JP5604393B2 - Absorbent articles - Google Patents

Description

  The present invention relates to absorbent articles such as sanitary napkins, disposable diapers, and incontinence pads.

  2. Description of the Related Art Absorbent articles such as sanitary napkins are known that have an absorbent body including a top sheet, a back sheet, and a liquid-retaining absorbent core interposed between both sheets, and are substantially vertically long. The present applicant has previously proposed an absorbent article provided with a back sheet made of a moisture permeable sheet having a predetermined moisture permeability, in order to effectively reduce the humidity in the wearing during use of the absorbent article. (See Patent Document 1). According to the absorbent article described in Patent Document 1, the humidity in the dress is effectively reduced, there is less discomfort such as swelling and stickiness, and there is a comfortable texture, and skin troubles such as kayumi and burring are caused. Difficult to develop.

  In addition, the present application includes an absorbent body in which a large number of compressed portions that are depressed from the top sheet side are separated from each other, separately from the absorbent article including the back sheet having a predetermined moisture permeability. An absorbent article was proposed (see Patent Document 2). According to the absorbent article described in Patent Document 2, it is excellent in liquid return at the time of use, and can provide a comfortable wearing feeling with a reduced wet feeling without leaving liquid on the surface.

JP-A-7-132126 Japanese Patent No. 4173844

  As described above, according to the absorbent article described in Patent Document 1, it is possible to effectively reduce the humidity in the wearing, but in recent years, the humidity in the wearing has been further effectively reduced. There has been an increasing demand for absorbent articles that further reduce the wet feeling and provide a more comfortable wearing feeling.

  Therefore, the subject of this invention is providing the absorbent article which can satisfy the demand mentioned above.

  The present invention is a vertically long absorbent article comprising a top sheet disposed on the skin facing surface side, a back sheet disposed on the non-skin facing surface side, and a vertically long absorbent body interposed between both sheets. The back sheet has moisture permeability, and the absorber has a high basis weight part with a relatively high basis weight and a low basis weight with a relatively low basis weight adjacent to the high basis weight part. And the high basis weight part and the low basis weight part are integrally formed, and on the back sheet side of the absorbent body, the convex part and the low basis weight are the high basis weight part. The concave-convex structure is formed by alternately arranging the concave portions, and the low basis weight portion is unevenly distributed on the surface sheet side of the absorber, and the concave portion is recessed on the surface sheet side. And the convex part is convex on the back sheet side, and the space formed by the concave part and the back sheet is continuously at least in the longitudinal direction. There is provided a Biteiru absorbent article.

  According to the absorbent article of the present invention, it is possible to effectively reduce the humidity in the wearing during use, further reduce the wet feeling, and give a more comfortable wearing feeling.

FIG. 1 is a partially cutaway perspective view showing an embodiment of the absorbent article of the present invention from the skin facing surface side. 2 is a cross-sectional view schematically showing a cross section taken along line Y1-Y1 of FIG. FIG. 3 is a plan view showing the absorbent core used in the absorbent article shown in FIG. 1 from the skin facing surface side. 4A is a cross-sectional view schematically showing a cross section taken along line Y2-Y2 of FIG. 3, and FIG. 4B is a cross-sectional view schematically showing a cross section taken along line Y3-Y3 of FIG. FIG. 5 is a schematic cross-sectional view of an embodiment of a method for manufacturing the absorbent body (absorbent core) shown in FIG. 3 and a manufacturing apparatus used therefor. 6 is a schematic cross-sectional view along the width direction of a part (concave portion) on the outer peripheral surface side of the rotating drum shown in FIG. FIG. 7 is a schematic cross-sectional view showing a state where an absorbent material is deposited in the concave portion of the rotating drum shown in FIG. FIG. 8 is an explanatory diagram of the compression process of the deposit.

Hereinafter, the absorbent article of this invention is demonstrated based on the preferable embodiment, referring FIGS. 1-8. Examples of the absorbent article 1 of the present embodiment (hereinafter also referred to as “absorbent article 1”) include sanitary napkins, disposable diapers, and incontinence pads.
The absorbent article 1 has a liquid-permeable surface sheet 2 disposed on the skin facing surface (surface facing the wearer's skin side) and a non-skin facing surface (opposite to the wearer's skin side). A longitudinally absorbent main body 10 having a liquid-impermeable rear surface sheet 3 disposed on the side and a longitudinally absorbent body 4 interposed between the sheets 2 and 3. As shown in FIG. 1, the absorbent article 1 is formed symmetrically with respect to a center line CL extending in the longitudinal direction of the absorbent main body 10. The “X” direction shown in each figure is a direction parallel to the center line CL, and is also the same direction as the longitudinal direction of the absorbent main body 10. Moreover, the “Y” direction shown in each figure is a direction orthogonal to the center line CL, and is also the same direction as the width direction of the absorbent main body 10.

As shown in FIG. 1, each of the topsheet 2 and the backsheet 3 forming the absorbent main body 10 has an elongated shape that is long in the longitudinal direction (X direction) of the absorbent main body 10. It has a contour that matches the contour of the main body 10. Thus, as for the surface sheet 2 and the back surface sheet 3, in the absorbent article 1, the surface sheet 2 and the back surface sheet 3 are formed in the same shape and size. As shown in FIGS. 1 and 2, each of the top sheet 2 and the back sheet 3 covers the entire surface on the skin facing surface side and the entire surface on the non-skin facing surface side of the absorber 4, and extends from the periphery of the absorber 4. It has the extended part which protrudes, These extended parts are joined by hot embossing, and the peripheral seal part 5 is formed in the peripheral part.
In the absorbent article 1, the peripheral seal portion 5 is formed by hot embossing, but may be formed by ultrasonic sealing, or may be formed by an adhesive such as hot melt.

  The absorbent body 4 includes an absorbent core 40 including an absorbent material 45 (a fiber material such as pulp, a water-absorbing polymer, etc.). The absorbent body 4 in the present embodiment is configured by covering the absorbent core 40 with a core wrap sheet (not shown) made of tissue paper or a water-permeable nonwoven fabric. The absorptive core 40 may be comprised only from fiber materials, such as a pulp, and may hold | maintain a water absorbing polymer between this fiber material. Between the top sheet 2 and the absorbent body 4 and between the absorbent body 4 and the back sheet 3 are bonded to each other by a pattern-coated adhesive (hot melt adhesive or the like) such as dots, spirals and stripes. Also good.

