JPH09299403A - Briefs type disposable diaper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a briefs type disposable diaper which makes a user feel comfortable in wearing with excellent touch on skin and texture and lower in skin irritability. SOLUTION: This disposable diaper is provided with a liquid permeable surface sheet 11, a liquid impermeable rear sheet 12, and a body having a liquid holding absorbing material interposed between both the sheets and a pair of stretch side panels 20. The pair of stretch side panels 20 are arranged between a waist opening part 15 and a pair of leg opening parts 22 and elastic members forming a gathering are attached on the respective peripheries of the waist opening part 15 and the pair of leg opening parts 22. In this case, the stretch side panel 20 contains an elastic conjugate fiber including an elastic polyolefin and other polyolefin differing from the elastic polyolefin. A sheet containing nonwoven cloth with a permanents distortion of at most 60% and a hysteresis ratio of at most 6.0 is used.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pants-type disposable diaper for infants, incontinent persons, and adults.

[0002]

2. Description of the Related Art Pants-type disposable diapers are characterized in that they can be raised and lowered by the wearer like ordinary underwear, as compared with flat type (expandable) disposable diapers. However, in order to prevent the wearer from leaking excrement and to be able to wear it easily, the pants-type disposable diaper is required to have a good fit property. It is required to have sufficient followability even for various activities. In order to meet such demands, there has been proposed a pants-type disposable diaper in which a stretchable side panel is provided on a side portion of the main body of the pants-type disposable diaper which is bonded to the abdominal portion and the back portion.

A stretchable nonwoven fabric or the like is generally used as the material of the side panel. The above-mentioned non-woven fabric is generally produced from elastic fibers obtained by processing a thermoplastic elastomer into a fibrous shape. However, only the direct sheet method can be used for the production method, and the production method is limited. In addition, the stretchable nonwoven fabric produced by the direct sheet method has a drawback that it has a peculiar touch and skin irritation to rubber, and the texture and the like are still insufficient.

Accordingly, an object of the present invention is to provide a pants-type disposable diaper which is excellent in touch and feel, has low skin irritation, and has a comfortable wearing feeling.

[0005]

Means for Solving the Problems As a result of intensive investigations by the present inventors, it was found that the above object can be achieved by using a sheet containing a nonwoven fabric formed of specific elastic composite fibers as a stretchable side panel. did.

[0006] The present invention has been made based on the above findings, and includes a liquid-permeable top sheet, a liquid-impermeable back sheet,
And a main body having a liquid-retaining absorber interposed between these sheets and a pair of elastic side panels, wherein the pair of elastic side panels are respectively provided between the waist opening and the pair of leg openings. In the pants-type disposable diaper in which the waist opening and the pair of leg openings are each provided with an elastic member that forms a gather, in the waist opening and the pair of the leg openings, as the elastic side panel, A sheet containing an elastic composite fiber comprising an elastic polyolefin and another polyolefin different from the elastic polyolefin, and a nonwoven fabric having a permanent set of 60% or less and a hysteresis ratio of 6.0 or less. The above object is achieved by providing a pants-type disposable diaper characterized by using.

[0007]

The pants-type disposable diaper according to the present invention has stretchable side panels, and since the stretchable side panels are made of a sheet containing a non-woven fabric having a cloth-like feel, they are excellent in touch and texture and have no skin irritation. It will be low and comfortable to wear.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the pants-type disposable diaper of the present invention will be described below with reference to the drawings. Here, FIG. 1 is a perspective view showing a preferred embodiment of the pants-type disposable diaper of the present invention, and FIG.
It is a partially broken development view of the disposable diaper shown in FIG.

The pants-type disposable diaper 1 of this embodiment shown in FIGS. 1 and 2 has a liquid-permeable top sheet 11, a liquid-impermeable back sheet 12, and a liquid-retaining property interposed between these sheets. A main body 10 having an absorber 13 is provided. The body 10 is divided into an abdomen C located on the abdomen of the wearer, a back A located on the back, and a crotch part B when worn. The absorber 13 has a rectangular shape, and the top sheet 11 and the back sheet 1 are
It is clamped and fixed by 2 and.

Stretchable side panels 20, 20 'are joined and fixed to the left and right edges of the ventral side portion C and the back side portion A, respectively. The joining and fixing of the side edge portions and the stretchable side panels 20, 20 'can be performed by heat sealing, ultrasonic sealing, sealing with an adhesive, or any other suitable means.

