JP4969101B2 - Method for manufacturing absorbent article - Google Patents

Description

The present invention relates to a method for manufacturing an absorbent article .

Absorbent articles such as infant and adult tape-type and pants-type disposable diapers and sanitary napkins are used on the top sheet on the use side, the back sheet that prevents the permeation of liquid on the back side, and interposed between these sheets The basic element is an absorption element that receives and holds the excreted liquid that has permeated 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 liquid that has permeated through the top sheet on the use surface side, conventionally, a fiber stack of pulp short fibers has been generally used. It is also known to use superabsorbent polymer particles (hereinafter also referred to as “SAP”) to increase the amount of absorption in the liquid.
In addition to the case where the SAP is dispersed on the piled fiber of short pulp fibers, there are cases 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 the tow as a liquid acquisition layer, i.e. an absorbent element. In this absorbent element, the filament constituting the tow extends to the front and rear ends of the absorbent element along the front-rear direction.
JP 2004-65300 A Japanese translation of PCT publication No. 2002-508218 (WO99 / 27879)

However, in an absorbent element using a filament aggregate in which hardly absorbable filaments that hardly absorb water per se, such as cellulose acetate tow, are gathered in a bundle, the liquid easily diffuses along the continuous direction of the filaments, and the filament If the both ends of the liquid crystal extend to the periphery of the absorbent element, leakage may occur due to the rapid supply of a large amount of liquid to the end.
Then, the main subject of this invention is preventing the leak resulting from the excessive supply of the liquid with respect to the edge part of an absorption element.

  The present invention that has solved the above problems is as follows.

<Invention of Claim 1 >
It has an absorption element that absorbs liquid that has passed through the top sheet on the use surface side
The absorbent element has a lower layer absorber and an upper layer absorber provided on the top sheet side,
The lower layer absorbent is composed of an aggregate of pulp fibers or filaments and superabsorbent polymer particles, and is wrapped in a covering sheet,
The upper-layer absorber is obtained by opening a tow, and sticking a hardly absorbable filament aggregate having an absorption amount of 1.0 times or less of its own weight to a liquid-permeable sheet different from the covering sheet, or The filament aggregate is wrapped with a liquid permeable sheet different from the enveloping sheet, and the filament extends along the top sheet, and both ends of the filament are inside from the periphery of the lower layer absorbent body. 10 to 300 mm apart,
A method for producing an absorbent article characterized by comprising:
In manufacturing the absorbent element,
While producing the lower layer absorbent body by wrapping an aggregate of pulp fibers or filaments and superabsorbent polymer particles in a covering sheet,
A difficult-to-absorb filament assembly obtained by opening a tow and having an absorption amount of 1.0 times or less of its own weight is attached to a liquid-permeable sheet different from the envelope sheet, or the envelope sheet After wrapping with another liquid-permeable sheet, the upper absorbent body is manufactured by cutting at a predetermined interval in the continuous direction of the hardly absorbent filament,
The upper layer absorbent body, as both ends of the filament 10~300mm spaced inwardly from the periphery of the lower absorbent body, predetermined upper pulp fibers or filaments aggregate of the top of the lower absorbent body or the lower absorbent body The manufacturing method of the absorbent article characterized by sticking to a position.
(Function and effect)
A filament aggregate obtained by opening a tow is a material that is difficult to handle in manufacturing because it is likely to be broken or out of shape. For this reason, in the manufacture of conventional absorbers, the filament aggregates are handled in a continuous state, and the filament aggregates are also cut using cutting into individual absorbers.
However, in such a manufacturing method, only the absorbent body in which both ends of the filament extend to the periphery of the absorbent element can be manufactured, and the above-described leakage problem cannot be avoided. For this reason, development of the manufacturing technique which can arrange | position the aggregate | assembly of a filament in the desired position in an absorber was desired.
The present invention has been made in view of such problems. In the present invention, prior to cutting, the continuous filament aggregate is attached to the continuous liquid-permeable sheet or wrapped with the liquid-permeable sheet, so that the filament aggregate is scattered or lost its shape. It becomes difficult to do. For filament aggregates integrated with the sheet, a sheet processing device such as a slip cutter can be used, and the filament aggregate is placed in a desired position in the absorbent body without requiring special equipment. Can be placed in.
On the other hand, in the absorbent article manufactured according to the present invention, both ends of the filament are spaced inward from the peripheral edge of the absorbent element. Can stop the diffusion. Accordingly, excessive supply of liquid to the end portion of the absorbing element is suppressed, and leakage prevention is achieved.
The absorption amount of 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, remove the sample from the artificial urine and suspend it 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 amount of absorption.
Further, in this absorbent article, even if the liquid component supplied to the upper layer absorbent passes through the upper layer absorbent body and reaches both ends of the filament, the liquid stops diffusing there and does not diffuse to the periphery of the absorbent element. Then, the liquid component diffused in the upper layer absorbent body is transferred to and held by the lower layer absorbent body. Accordingly, excessive supply of liquid to the end portion of the absorbing element is suppressed, and leakage prevention is achieved.
In addition, when the distance between the filament ends and the peripheral edge of the lower layer absorber is within the above range, the above-described leakage prevention effect is excellent without impairing other performances. If the separation distance is too short, the effect of preventing leakage will be poor, and if it is too long, the diffusion distance by the upper-layer absorber will be short, and the diffusion performance may be poor.

<Invention of Claim 2 >
A step of affixing the liquid permeable sheet to the hardly absorbent filament aggregate, a step of intermittently spraying and projecting highly absorbent polymer particles on the hardly absorbent filament aggregate, and a step of cutting an intermittent portion of the absorbent polymer particles, a manufacturing method of an absorbent article according to claim 1.

  As described above, according to the present invention, it is possible to suppress the excessive supply of the liquid to the edge portion of the absorption element, and to bring about advantages such as prevention of leakage.

