically, within 10 mm from the side edge along the longitudinal direction of the low-rigidity region 12A. It is preferable from the viewpoint of maintaining the raised shape of the absorbent body 12 when the absorbent body 12 receives pressure from the width direction during wearing.

  In the present embodiment, a low-rigidity region 12A exists between the pair of linear grooves 60, 60, and the rigidity is higher outward in the width direction of the napkin 1 than the central portion 60A of the pair of linear grooves 60, 60. Region 12B exists. Thus, the pair of linear grooves 60, 60 formed in the low-rigidity region 12 </ b> A of the absorbent body 12, with the central portions 60 </ b> A and 60 </ b> A (parts extending in the longitudinal direction of the napkin 1 in the linear grooves 60) as a boundary. A part (both sides) of the absorbent body 12 positioned on the outer side in the width direction of the napkin 1 with respect to the central portions 60A and 60A is defined as a high-rigidity region 12B, and the napkin 1 in the width direction with respect to the pair of central portions 60A and 60A When the napkin 1 is worn, the napkin 1 is compressed from the width direction by the wearer's thigh when the napkin 1 is worn. 4 (b)), the low-rigidity region 12A sandwiched between the pair of linear grooves 60, 60 (the central portion in the width direction of the excretory part-facing part A) is worn as shown in FIG. This bulge and body rise toward the skin side of the person Adhesion to the excretory part is increased.

  In particular, when both side portions of the absorbent body 12 that are directly subjected to the compressive force by the wearer's thigh are highly rigid (high density) as described above, the both side portions are deformed by the compressive force. Since it is difficult, the compressive force is transmitted to the pair of linear grooves 60 and 60 without being relaxed. As described above, the compression force transmitted to the pair of linear grooves 60, 60 via the both side portions (high-rigidity region 12B) is substantially U-shaped when the pair of linear grooves 60, 60 are viewed in plan, respectively. By being formed in a shape, the low-rigidity region 12A is preferentially used as a force for raising (lifting-inducing moment), and the deformation of the low-rigidity region 12A that is crushed in a so-called twisted shape is relieved. The compressive force generated mainly by the user's legs is transmitted through the high-rigidity region 12B to the low-rigidity region 12A located more inward while being dispersed in a fan-shaped manner along the body shape. If the central portion 60A of the linear groove 60 is disposed in the high-rigidity region 12B, the central portion 60A directly receives this compressive force. Therefore, the central portion 60A has a partially different compressive force. As a result, the linear groove 60 is curved. Although it is possible to prevent the linear groove 60 from being curved depending on the thickness of the linear groove, the above-described advantages are easily lost. On the other hand, when the central portion 60A of the linear groove 60 is formed in the low rigidity region 12A as in the present embodiment, the low rigidity region 12A located between the high rigidity region 12B and the linear groove 60 is provided. Since it acts as a buffer area for equalizing the compressive force, it is difficult to bend the central portion 60A of the linear groove 60 when receiving the compressive force, and the deformation of the low-rigidity region 12A can be suppressed as much as possible. Further, since the linear groove 60 is formed in the low-rigidity (low-density) region 12A as described above, the linear groove 60 itself exists as a region that is more dense and difficult to deform than the low-rigidity region 12A. As a result, when the compressive force is applied, the linear groove 60 itself is raised without being deformed. By the bulging of the linear groove 60, the bulging of the portion surrounded by the linear grooves 60, 60 is further promoted.

  The length of the low-rigidity region 12A along the longitudinal direction of the absorbent body 12 (napkin 1) is preferably 20 to 100%, more preferably 30 to 70% with respect to the longitudinal length of the absorbent body 12. Yes (100% in this embodiment). Moreover, it is preferable that the low-rigidity region 12A exists at least in the excretion portion facing portion A. The length W1 (see FIG. 2) along the width direction of the absorber 12 (napkin 1) in the low-rigidity region 12A is the length in the width direction of the absorber 12 (when the width of the absorber 12 is not constant). The width of the portion having the maximum width is preferably 10 to 80%, more preferably 20 to 60%.