Elastic side panels 20 on the ventral side C,
20 and the elastic side panels 20 ', 2 of the back side A
0 ′ respectively contact the surface sheet side of the elastic side panel 20 and the surface sheet side of the elastic side panel 20 ′ to form a seal portion 31, and the seal portion 3
It is joined and fixed via 1. As a result, the waist opening 15 and the pair of left and right leg openings 17 and 17 'are formed. That is, the elastic side panels 20, 2
0'is one elastic side panel which is joined and fixed by the sealing portion 31 to be integrated, and the elastic side panel is arranged between the waist opening and the pair of leg openings. There is. The joining and fixing in the seal portion 31 can be performed by heat sealing, ultrasonic sealing, sealing with an adhesive, or any other suitable means.

In the ventral side portion C and the back side portion A,
In the vicinity D of the waist opening, a belt-shaped waist elastic member 2
3, 23 'are arranged parallel to the edge of the waist opening, that is, the front and rear waist portions 14, 14'. In the waistline portion E, which is located around the wearer's waistline when worn, four thread-shaped waistline elastic members 21 and 21 'are provided in each of the abdominal portion C and the dorsal portion A, and the front and rear waist portions 1 are provided.
It is arranged in parallel with 4, 14 'so as to be sandwiched between the back sheet 12 and the absorber 13. The waist elastic members 21 and 21 'and the waist elastic member 2
By the arrangement of 3,23 ', the ventral side portion C
And the back side part A is the outer peripheral surface of the part which abuts on the waist and waist of the wearer in the pants-type disposable diaper 1 via the elastic side panels 20 and 20 '(the waist opening vicinity D and the waist part E). Main back sheet 1
2), gathers are formed.

Leg body elastic members 22, 22 'are disposed on both left and right sides of the main body, and the pair of leg opening portions 1 are formed by the leg body elastic members 22, 22'.
Gathers are formed on the peripheral portions of 7, 17 'so that they can fit in the crotch region.

Further, as shown in FIGS. 1 and 2, the back sheet 12 is provided in the back side portion A at a substantially central portion thereof.
A disposal tape 30 is provided on the surface of the. By using the disposal tape 30, after the bowel movement or the like, the diaper body can be rolled and stopped compactly with the disposal tape 30 to be discarded, so that the bowel movement can be confined in the diaper body and treated hygienically. And it is easy to dispose.

Next, materials and the like of the respective constituent members of the pants-type disposable diaper of this embodiment will be described. The surface sheet 11 is preferably a liquid-permeable sheet that allows excrement to permeate into the absorbent body 13 and has a feeling close to that of underwear. Examples of such a liquid-permeable sheet include woven cloth, nonwoven cloth, and porous material. A film or the like is used.

As the back sheet 12, a liquid-impermeable and vapor-permeable film sheet obtained by adding a filler to a thermoplastic resin and stretching, or a laminate of a fiber assembly and the film sheet is used.

The absorbent 13 is preferably made of defibrated pulp as a main material and a high-molecular water-absorbing polymer in combination. The high-molecular water-absorbing polymer is an upper layer of the absorber 13,
It may be present in any position of the middle layer and the lower layer, or may be a mixture with pulp. The high molecular weight water-absorbing polymer is preferably in the form of particles having a holding performance capable of absorbing and holding a liquid 20 times or more its own weight and having a gelling property. Examples of such a high-molecular water-absorbing polymer include starch-acrylic acid (salt) graft copolymer, saponified starch-acrylonitrile copolymer, and sodium carboxymethyl cellulose cross-linked product.
Acrylic acid (salt) polymers and the like are preferable.

The waist elastic members 23, 23 ', the waist elastic members 21, 21', and the leg elastic members 2
2, 22 'include natural rubber, synthetic rubber,
An elastic body such as a thread-shaped, band-shaped, or film-shaped foam made of an ethylene-α-olefin copolymer elastomer produced by using a polyurethane or a metallocene catalyst can be used without particular limitation.

As the discarding tape 30, an ordinary tape material coated with an adhesive material is preferably used.
The pressure-sensitive adhesive may be an ordinary pressure-sensitive adhesive such as styrene-
A hot-melt resin or emulsion of a butadiene block copolymer, a styrene-isoprene block copolymer, an acrylic ester, an acrylic copolymer, vinyl acetate, an ethylene-vinyl acetate copolymer, etc. is used.

The characteristic parts of the pants-type disposable diaper 1 of the present embodiment will now be described. The stretchable side panels 20, 20 'include elastic polyolefin and another polyolefin different from the elastic polyolefin. It contains elastic composite fiber and has a permanent set of 6
It is composed of a sheet containing a non-woven fabric having a hysteresis ratio of 0% or less and 6.0 or less. The non-woven fabric has a cloth-like feel like an ordinary non-woven fabric, is excellent in texture, and has low skin irritation. Therefore, the pants-type disposable diaper 1 using the sheet containing the nonwoven fabric as the stretchable side panels 20, 20 ′ has a comfortable wearing feeling.