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 outer surface (back surface) side exterior sheet 12 and an inner surface (front surface) side interior body 20, and the interior body 20 is fixed to the exterior sheet 12. The interior body 20 is a part that receives and absorbs and retains liquid such as urine and loose stool (menstrual blood in the case of a sanitary napkin described later). The exterior sheet 12 is a part for mounting on the wearer.

(Exterior sheet)
The exterior sheet 12 includes a trunk periphery 12T that is defined as a front-rear direction range extending from the trunk opening WO to the upper end of the leg opening LO, and an intermediate portion 12L that is defined as a front-rear direction range of a portion that forms the leg opening LO. The trunk periphery 12T can be conceptually divided into a “trunk upper end” 12W and a “trunk lower” 12U. These lengths in the front-rear direction vary depending on the size of the product, and can be determined as appropriate. For example, the upper part 12W of the waistline can be 15 to 40 mm, and the lower part 12U of the waistline can be 65 to 120 mm. . On the other hand, both side edges of the intermediate portion 12L are constricted along the circumference of the wearer's leg, and this is a portion into which the wearer's leg is placed. As a result, the exterior sheet 12 has a substantially hourglass shape as a whole. In the illustrated example, the width of the exterior sheet 12 in the crotch portion is shorter than that of the interior body 20, but this width relationship may be reversed or the same width.

  As shown in FIG. 2, the exterior sheet 12 is folded back and forth after the interior body 20 is installed and fixed at a predetermined position, and joining regions 12A on both sides of the front body 12F and the back body 12B of the exterior sheet 12 are formed. 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.

The exterior sheet 12 may be formed of a single sheet, but is preferably formed of a two-layer sheet in which an outer layer and an inner layer are bonded together with an adhesive such as a hot melt adhesive. The outer layer and the inner layer can be used without any particular limitation, but it is preferable to use a water-repellent nonwoven fabric from the viewpoint of touch and waterproofness. Each of the outer layer and the inner layer may be formed by laminating a plurality of materials. Although the thicknesses of the outer layer and the inner layer can be determined as appropriate, the thickness of the outer layer is preferably equal to or greater than the thickness of the inner layer. The outer layer and the inner layer are each preferably in the range of 5 to 30 g / m ^{2 in} basis weight. Further, the thickness of the outer layer 12S is preferably 5 mm or less, and the thickness of the inner layer is preferably 1 mm or less.

  Elastic stretch members 12C and 12D are fixed to the exterior sheet 12 with a hot melt adhesive or the like in an extended state. The elastic elastic members 12C and 12D can be used without particular limitation as long as they are elongated rubber materials such as a thread shape, a string shape, and a belt shape.

  More specifically, a large number of waist elastic elastic members 12C extending along the width direction between the outer layer and the inner layer in the waist lower portion 12U of the exterior sheet 12 with a predetermined interval in the front-rear direction, for example, About 15 to 40 are provided in parallel.

  As shown in FIG. 1, by cutting the waist elastic elastic member 12 </ b> C by embossing, needle sticking, or the like in a portion overlapping the interior body 20, or by not providing the waist elastic elastic member 12 </ b> C in a portion overlapping the interior body 20, The contractile force can be eliminated or weakened. In the case of cutting, as disclosed in Japanese Patent Application Laid-Open No. 2002-178428, a plurality of points may be cut at predetermined intervals in the width direction, or only one point may be cut. Thus, if the elastic elastic member 12C is discontinuous in the portion overlapping with the interior body 20 (either part or all), the contraction force acting on the interior body 20 is lost or weakened, Absorption inhibition due to shrinkage of the interior body 20 is less likely to occur. The width of the cut or missing portion of the elastic elastic member 12C can be determined as appropriate. Further, unlike the illustrated embodiment, the waist elastic elastic member 12C can be made discontinuous only in either the back side B or the ventral side F.

  The thickness and arrangement interval of the waist elastic elastic member 12C can be determined as appropriate, but preferably the thickness is 1000 dtex or less, particularly 700 to 400 dtex, and the arrangement interval is 1 to 20 mm, particularly 1 to 10 mm.

  On the other hand, at the upper end U around the trunk of the exterior sheet 12, the outer layer is folded inside the exterior sheet 12 at the trunk opening WO, and is parallel to the edge of the trunk opening WO between the folded portion and the exterior sheet 12. The body end elastic elastic member 12D is fixed in an extended state with a gap therebetween. The thickness, interval, and number of the trunk end elastic members 12D can be determined as appropriate. For example, the thickness is preferably 400 to 900 dtex, the interval is 3 to 6 mm, and the number is preferably about 4 to 10.

(Interior body)
As shown in FIG. 3, the interior body 20 includes a liquid-permeable top sheet 30, a liquid-impermeable sheet (also referred to as a back sheet) 70, and an absorbent element 50 interposed therebetween. Yes. The exterior sheet 12 described above is provided on the back side of the liquid-impermeable sheet 70. Further, barrier cuffs 60, 60 projecting toward the use surface side are provided on both sides of the interior body 20.

(Top sheet)
The top sheet 30 can be formed using a liquid-permeable material. For example, a porous or non-porous nonwoven fabric, a porous plastic sheet, or the like can be used. Non-woven fabric is not limited by the raw fiber, 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, etc. A mixed fiber, a composite fiber, or the like in which two or more of these are used can be used. Further, the nonwoven fabric is not limited by the production method, and is produced by, for example, a known method such as a spunlace method, a spunbond method, a thermal bond method, a melt blown method, a needle punch method, an air through method, or a point bond method. Things can be used. Of these, the spunlace method is preferable if flexibility and drapeability are required, and the thermal bond method is a preferable processing method if bulkiness and softness are required.

  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.