  In the present invention, the absorbent body 4 has a high basis weight portion 41 having a relatively high basis weight and a low basis weight portion 42 having a relatively low basis weight adjacent to the high basis weight portion 41. Yes. Specifically, in the absorbent article 1, as shown in FIGS. 2 and 3, the absorbent core 40 constituting the absorbent body 4 includes a high basis weight portion 41 and an absorbent material that are relatively rich in absorbent material. Has a relatively low low basis weight portion 42 (42X, 42Y). 2 and 3, the absorbent core 40 has a linear (continuous linear) low basis weight portion 42X extending along the longitudinal direction X and a linear (continuous) extending along the width direction Y. A plurality of straight basis) low basis weight portions 42Y are formed. As shown in FIGS. 2 and 3, the low basis weight portion 42 includes a linear low basis weight portion 42 </ b> X extending in the longitudinal direction X and a linear low basis weight portion 42 </ b> Y extending in the width direction Y as a whole. It is formed in a lattice shape, and a high basis weight portion 41 is arranged at a portion (the position of the lattice eye) partitioned by these linear low basis weight portions 42X and 42Y. Each of the plurality of linear low basis weight portions 42X is formed to extend over the entire length in the longitudinal direction X of the absorbent core 40, and each of the plurality of linear low basis weight portions 42Y is absorbent. The core 40 is formed to extend over the entire length in the width direction Y.

  In this invention, as shown in FIG. 2, the high basic weight part 41 and the low basic weight part 42 are integrally molded, and the convex part which is the high basic weight part 41 and the back surface sheet 3 side of the absorber 4 and The concave-convex structure in which the concave portions that are the low basis weight portions 42 are alternately arranged is formed, and the low basis weight portions 42 are unevenly distributed on the surface sheet 2 side of the absorbent body 4. Here, “being integrally formed” means that the high basis weight portion 41 and the low basis weight portion 42 are integrated so as not to be separated from each other without using a bonding means such as an adhesive or heat fusion, It means that it is integrally formed from the same material. Thus, if the high basic weight part 41 and the low basic weight part 42 are integrally molded, it will have the continuity which a bodily fluid can move smoothly. As shown in FIG. 2, the low basis weight portion 42 is unevenly distributed on the topsheet 2 side (the skin facing surface side of the absorbent body 4) in the thickness direction T of the absorbent article 1. And since the low basic weight part 42 is unevenly distributed in the surface sheet 2 side of the thickness direction T in this way, as shown in FIG. 2, the high basic weight part 41 is the opposite side to the surface sheet 2 side, That is, it protrudes to the back sheet 3 side in the thickness direction T (the non-skin facing surface side of the absorber 4). In the absorbent core 40, the skin facing surface (surface on the topsheet 2 side) side of the absorbent core 40 is composed of the low basis weight portion 42 and is substantially formed in a substantially flat shape. Further, in the absorbent core 40, a plurality of high basis weight portions 41 (convex portions) and high basis weight portions 41 that are formed to protrude on the non-skin facing surface (surface on the back sheet 3 side) side of the absorbent core 40. , 41 and a low basis weight portion 42 (concave portion) is formed between the concave and convex portions.

  In the absorbent article 1 formed as described above, as shown in FIG. 2, the low basis weight portion (concave portion) 42 is recessed toward the topsheet 2, and the high basis weight portion (convex portion) 41 is the back surface. Convex on the sheet 3 side. That is, the concave portion recessed on the surface sheet 2 side in the concavo-convex structure of the absorber 4 is mainly formed by the low basis weight portion 42, and the convex portion protruding toward the back sheet 3 side in the concavo-convex structure of the absorber 4 is mainly The high basis weight portion 41 is formed. Here, “the recess is mainly formed by the low basis weight portion 42” means that the high basis weight portion 41 near the boundary between the low basis weight portion 42 and the high basis weight portion 41 forms a part of the recess. Similarly, “the convex portion is mainly formed by the high basis weight portion 41” means that the low basis weight in the vicinity of the boundary between the high basis weight portion 41 and the low basis weight portion 42. This means that the amount portion 42 forms a part of the convex portion.

In the case where the absorbent article 1 is used for a sanitary napkin, the width L1 of the low basis weight portion 42 is easy to bend according to the shape of the wearer's body, and the smoothness of the surface is taken into consideration for the wearer. From the viewpoint of providing an excellent wearing feeling, it is preferably 0.5 to 2.5 mm, and more preferably 0.5 to 1.5 mm.
Moreover, when the absorbent article 1 is used for a disposable diaper, the width L1 of the low basis weight portion 42 takes into account that the low density portion temporarily acquires the liquid and quickly draws the liquid from the surface. From the viewpoint that it is necessary to design slightly larger than the design value of the sanitary napkin, it is preferably 1.0 to 7.0 mm, and more preferably 1.0 to 5.0 mm.
Note that the width L1 may be the same or different between the low basis weight portion 42X in the longitudinal direction X and 42Y in the width direction Y. The width L1 is a measured value at the position of the bottom of the recess in the concavo-convex structure of the absorber 4.

