JP2006014886A - Absorbent body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent body having no settling and superior liquid permeability. <P>SOLUTION: This absorbent body is provided with a rattan area composed of a fiber assembly composed of rattan, and a thickness retention area composed of an absorbent material other than the rattan and having a compression workload in or after pressurization smaller than that of the rattan area. The absorbent body, in the thickness retention area, is formed of a material containing at least one of pulp fibers, a porous foam material, cotton fibers and nonwoven fabric. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an absorbent body for use in absorbent articles such as disposable diapers and sanitary napkins intended to absorb body fluids such as sweat, urine and menstrual blood.

  Absorbent articles such as sanitary napkins and disposable paper diapers usually have a structure in which an absorbent for absorbing and holding body fluid is interposed between a liquid-impermeable back sheet and a liquid-permeable top sheet. In such an absorbent article, the consumer always demands a product that is thin, light, less uncomfortable when worn, and excellent in liquid permeability.

  Since the weight, thinness, and liquid permeability of absorbent articles largely depend on the absorbent body, it is regarded as an industry effort to reduce the weight and thickness of the absorbent body and improve the high liquid permeability. ing. As shown in the following prior art documents, various techniques for improving the function of the absorber are disclosed.

  For example, JP-A-8-24289 discloses a surface material made of cotton and an absorbent material made of a hydrophilic nonwoven fabric. This absorbent material mainly comprises hollow synthetic fibers composed of fibers having an average fiber diameter of about 1 to 3 denier and having an average fiber diameter of about 4 to 8 denier in order to provide an overall elastic return to deformation. Yes. This bodily fluid absorbing material is intended to prevent the occurrence of twist caused by using a surface material made of cotton by using an absorbent material containing the hollow synthetic fiber.

Japanese Patent Application Laid-Open No. 63-109859 discloses an absorbent article having an absorbent containing hydrophilic fibers and a superabsorbent polymer, in which the absorbent is provided with an acquisition band and a storage band located around the acquisition band. And the acquisition zone has a lower density and lower basis weight than the storage zone. In this absorbent article, the liquid is transferred from the acquisition zone to the storage zone so that the superabsorbent polymer contained in the storage zone does not cause gel blocking.
JP-A-8-24289 JP 63-109859 A

  However, the absorbent body constituting the absorbent article described in the above document has the following drawbacks and there is room for improvement. The absorbent body disclosed in JP-A-8-24289 has low liquid permeability because the surface material is made of cotton, and the absorbed menstrual blood tends to stay on the surface material, giving a very dirty impression to the user. There is a drawback.

  On the other hand, the absorber disclosed in JP-A-63-109859 is composed of conventionally known hydrophilic fibers and superabsorbent polymers in both the acquisition zone and the storage body, although there are differences in density and basis weight. The liquid permeability of the acquisition zone and the storage body itself is not different from other conventional products using this type of absorbent material.

  Therefore, the main problem of the present invention is to improve the drawbacks and improvement points included in the prior art also shown in the above example, there is no sag, liquid permeability is improved, and softness is also improved. It is to provide an absorber.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
An absorbent body comprising: a tow region composed of a fiber assembly made of tow; and a thickness maintaining region made of an absorbent material other than tow and having a smaller compression work (WC) than the tow region.

<Invention of Claim 2>
The absorber according to claim 1, wherein the thickness maintaining region is made of a material containing at least one of pulp fiber, porous foam material, cotton fiber, and nonwoven fabric.

<Invention of Claim 3>
The absorber according to claim 1 or 2, wherein the toe region and the thickness maintaining region have a laminated structure.

<Invention of Claim 4>
The absorber according to claims 1 to 3, wherein the toe region extends along the longitudinal direction at a central portion in the width direction within a range not reaching the peripheral portion.

<Invention of Claim 5>
The absorber according to any one of claims 1 to 4, wherein the tow region is exposed on at least the front and back surfaces.

<Invention of Claim 6>
The absorber according to any one of claims 1 to 5, wherein the tow region is exposed on at least the front and back surfaces of the absorber, and the exposed portion is formed to be bulkier than other portions.

<Invention of Claim 7>
The absorber according to any one of claims 1 to 6, wherein the thickness maintaining region includes a recess, and the toe region is located in the recess.

<Invention of Claim 8>
The absorber according to claim 1, wherein the thickness maintaining region has a laminated structure.

<Invention of Claim 9>
The absorber according to claim 1, wherein the density of the tow region is in the range of 10 to 100 g / m ³ and the density of the thickness maintaining region is in the range of 10 to 100 g / m ³ .

<Invention of Claim 10>
The absorbent according to any one of claims 1 to 9, wherein the tow is cellulose acetate tow.

<Invention of Claim 11>
The absorbent article according to any one of Claims 1 to 10, wherein the fiber assembly is a structure in which fibers are joined together by dots, lines or spots.

