JP6756213B2 - Absorbents and absorbent articles - Google Patents

Description

The present invention relates to an absorber that is attached to the inseam of the wearer to absorb and retain a liquid such as urine, and an absorbent article provided with the absorber.

Conventionally, an absorbent article worn on the inseam of a wearer has been known for the purpose of absorbing and retaining excreted body fluid. Examples of absorbent articles are disposable diapers, urine pads, and sanitary napkins. Disposable diapers include, for example, pants-type diapers in which the left and right sides of the front and back bodies are joined, and tape-type diapers that are worn by attaching a fastening tape attached to the back body to the front body. Things are known. Such an absorbent article generally includes an absorber for absorbing and holding a body fluid such as urine between a liquid-permeable top sheet and a liquid-impermeable back sheet. This absorber is mainly composed of an absorbent core in which fluff pulp and a particulate superabsorbent polymer (SAP) are mixed, and a core wrap sheet such as a tissue that wraps the absorbent core.

Further, conventionally, in an absorbent article having the above configuration, a technique of pressing from the skin facing surface and / or the skin non-facing surface side of the absorber and applying it to the core wrap sheet and the absorbent core to form a squeezing groove Is known (for example, Patent Document 1). By forming the squeeze groove in the absorber in this way, the body fluid in contact with the absorber flows along the squeeze groove, so that the body fluid can be quickly diffused over a wide range. In addition, by forming a squeeze groove in the absorber, its flexural rigidity is increased and shape retention is maintained, so that the absorber can be prevented from being crushed even when worn.

Japanese Unexamined Patent Publication No. 2012-143535

By the way, when the squeezing groove is formed over the core wrap sheet and the absorbent core as described above, the shape of the core wrap sheet is restored with the passage of time. As a result, it was found that there is a problem that the core wrap sheet and the absorbent core are peeled off and a gap (float) is generated between them. In order to quickly transfer the body fluid from the core wrap sheet to the absorbent core, it is important that the fluff pulp and the absorbent polymer constituting the absorbent core adsorb the body fluid held on the core wrap sheet. However, if there is a gap between the core wrap sheet and the absorbent core as described above, the adsorption effect of the body fluid by the absorbent core is not effectively exhibited, and the body fluid from the core wrap sheet to the absorbent core is transferred. The transition is hindered. If this happens, body fluid will remain on the core wrap sheet, resulting in a damp feel to the wearer, which may lead to discomfort when worn.

Therefore, an object of the present invention is to suppress peeling between the core wrap sheet and the absorbent core, at least in the absorbent article in which the core wrap sheet and the absorbent core have squeezed grooves.

As a result of diligent studies on means for solving the above problems, the inventor of the present invention found an absorbent polymer in the absorbent core in a region near the squeeze groove formed between the core wrap sheet and the absorbent core. We decided to distribute a lot. As a result, when the squeeze groove is formed, the constituent fibers of the core wrap sheet are likely to bite into the gaps of the absorbent polymer in the absorbent core, and the bonding strength between the core wrap sheet and the absorbent core can be increased. Then, the present inventor has come up with the idea that the problems of the prior art can be solved based on the above findings, and has completed the present invention. More specifically, the present invention has the following configurations.

The present invention relates to an absorber that is attached to the inseam of the wearer to absorb and retain a liquid such as urine, and an absorbent article such as a disposable diaper provided with the absorber. The absorber 30 according to the present invention has an absorbent core 31 and a core wrap sheet 32. The absorbent core 31 has at least a granular absorbent polymer 31b. The core wrap sheet 32 covers at least one of the skin-facing surface and the skin-non-facing surface of the absorbent core 31. The core wrap sheet 32 preferably covers the skin-facing surface, the skin-non-facing surface, and the side surface of the absorbent core 31. In the absorbent article of the present invention, one or more linear pressing grooves 40 are formed in the thickness direction at least over the core wrap sheet 32 and the absorbent core 31. The absorbent article according to the present invention includes a liquid-permeable top sheet 10, a liquid-impermeable back sheet 20, and the absorbent body 30 according to the present invention arranged between the top sheet 10 and the back sheet 20. And. The squeeze groove 40 may be formed over the top sheet 10, the core wrap sheet 32, and the absorbent core 31.
Here, the absorbent core 31 has a composition of at least 100 parts by mass of the absorbent core in a thickness range within 10% from the skin surface of the absorbent core with respect to the thickness of the entire absorbent core 31. In some cases, the absorbent polymer is 50 parts by mass or more.

As in the above configuration, the thickness range of 10% from the surface of the absorbent core 31 on the side where the squeeze groove 40 of the absorbent core 31 is formed (at least one side when formed on both sides). When the core wrap sheet 32 and the absorbent core 31 are simultaneously pressed from either or both of the skin facing surface side and the skin non-facing surface side to form the squeezing groove 40 by arranging the absorbent polymer at a high density. , The constituent fibers of the core wrap sheet 32 will firmly bite between the absorbent polymers 31b in the absorbent core 31. In this way, by exerting the anchor effect of connecting the core wrap sheet 32 to the absorbent core 31, the bonding strength between the absorbent core 31 and the core wrap sheet 32 is increased, and the core wrap sheet 32 is used even after a lapse of time. Is less likely to peel off from the absorbent core 31. As a result, it is possible to prevent an unnecessary gap from being generated between the absorbent core 31 and the core wrap sheet 32.