In the case where the absorbent article 1 is used for a sanitary napkin, the low basis weight portion 42 (42X, 42Y) forming the recess has a basis weight of 20 to 200 g / m ² and 50 to 150 g / m ^2. It is preferable that Moreover, as for the high basic weight part 41 which forms a convex part, the basic weight is 50-500 g / m < ² >, and it is preferable that it is 100-400 g / m < ² >. Moreover, the thickness of the low basic weight part 42 (concave part) is 80% or less of the thickness of the high basic weight part 41 (convex part), Preferably it is 70% or less, and the thickness of the low basic weight part 42 (concave part) is 0. It is preferable that it is 3-3.0 mm, and it is preferable that it is 0.5-2.0 mm. Furthermore, the thickness of the high basis weight portion 41 (convex portion) is preferably 0.5 to 7.0 mm, and more preferably 1.0 to 5.0 mm.
In the case where the absorbent article 1 is used in a disposable diaper, the low basis weight portions 42 (42X, 42Y) that form the recesses temporarily acquire the liquid and take the function of quickly extracting the liquid from the surface. From the viewpoint that the basis weight is preferably designed to be slightly larger than the design value of the sanitary napkin, the basis weight is 30 to 300 g / m ² and preferably 50 to 200 g / m ^2. . Moreover, as for the high basic weight part 41 which forms a convex part, the basic weight is 100-700 g / m < ² >, and it is preferable that it is 150-500 g / m < ² >. Moreover, the thickness of the low basic weight part 42 (concave part) is 80% or less of the thickness of the high basic weight part 41 (convex part), Preferably it is 70% or less, and the thickness of the low basic weight part 42 (concave part) is 0. It is preferable that it is 3-5.0 mm, and it is preferable that it is 0.5-3.0 mm. Furthermore, it is preferable that the thickness of the high basic weight part 41 (convex part) is 1.0-9.0 mm, and it is preferable that it is 1.5-7.0 mm.
In addition, the thickness of the high basic weight part 41 (convex part) and the low basic weight part 42 (42X, 42Y) (recessed part) is the width direction (a) shown in FIG. Y direction) or in the longitudinal direction X, and the cross section of the cut sample is measured. The thickness of the high basis weight part 41 (convex part) is a value measured at the thickest position in the convex part, and the thickness of the low basis weight part 42 (concave part) is a value measured at the thinnest position in the concave part. is there. When it is difficult to measure with the naked eye, the section of the cut sample may be observed and measured at a magnification of 25 to 50 times using, for example, a microscope (VHX-1000 manufactured by KEYENCE).
The basic weight of the high basic weight part 41 and the low basic weight part 42 is measured as follows.

<Measurement method of basis weight>
The measuring method of the basic weight of the high basic weight part 41 and the low basic weight part 42 is as follows.
The absorbent body 4 is cut at the boundary line portion between the high basis weight portion 41 and the low basis weight portion 42 using a single blade razor manufactured by Feather Corporation. Ten pieces of the high basis weight portion 41 obtained by cutting were measured using an electronic balance (Electronic balance GR-300 manufactured by A & D, accuracy: 4 digits after the decimal point), and averaged to obtain a high basis weight portion 41. Find the weight of one small piece. The basis weight of the high basis weight portion 41 is calculated by dividing the calculated weight by the area per piece of the high basis weight portion 41 calculated from the design dimensions of the high basis weight portion 41.
Next, along the boundary line extending in the product longitudinal direction of the high basis weight portion 41 and the low basis weight portion 42, the length is 100 mm, and the width is a piece manufactured by Feather Co., Ltd. according to the design dimensions of the width of the low basis weight portion 42. Using a blade razor, cut out five samples of the thin striped low basis weight portion 42. The obtained five samples are each measured using an electronic balance (Electronic balance GR-300 manufactured by A & D, accuracy: 4 digits after the decimal point), and the weight of one sample of the low basis weight portion 42 is obtained on average. The calculated weight is divided by the area of the sample of the low basis weight portion 42 to calculate the basis weight of the low basis weight portion 41.

In the absorbent body 4 of the absorbent article 1, the high basis weight portion 41 has more absorbent material than the low basis weight portion 42, and thus the high basis weight portion 41 includes the low basis weight portion 42 ( 42X, 42Y).
When the absorbent article 1 is used for a sanitary napkin, the ratio (D41 / D42) between the density D41 of the high basis weight portion 41 and the density D42 of the low basis weight portion 42 is 1/4 to 3/4. It is preferable that it is 1/3 to 2/3. Further, the low basis amount unit 42 for forming the recess, its density of 0.03~0.18g / cm ^3, it is preferable that 0.05~0.15g / cm ^3. Also, high basis weight portion 41 to form the protrusions, the density of 0.05~0.50g / cm ^3, is preferably 0.10 to 0.40 g / cm ^3.
When the absorbent article 1 is used for a disposable diaper, the ratio (D41 / D42) of the density D41 of the high basis weight portion 41 and the density D42 of the low basis weight portion 42 is 1/5 to 3/4. It is preferable that it is 1/4 to 2/3. Moreover, the density of the low basis weight part 42 which forms a recessed part is 0.01-0.20 g / cm < ³ >, and it is preferable that it is 0.03-0.15 g / cm < ³ >. Also, high basis weight portion 41 to form the protrusions, the density of 0.05~0.50g / cm ^3, is preferably 0.10 to 0.40 g / cm ^3.
The density of the high basic weight part 41 and the low basic weight part 42 is measured as follows.

<Density measurement method>
A cross section corresponding to FIG. 2 of the absorbent body 4 is observed using a microscope VHX-1000 manufactured by KEYENCE, and the thicknesses of the high basis weight portion 41 and the low basis weight portion 42 are measured.
Dividing the basis weights of the high basis weight portion 41 and the low density portion 42 obtained by the method described in the paragraph [0018] above by the measured thicknesses, the densities of the high basis weight portion 41 and the low basis weight portion 42 are obtained. calculate.

  As shown in FIG. 3, the high basis weight portion 41 that forms the convex portion is formed in a circular arc shape in a plan view as shown in FIG. 3. Specifically, as shown in FIG. 3, the high basis weight portion 41 of the absorbent article 1 has a four-corner arc shape in plan view, and the radius of curvature of each corner is 0.5 to 5.0 mm. It is preferable that it is 1.0-3.0 mm. Thus, when the corner of the high basis weight portion 41 is formed in an arc shape, the high basis weight portion 41 stacked in the drum recess 51 formed on the rotary drum 50 is transferred onto the mesh belt 75. In this case, it is easy to be quickly transferred from the drum recess 51, and the effect of improving the moldability of the high basis weight portion 41 is achieved. In the absorbent article 1, the corners are formed in an arc shape when the high basis weight portion 41 is viewed in a plan view, but the shape may not be an arc shape, and the plan view shape of the high basis weight portion 41 is A rectangular shape, an ellipse, etc. may be sufficient.

