JP2005312601A - Absorbent article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an absorbent article which has a surface sheet having a soft texture, having a superior wearing property, eliminating backward flow of liquid, having a sufficient strength of not being broken in use, and eliminating leakage of high absorbent polymer. <P>SOLUTION: This absorbent article is provided with a liquid permeable surface sheet, a liquid impermeable back sheet and an absorbent body disposed between the both sheets. The liquid permeable surface sheet is formed by thermally embossedly compressing at least two short fiber non-woven fabrics, the area of the embossed compression part accounts for 6-28% of the area of the nonwoven fabric, the basis weight is 12-49 g/m<SP>2</SP>, the thickness measured under the pressure of 1.44 kPa is 0.28-0.60 mm, and at least the outermost layer is formed of a hydrophilic non-woven fabric. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to absorbent articles such as disposable diapers and sanitary napkins. More specifically, the present invention has a soft texture, soft and comfortable to wear, has no liquid reversal, has sufficient strength that does not break during use, and causes leakage of the superabsorbent polymer. The present invention relates to an absorbent article having a surface sheet having no surface.

  Absorbent articles such as disposable diapers and sanitary napkins are basically formed from a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber disposed between the front and back sheets. Urine and other excretions excreted at the time of wearing are held on the absorbent body via a liquid-permeable surface sheet, and the liquid-impermeable back sheet prevents the excrement from leaking out of the absorbent article. It has a structure. Various forms have been proposed so that they can be suitably used according to their use, and are widely used by infants and other adult incontinent persons.

  In general, the surface sheet of an absorbent article is formed from a nonwoven fabric, has been subjected to a hydrophilization treatment and has been imparted with hydrophilicity, is soft and has a good feeling of wear, does not revert liquid such as urine, and can be torn during use. It is required to have a sufficient strength without any leakage and a denseness that does not cause leakage of a superabsorbent polymer (hereinafter, simply referred to as “SAP”) that is a constituent of the absorber.

  In addition, the nonwoven fabric can be produced by mixing short fibers with different melting points and tangling the short fiber laminated web opened by a card machine. The spunbond method that entangles the web collected on the collecting net conveyor, the melt blow method that entangles the thermoplastic polymer that is ejected from the nozzle hole by the high-speed air flow that is ejected together, and is collected on the moving net. Although there are various methods, the entanglement treatment is generally performed by thermocompression bonding with a heating roll composed of an embossing roll and a flat roll.

  However, the surface sheet made of a nonwoven fabric manufactured by a conventional method has a problem that the strength is sufficient, but it becomes hard and the feeling of wearing is inferior. In this case, if the nonwoven fabric is thinned, it becomes soft and the wearing feeling is improved. As described above, the surface sheet is required to maintain both characteristics of having a good wearing feeling and having a sufficient strength not torn during wearing.

As a method for improving the problems of these conventional surface sheets, an absorbent article (for example, a composite long-fiber nonwoven fabric formed by heat-embossing compression of composite long-fibers composed of two-component thermoplastic resins having different melting points (for example, Patent Document 1), a bulky nonwoven fabric (for example, Patent Document 2) formed by thermocompression bonding a nonwoven fabric laminate with an embossing roll having a flat portion having a diameter larger than the embossed stamped portion on both outer sides of the embossed stamped portion, or In addition, an absorbent article (for example, Patent Document 3) having a surface sheet formed by heat-sealing a two-layer nonwoven fabric of a surface layer and a back layer and making the density of the surface layer lower than the density of the back layer is disclosed. .
JP 2000-355866 A Japanese Patent Laid-Open No. 2000-167762 Japanese Unexamined Patent Publication No. 64-20844

However, in the above conventional method for producing a surface sheet, since a long fiber nonwoven fabric is used, the strength of the formed surface sheet is sufficient, but it is not necessarily sufficient for improving the texture and softness, The wear feeling is still inferior.
The present invention improves the above-mentioned problems of the conventional absorbent article, has a soft texture, is soft and excellent in feeling of wear, does not revert liquid such as urine, and has sufficient strength not to be broken during use. And an absorbent article having a surface sheet that does not cause SAP leakage.