  Since the tow has a structure in which the fiber arrangement is directional and the gap between the fibers is large with respect to the amount of fibers, when bodily fluid is dropped onto the tow region composed of a fiber assembly made of tow, the bodily fluid Moves into the gap while moving very fast along the fiber flow direction, and therefore has a liquid permeability that is remarkably excellent even when formed thinner than conventional absorbent materials. It is also very light and soft.

  However, since the tow has a large amount of compression work, if the absorbent body is composed only of the tow, it is easy to sag due to pressurization (for example, body pressure when used as an absorbent article). When this occurs, the fibers are in close contact with each other and voids are reduced, making it difficult to recover. If it does so, the high liquid permeability which a tow has will be reduced.

  In the absorbent body of the present invention, the thickness maintaining region supplements the thickness reduction in the toe region and the resulting decrease in stiffness during liquid permeation, and the thickness of the entire absorbent body during pressurization, after pressurization or after liquid permeation There is little decline and the suppression of sag is achieved. Therefore, it is excellent in liquid permeability and soft. In addition, since the tow region does not sag, excellent liquid permeability unique to the tow is maintained.

  In particular, when the tow region and the thickness maintaining region have a laminated structure, the toe region is supported by the thickness maintaining region and has a high liquid permeability that the tow region has, and becomes a less stubborn absorber.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.
<Absorber structure>
The absorbent body of the present invention is suitable as a constituent article of an absorbent article, is a flat article having an appropriate thickness, and can have an appropriate shape such as a bowl shape, a gourd shape, or an elliptical shape in plan view.

1 to 10 and 26 are plan views of the absorbent body example X of the present invention, and FIGS. 11 to 25 and 27 are cross-sectional views in the width direction of the absorbent body example of the present invention. The absorbent body X of the present invention comprises a tow region A composed of a fiber assembly made of tow, and a thickness maintaining that is made of an absorbent material other than tow and has a reduced thickness reduction during and after pressurization than the tow region. Regions B and B ′. The toe region A is composed of a fiber assembly made of tows described later. Since the fiber group constituting the toe region A is arranged with directionality and has a large number of voids between the fibers, the body fluid permeability is remarkably superior and the body fluid permeation rate is faster than that of the conventional absorbent material. It is also light and thin. On the other hand, the thickness maintaining regions B and B ′ are made of an absorptive material other than tow, for example, a conventionally known absorptive material such as pulp fiber. The thickness maintaining regions B and B ′ are intended to complement thickness reduction during pressurization such as body pressure of the toe region A and to suppress sag caused by the thickness reduction. There is a need to configure less degradation. Whether the thickness reduction is large or small can be expressed by the compression work (WC). When the compression work (WC) is low, the thickness decrease after pressurization or after pressurization is less likely to decrease, but when the compression work (WC) is high, the thickness decrease after pressurization or after pressurization tends to be large. . The compression work (WC) can be measured by, for example, a handy compression tester (KES-G5: manufactured by Kato Tech). More specifically, in the above-described testing machine, the size and shape of the test piece: 200 mm length × 50 mm width saddle shape, measurement location: 200 mm length × 50 mm width central portion, measurement conditions; SENS: 2, type of force gauge 1 kg, SPEED RANGE: 0.1, DEF sensitivity: 20, pressurization area 2 cm ² , uptake interval: 0.1 (standard), STROKET SET: 5.0, upper limit load 50 gf / cm ² . And when using as an absorber of an absorbent article, it is desirable that the compression work (WC) of the thickness maintaining regions B and B ′ is 1.0 to 3.0 gfcm / cm ² , and the toe region A is It is desirable that it is 3.0-10.0 gfcm / cm < ² >. In addition, in order to make the work of compression (WC) between the toe region A and the thickness maintaining regions B and B ′ different within a preferable value range, the thickness maintaining regions B and B ′ are made of a material other than the tow, This can be easily achieved when the density of the tow region is in the range of 10 to 100 kg / m ³ and the density of the thickness maintaining regions B and B ′ is in the range of 10 to 100 kg / m ³ .

  Next, the arrangement of the tow region A and the thickness maintaining regions B and B ′ in the absorber in the plan view will be described with reference to the plan view. As shown in FIGS. 1 to 10, the tow region A is preferably exposed on at least one of the front and back surfaces of the absorbent body X. In this case, for example, when used as an absorbent body such as a sanitary napkin, the absorbent article is configured such that the exposed surface of the tow region is disposed on the use surface (the surface close to the body fluid discharge position). When the body fluid such as menstrual blood is discharged, it is quickly absorbed into the toe region A and reaches the thickness maintaining region B to be held and stored. In addition, since the liquid permeability of the toe region A is high, menstrual blood does not stagnate on the surface, and menstrual blood remains on the surface material and gives the user an impression that it is soiled. Furthermore, since the liquid permeability of the site | part close | similar to the use surface side does not fall, it becomes a thing which is hard to leak.

