JP6826788B2 - Absorbent article - Google Patents

Description

The present invention relates to an absorbent article having excellent reversion prevention property.

Absorbent articles such as disposable diapers and sanitary napkins are required to have various absorption performances, and one of the typical ones is reversion performance. Reversion is a phenomenon in which urine once absorbed by the absorber returns to the surface of the article, and if it is easy to revert, there is a problem that the skin is unnecessarily soiled with excrement and skin troubles are likely to occur. Therefore, it is desired that the material does not easily go back. In particular, since reversion is likely to occur when the amount of absorption is large, the reversion prevention property is very important for products having a large amount of absorption, for example, products having an upper and lower two-layer structure.

However, as shown in FIG. 18, the absorber of the absorbent article is generally a mixture of pulp fibers and highly absorbent polymer particles and accumulated, and when such an absorber is absorbed, it is absorbed in the figure. As shown by the change in state, the more highly absorbent polymer particles located on the front side absorb and expand earlier, causing "gel blocking" in which the liquid permeability to the lower side decreases, and the liquid content such as urine is absorbed. It becomes difficult to penetrate the lower side. When such gel blocking occurs, the absorption on the upper side of the absorber is saturated even though there is an absorption capacity on the lower side of the absorber, and it becomes easy to revert. Needless to say, in FIG. 18, the size of the highly absorbent polymer particles is exaggerated in order to make it easier to understand the content ratio of the highly absorbent polymer particles and the change in absorption and expansion.

As a solution to such a problem, Patent Document 1 proposes to make the liquid permeability and water absorption rate of the highly absorbent polymer particles different between the upper layer absorber and the lower layer absorber, but there is room for improvement. is there.

Japanese Unexamined Patent Publication No. 10-118117 JP-A-2014-110890

Therefore, a main object of the present invention is to provide an absorbent article having excellent reversion prevention property.

The absorbent articles that have solved the above problems are as follows.
<First aspect>
In an absorbent article comprising at least a lower layer absorber, which is an aggregate of pulp fibers, and an upper layer absorber, which is provided on the front side thereof and is a mixed aggregate of pulp fibers and highly absorbent polymer particles.
The weight ratio of the highly absorbent polymer particles to the pulp fibers in the upper layer absorber is higher than the weight ratio of the highly absorbent polymer particles to the pulp fibers in the lower layer absorber.
At least in the middle portion in the width direction of the upper layer absorber, one slit extending in the front-rear direction or a plurality of slits extending in the width direction are provided at intervals.
An absorbent article characterized by that.

(Action effect)
In this absorber, the liquid content of excrement is also supplied to the upper layer absorber, but is preferentially supplied to the lower layer absorber through the slit. Here, since the weight ratio of the highly absorbent polymer particles to the pulp fibers in the lower layer absorber is lower than that of the upper layer absorber, gel blocking is less likely to occur than in the upper layer absorber, and the liquid content of excrement is higher in the lower layer absorber. Spreads over a wide area. Then, the liquid content absorbed by the lower layer absorber is absorbed by the upper layer absorber and transferred to the upper layer absorber so as to be sucked up by the upper layer absorber at least after the absorption saturation of the lower layer absorber, and is absorbed and retained by the upper layer absorber. At this time, the upper layer absorber has a high weight ratio of the highly absorbent polymer particles to the pulp fiber, can absorb and retain a larger amount of liquid, and the lower layer absorber preferentially absorbs, so that the front side (skin) of the absorber (skin). Absorption capacity will be left on the side) until the end. As a result, the absorbent article is further excellent in anti-return property.

<Second aspect>
In the upper layer absorber, the total weight of the pulp fibers and the highly absorbent polymer particles is 350 to 500 g / m ² , and the weight ratio of the highly absorbent polymer particles to the pulp fibers is 100 to 200%. The absorbent article of the first aspect, wherein the total grain of the pulp fibers and the highly absorbent polymer particles is 250 to 350 g / m ² , and the weight ratio of the highly absorbent polymer particles to the pulp fibers is 0 to 80%.

(Action effect)
The total weight of the pulp fibers and the highly absorbent polymer particles and the weight ratio of the highly absorbent polymer particles in the upper layer absorber and the lower layer absorber can be appropriately determined, but are preferably within the range of this embodiment.

<Third aspect>
The absorbent article according to claim 1 or 2, wherein the highly absorbent polymer particles contained in the upper layer absorber and the lower layer absorber have a water absorption rate of 35 to 60 seconds and a water absorption amount of 50 to 70 g / g.

(Action effect)
The properties of the highly absorbent polymer particles are not particularly limited, but are preferably within the range of this embodiment.