(Liquid impervious sheet)
The liquid impermeable sheet 70 is a sheet disposed on the back side of the absorber 56. The material of the liquid-impermeable sheet is not particularly limited, but for example, an olefinic resin such as polyethylene or polypropylene, a laminated nonwoven fabric in which a nonwoven fabric is laminated on a polyethylene sheet, or the like, and a waterproof film are substantially interposed. A non-woven fabric ensuring liquid impermeability (in this case, a liquid impervious sheet is composed of a waterproof film and a non-woven fabric) can be used. 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.

(Absorption element)
The absorbent element 50 includes a lower layer absorbent body 56B and an upper layer absorbent body 56A provided on the top sheet 30 side. Among these, the upper layer absorbent body 56A is obtained by opening the tow and absorbs the amount. Is formed of an aggregate of hardly absorbing filaments 52 that is 1.0 times or less of its own weight. The filament 52 of the upper layer absorbent body 56A extends along the top sheet 30 in the front-rear direction in the illustrated form, and as shown in FIG. 2, both ends (tip and base end) of the filament 52 are absorbed by the lower layer. It is spaced inward from the front and rear edges (periphery of the absorbent element 50) of the body 56B.

  In this case, even if the liquid component supplied to the upper layer absorbent body 56 </ b> A passes through the upper layer absorbent body 56 </ b> A and reaches both ends of the filament, the diffusion of the liquid stops there and does not diffuse to the periphery of the absorbent element 50. Then, the liquid component diffused in the upper layer absorbent body 56A moves to and is held in the lower layer absorbent body 56B.

  The separation distance y between the both ends of the filament 52 (the front edge and the rear edge of the upper layer absorbent body 56A) and the front edge and the rear edge of the lower layer absorbent body 56B is different depending on the subject wearer. It is desirable that it is 10-300 mm, especially 50-150 mm. If the separation distance y is too short, the effect of preventing leakage will be poor, and if it is too long, the diffusion distance by the upper absorbent body 56A will be short, and the diffusion performance may be poor.

  Moreover, it is desirable that the upper layer absorbent body 56A is separated from both side edges of the lower layer absorbent body 56B not only at both ends of the filament 52 but also at both side edges. The separation distance x varies depending on the target wearer and cannot be generally specified, but is preferably 0 to 90 mm, particularly preferably 0 to 50 mm.

  The size of the lower layer absorber 56B is preferably 200 to 600 mm in the front and back length and 100 to 180 mm in width, and the size of the upper layer absorber 56A is 100 to 500 mm in the front and back length and 50 to 120 mm in width. Is preferred.

  The aggregate of the filaments 52 constituting the upper layer absorbent body 56A is a bundle-like aggregate and easily breaks up or loses its shape. Therefore, in order to facilitate handling in manufacturing, as shown in FIG. 3, the liquid permeable sheet 40 is attached to the side surface of the top sheet 30 of the upper layer absorbent body 56A using a hot-melt adhesive or the like. As shown in FIG. 5, the entire periphery (front and back and both sides) of the upper layer absorbent body 56A is integrally wrapped with the liquid permeable sheet 40, or the liquid permeable sheet 41 is formed on the back surface of the upper layer absorbent body 56A as shown in FIG. Is preferably pasted using a hot melt adhesive or the like. In the case of the former two, a part or all of the liquid-permeable sheet 40 can be an intermediate sheet described later. In any case, an intermediate sheet can be separately provided between the top sheet 30 and the upper layer absorbent body 56A.

  The hardly absorbent filament aggregate constituting the upper layer absorbent body 56A can be produced by opening a tow (fiber bundle) composed of hardly absorbent filaments (substantially continuous long fibers). The filament 52 can extend along any direction, such as the longitudinal, width, or thickness direction of the article.

  The material of the hardly absorbable filament 52 can be used without particular limitation as long as the amount of absorption is 1.0 times or less of its own weight. For example, polysaccharides or derivatives thereof (cellulose, cellulose ester, chitin, chitosan, etc.), synthesis Polymers (polyethylene, polypropylene, polyamide, polyester, polylactamamide, polyvinyl acetate, etc.) can be used, and cellulose esters and cellulose are particularly preferable.

  As cellulose, cellulose derived from plants such as cotton, linter, and wood pulp, bacterial cellulose, and the like can be used. Regenerated cellulose such as rayon may be used, and the regenerated cellulose may be spun.

  Examples of cellulose esters 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 absorbed amount 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, for example, 1 to 16 dtex, preferably 1 to 10 dtex, and more preferably 1 to 5 dtex. The filament may be a non-crimped fiber, but is preferably a crimped fiber. 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. . For example, 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. . The fiber bundle is preferably formed by concentrating about 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, no detailed description will be given. 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 tow is spread over a plurality of opening rolls, and the tow width is gradually expanded as the tow progresses, and tow tension (elongation) and relaxation (shrinkage) And the like, and a method of widening and opening using compressed air can be used.

  The upper absorbent body 56A preferably does not contain superabsorbent polymer particles, but can also be contained. Details of the superabsorbent polymer particles will be described later.

  On the other hand, the lower layer absorbent body 56B is a general-purpose absorbent body formed by mixing pulp fibers 55 and superabsorbent polymer particles 54 and stacking them in a cotton form. The lower layer absorbent body 56B can be rectangular like the upper layer absorbent body. However, as shown in the figure, the lower layer absorbent body 56B may have an hourglass shape in which both sides of the crotch portion are cut out in an arc shape around the legs. it can.

  The superabsorbent polymer particles 54 include “powder” in addition to “particles”. The particle diameter of the superabsorbent polymer particles 54 is not particularly limited, but is preferably 100 to 1000 μm, particularly preferably 150 to 400 μm. The water absorption amount of the superabsorbent polymer particles 54 is not particularly limited, but is preferably 40 g / g or more. Examples of the superabsorbent polymer particles 54 include starch-based, cellulose-based and synthetic polymer-based polymers, such as starch-acrylic acid (salt) graft copolymer, saponified starch-acrylonitrile copolymer, and sodium carboxymethylcellulose. A cross-linked product or an acrylic acid (salt) polymer can be used. The shape of the superabsorbent polymer particles 54 is preferably a granular material that is usually used, but other shapes can also be used.