  The amount of exposure and the exposure position with respect to the surface of the absorbent body can be appropriately changed depending on the use mode, for example, the position when incorporated in the absorbent article. In addition, it is desirable not to arrange the toe region A in the peripheral portion of the absorber. When the toe region A is located at the peripheral edge, the thickness tends to decrease at the peripheral edge of the absorber, so that the body fluid discharged to the central portion of the absorber easily flows toward the peripheral edge, and the body fluid is absorbed. The risk of spilling out of the body increases. If used for sanitary napkins and disposable diapers, the tow region A is arranged so as to extend in the longitudinal direction in the central width direction of the absorbent body as shown in FIG. As shown in FIG. 4, it is preferable to place them in a spot-like manner relative to the body fluid discharge site, or to have a shape in which the front side is wide and the rear side is narrowed as shown in FIG. By incorporating the absorbent body so that the longitudinal direction of the absorbent body is the longitudinal direction of the sanitary napkin, the toe region A can be easily positioned only in the vicinity of the body fluid discharge site such as the menstrual discharge position, It can also be manufactured at low cost as an inexpensive material.

  Further, the absorbent body X of the present invention may be embossed. The embossing mode is not particularly limited, but when embossing is applied to the tow region A, the liquid permeability of the tow region A is reduced by pressing, which is not desirable. As an example of the absorbent body X to which the emboss e is applied, as shown in FIG. 5, in the front and rear of the toe region A arranged in a spot manner, the thickness maintaining region B is linear in the width direction. As shown in FIG. 6 in which the embossed e is provided, a plurality of linear embossed e are provided in the longitudinal direction of the thickness maintaining region B at the front and rear of the toe region A arranged in a spot manner. As shown in FIG. 7, on both sides of the toe region A arranged so as to extend in the longitudinal direction in the central width direction of the absorbent body X, a line along the longitudinal direction with respect to the thickness maintaining region B is provided. As shown in FIG. 8, the embossed e is provided in the shape, on both sides of the tow region A arranged so as to extend in the longitudinal direction in the central width direction of the absorbent body X, with respect to the thickness maintaining region B , Longitudinal center from front of absorber X Form embossing e is attached to the linear toward the along and obliquely rearward from the center portion to the toe region A to, is preferred. The tow region A can be easily positioned at a body fluid discharge site such as a menstrual discharge position by incorporating the absorbent body X having such an embossed e form so that the longitudinal direction thereof coincides with the longitudinal direction of a sanitary napkin or the like. In addition, the bodily fluid discharged toward the toe region A diffuses along the emboss e, and the absorbent article is difficult to leak sideways. Furthermore, when incorporating the absorbent body into the absorbent article, a liquid permeable sheet material, a so-called second sheet, may be provided between the absorbent body and the liquid permeable top sheet. In this case, the second sheet and the present invention are provided. It is possible to take a form in which embossing is provided integrally with the absorbent body. For example, as shown in FIGS. 9 and 10, the use surface side of the tow region A arranged in a spot manner is covered with the second sheet S, and the toe region A is surrounded by the second sheet S and the thickness maintaining region B. Thus, a form in which the emboss e is provided in a linear shape is preferable. In such a form, the integrity of the second sheet S and the absorbent body X is enhanced, and the absorbent article can be suitably exerted by the function of preventing side leakage by embossing and the function of returning the body fluid by the second sheet.

  Next, the arrangement of the tow region A and the thickness maintaining regions B and B ′ in the absorbent body in a sectional view will be described with reference to cross-sectional views. As shown in FIGS. 11 to 25, as an example of the cross-sectional structure of the absorber, the thickness maintaining region B is a mode in which the tow region A is exposed on at least the surface of the absorber (the use surface when incorporated in the absorbent article). , B ′ and the toe region A are preferably laminated. In this case, if the tow region exposed surface is incorporated in the absorbent article so that the use surface of the absorbent article is located on the side of the absorbent article, it is assumed that the use surface is added and the body pressure causes a slight sag in the toe region. However, since the thickness and the appropriate rigidity of the entire absorbent body are maintained by the thickness maintaining regions B and B ′ where the non-use surface is located on the side, the thickness of the absorbent body as a whole is not reduced and there is no feeling of sagging. It will be a thing.

  In the case of such a laminated structure, as shown in FIGS. 11 to 22, a form in which the toe region is positioned in the concave portion formed on the use surface side of the thickness maintaining region B is preferable. In such a structure, the body fluid taken into the tow region A is easily diffused and absorbed in the thickness maintaining region B, and the body fluid that is not fully diffused in the toe region A is retained and becomes a more permeable absorber, Absorber that does not leak sideways. Moreover, since the thickness maintenance area | region B is made into the thickness at least in the width direction both sides of an absorber, there exists an effect which supports a body in the thickness part which concerns, and the toe | toe area | region A arrange | positioned at a recessed part does not sag easily. is there.

