JP2019141304A - Sheet member for absorbent article, and absorbent article - Google Patents

Abstract

To effectively utilize a superabsorbent material.SOLUTION: An absorbing core 22 comprises a lower side sheet 221, an upper side sheet 222, and a superabsorbent material 226. The lower side sheet 221 extends in a longitudinal direction. The upper side sheet 222 is a film formed in such a manner that a plurality of water passage holes 26 are dispersed, and joined to the lower side sheet 221. The superabsorbent material 226 is arranged between the lower side sheet 221 and the upper side sheet 222, and fixed to at least one of the lower side sheet 221 and the upper side sheet 222. In the absorbing core 22, liquid of excrement can be appropriately diffused by the upper side sheet 222, and most of the superabsorbent material 226 can be effectively utilized.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a sheet member for absorbent articles and an absorbent article.

  Conventionally, absorbent articles, such as a disposable diaper, are utilized. In such an absorbent article, the absorption amount is improved by arranging an absorbent core containing a superabsorbent material in a portion that receives urine from a wearer. For example, an absorption core generally has a structure in which a superabsorbent material is sandwiched between nonwoven fabrics (see Patent Document 1, for example, as such an absorption core).

Japanese Patent No. 5746686

  By the way, in a structure in which a superabsorbent material is sandwiched between non-woven fabrics, liquid diffusibility in the non-woven fabric is low, so that liquid such as urine excreted from the wearer is concentrated and applied to a part of the superabsorbent material. In this case, the portion of the superabsorbent material that has absorbed the liquid swells and becomes dense, and a phenomenon (also referred to as blocking) that prevents the liquid from penetrating into the absorbent core is likely to occur. As a result, in the absorbent core, it is not possible to effectively use the highly absorbent material (that is, reduce waste).

  This invention is made | formed in view of the said subject, and aims at utilizing a superabsorbent material effectively.

  Invention of Claim 1 is a sheet | seat member for absorbent articles, Comprising: It is the film formed by disperse | distributing and forming the 1st sheet | seat extended in a longitudinal direction, and several water flow holes, It joins to the said 1st sheet | seat A second sheet, and a superabsorbent material disposed between the first sheet and the second sheet and fixed to at least one of the first sheet and the second sheet.

  Invention of Claim 2 is a sheet | seat member for absorbent articles of Claim 1, Comprising: When the said sheet | seat member for absorbent articles is used in an absorbent article, the said 2nd sheet | seat is said 1st. It is arranged closer to the wearer than one sheet.

  Invention of Claim 3 is a sheet | seat member for absorbent articles of Claim 1 or 2, Comprising: In the said 2nd sheet | seat, the hole edge part in each of these water flow holes is said 1st. Projects toward the seat.

  Invention of Claim 4 is a sheet | seat member for absorbent articles of Claim 3, Comprising: In the said hole edge part, the magnitude | size of the hole in a front-end | tip part is smaller than a root part.

  Invention of Claim 5 is a sheet | seat member for absorbent articles as described in any one of Claim 1 thru | or 4, Comprising: Between the said 1st sheet | seat and the said 2nd sheet | seat, the said superabsorbency A low density region where the density of the material is lower than the surrounding area or where the superabsorbent material is not present extends along the longitudinal direction.

  Invention of Claim 6 is a sheet | seat member for absorbent articles of Claim 3 or 4, Comprising: Between the said 1st sheet | seat and the said 2nd sheet | seat, the density of the said super absorbent material is circumference | surroundings. A low density region that is lower than the above or the absence of the superabsorbent material extends along the longitudinal direction, and the hole edge is crushed in the low density region, the first sheet And the second sheet are joined.

  Invention of Claim 7 is a sheet | seat member for absorbent articles as described in any one of Claim 1 thru | or 6, Comprising: The diameter of these water flow holes is 0.1 mm or more, and 3 millimeters or less.

  Invention of Claim 8 is a sheet | seat member for absorbent articles as described in any one of Claim 1 thru | or 7, Comprising: It joins to the said 2nd sheet | seat on the opposite side to a said 1st sheet | seat. A third sheet, and another superabsorbent material disposed between the second sheet and the third sheet and fixed to at least one of the second sheet and the third sheet.

  Invention of Claim 9 is a sheet | seat member for absorbent articles of Claim 8, Comprising: When the said sheet | seat member for absorbent articles is used in an absorbent article, the said 3rd sheet | seat is said 1st. A lower absorbent layer is formed by the superabsorbent material disposed between the first sheet and the second sheet, and is disposed closer to the wearer than the first sheet, and the second sheet and the third sheet. An upper absorbent layer is formed by the other superabsorbent material disposed between the upper absorbent layer and the absorption rate of the superabsorbent material in the lower absorbent layer is the other superabsorbent material in the upper absorbent layer. Bigger than.

  The invention described in claim 10 is the sheet member for absorbent articles according to claim 8 or 9, wherein the third sheet is a film formed by dispersing a plurality of water passage holes.

