JPH09313532A - Sanitary napkin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sanitary napkin which is less simulative for skin and can be easily formed. SOLUTION: This sanitary napkin has a liquid permeable upper surface sheet 2 to be in contact with skin, a liquid impermeable rear surface sheet 3 not to be in contact with skin, and a liquid retaining absorbent 4 between the upper surface sheet 2 and the rear surface sheet 3. And a pair of three- dimensional guards 10 are formed on the right/left sides of the upper surface sheet 2 in the longitudinal direction. The three-dimensional guards 10 have elastic members 11, which are made of an ethylene-α-olefin copolymer whose permanent strain is not highre than 50% and whose hysteresis ratio is not higher than 5.0.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a sanitary napkin having low skin irritation and good moldability.

[0002]

2. Description of the Related Art Conventionally, as a sanitary napkin, a liquid-permeable skin contact surface, a liquid-impermeable non-skin contact surface, and the skin contact surface and the non-skin contact surface have been used. It is widely used that it has a liquid-retaining absorption part interposed between the skin contact surface and a pair of left and right three-dimensional guards are arranged on both left and right sides in the longitudinal direction of the skin contact surface. There is. The three-dimensional guard is for preventing liquid leakage from the side edge portion, and usually the outer side of the napkin is fixed to the skin contact surface, and the inner side is a free end (Fig. 1). An elastic member made of ordinary rubber or the like is arranged at the free end of the elastic member to form a gather.

However, the sanitary napkin having such an elastic member made of ordinary rubber or the like has a problem such as irritation to the skin of the wearer. Further, the above-mentioned ordinary rubber has a problem that molding processability is poor and productivity is poor.

Therefore, an object of the present invention is to provide a sanitary napkin having low skin irritation and excellent moldability.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a sanitary napkin having a specific copolymer as an elastic member for a three-dimensional guard has the above-mentioned object. We have found that it can be achieved.

The present invention has been made on the basis of the above findings, and is a liquid-permeable skin contact surface, a liquid-impermeable non-skin contact surface,
And a liquid retaining absorbent portion interposed between the skin contact surface and the non-skin contact surface, and a pair of left and right three-dimensional guards are arranged on both left and right sides in the longitudinal direction of the skin contact surface. In the sanitary napkin, the three-dimensional guard includes an elastic member, and the elastic member has an ethylene-α having a permanent strain of 50% or less and a hysteresis ratio of 5.0 or less.
-Provides a sanitary napkin characterized by being formed of an olefin copolymer.

Further, the present invention provides the above sanitary napkin, wherein the ethylene-α-olefin copolymer has a density of 0.90 g / cm ³ or less. The present invention also provides the sanitary napkin, wherein the elastic member is formed of an ethylene-α-olefin copolymer obtained by copolymerization using a cyclopentadienyl complex as a catalyst. is there. Further, the present invention provides the above sanitary napkin, wherein the elastic member is formed of an ethylene-α-olefin copolymer obtained by copolymerization using a metallocene catalyst.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The sanitary napkin of the present invention will be described in more detail below. The sanitary napkin of the present invention is characterized in that the three-dimensional guard includes an elastic member formed of a specific copolymer.

The above specific copolymer used in the sanitary napkin of the present invention has a permanent set of 50% or less, preferably 0 to 30%, and a hysteresis ratio of 5.0 or less, preferably 1. 0-3.5 ethylene-α
-It is an olefin copolymer. When the permanent strain is 50% or less, the region in which the elastic member can be fixed can be widened, and when the hysteresis ratio is 5.0 or less, responsiveness is improved. On the other hand, when the permanent set exceeds 50% or the hysteresis ratio is 5.0.
If it exceeds, the fit of the gather portion formed by the elastic member to the body is deteriorated.