  The present invention for solving the problems of the conventional absorbent article includes the following inventions.

(1) In an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber disposed between the two sheets,
The liquid-permeable surface sheet is formed by hot embossing pressure bonding of at least two short fiber nonwoven fabrics, the area of the embossing pressure-bonding portion occupying the area of the nonwoven fabric is 6 to 28%, and the basis weight is 12 to 49 g / m ² and a thickness measured under a pressure of 1.44 kPa is 0.28 to 0.60 mm, and at least the uppermost layer is formed of a hydrophilic non-woven fabric. .

(2) The liquid-permeable top sheet has a machine direction (longitudinal) elongation of 12% or more and a cross direction (lateral direction) elongation of 40% or more in a standard state measured according to JIS L 1906. And the tensile strength measured according to JISL1906 is 4.0 N / 50mm or more, The absorbent article as described in (1) description characterized by the above-mentioned.

(3) The liquid-permeable top sheet is subjected to a thermocompression treatment between an embossing roll having irregularities and a smooth roll having a smooth surface that is paired with the embossing roll, or between an embossing roll having a pair of irregularities. The absorbent article according to (1) or (2), wherein the absorbent article is made of a non-woven fabric.

(4) The liquid permeable surface sheet is characterized in that the uppermost layer is made of a hydrophilic non-woven fabric and the other lower layer is made of a hydrophobic non-woven fabric. The absorbent article of Claim 1.

  The surface sheet used in the absorbent article of the present invention uses a short fiber nonwoven fabric, and is formed by heat embossing pressure-bonding a laminate of these in a small area, so it has a soft and soft texture. In addition, by setting the basis weight and thickness to be described later, it is possible to maintain a sufficient strength that does not break when used for absorbent articles and to prevent SAP leakage. Furthermore, by making the uppermost layer hydrophilic and making the lower layer hydrophobic, the permeability of liquid such as urine into the absorber can be improved and the reverse of the once penetrated liquid can be prevented.

In the absorbent article of the present invention, the surface sheet is formed by hot embossing pressure bonding of at least two short fiber nonwoven fabrics.
The area of the embossed crimping portion occupying the area of the nonwoven fabric is 6 to 28%, preferably 16 to 24%, the basis weight is 12 to 49 g / m ² , preferably 16 to 32 g / m ² , and
The thickness measured under a pressure of 44 kPa is 0.28 to 0.60 mm, preferably 0.32 to 0.42 mm, and at least the uppermost layer is formed of a hydrophilic nonwoven fabric, preferably other than the uppermost layer This layer is formed of a hydrophobic nonwoven fabric.

  Moreover, the surface sheet in the absorbent article of the present invention has an elongation percentage in the machine direction (longitudinal direction) of 12% or more, preferably 15 to 30% in the standard state measured according to JIS L 1906. Non-woven fabric having an elongation in the transverse direction) of 40% or more, preferably 45 to 80%, and a tensile strength measured according to JIS L 1906 of 4.0 N / 50 mm or more, preferably 5 to 47 N / 50 mm. By using, the effect of the absorptive article of the present invention can be raised more.

  Hereinafter, although the material used in this invention is demonstrated, this invention is not restrict | limited at all by these.

<Liquid permeable surface sheet>
In the present invention, as the surface sheet, a nonwoven fabric made of polypropylene, polyethylene, polyester fiber or the like which is a short fiber having a fineness of 6 dtex or less, preferably 1.2 to 4.6 dtex is used. Moreover, you may use the nonwoven fabric which consists of a short fiber of 2 or more components composite fibers, such as polyester, a polypropylene, and polyethylene, and composite fibers, such as low melting point polyester / polyester, polyester / polyethylene, polypropylene / polyethylene, are preferable from the surface of intensity | strength. However, there are no particular restrictions.