  As a specific example of disposing the toe region in this recess, as shown in FIG. 11, the toe region A is formed in the recess of the thickness maintaining region B in which the use surface is formed by pressing, excavating or the like on the center portion of the hook. 12, the form in which the toe region A in FIG. 11 is formed in a bulky manner, as shown in FIG. 13, the use surface is pressed against the center of the wrinkle by excavation, etc. In the concave portion of the thickness maintaining region B in which the concave portion is formed, a toe region formed by folding both side portions in the width direction of the sheet-like fiber assembly to the back side (non-use surface) and increasing the thickness is disposed. Forms.

  In addition, as shown in FIG. 14, the use surface is folded back into the width direction both sides of the thickness maintaining region material such as sheet-shaped crimped pulp, and the use surface is formed with a recess in the width direction center portion, The form in which the concave tow area is arranged, as shown in FIG. 15, the form in which the tow area A in FIG. 14 is formed in bulk, the thickness of sheet-like crimped pulp, etc., as shown in FIG. The use surface is folded back on both sides in the width direction of the maintenance region material, the use surface is formed with a recess at the center in the width direction, and the toe region extends over the entire use surface side of the recess and the thickness maintenance region B. As shown in FIG. 17, the use surface is folded in the width direction on both sides of the thickness maintaining region material such as the sheet-like crimped pulp, and the use surface is the center in the width direction of the wrinkle. A concave portion is formed in the portion, and the outer surface of the concave portion and the thickness maintaining region B Form surrounding the body toe region is located may also be mentioned.

  Further, as shown in FIG. 18, a toe region A is disposed inside a thickness maintaining region B having a substantially C-shaped cross section that opens on the use surface side, and the back surface of the toe region A (non-use surface is in the thickness maintaining region B). )) And a form in which both sides are surrounded, as shown in FIG. 19, in the form shown in FIG. 18, the tow region A included in the thickness maintaining region is used on both sides of the sheet-like fiber assembly. 20, the tow region A included in the thickness maintaining region in the form shown in FIG. 18 folds both sides of the sheet-like fiber assembly to the use surface side as shown in FIG. The form which is formed in piles and the other absorptive material is arrange | positioned at the folding part is mentioned. In the absorbent body of the form shown in FIGS. 18 to 20, the body fluid that has penetrated into the tow region A leaks from both sides in the width direction of the toe region because both sides of the toe region in the width direction are surrounded by the thickness maintaining region. Therefore, an absorbent article incorporating this form of absorbent body is an absorbent article that is extremely difficult to leak sideways.

  In the above example, the thickness maintaining region B is one region, but it may be composed of a plurality of regions. For example, as shown in FIGS. 21 to 23, the thickness maintaining regions B and B ′ may have a laminated structure. If it is set as the structure shown in FIGS. 21-23, the liquid absorption amount in thickness maintenance area | region B, B 'can be increased, and when it is set as laminated structure, thickness maintenance of each thickness maintenance area | region B, B' is carried out. By appropriately designing the rate, the specification according to the use mode can be obtained. For example, when used for sanitary napkins and paper diapers, it is possible to improve the fit.

  In addition, it can also be set as the form which does not have a recessed part in a thickness maintenance area | region. If a specific example is shown, as shown in FIG. 24, the tow | toe area | region A is provided so that the front and back may be penetrated, and the tow | toe area | region comprised with a sheet-like fiber assembly as shown in FIG. A form in which both side portions of A are sandwiched between thickness maintaining regions B and B formed by substantially forming a sheet-like thickness maintaining region constituent material as a C-fold is mentioned. In these forms, the toe region A and the thickness maintaining region B do not have a laminated structure in the central portion in the width direction of the absorber, but there is no decrease in thickness of the thickness maintaining region B disposed on both sides of the absorber X. The toe area A does not fall. Moreover, since the thickness as the whole absorber is ensured, a user does not feel thinness.

  Note that the tow region A is not limited to one place, and may be configured to exist at a plurality of places as shown in the plan view shown in FIG. 26 and the cross-sectional view shown in FIG. The design can be changed as appropriate within the scope of the present invention.