The elastic polyolefin contained in the elastic composite fiber has a permanent set of preferably 50% or less, more preferably 0 to 30%, and a hysteresis ratio of preferably 5.0 or less, more preferably 1.0. ~ 3.5 is an elastic polyolefin. When the permanent set exceeds 50% or the hysteresis ratio exceeds 5.0,
It is not preferable because the elastic composite fiber obtained has a reduced crimpability and the elasticity of the elastic composite fiber as an elastic fiber decreases.

The permanent strain and the hysteresis ratio are measured as follows, respectively. The strain and the hysteresis ratio of the elastic polyolefin are measured by using the elastic polyolefin formed into a sheet as a sample. Measuring method of permanent set;
The sample is set to 1 in the same manner as the measurement method of the hysteresis ratio below.
The length of the sample at the time of the initial chuck distance after being stretched by 00% was measured, and the length that cannot be relaxed with respect to the initial length (initial chuck distance) when stretched by 100% (extended from the initial length (Length of lengthened portion) ratio (%)
Was obtained, and this was set as permanent set. Hysteresis ratio measurement method: In order to examine the elasticity of each sample, the hysteresis ratio was measured using an elongation tester with an integrating device. That is, a sample having a width of 25 mm was prepared from the elastic polyolefin, the sample was fixed to the tester so that the chuck distance was 100 mm, and then each sample was stretched 100% at a speed of 300 mm / min. Create a stretching curve, then loosen at the same speed and stop loosening when the chuck length reaches the initial length to create a relaxation curve, measure the area under the stretching curve and the area under the relaxation curve, respectively. By substituting
The hysteresis ratio was calculated. Hysteresis ratio = area under stretch curve / area under relaxation curve Here, since the true elastomer has a hysteresis ratio of 1.0, an elastic polyolefin having a hysteresis ratio of less than 5 is measured when the hysteresis ratio of the sample is measured. The elastic composite fiber possessed is suitable as an elastic material for hygiene products.

The density of the elastic polyolefin is preferably 0.90 g / cm ³ or less, and is 0.88.
More preferably, it is 0 to 0.860 g / cm ³ . If the density exceeds 0.90 g / cm ³ , the tensile strength and the feeling (fitness) decrease, which is not preferable. Here, the density is measured in the same manner as in the measurement of the density of a known polymer.

As the elastic polyolefin, as described above, those satisfying the permanent strain and the hysteresis ratio within the above range and further satisfying the above density are preferable. Specifically, a cyclopentadienyl complex is used as a catalyst. Preferable examples include ethylene-α / olefin copolymers obtained by copolymerization.

Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1
-Octene, 1-heptene, 4-methylpentene-1,
4-methylhexene-1,4-dimethylpentene-1,
Examples thereof include α-olefins having 3 to 20 carbon atoms such as octadecene, isooctene, isooctadiene and decadiene, and among them, 1-hexene, 1-octene, 1-heptene and 4-methylpentene-1 are preferable. Further, these α-olefins can be copolymerized with ethylene in one kind or in two or more kinds.

The copolymerization ratio of the α-olefin is preferably 2 to 60% by weight based on the total weight of the copolymer. That is, it is preferable that the blending amount of the α-olefin is 2 to 60% by weight based on the total amount of ethylene and the α-olefin, and the copolymerization is performed. When the copolymerization ratio is less than the above lower limit or more than the above upper limit, the elasticity of elasticity becomes low.

Examples of the cyclopentadienyl complex used as a catalyst include compounds represented by the following formula (I). ML _X (I) wherein M is a transition metal selected from the group consisting of Zr, Ti, Hf, V, Nb, Ta and Cr, and L is
A ligand having a cyclopentadienyl skeleton, which is a ligand coordinating to the transition metal, having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an allyloxy group having 1 to 12 carbon atoms, and having 1 to 1 carbon atoms.
2 represents a trialkylsilyl group, a SO ₃ R group (where R is a hydrocarbon group having 1 to 8 carbon atoms which may have a substituent such as halogen), a halogen atom or a hydrogen atom, and x
Is the same number as the valence of the above transition metal. However, the above L
May be different groups when two or more are coordinated, but at least one is a group having a cyclopentadienyl skeleton. That is, when the above x is 1,
L is a group having a cyclopentadienyl skeleton,
When x is 2 or more, at least one of the plurality of L is a group having a cyclopentadienyl skeleton. ]

Examples of the group having a cyclopentadienyl skeleton include cyclopentadienyl group, methylcyclopentadienyl group, dimethylcyclopentadienyl group, trimethylcyclopentadienyl group, tetramethylcyclopentadienyl group. Enyl group, pentamethylcyclopentadienyl group, ethylcyclopentadienyl group, methylethylcyclopentadienyl group, propylcyclopentadienyl group, methylpropylcyclopentadienyl group,
Alkyl-substituted cyclopentadienyl groups such as butylcyclopentadienyl group, methylbutylcyclopentadienyl group, hexylcyclopentadienyl group; or indenyl group, 4,5,6,7-tetrahydroindenyl group, fluorenyl A group etc. can be illustrated. Further, these groups may be substituted with a halogen atom, a trialkylsilyl group or the like.