The permanent set and the hysteresis ratio are
Each is measured as follows. Measurement method of permanent strain: In the same manner as the measurement method of the hysteresis ratio described below, after elongating the sample by 100%, measure the length of the sample as the initial distance between chucks, and measure the initial length when elongating 100%. The ratio (%) of the non-relaxable length (length of the portion elongated and longer than the initial length) to the length (the initial distance between the chucks) was determined, and this was defined as the permanent strain. Hysteresis ratio measurement method; 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 using the elastic member, and the sample was placed on the tester with a distance between chucks of 100 m.
m and then each sample is 300 mm /
100% stretching at a speed of 10 min to form a stretching curve, and then loosening at the same speed to make the gap between the chucks equal to the initial length of 10%.
Relaxation was stopped at 0 mm to form a relaxation curve, the area under the stretching curve and the area under 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 where the hysteresis ratio of the true elastomer is 1.0
Therefore, when the hysteresis ratio of the sample is measured, a sheet, a film, or a filament having a hysteresis ratio of less than 5 is suitable as an elastic material for sanitary products such as sanitary napkins. The ethylene-α-olefin copolymer is not particularly limited as long as it satisfies the above-mentioned permanent set and the above-mentioned hysteresis ratio, but it is an ethylene-α-olefin copolymer obtained by copolymerization using a cyclopentadienyl complex as a catalyst. Polymers are preferred.

In the above ethylene-α-olefin copolymer, the α-olefin to be copolymerized with ethylene is an α-olefin having 3 to 30 carbon atoms, specifically, propylene, 1-butene, 1- Pentene, 1-hexene, 1-octene, 1-heptene, 4-methylpentene-1,4-methylhexene-1,4,4-dimethylpentene-1, octadecene and the like can be mentioned. Among these, 1-hexene, 1-octene, 1-heptene, 4
-Methyl-pentene-1 is preferably used.

Further, in the ethylene-α-olefin copolymer, the cyclopentadienyl complex used as a catalyst when copolymerizing ethylene and α-olefin is a compound represented by the following formula (I): Etc.

ML _X (I) [wherein M represents a transition metal selected from the group consisting of Zr, Ti, Hf, V, Nb, Ta and Cr, and L represents
A ligand having a cyclopentadienyl skeleton, which is a ligand coordinated to the transition metal, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryl group having 1 to 12 carbon atoms.
Roxy group, C1-C12 trialkylsilyl group, S
O 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 as the valence of the above transition metal. Is. However, when a plurality of Ls are coordinated, they may be different groups, but at least one is a group having a cyclopentadienyl skeleton. That is,
When x is 1, L is a group having a cyclopentadienyl skeleton, and when x is 2 or more, at least one of a plurality of L is a cyclopentadienyl skeleton. Is a group having ]

Examples of the group having a cyclopentadienyl skeleton include cyclopentadienyl group, methylcyclopentadienyl group, dimethylcyclopentadienyl group, trimethylcyclopentadienyl group and 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.

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

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 compounds in which M is zirconium are 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) methyl zirconium monochloride, ethylene bis (indenyl) zirconium bis (methane sulfonate), ethylene bis (indenyl) zirconium bis (p-toluene sulfonate), ethylene bis (indenyl) zirconium bis (trifluoromethane sulfonate), ethylene Bis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, isopropylidene (cyclopenta Enyl - fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl - methylcyclopentadienyl) zirconium dichloride, dimethylsilylene bis (cyclopentadienyl)
Zirconium dichloride, dimethylsilylene bis (methylcyclopentadienyl) Zirconium dichloride, dimethylsilylene bis (dimethylcyclopentadienyl)
Zirconium dichloride, dimethyl silylene bis (trimethylcyclopentadienyl) zirconium dichloride, dimethyl silylene bis (indenyl) zirconium dichloride, dimethyl silylene bis (indenyl) zirconium bis (trifluoromethane sulfonate), dimethyl silylene bis (4,5,6,6) 7-Tetrahydroindenyl) zirconium dichloride, dimethylsilylenebis (cyclopentadienyl-fluorenyl) zirconium dichloride, diphenylsilylenebis (indenyl)
Zirconium dichloride, methylphenylsilylene bis (indenyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, bis (cyclopentadienyl) methylzirconium monochloride, bis (cyclopentadiene) Dienyl) ethyl zirconium monochloride, bis (cyclopentadienyl) cyclohexyl zirconium monochloride, bis (cyclopentadienyl) phenyl zirconium monochloride, bis (cyclopentadienyl) benzyl zirconium monochloride, bis (cyclopentadienyl) ) Zirconium monochloride monohydride, bis (cyclopentadienyl) methyl zirconium monohydride, bis (cyclopentadienyl) Methylzirconium, bis (cyclopentadienyl) diphenylzirconium, bis (cyclopentadienyl) dibenzylzirconium, bis (cyclopentadienyl) zirconium methoxychloride, bis (cyclopentadienyl) zirconium ethoxy chloride, bis (cyclopentapenta Dienyl) zirconium bis (methanesulfonato), bis (cyclopentadienyl) zirconium bis (p-toluenesulfonato), bis (cyclopentadienyl) zirconium bis (trifluoromethanesulfonato), bis (methylcyclopentadiene) (Enyl) zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium ethoxy chloride, bis (dimethylcyclopente) Dienyl) zirconium bis (trifluoromethanesulfonato), bis (ethylcyclopentadienyl) zirconium dichloride, bis (methylethylcyclopentadienyl) zirconium dichloride, bis (propylcyclopentadienyl) zirconium dichloride, bis (methylpropylcyclo) Pentadienyl) zirconium dichloride, bis (butylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium bis (methanesulfonate), bis (trimethyl) Cyclopentadienyl) zirconium dichloride, bis (tetramethylcyclopentadienyl) zirconium dichloride, bis (pentamethylcyclopentadiene Enyl) 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, examples of the compound include a cyclopentadienyl complex in which zirconium is replaced with titanium, hafnium, vanadium, niobium, tantalum, or chromium in the above compound in which M is zirconium.

