JP4724499B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article in which an absorbent body is formed by an aggregate of hardly absorbent filaments such as cellulose acetate.

  Absorbent articles such as infant and adult tape-type and pants-type disposable diapers and sanitary napkins are used between the top sheet on the use side, the back sheet that prevents permeation of body fluids on the back side, and between these sheets. The basic element is an absorption element that receives and holds excreted body fluid that has permeated through the top sheet.

  For this basic element, an exterior sheet made of, for example, a non-woven fabric is provided on the back side of the back sheet, and a form for improving the touch when a plastic sheet is used as the back sheet, a form for forming so-called barrier cuffs on both sides of the product, etc. In order to improve the fit around the waist and the abdomen, a form for imparting elastic stretchability is appropriately added.

  As an absorbent element that receives and holds the body fluid that has passed through the top sheet on the use surface side, conventionally, a fiber stack of pulp staple fibers is generally used. It is also known to use superabsorbent polymer particles (hereinafter also referred to as “SAP”) to increase the amount of absorption in body fluids.

  In addition to the case where the SAP is spread on the piled fiber of the short pulp fibers, there is a case where the SAP of the short pulp fibers is dispersed and held (Patent Document 1).

  On the other hand, in recent years, as shown in JP-T-2002-524399 (WO99 / 27879: Patent Document 2) and JP-T-2004-500165 (US Pat. No. 6,646,180: Patent Document 3), cellulose acetate It has been proposed to use tow as an absorbent element.

JP-T-2004-500165 discloses an absorbent element mainly composed of SAP and added with a filament assembly. This absorbent element is a laminate comprising an absorbent layer between about 50 to 95% by weight of SAP and about 5 to 50% by weight of a water-insoluble hydrophilic polymer such as starch and fibers, provided between an upper layer and a lower layer. This is a structure, which is folded into a C-shaped cross section and a channel is formed in the center.
JP 2004-65300 A Special Table 2002-524399 (WO99 / 27879) JP-T 2004-500165 (US Pat. No. 6,646,180)

  However, since filament aggregates such as cellulose acetate have almost no water absorption per se, they are inferior in absorption rate and diffusivity, and there is a possibility that absorption may not be able to catch up when a large amount of urine is excreted rapidly.

  Therefore, the main problem of the present invention is to improve the absorption rate and diffusivity while using the hardly absorbable filament aggregate.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
A top sheet that allows body fluid to permeate, a body fluid impermeable sheet, and an absorbent element provided therebetween,
In the absorbent article , the absorbent element includes an absorbent body and a covering sheet that wraps at least the back and side surfaces of the absorbent body .
The absorber, possess a 1.0-fold following flame absorbent filament aggregate of the artificial urine absorption of its own weight, and superabsorbent polymer fibers,
The difficult-to-absorb filament assembly is formed by opening 3,000-1,000,000 bundled crimped cellulose ester filaments having a fineness of 1-16 dtex,
The high absorption polymer fiber is a short fiber having a water absorption of 30 times or more of its own weight and a fineness of 1.0 to 20 denier,
The superabsorbent polymer fiber is dispersed and mixed in the whole or a part of the aggregate of the hardly absorbent filaments,
The basis weight of the superabsorbent polymer fiber is 30 to 100 g / m ² ;
An absorbent article characterized by the above.

(Function and effect)
The superabsorbent polymer fiber has a larger surface area than the superabsorbent polymer particles, and the liquid can easily diffuse through the surface, so that the absorption rate and the diffusibility are excellent. For this reason, water absorption performance can be supplemented and absorption speed and diffusivity can be improved by using a superabsorbent polymer fiber together with a hardly absorbent filament aggregate having poor water absorption performance.
The amount of artificial urine absorbed according to the present invention is measured by the following procedure.
(1) Weigh 5.0 g of sample fiber and immerse in 1 L of artificial urine for 5 minutes.
(2) Next, the sample is taken out from the artificial urine and suspended for 1 minute.
(3) Next, the liquid is separated for 6 minutes at 2250 rpm using a centrifuge.
(4) Next, the weight of the sample is measured, and the value obtained by subtracting the fiber weight (5.0 g) is taken as the artificial urine absorption amount.
In addition, when the highly absorbent polymer fiber is mixed in the hardly absorbable filament aggregate as described above, the liquid diffusibility is more remarkably improved in combination with the high liquid diffusibility of the hardly absorbable filament aggregate.

<Invention of Claim 2>
The absorbent article according to claim 1, wherein superabsorbent polymer particles are dispersed throughout the thickness direction of the absorber.

(Function and effect)
Although the superabsorbent polymer fiber is excellent in absorption rate and diffusibility, there are problems such as an increase in bulk and a decrease in cost effectiveness when it is attempted to secure an absorption amount by itself. Therefore, it is also preferable to use a combination of superabsorbent polymer particles as necessary. By using the superabsorbent polymer particles in combination, the amount of absorption can be increased at a low cost.

<Invention of Claim 3>
Compression energy based on KES test is 0.01-10.00 gfcm / cm ² And a holding sheet having a holding function and a stiffness reinforcing function of the superabsorbent polymer particles that have come out of the filament aggregate and have a compression resilience of 10 to 100%. The absorptive article according to claim 2 provided between back side parts.
<Invention of Claim 4>
The absorptive article according to any one of claims 1 to 3 which is a disposable diaper.

  As described above, according to the present invention, the absorption rate and diffusibility are improved while using the hardly absorbable filament aggregate.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
<Examples of pants-type disposable diapers>
FIG. 1 shows an example of a pants-type disposable diaper. The pants-type disposable diaper 10 includes an exterior sheet 12 on the outer surface (back surface) side and an absorbent main body 20 on the inner surface (front surface) side, and the absorbent main body 20 is fixed to the exterior sheet 12. The absorptive main body 20 is a portion that receives and absorbs and retains body fluids such as urine and loose stool (menstrual blood in a sanitary napkin described later). The exterior sheet 12 is a part for mounting on the wearer.