As shown in FIG. 3, the high basis weight portion 41 that forms the convex portion has a length L2 in the longitudinal direction X of 10 when the absorbent article 1 is used for a sanitary napkin in plan view. It is preferably ˜30 mm, and more preferably 15 to 25 mm. Moreover, it is preferable that the length L3 of the width direction Y is 5-25 mm, and it is still more preferable that it is 7.5-20 mm.
When the absorbent article 1 is used for a disposable diaper, the length L2 in the longitudinal direction X of the high basis weight portion 41 forming the convex portion is preferably 10 to 70 mm, and is 20 to 60 mm. More preferably. Moreover, it is preferable that the length L3 of the width direction Y is 5-50 mm, and it is still more preferable that it is 10-40 mm.

  In the present invention, as shown in FIG. 2 and FIG. 3, the space 6 formed by the concave portion (low basis weight portion) 42 and the back sheet 3 in the concave-convex structure of the absorbent body 4 on the side of the top sheet 2, It extends continuously in at least the longitudinal direction X. As described above, in the absorbent article 1, as shown in FIGS. 2 and 3, the low basis weight portions 42 (42 </ b> X and 42 </ b> Y) are formed in a lattice shape as a whole, and a high basis weight is provided at the position of the lattice. The portion 41 is disposed, and the concave portion (low basis weight portion 42) is disposed so as to surround the convex portion (high basis weight portion 41). Thus, in the absorbent article 1, as shown in FIGS. 2 and 3, a plurality of continuous linear recesses (low basis weight portions 42 </ b> X) extending in the longitudinal direction X and a plurality of back sheets 3 are formed. The space 6X extends continuously in the longitudinal direction X, and the plurality of spaces 6Y formed by the continuous linear recesses (low basis weight portion 42Y) extending in the width direction Y and the back sheet 3 have a width. Each extends continuously in the direction Y.

In the sanitary napkin, the humidity in the dressing is particularly high due to absorption of menstrual blood, and in the disposable diaper, the humidity in the dressing is considered to be particularly high due to absorption of urine.
In the sanitary napkin, from the viewpoint of effectively reducing the humidity in the wearing during use, when the absorbent article 1 is used for a sanitary napkin, the space 6X (low) continuously extending in the longitudinal direction X is used. 2 or more are preferable, and it is more preferable that 3 or more are provided.
In disposable diapers, the amount of urine absorbed per disposable diaper is generally larger than the amount of menstrual blood absorbed per sanitary napkin. Generally, disposable diapers are more disposable than sanitary napkins. A space extending continuously in the longitudinal direction X in the case where the absorbent article 1 is used in a disposable diaper from the viewpoint of further effectively reducing the humidity in the wearing during use because the absorbent body is wide. 6X (the same number as the low basis weight portion 42X) is preferably arranged in three or more, and more preferably four or more.
For the same reason, when the absorbent article 1 is used for a sanitary napkin, eight or more spaces 6Y (the same number as the low basis weight portion 42Y) continuously extending in the width direction Y are arranged. It is preferable that 10 or more are arranged. When the absorbent article 1 is used in a disposable diaper, it is preferable that 10 or more spaces 6Y (the same number as the low basis weight portion 42Y) extending continuously in the width direction Y are arranged, 12 More preferably, it is arranged above.

  In the absorbent article 1, the absorbent body 4 corresponds to the concave portion (low basis weight portion 42) of the concavo-convex structure on the back sheet 3 side on the top sheet 2 side of the absorbent body 4, as shown in FIG. And it has the surface side recessed part 43 dented in the back surface sheet 3 side. Specifically, as described above, in the absorbent article 1, the recess (low basis weight portion 42) has a plurality of continuous linear recesses (low basis weight portions) extending in the longitudinal direction X as shown in FIG. 3. 42X) and a plurality of continuous linear recesses (low basis weight portion 42Y) extending in the width direction Y. Therefore, in the absorbent article 1, the absorbent body 4 corresponds to the plurality of continuous linear recesses (low basis weight portions 42 </ b> X) extending in the longitudinal direction X, and the surface of the topsheet 2 side on the backsheet 3 side. A plurality of surface side recesses 43X (see FIGS. 3 and 4A). Each surface side recess 43X extends in a straight line shape in the longitudinal direction X and extends in the width direction Y. Corresponding to each of the plurality of continuous linear recesses (low basis weight portion 42Y), the surface sheet 2 side has a plurality of surface side recesses 43Y (see FIG. 3) recessed on the back sheet 3 side, The front surface side recess 43Y extends in a continuous straight line in the width direction Y. As shown in FIG. 3, the number of the low basis weight portions 42X (space 6X) is the same as the number of the surface side recesses 43X, the number of the low basis weight portions 42Y (space 6Y), and the number of the surface side recesses 43Y. Are the same number.

  As described above, the absorbent body 4 of the absorbent article 1 has the surface side concave portions 43X and 43Y corresponding to the concave portions (low basis weight portions 42X and 42Y) of the concave-convex structure as shown in FIG. However, the absorbent article 1 is easily deformed in a convex shape toward the wearer's skin to improve fit and prevent leakage, and the non-skin compared to the wearer's skin contact surface of the absorbent body 4 By increasing the area of the contact surface, the absorbed liquid is more easily evaporated from the non-skin contact surface, and from the viewpoint of preventing an increase in humidity on the skin contact surface side, The depth d2 of the quantity parts 42X, 42Y) is deeper than the depth d1 of the surface side recesses 43X, 43Y. The depth d2 of the recesses (low basis weight portions 42X, 42Y) is preferably at least 3 times the depth d1 of the surface side recesses 43X, 43Y, and more preferably at least 5 times the depth d1. The depth d1 of the surface side concave portions 43X and 43Y is preferably 2 to 20% of the thickness of the convex portion (high basis weight portion 41) in the absorbent body 4 (absorbent core 40), and is 3 to 15%. More preferably. The depth d2 of the recesses (low basis weight portions 42X, 42Y) and the depth d1 of the surface side recesses 43X, 43Y are the thicknesses of the high basis weight portion 41 (convex portion) and the low basis weight portion 42 (recessed portion) described above. Measure in the same manner as above.