The above 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. Particularly, in the present invention, a zirconocene compound having a central metal atom of zirconium and a ligand having a group having at least two cyclopentadienyl skeletons is preferably used as the cyclopentadienyl complex.

Further, the cyclopentadienyl complex is
It can also be used in combination with a usual aluminoxane compound or a compound which reacts with the cyclopentadienyl complex to form a stable anion.

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.

The mixing ratio of ethylene and α-olefin in the ethylene-α-olefin copolymer is preferably 40 to 98% by weight of ethylene and 60 to 2% by weight of α-olefin.

The above ethylene-α-olefin copolymer is obtained by mixing ethylene and α-olefin in the presence of a cyclopentadiene complex in an amount of 100 to 3,000 kg / c.
m ² , preferably 300 to 2,000 kg / cm ² , 1
It can be produced by polymerizing by a high pressure ionic polymerization method at a temperature of 25 to 250 ° C., preferably 150 to 200 ° C. In particular, in order to polymerize the cyclopentadienyl complex and the aluminoxane compound in combination, the method described in JP-A-6-61 is disclosed.
No. 1-130314, No. 60-35006,
Stable anions according to the methods described in JP-A-58-19309, JP-A-60-35008, JP-A-3-163088, etc., and by reacting with the cyclopentadienyl complex and the cyclopentadienyl complex. In order to polymerize the compound forming the compound in combination, European Patent No. 277,004, International Publication WO92 / 0172
Polymerization can be carried out according to the high-pressure ionic polymerization method described in JP-A No. 3 (Kokai) No. 3 and the like.

In the molecular weight distribution of the ethylene-α-olefin copolymer, the ratio Mw / Mn of the weight average molecular weight and the number average molecular weight measured by GPC is preferably 4 or less, and 2 or less. Is more preferable. Also, the MFR of an 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.

[0030] The ethylene-.alpha. · olefin copolymer, its density is preferably at 0.90 g / cm ³ or less, and even more preferably 0.880~0.860g / 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.

The ethylene-α / olefin copolymer has a blocking strength (blocking strength at 40 ° C., 24 hours) of 30 in a 180 ° peel test.
g / 55 mm or less, preferably 15 g / 55 m
m or less, and most preferably 5 g / 55 mm or less. The lower limit of the blocking strength of the ethylene-α-olefin copolymer is not particularly limited, as the lower the lower the roll of the ethylene-α-olefin copolymer roll does not slip, the better. The blocking strength is 30 g / 55 mm
If it exceeds, when the sheet made of the ethylene-α-olefin copolymer is in a roll shape, it may be stuck between the overlapping sheets, and the sheet may not be able to be unwound. Is preferred.