  The exterior sheet 12 has, for example, an hourglass shape as shown in the figure, and both sides are constricted, and this is a part into which a wearer's leg is put. The absorptive main body 20 can take any shape, but is rectangular in the illustrated form.

  As shown in FIG. 2, the exterior sheet 12 is folded back and forth after the absorbent main body 20 is installed and fixed at a predetermined position, and joined regions 12A on both sides of the front body 12F and the back body 12B of the exterior sheet 12. Are joined by heat fusion or the like. Thereby, a pants-type disposable diaper having a structure shown in FIG. 1 and having a waist opening WO and a pair of leg openings LO is obtained.

  An intermediate width in the longitudinal direction of the absorbent main body 20 shown in the drawing (that is, the vertical direction in FIG. 2, which is also the front-rear direction of the product) is shorter than the width connecting the constricted portions of the exterior sheet 12. This width relationship may be reversed or the same width.

  The exterior sheet 12 is preferably composed of two sheets of water-repellent nonwoven fabric, for example, and an elastic elastic member is interposed between these sheets, and a form that fits the wearer by the contraction force is desirable. As the elastic elastic member, thread rubber or elastic foam band can be used, but it is desirable to use a large number of thread rubbers. In the illustrated embodiment, the rubber threads 12C, 12C,... Are provided continuously in the width direction in the waist region W, provided only on both sides in the lower waist region U, and not provided in the crotch region L. Since the rubber threads 12C, 12C,... Are provided in both the waist region W and the lower waist region U, even if the shrinkage force of the rubber thread 12C itself is weak, the rubber waist 12C hits the wearer in the lower waist region U as a whole. The product fits well to the wearer.

(Absorbent body)
As shown in FIG. 3, the absorbent main body 20 of the embodiment includes a top sheet 30 made of, for example, a nonwoven fabric that allows body fluid to permeate, an intermediate sheet (second sheet) 40, and an absorbent element 50. A body fluid impermeable sheet (also called a back sheet) 70 made of a plastic sheet or the like is provided on the back side of the absorbent body 56. The exterior sheet 12 is provided on the back side of the body fluid impermeable sheet 70. Further, barrier cuffs 60, 60 are provided on both sides.

(Top sheet)
The top sheet 30 has a property of transmitting body fluid. Accordingly, the material of the top sheet 30 is sufficient if it exhibits this body fluid permeability, and examples thereof include a porous or non-porous nonwoven fabric and a porous plastic sheet. Of these, the nonwoven fabric is not particularly limited as to what the raw fiber is. For example, synthetic fibers such as olefins such as polyethylene and polypropylene, polyesters and polyamides, recycled fibers such as rayon and cupra, natural fibers such as cotton, and mixed fibers and composite fibers using two or more of them. Etc. can be illustrated. Furthermore, the nonwoven fabric may be manufactured by any processing. Examples of the processing method include known methods such as a spunlace method, a spunbond method, a thermal bond method, a melt blown method, a needle punch method, an air through method, and a point bond method. For example, the spun lace method is a preferable processing method for obtaining flexibility and drapeability, and the thermal bond method is for obtaining bulkiness and softness.

  The top sheet 30 may be composed of a single sheet or a laminated sheet obtained by bonding two or more sheets. Similarly, the top sheet 30 may be composed of one sheet or two or more sheets in the planar direction.

(Intermediate sheet)
In order to quickly transfer the body fluid that has permeated through the top sheet 30 to the absorbent body, an intermediate sheet 40 that is generally referred to as a “second sheet” that has a higher body fluid permeation rate than the top sheet 30 can be provided. This intermediate sheet not only improves the absorption performance by the absorbent body by quickly transferring the body fluid to the absorbent body, but also prevents the “reversal” phenomenon of the absorbed body fluid from the absorbent body, and the top sheet 30 is always dried. State.

  Examples of the intermediate sheet 40 include the same materials as the top sheet 30, spunlace, pulp nonwoven fabric, a mixed sheet of pulp and rayon, point bond, or crepe paper. In particular, an air-through nonwoven fabric and a spunbond nonwoven fabric are preferable.

  The intermediate sheet (second sheet) 40 is interposed between the top sheet 30 and the covering sheet 58. As shown in FIG. 5, a configuration in which the intermediate sheet (second sheet) 40 is not provided can also be used.

  The intermediate sheet 40 in the illustrated form is disposed in the center shorter than the width of the absorber 56, but may be provided over the entire width. The length of the intermediate sheet 40 in the longitudinal direction may be the same as the length of the absorbent body 56 or may be within a short length range centered on the region that receives the body fluid. A typical material for the intermediate sheet 40 is a nonwoven fabric having excellent body fluid permeability.

(Absorption element)
The absorption element 50 includes an aggregate of hardly-absorbing filaments 52, 52 ... having an artificial urine absorption amount of 1.0 times or less of its own weight, high-absorption polymer fibers 55, 55 ..., and high-absorption polymer particles 54, 54 ... The body 56 and the covering sheet 58 which wraps at least the back surface and side surface of this absorber 56 are provided. Further, a holding sheet 80 is provided between the absorbent body 56 and the rear surface side portion (lower portion) of the covering sheet 58.

(Non-absorbable filament assembly)
The aggregate of the hardly-absorbing filaments 52, 52... Can be produced by opening a tow (fiber bundle) composed of hardly-absorbing filaments (substantially continuous long fibers). As the material of the flame-absorbing filaments, artificial urine absorption of Ru der 1.0 times or less of its own weight, the cellulose ester.