As the group having a cyclopentadienyl skeleton, an alkyl-substituted cyclopentadienyl group is particularly preferable among the above-exemplified groups.

When the compound represented by the general formula (I) contains two or more groups having a cyclopentadienyl skeleton, the two groups having a cyclopentadienyl skeleton among them are: It may be bonded via an alkylene group such as ethylene and propylene; a substituted alkylene group such as isopropylidene and diphenylmethylene; a silylene group or a substituted silylene group such as a dimethylsilylene group, a diphenylsilylene group, and a methylphenylsilylene group.

Examples of the hydrocarbon group having 1 to 12 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group and an aralkyl group. More specifically, the alkyl group is a methyl group, Ethyl group, propyl group,
Examples include isopropyl group and butyl group, examples of cycloalkyl group include cyclopentyl group and cyclohexyl group, examples of aryl group include phenyl group and tolyl group, and examples of aralkyl group include benzyl group and neophyll group. Examples include groups. Examples of the alkoxy group include methoxy group, ethoxy group, butoxy group, etc., examples of the aryloxy group include phenoxy group, etc., and examples of the halogen atom include fluorine, chlorine, bromine, iodine and the like.

Examples of the SO ₃ R group include p-toluenesulfonato group, methanesulfonato group, trifluoromethanesulfonato group and the like.

As the compound containing a group having such a cyclopentadienyl skeleton, for example, when the valence of the transition metal is 4, it is more specifically represented by the following formula (II).

R ² _k R ³ _l R ⁴ _m R ⁵ _n M (II) [wherein, M is the above transition metal, and R ² is a group having a cyclopentadienyl skeleton (ligand ), And R ³ , R
⁴ and R ⁵ are each a group having a cyclopentadienyl skeleton, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a trialkylsilyl group, a SO ₃ R group, a halogen atom or a hydrogen atom. Where k is an integer greater than or equal to 1, and k + 1 + m
+ N = 4. ]

In the present invention, in the above formula (II), R
^A compound in which at least two of ² , R ³ , R ⁴ and R ⁵ , for example, R ² and R ³ are groups (ligands) having a cyclopentadienyl skeleton is preferably used. The skeleton-bearing groups (eg R ² and R ³ ) may be attached as described above.

Specific examples of the above cyclopentadienyl complex in which M is zirconium will be shown below. Bis (indenyl) zirconium dichloride, bis (indenyl) zirconium dibromide, bis (indenyl) zirconium bis (p-toluenesulfonato) bis4,5,6,7-tetrahydroindenyl) zirconium dichloride, bis (fluorenyl) zirconium dichloride , Ethylenebis (indenyl) zirconium dichloride, ethylenebis (indenyl) zirconium dibromide, ethylenebis (indenyl) dimethylzirconium, ethylenebis (indenyl) diphenylzirconium, ethylenebis (indenyl) methylzirconium monochloride, ethylenebis (indenyl) zirconium Bis (methanesulfonato), ethylenebis (indenyl) zirconium bis (p-toluenesulfonato),
Ethylene bis (indenyl) zirconium bis (trifluoromethane sulfonate), ethylene bis (4,5,5
6,7-Tetrahydroindenyl) zirconium dichloride, isopropylidene (cyclopentadienyl-fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl-methylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (cyclopentadienyl) Zirconium dichloride, dimethyl silylene bis (methylcyclopentadienyl) zirconium dichloride, dimethyl silylene bis (dimethyl cyclopentadienyl) zirconium dichloride, dimethyl silylene bis (trimethylcyclopentadienyl) zirconium dichloride, dimethyl silylene bis (indenyl) zirconium dichloride , Dimethylsilylene bis (indenyl) zirconium bis (trifluoromethanesulfonato), di Chirushirirenbisu (4,
5,6,7-Tetrahydroindenyl) zirconium dichloride, dimethylsilylenebis (cyclopentadienyl-fluorenyl) zirconium dichloride, diphenylsilylenebis (indenyl) zirconium dichloride, methylphenylsilylenebis (indenyl) zirconium dichloride, bis (cyclopenta) Dienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, bis (cyclopentadienyl)
Methylzirconium monochloride, bis (cyclopentadienyl) ethylzirconium monochloride, bis (cyclopentadienyl) cyclohexylzirconium monochloride, bis (cyclopentadienyl) phenylzirconium monochloride, bis (cyclopentadienyl)
Benzyl zirconium monochloride, bis (cyclopentadienyl) zirconium monochloride, bis (cyclopentadienyl) methylzirconium monohydride, bis (cyclopentadienyl) dimethylzirconium, bis (cyclopentadienyl) diphenylzirconium, Bis (cyclopentadienyl) dibenzylzirconium, bis (cyclopentadienyl)
Zirconium methoxy chloride, bis (cyclopentadienyl) zirconium ethoxy chloride, bis (cyclopentadienyl) zirconium bis (methanesulfonato), bis (cyclopentadienyl) zirconium bis (p-toluenesulfonato), bis (cyclo Pentadienyl) zirconium bis (trifluoromethanesulfonato), bis (methylcyclopentadienyl) zirconium dichloride, bis (dimethylcyclopentadienyl)
Zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium ethoxy chloride, bis (dimethylcyclopentadienyl) zirconium bis (trifluoromethanesulfonate), bis (ethylcyclopentadienyl) zirconium dichloride, bis (methylethylcyclopentadiene) (Enyl) zirconium dichloride, bis (propylcyclopentadienyl) zirconium dichloride, bis (methylpropylcyclopentadienyl)
Zirconium dichloride, bis (butylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium bis (methanesulfonato), bis (trimethylcyclopentadienyl) ) Zirconium dichloride, bis (tetramethylcyclopentadienyl) zirconium dichloride,
Bis (pentamethylcyclopentadienyl) zirconium dichloride, bis (hexylcyclopentadienyl)
Zirconium dichloride, bis (trimethylsilylcyclopentadienyl) zirconium dichloride.