  Invention of Claim 11 is an absorbent article which receives excrement from a wearer, Comprising: The sheet | seat member for absorbent articles as described in any one of Claim 1 thru | or 10, For the said absorbent article A top sheet covering the main surface of the seat member on the wearer side, and a back sheet covering the other main surface of the sheet member for absorbent articles.

  According to the present invention, the liquid of excrement can be appropriately diffused by the second sheet, and the superabsorbent material can be effectively used.

It is a top view which shows an absorbent article. It is sectional drawing which shows an absorbent article. It is a top view which shows an absorption core. It is a figure which expands and shows the cross section of an absorption core. It is a figure which shows the other example of an absorption core. It is a figure which expands and shows the cross section of an absorption core. It is a figure which shows the other example of an absorption core. It is a figure which shows the other example of an absorption core.

  FIG. 1 is a plan view showing the absorbent article 1 according to one embodiment of the present invention in an unfolded state. The absorbent article 1 is an auxiliary absorbent pad that is attached to the inside of an exterior article such as a disposable diaper worn by the wearer (that is, the wearer side) and receives excrement such as urine from the wearer. In FIG. 1, the absorbent article 1 is drawn with the surface on the side in contact with the wearer at the time of wearing facing forward.

  FIG. 2 is a cross-sectional view of the absorbent article 1 cut along a plane perpendicular to the longitudinal direction (that is, the vertical direction in FIG. 1) at the position II-II shown in FIG. As shown in FIGS. 1 and 2, the absorbent article 1 is disposed on a substantially sheet-like main body 2 and on both sides of the main body 2 (that is, on both sides in the width direction perpendicular to the longitudinal direction). A pair of side seats 3 is provided over the entire length of the main body 2 in the longitudinal direction.

  As shown in FIGS. 1 and 2, the main body 2 is disposed between a liquid-permeable top sheet 21, a water-repellent or liquid-impervious back sheet 23, and the top sheet 21 and the back sheet 23. And a substantially sheet-shaped absorbent core 22. The absorbent core 22 is a sheet member for absorbent articles used in the absorbent article 1 and is also called a polymer sheet. In FIG. 2, for convenience of illustration, the components of the absorbent article 1 are drawn apart in the thickness direction (the same applies to FIGS. 4 to 8 described later). In FIG. 1, the outline of the absorbent core 22 is drawn with a thick broken line in order to facilitate understanding of the drawing. As shown in FIG. 1, each of the absorbent core 22 and the main body 2 is a substantially rectangular shape that is long in the longitudinal direction in plan view. The main body 2 is slightly larger than the absorbent core 22, and the entire absorbent core 22 is located inside the outer peripheral edge of the main body 2.

  The length in the longitudinal direction and the width in the width direction (hereinafter simply referred to as “length” and “width”) of the top sheet 21 and the back sheet 23 are larger than the length and width of the absorbent core 22. As shown in FIG. 2, the top sheet 21 covers the main surface of the absorbent core 22 on the wearer side. The back sheet 23 covers the other main surface of the absorbent core 22, that is, the main surface on the side opposite to the wearer. The top sheet 21 is joined to the back sheet 23 via a hot melt adhesive or the like around the absorbent core 22.

  As shown in FIG. 2, the absorbent core 22 includes a liquid-permeable lower sheet 221, a liquid-permeable upper sheet 222, and a superabsorbent material 226. The lower sheet 221 and the upper sheet 222 are overlapped with each other and bonded by a hot melt adhesive or the like. Thereby, a sheet laminate in which a plurality of sheet members are laminated is formed. The superabsorbent material 226 is disposed between the lower sheet 221 and the upper sheet 222. Superabsorbent material 226 in this embodiment includes a large number of particles. In the present specification, “upper side” and “lower side” are for convenience, and do not necessarily mean the direction of gravity. Details of the structure of the absorbent core 22 will be described later.

  The top sheet 21 is a liquid-permeable sheet member that quickly captures the excrement liquid from the wearer and moves it to the absorbent core 22. The absorbent core 22 absorbs the liquid that has passed through the top sheet 21 and quickly fixes it. The backsheet 23 prevents excrement liquid or the like that has reached the backsheet 23 from oozing out of the main body 2.

  As shown in FIGS. 1 and 2, each side sheet 3 includes a side sheet main body 31 and a side wall elastic member 32 that is joined to the side sheet main body 31 with a hot melt adhesive or the like and extends in the longitudinal direction. As shown in FIG. 2, the side seat body 31 is folded in two along a fold line 39 extending over the entire length in the longitudinal direction. In the side sheet main body 31, the band-shaped portion on one side of the fold line 39 is referred to as “side wall fixing portion 33”, and the band-shaped portion on the other side of the fold line 39 is referred to as “side wall portion 34”.