In the present invention, the squeezing groove 40 is a first squeezing groove 41 inclined in one direction with respect to a virtual line P extending parallel to the longitudinal direction of the absorber, and a second squeezing groove 41 inclined to the other side with respect to the virtual line P. It is preferable to include the squeeze groove 42. In this case, it is particularly preferable that the first squeezing groove 41 and the second squeezing groove 42 intersect with each other. Further, the squeezing groove 40 may form an oblique lattice-like pattern.

By providing the first squeezing groove 41 and the second squeezing groove 42 inclined in different directions as in the above configuration, the body fluid can be diffused in various directions through these squeezing grooves. In particular, since these squeezing grooves intersect with each other, the body fluid diffuses in at least four directions at this intersection, so that the diffusion efficiency of the body fluid increases. Further, since the absorbent core 31 and the core wrap sheet 32 are relatively strongly bonded at the intersection of the squeezed grooves, the core wrap sheet 32 is separated from the absorbent core 31 by providing such an intersection of the squeezed grooves. The situation can be suppressed more effectively. Further, in the region near the intersection of the squeezing grooves, the constituent fibers of the core wrap sheet 32 bite more strongly into the gaps of the absorbent polymer in the absorbent core 31, so that the anchor effect of the absorbent polymer can be more effectively exhibited.

In the present invention, it is preferable that the absorbent polymer is mainly composed of sodium polyacrylate. Specifically, the absorbable polymer may be composed of at least 80% by weight or more of sodium polyacrylate, and may be composed of only sodium polyacrylate.

The absorbable polymer can be selected from hydrophilic polymers having known crosslinked structures such as polyacrylic acid salt type, polysulfonate type, maleic anhydride type, polyacrylamide type, and polyvinyl alcohol type. Of these, the sodium polyacrylate-based absorbent polymer has good compatibility with the core wrap sheet 32 (particularly those made of spunbonded non-woven fabric), and exerts the above-mentioned anchor effect more effectively.

In the present invention, the absorbent polymer included in the above range preferably has a relatively slow swelling rate. Specifically, the absorbable polymer located in the groove-forming region has a water retention ratio of 37 g / g or more, and is a DW 5-minute value which is the absorption amount when the water-absorbent polymer is immersed in physiological saline for 5 minutes. Is preferably 60 ml / g or less.

As described above, in the present invention, the absorbent polymer is located near the surface of the absorbent core 31 on the side where the squeeze groove 40 of the absorbent core 31 is formed (at least one side when formed on both sides). Many 31b are arranged. In this case, if the swelling rate of the absorbent polymer 31b is high and the gel is immediately gelled, a gel block is formed near the surface of the absorbent core 31, and the body fluid is less likely to permeate inside. Therefore, as the absorbent polymer, a polymer having a water retention ratio of 37 g / g or more, which can absorb a relatively large amount of water, and a DW5 minute value of 60 ml / g or less, which has a slow water absorption rate, is used. It is possible to avoid the immediate occurrence of gel blocks such as.

In the present invention, the core wrap sheet 32 is preferably made of a non-woven fabric. In particular, the core wrap sheet 32 is preferably a spunbonded non-woven fabric.

As the core wrap sheet 32, sanitary paper such as tissue paper is generally used. On the other hand, in the present invention, by adopting a non-woven fabric having high elasticity and fine fibers on the surface as the core wrap sheet 32, the constituent fibers of the core wrap sheet 32 are absorbed in the absorbent core 31. It becomes easier to bite between the sex polymers 31b. As a result, the bonding strength between the core wrap sheet 32 and the absorbent core 31 is improved.

In the present invention, the absorbent polymer 31b included in the above range preferably has an average roundness of 0.4 or more. The roundness of the granular absorbent polymer is represented by 4π × (area) / (perimeter squared) for the captured image.

As described above, in the present invention, the absorbent polymer 31b is provided near the surface of any side of the absorbent core 31 on which the squeezing groove 40 is formed (at least one of the two sides, if formed on both sides). Place many. In this case, if the absorbent polymer 31b is rugged with many corners, when the core wrap sheet 32 and the absorbent core 31 are pressed at the same time, the core wrap sheet 32 bites between the absorbent polymer 31b. It may become too strong. That is, the core wrap sheet 32 is damaged by the absorbent polymer 31b having many corners, and in the worst case, the core wrap sheet 32 is torn. In order to prevent such a situation, in the present invention, it is preferable to use an absorbent polymer 31b located in the groove forming region having a high roundness and a small angle. That is, according to such a configuration, the absorbent core 31 and the core wrap sheet 32 are appropriately bonded by the anchor effect of the absorbent polymer 31b, and the damage caused by the absorbent polymer 31 to the core wrap sheet 32 is effective. Can be reduced to.

According to the present invention, in an absorber in which a squeeze groove is formed between the core wrap sheet and the absorbent core, peeling of the core wrap sheet and the absorbent core can be suppressed.