In the above-exemplified compounds, disubstituted cyclopentadienyl rings such as dimethylcyclopentadienyl include 1,2- and 1,3-substituted compounds,
Trisubstituted compounds such as dimethylcyclopentadienyl are 1,2,2
Includes 3- and 1,2,4-substitutes. Also propyl,
Alkyl groups such as butyl are n-, i-, sec-, te
Including isomers such as rt-. Further, as the cyclopentadienyl complex, a compound in which zirconium is replaced with titanium, hafnium, vanadium, niobium, tantalum or chromium in the above compound in which M is zirconium is also exemplified.

Further, the cyclopentadienyl complex is
When used, they can be used alone or as a mixture. It may be used after being diluted with a hydrocarbon or a halogenated hydrocarbon. Further, in the present invention, as the cyclopentadienyl complex, a zirconocene compound having a central metal atom of zirconium and a group having at least two cyclopentadienyl skeletons as a ligand is preferably used.

The cyclopentadienyl complex catalyst used in the present invention is described in JP-A-4-253711,
Japanese Unexamined Patent Publication (Kokai) No. 4-279592 and Japanese Patent Publication No. 6-50358.
No. 5, JP-A No. 3-188092, or JP-A No.
The polymerization catalyst described in JP-A-84407 can also be used.

A cocatalyst may be used in combination with the cyclopentadienyl complex. Examples of the co-catalyst that can be used in this case include compounds that react with an ordinary aluminoxane compound or an ordinary metatheron compound to form a stable anion.

The above ethylene-α.olefin copolymer can be easily produced by a known method using the above cyclopentadienyl complex. Specifically, ethylene and α-olefin are In the presence of a cyclopentadienyl complex (or a catalyst system including the same; hereinafter, when referred to as a "catalyst system", these are collectively referred to), in a wide temperature and pressure range, liquid phase weight such as solution polymerization and slurry polymerization It can be produced by polymerizing by a legal method or a gas phase polymerization method. In particular, in order to polymerize the above mecyclopentadienyl complex in combination with the above aluminoxane compound, JP-A-61-130314 and JP-A-60-35 disclose.
No. 006, No. 60-35007, No. 58-1
No. 9309, No. 60-35008, and Japanese Patent Laid-Open No.
According to the method described in Japanese Patent Publication No. 163088, etc.,
In order to polymerize the cyclopentadienyl complex and a compound which reacts with the cyclopentadienyl complex to form a stable anion in combination, polymerization is described in European Patent 277,00.
Polymerization can be carried out according to the high-pressure ionic polymerization method described in the specification No. 4, International Publication WO92 / 01723, and the like.

In the molecular weight distribution of the ethylene-α-olefin copolymer, the ratio Mw / Mn of the weight average molecular weight to the number average molecular weight measured by GPC is preferably 4 or less, and 2 or less. Is more preferable. In addition, the MFR of the ethylene-α-olefin copolymer (JIS K-7
210; measured at 190 ° C. under a load of 2.16 kg) is preferably 0.01 to 300 g / 10 min, more preferably 0.1 to 150 g / 10 min, and particularly preferably 0.5 to 3 g.
0 g / 10 minutes.