  The length W2 (see FIG. 2) along the width direction of the absorbent body 12 (the napkin 1) of the high-rigidity region 12B located more outward in the width direction of the napkin 1 than the pair of central portions 60A, 60A is the absorbent body. Preferably, it is 10 to 45% on each of the left and right sides, more preferably 20 to 40% on each of the left and right sides with respect to the length in the width direction of 12. The region other than the low rigidity region 12A in the absorbent body 12 is preferably a high rigidity region 12B. Further, the low rigidity region 12A is preferably located at the center in the direction along the width direction of the absorbent body 12 (napkin 1), that is, the value of W2 is preferably substantially the same on the left and right.

The basis weight of the absorbent body 12 is preferably 100 to 600 g / cm ² , more preferably 150 to 400 g / cm ² . The low-rigidity region 12A and the high-rigidity region 12B may have the same basis weight or may be different from each other. As an example of the case where the basis weights of the low-rigidity region 12A and the high-rigidity region 12B are different, the basis weight of a part or the entire area of the low-rigidity region 12A is made smaller than the basis weight of the high-rigidity region 12B. The form to which the density difference of 12A of area | regions and the highly rigid area | region 12B was provided is mentioned. Increasing the difference in rigidity between different parts of the absorbent body 12 by controlling the basis weight as described above means that the raised portion (the raised low-rigidity region 12A located at the center in the width direction of the excretory part-facing part A). It is effective in promoting the formation of

  The thickness of the low rigidity region 12A under no load (the thickness of the portion where the linear groove 60 is not formed) is preferably 1.5 to 15.0 mm, more preferably 3.0 to 10.0 mm. The thickness of the high-rigidity region 12B under no load is preferably 1.0 to 8.0 mm, and more preferably 1.0 to 5.0 mm.

  The low-rigidity region 12A and the high-rigidity region 12B may have the same thickness or different from each other. As an example of the case where the thickness is different between the low rigidity region 12A and the high rigidity region 12B, the thickness of a part or the entire region of the low rigidity region 12A is made larger than the thickness of the high rigidity region 12B, and the low rigidity region 12A By projecting a part or the whole of the skin to the skin contact surface side (surface sheet 10 side) of the napkin 1, the middle and high portions are formed in the central portion in the width direction of the absorbent body 12 (between the pair of linear grooves 60, 60). The formed form is mentioned. Similar to the control of the basis weight described above, the formation of the middle and high portions by the control of the thickness is effective for promoting the formation of the raised portions.

  Further, from the viewpoint of facilitating the formation of the raised portion and reliably preventing side leakage, the length L1 (see FIG. 1) of the linear groove 60 along the longitudinal direction of the absorber 12 (napkin 1) is The length in the longitudinal direction of the absorbent body 12 is preferably 10 to 90%, and more preferably 20 to 80%. From the same viewpoint, the length L2 (see FIG. 1) along the width direction of the absorber 12 (napkin 1) of each of the front end portion 60B and the rear end portion 60C is the length in the width direction of the absorber 12 (see FIG. 1). When the width of the absorber 12 is not constant, the width is preferably 2 to 30%, more preferably 5 to 15% with respect to the width of the portion having the maximum width.

  It is preferable that the back sheet 11 and the absorber 12 are not joined between the pair of linear grooves 60, 60. With such a configuration, the low-rigidity region 12A can be easily deformed without being constrained by the back sheet 11, thereby further facilitating the formation of the raised portion. Here, “not joined” means that the area between the back sheet 11 and the absorber 12 is in the entire region between the pair of linear grooves 60, 60 (hereinafter also referred to as the inter-linear groove region). Not only when not joined at all, but also due to unintentional adhesion of adhesive during the manufacture of the napkin, etc., part of the region between the linear grooves (preferably 5% or less of the total area of the linear inter-groove region) The case where the back sheet 11 and the absorbent body 12 are joined is included. In the case where the back sheet 11 and the absorber 12 are not joined in the linear inter-groove region, various joints such as an adhesive are used between the back sheet 11 and the absorber 12 in the region other than the linear inter-groove region. It may be joined via a means or may not be joined.