  As the superabsorbent polymer particles 54, those having a water absorption speed of 40 seconds or less are preferably used. When the water absorption speed exceeds 40 seconds, so-called reversal that the liquid supplied into the absorber 56 returns to the outside of the absorber is likely to occur. Moreover, as the superabsorbent polymer particles 54, those having a gel strength of 1000 Pa or more are preferably used. Thereby, the sticky feeling after liquid absorption can be suppressed effectively.

The basis weight of the superabsorbent polymer particles 54 in the lower layer absorbent body 56B can be appropriately determined according to the amount of absorption required for the use of the absorbent body. 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 superabsorbent polymer particles 54 to be 50 g / m ² or less, it is possible to prevent the weight-reducing effect from being hardly exhibited due to the weight of the superabsorbent polymer particles 54. If it exceeds 350 g / m ² , not only will the effect be saturated, but the excess of the superabsorbent polymer particles 54 will give a crisp discomfort when touching the product.

  If necessary, the superabsorbent polymer particles 54 can be adjusted in density or amount in the plane direction of the lower layer absorber 56B. For example, a larger amount of superabsorbent polymer particles 54 can be present at the excretion site than at other sites. When gender differences are taken into account, men can increase the density (amount) on the front side, and women can increase the density (amount) in the center. In addition, a portion where the superabsorbent polymer particles 54 do not exist locally (for example, in a spot shape) in the planar direction of the lower layer absorbent body 56B can be provided.

(Enveloping sheet)
When the superabsorbent polymer particles 54 are contained in the lower layer absorbent body 56 </ b> B, it is preferably wrapped with a covering sheet 58. The same applies to the case where the superabsorbent polymer particles 54 are contained in the upper layer absorbent body 56A. This covering sheet 58 is also a component of the absorbent element 50.

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 instead 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 can adopt a form in which only the lower layer absorbent body 56 </ b> B is wrapped, and a form in which the upper layer absorbent body 56 </ b> A and the lower layer absorbent body 56 </ b> B are wrapped together as shown in FIG. 6. Further, it is desirable that the covering sheet 58 wraps the entire object as shown in FIG. 3, but it is also possible to cover only the back and side surfaces of the object (not shown).

(Intermediate sheet)
An intermediate sheet (also referred to as a “second sheet”) having a higher liquid permeation rate than the top sheet 30 so as to be in direct contact with the back surface of the top sheet 30 in order to quickly transfer the liquid that has passed through the top sheet 30 to the absorber 56A. ) 40 can be provided. This intermediate sheet 40 is also a constituent element of the absorbent element 50. The intermediate sheet 40 not only improves the absorption performance by quickly transferring the liquid to the upper layer absorbent body 56A, but also prevents the “returning” phenomenon of the absorbed liquid.

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

  The intermediate sheet (second sheet) 40 is disposed so as to contact the back surface of the top sheet 30. The intermediate sheet (second sheet) 40 may not be provided.

  The intermediate sheet 40 is preferably arranged in the center and narrower than the width of the absorbent element 50 as illustrated, but may be provided over the entire width of the absorbent element 50. The length in the front-rear direction of the intermediate sheet 40 may be the same as the length of the absorbent element 50, or may be within a short length range centered on the excretory part. In particular, the width and length of the intermediate sheet 40 are preferably the same as the width and length of the upper absorbent body 56A.

(Holding sheet)
When the superabsorbent polymer particles 54 are used as the absorbent element 50, as shown in FIG. 6 and FIG. 8, the lower side absorber 56B or A holding sheet 80 can be provided between the back surface of the absorbent body 56 and the back surface side portion (lower portion) of the covering sheet 58. This holding sheet 80 is also a component of the absorbent element 50. The holding sheet 80 is not an essential component and therefore may not be provided.

  The superabsorbent polymer particles 54 may move in the manufacturing process or in the distribution process until use by the consumer. For example, when the superabsorbent polymer particles 54 are mixed in the lower layer absorber 56B, the superabsorbent polymer particles 54 may fall out of the lower layer absorber 56B. 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. With respect to this problem, if the holding sheet 80 having the holding performance of the absorbent polymer is interposed on the back side of the portion where the superabsorbent polymer particles 54 are disposed, the stiffness that is not sufficient only by the covering sheet 58 is reinforced. To reduce or prevent a sense of discomfort when the consumer touches it when using it.

  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 absorber 56. 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.

  The holding sheet 80 may be provided only under the absorber 56 as shown in FIG. 6 or the like, or may be wound up and extended to the upper surface of the absorber 56 through the side surface of the absorber 56, although not shown. . 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.

  When the holding sheet 80 is provided between the absorbent body 56 and the liquid-impermeable sheet 70, a fiber aggregate having a larger amount of absorption than the hardly absorbent filament aggregate, for example, a fiber aggregate having an absorption amount of about 5 to 30 times. When the holding sheet 80 is formed using the holding sheet 80, the water absorption performance of the absorbent body 56 can be supplemented by the holding sheet 80, and the initial absorption rate and diffusibility can be improved. Can be made.