<Fourth aspect>
The absorbent article of any one of the first to third aspects, wherein the weight ratio of the highly absorbent polymer particles to the pulp fibers in the upper layer absorber increases stepwise or continuously as it approaches the slit.

(Action effect)
In the above-mentioned absorbent article, since the lower layer absorber preferentially absorbs due to the presence of the slit, the weight ratio of the highly absorbent polymer particles to the pulp fiber in the upper layer absorber is gradually or gradually as it approaches the slit. It is preferable to increase the absorption rate continuously at a portion close to the slit in the upper layer absorber to slow down the absorption rate.

<Fifth aspect>
The absorbent article of any one of the first to fourth aspects, wherein the weight ratio of the highly absorbent polymer particles to the pulp fibers in the lower layer absorber gradually or continuously decreases as it approaches the slit.

(Action effect)
In the above-mentioned absorbent article, the liquid content of excrement is supplied to the lower layer absorber through the slit. Therefore, as in this embodiment, the weight ratio of the highly absorbent polymer particles to the pulp fibers in the lower layer absorber is gradually or continuously lowered as it approaches the slit, and in the portion close to the slit in the lower layer absorber. It is preferable that the form is such that gel blocking is unlikely to occur.

<Sixth aspect>
Absorption according to any one of the first to fifth aspects, wherein a hydrophilic sheet having a density higher than that of the lower layer absorber is interposed between the upper layer absorber and the lower layer absorber at a position other than the slit. Sex goods.

(Action effect)
The upper layer absorber and the lower layer absorber may be brought into direct contact with each other without providing anything, but a hydrophilic sheet having a higher density than the lower layer absorber is provided at a position other than the slit as in this embodiment. This is preferable because the capillary phenomenon promotes the transfer of the liquid from the lower layer absorber to the upper layer absorber. If the hydrophilic sheet closes the slit, the supply of the liquid to the lower layer absorber is hindered, which is not preferable.

<7th aspect>
The superabsorbent polymer particles contained in the lower layer absorbent body is absorption water rate from 20 to 35 seconds and absorption water weight 50 to 70 g / g, the superabsorbent polymer particles contained in the upper layer absorbent body absorption water rate There weight 60-80 seconds and absorption water is 50 to 70 g / g, the absorbent article of any one aspect of the first, second, and 4-6.

(Action effect)
The characteristics of the highly absorbent polymer particles in each layer are not particularly limited, but as in this embodiment, the highly absorbent polymer particles contained in the lower layer absorber are preferably those having excellent liquid permeability, and the highly absorbent polymer particles contained in the upper layer absorber are highly absorbent. The sex polymer particles preferably have a large absorption amount.

According to the present invention, there are advantages such as an absorbent article having excellent reversion prevention property.

It is a plan view (inner surface side) of the pants type disposable diaper in the unfolded state. It is a plan view (outer surface side) of the pants type disposable diaper in the unfolded state. It is a top view of the absorber. FIG. 5 is a sectional view taken along the line CC of FIG. FIG. 1 is a sectional view taken along the line AA of FIG. It is BB sectional view of FIG. It is a perspective view of the wearing state of a pants type disposable diaper. It is a plan view (outer surface side) of the pants type disposable diaper in the unfolded state. It is sectional drawing corresponding to the AA cross section of FIG. It is a top view of the absorber. It is sectional drawing which shows schematic the sectional structure of the absorber. It is sectional drawing which shows schematic the sectional structure of the absorber. It is sectional drawing which shows schematic the sectional structure of the absorber. It is sectional drawing which shows schematic the sectional structure of the absorber. It is sectional drawing which shows schematic the sectional structure of the absorber. It is sectional drawing which shows schematic the sectional structure of the absorber. It is a top view of the absorber. It is sectional drawing which shows schematic the sectional structure of the absorber.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The dotted pattern portion in the figure indicates a joining means such as a hot melt adhesive.
1 to 7 show pants-type disposable diapers. This pants-type disposable diaper (hereinafter, also simply referred to as a diaper) has an outer body 20 that integrally forms a front body F and a back body B, and an inner surface of the outer body 20 that extends from the front body F to the back body B. It has a fixed interior body 10, and the interior body 10 is formed by interposing absorbers 18 and 19 between the liquid-permeable top sheet 11 and the liquid-impermeable sheet 12. In manufacturing, the back surface of the interior body 10 is joined to the inner surface (upper surface) of the exterior body 20 by a joining means such as a hot melt adhesive (dot pattern portion in FIG. 2), and then the interior body 10 and the exterior body 20 are joined. Is folded at the center in the front-rear direction (longitudinal direction), which is the boundary between the front body F and the back body B, and both side portions thereof are joined to each other by heat welding or hot melt adhesive to form the side seal portion 21. This results in a pants-type disposable diaper with a waist opening and a pair of left and right leg openings.