FIG. 1 is a developed view showing an absorbent article including an absorber according to an embodiment of the present invention. FIG. 2 is an exploded view for explaining a component of an absorbent article including an absorber according to an embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the line III-III shown in FIG. FIG. 4 is an enlarged plan view of the absorbent main body in the embodiment shown in FIG. 1, showing a state in which the side sheet is removed. FIG. 5 is an enlarged cross-sectional view taken along the line VV shown in FIG.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the forms described below, and includes those appropriately modified from the following forms to the extent apparent to those skilled in the art.

In the specification of the present application, the "longitudinal direction" means the direction connecting the ventral portion and the dorsal portion of the wearer when worn in the absorber, and the predecessor in the absorbent article (disposable diaper, etc.). It means the direction connecting the body and the back body. Further, the "width direction" means a direction orthogonal to the longitudinal direction in a plane. Further, the "thickness direction" is a direction three-dimensionally orthogonal to the plane of the absorber or the absorbent article, and specifically, connects the skin facing surface side and the skin non-facing surface side of the absorber. Direction, the direction in which the top sheet, absorber, and back sheet of the absorbent article are laminated. In the figures of the present application, the "longitudinal direction" is indicated by the Y axis, the "width direction" is indicated by the X axis, and the "thickness direction" is indicated by the Z axis.
Further, in the specification of the present application, the “skin facing surface” means a surface facing the wearer's skin when the absorbent body or the absorbent article is worn. Further, the “non-skin facing surface” means a surface that does not face the wearer's skin when the absorber or the absorbent article is worn, that is, a surface opposite to the skin facing surface.
Further, in the specification of the present application, "A to B" means "A or more and B or less".

An absorber according to the present invention and an embodiment of the absorbent article 100 including the absorber will be specifically described with reference to FIGS. 1 to 5. In the illustrated embodiment, the absorbent article 100 according to the present invention is a so-called pants-type disposable diaper. However, the present invention is not limited to this, and can be applied to, for example, a so-called tape-type disposable diaper in which a fastening tape attached to the back body is attached to the front body and worn. In addition, the present invention is applicable to known absorbent articles such as sanitary products for women, light and moderate incontinence pads, and excretion treatment products for pets.

There are two types of pants-type disposable diapers: so-called integrated type and separate type. The illustrated embodiment is an integrated type pants-type disposable diaper, which is absorbed mainly from the crotch part on the skin-facing surface side of the exterior body integrally formed by hanging from the front body through the crotch part to the back body. The sex body is fixed. On the other hand, in the separate type pants-type disposable diaper, the absorbent body is fixed so as to be bridged between the separated front body exterior body and the back body exterior body. In the case of the separate type, there is a gap between the front body exterior body and the back body exterior body, and the exterior body is not provided at the covering position of the crotch part of the absorbent body. In the following, the contents of the present invention will be specifically described by taking an integrated type of these pants-type disposable diapers as an example.

FIG. 1 shows an unfolded state of the pants-type disposable diaper 100 according to the present embodiment, FIG. 2 shows a state in which the pants-type disposable diaper 100 is disassembled into components, and FIG. 3 is III in FIG. The cross-sectional structure along line III is schematically shown. Further, FIG. 4 is an enlarged plan view of the absorbent main body 5, and FIG. 5 is an enlarged cross-sectional view taken along the VV shown in FIG. As shown in FIG. 1, the disposable diaper 100 has a longitudinal direction (Y-axis direction) and a width direction (X-axis direction). The disposable diaper 100 is divided in the longitudinal direction into a front body 1 that contacts the wearer's abdomen when worn, a back body 2 that contacts the wearer's back, and a crotch 3 that is applied to the wearer's inseam. Will be done. Further, in the present embodiment, the disposable diaper 100 includes an exterior body 6 integrally formed from the front body 1 through the crotch part 3 to the back body 2. Further, on the skin-facing surface side of the exterior body 6, the absorbent main body 5 is arranged so as to extend from the crotch portion 3 to the front body 1 and the back body 2.

From the unfolded state shown in FIG. 1, the left and right side portions of the front body 1 and the rear body 2 in the width direction are joined in a state of being superposed on each other. As a result, side seal portions 4 are formed on the left and right ends of the front body 1 and the rear body 2. In this way, in the side seal portion 4, the front body 1 and the rear body 2 are joined to each other to assemble from the unfolded state shown in FIG. 1 to the pants-shaped state. In the pants-type disposable diaper 100, a waist opening is formed by the upper end edge of the front body 1 and the upper end edge of the back body 2. Further, by joining the front body 1 and the back body 2 at the side seal portion 4, a pair of leg openings located around the left and right legs of the wearer are formed at the time of wearing. Therefore, the wearer can put on the pants-type disposable diaper 100 by inserting both legs from the waist opening and pulling out each leg from the leg opening.