Further, as the above-mentioned other polyolefin to be used together with the above-mentioned elastic polyolefin in the present invention, polyethylene, polypropylene, poly 1-butene and modified products thereof are preferably cited. In addition, the molecular weight of the other polyolefin is preferably 10,000 to 1,000,000.

The use ratio of the elastic polyolefin to the other polyolefin in the elastic composite fiber is
Above elastic polyolefin: Other above polyolefin =
It is preferably 40 to 90:60 to 10 (weight ratio).

The fiber length of the elastic composite fiber is 3 to.
It is preferably 76 mm, and the fineness is preferably 0.1 to 30 denier.

Next, the structure of the elastic composite fiber will be described with reference to the drawings. Here, FIGS. 3 to 14 are enlarged width direction cross-sectional views showing first to twelfth forms of the elastic composite fiber, respectively.

The elastic composite fiber 30 of the first embodiment shown in FIG.
Reference numeral 1 is a fiber having a core-sheath structure in which the elastic polyolefin is used as the core component 301a and the other polyolefin is used as the sheath component 301b. More specifically, the core component 301a and the sheath component 301b are both columnar, and the core component 301a is located substantially in the center of the sheath component 301b. In the elastic composite fiber 301, the cross-sectional area of the core component 301a and the sheath fiber 301b
It is preferable that the ratio with respect to the cross-sectional area of is 40 to 90:60 to 10. Such a fiber having a core-sheath structure can be produced by a generally known production method.

Second Embodiment Elastic Composite Fiber 30 shown in FIG.
2 is a fiber having a side-by-side structure.
More specifically, the elastic portion 302a made of the elastic polyolefin and the non-elastic portion 302b made of the other polyolefin each have a semicircular sectional shape. In the elastic composite fiber 302, the ratio of the cross-sectional area of the core component 302a to the cross-sectional area of the sheath fiber 302b is 1: 1. Such side-by-side structure fibers are
It can be produced in the same manner as a commonly known production method.

Third Embodiment Elastic Composite Fiber 30 shown in FIG.
3 is a modified example of the fiber having the core-sheath structure shown in FIG. 3, in which three core components 303a are arranged at substantially equal intervals in the center of the sheath component 303b.

The elastic composite fiber 30 of the fourth embodiment shown in FIG.
4 is a modification of the fiber having the core-sheath structure shown in FIG. 3, in which the substantially elliptical core component 304a is biased to the side of the sheath component 304b.

A fifth embodiment of elastic composite fiber 30 shown in FIG.
5 is a modification of the fiber having the side-by-side structure shown in FIG. 4, in which the substantially elliptical elastic portion 305a is
It is biased to the side of the inelastic portion 305b.

A sixth embodiment of elastic composite fiber 30 shown in FIG.
6 has a shape such that the area of the circle is divided into three by the elastic portion 306a, and as a result, three inelastic regions 306b are formed.

The elastic composite fiber 30 of the seventh embodiment shown in FIG.
7 is a modification of the fiber shown in FIG.
The area of the circle is divided into six by a, and as a result, six inelastic regions 307b are formed.

The elastic composite fiber 3 of the eighth embodiment shown in FIG.
Reference numeral 08 denotes a modification of the fiber shown in FIG. 8, which has a shape such that the area of the circle is divided into four by the wide elastic portion 308a, and as a result, four small inelastic regions 30 are formed.
8b are formed.

The elastic composite fiber 3 of the ninth embodiment shown in FIG.
09 has the elastic portion 309 a as a core, and the elastic portion 309 a
A fold-shaped inelastic portion 309b is provided around the periphery of a. In this embodiment, it is preferable that the non-elastic portion 309b is spirally provided around the elastic portion 309a with respect to the longitudinal direction of the fiber.

The elastic composite fiber 310 of the tenth embodiment shown in FIG. 12 is a modified example of the fiber shown in FIG. 11, and the elastic portion 3 has a triangular shape in which each side is curved toward the center side.
10a is formed, and a cylindrical inelastic portion 310b is arranged on each vertex of the elastic portion 110a. Also in this form, it is preferable that the non-elastic portion 310b is provided spirally around the elastic portion 310a in the longitudinal direction of the fiber.

The elastic composite fiber 311 of the eleventh embodiment shown in FIG. 13 is a so-called split fiber, and the elastic portion 311a and the non-elastic portion 311b each having a circular arc-shaped cross section.
, Are alternately arranged in the same number, and have a cylindrical shape as a whole.

The elastic composite fiber 312 of the twelfth embodiment shown in FIG. 14 is a so-called split fiber, and an elastic portion 312a and an inelastic portion 312b, each of which has a linear cross section,
They are arranged alternately and have a cylindrical shape as a whole.

The elastic conjugate fiber preferably has a permanent set of 60% or less, more preferably 50% or less and a hysteresis ratio of 6.0 or less, more preferably 5.0 or less. When the permanent set and the hysteresis ratio exceed the above range, the stretchability as an elastic fiber decreases, such as the crimpability of the fiber decreases.
Not preferred.