(Example of interior structure)
As shown in FIGS. 4 to 6, the interior body 10 has a structure in which absorbers 18 and 19 are interposed between the liquid-permeable top sheet 11 and the liquid-impermeable sheet 12, and the top is formed. The excrement liquid that has passed through the sheet 11 is absorbed and held by the absorbers 18 and 19. The planar shape of the interior body 10 is not particularly limited, but it is generally substantially rectangular as shown in the illustrated form.

As the liquid-permeable top sheet 11 that covers the front side (skin contact surface side) of the absorbers 18 and 19, a perforated or non-perforated non-woven fabric, a porous plastic sheet, or the like is preferably used. The material fibers constituting the non-woven fabric can be olefin-based fibers such as polyethylene or polypropylene, synthetic fibers such as polyester-based and polyamide-based, recycled fibers such as rayon and cupra, and natural fibers such as cotton. , A non-woven fabric obtained by an appropriate processing method such as a spun bond method, a thermal bond method, a melt blown method, or a needle punch method can be used. Among these processing methods, the spunlace method is excellent in that it is rich in flexibility and drapeability, and the thermal bond method is excellent in that it is bulky and soft. When a large number of through holes are formed in the liquid permeable top sheet 11, urine or the like is rapidly absorbed. In the illustrated form, the liquid permeable top sheet 11 wraps around the side edges of the absorbers 18 and 19 and extends to the back side of the absorbers 18 and 19.

A liquid-impermeable plastic sheet such as polyethylene or polypropylene is used as the liquid-impermeable sheet 12 that covers the back side (non-skin contact surface side) of the absorbers 18 and 19, but in recent years, it is moisture-permeable from the viewpoint of preventing stuffiness. Those having the above are preferably used. The water-impervious / moisture-permeable sheet can be obtained by melting and kneading inorganic fine particles such as calcium carbonate in an olefin resin such as polyethylene or polypropylene to form a sheet, and then stretching the sheet in the uniaxial or biaxial direction. A microporous sheet can be preferably used. In the illustrated form, the liquid-impermeable sheet 12 is folded back on both sides of the absorbers 18 and 19 in the width direction together with the liquid-permeable top sheet 11, but is not limited to such a structure and is not limited to other known structures. The structure can be adopted.

Three-dimensional gather BSs that fit around the legs are formed on both sides of the interior body 10. As shown in FIGS. 5 and 6, the three-dimensional gather BS has a fixed portion fixed to the side portion of the back surface of the interior body 10, and the side surface of the interior body from the fixed portion via the side of the interior body. The main body extending to the portion, the inverted portion formed by fixing the front and rear ends of the main body to the side portion of the surface of the interior body in the inverted state, and the portion of the inverted portion formed as non-fixed. The free portion is formed by a three-dimensional gather sheet 15 which is made into a double sheet by folding back, and an elongated three-dimensional gather elastic member 16 is arranged at the tip of the free portion or the like between the double sheets. There is. With such a structure, in the three-dimensional gather BS, the free portion protruding from the side edge portion of the absorber due to the contraction of the three-dimensional gather elastic member 16 rises in the product state as shown by the alternate long and short dash line in FIG. .. As the three-dimensional gather sheet 15, a non-woven fabric having water repellency is preferably used.

As the gather elastic member 16, commonly used materials such as styrene rubber, olefin rubber, urethane rubber, ester rubber, polyurethane, polyethylene, polystyrene, styrene butadiene, silicone, and polyester can be used. Further, in order to make it difficult to see from the outside, it is preferable to arrange the thickness at 925 dtex or less, the tension at 150 to 350%, and the interval at 7.0 mm or less. As the gather elastic member 16, a tape-shaped member having a certain width can be used in addition to the thread-shaped member as shown in the illustrated figure.

Similar to the liquid-permeable top sheet 11, the material fibers constituting the above-mentioned three-dimensional gather sheet 15 include olefin-based fibers such as polyethylene and polypropylene, polyester-based and amide-based synthetic fibers, and recycled fibers such as rayon and cupra. It can be a natural fiber such as cotton, and a non-woven fabric obtained by an appropriate processing method such as a spun bond method, a thermal bond method, a melt blown method, or a needle punch method can be used, but in particular to prevent stuffiness. It is advisable to use a non-woven fabric that suppresses the basis weight and has excellent breathability. Further, the three-dimensional gather sheet 15 is a silicone-based, paraffin metal-based, or alkylchromic chloride-based water repellent agent in order to prevent the permeation of urine and the like, prevent fogging, and enhance the feel (dry feeling) to the skin. It is desirable to use a water-repellent treated non-woven fabric coated with.