In the present embodiment, the absorbent main body 5 has an elongated rectangular shape extending in the longitudinal direction of the disposable diaper, and extends from the front body 1 of the disposable diaper to the back body 2 through the crotch part 3. It is fixed to the skin-facing surface side of the exterior body 6. The absorbent body 5 basically has a liquid-permeable top sheet 10, a liquid-impermeable back sheet 20, and an absorber 30 interposed between them. The top sheet 10 covers the skin facing surface side of the absorber 30, and the back sheet 20 covers the skin non-facing surface side of the absorber 30. Around the absorber 30, the top sheet 10 and the back sheet 20 are bonded to each other by a hot melt adhesive, a heat seal, an ultrasonic seal, or the like. As a result, the absorber 30 is surrounded by the joint portion between the top sheet 10 and the back sheet 20. Further, a pair of three-dimensional gathers 50 are formed on both the left and right sides of the absorbent body 5 in the width direction. The pair of three-dimensional gathers 50 stand on both the left and right sides of the absorber 30 and function as a leak-proof wall for preventing urine leakage.

The top sheet 10 is a sheet-like member that comes into direct contact with the skin of the wearer's inseam and allows body fluid such as urine to permeate through the absorber 30. Therefore, the top sheet 10 is made of a highly flexible liquid-permeable material. The liquid permeability means, for example, the property of permeating water in less than 1 minute when 5 ml of water at room temperature is placed on it under standard atmospheric pressure. Examples of the liquid permeable material constituting the top sheet 10 are a woven fabric, a non-woven fabric, or a porous film. Further, for example, fibers of a thermoplastic resin such as polypropylene, polyethylene, polyester, or nylon may be hydrophilized to form a non-woven fabric. Examples of the non-woven fabric include an air-through non-woven fabric, a point-bonded non-woven fabric, a spunbonded non-woven fabric, and a melt-blown non-woven fabric.

The back sheet 20 is a sheet-like member for preventing the body fluid that has passed through the top sheet 10 and is absorbed by the absorber 30 from leaking to the outside of the diaper. Therefore, the back sheet 20 is preferably made of a liquid-impermeable material. Liquid impermeable means, for example, the property that when 5 ml of water at room temperature is placed on it under standard atmospheric pressure, the water does not permeate even after 1 minute or more. An example of the liquid-impermeable material constituting the back sheet 20 is a liquid-impermeable film made of polyethylene resin. In particular, as the back sheet 20, it is preferable to use a microporous polyethylene film in which a plurality of fine pores of 0.1 to 4 μm are formed in order to secure air permeability while maintaining liquid impermeableness.

The absorber 30 is a member for absorbing body fluid such as urine and holding the absorbed body fluid. The absorber 30 is composed of an absorbent core 31 and a core wrap sheet 32 that covers the absorbent core 31. Most of the absorbent core 31 is composed of hydrophilic fluff pulp 31a obtained by crushing a fiber material such as softwood or hardwood, and granular absorbent polymer 31b (SAP) is contained in the fluff pulp 31a. It is mixed. The fluff pulp 31a is an aggregate of fibers formed by entwining ultrafine fiber materials, and the absorbent polymer 31b is buried and held in the absorbent polymer 31b by being mixed with the fiber material.

Specifically, the fluff pulp 31a includes, for example, pulp fibers such as coniferous or broadleaf trees, short fibers of cellulose fibers such as rayon fibers or cotton fibers, and polyethylene, polypropylene, or polyethylene terephthalate. It may be a short fiber obtained by subjecting a synthetic fiber to a hydrophilic treatment. One of these fibers may be used alone, or two or more of these fibers may be used in combination.

Further, as the absorbent polymer 31b, various materials conventionally used as an absorber material in an absorbent article such as a disposable diaper or a urine pad can be used. As the absorbent polymer 31b, for example, a polymer capable of absorbing and retaining water 5 times or more and 1000 times or less its own weight is adopted. Further, as the absorbent polymer 31b, for example, a starch-based, cellulosic-based, or synthetic polymer-based one may be used. In particular, in the present invention, it is preferable to use an absorbent polymer 31b mainly composed of sodium polyacrylate. Specifically, the absorbent polymer 31b is preferably composed of at least 80% by weight or more of sodium polyacrylate, and may be composed of only sodium polyacrylate.

The core wrap sheet 32 wraps the absorbent core 31 to prevent the fluff pulp 31a and the water-absorbing polymer 31b from leaking out. The core wrap sheet 32 is preferably made of a hydrophilic non-woven fabric having softness and strength. Examples of the non-woven fabric constituting the core wrap sheet 32 include those obtained by hydrophilizing spunbonded non-woven fabric, air-through non-woven fabric, point-bonded non-woven fabric, spunlace non-woven fabric and the like. In particular, it is preferable to use a spunbonded non-woven fabric from the viewpoint of permeability and softness of urine and the like and strength required for shape retention of the absorbent core 31. However, as the core wrap sheet 32, known tissue paper or the like can be used in addition to the non-woven fabric.