The surface sheet in the absorbent article of the present invention is formed by heat embossing pressure-bonding a laminate of at least two nonwoven fabrics formed of the above short fibers. In this case, the area of each hot embossed crimping portion is 0.03 to 16 mm ² , preferably 0.5 to 12 mm ² , and the total area of the hot embossed crimping portion in the area of the nonwoven fabric is 6 to 28%, Preferably it is 16 to 24%.
If the area of the individual heat embossing crimping portion is less than 0.03 mm ^2, the adhesive strength between the nonwoven fabric becomes weak, also becomes wider than the 16 mm ^2, so that wearing feeling becomes hard and inferior. Further, when the total area of the heat embossed crimping portion occupying the area of the nonwoven fabric is less than 6%, the adhesive strength between the nonwoven fabrics is reduced, and when the total area exceeds 26%, the strength between the nonwoven fabrics is increased, but the texture is hard. The wear feeling becomes inferior.

  Moreover, the heat embossing press-bonding treatment of the nonwoven fabric is performed by a thermocompression-bonding roll comprising an embossing roll having irregularities and a smooth roll having a smooth surface paired with the embossing roll, or a thermocompression bonding comprising an embossing roll having a pair of irregularities Can be done by roll. Moreover, the shape of the convex part of an embossing roll can use what was engraved in various shapes, for example, the planar shape of a convex part front end surface is circular, an ellipse, a square, a rectangle, a parallelogram, a rhombus Various shapes such as triangles, hexagons, and the like can be used. Among them, a shape having a flat side surface at the tip of the convex portion can be preferably used.

Topsheet of the absorbent article of the present invention, the basis weight of the laminated nonwoven fabric is preferably 12~49g / m ^2, and more preferably 20 to 30 g / m ^2. When the basis weight is less than 12 g / m ^2, the strength of the surface sheet becomes weak, and the SAP is more likely to fall off. On the other hand, when the basis weight is larger than 49 g / m ² , the thickness becomes too thick, so that the feeling of wearing is inferior and the liquid permeability is lowered.

Moreover, the surface sheet in the absorbent article of the present invention has a thickness of 0.28 to 0.60 mm measured under a pressure of 95 g / in ² (1.44 kPa) of the laminated nonwoven fabric, and more preferably is 0.00. 3 to 0.5 mm. When the thickness is less than 0.28 mm, the strength of the surface sheet is weakened, and SAP is more likely to fall off. On the other hand, when the thickness exceeds 0.60 mm, it becomes too thick, so that the feeling of wearing is inferior and the liquid permeability is lowered.
In addition, the thickness of a nonwoven fabric can be measured with the thickness measuring machine (model: 49-70) made from TMI.

  Since the nonwoven fabric forming the surface sheet in the absorbent article of the present invention is usually hydrophobic and cannot be used as it is, at least the uppermost layer that is in contact with the wearer's skin is hydrophilized. Is given. As a method of hydrophilization, a hydrophilic resin or a hydrophilizing agent is mixed or copolymerized with a resin for forming a non-woven fabric to make it hydrophilic, and hydrophilic fine fibers such as pulp are used as the leachate gas when forming the non-woven fabric. Examples thereof include a method of hydrophilizing by containing a hydrophilic fiber in an ultrafine fiber, or a method of hydrophilizing by imparting or copolymerizing a hydrophilic agent after forming a nonwoven fabric.

In the case of the present invention, the non-woven fabric can be subjected to hydrophilic treatment on the uppermost layer as well as other layers, but only the uppermost layer is subjected to hydrophilic treatment so that the other layers are in a hydrophobic state. Thus, it is preferable because it is possible to form a top sheet that is excellent in the permeability of liquid such as urine and that prevents the liquid once permeated from returning.
As the hydrophilic resin, polyethylene terephthalate copolymerized with polyalkylene glycol kneaded with alkylbenzene sulfonic acid soda, hydrophilic polyethylene, etc. can be used, and as the hydrophilizing agent, dialkyl sulfosuccinate is used. Nate-based hydrophilizing agents can be used.