(Structural example of exterior body)
As shown in FIGS. 4 to 6, the exterior body 20 has a two-layer structure composed of a pressing sheet 20A made of a non-woven fabric or the like and a back sheet 20B, respectively, and is formed between the pressing sheet 20A and the back sheet 20B and the back. An elastic member is arranged between the non-woven fabrics of the folded portion 20C formed by folding the sheet 20B to the inner surface side at the waist opening edge, and the outer body 20 contracts due to the contraction force of the elastic member in the natural length state, whereby the outer body 20 is formed. Elasticity is given. The planar shape is substantially an hourglass shape as a whole due to the concave leg circumference lines 29 formed to form leg openings on both sides of the middle.

In the exterior body 20 of the illustrated form, as elastic members, in the developed shape shown in FIGS. 1 to 3, the waist elastic member 24 arranged near the waist opening 23, and the front body F and the back body B are vertically formed. It has a plurality of lower waist elastic members 25 arranged along the width direction at intervals in the direction, and in each of the front body F and the rear body B, separately from the waist lower elastic member group 25, one of them. From the side seal portion 21 of the head toward the crotch portion along one leg opening, crossing the crotch portion, and extending along the other leg opening while curving in a pattern extending to the other side seal portion 21. It includes a plurality of curved elastic members 26, 28 arranged at intervals without intersecting each other. Each of these elastic members 24 to 28 is fixed in a state of being stretched at a predetermined stretching rate along the extending direction thereof. The exterior body 20 is not provided with a so-called leg-surrounding elastic member that is continuous from the side seal portion of the front body F to the side seal portion of the rear body B along the leg circumference line 29.

The waist elastic member 24 is made of a plurality of rubber threads or the like arranged at intervals in the vertical direction in the vicinity of the waist opening edge within the range of the side seal portion 21 in which the front body F and the back body B are joined. It is an elongated elastic member, and is for attaching a diaper to the body by applying an elastic force so as to tighten the circumference of the body. Although thread rubber is used for the waist elastic member 24 in the illustrated example, for example, a tape-shaped elastic member may be used. Further, although the waist elastic member 24 of the illustrated embodiment is sandwiched between the non-woven fabrics of the folded portion 20C of the back sheet 20B at the waist, it may be sandwiched between the pressing sheet 20A and the back sheet 20B.

The waist lower elastic member 25 is an elongated elastic member such as a rubber thread arranged at intervals in the vertical direction over a range from the upper part to the lower part of the side seal portion 21, and is formed on the front body F and the rear. The purpose is to apply elastic force in the width direction to the waist circumference of the body B so that the diaper is brought into close contact with the body. The boundary between the waist elastic member 24 and the waist lower elastic member 25 does not necessarily have to be clear. For example, among the elastic members arranged in the width direction at intervals in the vertical direction on the front body F and the back body B, some of the elastic members on the upper side function as waist elastic members even if the number cannot be specified. , The remaining elastic member may function as the elastic member in the lower part of the waist.

In the back body B, the dorsal curved elastic member 26 arranged separately from the waist lower elastic member 25 is an elongated elastic member such as rubber thread, and is arranged along a predetermined curve. The dorsal curved elastic member 26 may be one, but is preferably a plurality, and in the illustrated example, it is an elongated elastic member such as four rubber threads, and these dorsal curved elastic members 26 are mutually exclusive. They are arranged at intervals without intersecting. The dorsal curved elastic member group 26 is not substantially arranged as a bundle with a few elastic members closely spaced, but is 3 to 20 mm so as to form a predetermined expansion / contraction zone. Three or more, preferably four or more, are arranged at an interval of preferably about 6 to 16 mm.

In the front body F of the exterior body 20, the ventral curved elastic member 28 disposed separately from the waist lower elastic member group 25 is an elongated elastic member such as rubber thread, and is arranged along a predetermined curve. There is. The ventral curved elastic member 28 may be one, but is preferably a plurality, and in the illustrated example, there are four filamentous elastic members, and these ventral curved elastic members 28 do not intersect with each other. , Are arranged at intervals. The ventral curved elastic member group 28 is also not arranged as a bundle with a few elastic members closely spaced, but is 3 to 20 mm so as to form a predetermined expansion / contraction zone. Three or more, preferably four or more, are arranged at an interval of preferably about 6 to 16 mm.