As shown in FIG. 4A, the absorbent body 4 (absorbent core 40) of the absorbent article 1 is a length of the lower side L <b> 5 on the back sheet 3 side as viewed in cross section across the width direction (Y direction). However, it is longer than the length of the upper side L4 on the surface sheet 2 side.
In particular, when the absorbent article 1 is used for a sanitary napkin, the length of the lower side L5 is the length of the upper side L4 from the viewpoint of effectively reducing the humidity generated from menstrual blood absorbed by the absorbent body 4. The thickness is preferably 1.5 to 5 times, and more preferably 2 to 4 times.
In particular, when the absorbent article 1 is used in a disposable diaper, the length of the lower side L5 is the length of the upper side L4 from the viewpoint of effectively reducing the humidity generated from the urine absorbed by the absorbent body 4. The thickness is preferably 1.5 to 7 times, more preferably 2 to 5 times.
The length of the lower side L5 is measured in the same manner as the thicknesses of the high basis weight portion 41 (convex portion) and the low basis weight portion 42 (concave portion) described above. The lower side L5 is a contour path, and the lower side L5 is the length in the width direction (Y direction) at the top of the convex portion (high basis weight portion 41) of the concavo-convex structure on the back sheet 3 side, and the convex portion (high plow). Measure the length of the pair of walls facing each other in the Y direction forming the amount portion 41) and the length in the width direction (Y direction) at the bottom of the concave portion (low basis weight portion 42) of the concavo-convex structure, and add them Is the calculated length. For the upper side L4, the contour path length is measured in the same manner as the lower side L5.

  As described above, the space 6 formed by the concave portion (low basis weight portion 42) of the concave-convex structure on the back sheet 3 side and the back sheet 3 is, as shown in FIGS. It consists of a plurality of spaces 6X extending continuously in the longitudinal direction X and a plurality of spaces 6Y extending continuously in the width direction Y. In the absorbent article 1, the low basis weight portion 42 in the intersecting region 6XY between the space 6X extending in the longitudinal direction X and the space 6Y extending in the width direction Y is the center of the intersecting region 6XY as shown in FIG. The thickness is the thinnest in the part. More specifically, the low basis weight portion 42X (concave portion) forming the space 6X continuously extending in the longitudinal direction X is formed in an arc shape at the bottom of the concave portion as shown in FIG. 4B. The low basis weight portion 42Y (concave portion) that forms the space 6Y continuously extending in the width direction Y is also formed in an arc shape at the bottom of the concave portion in a cross-sectional view. In the intersection region 6XY between the space 6Y in the width direction 6X and the space 6Y, the central portion is most concave on the surface sheet 2 side, and the central portion is thicker than the boundary between the adjacent convex portions (high basis weight portion 41). The thickness is the smallest among the low basis weight portions 42. With such a configuration, the absorbed liquid quickly penetrates the space 6X in the longitudinal direction X and the space 6Y in the width direction Y through the intersecting region 6XY, quickly absorbs the liquid from the top sheet 2, and is excellent for the wearer. An effect of providing a dry feeling can be achieved.

  In particular, in the absorbent body 4 of the absorbent article 1, as described above, the surface side concave portion 43 </ b> X is formed corresponding to the low basis weight portion 42 </ b> X that forms the concave portion in the longitudinal direction X, and the concave portion in the width direction Y is formed. As shown in FIG. 4B, the surface-side recess 43X has an arc shape at the bottom of the surface-side recess 43X, as shown in FIG. 4B. The surface side recess 43Y is also formed in an arc shape at the bottom of the recess as viewed in cross section. Therefore, in the intersecting region between the front-side concave portion 43X in the longitudinal direction X and the front-side concave portion 43Y in the width direction Y, the central portion is most concave on the back sheet 3 side. Therefore, the distance between the central portion in the intersecting region between the surface-side concave portion 43X and the surface-side concave portion 43Y and the central portion in the intersecting region 6XY between the space 6X in the longitudinal direction X and the space 6Y in the width direction Y is the largest. It is short and the thickness of the central part in the intersection area 6XY is the thinnest in the low basis weight part 42. With such a configuration, the moisture existing between the absorbent article 1 and the wearer's skin can be absorbed through the intersecting region 6XY, and the effect of making the wearer less likely to feel stuffiness can be achieved.

  Below, the manufacturing method of the absorber 4 (absorbent core 40) with which the absorbent article 1 is provided is demonstrated. FIG. 5 shows an embodiment of a method for manufacturing the absorbent body 4 and a manufacturing apparatus used therefor. The manufacturing apparatus of the absorber 4 includes a rotary drum 50 that is rotationally driven in the direction of the arrow R1, a duct 60 that supplies the absorbent material 45 that is a raw material of the absorbent core 40 to the outer peripheral surface of the rotary drum 50, and the rotary drum 50. , A transfer roll 70 that is rotationally driven in the direction of arrow R2, a vacuum box 65 that is disposed between the duct 60 and the transfer roll 70 in the circumferential direction of the rotary drum 50, and a vacuum box 65 that rotates. A mesh belt 75, which is a sheet-like air-permeable member, disposed between the drum 50 and between the transfer roll 70 and the rotary drum 50; a vacuum conveyor 80 disposed below the transfer roll 70; It has.

  As shown in FIG. 5, the rotating drum 50 has a cylindrical shape, and receives power from a motor such as a motor, so that members forming the outer peripheral surface rotate around a horizontal axis. A space 56 capable of depressurizing the inside is formed in a non-rotating portion inside the rotating drum 50 (on the rotating shaft side). A known exhaust device (not shown) such as an intake fan is connected to the space 56, and the interior of the space 56 can be maintained at a negative pressure by operating the exhaust device. On the other hand, piping (not shown) capable of taking in air outside the apparatus is connected to the spaces 57 and 58 on the inner side (rotating shaft side) of the rotating drum 50.

  As shown in FIG. 5, a drum recess 51 having a shape corresponding to the shape of the absorbent core 40 to be manufactured is formed on the outer peripheral surface of the rotary drum 50. A large number of pores are formed in the bottom surface portion 52 of the drum concave portion 51, and while the drum concave portion 51 passes over the space 56 maintained at a negative pressure, the fineness of the bottom surface portion 52 of the drum concave portion 51 is reduced. The holes function as suction holes for the absorbent material 45. On the other hand, the left and right side portions of the outer peripheral surface of the rotating drum 50 where the drum recess 51 is not formed are made of a frame body of the rotating drum 50 made of a metal rigid body and are non-breathable.