  The side wall fixing portion 33 is joined to the wearer-side surface of the main body 2 using a hot melt adhesive or the like over the entire length in the longitudinal direction in the vicinity of the side edge of the main body 2. The side wall portion 34 is a portion that is continuous from the side wall fixing portion 33 at a fold line 39 and extends over substantially the entire length of the main body portion 2 on both side portions of the main body portion 2. The side wall part 34 is overlapped on the main body part 2 at both ends in the longitudinal direction, and is fixed by a hot melt adhesive or the like. A side wall elastic member 32 is joined to the free end of the side wall 34. When the side wall elastic member 32 contracts, the central portion in the longitudinal direction of the side wall 34 rises from the main body 2 toward the wearer and becomes a pair of three-dimensional gathers that contact the vicinity of the base of the wearer's leg. . Thereby, in the absorbent article 1, leakage of urine or the like from around the legs is suppressed.

  As the above-mentioned hot melt adhesive, those of polyolefin type, rubber type, vinyl acetate type and the like are used. The bonding between the top sheet 21 and the back sheet 23 and the bonding between the side sheet 3 and the main body 2 may be performed by heat fusion bonding, ultrasonic bonding, or the like.

  As the top sheet 21, for example, a liquid-permeable non-woven fabric formed of hydrophobic fibers (polypropylene, polyethylene, polyester, polyamide, nylon, etc.) whose surface is hydrophilically treated with a surfactant is used. The said nonwoven fabric is a point bond nonwoven fabric, an air through nonwoven fabric, and a spun bond nonwoven fabric, for example. In addition, as the top sheet 21, a nonwoven fabric (for example, a spunlace nonwoven fabric) formed of hydrophilic fibers such as cellulose, rayon, or cotton may be used.

  As the back sheet 23, a water-repellent or liquid-impervious nonwoven fabric (for example, a spunbond nonwoven fabric, a meltblown nonwoven fabric, an SMS (spunbond / meltblown / spunbond) nonwoven fabric) formed of hydrophobic fibers, A liquid-impermeable plastic film or a laminated sheet in which these nonwoven fabrics and plastic films are laminated is used. From the viewpoint of preventing wear of the absorbent article 1 and improving the comfort of the wearer, the plastic film used in the back sheet 23 preferably has moisture permeability (breathability).

  As the side sheet main body 31, a water-repellent or liquid-impervious nonwoven fabric (for example, a spunbond nonwoven fabric, a melt blown nonwoven fabric, an SMS nonwoven fabric, or the like) formed of hydrophobic fibers is used. As the side wall elastic member 32, for example, a polyurethane thread, a strip-shaped polyurethane film, a thread-shaped or strip-shaped natural rubber, or the like is used. In the absorbent article 1 shown in FIG. 1, the polyurethane thread is used as an elastic member.

  FIG. 3 is a plan view showing the absorbent core 22. As described above, the absorbent core 22 has a substantially rectangular shape that is long in the longitudinal direction, and the lower sheet 221 and the upper sheet 222 both have a shape extending in the longitudinal direction. In the absorption core 22, a plurality of material existence regions 28 and a plurality of material non-existence regions 29 are provided. The plurality of material existence regions 28 indicated by parallel oblique lines in FIG. 3 are strips each extending substantially parallel to the longitudinal direction, and are arranged while being separated from each other in the width direction. That is, the absorbent core 22 is provided with a plurality of material existence regions 28 arranged in a stripe shape extending in the longitudinal direction. In the example of FIG. 3, the widths of the plurality of material existence regions 28 are approximately equal to each other.

  In the material presence region 28, a hot-melt adhesive or the like is applied to one or both of the lower sheet 221 and the upper sheet 222 by, for example, spiral coating or curtain coating, and the superabsorbent material 226 is fixed. . That is, in the material presence region 28, the superabsorbent material 226 is sandwiched between the lower sheet 221 and the upper sheet 222. As the superabsorbent material 226, for example, a granular superabsorbent polymer (SAP (Super Absorbent Polymer)) or a fibrous superabsorbent fiber (SAF (Super Absorbent Fiber)) is used. The superabsorbent material 226 in the present embodiment is a granular superabsorbent polymer.

  The plurality of material non-existing regions 29 are regions excluding the plurality of material existing regions 28 in the absorbent core 22. Each material non-existence area | region 29 is strip | belt shape extended along a longitudinal direction. For example, the width of the material non-existing region 29 is smaller than the width of the material existing region 28. In the example of FIG. 3, the widths of the plurality of material non-existing regions 29 are equal to each other. The plurality of material non-existing regions 29 and the plurality of material existing regions 28 are alternately arranged in the width direction.

  In each material non-existence region 29, no superabsorbent material exists between the lower sheet 221 and the upper sheet 222. In the material absence region 29, it is preferable that the lower sheet 221 and the upper sheet 222 are bonded to each other by bonding without using an adhesive such as heat fusion bonding or bonding by embossing. In the material absence region 29, the lower sheet 221 and the upper sheet 222 may be partially unbonded. Further, the material non-existence region 29 may be a region containing a slight amount of superabsorbent material. In other words, the material non-existence region 29 may be a low-density region where the density of the high-absorbency material 226 is lower than that of the surroundings (here, the material-existence region 28) or the high-absorption material 226 is not present.