  Moreover, it is preferable that the surface sheet 10 and the absorber 12 are joined via an adhesive between the pair of linear grooves 60, 60. With such a configuration, it is possible to prevent the pressure-bonding portion between the topsheet 10 and the absorbent body 12 constituting the linear groove 60 from being dissociated due to moisture etc. and the rigidity of the linear groove 60 being lowered. The fact that the rigidity of the linear groove 60 is maintained high means that the effect of supporting the entire raised portion is continued when the raised portion is formed when the napkin is worn, thereby making it easier to form the raised portion. Therefore, it is preferable. Here, “bonded” means not only the case where the surface sheet 10 and the absorber 12 are bonded to each other by the adhesive (solid coating) applied to the entire area between the linear grooves. The case where the surface sheet 10 and the absorbent body 12 are joined by an adhesive applied to substantially the entire region of the linear inter-groove region (preferably 5% or more of the total area of the linear inter-groove region). Including. When joining between the surface sheet 10 and the absorber 12 in the said linear groove area | region through an adhesive agent, between the surface sheet 10 and the absorber 12 in area | regions other than this linear groove area is adhesion | attachment. It may be joined via an agent or may not be joined.

  Next, constituent materials and the like of the napkin 1 of the present 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.

  Absorbent body 12 preferably comprises a mixture of wood fluff pulp and superabsorbent hydrogel particles. This mixture may be entirely covered with tissue paper and compressed to the required thickness. Moreover, the middle or high part may be formed by further stacking pulp or a mixture of pulp and hydrogel particles on the central part of the absorbent body having this configuration. In addition, an air-through nonwoven fabric or a spunbonded nonwoven fabric made of synthetic fibers in which the fiber surface is hydrophilized with a surfactant can be used as an intermediate sheet between the topsheet 10 and the absorbent body 12.

  As a constituent fiber of the surface sheet 10 (nonwoven fabric), fibers conventionally used in the technical field such as natural fibers, semi-natural fibers, and synthetic fibers can be used without particular limitation. 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. In particular, it is preferable that the surface sheet 10 includes fibers that are three-dimensionally crimped in a coil shape by application of heat. Such a fiber can be included in the topsheet 10 by using latent crimped fibers as a raw material. The latent crimped fiber is composed of, for example, an eccentric core-sheath type composite fiber or a side-by-side type composite fiber containing two types of thermoplastic resins having different shrinkage rates as components. Examples thereof include those described in JP-A-9-296325 and Japanese Patent No. 2759331.

  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 top sheet 10 is preferably made hydrophilic. Examples of the hydrophilization method include a method of treating a hydrophobic non-woven fabric with a hydrophilizing agent. Moreover, the method of manufacturing a nonwoven fabric from the fiber which knead | mixed the hydrophilizing agent is mentioned. Further, there is a method of using a fiber having hydrophilicity inherently, for example, a natural or semi-natural fiber. Hydrophilicity can also be achieved by applying a surfactant after the production of the nonwoven fabric.

  The napkin 1 of this 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 napkin 1 according to the present embodiment employs the rigidity (density) distribution of the absorbent body 12 and the pair of linear grooves 60, 60 described above, so that the wearer's thighs can be worn from the left and right inward in the width direction when worn. When receiving a compressive force, the flexible low-rigidity region 12A (the central portion in the width direction of the excretory part facing part A) sandwiched between the pair of linear grooves 60, 60 rises toward the wearer's skin side. And since this protruding part adheres softly to the excretion part of the body, an excellent wearing feeling can be obtained. Further, a grooving structure composed of the ridge 20 and the groove 30 is formed on the skin contact surface side of the top sheet 11, and the grooving structure is excellent in cushioning and touch, so that the wearing feeling is further improved. Improvements are being made. Further, since the ridge groove structure is present on the skin contact surface side of the ridge, the ridge structure (the top of the ridge 20) and the skin rub against each other by moving the ridge from side to side during wearing. A wiping effect appears. By expressing this wiping effect, menstrual blood remaining on the skin can be scraped off and absorbed.