(Other absorbent element forms)
The lower absorbent body 56B of the absorbent element 50 is preferably a mixed fiber of the pulp fibers 55 and the superabsorbent polymer particles 54 as in the above example, but the assembly of hardly absorbent filaments 52 similar to the upper absorbent body 56A. The body can also contain superabsorbent polymer particles 54. In this case, it is desirable that the superabsorbent polymer particles 54 are dispersed substantially throughout the thickness direction with respect to the aggregate of filaments 52. The state of being substantially dispersed throughout the thickness direction is conceptually shown in the enlarged view of the main part in FIG. In addition, when the superabsorbent polymer particles 54 are not present in the upper part, the lower part, and the middle part of the filament aggregate, or there are very few, it cannot be said that the filaments are dispersed throughout the thickness direction. Therefore, “distributed in the entire thickness direction” means “distributed unevenly in the upper, lower, and / or middle portions of the filament aggregate in addition to the form“ uniformly ”distributed in the entire thickness direction. ”Is still dispersed in the upper, lower and middle portions. Also, a form in which some superabsorbent polymer particles 54 remain on the surface of the filament aggregate, or a form in which some superabsorbent polymer particles 54 fall off the filament aggregate and are on the covering sheet 58 is retained. The form on the sheet 80 is not excluded.

  Moreover, the absorption element 50 is good also as a structure which has an absorber of three or more layers although not shown in figure. In this case, it is preferable that one or a plurality of absorbers positioned on the top sheet 30 side is formed of the above-described hardly absorbent filament aggregate.

  When a plurality of absorbers are laminated as the absorbent element 50, all of them may have the same material configuration, or any one or a plurality of layers may have a different material configuration with respect to the other layers. Moreover, it is preferable not to have a layer which consists only of superabsorbent polymer particles irrespective of the number of layers.

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

  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 enhance the leak-proof property, the second liquid-impermeable sheet 72 is inserted between the double nonwoven fabric sheets, and extends to the middle of the barrier cuff 60 protruding to the surface side.

  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)
As shown in FIG. 7, you may form the recessed parts E and F 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 although not shown, the embossed recess is formed only on both the top sheet 30 and the intermediate sheet 40, as shown in FIGS. 3 and 7. As described above, the embossed recess F can be formed so as to reach a part or substantially the entire thickness of the absorber 56A (or 56B) from the surface side of the top sheet 30. In order to form the recesses E and F by such embossing, as the intermediate sheet 40, the basis weight is 8 to 60 g / m ² , the thickness is 0.2 to 1.5 mm, and the top sheet 30 is the basis weight. 15 to 80 g / m ² and a thickness of 0.2 to 3.5 mm are preferable because sufficient embossing can be performed under conditions that do not impair liquid permeability.

  Further, although not shown in the drawings, the embossed recess may be formed only in the intermediate sheet 40 without forming a recess in the top sheet 30, and the absorbent element may be formed without forming recesses in the top sheet 30 and the intermediate sheet 40. A concave portion by embossing may be formed only on 56, or a concave portion by embossing may be formed only on the absorbent body 58 without forming concave portions on the top sheet 30, the intermediate sheet 40, and the covering sheet 58.

  Further, although not shown, a concave portion by embossing can be formed in the thickness direction from the back surface side. Such a recess is formed by embossing so as to reach any member from the back side of the holding sheet 80, the covering sheet 58, the liquid-impermeable sheet 70 or the exterior sheet 12 to the top sheet 30. it can. 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. In this case, the product may be sandwiched between the engraving roll and the embossing may be performed simultaneously on the front and back.

  The embossed recesses E and F have the effect of inducing and diffusing the liquid in the extending direction. It also has the effect of increasing rigidity. Therefore, it is desirable to determine the shapes of the embossed recesses E and F 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.

  In particular, the embossed recess is preferably formed so as to reach the upper layer absorbent body 56A from the surface side of the top sheet 30 as shown in FIG. 3 or the like in the planar pattern shown in FIG. The embossed recesses F of the planar pattern have arc-shaped portions extending along the front-rear direction and having an intermediate part in the front-rear direction bulging toward the center in the width direction at least on both sides of the crotch portion. When such an arc-shaped portion is provided, the use surface at the center in the width direction can be raised from both sides, and the fit between the crotch and the crack can be improved. Moreover, in the embossing recessed part F of illustration form, between the front-and-back end parts of an inner arc-shaped part is connected by the part extended in the width direction, and the excretion site | part is surrounded by the cyclic | annular embossing recessed part F. A plurality of arc-shaped portions on both sides are formed at intervals in the width direction as shown in the figure. As a result, unnecessary diffusion of the liquid is suppressed by the embossed recess F, and the leakage preventing effect is excellent.

(Other)
Although not shown, the constituent members of the interior body 20 can be fixed to each other by solid, bead or spiral coating such as hot melt adhesive.

(Example of tape-type disposable diapers)
On the other hand, FIG.9 and FIG.10 has shown the example of the tape-type disposable diaper. FIG. 10 is a view taken along line 9-9 in FIG. 9, but the interior body 20 is slightly exaggerated.

  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 interior body 20 has an absorber 56 interposed between the top sheet 30 and the liquid-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 liquid-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 outside 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 liquid-impermeable sheet 70 by 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 end 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 end to the extending edge of the liquid-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 beginning of fixing of the inner surface of the barrier sheet 64 to the liquid-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.

<Example of how to make disposable diapers>
Next, an embodiment of the manufacturing method of the present invention will be described.

(Manufacturing process of absorbent element)
FIG. 11 shows an example of the manufacturing process of the absorbent element 50 shown in FIG. 3 and FIG. The covering sheet 58 is supplied to the line from the upstream side, and when the holding sheet 80 is provided next, the holding sheet 80 is supplied. In order to fix the lower layer absorbent body 56B supplied later, an adhesive such as a hot-melt adhesive having adhesiveness can be applied to the holding sheet 80 in advance.

  Subsequently, the lower layer absorbent body 56 </ b> B formed by mixing and stacking the pulp fibers 55 and the superabsorbent polymer particles 54 in the stacking drum device 91 is intermittently supplied onto the covering sheet 58 or the holding sheet 80. The Thereafter, the lower layer absorbent body 56 </ b> B is wrapped by the covering sheet 58 by passing through the sailor 92.