  As shown in FIG. 2, in the absorbent article 1, the lower sheet 221 is disposed between the upper sheet 222 and the back sheet 23. That is, in the absorbent article 1, the lower sheet 221 is disposed outside the upper sheet 222 and the superabsorbent material 226. As the lower sheet 221, for example, as with the top sheet 21, a liquid-permeable nonwoven fabric formed of hydrophobic fibers (polypropylene, polyethylene, polyester, polyamide, nylon, etc.) whose surface is subjected to a hydrophilic treatment with a surfactant. Is used. The said nonwoven fabric is a point bond nonwoven fabric, an air through nonwoven fabric, and a spun bond nonwoven fabric, for example. Moreover, as the lower sheet 221, a nonwoven fabric (for example, spunlace nonwoven fabric) formed of hydrophilic fibers such as cellulose, rayon, or cotton may be used. Furthermore, as the lower sheet 221, a tissue, a plastic film, or the like may be used.

  FIG. 4 is an enlarged view showing a cross section of the absorbent core 22 in the material existence region 28. In FIG. 4, the particles of the superabsorbent material 226 are indicated by circles with parallel diagonal lines inside. As described above, the particles of the superabsorbent material 226 are fixed to at least one of the lower sheet 221 and the upper sheet 222 with a hot melt adhesive or the like.

  As shown in FIG. 2, the upper sheet 222 is disposed between the lower sheet 221 and the top sheet 21. That is, in the absorbent article 1, the upper sheet 222 is disposed closer to the wearer than the lower sheet 221. The upper sheet 222 is a perforated film, and as shown in FIG. 4, in the material presence region 28, a plurality of water passage holes 26 are formed in the upper sheet 222 in a dispersed manner. The said film is a plastic film, for example, and is formed with resin, such as a polypropylene, a polyethylene terephthalate, and polyethylene. The film has water repellency, for example. When viewed along the thickness direction of the absorbent core 22, each water passage hole 26 is substantially circular and is surrounded by an annular hole edge 261. That is, the water passage hole 26 is inside the hole edge portion 261. The shape of the water passage hole 26 may be a polygon such as a triangle. In addition, by adjusting the amount of the adhesive applied to the upper sheet 222, the adhesive is prevented or suppressed from filling the water passage hole 26.

  Each hole edge portion 261 protrudes toward the lower sheet 221. The hole edge portion 261 has a root portion 262 and a tip portion 263. The front end portion 263 is a portion of the hole edge portion 261 on the lower sheet 221 side. The root part 262 is a part of the hole edge 261 opposite to the lower sheet 221. In the hole edge portion 261, the size of the hole gradually decreases from the root portion 262 toward the tip end portion 263. Therefore, the size of the hole in the tip portion 263 is smaller than that of the root portion 262. Here, the size of the hole is a diameter obtained when the water passage hole 26 is approximated by a circle at each position in the thickness direction. In FIG. 4, the minimum hole size in the tip portion 263 in one water flow hole 26 is indicated by an arrow D1, and the maximum hole size in the root portion 262 is indicated by an arrow D2. In the hole edge portion 261, for example, a part of the tip end portion 263 may be missing.

  In each water passage hole 26, assuming that the smallest one of the sizes of the holes obtained at all positions in the thickness direction is the diameter of the water passage hole 26, the water passage in the material existence region 28 of the upper sheet 222. The diameter (average value) of the hole 26 is, for example, 0.1 mm (millimeter) or more. In the water passage hole 26, the liquid of excrement can pass. In order to facilitate the passage of the liquid, the diameter of the water passage hole 26 is preferably 0.3 mm or more. When the diameter of the water passage hole 26 is excessively large, particles of the highly absorbent material 226 (for example, a particle size of 0.3 to 0.5 mm) are likely to leak out of the absorption core 22 from the water passage hole 26. Therefore, the diameter of the water passage hole 26 is, for example, 3 mm or less. In order to further suppress the leakage of the particles of the superabsorbent material 226, the diameter of the water passage hole 26 is preferably 2.0 mm or less, and more preferably 1.0 mm or less.

In the manufacture of the film used for the upper sheet 222, for example, a plurality of heated needles are passed through a film in which no holes are formed. Thereby, a perforated film in which the plurality of water passage holes 26 are uniformly dispersed is formed and used as the upper sheet 222 in the absorbent core 22. In the upper sheet 222, the ratio of the area of the water passage holes 26 in the material existence region 28 (the area derived from the diameter of the water passage holes 26), that is, the area ratio of the water passage holes 26 in the perforated film is, for example, 10% or more. And 90% or less. In order to facilitate the passage of the liquid, the ratio of the area of the water passage holes 26 is preferably 20% or more, and more preferably 30% or more. In order to ensure a certain degree of strength in the upper sheet 222, the ratio of the area of the water passage holes 26 is preferably 80% or less, and more preferably 70% or less. In the perforated film, the number of water passage holes 26 per 1 cm ² is, for example, 7 or more and 80 or less.