  Moreover, when the opening 31 is formed in the groove part 30 like this embodiment, when the said protruding part is formed by the deformation | transformation of the napkin 1, the opening 31 which exists in this protruding part becomes easy to open. Even when a pressure such as a seating pressure is applied to the napkin 1, a liquid conduction path through the opening 31 is stably secured, and a decrease in the absorption rate of body fluid is effectively prevented.

  Next, the suitable manufacturing method of the napkin 1 of this embodiment is demonstrated. First, the manufacturing method of the surface sheet 10 shown in FIG. 5 is demonstrated. The topsheet 10 is manufactured by the fluid entanglement method using the apparatus shown in FIG. In the manufacturing method using this apparatus, (a) a fiber assembly is supplied, and the fiber assembly is formed on a fluid-permeable support for forming a wavy structure in a direction orthogonal to the supply direction of the fiber assembly. (B) a step of spraying a fluid to the fiber assembly located on the support to separate the constituent fibers so as to form a slotted groove structure and an opening; and (c) subsequently on the support. There is a step of spraying a fluid again on the fiber assembly positioned to make the fiber assembly in which the groove structure and the opening are formed into a nonwoven fabric.

  The apparatus 40 shown in FIG. 8 includes a fluid permeable support 50, a first injection nozzle 51, and a second injection nozzle 52. As shown in FIG. 9, the fluid-permeable support 50 is a roll, and its peripheral surface is made of a fluid-permeable material such as a mesh. On the peripheral surface of the support 50, convex portions and concave portions extending along the rotation direction of the roll are alternately formed in the axial direction of the roll. Thereby, a wave-like structure can be formed in the fiber assembly 53 which is a raw material of the topsheet 10 in a direction orthogonal to the supply direction. Projections 54 formed intermittently along the rotation direction of the roll are located on the tops of the protrusions. The protrusions 54 are arranged at regular intervals along the rotation direction of the roll. And when it sees along the axial direction of a roll, the projection part 54 is arrange | positioned so that it may be located on a straight line.

  The 1st injection nozzle 51 and the 2nd injection nozzle 52 are arrange | positioned so that the surrounding surface of the support body 50 may be opposed. Each of the nozzles 51 and 52 has a structure capable of ejecting fluid over the entire width of the support 50. In the nozzles 51 and 52, the first injection nozzle 51 is located on the upstream side and the second injection nozzle 52 is located on the downstream side in the supply direction of the fiber assembly 53 that is the raw material of the topsheet 10.

  In the step (a), the fiber assembly 53 is supplied to the fluid permeable support 50 rotating in the direction of the arrow in FIG. 8 and conveyed while being held by the peripheral surface of the support 50. Is done. Next, in the step (b), the fluid ejected from the first ejection nozzle 51 is sprayed onto the fiber assembly 53 on the peripheral surface of the support 50. Due to the pressure of this fluid spraying, the fiber assembly 53 is displaced from the constituent fibers at the position of the convex portion 55 formed on the peripheral surface of the support 50 as shown in FIGS. 10 (a) and 10 (b). Dividing occurs. By this separation, the constituent fibers move into the concave portions 56 located between the convex portions 55. That is, fiber distribution occurs.

  Further, in the case where the protrusion 54 is formed on the top of the convex portion 55, as shown in FIG. 10C, the separation of the constituent fibers is further promoted, and the fiber assembly located on the protrusion 55 A hole is formed at 54. This hole becomes the opening 31 in the topsheet 10.

  As the fiber assembly, there can be used those in which fibers such as card web are not bonded or entangled, or the degree thereof is low, or those in which fibers such as nonwoven fabric are bonded or entangled. In particular, as a non-woven fabric, a non-woven fabric containing fibers having a fiber length of 30 mm or less and having no binder component itself, specifically, a dry type in which fibers between pulp fibers are fixed by a binder (adhesive component). It is preferable to use a pulp sheet.