  On the other hand, after the intermediate sheet 40 is supplied and an adhesive such as a hot melt adhesive is applied to the upper surface of the intermediate sheet 40 from the nozzle 95, the toe 52Y is opened on the upper surface of the intermediate sheet 40 as the upper layer absorber 56A. The hard-absorbing filament aggregate 52Z formed by fiber is supplied and pasted. Details of the opening process will be described later. Instead of this step, the intermediate sheet 40 wider than the upper-layer absorbent body 56A is used, and after the hardly absorbent filament aggregate 52Z is disposed on the intermediate sheet 40, both sides of the intermediate sheet are difficult to cover using a sailor. The absorbent element shown in FIG. 4 can be manufactured by folding back and enclosing the absorbent filament aggregate 52Z.

  When the superabsorbent polymer particles are included in the upper layer absorbent body 56A, the superabsorbent polymer aggregate 52Z is superabsorbed by the SAP supply device 90 prior to attachment to the lower layer absorbent body 56B after the opening. Particles can be included. An example of the SAP supply device 90 will be described later.

  Subsequently, the hardly absorbable filament aggregate 52Z having the intermediate sheet 40 attached to the lower surface is cut into a predetermined length by a cutting and sticking device 93 such as a slip cutter, and the cut hardly absorbable filament aggregate is cut. Is affixed intermittently on the lower layer absorber 56B. That is, the cut hardly absorbable filament aggregates are sequentially attached to predetermined positions on the lower layer absorbent body 56 </ b> B conveyed with a predetermined interval.

  In the illustrated form, in front of the cutting and sticking device 93, the intermediate sheet 40 is on the bottom and the hardly absorbable filament aggregate 52Z is on the top. 40 is on the top and the hardly absorbent filament aggregate 52Z is on the bottom, resulting in the form shown in FIG. On the other hand, if it is configured not to be folded by the cutting and sticking device 93, the configuration shown in FIG.

  The lower layer absorbent body 56B to which the upper layer absorbent body 56A is affixed is then divided in the conveying direction by the cutter device 94 to form individual absorbent elements 50.

(In the case of pants-type disposable diapers)
Next, in the case of a pants-type disposable diaper, as shown in FIG. 12, the components of the barrier cuff 60 and the top sheet 30 are supplied from above, and the liquid-impermeable sheet 70 is supplied from below. Here, in the supply line of the barrier sheet 64 constituting the barrier cuff 60, the thread rubber 62 is stretched between the two nonwoven fabrics and the second liquid-impermeable sheet 72 is fixed in advance by a device (not shown). Supply is made in a state and is supplied to the main line together with the top sheet 30. The components of the barrier cuff 60, the top sheet 30 and the liquid-impermeable sheet 70 supplied to the main line are folded into a shape shown in FIG.

  And it cut | disconnects by the cutter apparatus 98 and the rectangular absorptive main body 20 whose longitudinal direction follows a conveyance direction is obtained. The obtained absorbent main body 20 is turned 90 degrees by the turning device 100 so that the longitudinal direction of the absorbent main body 20 is orthogonal to the line.

  On the other hand, in the line of the exterior sheet 12, the thread rubber 12C flows in advance (not shown) between the two nonwoven fabric sheets (not shown), and an elliptical shape is formed by a cutter (not shown) to form a leg periphery. When it is hollowed out and reaches the combination station 102, the absorbent main body 20 that has been turned around is placed on the combination station 102, fixed with a hot melt adhesive, etc., and bonded to the exterior sheet 12. Then, it is folded up and down with the horizontal line as a boundary, and the joining 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. Thereafter, the product is divided in the line direction (dividing means is not shown) to obtain individual products.

(In the case of tape-type disposable diapers)
On the other hand, FIG. 13 has shown the example of a manufacturing method of the tape-type disposable diaper shown in FIG.9 and FIG.10. The process until the individual absorbent element 50 is obtained is the same as that of the pants type. The top sheet 30 is supplied from above and the liquid-impermeable sheet 70 is supplied from below to the individual absorbent elements, and thereafter the barrier sheet 64 constituting the barrier cuff 60 is supplied. In the supply line of the barrier sheet 64, supply is performed in a state where the thread rubber 62 is fixed under stretch between two nonwoven fabrics in advance by a device (not shown). At the end of the line, the semi-finished product with the absorbent main body is divided by the cutter device 98 to obtain the product 10.

(Opening)
The opening process can be performed by a line having the form shown in FIG. 14, for example. That is, the toe 52Y is pulled out from the bail 52X, and is gradually widened through the widening device 120 and is guided to the thickening device 110 through the first nip 126A, the second nip 126B, and the third nip 126C. After the thickness is increased to a substantially final filament aggregate 52Z, the superabsorbent polymer particles 54 are sprayed and supplied by the superabsorbent polymer particle spraying means 90, and then to the sailor 92. It is sent. The tow is pulled out from the bale 52X by being pulled in by the first nip 126A (corresponding to a driving nip roll).

  Characteristically, the tow 52Y pulled out from the bail 52X is subjected to a first nip through a nip of a free nip roll 124 composed of a pair of nip rolls configured to rotate freely after the angle is changed by the turn portion 122. It is drawn in by 126A. In such a configuration, the transfer resistance of the free nip roll 124 (determined according to the nip pressure and the roll weight) functions as a brake that suppresses the pull-in speed of the tow 52Y, and the tension after the free nip roll 124 becomes stable. This is because the rotation of the free nip roll 124 occurs only when the tow passes.

  The nip pressure and the own weight of the free nip roll 124 may be determined as appropriate. In normal cases, the nip pressure is preferably more than 0 MPa and less than 5 MPa, and the roll weight is more than 0 kg and less than 10 kg per roll. Is preferred. Within this range, stabilization of the tension can be easily realized.

  Thus, the supply amount of the tow 52Y to the first nip 126A that controls the supply amount of the tow becomes stable, so that the size, weight, and quality of the absorbent body become stable.