  Moreover, the absorber of this invention can also be made into the form on which several tow | toe area | regions A and A were laminated | stacked. Specifically, as shown in FIG. 28, the toe area A on the use surface side is formed wider than the toe area A ′ on the back side, and as shown in FIG. 29, the toe area on the use surface side. The form in which the width of the area A and the toe area A ′ on the back surface side is the same, as shown in FIG. 28, the form in which the toe area A on the use surface side is formed narrower than the toe area A ′ on the back surface side. It is done. When the plurality of tow regions A and A ′ are provided, the density, bulk, width, denier of the constituent fibers, etc. may be appropriately changed in addition to the width of each tow region. Furthermore, as shown in FIG. 31, a plurality of tow regions A, A ′, A ″ separated in the width direction of the absorber may be arranged. Also in this case, the density, bulk, width, denier of the constituent fibers, and the like of each toe region A, A ′, A ″ can be appropriately designed.

<Composition of fiber assembly>
The fiber assembly used in the present invention is composed of tows (fiber bundles) composed of fibers. Examples of tow fibers include polysaccharides or derivatives thereof (cellulose, cellulose ester, chitin, chitosan, etc.), synthetic polymers (polyethylene, polypropylene, polyamide, polyester, polylactamamide, polyvinyl acetate, etc.), and the like. In particular, cellulose esters and cellulose are 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 a spun fiber. The shape and size of cellulose is a continuous fiber that can be regarded as a substantially infinite length and has a long diameter of several millimeters to several centimeters (for example, 1 mm to 5 cm), and a particle diameter of about several microns (for example, 1 to 100 μm). Can be selected from various sizes up to a fine powder. Cellulose may be fibrillated, such as beaten pulp.

  Examples of cellulose esters 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 polycaprolactone Cellulose ester derivatives such as 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. 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.

  The tow of the present invention may contain other fibers such as rayon fiber, polypropylene fiber, polyethylene fiber, polyester fiber and nylon fiber as long as it contains cellulose ester fiber.

  The tow constituent fiber 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 tow constituent fibers can be, for example, about 1 to 16 denier, preferably about 1 to 10 denier, and more preferably about 2 to 8 denier. The tow constituent fiber 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 tow constituting fiber is not particularly limited, and may be any one of, for example, a circular shape, an oval shape, an irregular shape (for example, a Y shape, an X shape, an I shape, an R shape) or a hollow shape. Also good. The tow constituent fibers can be used, for example, in the form of tows (fiber bundles) 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 bundling about 3,000 to 1,000,000 continuous fibers.

  Since the tow is weak in entanglement between fibers, a binder can be used mainly for the purpose of maintaining the shape by connecting the fibers with dots, lines or spots. The binder includes triacetin, triethylene glycol diacetate, triethylene glycol dipropionate, dibutyl phthalate, dimethoxyethyl phthalate, citric acid triethyl ester, and other plastic resins, as well as various resin adhesives, especially thermoplastic resins. Can be used.

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

  Examples of water-insoluble or hardly water-soluble resins include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer and other olefinic homo- or 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, polyesters that may be modified, nylon 11, nylon 12, nylon 610, nylon 612 and other polyamides, rosin derivatives (for example, 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.

  Moreover, the superabsorbent polymer may be interspersed inside or at least one of the surface of the fiber assembly. As the superabsorbent polymer, a polymer that absorbs and retains bodily fluids, for example, ten times or more of its own weight can be used. Examples include starch-based, cellulose-based and synthetic polymer-based starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, cross-linked sodium carboxymethyl cellulose and acrylic acid. A (salt) polymer or the like can be used. As the shape of the superabsorbent polymer, a commonly used granular material is suitable.

The superabsorbent polymer can be appropriately determined according to the amount of absorption required for the use of the absorber. Therefore, although it cannot be said unconditionally, for example, in the case of sanitary napkins, paper diapers, etc., it can be sprayed so as to be ³ to 400 g / m ² .

  The quantitative arrangement of the superabsorbent polymer with respect to the fiber assembly, the density distribution, and the fiber density are preferably uniform for the purpose of general purpose, but when aiming to exhibit special absorption characteristics, It is also preferable to bias according to the purpose.

  Moreover, since a fiber assembly becomes easy to flow a liquid along the continuous direction of a fiber, it can provide a special absorption characteristic by biasing the density of a fiber. Such a means for biasing the fiber density can be achieved by performing uneven fiber opening at the time of manufacturing the fiber assembly or by using a plurality of tows in a bundle. As a specific method of biasing, for example, the fiber density of the intermediate portion in the width direction of the fiber assembly can be biased so as to be higher than both side portions. In this case, more liquid flows along the continuous direction of the fibers in the intermediate portion in the width direction of the fiber assembly.

<Method for producing fiber assembly>
A fiber assembly made of tows constituting the tow region A can be produced by a known method, and if necessary, it can be opened in a strip shape so as to have a desired size and bulk. The opening width of the tow is arbitrary, and can be, for example, about 100 to 2000 mm, preferably about 150 to 1500 mm. Opening the tow is preferable because the movement of the superabsorbent polymer described later becomes easier. Moreover, the rigidity of an absorber can be adjusted by adjusting the degree of tow opening.