  On the other hand, in the material non-existing region 29, the lower sheet 221 and the upper sheet 222 are joined in a state where the hole edge 261 in the perforated film is crushed. Therefore, the hole edge portion 261 does not clearly protrude toward the lower sheet 221 in the material absence region 29. By crushing the hole edge 261, many water holes 26 in the material non-existing region 29 are partially or totally blocked. Typically, the area ratio of the water passage holes 26 in the material non-existing region 29 is lower than that in the material existing region 28.

  When excrement such as urine is excreted from the wearer of the absorbent article 1, the excrement liquid passes through the top sheet 21 and adheres to the wearer side surface of the upper sheet 222. On the surface of the upper sheet 222, in the material presence region 28, the liquid is guided to the superabsorbent material 226 through the water passage holes 26 while diffusing in the longitudinal direction and the width direction. In the material non-existing region 29 extending in the longitudinal direction, the liquid spreads in the width direction while diffusing in the longitudinal direction, and is guided to the superabsorbent material 226 in the material existing region 28. In this way, the superabsorbent material 226 is effectively used over a wide range in the longitudinal direction and the width direction.

  Here, the absorption core of the comparative example in which both the lower sheet and the upper sheet are formed of a nonwoven fabric is assumed. In the absorbent core of the comparative example, since the liquid permeability of the upper sheet, which is a nonwoven fabric, is high, the liquid attached to the wearer side surface of the upper sheet does not diffuse so much in the upper sheet and concentrates on a part of the highly absorbent material. To be granted. In this case, the portion of the superabsorbent material that has absorbed the liquid swells and becomes dense, and a phenomenon (also referred to as blocking) that prevents the liquid from penetrating into the absorbent core is likely to occur. In addition, there may be a phenomenon (also referred to as a wetback) in which the liquid whose permeation has been blocked on the surface of the superabsorbent material returns to the wearer side through the upper sheet and adheres to the wearer's skin. Furthermore, in the upper sheet which is a nonwoven fabric, the liquid (liquid residue) held in the gaps between the fibers may cause discomfort to the wearer.

  On the other hand, in the absorbent core 22 of FIG. 4, a film formed by dispersing a plurality of water passage holes 26 is used as the upper sheet 222. In the upper sheet 222, the liquid can be appropriately diffused, and the liquid is prevented or suppressed from being concentrated and applied to a part of the superabsorbent material 226 like the absorbent core of the comparative example. Thereby, most of the superabsorbent material 226 in the absorbent core 22 can be used effectively (that is, waste is reduced), and the occurrence of blocking can also be suppressed. Moreover, since the upper sheet | seat 222 which is a film has liquid impermeability, it can suppress that the liquid which reached | attained the surface of the superabsorbent material 226 returns to a wearer side (wet back). Furthermore, since the liquid is not held in the upper sheet 222 that does not contain fibers, the liquid held in the upper sheet does not cause discomfort to the wearer as in the absorbent core of the comparative example.

  In the upper sheet 222, the hole edge 261 in each water passage hole 26 protrudes toward the lower sheet 221. Accordingly, it is possible to appropriately guide the liquid between the upper sheet 222 and the lower sheet 221 and to prevent the liquid that has passed through the water passage hole 26 from returning to the surface of the upper sheet 222. Further, in the hole edge portion 261, the size of the hole in the tip end portion 263 is smaller than that of the root portion 262, whereby the liquid that has passed through the water passage hole 26 can be further suppressed from returning to the surface of the upper sheet 222. . Depending on the design of the absorbent core 22, it is possible to use a film in which the hole edge 261 of the water passage hole 26 does not protrude.

  In the absorbent core 22, the material non-existing region 29 extends along the longitudinal direction. Thereby, the liquid can be appropriately diffused in the longitudinal direction using the material non-existing region 29. Moreover, in the material non-existence area | region 29, the lower sheet | seat 221 and the upper sheet | seat 222 are joined in the state by which the hole edge part 261 was crushed. Thereby, in the material non-existence area | region 29, the water flow hole 26 of the upper sheet | seat 222 can be partially or entirely obstruct | occluded, and the spreading | diffusion of the liquid in the longitudinal direction can further be promoted on the surface of the upper sheet | seat 222. .

  FIG. 5 is a view showing another example of the absorbent core, and shows a cross section of the absorbent core 22a perpendicular to the longitudinal direction. In the absorbent core 22 a of FIG. 5, an intermediate sheet 223 is added between the upper sheet 222 and the lower sheet 221. The lower sheet 221 is bonded to one surface of the intermediate sheet 223, and the upper sheet 222 is bonded to the surface of the intermediate sheet 223 opposite to the lower sheet 221. In addition, the first highly absorbent material 226 a is disposed between the lower sheet 221 and the intermediate sheet 223, and the second highly absorbent material 226 b is disposed between the intermediate sheet 223 and the upper sheet 222.