  The tow 52Y pulled out from the bale 52X is between the bale 52X and the free nip roll 124, between the free nip roll 124 and the first nip 126A, between the first nip 126A and the second nip 126B, and second. The widening device 120 provided between the nip 126B and the third nip 126C respectively widens in steps to a desired width. At this time, it can also be enlarged in the thickness direction.

  15 and 16 show an example 120 of a widening device. The widening device 120 has a rectangular tube passage 120A having a predetermined width X through which the tow passes, and a compressed air jet outlet 120B formed on a surface along the width direction on the inner surface of the passage 120A, and is introduced into the passage 120A. The tow 52Y is widened to the full width of the passage by the force of compressed air. The height of the passage is equal to or greater than the thickness of the tow 52Y to be introduced. When the thickness of the passage is higher than the thickness of the tow 52Y, the tow 52Y is also expanded in the thickness direction.

  As shown in FIG. 16, the spout 120B is line-symmetric with respect to the center in the width direction of the passage 120A, and has a dogleg shape (or V-shape) located downstream in the toe passage direction toward the center in the width direction of the passage 120A. Shape) is a slit.

  When the tow enters the passage 120A in a state where air is ejected from the slit 120B, the tow 52Y has a width so as to receive the force of the compressed air in a balanced manner even if the entry position is deviated from the center in the width direction. The tow 52Y is naturally guided to the center in the width direction of the passage 120A. That is, the introduction position of the toe 52Y can be centered using compressed air for widening. Further, in this embodiment, since the tow 52Y is guided in a non-contact manner, there is an advantage that damage and collapse of the tow are less likely to occur compared to the case where the tow 52Y is guided by contact. Further, the widening device 120 having such a centering function exhibits not only the centering in the widening but also the function of correcting the transfer position.

  When performing the centering using the compressed air as described above, the shape of the slit is not limited to the square shape, the line is symmetrical with respect to the center in the width direction of the passage 120A, and the toe passing direction is directed toward the center in the width direction of the passage 120A. As long as the conditions located on the downstream side are satisfied, it may be formed in a curved shape, an arc shape, or the like.

  On the other hand, tension is applied between the first nip 126A and the second nip 126B so as to apply tension to the tow 52Y, and conversely, the second nip 126B and the third nip 126C are relaxed. In addition, the peripheral speed of each nip roll is set. As a result, tension is applied to the tow 52Y between the first nip 126A and the second nip 126B, so that the entanglement between the filaments is forcibly removed to some extent, and the separation of the filaments is promoted. With the separation, the toe 52Y is widened by the widening device 120, so that the tow 52Y can be further uniformly widened. Further, the tow 52Y is widened by the widening device 120 while the tow 52Y is relaxed between the second nip 126B and the third nip 126C, so that the toe 52Y can be further uniformly widened.

  In a more preferred form, one roller of the second nip 126B is formed with a large number of continuous grooves in the circumferential direction at small intervals in the longitudinal direction. This groove has a function of accelerating tow breaking by allowing the filament to enter into a large number of grooves. Further, in this case, in order to enhance the effect of the groove, the holding angle of the toe 52Y (the rotation direction angle of the toe contact portion) in one grooved roller of the second nip 126B is increased, and the tow 52Y and the grooved roller are Increasing the contact area is also a preferred form. Specifically, the angle formed by the tow 52Y upstream of the second nip 126B and the tow 52Y downstream, that is, the direction change angle by the grooved roller is less than 180 degrees, particularly an acute angle (smaller than 90 degrees). It is preferable to configure.

  In addition, the first nip 126A, the second nip 126B, and the third nip 126C may have different combinations of roll diameters, but in that case, the tension applied to the tow 52Y between the rolls due to the difference in peripheral speed, Since the contact resistance between the roll and the tow 52Y and the like may be non-uniform in the toe width direction, it is preferable that all of them be configured in common.

  Next, the tow that has passed through the third nip 126 </ b> C is guided to the thickening device 110. The thickening device 110 has a structure similar to that disclosed in, for example, Japanese Patent Application Laid-Open No. 59-500392 (WO 83/03267), and schematically shows an inlet 110A and an outlet 110B as shown in FIG. A venturi section 110b is formed between the venturi section 110b, a compressed air inlet 110a on the inlet side, and an air exhaust hole 110c in the venturi section 110b. In plan view, it is substantially rectangular, and is flat in a direction penetrating the paper surface of FIG.

  When the compressed air is blown from the blowing port 110a, air enters from the inlet 110A by the ejector effect, and as a result, the tow 52Y is drawn and a forward force is applied. When the toe 52Y reaches the venturi section 110b, the air is exhausted from the air exhaust hole 110c, and the space of the venturi section 110b is enlarged, so that the bulk of the tow 52Y mainly increases in the thickness direction, and the thickness increases. Enlarged. In addition, by making the width | variety of a channel | path wider than the width | variety of the toe 52Y introduce | transduced, widening is also possible as shown in the downward direction of FIG. Thus, the tow can be opened.

(SAP supply equipment)
As the SAP supply device 90, a device that disperses the superabsorbent polymer particles substantially in the entire thickness direction with respect to the filament aggregate 52Z unit is preferable. As such a superabsorbent polymer particle spraying means 90, a means for giving an acceleration force as well as a dropping force due to the weight of the superabsorbent polymer particle itself is desirable. An example of this is shown in FIG. That is, a rotary drum 90b having a projection hole 90d in a casing 90a having an opening in the lower part is configured to rotate in the moving direction of the web (counterclockwise in FIG. 18), and a shutter drum 90c is provided therein. It is a thing. The projection unit 90A having these as elements is connected to a hopper that stores superabsorbent polymer particles, and the superabsorbent polymer particles 54 from the hopper are configured to be supplied into the rotary drum 90b.