The pair of three-dimensional gathers 50 stand on both the left and right sides of the absorber, and serve as a leak-proof wall for preventing urine leakage. Each of the pair of three-dimensional gathers 50 is composed of a side sheet 51 and one or a plurality of elastic elastic members 52. In the crotch portion 3, the outer portion of the side sheet 51 in the width direction is joined to the skin-facing surface side of the top sheet 10 and the back sheet 20, and the inner portion in the width direction is opened without being joined. Then, one or a plurality of elastic elastic members 52 are fixed to the inner end of the opened side sheet 51 in an extended state along the longitudinal direction. Therefore, when the elastic elastic member 52 contracts, the inner end portion of the side sheet 51 rises due to the contraction force of the elastic elastic member 52, and wrinkles (gathers) are formed at the portion where the elastic elastic member 52 contracts. As the side sheet 51, for example, a non-woven fabric sheet obtained by a manufacturing method such as card embossing or spunbond can be used, and it is particularly preferable to use a non-woven fabric sheet such as SMS or SMMS having high waterproofness and breathability.

The exterior body 6 is a member for holding the above-mentioned absorbent body 5 in the inseam of the wearer. The exterior body 6 has an inner sheet 60 located on the skin facing surface side and an outer sheet 70 located on the skin non-facing surface side. The inner sheet 60 and the outer sheet 70 are overlapped with each other and joined by a hot melt adhesive or the like. The inner sheet 60 and the outer sheet 70 are each preferably made of a non-woven fabric or the like that feels good to the touch.

Further, the exterior member 6 has a waist elastic member 81 arranged on the periphery of the waist opening of the disposable diaper, and a pair of left and right leg elastic members 82 arranged at positions along the leg opening. The waist elastic member 81 and the leg elastic member 82 are arranged in an extended state between the inner seat 60 and the outer seat 70. The waist elastic member 81 narrows the waist opening corresponding to the wearer's waist portion, and waist gathers are formed here. Further, the pair of left and right leg telescopic members 82 narrow the pair of left and right leg openings corresponding to the thighs of both legs of the wearer, and leg gathers are formed there.

Here, as shown in FIGS. 4 and 5, a plurality of squeezing grooves 40 in which the absorber 30 is recessed in the thickness direction are formed in the absorbent body 5. More specifically, the squeezing groove 40 is formed by simultaneously pressing the top sheet 10, the core wrap sheet 32, and the absorbent core 31 from the skin-facing surface side of the absorbent body 5. As a result, a squeeze groove 40 is formed in the thickness direction over the top sheet 10, the core wrap sheet 32, and the absorbent core 31. As described above, the squeezing groove 40 can be formed by pressing and compressing the top sheet 10 and the absorber 30 from the skin facing surface side. Therefore, in the portion where the squeeze groove 40 is formed, the densities of the fluff pulp 31a and the absorbent polymer 31b constituting the absorbent core 31 increase.

As shown in FIG. 4, the squeeze groove 40 has a first squeeze groove 41 inclined in one direction with respect to the virtual line P extending parallel to the longitudinal direction of the disposable diaper, and the squeeze groove 40 on the opposite side with respect to the virtual line P. Includes a sloping second squeeze groove 42. A plurality of the first squeezing grooves 41 and the second squeezing grooves 42 are formed, and the plurality of first squeezing grooves 41 are all parallel (the inclination angles with respect to the virtual line P are equiangular), and similarly, the plurality of second squeezing grooves 41 are formed. The grooves 42 are also all parallel (the inclination angles with respect to the virtual line P are equiangular). Further, the first squeezing groove 41 and the second squeezing groove 42 intersect with each other. Specifically, each of the first squeezing grooves 41 preferably intersects with a plurality of second squeezing grooves 42, and similarly, each of the second squeezing grooves 42 has a plurality of first squeezing grooves 41. It is preferable that it intersects with.

More specifically, in FIG. 4, the squeezing grooves 40 formed in the top sheet 10 and the absorber 30 are formed in an oblique lattice pattern. The "oblique grid pattern" referred to here is a pattern in which a plurality of squeezing grooves extending in a direction inclined with respect to the longitudinal direction and the width direction intersect to partition an oblique (diamond) non-squeezed region. Say. Therefore, the angle θ at which each squeeze groove is inclined with respect to the virtual line P extending parallel to the longitudinal direction is less than 90 degrees, particularly in the range of 20 to 80 degrees, 30 to 60 degrees, or 40 to 50 degrees. It is preferable to have. In the illustrated example, the inclination angle θ of each squeezing groove is 45 degrees. Further, the oblique lattice pattern is a regular pattern in which all the non-compressed regions 43 surrounded on all sides by the respective pressing grooves 41 and 42 are in the regular oblique shape (regular rhombus). As described above, in the oblique lattice pattern, a plurality of first squeezed grooves 41, a plurality of second squeezed grooves 42, a non-squeezed region 43 surrounded by these squeezed grooves 41 and 42, and a first squeezed groove 41. It can be considered that the intersection 44 where the pressing groove 41 and the second pressing groove 42 intersect is formed.

Here, specific numerical values relating to the absorber 30 will be described. The thickness of the absorber 30, that is, the thickness of the non-squeezed region 43 is preferably 10 mm to 40 mm, and particularly preferably 15 mm to 30 mm. The depth of the squeezing groove 40 is preferably 30 to 95%, particularly preferably 50 to 95% or 60 to 95% with respect to the thickness of the absorber 30. For example, the thickness of the absorber 30 at the site where the squeeze groove 40 is formed may be at least 1 mm or more, and particularly preferably 2 mm or more or 5 mm or more.