  Also in the absorption core 22a, a plurality of material existence regions 28 and a plurality of material non-existence regions 29 are provided as in the absorption core 22 of FIG. In each material existence region 28, the particles of the first superabsorbent material 226a are fixed to at least one of the lower sheet 221 and the intermediate sheet 223. Further, the particles of the second highly absorbent material 226b are fixed to at least one of the intermediate sheet 223 and the upper sheet 222. As described above, the first superabsorbent material 226 a and the second superabsorbent material 226 b are fixed to the material existence region 28. In each material existence region 28, the lower absorbent layer 227 is formed by the first superabsorbent material 226 a disposed between the lower sheet 221 and the intermediate sheet 223, and between the intermediate sheet 223 and the upper sheet 222. The upper absorbent layer 228 is formed by the second superabsorbent material 226b disposed.

  In the example of FIG. 5, the first superabsorbent material 226a and the second superabsorbent material 226b are of different types. In FIG. 5, the first superabsorbent material 226a and the second superabsorbent material 226b are provided with different parallel oblique lines (the same applies to FIG. 6 described later). The absorption rate of the first superabsorbent material 226a is greater than that of the second superabsorbent material 226b. That is, the absorption rate of the superabsorbent material constituting the lower absorbent layer 227 is larger than that of the superabsorbent material constituting the upper absorbent layer 228. The absorption rate in the present embodiment is a value based on the reciprocal of the time required for a predetermined amount of superabsorbent material to absorb a predetermined amount of liquid. As long as the absorption rate of the superabsorbent material constituting the lower absorbent layer 227 is maintained to be higher than that of the superabsorbent material constituting the upper absorbent layer 228, the lower absorbent layer 227 has the second superabsorbent. The absorbent material 226b may be included, and the upper absorbent layer 228 may include the first superabsorbent material 226a. In other words, the lower absorbent layer 227 includes at least the first superabsorbent material 226a, and the upper absorbent layer 228 includes at least the second superabsorbent material 226b. The absorbent core 22 may include three or more types of superabsorbent materials. A method for measuring the absorption rate will be described later.

  FIG. 6 is an enlarged view showing a cross section of the absorbent core 22a in the material existence region 28. As shown in FIG. The structure of the upper sheet 222 is the same as that of the upper sheet 222 in the absorbent core 22 of FIG. The structure of the intermediate sheet 223 is the same as that of the upper sheet 222, and the intermediate sheet 223 is a film formed by dispersing a plurality of water passage holes 26. In each of the upper sheet 222 and the intermediate sheet 223, the hole edge 261 of each water passage hole 26 projects toward the lower sheet 221. Further, in the hole edge portion 261, the size of the hole in the tip end portion 263 is smaller than that of the root portion 262. In the material presence region 28, the intermediate sheet 223 is bonded to the lower sheet 221 via the lower absorbent layer 227 and is bonded to the upper sheet 222 via the upper absorbent layer 228. In the example of FIG. 6, the diameter of the water passage hole 26 of the upper sheet 222 is the same as that of the intermediate sheet 223, but the diameter of the water passage hole 26 of the upper sheet 222 may be larger than that of the intermediate sheet 223. (The same applies to the area ratio of the water passage holes 26).

  In each material non-existence region 29 in FIG. 5, no superabsorbent material exists between the lower sheet 221 and the intermediate sheet 223 and between the intermediate sheet 223 and the upper sheet 222. Therefore, the lower sheet 221 and the intermediate sheet 223 are directly bonded, and the intermediate sheet 223 and the upper sheet 222 are directly bonded. The material non-existing region 29 may be a region containing a slightly superabsorbent material, and may be a low-density region as described above. In the material non-existence region 29, the lower sheet 221 and the intermediate sheet 223 are joined while the hole edge 261 is crushed, and the intermediate sheet 223 and the upper sheet 222 are joined.

  In the absorbent article 1, the upper sheet 222 is in contact with the top sheet 21, and the lower sheet 221 is in contact with the back sheet 23. That is, the upper sheet 222 is disposed closer to the wearer than the lower sheet 221. When excrement such as urine is excreted from the wearer of the absorbent article 1, the excrement liquid passes through the top sheet 21 and adheres to the wearer side surface of the upper sheet 222. On the surface of the upper sheet 222, in the material presence region 28, the liquid is guided to the upper absorbent layer 228 through the water passage holes 26 of the upper sheet 222 while diffusing in the longitudinal direction and the width direction. Further, in the material non-existing region 29 extending in the longitudinal direction, the liquid spreads in the width direction while diffusing in the longitudinal direction, and is guided to the upper absorption layer 228 in the material existing region 28.

  Since the absorption rate of the superabsorbent material (mainly the second superabsorbent material 226b) constituting the upper absorbent layer 228 is relatively small, most of the excreta liquid is not immediately absorbed by the upper absorbent layer 228, and the It penetrates further toward the sheet 223. The liquid reaches the wearer side surface of the intermediate sheet 223 and is guided to the lower absorbent layer 227 via the water passage holes 26 of the intermediate sheet 223 while diffusing in the longitudinal direction and the width direction. Since the absorption rate of the superabsorbent material (mainly the first superabsorbent material 226a) constituting the lower absorbent layer 227 is relatively high, the lower absorbent layer 227 absorbs the liquid in a short time. When a certain amount of liquid is absorbed by the superabsorbent material of the lower absorbent layer 227, the tip portion 263 of the water passage hole 26 in the intermediate sheet 223 is partially or entirely formed by the swollen superabsorbent material. Obstructed. Thereafter, the excrement liquid is gently absorbed by the superabsorbent material of the upper absorbent layer 228. In the absorbent core 22a, the highly absorbent materials of the lower absorbent layer 227 and the upper absorbent layer 228 are effectively used, so that the absorbent article 1 can receive a large amount of liquid.