  As shown in FIG. 6, a plurality of partition members 53 that partition the inside of the drum recess 51 into a plurality of regions are formed on the bottom surface portion 52 of the drum recess 51. Each partition member 53 is made of a non-breathable plate member. The inside of the drum recess 51 is partitioned into a plurality of regions 54 corresponding to the plurality of high basis weight portions 41 in the absorbent core 40 described above by a plurality of partition members 53. The shape of each partition region 54 in plan view is the same shape (rectangular shape) as that of the high basis weight portion 51 in plan view. Further, as will be described later, in order to allow the absorbent material to be deposited in the drum recess 51 beyond the protruding height from the bottom surface portion 52 of the partition member 53, the protruding height from the bottom surface portion 52 of the partition member 53. This is shorter than the depth of the drum recess 51.

  As shown in FIG. 5, one end side of the duct 60 covers the outer peripheral surface of the rotary drum 50 positioned on the space 56 maintained at a negative pressure, and the other end side (not shown) has a fiber material introduction device. have. The fiber material introducing device includes, for example, a pulverizer that pulverizes sheet-like wood pulp into defibrated pulp and feeds the defibrated pulp (fiber material) into a duct. A water-absorbing polymer introduction part that introduces the water-absorbing polymer may be provided in the middle of the duct 60.

  The transfer roll 70 has a cylindrical outer peripheral portion having air permeability, and the outer peripheral portion rotates around a horizontal axis when receiving power from a prime mover such as a motor. In the non-rotating portion on the inner side (rotating shaft side) of the transfer roll 70, a space 71 that can be depressurized is formed. A known exhaust device (not shown) such as an intake fan is connected to the space 71, and the interior of the space 71 can be maintained at a negative pressure by operating the exhaust device.

  The vacuum box 65 is disposed between the downstream end 61 of the duct 60 and the transfer roll 70 in the rotation direction R1 of the rotary drum 50. The vacuum box 65 has a box-like shape having upper and lower surfaces, left and right side surfaces, and a back surface, and has an opening that opens toward the rotary drum 50 at a portion facing the back surface. The vacuum box 65 is connected to a known exhaust device (not shown) such as an intake fan via an exhaust pipe 61, and the inside of the vacuum box 65 can be maintained at a negative pressure by the operation of the exhaust device. .

  The mesh belt 75 is a sheet-like air-permeable member, which is formed by connecting a belt-like air-permeable belt having a mesh in an endless manner, and is guided by a plurality of free rolls and transfer rolls 70 so as to continue a predetermined path. Move on. The mesh belt 75 is driven by the rotation of the transfer roll 70. As shown in FIG. 5, the mesh belt 75 is introduced between the vacuum box 65 and the rotary drum 50 and the transfer roll after being introduced onto the outer peripheral surface of the rotary drum 50 in the vicinity of the downstream end portion 61 of the duct 60. 70 and the rotating drum 50 are arranged so as to pass sequentially. While the mesh belt 75 passes in front of the opening of the vacuum box 65, the mesh belt 75 is in contact with the outer peripheral surface of the rotary drum 50, and the transfer roll 70 and the rotary drum 50 are closest to each other. In the vicinity of the portion, the transfer drum 70 moves away from the outer peripheral surface of the rotating drum 50.

  The vacuum conveyor 80 includes an endless breathable belt 83 that is stretched between the drive roll 81 and the driven roll 82, and a vacuum box 84 that is disposed at a position facing the transfer roll 70 with the breathable belt 83 interposed therebetween. ing.

  Next, a method for continuously manufacturing the absorbent body 4 (absorbent core 40) using the above-described absorbent body manufacturing apparatus will be described. In order to manufacture the absorber 4 using the above-described absorber manufacturing apparatus, the exhaust device connected to each of the space 56 in the rotary drum 50 and the vacuum box 65 is operated to make negative pressure. . By making negative pressure in the space 56, an air flow is generated in the duct 60 to convey the absorbent material 45 to the outer peripheral surface of the rotary drum 50. Further, the rotating drum 50 and the transfer roll 70 are rotated, and the vacuum conveyor 80 is operated. Then, when the fiber material introduction device is operated to supply the fiber material into the duct 60 and further supply the water-absorbing polymer, these absorbent materials 45 ride on the air flow flowing through the duct 60 and scatter. The state is supplied toward the outer peripheral surface of the rotating drum 50.

  While the portion covered with the duct 60 is being conveyed, the absorbent material (mixture of fiber material and water-absorbing polymer) 45 is sucked into the drum recess 51 of the rotary drum 50. The absorbent material 45 is gradually deposited on the bottom surface portion 52 of each partition region 54 of the drum recess 51, and finally, as shown in FIG. And deposits in the drum recess 51. In the deposit 46 obtained in this way, the part (partition member corresponding part) 46a formed by depositing the absorbent material 45 on the partition member 53 has a relatively small amount of deposited absorbent material 45, and other parts. (Partition region corresponding part) 46b has a relatively large amount of deposited absorbent material 45, and the entire deposit 46 has an uneven structure.

  Then, when the rotary drum 50 rotates and the drum concave portion 51 comes to the position opposite to the vacuum box 65, the deposit 46 in the drum concave portion 51 is sucked to the mesh belt 75 by the suction from the vacuum box 65. It becomes. In this state, the deposit 46 in the drum recess 51 is conveyed to a position immediately before the closest portion between the transfer roll 70 and the rotary drum 50, and is sucked from the transfer roll 70 side in the vicinity of the closest portion to the mesh belt. The mold is released from the drum recess 51 while being sucked by 75 and moved onto the transfer roll 70.

  Thus, the deposit 46 that has moved onto the transfer roll 70 together with the mesh belt 75 is conveyed to the transfer section (the lowermost end of the transfer roll 70) with the vacuum conveyor 80 while being adsorbed by the mesh belt 75 on the transfer roll 70. Then, in the transfer section, the vacuum box 84 moves to the vacuum conveyor 80 by suction.