  As the fluid used in this step, a liquid such as water and a gas such as air can be used. The type of fluid is selected according to the fiber assembly guided on the support 50. For example, when using a fiber assembly that is not bonded or entangled like a card web, it is preferable to use an air flow or a water vapor flow (steam jet). In the case of using a fiber assembly having bonds at fiber intersections, such as an air-through nonwoven fabric, it is preferable to use a water stream or a steam stream (steam jet). In the latter case, the grooving structure and the opening can be formed by the movement of the fiber while partly peeling the bond at the fiber intersection and keeping the degree of fiber entanglement low. In addition, it is possible to prevent clogging between the fibers. As described above, this step mainly forms the groove structure and the opening by the movement of the fiber, and the degree of the entanglement of the fiber is kept low.

  The above-mentioned water flow means a complete liquid flow such as water. A water vapor stream (steam jet) refers to a fluid stream of water that is not in a liquid state. When a liquid water flow or a water vapor flow (steam jet) is used, the fiber entanglement progresses as the fiber is located in the vicinity of the protrusion 55, and the fiber density of the portion tends to increase. In particular, when a nonwoven fabric is used as the fiber assembly (that is, re-nonwoven fabric), since the fiber 55 is hardly entangled with the convex portion 55, the cushion feeling inherent to the nonwoven fabric is maintained. On the other hand, the fibers located in the vicinity of the concave portion 56 and the protruding portion 55 are entangled, and the capillary gradient (density gradient) is relatively large with respect to the fibers located in the convex portion 55.

  When the groove structure and the opening are formed by spraying the fluid from the first injection nozzle 51 which is the step (b), then fiber entanglement is performed by spraying the fluid from the second injection nozzle 52 which is the step (c). And the fiber assembly is made into a nonwoven fabric (when a nonwoven fabric is used as the fiber assembly, it is made into a non-woven fabric). As the fluid used in this case, it is preferable to use a liquid water stream or a water vapor stream. By using these fluids, fiber entanglement can be performed efficiently. The above-mentioned re-non-woven fabric refers to the re-melting of the fiber from which the cut or fused portion of the fiber was peeled off in the previous step of forming the groove structure and the opening when the non-woven fabric was used as the fiber assembly. It means that the form as a nonwoven fabric is maintained by wearing or entanglement again.

  When the fluid sprayed to the fiber assembly 53 in the step (b) and the step (c) is concentrated on the convex portion 55 of the support body 50, the fluid pressure of the convex portion 55 is increased compared to the concave portion 56 of the support body 50. Therefore, it is preferable because the openability is improved. Moreover, it is preferable at the point which can make the fiber density of the edge part vicinity of a hole higher.

  When a steam flow is used as the fluid in the step (c), the steam flow from the second injection nozzle 52 is set to a relatively low temperature of 100 to 150 ° C. (a temperature lower than the fiber fusion temperature on the web). Thus, only fiber entanglement is performed. Since the water vapor stream has lower energy (injection pressure) than the liquid water stream (the dispersion of the fluid stream is large), it is preferable to use it when spraying the web rather than using a nonwoven fabric as the fiber assembly. This is because the movement of the fiber is easier in the web than in the non-woven fabric. However, even when a nonwoven fabric is used as the fiber assembly, the jet pressure that results in a weak fiber entangled state that does not recover the shape of the groove structure and the opening formed by the step (b) is caused by the steam flow. Can be given. Furthermore, in the case where the temperature of the water vapor flow is about 160 to 200 ° C., which is higher than the fiber fusion temperature on the web, even if the temperature is 20 ° C. or more higher than the fiber fusion temperature, the fibers in the fiber assembly The amount of heat applied is not so great that the resin constituting the fiber melts and flows strongly, and the flow of the resin does not always occur at the intersection of all fibers, so that the entire fiber assembly is not melted. It does not solidify. Therefore, even when the jet pressure of the water vapor flow is high and the fibers are in close proximity to each other, it is possible to perform fusion at the fiber intersection without causing fiber clogging.