  In this SAP supply device, the opening position of the shutter drum 90c is adjusted in advance with respect to the opening position of the casing 90a. The state of FIG. 18 shows a fully open state that is completely coincident. Further, the projection holes 90d of the rotary drum 90b are divided into four groups in the circumferential direction as shown in the drawing as a group divided in the circumferential direction. Therefore, in the process shown in the drawing, four sheets of paper diapers are rotated. In contrast, superabsorbent polymer particles are dispersed and projected.

  The superabsorbent polymer particles 54 may be continuously dispersed and projected onto the aggregate of the filaments 52. However, when the absorbent elements 50 are divided in the line direction by the cutter device 94 to form individual absorbent elements 50, Due to the presence of the superabsorbent polymer particles 54, the blade of the cutter device 94 is worn out in a short time. Therefore, it is desirable that the superabsorbent polymer particles 54 are not continuously scattered and projected, but intermittently sprayed and projected only on the zone Z as shown in FIG.

  For this reason, as described above, the projection holes 90d of the rotary drum 90b are formed as a group divided in the circumferential direction, in the figure, divided into four groups in the circumferential direction, thereby forming the superabsorbent polymer particles 54. Is intermittently scattered and projected only in the zone Z. As a result, the zone Z can be divided between the zones Z by the cutter device 94, and wear of the blade of the cutter device 94 can be suppressed.

  The amount of the superabsorbent polymer particles sprayed can be adjusted mainly by adjusting the opening diameter of the projection hole 90d and the position of the opening of the shutter drum 90c with respect to the opening position of the casing 90a. The position should be followed. Moreover, the dispersion pattern of the superabsorbent polymer particles can be adjusted by the arrangement of the divided projection holes 90d.

  On the other hand, if necessary, the superabsorbent polymer particles 54 are dispersed and projected onto the aggregate of the filaments 52 together with the pressure air, so that the superabsorbent polymer particles are substantially entirely in the thickness direction with respect to the aggregate of filaments. It is also possible to disperse them. However, the superabsorbent polymer particles dispersed and projected on the aggregate of filaments 52 may be scattered by the pressure air and scattered outside the predetermined region.

  Further, together with or instead of the SAP supply device 90, the superabsorbent polymer particles 54 dispersed on the filament aggregate may be sucked from below the filament aggregate.

  Moreover, it can replace with the SAP supply apparatus 90 which applies the above-mentioned centrifugal component force, and can also use the general purpose SAP supply apparatus of the type which makes a superabsorbent polymer particle fall only by dead weight.

  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. 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 sectional drawing of another example. It is an expanded state top view of a tape type disposable diaper. FIG. 10 is a cross-sectional view taken along line 9-9 in FIG. 9. It is a schematic diagram which shows the example of manufacturing equipment of an absorption element. It is a schematic diagram which shows the example of manufacturing facilities of a pants-type paper diaper. It is a schematic diagram which shows the example of manufacturing equipment of a tape-type disposable paper diaper. It is a schematic diagram of the opening facility. It is a schematic diagram of a widening apparatus. It is XV-XV sectional drawing of FIG. It is a schematic diagram of a thickening apparatus. It is a schematic diagram of an example of a SAP supply device.

  DESCRIPTION OF SYMBOLS 10 ... Pants type disposable diaper, 10A ... Tape type disposable diaper, 12 ... Exterior sheet, 12A ... Back sheet, 20 ... Interior body, 30 ... Top sheet, 40 ... Intermediate sheet, 50 ... Absorption element, 52 ... Difficult absorption filament, 52X ... Veil, 52Y ... Tow, 52Z ... Aggregation of filaments, 54 ... Superabsorbent polymer particles, 56 ... Absorber, 56A ... Upper layer absorber, 56B ... Lower layer absorber, 58 ... Cover sheet, 60, 60A ... Barrier cuffs, 64: barrier sheet, 70: liquid impermeable sheet, 72: second liquid impermeable sheet, 80: holding sheet, E: heat fusion part.

Claims (2)

It has an absorption element that absorbs liquid that has passed through the top sheet on the use surface side,
The absorbent element has a lower layer absorber and an upper layer absorber provided on the top sheet side,
The lower layer absorbent is composed of an aggregate of pulp fibers or filaments and superabsorbent polymer particles, and is wrapped in a covering sheet,
The upper-layer absorber is obtained by opening a tow, and sticking a hardly absorbable filament aggregate having an absorption amount of 1.0 times or less of its own weight to a liquid-permeable sheet different from the covering sheet, or The filament aggregate is wrapped with a liquid permeable sheet different from the enveloping sheet, and the filament extends along the top sheet, and both ends of the filament are inside from the periphery of the lower layer absorbent body. 10 to 300 mm apart,
A method for producing an absorbent article characterized by comprising:
In manufacturing the absorbent element,
While producing the lower layer absorbent body by wrapping an aggregate of pulp fibers or filaments and superabsorbent polymer particles in a covering sheet,
A difficult-to-absorb filament assembly obtained by opening a tow and having an absorption amount of 1.0 times or less of its own weight is attached to a liquid-permeable sheet different from the envelope sheet, or the envelope sheet After wrapping with another liquid-permeable sheet, the upper absorbent body is manufactured by cutting at a predetermined interval in the continuous direction of the hardly absorbent filament,
The upper layer absorbent body, as both ends of the filament 10~300mm spaced inwardly from the periphery of the lower absorbent body, predetermined upper pulp fibers or filaments aggregate of the top of the lower absorbent body or the lower absorbent body The manufacturing method of the absorbent article characterized by sticking to a position. A step of affixing the liquid permeable sheet to the hardly absorbent filament aggregate, a step of intermittently spraying and projecting highly absorbent polymer particles on the hardly absorbent filament aggregate, and a step of cutting an intermittent portion of the absorbent polymer particles, a manufacturing method of an absorbent article according to claim 1.

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