The permanent set and the hysteresis ratio were measured as follows. Permanent strain measurement method: 100% of the sample was measured in the same manner as the hysteresis ratio measurement method described below.
The length of the sample was measured when the distance between the chucks was set to the initial distance after stretching by 100%, and the length that cannot be relaxed with respect to the initial length (the distance between the initial chucks) when stretched 100% (stretched longer than the initial length The ratio (%) of the length (the length of the broken portion) was determined and this was taken as the permanent set. Measuring method of hysteresis ratio;
To examine the elasticity of each sample, the hysteresis ratio was measured using an elongation tester with an integrating device. JIS L1015
And fixing each sample to a testing machine based on L1096, and then stretching each sample 100% at a speed of 300 mm / min to create a stretching curve, and then loosening at the same speed to obtain the initial length between chucks. The relaxation was stopped at a certain place to create a relaxation curve, the areas under the stretching curve and the relaxation curve were measured, and these were substituted into the following equation to calculate the hysteresis ratio. Hysteresis ratio = Area under stretch curve / Area under relaxation curve

The nonwoven fabric may be composed of only the elastic composite fibers, but may contain other fibers together with the elastic composite fibers. In the non-woven fabric in the case of using the other fiber, the content of the elastic composite fiber is preferably 40% by weight or more. The other fibers used in this case include polyethylene, polypropylene, polyester, polyamide,
Common fibers such as acrylic, rayon, cotton, silk and pulp are used.

The nonwoven fabric has a permanent set of 60.
% Or less, more preferably 50% or less, and the hysteresis ratio is 6.0 or less, more preferably 5.0 or less. If the permanent set and the hysteresis ratio exceed the above ranges, the fit property may be deteriorated, which is not preferable. The permanent strain and the hysteresis ratio are
It can be measured in the same manner as the above-mentioned permanent set and hysteresis ratio of the elastic composite fiber.

In the pants-type disposable diaper of the present invention, even if the elastic side panel is composed of a sheet made of only the non-woven fabric, the effect of the present invention is sufficiently exhibited. As the above, the effect of the present invention can be sufficiently achieved even if a laminated sheet in which the above-mentioned nonwoven fabric is laminated with another stretchable material, for example, a thermoplastic elastomer film is used. The use of such a laminated sheet is preferable because the stretchable physical properties of the stretchable side panel can be freely controlled. As the laminated form of the thermoplastic elastomer film and the non-woven fabric, for example, a form of laminating the thermoplastic elastomer film on one side of the non-woven fabric, a form of laminating the thermoplastic elastomer film on both sides of the non-woven fabric, and the heat Examples include a mode in which the above nonwoven fabric is laminated on both sides of the plastic elastomer film. Examples of the material forming the thermoplastic elastomer film include urethane, styrene, ester, and olefin-based thermoplastic elastomers. Particularly, an ethylene-α-olefin copolymer produced using a metallocene catalyst is preferable. Used.

The pants-type disposable diaper of the present invention has been described above based on its preferred embodiment. However, the pants-type disposable diaper of the present invention is not limited to the above-mentioned embodiment, and other modifications are possible. For example, the stretchable side panel may be joined and fixed only to the left and right side edge portions of either the back side portion A or the abdominal side portion C. Also,
The stretchable side panel may be made of a sheet containing only the nonwoven fabric, which is bonded and fixed to any one of the back side portion and the abdominal side portion. Further, the stretchable side panel may be one in which a non-stretchable portion formed of a non-stretchable member and a stretchable portion formed of a sheet containing the nonwoven fabric are arranged in multiple rows and alternately. . Further, the joining and fixing of the stretchable side panels 20, 20 'is not limited to a position corresponding to the side of the wearer's body, and may be a position of the wearer's body on the ventral side or the back side.

[0065]

EXAMPLES The effectiveness of the pants-type disposable diaper of the present invention will be illustrated below with examples. However, the scope of the invention is not limited to such examples.

Manufacturing Example 1 Melt Index MI (M
FR) = 15 g / 10 min formed density ρ = 0.8
7 g / cm ³ of ethylene-1-octene copolymer (permanent strain 20%, hysteresis ratio 2.2) was used as the core component 301a.
Used as melt index MI = 15g / 10m
The high-density polyethylene having a density ρ = 0.95 g / cm ³ formed of in was used as the sheath component 301b to produce the elastic composite fiber 301 of the first embodiment shown in FIG. The ratio of the cross-sectional area of the core component 301a to the cross-sectional area of the sheath fiber 301b was 80:20, and the fineness was 2d × length 51 mm. The permanent set was 30% and the hysteresis ratio was 3.0. Then, the elastic composite fiber 100
%, And a card web having an embossing ratio of 10 area% and a surface temperature of 13% is produced.
Rolled at 8 ° C at 5m / min, basis weight 25g /
A m ² non-woven fabric was obtained. The resulting nonwoven fabric has a permanent set of 28.
%, The hysteresis ratio is 3.2, and the thickness is 0.7.
In mm, a smooth and good texture was obtained as in a normal polyethylene nonwoven fabric.