  As a method for opening a tow, for example, a method in which a tow is passed over a plurality of opening rolls and the width of the tow is gradually expanded as the tow progresses, and tension (elongation) and relaxation of the tow ( (Shrinkage) can be repeated, and a method of widening and opening using compressed air can be used.

  In addition, as a method of dispersing the superabsorbent polymer in the fiber assembly, after spreading the superabsorbent polymer on the widened and opened fiber assembly, the surface opposite to the sprayed surface is sucked drum, etc. And a method of moving the dispersed polymer to the inside by suctioning with an appropriate suction force.

  In particular, in manufacturing a fiber assembly used for an absorbent body in which a plurality of tow regions A and A ′ as shown in FIGS. 28 to 31 are laminated, as shown in FIG. The tow A1 and the tow A2 that have been opened are made into a laminated state by two pairs of rolls R1, R1, R2, and R2, and then cut to an appropriate size. Further, in manufacturing a fiber assembly used in an absorbent body in which a plurality of tow regions as shown in FIG. 31 are provided in the width direction, as shown in FIG. 33, tows A4 constituting the toe region A, The tows A3 constituting the toe area A ′ and the tows A5 constituting the toe area A may be gathered by various rollers R3 to R5, and then cut to an appropriate size.

<About thickness maintenance area>
A conventionally known absorbent material can be used as the material constituting the thickness maintaining regions B and B ′, and the manufacturing method can also be manufactured by a conventionally known manufacturing method. However, since the thickness maintaining regions B and B ′ are intended to improve the decrease in the thickness maintaining rate of the entire absorber due to the arrangement of the toe region, the thickness maintaining rate is low in relation to the toe region. It is not desirable to be made of such a material.

  As specific materials suitable for the thickness maintaining regions B and B ′, pulverized pulp made from pulp fibers, crimped pulp, cotton fibers, nonwoven fabrics made of chemical fibers, porous foam materials, and the like are suitable. . Of course, the superabsorbent polymer of the same kind as the above-described fiber assembly may be interspersed as appropriate in the thickness maintaining regions B and B ′.

  On the other hand, in the thickness maintenance area | region B, when providing a recessed part, a recessed part can be provided by the embossing by a convex roll, or excavation with a drilling apparatus. It can also be formed by folding back both sides of the sheet-like thickness maintaining region constituent material. Preferably, it is desirable to give a larger core embossing and to give a fine embossing finer than the core embossing to the core embossing giving surface. When the fine embossing is formed, the contact surface between the thickness maintaining region B and the toe region is widened, so that the body fluid is quickly transferred from the toe region to the thickness maintaining region B, and the thickness recoverability of the toe region is improved.

  On the other hand, when providing a tow region so that the toe region A penetrates the front and back surfaces of the absorber, an appropriate position of the thickness maintaining region B may be drilled to provide a through hole. The excavation method is not particularly limited, and may be performed by an apparatus used for molding and processing an appropriate absorbent material.

<Method for producing absorber>
The absorbent body of the present invention is formed by laminating the above-described tow region constituting body and the thickness maintaining region constituting body, or arranging the toe region constituting body in an excavation hole formed in the thickness maintaining area constituting body and appropriately bonding them. After being integrated by adhering with an agent or the like, according to a known technique, it can be appropriately cut into a size and individually packaged with a known liquid-permeable sheet. After the tow region structure and the thickness maintaining region structure are stacked and laminated without bonding the toe region structure and the thickness maintaining region structure, or in the excavation hole formed in the thickness maintaining region structure After the constituents are arranged, they can be manufactured by appropriately cutting according to a known technique. Further, it may be individually packaged with a known liquid-permeable sheet or the like.

  When the tow region and the thickness maintaining region have a laminated structure, the fiber material constituting the thickness maintaining region made of pulp or the like and the superabsorbent polymer are towed with a known fiber stacking device or layering device. After the fibers are accumulated on the fiber aggregate constituting the region A, it can be appropriately cut and manufactured. It may be individually packaged later.

  In addition, the sheet | seat for individual packaging is not contained in the absorber in this invention. When used in an absorbent article or the like, it may be used in a form surrounded by a liquid-permeable sheet, but such a surrounding sheet is a part not included in the absorbent body of the present invention.

<Method for producing absorbent article>
The absorbent article having the absorbent body of the present invention and the production method thereof will be described below by taking a sanitary napkin as an example. 34 and 35 show a _first form N ₁ of a sanitary napkin having the absorbent body of the present invention. As can be understood from the plan view from the use surface side shown in FIG. 34, the sanitary napkin N ₁ of the first form is a single part in the longitudinal direction of the absorbent article in both the thickness maintenance region B and the toe region A. Furthermore, as shown in FIG. 35 which is a V ₁ -V ₁ cross-sectional view of FIG. 34, the thickness maintaining region B and the toe region A are laminated and the toe region A is positioned on the use surface side. It is a form.