  In the absorbent body manufacturing apparatus of the present embodiment, as shown in FIG. 5, the first core wrap sheet 47 made of tissue paper or water-permeable nonwoven fabric is placed on the vacuum conveyor 80 before the deposit 46 is placed. Is introduced, and the deposit 46 moves onto the first core wrap sheet 47. Further, after the second core wrap sheet 48 is introduced on the upper surface side of the deposit 46, the deposit 46 covered with both the core wrap sheets 47, 48 is cut at a predetermined interval to obtain one napkin. The absorber precursor 49 cut to the minute dimension is obtained. In addition, in FIG.1 and FIG.2, illustration of both the core wrap sheets 47 and 48 is abbreviate | omitted.

  And in the absorber manufacturing apparatus of this embodiment, the absorber precursor 49 obtained in this way is compressed by the pressurizing means 90, and the thickness of the deposit 46 which comprises the absorber precursor 49 is actively reduced. Thus, the intended absorber 4 (absorbent core 40) is obtained. As shown in FIG. 5, the pressurizing means 90 includes a pair of rolls 91 and 92 having a smooth surface, and the object to be pressurized introduced between the rolls 91 and 92 can be compressed from the upper and lower surfaces and compressed in the thickness direction. It is configured.

  FIG. 8 schematically shows the state of the deposit 46 before and after compression. The left diagram across the arrow in FIG. 8 shows the deposit 46 before compression, the right diagram shows the deposit 46 (absorbent core 40) after compression, and in both the left and right diagrams, the upper part shows the deposit 46 ( The cross-sectional view of the absorbent core 40), the lower part shows a perspective view of the deposit 46. When the deposit 46 is compressed by the pressurizing means 90, the partition region corresponding portion 46b (convex portion) having a relatively large absorbent material and a large thickness has a partition member corresponding portion 46a having a relatively small absorbent material and a small thickness. It is compressed more strongly than (non-convex part or concave part). As a result, the partition region corresponding portion 46b (convex portion) in the deposit 46 becomes a high basis weight portion 41 having a relatively high density in the absorbent core 40, and the partition member corresponding portion 46a (concave portion) in the deposit 46 is In the absorbent core 40, a low basis weight portion 42 having a relatively low density is obtained. Further, when the absorbent core 40 formed in this way is used in an absorbent article, if the low basis weight portion 42 (concave portion) is arranged on the top sheet 2 side, the bottom portion of the low basis weight portion 42 (concave portion) is the back sheet. The surface side recess 43 is formed on the surface on the surface sheet 2 side.

The forming material in the absorbent article 1 will be described.
As the top sheet 2, various types conventionally used in the technical field can be used without particular limitation. As the surface sheet 2, for example, a liquid-permeable sheet such as a nonwoven fabric or an apertured film can be used.
As the absorbent material 45 which is a material for forming the absorbent core 40, various materials conventionally used in the technical field can be used without particular limitation. For example, as a fiber material, wood pulp, cotton, hemp, etc. Natural fibers; synthetic fibers made of synthetic resins such as polyethylene and polypropylene; semi-synthetic fibers such as acetate and rayon can be used. Further, in addition to these fiber materials, water-absorbing polymers of various shapes such as particles can be used as the absorbent material.

As the back sheet 3, a moisture permeable sheet having moisture permeability is used. Examples of moisture permeable sheets include sheets having a large number of fine pores and high water vapor permeability, such as inorganic powders such as calcium carbonate and barium sulfate, and incompatible organic polymers such as nylon and polystyrene. A sheet having fine pores and having a high water vapor permeability, which is obtained by uniaxially or biaxially stretching a polyethylene film kneaded with bismuth, is preferably used. Specifically, a basis weight obtained by stretching a polyethylene film having a basis weight of 20 to 50 g / m ² containing 30 to 60% by weight of calcium carbonate having an average particle size of 0.5 to 1.0 μm in the MD direction twice. A moisture permeable film of 13 to 28 g / m ² is exemplified. As the moisture permeable sheet, a water repellent nonwoven fabric or a composite sheet of the above sheet and the water repellent nonwoven fabric may be used.

In the case where the absorbent article 1 is used for a sanitary napkin, the absorbent article 1 has a sufficient ventilation rate to quickly exhaust moisture existing between the wearer's skin and the sanitary napkin surface, and is fine enough to allow air to pass through. The moisture permeability of the moisture permeable sheet used for the back sheet 3 is 0.5 to 3.0 g / 100 cm ² · hr from the viewpoint that it is necessary to have a sufficient water pressure resistance so that menstrual blood does not ooze out from the pores. It is preferable that it is 1.0 to 2.0 g / 100 cm ² · hr.
In the case where the absorbent article 1 is used in a disposable diaper, it is necessary to quickly evaporate a large amount of moisture generated from urine from the inside of the disposable diaper. For this reason, the moisture permeability of the moisture permeable sheet used for the back sheet 3 is 1.2 to 3.0 g / from the viewpoint that sufficient water pressure resistance is easily expressed even if there are many fine holes in the back sheet 3. It is preferably 100 cm ² · hr, more preferably 0.7 to 4.0 g / 100 cm ² · hr.

The effect at the time of using the absorbent article 1 of embodiment of this invention mentioned above is demonstrated.
As shown in FIG. 2, the absorbent body 4 included in the absorbent article 1 includes an integrally formed high basis weight portion 41 (convex portion) and low basis weight portion 42 (low basis weight portions 42 </ b> X, 42 </ b> Y) (concave portion). The low basis weight portion 42 (low basis weight portions 42X and 42Y) is unevenly distributed on the top sheet 2 side, and has an uneven structure on the back sheet 3 side of the absorbent body 4. Thus, since the high basic weight part 41 and the low basic weight part 42 (low basic weight part 42X, 42Y) are integrally molded, the low basic weight unevenly distributed in the surface sheet 2 side at the time of use of the absorbent article 1 is used. The body fluid easily moves from the portion 42 (low basis weight portions 42X, 42Y) to the high basis weight portion 41, and the absorbent body 4 of the absorbent article 1 has the high basis weight portion 41 and the low basis weight portion 42 (low basis weight). Part 42X, 42Y), the length of the lower side L5 on the back sheet 3 side is longer than the length of the upper side L4 on the side of the top sheet 2, that is, the back sheet 3 of the absorber 4. The surface area of the surface on the side is larger than the surface area of the surface on the surface sheet 2 side, and the vapor divergence amount on the back sheet 3 side is likely to increase. Moreover, the space 6X formed by the concave portion (low basis weight portion 42 (low basis weight portion 42X)) and the moisture-permeable back sheet 3 in the uneven structure on the back sheet 3 side of the absorbent body 4 is continuous in the longitudinal direction X. Therefore, moisture in the wearing during use is easily diffused with the space 6X as a passage. Therefore, according to the absorbent article 1, it is possible to effectively reduce the humidity in the wearing at the time of use, reduce the wet feeling, and give a comfortable wearing feeling.