[Production Example 2] Melt index MI = 1
Density formed at 5 g / 10 min ρ = 0.87 g / cm
³ ethylene-1-octene copolymer (permanent set 20
%, A hysteresis ratio of 2.2) as the elastic component 305a, and a high density polyethylene having a density ρ = 0.95 g / cm ³ formed at a melt index MI = 15 g / 10 min as the inelastic component 305b. The elastic composite fiber 305 of the fifth embodiment shown was produced. In the obtained elastic conjugate fiber, the ratio of the sectional area of the elastic component 305a to the sectional area of the inelastic component 305b was 70:30. The fineness was 2d × length 51 mm, the permanent set was 35%, and the hysteresis ratio was 3.2. The obtained elastic composite fiber was treated in the same manner as in Production Example 1 to produce a nonwoven fabric having a basis weight of 35 g / m ² . The resulting nonwoven fabric has a permanent set of 21% and a hysteresis ratio of 2.
6, the thickness was 1.1 mm, the texture was excellent, and the elasticity was good.

[Examples 1 and 2] The nonwoven fabrics obtained in Production Examples 1 and 2 were used as stretchable side panels, and
The pants-type disposable diaper shown in was produced (Examples 1 and 2). About these pants-type disposable diapers, 1
A test on wearing comfort was performed on 0 monitors.
As a result, the pants-type disposable diapers of Examples 1 and 2 (invention) had low skin irritation, and had good feel to the touch, texture and wearing feeling.

[0069]

In the pants-type disposable diaper of the present invention, since the stretchable side panel is made of the sheet containing the above-mentioned nonwoven fabric, it has low skin irritation, is excellent in touch and feel, and has a comfortable wearing feeling. In addition, it has excellent fit around the waist and prevention of slipping off, and excellent leakproofness of excrement. Furthermore, it is easy to attach and detach diapers to infants etc. while sitting or standing. Can be done.

[Brief description of drawings]

FIG. 1 is a perspective view showing a preferred embodiment of a pants-type disposable diaper of the present invention.

FIG. 2 is a partially cutaway exploded view of the disposable diaper shown in FIG.

FIG. 3 is an enlarged width direction cross-sectional view showing a first form of elastic composite fiber.

FIG. 4 is an enlarged width direction cross-sectional view showing a second form of elastic composite fiber.

FIG. 5 is an enlarged width direction cross-sectional view showing a third form of elastic composite fiber.

FIG. 6 is an enlarged width direction sectional view showing a fourth mode of the elastic composite fiber.

FIG. 7 is an enlarged width direction sectional view showing a fifth mode of the elastic composite fiber.

FIG. 8 is an enlarged width direction sectional view showing a sixth mode of the elastic composite fiber.

FIG. 9 is an enlarged width direction sectional view showing a seventh mode of the elastic composite fiber.

FIG. 10 is an enlarged width direction sectional view showing an eighth mode of the elastic composite fiber.

FIG. 11 is an enlarged width direction sectional view showing a ninth mode of the elastic composite fiber.

FIG. 12 is an enlarged width direction sectional view showing a tenth form of elastic composite fiber.

FIG. 13 is an enlarged width direction sectional view showing an eleventh form of elastic composite fiber.

FIG. 14 is an enlarged width direction sectional view showing a twelfth form of elastic composite fiber.

[Explanation of Codes] 1 Pants-type disposable diaper 11 Top sheet 12 Back sheet 13 Absorber 14 Front waist portion 14 'Rear waist portion 15 Waist opening 17 Leg opening 20 Stretchable side panel 21 Girth elastic member 22 Leg Elastic member 23 waist elastic member 30 waste tape 31 seal portion A back portion B crotch portion C abdominal portion D near waist opening E waistline portion

Claims (1)

[Claims] 1. A main body having a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorber interposed between these sheets, and a pair of stretchable side panels. The stretchable side panels of are respectively disposed between the waist opening and the pair of leg openings, and the waist opening and the pair of leg openings include:
A pants-type disposable diaper having elastic members for forming gathers on its peripheral portions, wherein the elastic side panel includes elastic polyolefin and another polyolefin different from the elastic polyolefin. A pants-type disposable diaper comprising a sheet containing a non-woven fabric containing a composite fiber and having a permanent set of 60% or less and a hysteresis ratio of 6.0 or less.