A method for producing this form of sanitary napkin N ₁ is shown in FIG. First, the adhesive G is applied to an appropriate position of use surface side in the thickness maintaining region constituting material band B _O of fiber stacking pulp sheet or the like for construction of the thickness maintaining region B conveyed by the conveyor or the like from the upstream, The tow region constituting material band _AO constituting the tow region A is continuously laminated and bonded. Next, the laminated absorbent band X _O is cut into an appropriate size by the cutters 10 and 10 to form the absorbent bodies X, X. Then conveyed to the surface side of the absorber X (use side) the topsheet material band t _O, downstream with a conveyor or the like while superposed backsheet material band b _O on the back side. Subsequently, the top sheet material band t _O and the back sheet material band b _O are bonded at appropriate intervals by the hot melt bonding apparatuses 11, 11, and appropriately cut by the hot melt bonding portion H to each absorbent article N. _{Get one} . The hot melt adhesive portion constitutes a single portion in the longitudinal direction of the sanitary napkin.

Next, FIGS. 37 and 38 show a second form N ₂ of the sanitary napkin having the absorbent body X of the present invention. As can be understood from the plan view from the use surface side shown in FIG. 37, the sanitary napkin N ₂ of the second form has a thickness maintaining region B that does not reach a single longitudinal part of the absorbent article. The tow region A reaches the single part in the longitudinal direction of the absorbent article. Further, as shown in FIG. 38 which is a V ₂ -V ₂ cross-sectional view of FIG. And the toe region A is positioned on the use surface side.

A method for producing this sanitary napkin N ₂ is shown in FIG. First, the thickness maintenance area configuration agent zone B _X of fiber stacking pulp sheet or the like for construction of the thickness maintaining region B conveyed from the upstream at a conveyor or the like and cut into a suitable size with a cutter 10, 10 Thickness maintaining region constituent materials X _B , X _B ... Are formed and further conveyed downstream. Next, the adhesive G is applied to an appropriate portion on the use surface side of the thickness maintaining region constituent materials X _B , X _B ..., And the tow region constituent material strip A _O constituting the toe region A is continuously laminated. Transport downstream while adhering. Next, the top sheet material band Nt on the front surface side (use surface side) and the back sheet material band Nb on the back surface side of the absorber band X _O in which the toe region component material band A _O is laminated on the thickness maintaining region component material X _B. Are conveyed downstream by a conveyor. Next, the top sheet material band Nt and the back sheet material band Nb are bonded to each other at a suitable interval by a hot melt bonding apparatus and appropriately cut at the hot melt bonding portion to obtain individual absorbent articles N ₂ .

Next, FIGS. 40 and 41 show a third form N ₃ of the sanitary napkin having the absorbent body of the present invention. As can be understood from the plan view from the use surface side shown in FIG. 40, the sanitary napkin N ₃ of the third embodiment has the thickness maintaining region B reaching the single longitudinal portion of the absorbent article N _3. The tow region A is spot-arranged at the center of the thickness maintaining region B, and as shown in FIG. 41 which is a V ₃ -V ₃ sectional view of FIG. 40, the thickness maintaining region B The tow region A surrounded by the crepe paper C is laminated and positioned on the use surface side. A part of the manufacturing method of the third embodiment is shown in FIG. First, applying the adhesive G at an appropriate position of use surface side of the crepe paper band C _O conveyed from upstream. Next, a tow region constituent material band A _O having a narrower width than that of the crepe paper band C _O is continuously superimposed on the use surface side, and conveyed downstream. Thereafter, the folding device 12 at crepe paper band C both sides surrounded to the absorber constituting material bands toe region constituting material zone A _O folded over the use surface side in crepe paper band toe region constituting material zone A _O of _O Form. And thereafter cutting the absorbent structure material strip to a suitable size and absorbent structure material A _X. Then, although not shown, or to place the absorbent structure material A _X to use surface side of a suitable size Thickness maintaining region structure material, or by cutting after placed on the use surface side in the thickness maintaining region constituting material strip The absorber X is manufactured. Thereafter, the top sheet material band is superimposed on the front surface side (use surface side) of the absorbent body X, and the back sheet material band is overlapped on the back surface and conveyed downstream by a conveyor. Further, the top sheet material band Nt and the back are conveyed at an appropriate interval. The sheet material band Nb is bonded with a hot melt bonding apparatus, and cut with the hot melt bonding portion to obtain individual absorbent articles N ₃ .

<Others>
The specific size, thickness rigidity, etc. of the absorbent body of the present invention are not particularly limited, and can be appropriately changed in design according to the type of absorbent article to be incorporated.

  The present invention is suitable for absorbent bodies of body fluid absorbent articles such as paper diapers and sanitary napkins, but can be applied to other uses within the scope of the present invention.