As shown in FIG. 2, the waist lower elastic members 25 and the curved elastic members 26 and 28 arranged on the front body F and the rear body B are continuously fixed to the exterior body 20 at the time of manufacturing, and then The middle part in the width direction (the part surrounded by the alternate long and short dash line in the figure) of the part overlapping the absorbers 18 and 19 is finely cut with a predetermined cutting pattern to form a non-shrinkable part on which no contraction force acts. The portion extending laterally from the portion can be a contraction portion on which a contraction force acts (that is, a portion in which the lower waist elastic member 25 and the curved elastic members 26 and 28 are continuously left). This makes it possible to prevent unnecessary shrinkage of the interior body (particularly the absorbers 18 and 19) in the width direction. Of course, as shown in FIG. 8, the waist lower elastic members 25 and the curved elastic members 26 and 28 can be continuously arranged across the interior body 10.

The exterior body 20 described above can be manufactured by, for example, the techniques described in JP-A-4-28363 and JP-A-11-332913. Further, in order to cut the curved elastic members 26 and 28 on the interior body 10 to make them discontinuous, it is described in JP-A-2002-35029, JP-A-2002-178428 and JP-A-2002-273808. The cutting method is preferably adopted.

Unlike the illustrated example, the curved elastic members 26 and 28 may be provided only on either the front body F or the back body B. Further, when the curved elastic members 26 and 28 are provided on both the front body F and the rear body B, a part or all of the group of the curved elastic members 28 arranged on the front body F side and the rear body B side are arranged. A form (not shown) in which a part or all of the group of the curved elastic members 26 intersects with each other can be adopted, but as shown in the illustrated example, the group of the curved elastic members 28 arranged on the front body F side and the group of the curved elastic members 28 It is preferable that the group of the curved elastic members 26 arranged on the back body B side is separated from each other in the vertical direction at a position slightly biased toward the front and rear intermediate portions, particularly the front body F, without intersecting with each other.

Further, the curved elastic members 26 and 28 do not have to be curved as a whole, and may have a partially linear portion.

The elongation rate of the elastic members 24 to 28 at the time of fixing can be appropriately determined, but in the case of a normal adult, the waist elastic member 24 is about 160 to 320%, and the waist lower elastic member 25 is about 160 to 320%. , The curved elastic members 26 and 28 can be about 230 to 320%.

(Front and rear presser sheet)
As shown in FIGS. 1 and 4, the front and rear presser sheets are used to cover the front and rear ends of the interior body 10 mounted on the inner surface of the exterior body 20 and to prevent leakage from the front and rear edges of the interior body 10. 50 and 60 may be provided. Explaining the illustrated form in more detail, the front presser sheet 50 extends over the entire width direction from the inner surface of the folded portion 20C of the waist side end portion of the inner surface of the front body F to the position where it overlaps with the front end portion of the interior body 10. The rear presser sheet 60 extends over the entire width direction from the inner surface of the folded-back portion 20C at the waist side end portion of the inner surface of the rear body B to a position overlapping the rear end portion of the interior body 10. If a slight non-adhesive part is provided on the inseam side edges of the front and rear presser sheets 50 and 60 over the entire width direction (only the central part may be used), not only the adhesive does not squeeze out, but also this part is slightly separated from the top sheet. It can be floated and function as a leak-proof wall.

As shown in the illustrated form, if the front and rear pressing sheets 50 and 60 are attached as separate bodies, there is an advantage that the degree of freedom in material selection is increased, but there is also a demerit such as an increase in materials and manufacturing processes. Therefore, the folded portion 20C formed by folding the outer body 20 onto the inner surface of the diaper can be extended to a portion overlapping the inner body 10 to form a portion equivalent to the above-mentioned pressing sheets 50 and 60.

(About absorber)
The absorbers 18 and 19 have a two-layer structure as shown in FIGS. 3 to 6 and 11. The lower layer absorber 18 is an aggregate composed of at least pulp fibers 18f, preferably a mixed accumulation of pulp fibers and 18f and highly absorbent polymer particles 18p. On the other hand, the upper layer absorber 19 is a mixed accumulation of pulp fibers 19f and highly absorbent polymer particles 19p. These absorbers 18 and 19 can be wrapped with a wrapping sheet 14 having liquid permeability and liquid retention, such as crepe paper, if necessary, in order to retain the shape and polymer.

As the highly absorbent polymer particles 18p and 19p contained in the upper layer absorber 19 and the lower layer absorber 18, those used for this kind of absorbent article can be used as they are, for example, a standard sieve of 500 μm (JIS Z8801-1). It is desirable that the proportion of particles remaining on the sieve is 30% by weight or less after sieving using (2006) (shaking for 5 minutes), and sieving using a standard sieve of 180 μm (JIS Z8801-1: 2006). It is desirable that the proportion of particles remaining on the sieve after (shaking for 5 minutes) is 60% by weight or more.