  As described above, in the absorbent core 22a of FIG. 6, the upper absorbent layer 228 and the lower absorbent layer 227 are provided, and a plurality of water passage holes 26 are provided between the upper absorbent layer 228 and the lower absorbent layer 227. An intermediate sheet 223 is provided. In the intermediate sheet 223, the excrement liquid can be appropriately diffused, and most of the superabsorbent material in the lower absorbent layer 227 can be used effectively.

  Further, the absorption rate of the superabsorbent material in the lower absorbent layer 227 is larger than that of the superabsorbent material in the upper absorbent layer 228. In other words, the absorption speed of the upper absorption layer 228 is small. Thereby, the liquid can be more reliably guided to the lower absorption layer 227. In addition, the water-absorbing hole 26 of the intermediate sheet 223 is closed by swelling the superabsorbent material of the lower absorbent layer 227. Thereby, it can suppress that a liquid returns from the lower side absorption layer 227 to the upper side absorption layer 228. FIG. Further, the upper sheet 222 disposed closer to the wearer than the intermediate sheet 223 in the absorbent article 1 is also a film in which a plurality of water passage holes 26 are dispersed. As a result, the liquid can be appropriately diffused by both the intermediate sheet 223 and the upper sheet 222, and most of the superabsorbent material in the absorbent core 22a can be used more effectively.

  Here, a method for measuring the absorption rate of the superabsorbent material will be described. The absorption rate is measured by, for example, a measurement method (vortex method) based on JIS K7224. In this measurement method, 50 [g] deionized water or saline is used as a test solution, and the test solution and stirrer chip (the diameter at the center is 8 [mm], the diameter at both ends is 7 [mm], and the length is 30 mm. [Mm] and coated with fluororesin) is placed in a beaker, and the beaker is placed on a magnetic stirrer. The rotation speed of the magnetic stirrer is adjusted to 600 ± 60 times per minute, and it is confirmed that the test solution generates a stable vortex. In addition, after a sample of 0.50 [g] superabsorbent material (2.00 [g] when the test solution is a saline solution) is uniformly placed near the inner wall surface, a timer is started. The end point of the test is until the time when the stirrer chip is covered with the test liquid (for example, the time when the vortex disappears to become a flat liquid surface), and the time t is obtained as the time related to the absorption rate. The absorption rate is a value based on the reciprocal of the time t related to the absorption rate, and the shorter the time t related to the absorption rate, the larger the absorption rate.

  In the absorbent article 1, for example, the time t related to the absorption rate of the superabsorbent material constituting the upper absorbent layer 228 is 41 seconds or more, and the absorption rate of the superabsorbent material constituting the lower absorbent layer 227 is Such time t is 40 seconds or less. The time related to the absorption rate of the lower absorption layer 227 is preferably 0.95 times or less and more preferably 0.90 times or less of the time related to the absorption rate of the upper absorption layer 228.

  Various modifications are possible for the absorbent article 1 and the absorbent cores 22 and 22a.

  In the absorbent core 22 in FIG. 4, only the superabsorbent material 226 is provided between the lower sheet 221 and the upper sheet 222 except for the adhesive (the lower absorbent layer 227 and the upper absorbent layer in the absorbent core 22a). The same applies to 228.) A fiber material may be provided together with the superabsorbent material 226 between the lower sheet 221 and the upper sheet 222. In the example of FIG. 7, the superabsorbent material 226 and the fiber material 229 a are mixed between the lower sheet 221 and the upper sheet 222. The fiber material 229a is, for example, regenerated hydrophilic fibers such as cellulose, rayon, and cotton, synthetic fibers, and pulp fibers. It is preferable that the fiber material 229a is mixed at a ratio such that the superabsorbent material 226 can be regarded as a main material (for example, the weight ratio of the superabsorbent material 226 is 50% or more). In the example of FIG. 8, a thin fiber layer 229b is provided between the superabsorbent material 226 and the upper sheet 222, and the superabsorbent material 226 is indirectly bonded to the upper sheet 222 via the fiber layer 229b. Is done. Also in this case, the fiber layer 229b preferably has a basis weight that allows the superabsorbent material 226 to be regarded as a main material.