Further, the surface sheet in the absorbent article of the present invention has a machine direction (longitudinal direction) elongation of 12% or more, preferably 15 to 30% in a standard state measured according to JIS P 1906 of the laminated nonwoven fabric. The elongation in the cross direction (lateral direction) is 40% or more, preferably 45 to 80%, and the tensile strength is 4.0 N / 50 mm or more in both the machine direction and the cross direction in a dry state or a wet state. Is 5 to 47 N / 50 mm.
When the elongation percentage and tensile strength of the nonwoven fabric are equal to or higher than these values, it is possible to obtain a surface sheet having a soft texture and sufficient strength that is not torn during wearing.

<Liquid impervious back sheet>
In the absorbent article of the present invention, a liquid-impermeable plastic film is used for the back sheet. The plastic film can be made of, for example, polyethylene, polypropylene, polyvinyl chloride, or similar materials, or materials such as films or sheets based on polyvinyl alcohol. The back sheet material may be transparent or opaque, and the back sheet may be embossed. Furthermore, what stuck the nonwoven fabric, woven fabric, elastic nonwoven fabric, etc. which consist of thermoplastic resins, such as polyethylene, a polypropylene, polyester, can also be used for the said liquid-impermeable plastic film.

<Absorber>
In the present invention, the absorbent body is formed mainly of cotton-like pulp and superabsorbent polymer (SAP). Moreover, you may heat-press by mixing 3-60 mass% heat-fusible substance with respect to cotton-like pulp. The structure of the absorbent body is not particularly limited. For example, the absorbent body may be a single layer mainly composed of cotton-like pulp, or may be a layer-like material in which SAP is uniformly mixed with cotton-like pulp, or cotton-like pulp. A structure in which a uniform layer made of SAP is sandwiched between two layers mainly composed of s.
As the cotton-like pulp, a chemical pulp sheet or a fiber length of 5 mm or less obtained by defibrating a mechanical pulp sheet with a pulverizer is used. As a pulp raw material, hardwood, straw, bamboo, kefna and the like can be used in addition to conifers. Moreover, although the usage-amount of a pulp changes with whether it is used independently, for example, using it individually, using multiple lamination | stacking, or using another absorber together with the target absorber, generally 50-400g. / M ² .

  Examples of the superabsorbent polymer include starch-based, cellulose-based, and synthetic polymer-based polymers. That is, saponified starch-acrylic acid (salt) graft copolymer, starch-ethyl acrylate graft copolymer, saponified starch-methacrylic acid methyl graft copolymer, saponified starch-acrylonitrile graft copolymer , Saponified starch-acrylamide graft copolymer, acrylic acid (salt) polymer, polyethylene oxide cross-linked with acrylic acid, cross-linked product of sodium carboxymethyl cellulose, cross-linked product of polyvinyl alcohol-maleic anhydride reactant Among them, those that absorb urine, body fluids and water more than 20 times their own weight, and sodium polyacrylate are most suitable from the viewpoint of absorption performance.

  The amount of the superabsorbent polymer is 10 to 500% by mass, preferably 15 to 300% by mass, based on the amount of the cotton-like pulp, and the superabsorbent polymer in such an amount is substantially uniformly in the cotton-like pulp. When distributed, when the superabsorbent polymer absorbs liquid and swells, the particles have minimal mutual interference and are less likely to come into continuous contact to form a permeation barrier, resulting in urine and body fluids. Can be transmitted and absorbed well in the three-dimensional direction.