  Since this fusion is performed by the water vapor flow blown from the second injection nozzle 52, a stronger pressure is applied to the fiber assembly in a short time compared to the air-through method, which is a known nonwoven fabric manufacturing technique. Therefore, the pressure is removed before the fusion at the fiber intersection is stabilized, that is, before the outflow of the fiber sheath component resin that spreads on the surface of each fiber and becomes a strong fusion point is fixed. As a result, the fibers are separated to form a bridge structure. Such a bridging structure is estimated to be formed by melting and solidifying the sheath component resin of one of the two fibers. This is because, although this fusion process is in a state of causing fiber fusion, the application of heat is completed in a relatively short time, so the resins constituting the fibers that cause fiber fusion fuse together to form a resin. This is because it is considered that there is an interface between the resins constituting each fiber that causes fiber fusion rather than a state in which the interface between them disappears. In addition, if elongation occurs near the interface between the resin, which is the fusion part that has caused fiber fusion, the interface is pulled, the fusion part is reduced, and the resins are separated at the interface. Because it is. For this reason, the bridging structure has a portion where the area of the joint portion is large but the resin is stretched and thinned. As a result, the obtained surface sheet 10 is improved in the degree of freedom of its constituent fibers, and the flexibility and cushioning properties are improved. On the other hand, since it is manufactured under a pressure stronger than that of the air-through method, it is easier to make a multi-intersection of more than two fibers. With such a structure, the strength of the topsheet 10 is improved.

  When a liquid water stream is used in step (b) and / or step (c), the surfactant used for imparting hydrophilicity may flow down from the fiber surface, so that the surface activity into the fiber may occur. It is preferable to use a kneaded agent or a natural / semi-natural hydrophilic fiber. Or it is preferable to apply | coat surfactant in a post process. On the other hand, when the water vapor flow is used, there is an advantage that the surfactant on the surface of the fiber is less likely to flow down and the surfactant can be easily collected at a part where the fiber density is high. As a result, when the water vapor flow is used, the fiber density of the portions located in the concave portions 56 and the projections 54 of the support 50 in the fiber assembly 53 is increased, so that the hydrophilicity of these portions can be inevitably increased. As an application example of this effect, there is a technique in which two or more kinds of surfactants to be applied to the fiber surface or surfactants kneaded into the fiber are used, and the water resistance of the surfactant is made different. This method is advantageous because the hydrophilic gradient can be designed more easily.

  In order to further control the fiber density of the obtained surface sheet 10, it is also preferable to subject the nonwoven fabric after the step (c) to a hot air treatment step. The hot air treatment has an effect of promoting the formation of a nonwoven fabric (bonding the fibers of the fiber assembly) and / or eliminating clogging between the fibers. In other words, in the step (c), from the viewpoint of preventing clogging, the fluid spraying condition may be weakened, and the hot air treatment step may be applied to compensate for the lack of fiber entanglement or fiber fusion resulting therefrom. preferable. Moreover, it is preferable to attach to the hot-air treatment process in order to recover the bulk of the nonwoven fabric in which clogging has occurred in the process (c) or to develop fiber deformation (crimping or stretching). In particular, when the steam flow is used in the step (c), the second spray nozzle 52 is used, so that the heat application step is completed in a shorter time than the air-through method. Therefore, from the viewpoint of stabilizing the heat-sealed state, it is desirable to perform a hot air treatment process at about 80 to 120 ° C. as a subsequent process of the process (c). Or it is preferable to perform the stabilization process which does not raise | generate a rapid temperature fall as a post process of the process of (c). The hot air treatment may be performed in one stage, or the hot air treatment for promoting the formation of a nonwoven fabric and the hot air treatment for restoring the bulk of the nonwoven fabric may be performed in a plurality of stages.

  When only the web is used as the fiber assembly in this production method, it is preferable to use an air flow or a water vapor flow in the step (b) and use a water vapor flow in the step (c). This is because clogging between fibers can be prevented, a flexible structure can be formed by forming a nonwoven fabric by fusing the fiber intersections, and the fiber density at the periphery of the apertures 31 can be easily increased. Further, when an air flow is used in the step (b), it becomes easy to form a liquid introduction pipe in the opening 31, and parts other than the opening 31 are also likely to have the shape of FIG. Improves. On the other hand, when the water vapor flow is used in the step (b), the scattering of the fibers is suppressed and the fluid pressure can be easily made higher than the air flow. It becomes easy to improve flexibility such as cushioning. Even if the water vapor flow is used in the step (b), it is possible to achieve both the liquid guide tube structure and the cross-sectional shape of FIG. 6 by adjusting the fluid pressure in the opening 31.