The highly absorbent polymer particles 18p and 19p are not particularly limited, but those having a water absorption rate of 35 to 60 seconds and a water absorption amount of 50 to 70 g / g can be preferably used. Highly absorbent polymer particles 18p and 19p include starch-based, cellulosic-based and synthetic polymer-based ones, such as starch-acrylic acid (salt) graft copolymer, starch-acrylonitrile copolymer saponified product, and sodium carboxy. A crosslinked product of methyl cellulose or an acrylic acid (salt) polymer can be used. The basis weight of the highly absorbent polymer particles 18p and 19p can be appropriately determined according to the absorption amount required for the product. Therefore, although it cannot be said unconditionally, the total amount of the absorbers 18 and 19 can be 100 to 350 g / m ² .

The shapes of the lower layer absorber 18 and the upper layer absorber 19 can be appropriately determined and may be rectangular, respectively, but it is preferable that the crotch portion has a constricted portion 13 narrower than both the front and rear sides thereof. .. The dimensions of the constricted portion 13 of the lower layer absorber 18 and the upper layer absorber 19 can be appropriately determined, but the width 13w of the narrowest portion thereof can be about 40 to 60% of the total width of each. In the case of having such a constricted portion 13, if the planar shape of the interior body 10 is substantially rectangular, the absorbers 18 and 19 are located in the portions corresponding to the constricted portions 13 of the absorbers 18 and 19 in the interior body 10. A remainder portion is formed that does not have. The upper layer absorber 19 may have the same dimensions as the lower layer absorber 18, but it is desirable that the overall length 19L and the overall width 19W of the upper layer absorber 19 are shorter than those of the lower layer absorber 18 as shown in the figure. In a normal case, the total length 19L of the upper layer absorber 19 can be about 60 to 90% of the total length 18L of the lower layer absorber 18, and the total width 19W of the upper layer absorber 19 is 60 to 90 of the total width 18W of the lower layer absorber 18. It can be about%.

Characteristically, as shown in FIG. 3 and the like, one slit 17 extending in the front-rear direction is provided at the center of the upper layer absorber 19 in the width direction. The slit 17 is a portion that penetrates in the thickness direction of a predetermined width, and as shown in FIGS. 9, 10 and 12, even if both the upper layer absorber 19 and the lower layer absorber 18 are provided so as to penetrate in the thickness direction. good. Further, as shown in FIG. 17B, a plurality of slits 17 may be provided at intervals in the width direction.

The width 17d of the slit 17 is not particularly limited, but it is preferably 5 to 20% of the total width 19w of the upper layer absorber 19. Further, the length 17L of the slit 17 in the front-rear direction can be appropriately determined, and can be, for example, about 30 to 70% of the total length 19L of the upper layer absorber 19. The position of the slit 17 in the front-rear direction is not particularly limited, but it is desirable to provide the slit 17 so that at least a part of the slit 17 is located in the crotch portion, and more specifically, the slit 17 is located in the constricted portion 13 of the absorbers 18 and 19. As shown in the illustrated embodiment, when the upper layer absorber 19 extends widely behind the crotch portion, the rear end portion 17e of the slit 17 is branched into a plurality of Y-shaped portions as shown in FIG. 17A. Is also a preferred form.

Further, as shown in FIGS. 11 and 12, the weight ratio of the highly absorbent polymer particles 19p to the pulp fibers 19f in the upper layer absorber 19 is the weight ratio of the highly absorbent polymer particles 18p to the pulp fibers 18f in the lower layer absorber 18. Is considered to be higher than. Needless to say, in addition to FIGS. 11 and 12, in FIGS. 13 to 16, in order to make it easy to understand the content ratio of the highly absorbent polymer particles 18p and 19p and the change in absorption and expansion, the highly absorbent polymer particles The sizes of 18p and 19p are exaggerated.

The weight ratio of the highly absorbent polymer particles 19p and 18p to the pulp fibers 19f and 18f in the upper layer absorber 19 and the lower layer absorber 18 can be appropriately determined, but the total weight of the upper layer absorber 19 (pulp 19f and the highly absorbent polymer) can be determined. When the total of the particles 19p) is 350 to 500 g / m ² , the weight ratio of the highly absorbent polymer particles 19p to the pulp fibers 19f in the upper layer absorber 19 may be about 100 to 200%, particularly 150 to 200%. preferable. Further, when the total texture of the lower layer absorber 18 (the total of the pulp 18f and the highly absorbent polymer particles 18p) is 250 to 350 g / m ² , the weight of the highly absorbent polymer particles 18p with respect to the pulp fibers 18f in the lower layer absorber 18 The ratio is preferably about 0 to 80%, particularly preferably 30 to 70%.