  Examples of the cellulose ester that can be suitably used include organic acid esters such as cellulose acetate, cellulose butyrate, and cellulose propionate; mixed acid esters such as cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose nitrate acetate. And cellulose ester derivatives such as polycaprolactone-grafted cellulose ester can be used. These cellulose esters can be used alone or in admixture of two or more. The viscosity average degree of polymerization of the cellulose ester is, for example, about 50 to 900, preferably about 200 to 800. The average substitution degree of the cellulose ester is, for example, about 1.5 to 3.0 (for example, 2 to 3).

  The average degree of polymerization of the cellulose ester can be, for example, 10 to 1000, preferably 50 to 900, more preferably about 200 to 800, and the average degree of substitution of the cellulose ester is, for example, about 1 to 3, preferably 1 to 1. 2.15, more preferably about 1.1 to 2.0. The average degree of substitution of the cellulose ester can be selected from the viewpoint of enhancing biodegradability.

  As the cellulose ester, an organic acid ester (for example, an ester with an organic acid having about 2 to 4 carbon atoms), particularly cellulose acetate is suitable. Incidentally, in the case of cellulose acetate, the amount of artificial urine absorbed is about 0.1 to 0.3 times its own weight. The degree of acetylation of cellulose acetate is often about 43 to 62%, but about 30 to 50% is particularly preferable because it is excellent in biodegradability. A particularly preferred cellulose ester is cellulose diacetate.

  The hardly absorbent filament may contain various additives such as a heat stabilizer, a colorant, an oil agent, a yield improver, a whiteness improver and the like.

The fineness of the hardly absorbing filament is 1 to 16 dtex, preferably 1 to 10 dtex, and more preferably 1 to 5 dtex. Filaments, rather than non-crimped fibers are crimped fibers. The crimped degree of the crimped fiber can be, for example, 5 to 75, preferably 10 to 50, and more preferably about 15 to 50 per inch. Further, a crimped fiber that is uniformly crimped is often used. When crimped fibers are used, a bulky and light absorbent body can be produced, and a tow with high unity can be easily produced by entanglement between the fibers. The cross-sectional shape of the filament is not particularly limited, and may be any shape such as a circle, an ellipse, an irregular shape (for example, a Y shape, an X shape, an I shape, an R shape) or a hollow shape. . The filament is used in the form of a tow (fiber bundle) formed by bundling about 3,000 to 1,000,000, preferably about 5,000 to 1,000,000 single fibers. In the present invention, the fiber bundle is formed by concentrating 3,000 to 1,000,000 filaments.

  Since the tow has weak entanglement between filaments, a binder having an action of adhering or fusing the contact portions of the filaments can be used mainly for the purpose of maintaining the shape. Examples of binders include ester plasticizers such as triacetin, triethylene glycol diacetate, triethylene glycol dipropionate, dibutyl phthalate, dimethoxyethyl phthalate, and triethyl citrate, as well as various resin adhesives, especially thermoplastic resins. Can be used.

  The thermoplastic resin used as the binder is a resin that exhibits an adhesive force when melted and solidified, and includes water-insoluble or hardly water-soluble resins and water-soluble resins. A water-insoluble or poorly water-soluble resin and a water-soluble resin can be used together as necessary.

  Examples of water-insoluble or poorly water-soluble resins include polyethylene, polypropylene, ethylene-propylene copolymers, olefinic homo- or copolymers such as ethylene-vinyl acetate copolymers, polyvinyl acetate, polymethyl methacrylate, methacryl Acid methyl-acrylic acid ester copolymer, acrylic resin such as copolymer of (meth) acrylic monomer and styrene monomer, polyvinyl chloride, vinyl acetate-vinyl chloride copolymer, polystyrene, styrene monomer ( Styrenic polymers such as copolymers with (meth) acrylic monomers, optionally modified polyesters, nylon 11, nylon 12, nylon 610, nylon 612 and other polyamides, rosin derivatives (eg, rosin esters), Hydrocarbon resin (eg terpene tree , Dicyclopentadiene resins, and petroleum resins), and hydrogenated hydrocarbon resins. One or two or more of these thermoplastic resins can be used.

  Examples of water-soluble resins include various water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl ether, vinyl monomers, and copolymerizable monomers having a carboxyl group, a sulfonic acid group, or a salt thereof. Vinyl water-soluble resins such as copolymers, acrylic water-soluble resins, polyalkylene oxides, water-soluble polyesters, water-soluble polyamides, and the like can be used. These water-soluble resins can be used alone or in combination of two or more.

  Various additives such as stabilizers such as antioxidants and ultraviolet absorbers, fillers, plasticizers, preservatives, and antifungal agents may be added to the thermoplastic resin.

Since tow can be produced by a known method, it will not be described in detail. Cellulose diacetate tow bales that can be suitably used in the absorbent element 50 are commercially available from Celanese, Daicel Chemical Industries, and the like. Cellulose diacetate tow bale has a density of about 0.5 g / cm ³ and a total weight of 400-600 kg.

  From this bale, the tow is peeled off and spread into a wide band so as to have a desired size and bulk. The opening width of the tow is arbitrary, and can be, for example, a width of 100 to 2000 mm, preferably about 100 to 300 mm of the width of the product absorber. Moreover, the density of an absorber can be adjusted by adjusting the degree of tow opening.

  Tow opening methods include, for example, a method in which the tow is spread over a plurality of opening rolls and the tow width is gradually expanded as the tow progresses, and the tow tension (extension) and relaxation (contraction) And the like, and a method of widening and opening using compressed air can be used.

(High absorption polymer fiber)
The superabsorbent polymer fiber 55 is generally called a superabsorbent fiber, a superabsorbent fiber, or a superabsorbent fiber. As the superabsorbent polymer fiber 55, those having a water absorption amount of 30 times or more, particularly 50 times or more of its own weight can be suitably used. Superabsorbent polymer fibers 55, using short fibers instead of a filament (long fiber). The fineness of the superabsorbent polymer fibers 55, Ru is about 1.0 to 20 denier. The superabsorbent polymer fiber 55 may be a non-crimped fiber or a crimped fiber.