  In this production method, when a water stream is used in the steps (b) and (c), it is preferable to use a nonwoven fabric having a fusion point at the fiber intersection. The reason for this is that fiber clogging can be prevented by the movement of fibers (formation of a density-enhanced portion) by the separation portion at the fiber intersection and the remaining fusion point. In this case, in the step (b), the nonwoven fabric is adapted to the shape of the support by applying a water flow so as to be substantially uniform over the entire nonwoven fabric, and in the step (c), the grooves 30 including the openings 31 are It is preferable from the viewpoint of facilitating re-entanglement by facilitating peeling of the fusion point and making the water pressure in the step (c) higher than (b) by facilitating entanglement by blowing a stronger water flow than the part 20. Further, when a method of supplying a fiber assembly 53 by using a laminate of a web and a nonwoven fabric as a fiber assembly 53 or by laminating both webs and a nonwoven fabric while supplying the fiber assembly 53, (B) and ( Integration of the two can be promoted in step c). The nonwoven fabric produced in this way has a structure (integrated structure) that can easily guide the liquid from the top portion 21 of the collar portion 20 to the end portion of the opening 31. In this case, it is preferable to use a nonwoven fabric from the viewpoint of preventing fiber clogging in the web and the nonwoven fabric from which water is directly sprayed. Thus, when a water flow is used in the steps (b) and (c), it becomes easy to obtain a cross-sectional shape as shown in FIG.

  When a non-woven fabric is used as the fiber assembly 53 and the non-woven fabric is separately guided onto the support before the step (b), the flexibility and cushioning properties of the resulting non-woven fabric can be improved. In addition, when using a nonwoven fabric as the fiber assembly 53, if the fibers are strongly bonded or entangled in the nonwoven fabric, fiber movement in the step (b) may be difficult to occur, so before the step (b), It is also preferable to subject the non-woven fabric to a portion to be positioned in the concave portion 56 of the support 50.

  The sheet thus obtained is placed on the separately manufactured absorber 12, and a linear groove 60 is formed in which both are joined and integrated using a pressing device such as an embossing device. In forming these grooves, heat may or may not be applied. After the top sheet 10 and the absorbent body 12 are thus processed, the top sheet and the like are then processed together with the back sheet 11 according to a conventional method to obtain the target napkin 1.

  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 absorbent body 12 in the above-described embodiment has the low rigidity region 12A in the entire width direction center portion, but only a part of the width direction center portion of the absorber 12 is low as shown in FIG. It may be a rigid region 12A. Thus, when only a part of the widthwise central portion of the absorbent body 12 is the low-rigidity region 12A, the low-rigidity region 12A is disposed at least in the excretion portion facing portion A that faces the excretion portion of the wearer, This is preferable in that the raised portion and the excretory portion are in close contact with each other.

  Moreover, as the surface sheet 10, as described above, a sheet having a cross-sectional shape as shown in FIG. 6, FIG. 7 (a), or (b) can be used freely, but the form shown in FIG. 30 and the absorber 12 located therebelow, a space is easily formed, and this space is particularly excellent for the purpose of quick liquid passage. This is especially effective for large quantities. On the other hand, the configurations shown in FIGS. 7A and 7B are particularly effective for the purpose of drawing the liquid because the groove 30 is easy to contact the absorber 12.

  Further, in addition to the pair of linear grooves 60 described above, a second groove for the purpose of improving leakage prevention may be formed on the skin contact surface side of the napkin 1. FIG. 12 shows a main part (absorber 12) of the embodiment having the second groove. In FIG. 12, for ease of explanation, only the absorber 12 and the grooves 60 and 70 are shown, and the description of other napkin constituent members is omitted, but the other napkin constituent members are the same as in the above embodiment. Can be configured.