In the absorbers 18 and 19 configured as described above, the liquid L of excrement is also supplied to the upper layer absorber 19 as shown in FIGS. 11 and 12, respectively, but more than that. Is preferentially supplied to the lower layer absorber 18 through the slit 17. Here, since the weight ratio of the highly absorbent polymer particles 18p to the pulp fiber 18f in the lower layer absorber 18 is lower than that of the upper layer absorber 19, gel blocking is less likely to occur than in the upper layer absorber 19, and the liquid content of excrement is reduced. It diffuses more extensively within the lower absorber 18. In the figure, the movement of the liquid is indicated by an arrow. Then, the liquid content absorbed by the lower layer absorber 18 is transferred to the upper layer absorber 19 so as to be sucked up by the upper layer absorber 19 at least after the absorption saturation of the lower layer absorber 18, and becomes into the upper layer absorber 19. Absorbed and retained. At this time, the upper layer absorber 19 has a high weight ratio of the highly absorbent polymer particles 19p to the pulp fiber 19f, can absorb and retain a larger amount of liquid, and the lower layer absorber 18 preferentially absorbs the absorber. Absorption capacity is left on the front side (skin side) of 18 and 19 until the end. As a result, the absorbent article is further excellent in anti-return property.

In view of such absorbing mechanism, as the superabsorbent polymer particles 18p contained in the lower layer absorbent body 18 is excellent in liquid permeability, specifically 20 to 35 seconds and absorption water weight absorption water rate in the 50~70g / preferably has a g, those high-absorbent polymer particles 19p absorption amount contained in the upper layer absorbent body 19 is large, the amount of 60 to 80 seconds and absorption water absorption water rate in particular is 50 to 70 g / g Is preferable.

Further, since the above-mentioned absorption mechanism is based on the fact that the lower layer absorber 18 preferentially absorbs due to the presence of the slit 17, as shown in FIG. 13, the upper layer absorber 19 has a higher height than the pulp fiber 19f. The weight ratio of the absorbent polymer particles 19p is increased stepwise or continuously as it approaches the slit 17, and the absorption rate of the highly absorbent polymer particles 19p is slower than that of the pulp fiber 19f. It is one preferable form to slow down the absorption rate at the portion of the upper layer absorber 19 near the slit 17.

Further, since the above-mentioned absorption mechanism is basically that the liquid content of excrement is supplied to the lower layer absorber 18 through the slit 17, as shown in FIG. 14, the lower layer absorber The weight ratio of the highly absorbent polymer particles 18p to the pulp fiber 18f in 18 is gradually or continuously lowered as it approaches the slit 17, and gel blocking occurs at a portion of the lower absorber 18 near the slit 17. It is preferable to have a difficult form.

By combining these forms, as shown in FIG. 15, in the upper layer absorber 19, the weight ratio of the highly absorbent polymer particles 19p to the pulp fiber 19f is gradually or continuously increased as it approaches the slit 17, and the lower layer is formed. In the absorber 18, it is also possible to make the weight ratio of the highly absorbent polymer particles 18p to the pulp fibers 18f gradually or continuously decrease as it approaches the slit 17.

On the other hand, the upper layer absorber 19 and the lower layer absorber 18 may be brought into direct contact with each other without providing anything, but as shown in FIG. 16, the density is higher than that of the lower layer absorber 18 at positions other than the slit 17. It is preferable to provide a highly hydrophilic sheet 30. As the hydrophilic sheet 30, crepe paper or a non-woven fabric coated with a hydrophilic agent can be preferably used. As a result, the transfer of the liquid from the lower layer absorber 18 to the upper layer absorber 19 is promoted by the capillary phenomenon. If the hydrophilic sheet 30 blocks the slit 17, the supply of the liquid to the lower layer absorber 18 is hindered, which is not preferable.