The width of the squeezing groove 40 is preferably 1 mm to 5 mm, particularly preferably 2 mm to 4 mm. The diagonal length D1 of the non-squeezed region 43 shown in FIG. 4 in the longitudinal direction is preferably 10 mm to 50 mm, particularly preferably 20 mm to 40 mm or 30 mm. Further, the preferable numerical range of the diagonal length D2 in the width direction of the non-squeezed region 43 is the same as the above-mentioned length D1. The length D1 and the length D2 are preferably approximately equal, but may be different. The shape of the non-squeezed region 43 is not limited to the regular oblique shape (regular rhombus), and other oblique shapes can be used.

Further, the squeezing groove 40 formed in the absorber 30 is formed in a wide range in the longitudinal direction so that the body fluid discharged in the vicinity of the lower crotch can be widely diffused to the front body and the back body. Is preferable. Specifically, the longitudinal length of the region in which the squeezing groove 40 is formed is preferably 60% or more with respect to the longitudinal length of each absorber 30, 60% to 100%, 70. It is particularly preferably% to 100%, or 80% to 100%. Further, the squeezing groove 40 formed in the absorber 30 is formed in a wide range in the width direction so that the body fluid discharged near the center in the width direction can be widely diffused to the outside in the width direction. Is preferable. Specifically, the maximum width in the width direction of the region where the squeeze groove 40 is formed is preferably 60% or more with respect to the minimum width in the width direction of each absorber 30, and is 60% to 100%, 70. It is particularly preferably% to 100%, or 80% to 100%.

In the enlarged cross-sectional view shown in FIG. 5, the absorbent polymer 31b contained in the absorbent core 31 is schematically indicated by a “black circle”. The absorbent core 31 absorbs on the side where the squeezed groove 40 is formed of the absorbent core 31 in the region near the squeezed groove 40, that is, at least in the groove forming region within 3 mm in the plane direction from the squeezed groove 40. The density of the absorbent polymer located near the surface of the sex core 31 is high. Specifically, when the composition of the absorbent core in the thickness range within 10% from the skin surface surface of the absorbent core with respect to the thickness of the entire absorbent core 31 is 100 parts by mass in half. In addition, the amount of the absorbent polymer is 50 parts by mass or more. In particular, the density of the absorbent polymer 31b is preferably 55 to 80 parts by mass, and particularly preferably 60 to 75 parts by mass.
In the present invention, the "configuration of the absorbent core in the thickness range within 10% from the skin surface surface of the absorbent core" will be described in more detail as the non-squeezed region (skin facing surface) of the absorbent core 31. Based on the thickness of the region where the squeezing groove does not exist on either the side or the non-skin facing surface side, at least one of the squeezing grooves 40 of the absorbent core is formed (if both sides are formed). It means the configuration of the absorbent core in the thickness range within 10% from the surface of the absorbent core 31 (on the side of) (based on the surface position of the portion where the squeeze groove 40 does not exist on the surface).

The density of the absorbent polymer described above, that is, the compounding ratio of the absorbent polymer in the absorbent core can be measured according to the following method.
<Measurement of the compounding ratio (part by weight) of the absorbent polymer in the absorbent core>
In advance, an arbitrary weight of absorbent polymer is taken out as a sample from the absorbent core to be measured, neutralization titration is performed using 1 mol / L hydrochloric acid, a calibration curve is prepared, and the polymer coefficient of the sample is calculated (note that the polymer coefficient of the sample is calculated. The polymer coefficient depends on the type of polymer).
Next, the core in the range to be measured (thickness range within 10% from the skin surface surface) is taken out, and the projected area on the core plane in that range and the weight of the taken out core are measured.
After that, the core taken out is put into ion-exchanged water in which an appropriate amount of sodium chloride is dissolved, and then 1 ml of 1 mol / L hydrochloric acid is injected, and the value of the pH meter for measuring the pH of the ion-exchanged water is large. Read the injection volume of 1 mol / L hydrochloric acid at the time of fluctuation. The product of the read value and the polymer coefficient described above is the weight of the absorbent polymer contained in the core taken out. Based on this weight and the weight of the removed core measured above, the weight part of the absorbent polymer contained in the removed core is calculated, with the entire removed core as 100 parts by weight.
The range in the plane direction of the absorber of the core to be taken out may be the entire area of the absorber if the configuration in the thickness direction of the absorber is substantially uniform over most of the absorber, or the present invention. It may be any part of the absorber (for example, a region of 1 cm to 5 cm square) in view of the relationship with the effect of. Further, for example, even when the configuration of the absorber in the thickness direction is not substantially uniform, a corner within the range around the squeezing groove (for example, the groove forming region within 3 mm in the plane direction from the squeezing groove 40) is taken out. May be. In the present invention, it is sufficient that the condition of the blending ratio of the absorbent polymer is satisfied for the core sample taken out from at least one of the above-mentioned extraction ranges.