  Examples of such superabsorbent polymer fibers 55 include those obtained by forming a water-absorbing polymer that absorbs water to form a gel, and those obtained by subjecting the outer layer to a water-absorbing process. The Terajin Fibers Co., Ltd. trade name Bel Oasis, which is obtained by directly spinning a polymer mainly composed of polyacrylic acid sodium salt to form a fiber, includes the outer layer subjected to water absorption processing, and the like. And Toyobo Co., Ltd. having a two-layer structure consisting of an inner layer (core) that is an acrylic fiber.

As shown in FIG. 3, the superabsorbent polymer fiber 55 is dispersed and mixed in the entire aggregate (or a part thereof) of the hardly absorbent filaments 52 . Because it is such a mixed form, superabsorbent polymer fibers 55 are short fibers. As shown in the drawing, it is one preferable example that the entire absorbent body 56 is formed of a mixture of the hardly absorbent filament aggregate and the superabsorbent polymer fiber 55.

In contrast, the reference example shown in FIGS. 4 and 5, Ru embodiment der that by laminating a layer 52B in the thickness direction having a set of layers 52A and poorly absorbed filaments 52 having a superabsorbent polymer fibers 55. As one preferred example in this reference example, a two-layer configuration is provided in which the layer 52A having the superabsorbent polymer fiber 55 is the upper layer and the layer 52B having the hardly absorbable filament aggregate is the lower layer throughout the absorber 56. Can do.

Further, in the reference example shown in FIG. 7, the portion 52E having the superabsorbent polymer fiber 55 and the portions 52E and 52F having the aggregate of the hardly absorbable filaments 52 are arranged in the width direction (longitudinal direction, diagonal direction, etc., orthogonal to the thickness direction). Apply predicates form der arranged side by side to be good) in another direction. As one preferred example in this reference example, the portion 52D having the superabsorbent polymer fiber 55 is extended over the entire front and rear direction of the absorbent body 56 at the center in the width direction, and the portions 52E and 52F having the hardly absorbable filament aggregate are made to have a width. The form extended over the whole front-back direction of the absorber 56 on the both sides of a direction can be mentioned.

In the laminated form and the juxtaposed form of these reference examples , the number of layers or juxtaposed parts is not particularly limited, and can be three or more. The filament assembly may not be provided.

Moreover, as another reference example, the superabsorbent polymer fiber 55 is an example of being provided in the absorbent body 56 in various fiber aggregate forms such as a nonwoven fabric, a knitted fabric, and a woven fabric. when using any object, prepared as superabsorbent polymer filament assemblies like the flame absorption filaments, examples were provided in the absorbent body 56 it is thought.

In the laminated form and the juxtaposed form of these reference examples , even if the fibers are intertwined and integrated as shown in FIG. 4 between the adjacent layers 52A and 52B (or the parts 52D to 52F), As shown in FIG. The former structure can be obtained by opening the adjacent layers 52A, 52B or the portions 52D to 52F through a single passage and blowing the compressed air into the passage and opening them together. When such fiber opening is performed, as the distance between the fibers increases and the bulk increases, the fibers in adjacent layers or portions are entangled and integrated. The latter structure can be obtained by laminating or arranging individually manufactured layers 52A, 52B or portions 52D-52F.

On the other hand, the basis weight of the superabsorbent polymer fiber 55 can be determined as appropriate, and can be, for example, about 30 to 100 g / m ² . If the amount of the superabsorbent polymer fiber 55 used is too small, it is difficult to improve the absorption performance, and if it is too large, the cost effectiveness is lowered.

(Superabsorbent polymer particles)
Preferably, as shown in FIG. 3, superabsorbent polymer particles 54, 54. It is desirable that the superabsorbent polymer particles (SAP particles) 54 are dispersed substantially throughout the thickness direction with respect to the absorber 56 at least in the body fluid receiving region. The state of being substantially dispersed throughout the thickness direction is conceptually shown as an enlarged view of the main part of FIG.

  When there is no SAP particle 54 in the upper part, the lower part, and the middle part of the absorber 56, or there are very few, it cannot be said that it is "dispersed in the whole thickness direction". Therefore, “distributed in the entire thickness direction” means “distributed unevenly in the upper, lower, and / or intermediate portions of the absorber 56 in addition to the form“ uniformly ”distributed in the entire thickness direction. ”Is still dispersed in the upper, lower and middle portions. In addition, a form in which some SAP particles do not enter the absorber 56 and remain on the surface thereof, a form in which some SAP particles fall off the absorber 56 and are on the covering sheet 58, The form on the holding sheet 80 as shown in FIG. 6 is not excluded.

  In some cases, the SAP particles 54 can be unevenly distributed in a part of the absorber 56. In particular, in the laminated form shown in FIG. 4 and FIG. 5, the superabsorbent polymer particles 54 only in one of the layer 52A having the superabsorbent polymer fiber 55 and the layer 52B having the hardly absorbent filament aggregate, for example, only the latter layer 52B. In the side-by-side configuration shown in FIG. 7, only one of the portion 52E having the highly absorbent polymer fiber 55 and the portion 52E, 52F having the hardly absorbent filament aggregate, for example, the latter portions 52E, 52F is high. Absorbent polymer particles 54 can be included.

  Superabsorbent polymer particles mean to include “powder” in addition to “particles”. As the particle diameter of the superabsorbent polymer particles, those used for this type of absorbent article can be used as they are, and those having a particle size of 100 to 1000 μm, particularly 150 to 400 μm are desirable. The material of the superabsorbent polymer particles can be used without any particular limitation, but those having a water absorption of 60 g / g or more are suitable. High-absorbent polymer particles include starch-based, cellulose-based, and synthetic polymer-based starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, and sodium carboxymethylcellulose crosslinks. Or an acrylic acid (salt) polymer can be used. As the shape of the superabsorbent polymer particles, a commonly used granular material is suitable, but other shapes can also be used.