<Explanation of terms in the specification>
When the following terms are used in the specification, they have the following meanings unless otherwise specified in the specification.
-The "front-back (vertical) direction" means the direction connecting the ventral side (front side) and the dorsal side (rear side), and the "width direction" means the direction orthogonal to the front-back direction (horizontal direction).
-"Unfolded state" means a state in which the unfolded state is flat without shrinkage or slack.
-"Elongation rate" means a value when the natural length is 100%.
・ "Metsuke" is measured as follows. After pre-drying the sample or test piece, leave it in a test room or device in a standard state (the test place is a temperature of 20 ± 5 ° C. and a relative humidity of 65% or less) to bring it into a constant weight state. Pre-drying refers to making a sample or test piece constant in an environment where the relative humidity is 10 to 25% and the temperature does not exceed 50 ° C. It is not necessary to pre-dry the fibers having an official moisture content of 0.0%. A sample having a size of 200 mm × 250 mm (± 2 mm) is cut out from the test piece in a constant weight state using a paper density plate (200 mm × 250 mm, ± 2 mm). The weight of the sample is measured, the weight per square meter is calculated, and the basis weight is used.
-The "thickness" is automatically measured using an automatic thickness measuring device (KES-G5 handy compression tester) under the conditions of a load of 0.098 N / cm ² and a pressurized area of 2 cm ² .
-The "water absorption amount" is measured by JIS K7223-1996 "Water absorption amount test method for highly water-absorbent resin".
-"Water absorption rate" is the "time to the end point" when JIS K7224-1996 "Water absorption rate test method for highly water-absorbent resin" was performed using 2 g of highly absorbent polymer and 50 g of physiological saline. And.
-If there is no description about the environmental conditions in the test or measurement, the test or measurement shall be performed in a test room or equipment under standard conditions (test location: temperature 20 ± 5 ° C, relative humidity 65% or less). ..
-Unless otherwise specified, the dimensions of each part mean the dimensions in the unfolded state, not in the natural length state.

The present invention can be used for all absorbent articles such as pants-type disposable diapers as in the above example, various disposable diapers such as tape type and pad type, and sanitary napkins.

10 ... Interior body, 11 ... Top sheet, 12 ... Liquid permeable sheet, 13 ... Constricted part, 14 ... Packaging sheet, 15 ... Three-dimensional gathered sheet, 16 ... Three-dimensional gathered elastic member, 17 ... Slit, 18, 19 ... Absorption Body, 18 ... Lower layer absorber, 19 ... Upper layer absorber, 18p, 19p ... Highly absorbent polymer particles, 18f, 19f ... Pulp fiber, 20 ... Exterior body, 20C ... Folded part, 21 ... Side seal part, 24 ... Waist Part elastic member, 25 ... Lower waist elastic member, 26, 28 ... Curved elastic member, 26 ... Dorsal curved elastic member, 28 ... Ventral curved elastic member, 29 ... Leg circumference line, B ... Back body, BS ... Solid Gather, F ... front body, 30 ... hydrophilic sheet.

Claims (5)

Absorbency provided with a lower layer absorber, which is a mixed accumulation of pulp fibers and highly absorbent polymer particles, and an upper layer absorber, which is a mixed and accumulated product of pulp fibers and highly absorbent polymer particles, provided on the front side thereof. In the article
In the upper layer absorber, the total weight of the pulp fibers and the highly absorbent polymer particles is 350 to 500 g / m ² , and the weight ratio of the highly absorbent polymer particles to the pulp fibers is 150 to 200%.
In the lower layer absorber, the total weight of the pulp fibers and the highly absorbent polymer particles is 250 to 350 g / m ² , and the weight ratio of the highly absorbent polymer particles to the pulp fibers is 30 to 70%.
At least in the middle portion in the width direction of the upper layer absorber, one slit extending in the front-rear direction or a plurality of slits extending in the width direction are provided at intervals in the width direction.
The entire back side of the lower layer absorber is continuously covered with a liquid-impermeable sheet.
There is no means for discharging the liquid content of excrement supplied to the upper layer absorber and the lower layer absorber to the outside of the absorbent article.
The highly absorbent polymer particles contained in the lower layer absorber have a water absorption rate of 20 to 35 seconds and a water absorption amount of 50 to 70 g / g, and the highly absorbent polymer particles contained in the upper layer absorber have a water absorption rate of 60 to 60 to. 80 seconds and water absorption of 50-70 g / g,
An absorbent article characterized by that. The absorbability according to claim 1, wherein the width of the slit is 5 to 20% of the total width of the upper layer absorber, and the length of the slit in the front-rear direction is 30 to 70% of the total length of the upper layer absorber. Goods. The absorbent article according to claim 1 or 2 , wherein the weight ratio of the highly absorbent polymer particles to the pulp fibers in the upper layer absorber increases stepwise or continuously as it approaches the slit. The absorbent article according to any one of claims 1 to 3 , wherein the weight ratio of the highly absorbent polymer particles to the pulp fibers in the lower layer absorber decreases stepwise or continuously as it approaches the slit. The invention according to any one of claims 1 to 4 , wherein a hydrophilic sheet having a density higher than that of the lower layer absorber is interposed between the upper layer absorber and the lower layer absorber at a position other than the slit. Absorbent article.

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