  Moreover, as a heat-fusible substance, when considering mixing with a cotton-like pulp, a fibrous thing is preferable. Examples of the heat-fusible substance include polypropylene, polyethylene, polyester, polyvinylidene, acrylic resin, and nylon resin. Or the composite fiber etc. which consist of 2 or more components, such as polyester, a polypropylene, polyethylene, etc. may be sufficient, and the composite fiber of polyester / polyester, polyester / polyethylene, polypropylene / polyethylene is especially preferable from the surface of intensity | strength. A fineness of about 1 to 5 denier is preferable, and a fiber length of 3 to 30 mm is suitable for mixing with cotton-like pulp, but is not particularly limited. By mixing these with cotton-like pulp and thermocompression bonding at a constant pressure, a skeletal structure with a heat-fusible substance is formed, and it becomes possible to have the strength of the cotton-like pulp layer itself even when wet. The method of thermocompression bonding can be performed by a hot press roll, a hot air dryer, a microwave heater, an infrared heater or the like, but is not particularly limited, and heat is uniformly transmitted to the mat layer, so that heat fusion is possible. Any material that melts and can form a skeleton structure may be used.

  The compression method of the absorbent body may be a continuous surface shape so that the density of the absorbent body becomes substantially uniform over the whole by a roll having a smooth circumferential surface, or the circumferential surface is uneven. Depending on a certain roll or the like, the density of the absorbent body may be partially different, and embossment having a pattern arrangement that guides urine and body fluid in the longitudinal direction and the oblique direction may be used. In the case of embossing, the compression part and the non-compression part may be either continuous or discontinuous.

The absorber may be at least partially covered with water absorbent paper. The water-absorbent paper is mainly made of cellulose pulp made of chemical pulp obtained by bleaching lignocellulose materials such as hardwood and softwood wood chips after cooking without using elemental chlorine. Pulp or dry pulp obtained by dehydrating and drying this slush pulp is used. Moreover, it is preferable that the cellulose pulp which forms a water absorbing paper contains 80-97 mass% of softwood pulp, and 20-3 mass% of hardwood pulp, and also deinked the waste paper as needed. The resulting deinked waste paper pulp or the like can be used.
The water absorbent paper preferably has a basis weight of 10 to 25 g / m ² and a thickness of 0.05 to 0.13 mm. By setting the basis weight and thickness of the water absorbent paper within this range, it is possible to easily obtain an absorbent article having the above-described characteristics.

  Hereinafter, the absorbent article of the present invention will be described in detail with reference to the drawings, taking diapers as examples. However, the present invention is not limited to these examples.

FIG. 1 is a partially cut-out developed plan view of the disposable diaper of the present invention when viewed from the top sheet side.
In FIG. 1, a disposable diaper 1 is basically composed of a liquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and an absorbent body 4 disposed between these two sheets. An elastic member 5 around the waist is disposed at the position of the opening around the waist, an elastic member 6 around the leg is disposed at the position of the opening around the leg, and a fastening tape 8 is attached to the side edge of the side flap 7 on the back body. In addition, a pair of three-dimensional gathers 9 are formed along both side edges of the diaper in the longitudinal direction inside the leg elastic member 6 around the leg.

FIG. 2 is a plan view showing an enlarged state of the top sheet used in the disposable diaper of the present invention.
In FIG. 2, a plurality of hot embossed crimping portions 10 are formed on the top sheet 2.
In addition, in FIG. 2, although the shape of the heat embossing crimping | compression-bonding part 10 showed the thing of elliptical shape, it is not limited to this, Circular, square, a rectangle, a parallelogram, a rhombus, a triangle, a hexagon etc. Various shapes can be used.

FIG. 3 is an enlarged cross-sectional view showing a state in which the topsheet shown in FIG. 2 is cut along line XX.
In FIG. 3, the top sheet 2 is composed of two nonwoven fabrics, an uppermost nonwoven fabric 11 in contact with the wearer's skin and a lower nonwoven fabric 12 disposed under the uppermost nonwoven fabric 11. Processed and formed.
In addition, in FIG. 3, the surface sheet 2 is an example in which two nonwoven fabrics 11 and 12 are formed by hot emboss pressure bonding treatment using a heat pressure bonding roll including an emboss roll and a smooth roll having a smooth surface that is paired with the emboss roll. The hot-embossed crimping portion 10 is formed on the uppermost nonwoven fabric 11.
Further, the top sheet 2 of the present invention can make both the uppermost layer nonwoven fabric 11 and the lower layer nonwoven fabric 12 hydrophilic, but only the uppermost layer nonwoven fabric 11 is made hydrophilic and the lower layer nonwoven fabric 12 is made hydrophobic. This is preferable because it is excellent in the permeability of liquid such as urine and the reverse movement of the liquid once transmitted is prevented.