  As the superabsorbent polymer particles, those having a water absorption rate of 40 seconds or less are preferably used. When the water absorption speed exceeds 40 seconds, so-called reversion in which the body fluid supplied into the absorbent body returns to the outside of the absorbent body tends to occur.

  Further, as the superabsorbent polymer particles, those having a gel strength of 1000 Pa or more are preferably used. Thereby, the sticky feeling after body fluid absorption can be suppressed effectively.

The basis weight of the superabsorbent polymer particles can be appropriately determined according to the amount of absorption required for the use of the absorber. Therefore, although it cannot be said unconditionally, it can be set to 50 to 350 g / m ² . By setting the basis weight of the polymer to 50 g / m ² or less, it is possible to prevent the lightening effect from being hardly exhibited due to the weight of the polymer. If it exceeds 350 g / m ² , not only will the effect be saturated, but an excess of superabsorbent polymer particles will give a crisp discomfort when touching the product.

  If necessary, the superabsorbent polymer particles can adjust the spraying density or spraying amount in the plane direction of the absorber 56. For example, the body fluid excretion site can be applied in a larger amount than other sites. When gender differences are taken into account, men can increase the front spray density (amount), while women can increase the center spray density (amount). In addition, a portion where no polymer exists locally (for example, in a spot shape) in the planar direction of the absorber 56 can also be provided.

  If necessary, a plurality of superabsorbent polymer particles having different particle size distributions are prepared, and can be sequentially scattered and projected in the thickness direction on the absorber 56. For example, by disposing the superabsorbent polymer particle spraying means at intervals in the direction of multiple lines, after spraying and projecting the one with the small particle size distribution first, by spraying and projecting the one with the large particle size distribution, A thing with a small particle size distribution can be distributed to the lower side in the absorber 56, and a thing with a large particle size distribution can be distributed to the upper side. This form is effective in order that a thing with a small particle size distribution may penetrate | invade into the absorber 56 deeply.

(Absorber size / weight)
On the other hand, the size of the absorber 56 is preferably such that the planar projection area is 400 cm ² or more and the thickness is 1 to 10 mm, particularly 1 to 5 mm. When the size of the absorber is within this range, it is extremely advantageous to improve the resilience without increasing the weight, thickness and cost. The weight of the absorber is preferably 25 g or less, particularly 10 to 20 g. When the weight of the absorber is within this range, the advantage of not using a dedicated member becomes particularly remarkable.

(Compressive properties of absorber)
The compression resilience RC of the absorbent body 56 is preferably 40 to 60%, particularly 50 to 60%. Thereby, sufficient restoring property can be exhibited with the absorber itself.

Furthermore, it is preferable that the compression energy WC of the absorbent body 56 is 4.0 to 10.0 gf · cm / cm ² , since it can be compressed compactly to the same level as before or during packaging.

  These compression characteristics can be adjusted by adjusting the fiber density by opening or the like, selecting the fiber material, selecting the kind of binder such as a plasticizer, adjusting the degree of processing, or a combination thereof.

  Here, the compression energy (WC) is energy consumption when pressing the central part of the test piece (holding sheet) cut to a length of 200 mm and a width of 50 mm up to 50 g.

This compression energy can be measured with a handy compression tester (KES-G5, manufactured by Kato Tech). The measurement conditions for this tester are: SENS: 2, force meter type: 1 kg, SPEED RANGE: STD, DEF sensitivity: 20, pressurization area: 2 cm ² , capture interval: 0.1 (standard), STROKE SET: 5.0, upper limit load: 50 gf / cm ² .

  On the other hand, the compression resilience (RC) is a parameter representing the recoverability at the time of compression. Therefore, if the recoverability is good, the compression resilience increases. This compression resilience can be measured with a handy compression tester (KES-G5, manufactured by Kato Tech). The measurement conditions for this tester are the same as for the compression energy.

(Enveloping sheet)
As the covering sheet 58, tissue paper, particularly crepe paper, non-woven fabric, polylaminated non-woven fabric, a sheet with small holes, and the like can be used. However, it is desirable that the superabsorbent polymer particles be a sheet that does not escape. When a nonwoven fabric is used in place of the crepe paper, a hydrophilic SMMS (spunbond / meltblown / meltblown / spunbond) nonwoven fabric is particularly suitable, and polypropylene, polyethylene / polypropylene, etc. can be used as the material. The basis weight is preferably 8 to ²⁰ g / m ² , particularly 10 to 15 g / m ² .

  As shown in FIG. 3, the covering sheet 58 may cover only the back and side surfaces of the layer as shown in FIG. Although not shown, only the upper and side surfaces of the absorbent body 56 are covered with crepe paper or nonwoven fabric, and the lower surface is covered with a body fluid-impermeable sheet such as polyethylene, and the upper surface of the absorbent body 56 is covered with crepe paper or nonwoven fabric. For example, the lower surface may be covered with a body fluid impermeable sheet such as polyethylene (each of these materials becomes a component of the covering sheet). If necessary, the absorbent body 56 may be sandwiched between two upper and lower sheets or disposed only on the lower surface, but this is not desirable because it is difficult to prevent the movement of the superabsorbent polymer particles.

(Holding sheet)
The superabsorbent polymer particles 54 can be interposed between the holding sheet 80 and the absorbent body 56 by spraying or the like. The superabsorbent polymer particles 54 may fall off the absorber 56 in the manufacturing process or in the distribution process until use by the consumer. The unevenness of the superabsorbent polymer particles that have fallen off gives a sense of incongruity when touched by the hand when a consumer uses it. Therefore, a holding sheet 80 having a holding performance of the absorbent polymer is interposed between the absorbent body 56 and the covering sheet 58. The holding sheet 80 reinforces the stiffness that is not sufficient only by the covering sheet 58 such as tissue paper (crepe paper), and reduces or prevents a sense of incongruity when touched by the hand when the consumer uses it.