As described above, the absorbent core 31 is absorbed within a thickness range of 1 mm from the surface of the absorbent core 31 on the side where the squeeze groove 40 is formed (at least one side when formed on both sides). By arranging the sex polymer at a high density, the core wrap sheet 32 and the absorbent core 31 are pressed simultaneously from the skin facing surface, the skin non-facing surface side, or both to form the squeezing groove 40. The constituent fibers of 32 will firmly bite between the absorbent polymers 31b in the absorbent core 31. In this way, by exerting the anchor effect of connecting the core wrap sheet 32 to the absorbent core 31, the bonding strength between the absorbent core 31 and the core wrap sheet 32 is increased, and the core wrap sheet 32 is used even after a lapse of time. Is less likely to peel off from the absorbent core 31. As a result, it is possible to prevent an unnecessary gap from being generated between the absorbent core 31 and the core wrap sheet 32.

Further, the absorbent polymer 31b arranged in the groove forming region, particularly the absorbent core 31 on the side where the squeezed groove 40 of the absorbent core 31 is formed (in the case where it is formed on both sides, at least one side). Those located within 1 mm from the surface of the polymer preferably have the following water retention characteristics. That is, it is preferable that the absorbent polymer 31b has a water retention ratio of 37 g / g or more and a DW 5-minute value (absorption amount when the water-absorbent polymer is immersed in physiological saline for 5 minutes) of 60 ml / g or less. The range of the water retention ratio is, for example, preferably 37 to 100 g / g, and particularly preferably 50 to 100 g / g. The range of the DW 5-minute value is preferably 5 to 60 ml / g, and particularly preferably 10 to 50 g / g.

The water retention ratio and the DW 5-minute value of the above-mentioned absorbent polymer can be measured according to the following method.
<Measurement of water retention ratio>
For the water retention ratio, 1 gram of absorbent polymer particles were weighed in a tea bag, immersed in physiological saline at 25 ° C. for 1 hour, the absorption amount was measured, and then centrifugal dehydration was performed at 450 G to determine the water retention ratio. .. Unless otherwise specified, all measurements in the present application are performed in a constant temperature and humidity chamber at 20 ° C. and 65% RH.
<Measurement of DW 5-minute value>
1.000 g of absorbent polymer particles were weighed and sprayed as evenly as possible on a 250 mesh nylon mesh set in a DW measuring device, and the amount of physiological saline absorbed was read. As the initial absorption amount, the amount absorbed in 5 minutes (ml / g) was read and used as the DW 5-minute value. The DW measuring device used for the measurement was a Demand Wettability Tester manufactured by Scientific Machine & Supplies Co. LTD, and the 250 mesh nylon mesh was N-NO.250HD manufactured by NBC Industries.

As described above, in the present invention, the absorbent polymer is located near the surface of the absorbent core 31 on the side where the squeeze groove 40 of the absorbent core 31 is formed (at least one side when formed on both sides). Many 31b are arranged. In this case, if the swelling rate of the absorbent polymer 31b is high and the gel is immediately gelled, a gel block is formed near the surface of the absorbent core 31, and the body fluid is less likely to permeate inside. Therefore, as the absorbent polymer, a polymer having a water retention ratio of 37 g / g or more, which can absorb a relatively large amount of water, and a DW5 minute value of 60 ml / g or less, which has a slow water absorption rate, is adopted. It is possible to avoid the above-mentioned gel block from occurring immediately.

Further, the absorbent polymer 31b arranged in the groove forming region, particularly the absorbent core 31 on the side where the squeezed groove 40 of the absorbent core 31 is formed (at least one side when formed on both sides). Those located within a thickness range of 1 mm or less from the surface of the polymer preferably have an average roundness of 0.4 or more. The roundness of the granular absorbent polymer is expressed by the ratio of the minor axis to the major axis of the particles.

<Measurement of average roundness>
The absorbent polymer 31b located in the groove forming region within 3 mm in the plane direction from the squeezing groove 40 was collected in a granular state, and a photograph was taken at a magnification of 50 times using an electron microscope (Keyence VHX2000 / D500). Save the image in JPEG format. Load the captured image file into Mathematica10 (Wolfram Research) and perform image processing using the following command.
・ Bilateral Filter [image name, 7, 0.1]
・ Binarize [%]
After saving the processed image, load it into image processing software (ImageJ). After loading into ImageJ, invert black and white with the Invert command, binarize the particle part with the Threshold command, and then measure the roundness (select ShapeDiscriptor with the SetMesurement command) with the AnalyzeParticles command (select ShapeDiscriptor with the SetMesurement command). About 50 to 100 points). When measuring roundness, set to reject objects with 100 pixels ^ 2 or less. Take the arithmetic mean of the measured roundness, and use that value as the average roundness of the particle shape of the absorbent polymer of the present invention.

As described above, in the present invention, the absorbent polymer is located near the surface of the absorbent core 31 on the side where the squeeze groove 40 of the absorbent core 31 is formed (at least one side when formed on both sides). Many 31b are arranged. In this case, if the absorbent polymer 31b is rugged with many corners, when the core wrap sheet 32 and the absorbent core 31 are pressed at the same time, the core wrap sheet 32 bites between the absorbent polymer 31b. It may become too strong. That is, the core wrap sheet 32 is damaged by the absorbent polymer 31b having many corners, and in the worst case, the core wrap sheet 32 is torn. In order to prevent such a situation, in the present invention, it is preferable to use an absorbent polymer 31b located in the groove forming region having a high sphericity and a small angle. That is, according to such a configuration, the absorbent core 31 and the core wrap sheet 32 are appropriately bonded by the anchor effect of the absorbent polymer 31b, and the damage caused by the absorbent polymer 31 to the core wrap sheet 32 is effective. Can be reduced to.