FIG. 4 is an enlarged cross-sectional view showing a state in which the top sheet shown in FIG. 2 is cut along the line XX, showing an example different from FIG.
In FIG. 4, the top sheet 2 shows an example in which the uppermost layer nonwoven fabric 11 and the lower layer nonwoven fabric 12 are formed by heat embossing pressure bonding with a thermocompression bonding roll formed of an embossing roll having a pair of irregularities. A hot embossed crimping portion 10 is formed on both the lower nonwoven fabric 12 and the lower nonwoven fabric 12.

In the absorbent article of the present invention, the surface sheet is formed by hot-embossing pressure bonding of at least two short fiber nonwoven fabrics, the area of the embossed pressure-bonding portion occupying the area of the nonwoven fabric is 6 to 26%, and the basis weight is The thickness measured under a pressure of 12 to 49 g / m ² and 1.44 kPa is 0.28 to 0.6 mm, and at least the uppermost layer is formed of a hydrophilic nonwoven fabric.
The absorbent article of the present invention having a surface sheet formed of a nonwoven fabric having such a structure has a soft texture, is soft and excellent in wearing feeling, does not revert liquid, and does not break when used. It has high strength and does not cause SAP leakage, and is useful as an absorbent article for adult incontinent persons including infants.

It is a partial notch expansion | deployment top view at the time of seeing the disposable diaper of this invention from the surface sheet side. It is the fragmentary figure which expands and shows a part of plane of the surface sheet of this invention. It is a cross-sectional enlarged view which shows the state which cut | disconnected the surface sheet shown in FIG. 2 along the XX line. It is a cross-sectional enlarged view which shows the state which cut | disconnected the surface sheet shown in FIG. 2 along the XX line which shows the example different from FIG.

Explanation of symbols

1: Disposable diaper (absorbent article)
2: Liquid-permeable top sheet 3: Liquid-impermeable back sheet 4: Absorber 5: Elastic elastic member around the waist 6: Elastic elastic member around the leg 7: Side flap 8: Fastening tape 9: Solid gather 10: Heat Embossed crimping part 11: Uppermost layer nonwoven fabric 12: Lower layer nonwoven fabric

Claims (4)

In an absorbent article having a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body disposed between the two sheets,
The liquid-permeable surface sheet is formed by hot embossing pressure bonding of at least two short fiber nonwoven fabrics, the area of the embossing pressure-bonding portion occupying the area of the nonwoven fabric is 6 to 28%, and the basis weight is 12 to 49 g / m ² and 1.44 kPa Thickness measured under pressure of 0.28-0.60
mm, and at least the uppermost layer is formed of a hydrophilic nonwoven fabric.   The liquid-permeable top sheet has an elongation of 12% or more in the machine direction (longitudinal direction) in a standard state measured according to JIS L 1906, and an elongation of 40% or more in the cross direction (lateral direction). And the tensile strength measured according to JISL1906 is 4.0 N / 50mm or more, The absorbent article of Claim 1 characterized by the above-mentioned.   The liquid-permeable surface sheet is formed by thermocompression bonding between an embossing roll having unevenness and a smooth roll having a smooth surface that is paired with the embossing roll, or between a pair of embossing rolls having unevenness. The absorbent article according to claim 1, wherein the absorbent article is made of a non-woven fabric.   4. The liquid-permeable surface sheet according to claim 1, wherein the uppermost layer is made of a hydrophilic non-woven fabric, and the other lower layer is made of a hydrophobic non-woven fabric. 5. Absorbent articles.

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