  In FIG. 6, when the superabsorbent polymer particles 54 are provided below the absorber 56, or when the superabsorbent polymer particles 54 contained in the absorber 56 are used from the manufacture to the consumer. In the stage, the case where the absorbent body 56 is pulled out and gathered on the holding sheet 80 is conceptually shown.

  The material of the holding sheet 80 is not particularly limited as long as it has a holding performance of the superabsorbent polymer particles 54. Specifically, non-woven fabric, crimped pulp, low-absorbency cotton fiber (for example, non-degreased cotton fiber, degreased cotton fiber, rayon fiber treated with a water repellent or a hydrophobizing agent, etc.), Examples thereof include polyethylene fiber, polyester fiber, acrylic fiber, polypropylene fiber, silk, cotton, hemp, nylon, polyurethane, and acetate fiber.

If the holding sheet 80 and the nonwoven fabric, its holding sheet 80, the compression energy 0.01~10.00gfcm / cm ² based on KES test, preferably, at 0.01~1.00gfcm / cm ^2, and compressed The non-woven fabric has a resilience of 10 to 100%, preferably 70 to 100%.

  The reason for providing the holding sheet 80 is to hold, for example, the superabsorbent polymer particles 54 that have fallen down (dropped out) from the absorbent body 56 as described above. Therefore, since the superabsorbent polymer particles 54 that have come out come into contact with the user via the covering sheet 58 and the holding sheet 80, there is no possibility of being transmitted to the user as a sense of incongruity. In particular, the holding function is sufficiently exhibited when the nonwoven fabric has the above-described compression energy and compression resilience.

  Further, since the superabsorbent polymer particles 54 that have escaped are held by the holding sheet 80 and do not move on the covering sheet 58, there is no possibility of uneven distribution of absorption capacity. In particular, in order to prevent the superabsorbent polymer particles 54 from moving on the holding sheet 80, an adhesive hot melt adhesive or the like can be applied on the holding sheet 80 in advance. Alternatively, the upper surface of the holding sheet 80 (surface toward the use surface side) may be a rough surface to prevent the superabsorbent polymer particles 54 from moving on the holding sheet 80. Examples of the roughening or fluffing means for this purpose include a non-net surface that is not a net surface during the production of the nonwoven fabric, a marble process, a needle punch process, and a brushing process.

  Even if the holding sheet 80 is provided only below the absorber 56 as shown in FIG. 3 or the like, the holding sheet 80 passes through the side surface of the absorber 56 and extends up to the upper surface of the absorber 56 as shown in FIG. May be. It is also possible to use a plurality of holding sheets 80 in a stacked manner.

  The above example is an example in which the holding sheet 80 is provided between the absorbent body 56 and the back surface side portion of the covering sheet 58, but the holding sheet 80 may be on the back side from the covering sheet 58 (its form) In short, if the holding sheet 80 is provided on the back surface side with respect to the absorbent body 56, it is possible to reduce or not cause a crisp discomfort when touching from the back surface of the product.

(Body fluid impermeable sheet)
The body fluid impermeable sheet 70 simply means a sheet disposed on the back surface side of the absorber 56, and in the present embodiment, is a sheet in which the absorber 56 is interposed between the top sheet 30. Therefore, the material of the main body liquid impermeable sheet is not particularly limited. Specifically, for example, an olefin resin such as polyethylene or polypropylene, a laminated nonwoven fabric obtained by laminating a nonwoven fabric on a polyethylene sheet or the like, a nonwoven fabric that substantially ensures liquid impermeability by interposing a waterproof film (in this case, A body fluid impermeable sheet is comprised with a waterproof film and a nonwoven fabric.) Etc. can be illustrated. Of course, in addition to this, materials having liquid impermeability and moisture permeability, which have been used and used in recent years from the viewpoint of preventing stuffiness, can also be exemplified. As the sheet of the material having liquid impermeability and moisture permeability, for example, an inorganic filler is kneaded in an olefin resin such as polyethylene or polypropylene, and the sheet is formed, and then stretched in a uniaxial or biaxial direction. Examples of the microporous sheet obtained in this way can be given.

  The body fluid impervious sheet 70 can be prevented from side leakage of body fluid by extending it to the use surface in a so-called forehead form (not shown). This is prevented by interposing a second body fluid impermeable sheet 72 between the double barrier sheets 64 forming 60. According to this embodiment, since the second body fluid impermeable sheet 72 extends until the barrier cuff 60 stands up, the body fluid diffused laterally through the top sheet 30 and the side of the soft stool between the barrier cuffs 60, 60 There is also an advantage that leakage can be prevented.

(Barrier cuffs)
Barrier cuffs 60, 60 provided on both sides of the product are provided to prevent urine and soft stool that travel laterally along the top sheet 30 and prevent side leakage. It is.

  The illustrated barrier cuff 60 is a doubled water-repellent non-woven sheet, and is formed so as to protrude from the back side of the absorbent body 56 to the lower side of the top sheet 30 and to protrude to the front side. Yes. In order to prevent urine moving in the lateral direction along the top sheet 30, in particular, the side part of the body fluid impermeable sheet 70 is inserted between the double nonwoven fabric sheets, and the barrier cuff 60 protruding from the surface side is provided. It extends halfway.

  The shape of the barrier cuff 60 itself can be designed as appropriate. However, in the example shown in the drawing, an elastic elastic member, for example, a rubber thread 62 is fixed to the tip and middle of the protruding portion of the barrier cuff 60 under stretch, The barrier cuff 60 stands up due to the contraction force in use. As shown in FIG. 3, the base side of the barrier cuff 60 is positioned so that the middle rubber thread 62 is positioned at the center side of the front rubber thread 62, 62 and fixed to the front and rear end portions of the top sheet 30. It rises diagonally toward the center side, and the tip part stands up diagonally outward from the intermediate part.