  In the absorbent core 22 a of FIG. 6, only one of the upper sheet 222 and the intermediate sheet 223 may be a film having the water passage holes 26, and the other may be a nonwoven fabric similar to the lower sheet 221. Further, depending on the design of the absorbent article 1 provided with the absorbent cores 22 and 22 a, the lower sheet 221 may be a film having the water passage holes 26. In this case, for example, the waste liquid that has reached the lower sheet 221 passes through the water passage hole 26 and is guided to the back sheet 23, and the liquid diffused on the back sheet 23 passes through the lower sheet 221. It returns to the superabsorbent material through the water holes 26. Thus, in the absorption cores 22 and 22a, at least one of the plurality of sheets sandwiching the superabsorbent material may be a film having the water passage holes 26. On the other hand, when the absorbent cores 22, 22 a are used in the absorbent article 1, the sheet having the water passage holes 26 is more on the wearer side than the lower sheet 221 in terms of rapidly diffusing the excrement liquid. It is preferable to arrange | position.

  The number and shape of the material existence regions 28 provided in the absorption cores 22 and 22a may be variously changed. The material non-existing region 29 may be other than a linear shape, and may, for example, continuously spread in a mesh shape along the longitudinal direction. In the absorption cores 22 and 22a, a plurality of material existence regions 28 are not necessarily provided, and only one material existence region 28 may be provided. Even in this case, by using a film formed by dispersing a plurality of water passage holes 26, the liquid of excreta can be appropriately diffused in the longitudinal direction and the width direction, and most of the superabsorbent material can be effectively used. It can be used.

  The absorbent article 1 and the absorbent cores 22 and 22a described above are not limited to a substantially rectangular shape, and may be, for example, a substantially hourglass shape in which the widths of both end portions in the longitudinal direction are larger than the width of the central portion. Further, the side sheet 3 may be omitted from the absorbent article 1.

  The above-described absorbent cores 22 and 22a may be used for absorbent articles other than the auxiliary absorbent pads, for example, pants-type or tape-type disposable diapers.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1 Absorbent article 21 Top sheet 22,22a Absorption core 23 Back sheet 26 Water passage hole 28 Material presence area 29 Material absence area 221 Lower sheet 222 Upper sheet 223 Intermediate sheets 226, 226a, 226b High absorbent material 227 Lower side Absorbent layer 228 Upper absorbent layer 261 Hole edge 262 Root portion 263 Tip

Claims (11)

A sheet member for absorbent articles,
A first sheet extending in the longitudinal direction;
A film formed by dispersing a plurality of water passage holes, a second sheet joined to the first sheet;
A superabsorbent material disposed between the first sheet and the second sheet and fixed to at least one of the first sheet and the second sheet;
A sheet member for absorbent articles, comprising: The absorbent article sheet member according to claim 1,
When the sheet member for absorbent articles is used in an absorbent article, the sheet member for absorbent articles is characterized in that the second sheet is disposed closer to the wearer than the first sheet. The sheet member for absorbent articles according to claim 1 or 2,
In the second sheet, a hole edge portion of each of the plurality of water passage holes protrudes toward the first sheet. The absorbent article sheet member according to claim 3,
In the hole edge portion, the size of the hole in the tip portion is smaller than that of the root portion. It is a sheet | seat member for absorbent articles as described in any one of Claims 1 thru | or 4, Comprising:
Between the 1st sheet and the 2nd sheet, the density of the superabsorbent material is low compared with the circumference, or the low density field where the superabsorbent material does not exist spreads along the longitudinal direction. The sheet | seat member for absorbent articles characterized by the above-mentioned. The sheet member for absorbent articles according to claim 3 or 4,
Between the first sheet and the second sheet, a density of the superabsorbent material is lower than the surrounding area, or a low density region where the superabsorbent material does not exist extends along the longitudinal direction. ,
The sheet member for absorbent articles, wherein the first sheet and the second sheet are joined in a state where the hole edge portion is crushed in the low density region. It is a sheet | seat member for absorbent articles as described in any one of Claim 1 thru | or 6, Comprising:
The sheet member for absorbent articles, wherein a diameter of the plurality of water passage holes is 0.1 mm or more and 3 mm or less. It is a sheet | seat member for absorbent articles as described in any one of Claim 1 thru | or 7, Comprising:
A third sheet joined to the second sheet on the opposite side of the first sheet;
Another superabsorbent material disposed between the second sheet and the third sheet and fixed to at least one of the second sheet and the third sheet;
A sheet member for absorbent articles, further comprising: The absorbent article sheet member according to claim 8,
When the sheet member for absorbent articles is used in an absorbent article, the third sheet is disposed closer to the wearer than the first sheet,
A lower absorbent layer is formed by the superabsorbent material disposed between the first sheet and the second sheet;
An upper absorbent layer is formed by the other highly absorbent material disposed between the second sheet and the third sheet,
The sheet member for absorbent articles, wherein an absorption rate of the superabsorbent material in the lower absorbent layer is larger than that of the other superabsorbent material in the upper absorbent layer. The absorbent article sheet member according to claim 8 or 9,
The sheet member for absorbent articles, wherein the third sheet is a film formed by dispersing a plurality of water passage holes. An absorbent article that receives excrement from a wearer,
The sheet member for absorbent articles according to any one of claims 1 to 10,
A top sheet that covers the main surface of the absorbent article sheet member on the wearer side;
A back sheet covering the other main surface of the sheet member for absorbent articles;
An absorbent article comprising:

Images