The average particle size of the absorbent polymer 31b used in the present invention is preferably 1000 μm or less when not absorbed. The absorbent core 31 preferably contains 99% by weight or more of the absorbent polymer 31b having a particle size of 106 μm or more when not absorbed, and particularly contains 99% by weight or more of the absorbent polymer 31b having a particle size of 150 to 850 μm. It is preferable that The average particle size of the absorbent polymer 31b when not absorbed may be about 250 to 500 μm. Further, it is preferable that the average particle size of the absorbent polymer 31b after absorption is three times or more, specifically 500 μm or more, of the average particle size when not absorbed.

The definitions of the average particle size of the absorbable polymer when not absorbed and when absorbed are as follows.
<Measurement of average particle size>
The average particle size of the highly absorbent polymer particles when not absorbed means the particle size at an integrated value of 50% in the weight-based particle size distribution. The weight-based particle size distribution in this case is measured according to JIS Z8815-1994. That is, 710 μm, 500 μm, 300 μm, 150 μm, and 106 μm open-opening sieves having an inner diameter of 150 mm and a depth of 45 mm are stacked with the narrow-opening sieve facing down, and above the topmost wide-opening 710 μm sieve. Put 50 g of the measurement sample in the sample, sift with a sieve vibrator for 10 minutes, weigh the measurement sample remaining on each sieve, and measure the measurement sample remaining on each sieve based on the weight of the first measurement sample. Measured by determining% by weight. In addition, the particle size after absorption is integrated in the number-based particle size distribution obtained with the representative diameter as the maximum diameter on the major axis using a still image analysis technique such as a particle image analyzer (Moforogy G3 manufactured by Malvern: still image analysis). It means the particle size at a value of 50%.

As described above, in the specification of the present application, in order to express the content of the present invention, the embodiments of the present invention have been described with reference to the drawings. However, the present invention is not limited to the above embodiment, and includes modifications and improvements which are obvious to those skilled in the art based on the matters described in the present specification.

INDUSTRIAL APPLICABILITY The present invention can be suitably used in the manufacturing industry of an absorber that is attached to the inseam of a wearer to absorb and retain a liquid such as urine, and an absorbent article such as a disposable diaper.

1 ... Front body 2 ... Back body 3 ... Inseam 4 ... Side seal 5 ... Absorbent body 6 ... Exterior 10 ... Top sheet 20 ... Back sheet 30 ... Absorber 31 ... Absorbent core 31a ... Fluff pulp 31b ... Absorbent Sex polymer 32 ... Core wrap sheet 40 ... Squeezed groove 41 ... 1st squeezed groove 42 ... 2nd squeezed groove 43 ... Non-squeezed area 44 ... Intersection 50 ... Solid gather 51 ... Side sheet 52 ... Elastic elastic member 60 ... Inner sheet 70 ... Outer sheet 81 ... Waist elastic member 82 ... Leg elastic member 100 ... Absorbent article (disposable diaper)

Claims (6)

An absorbent core (31) having at least a granular absorbent polymer (31b) and
It has a core wrap sheet (32) that covers at least one of the skin-facing surface and the skin-non-facing surface of the absorbent core (31).
An absorber in which a plurality of linear pressing grooves (40) are formed in the thickness direction over the core wrap sheet (32) and the absorbent core (31).
The absorbent core (31) is 10 from any of the surfaces on which the squeezed groove (40) of the absorbent core (31) is formed, based on the thickness of the non-squeezed region of the absorbent core (31). structure in the thickness range within percent, when the total weight of the range is 100 parts by weight, the absorbent polymer contained in the range (31b) is Ri der 50 parts by weight or more, and the thickness The absorbent polymer (31b) is arranged at a higher density than the range other than the range.
The squeeze groove (40) is a first squeeze groove (41) inclined in one direction with respect to a virtual line (P) extending parallel to the longitudinal direction of the absorber, and the other side with respect to the virtual line (P). An absorber that includes a second squeezing groove (42) inclined to the side, and the first squeezing groove (41) and the second squeezing groove (42) intersect . The absorber according to claim 1 , wherein the depth of the squeeze groove (40) is 30 to 95% with respect to the thickness of the absorber (30) . All SANYO said absorbent polymer (31b) is composed mainly of sodium polyacrylate,
The absorber according to claim 1 or 2, wherein the core wrap sheet (32) is made of a non-woven fabric . The absorbent polymer (31b) included in the range is
The water retention ratio is 37 g / g or more,
The absorber according to any one of claims 1 to 3, wherein the DW 5-minute value, which is the amount absorbed when the water-absorbent polymer is immersed in physiological saline for 5 minutes, is 60 ml / g or less. The absorber according to any one of claims 1 to 5, wherein the absorbent polymer (31b) included in the range has an average roundness of 0.4 or more. An absorbent article comprising the absorber according to any one of claims 1 to 5 .

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