  In particular, in the absorbent article 1, the high basis weight portion 41 (convex) is formed at a higher density than the low basis weight portion 42 (42X, 42Y) (concave portion). Sometimes, the body fluid is more likely to move from the low basis weight portion 42 (low basis weight portions 42X, 42Y) unevenly distributed on the surface sheet 2 side to the high basis weight portion 41. The high basis weight portion 41 has a relatively high absorption capacity with respect to the low basis weight portion 42 and has a high density, and therefore absorbs liquid faster than the low basis weight 42. For this reason, the low basis weight portion 42 is less likely to swell than the high basis weight portion 41, and thus is less likely to swell and is adjacent to the enemy basis weight portion even after the absorber 4 has absorbed a relatively large amount of liquid. The spaces 6X and 6Y are not lost. In particular, in the absorbent article 1, the space 6 </ b> Y formed by the concave portion (low basis weight portion 42 (low basis weight portion 42 </ b> Y)) and the moisture-permeable back sheet 3 also extends continuously in the width direction Y. Therefore, the moisture in the wearing during use is more easily diffused from both side edges of the product, with the space 6Y having a shorter moving passage as a passage.

  Moreover, as shown to Fig.4 (a), the absorber 4 with which the absorbent article 1 is provided has surface side recessed part 43X, 43Y corresponding to the recessed part (low basic weight part 42X, 42Y) (recessed part) of an uneven structure. Since it has, it is easy to bend | bend in any direction of the skin contact surface side and the non-skin contact surface side, and it is easy to deform | transform more complicatedly. For this reason, since the absorbent article 1 is flexibly deformed along the wearer's complex body line, it provides the wearer with an excellent feeling of wear and improves fit and provides excellent leakage prevention.

The absorbent article of the present invention is not limited to the above embodiment.
For example, in the embodiment, in the absorbent core 40 of the absorbent body 4, the high basis weight portion 41 is arranged at substantially equal intervals in the longitudinal direction X and the width direction Y as shown in FIGS. 1 and 3. However, if the space 6X formed by the concave portion (low basis weight portion 42 (low basis weight portion 42X)) and the moisture-permeable back sheet 3 in the concavo-convex structure extends continuously in the longitudinal direction X, The high basic weight portions 41 may be arranged in a zigzag pattern. That is, a large number of high basis weight portions 41 are arranged at predetermined intervals in the longitudinal direction X to form a high basis weight portion row, and a plurality of high basis weight portion rows are arranged at predetermined intervals in the width direction Y. In this case, the pitches of the high basis weight portions 41 in the high basis weight portion rows adjacent to each other may be shifted. In other words, the high basis weight portion 41 is adjacent to the high basis weight portion 41 when projected in a direction (width direction Y) orthogonal to the high basis weight portion row in the predetermined high basis weight portion row. You may arrange | position so that it may not correspond with the projection image of the basic weight part 41. FIG.

DESCRIPTION OF SYMBOLS 1 Absorbent article 2 Top sheet 3 Back sheet 4 Absorber 40 Absorbent core 41 High basis weight part (convex part)
42, 42X, 42Y Low basis weight part (recess)
5 Peripheral seal portion 6, 6X, 6Y Space 6XY Intersection region 10 Absorbent body 45 Absorbent material 46 Deposit 49 Absorber precursor 50 Rotating drum 51 Drum recess 52 Bottom surface portion 53 Partition member 54 Partition region 60 Duct 65 Vacuum box 70 Transfer roll 75 Mesh belt 80 Vacuum conveyor

Claims (6)

A longitudinal sanitary napkin comprising a top sheet disposed on the skin facing surface side, a back sheet disposed on the non-skin facing surface side, and a longitudinal absorbent body interposed between both sheets,
The back sheet has moisture permeability,
The absorbent body has a high basis weight part having a relatively high basis weight and a low basis weight part having a relatively low basis weight adjacent to the high basis weight part, The low basis weight part is integrally molded, and the concave-convex structure in which the convex part that is the high basic weight part and the concave part that is the low basic weight part are alternately arranged on the back sheet side of the absorber. Formed, and on the surface sheet side of the absorber, the low basis weight portion is unevenly distributed, the concave portion is recessed on the surface sheet side, and the convex portion is convex on the back sheet side,
The space formed by the recess and the back sheet extends continuously in at least the longitudinal direction ,
The absorbent core constituting the absorbent body has a cross-sectional view in the width direction, and the length L5 of the lower side contour path of the back sheet side is 2 to 4 of the upper side contour path length L4 of the top sheet side. A sanitary napkin that is doubled . The sanitary napkin according to claim 1, wherein the concave portion is arranged so as to surround the convex portion, and the space continuously extends in each of a longitudinal direction and a width direction. The absorber has, on the surface sheet side of the absorber, a surface-side recess that is recessed on the backsheet side, corresponding to the recess of the uneven structure on the backsheet side,
The sanitary napkin according to claim 1 or 2, wherein the depth of the recess is deeper than the depth of the surface-side recess. The sanitary napkin according to any one of claims 1 to 3, wherein the high basis weight part has a higher density than the low basis weight part. The space continuously extends in each of the longitudinal direction and the width direction, and the low basis weight portion in the intersection region between the space extending in the longitudinal direction and the space extending in the width direction is the thickest in the central portion of the intersection region. The sanitary napkin according to any one of claims 2 to 4, wherein the sanitary napkin is thin. The sanitary napkin according to any one of claims 2 to 5, wherein the high basis weight portion forming the convex portion has a corner formed in an arc shape in plan view.

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