(Embossing)
You may form the recessed part E by embossing from the surface side of the top sheet 30 to the thickness direction. In this case, the embossed recess E is formed only on the top sheet 30, and the embossed recess E is formed on both the top sheet 30 and the intermediate sheet 40 as shown in FIG. A concave portion by embossing can be formed (not shown) so as to reach a part or substantially the entire thickness direction of the absorber 56 from the side. In order to form the recess E by embossing in both the top sheet 30 and the intermediate sheet 40, the intermediate sheet 40 has a basis weight of 8 to 40 g / m ² , a thickness of 0.2 to 1.5 mm, and a top sheet. As for 30, it is desirable that the basis weight is in the range of 15 to 80 g / m ² and the thickness is in the range of 0.2 to 3.5 mm in that embossing can be sufficiently performed under the condition that liquid permeability is not impaired.

  Moreover, you may form the recessed part by embossing only in the intermediate sheet 40, without forming a recessed part in the top sheet 30, and also emboss only in the absorption element 56, without forming a recessed part in the top sheet 30 and the intermediate sheet 40. In addition, the embossed recess may be formed only in the absorbent body 58 without forming the recess in the top sheet 30, the intermediate sheet 40, and the covering sheet 58.

  The recess E has an effect of inducing and diffusing body fluid in the direction in which the recess E extends. Therefore, when the recesses E are substantially continuous in a groove shape (including the case where a plurality of recesses are arranged at intervals and form a single groove), the body fluid reaches the absorber before reaching the absorber. It becomes diffused along the recess E, so that a wider part of the absorber can be used for absorption. Therefore, the absorbent capacity of the entire product is increased, and the absorbent article is less likely to cause side leakage or reversal due to insufficient absorbent capacity.

  On the other hand, the absorber 56 made of tow is liable to be less rigid than a conventional pulp product, but it is preferable to form a recess by embossing in the absorber 56 because the rigidity can be increased. Although not shown, in order to increase the rigidity of the absorbent element 50, it is also a preferred form to form a concave portion by embossing in the thickness direction from the back surface side (the side opposite to the top sheet 30 side) of the absorbent body 56. In order to form the concave portion on the back surface side, embossing is integrally performed so as to reach the absorber 56 from the back surface side of the holding sheet 80, the covering sheet 58, the body fluid impermeable sheet 70 or the exterior sheet 12. Can do. Moreover, it is preferable to form such a concave portion on the back surface side together with the concave portion E on the front surface side, but it is also possible to form only the concave portion on the back surface side without forming the concave portion E on the front surface side. When the concave portions are provided on both the front and back sides, the shape of the concave portions may be common to the front and back sides, or may be different from each other.

  The embossed recess has the effect of inducing and diffusing body fluid in the extending direction. It also has the effect of increasing rigidity. Therefore, it is desirable to determine the shape of the embossed recess in consideration of these effects. For example, the recesses are substantially continuous in the shape of a groove (including the case where a plurality of recesses are arranged in a row and form a single groove), and the plurality of recesses are arranged in a dotted pattern at intervals. It may be. In addition, as the planar pattern, groove-shaped or dot-shaped concave portions are arranged in the longitudinal direction, the width direction, a lattice shape combining these, a zigzag shape (zigzag shape) reciprocating in the width direction, or irregularly arranged. Forms can be taken. Furthermore, appropriate forms such as a pin shape, a Mt. Fuji shape, and a bellows shape can be adopted.

(Other)
In addition, although not shown in figure, each structural member of the absorptive main body 20 can be mutually fixed by solid, beads, spiral application, etc., such as a hot-melt-adhesive.

(Example of tape-type disposable diapers)
8 and 9 show examples of tape-type disposable diapers. 9 is a view taken along line 9-9 in FIG. 8, but the absorbent main body 20 is illustrated in a slightly exaggerated manner.

  The tape-type disposable diaper 10A has fastening pieces attached to both end portions on the back side of the diaper, has a hook element on a fastening surface of the fastening piece, and a back sheet constituting the back side of the diaper is laminated with a nonwoven fabric. The diaper is configured to be able to engage with a hook element of the fastening piece at an arbitrary position on the surface of the back sheet when the diaper is used as a body.

  The absorbent main body 20 has an absorbent body 56 interposed between the top sheet 30 and the body fluid impermeable sheet 70. The absorbent body 56 is entirely wrapped by a covering sheet 58, and has a rectangular shape in plan view. A holding sheet 80 is provided between the absorber 56 and the covering sheet 58.

  Further, an intermediate sheet 40 is interposed between the top sheet 30 and the absorber 56. The body fluid impermeable sheet 70 has a rectangular shape wider than the absorbent body 56, and a back sheet 12A made of an hourglass-shaped non-woven fabric is provided on the outer side thereof.

  The top sheet 30 has a rectangular shape wider than the absorbent body 56, extends slightly outward from the side edge of the absorbent body 56, and is fixed to the body fluid impermeable sheet 70 with a hot melt adhesive or the like.

  Barrier cuffs 60A projecting to the use surface side are formed on both sides of the diaper. The barrier cuffs 60A are formed of a barrier sheet 64 made of a nonwoven fabric substantially continuous in the width direction, and an elastic elastic member such as a thread rubber. And one or a plurality of leg rubber elastic members 62 as elastic elastic members for the leg periphery. 130 is a fastening piece by a hook-and-loop fastener.

  The inner surface of the barrier sheet 64 has a fixing start edge at a position separated from the side edge of the top sheet 30, and the outer portion in the width direction extends from the fixing start edge to the extending edge of the body fluid impermeable sheet 70. It is fixed by. The outer surface of the barrier sheet 64 is fixed to the back sheet 12A with a hot melt adhesive or the like on the lower surface thereof. Further, an elastic expansion / contraction member for gasket cuff, for example, thread rubber 66 is provided.