  In the embodiment shown in FIG. 12, the second groove 70 has substantially the same shape as the linear groove 60 and extends in the longitudinal direction of the napkin 1. The second groove 70 is connected to the rear end portion 60 </ b> C of the linear groove 60 and extends to a part of the rear portion C, and is a continuous groove formed by the linear groove 60 and the second groove 70. Is forming. Similar to the linear groove 60, the second groove 70 can be formed by integrating the topsheet 10 and the absorber 12 by pressure bonding.

  Further, a leak-proof cover sheet may be disposed on the top sheet 10 in the left and right side areas of the napkin 1. Further, a pair of wings extending outward in the width direction may be provided on both side edges in the longitudinal direction of the napkin 1. Moreover, in the said embodiment, although the sanitary napkin was mentioned as one of the application examples of the absorbent article of this invention, it is applicable also to absorbent articles, such as a panty liner (orimono sheet), for example. Each structure mentioned above can be combined suitably.

FIG. 1 is a plan view showing a skin contact surface side (surface sheet side) of a sanitary napkin according to an 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 schematic diagram of a cross section taken along the line I-I showing a state in which the napkin shown in FIG. 1 receives a compressive force from the width direction when worn. FIG. 4A is a plan view showing an example of a linear groove applicable to the present invention, and FIGS. 4B and 4C are explanatory views of the function and effect of the linear groove according to the present invention. FIG. FIG. 5 is a perspective view schematically showing an enlarged main part of the top sheet used for the napkin shown in FIG. 1. FIG. 6 is a schematic diagram of a cross section taken along line II-II in FIG. FIG. 7 is a view corresponding to FIG. 6 showing a state of another cross section of the top sheet used for the napkin shown in FIG. 1. 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 fluid-permeable support in FIG. FIG. 10 is a schematic diagram showing a process of manufacturing a top sheet using the apparatus shown in FIG. FIG. 11 is a plan view of another absorber used in the napkin shown in FIG. FIG. 12 is a plan view showing another absorbent body used in the napkin shown in FIG. 1 together with a groove.

Explanation of symbols

1 Sanitary napkin (absorbent article)
DESCRIPTION OF SYMBOLS 10 Top sheet 11 Back sheet 12 Absorber 12A Absorber low-rigidity area 12B Absorber high-rigid area 20 Gutter part 30 Groove part 31 Opening 60 Linear groove 60A Linear groove center part 60B Linear groove front end part 60C Rear end A of the linear groove Excretion part facing part B Front part C Rear part

Claims (5)

In a vertically long absorbent article provided with a surface sheet on the skin contact surface side, a back sheet on the non-skin contact surface side, and an absorber between the both sheets,
The surface sheet is made of a nonwoven fabric having alternately ridges and grooves extending in the longitudinal direction of the absorbent article, and the amount of fibers in the ridges is substantially larger than that of the grooves,
On the skin contact surface side of the surface sheet, a pair of linear grooves formed by integrating the surface sheet and the absorbent body by pressure bonding are formed,
Each of the pair of linear grooves has a central portion extending in the longitudinal direction of the absorbent article, and a front end portion and a rear end portion extending inward of the absorbent article from the longitudinal front and rear ends of the central portion. And
The absorbent body has a low-rigidity region located in the central portion in the width direction of the absorbent article and a high-rigidity region having higher rigidity than the low-rigidity region,
The pair of linear grooves are formed in the low rigidity region,
Absorbency where the low-rigidity region exists between a pair of the linear grooves, and the high-rigidity region exists outside the center of the pair of the linear grooves in the width direction of the absorbent article. Goods.   The absorptive article according to claim 1 in which said back sheet and said absorber are not joined between a pair of said linear grooves.   The absorbent article according to claim 1, wherein the top sheet and the absorbent body are bonded via an adhesive between the pair of linear grooves.   The absorbent article in any one of Claims 1-3 in which the opening is formed in the said groove part.   The absorber is formed by uniformly embossing a part of the precursor of the absorber having substantially uniform rigidity, and the embossed portion is the high-rigidity region, The absorbent article according to any one of claims 1 to 4, wherein a portion not subjected to embossing treatment is the low-rigidity region.

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