It is a top view which shows the 1st form of an absorber roughly. It is a top view which shows the 2nd form of an absorber roughly. It is a top view which shows the 3rd form of an absorber roughly. It is a top view which shows roughly the 4th form of an absorber. It is a top view which shows the 5th form of an absorber roughly. It is a top view which shows the 6th form of an absorber roughly. It is a top view which shows roughly the 7th form of an absorber. It is a top view which shows the 8th form of an absorber roughly. It is a top view which shows roughly the 9th form of an absorber. It is a top view which shows roughly the 10th form of an absorber. It is sectional drawing which shows roughly the 11th form of an absorber. It is sectional drawing which shows roughly the 12th form of an absorber. It is sectional drawing which shows roughly the 13th form of an absorber. It is sectional drawing which shows roughly the 14th form of an absorber. It is sectional drawing which shows roughly the 15th form of an absorber. It is sectional drawing which shows roughly the 16th form of an absorber. It is sectional drawing which shows roughly the 17th form of an absorber. It is sectional drawing which shows roughly the 18th form of an absorber. It is sectional drawing which shows roughly the 19th form of an absorber. It is sectional drawing which shows roughly the 20th form of an absorber. It is sectional drawing which shows the 21st form of an absorber roughly. It is sectional drawing which shows roughly the 22nd form of an absorber. It is sectional drawing which shows roughly the 23rd form of an absorber. It is sectional drawing which shows roughly the 24th form of an absorber. It is sectional drawing which shows roughly the 25th form of an absorber. It is a top view which shows roughly the 26th form of an absorber. It is VV sectional drawing of the 26th form of an absorber. It is sectional drawing which shows roughly the 27th form of an absorber. It is sectional drawing which shows schematically the 28th form of an absorber. It is sectional drawing which shows roughly the 29th form of an absorber. It is sectional drawing which shows roughly the 30th form of an absorber. It is the schematic which shows the manufacturing method of the fiber assembly of a laminated structure. It is the schematic which shows the manufacturing method in the case of juxtaposing several fiber aggregates in the width direction. It is a top view which shows roughly the 1st form of the sanitary napkin which has the absorber of this invention. It is sectional drawing which shows schematically the 1st form of the sanitary napkin which has the absorber of this invention. It is the schematic for demonstrating the manufacturing method of the 1st form of the sanitary napkin which has the absorber of this invention. It is a top view which shows roughly the 2nd form of the sanitary napkin which has the absorber of this invention. It is sectional drawing which shows schematically the 2nd form of the sanitary napkin which has the absorber of this invention. It is the schematic for demonstrating the manufacturing method of the 2nd form of the sanitary napkin which has the absorber of this invention. It is a top view which shows roughly the 3rd form of the sanitary napkin which has the absorber of this invention. It is sectional drawing which shows schematically the 3rd form of the sanitary napkin which has the absorber of this invention. It is the schematic for demonstrating the manufacturing method of the 3rd form of the sanitary napkin which has an absorber of this invention.

Explanation of symbols

  A ... Toe region, B, B '... Thickness maintenance region, e ... Emboss, S ... Second sheet, X ... Absorber. t: liquid-permeable top sheet, b: liquid-impervious back sheet, H: adhesive portion.

Claims (11)

  An absorbent body comprising: a tow region composed of a fiber assembly made of tow; and a thickness maintaining region made of an absorbent material other than tow and having a smaller compression work (WC) than the tow region.   The absorbent body according to claim 1, wherein the thickness maintaining region is made of a material containing at least one of pulp fiber, porous foam material, cotton fiber, and nonwoven fabric.   The absorber according to claim 1 or 2, wherein the toe region and the thickness maintaining region have a laminated structure.   The absorber according to claims 1 to 3, wherein the toe region extends along the longitudinal direction at a central portion in the width direction within a range not reaching the peripheral portion.   The absorber according to any one of claims 1 to 4, wherein the tow region is exposed on at least the front and back surfaces.   The absorber according to any one of claims 1 to 5, wherein the tow region is exposed on at least the front and back surfaces of the absorber, and the exposed portion is formed to be bulkier than other portions.   The absorber according to any one of claims 1 to 6, wherein the thickness maintaining region includes a recess, and the toe region is located in the recess.   The absorber according to claim 1, wherein the thickness maintaining region has a laminated structure. The absorber according to claim 1, wherein the density of the toe region is in the range of 10 to 100 kg / m ³ and the density of the thickness maintaining region is in the range of 10 to 100 kg / m ³ .   The absorbent according to any one of claims 1 to 9, wherein the tow is cellulose acetate tow.   The absorbent article according to any one of Claims 1 to 10, wherein the fiber assembly is a structure in which fibers are joined together by dots, lines or spots.

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