  The starting end of the inner surface of the barrier sheet 64 fixed to the body fluid impermeable sheet 70 forms an upstanding end of the barrier cuff 60A. Around the leg, the inside of the standing end is a free part that is not fixed to the product body, and this free part comes to stand by the contraction force of the rubber thread 62.

  In this example, by using a hook-and-loop fastener as the fastening piece 130, it can be mechanically fastened to the backsheet 12A. Therefore, a so-called target tape can be omitted, and a fastening position by the fastening piece 130 can be freely selected.

  The fastening piece 130 has a base portion of a fastening base material made of plastic, polylaminated nonwoven fabric, paper, or the like joined to the back sheet 12A, for example, with an adhesive, and has a hook element 130A on the tip side. The hook element 130A is bonded to the fastening substrate with an adhesive. The hook element 130A has a large number of engaging pieces on the outer surface side thereof. A temporary fixing adhesive portion 130B is provided on the tip side from the hook element 130A. At the end of the assembly of the product, the temporary fixing adhesive portion 130B is adhered to the barrier sheet 64, thereby preventing the fastening piece 130 from being peeled off at the front end side. At the time of use, it peels off against the adhesive force and brings the front end of the fastening piece 130 to the front body. The fastening base material is exposed at the tip side of the temporary fixing adhesive portion 130B, and is a tab portion.

  A target printing sheet 74 as a design sheet is provided on the inner surface side of the back sheet 12A on the opening side of the front body, and a design that serves as a guide for the position at which the hook element 130A of the fastening piece 130 is fastened is applied. Target printing is performed so that the target can be visually recognized through the back sheet 12A.

  When the diaper is mounted, the diaper is mounted on the body in the shape of a boat, and the contraction force of the rubber thread 62 acts. Therefore, the barrier cuff 60A stands up around the leg by the contraction force of the rubber thread 62.

  The space surrounded by the standing part forms a confined space for urine or soft stool. When urinating into this space, the urine is absorbed into the absorbent body 56 through the top sheet 30, and the rising part of the barrier cuff 60A becomes a barrier for the solid matter of soft stool, and the overpass is prevented. The In the unlikely event that urine leaks laterally over the standing distal side edge of the standing part, side leakage is prevented by the stop function by the flat contact part.

In this embodiment, it is desirable that the barrier sheet 64 forming each standing cuff is not liquid-permeable but substantially liquid-impervious (may be semi-liquid-permeable). Further, the surface sheet (nonwoven fabric laminate) of the present invention may have a property of repelling liquid by silicon treatment or the like. In any case, it is preferable that the barrier sheet 64 and the back sheet 12A are air permeable, and the barrier sheet 64 and the back sheet 12A are sheets having a water pressure resistance of 100 mmH ₂ O or more. Thereby, it becomes air permeable in the width direction side part of a product, and a wearer's stuffiness can be prevented.

  The other points, for example, the material used for each part, etc. are the same as in the case of the above-described pants-type paper diaper, and therefore the description is omitted.

  The present invention is suitable for absorbent articles such as paper diapers, sanitary napkins, incontinence pads, and absorbent pads used in combination with diaper covers.

It is a perspective view of a pants-type disposable diaper. It is an expanded state top view of a pants type disposable diaper. FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. 2. It is sectional drawing of another example. It is sectional drawing of another example. It is sectional drawing of another example. It is sectional drawing of another example. It is an expanded state top view of a tape type disposable diaper. FIG. 9 is a sectional view taken along line 9-9 in FIG. 8.

  DESCRIPTION OF SYMBOLS 10 ... Pants type disposable diaper, 10A ... Tape type disposable diaper, 12 ... Exterior sheet, 12A ... Back sheet, 20 ... Absorbent main body, 30 ... Top sheet, 40 ... Intermediate sheet, 50 ... Absorbing element, 52 ... Difficult absorption filament 52X ... Veil, 52Y ... Toe, 52Z ... Filament assembly, 54 ... Super absorbent polymer particles, 55 ... Super absorbent polymer fiber, 56 ... Absorber, 58 ... Cover sheet, 60, 60A ... Barrier cuff, 64 ... Barrier sheet, 70 ... Body fluid impermeable sheet, 72 ... Second body fluid impermeable sheet, 80 ... Holding sheet, E ... Heat fusion part.

Claims (4)

A top sheet that allows body fluid to permeate, a body fluid impermeable sheet, and an absorbent element provided therebetween,
In the absorbent article , the absorbent element includes an absorbent body and a covering sheet that wraps at least the back and side surfaces of the absorbent body .
The absorber, possess a 1.0-fold following flame absorbent filament aggregate of the artificial urine absorption of its own weight, and superabsorbent polymer fibers,
The difficult-to-absorb filament assembly is formed by opening 3,000-1,000,000 bundled crimped cellulose ester filaments having a fineness of 1-16 dtex,
The high absorption polymer fiber is a short fiber having a water absorption of 30 times or more of its own weight and a fineness of 1.0 to 20 denier,
The superabsorbent polymer fiber is dispersed and mixed in the whole or a part of the aggregate of the hardly absorbent filaments,
The basis weight of the superabsorbent polymer fiber is 30 to 100 g / m ² ;
An absorbent article characterized by the above. The absorbent article according to claim 1, wherein superabsorbent polymer particles are dispersed throughout the thickness direction of the absorber. Compression energy based on KES test is 0.01-10.00 gfcm / cm ² And a holding sheet having a holding function and a stiffness reinforcing function of the superabsorbent polymer particles that have come out of the filament aggregate and have a compression resilience of 10 to 100%. The absorptive article according to claim 2 provided between back side parts. The absorptive article according to any one of claims 1 to 3 which is a disposable diaper.

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