The ethylene-α / olefin copolymer has an adhesive strength of 50 g / in a 180 ° peel test.
It is preferably at least 30 mm, and 100 g / 30 mm
More preferably, it is 150 to 600 g / 30.
mm is most preferred. The upper limit of the adhesive strength is not particularly limited, since it is preferable that the upper limit is large enough to cause the material constituting the diaper to be broken. Also,
If the adhesive strength is less than 50 g / 30 mm, the ethylene-α-olefin copolymer may be peeled off from the back sheet or the like during diaper assembly.
If it exceeds 0 g / 30 mm, the film of the ethylene-α-olefin copolymer may be plastically deformed.

That is, the blocking strength and the adhesive strength are physical properties required from the viewpoint of improving the productivity of diapers. The above-mentioned blocking strength and the above-mentioned adhesive strength are each measured as follows.

[Blocking Strength (Blocking Strength at 40 ° C. for 24 Hours)] First, a measurement sample is prepared as follows. The ethylene-α-olefin copolymer is formed into a sheet having a thickness of 50 μm, and the sheet is cut into a strip of 50 × 55 mm to obtain a sample sheet. Two obtained sample sheets were stacked to obtain a sheet laminate, and a 10 kg load (170 mm × 11 mm) was placed on the sheet laminate.
0 mm), and 40 ° C./8
Obtain a measurement sample stored at 0% environmental conditions for 24 hours. In addition, in the said sheet laminated body, when the said sheet is rolled up in a roll form, it is piled up so that the mutually contacting surfaces as a front surface and a back surface of a roll may contact. Then
Using the obtained measurement sample, a 180 ° peel test is performed according to a conventional method under the following conditions, and the obtained value is defined as blocking strength. -Measuring machine: tensile tester (Tensilon), product name "RTA-100" manufactured by Orientec Co., Ltd.-Distance between chucks: 100 mm-Pulling speed: 300 mm / min-Return speed: 300 mm / min

[Adhesive Strength] First, a measurement sample is obtained as follows. A hot melt (specifically, a styrene rubber hot melt adhesive) is applied to a 30 × 100 mm strip-shaped polyethylene terephthalate film (PET film) at a basis weight of 30 g / m ² , and a 30 × 100 mm film is formed on the PET film. 30mm HM coating and 30x70mm PE
A T film part is formed. A 30 × 100 mm sample sheet is superimposed thereon so that the periphery thereof overlaps the periphery of the PET film, and thereafter, the sample is pressed at a pressure of 5 kg / cm ² for 5 seconds to obtain a measurement sample. That is, in this measurement sample, both the PET film and the sample sheet have a 30 × 30 mm square portion at one end bonded through the HM coating portion, and the remaining 30 × 70 mm.
The portion of mm is a non-adhesion region. Next, using the obtained measurement sample under the following conditions, 180
° A peel test is performed, and the obtained value is defined as the adhesive strength. -Measuring machine: Tensilon tensile tester, manufactured by Orientec Co., Ltd., product name "RTA-100"-Distance between chucks: 100 mm-Pulling speed: 300 mm / min-Return speed: 300 mm / min-PET film and The measurement was performed by pulling the end of the non-adhesion region with the sample sheet and pulling it.

The ethylene-α-olefin copolymer has a blocking strength (40%) when rolled into a roll.
(Blocking strength after storage at 1 ° C. for one month) is preferably 200 g / 55 mm or less at 180 ° peel strength.
More preferably, it is 0 g / 55 mm or less. The lower limit of the above-mentioned blocking strength is not particularly limited, since the lower the better, the smaller the roll of the ethylene-α-olefin copolymer does not cause a roll deviation.
When the blocking strength exceeds 200 g / 55 mm, when the sheet made of the ethylene-α-olefin copolymer is formed into a roll, the sheet may be stuck between overlapping sheets, and the sheet may not be able to be unwound. Therefore, it is preferable to be within the above range. The blocking strength is measured as described below. That is, the ethylene-α-olefin copolymer was formed into a sheet having a thickness of 50 μm, and a roll obtained by winding the sheet 2000 m into a roll was heated at 40 ° C./80% in an environment of 4 ° C.
After storing for a week (28 days), remove the sheet
The sample was cut out in a state of being laminated, and a sample (55 × 100 mm) in a state of two laminated layers was obtained. The 180 ° peel strength of the obtained sample was measured using a Tensilon tensile tester (trade name “RTA-10” manufactured by Orientec Co., Ltd.).
0 "), and the blocking strength is obtained by measuring according to a conventional method (distance between chucks: 50 mm,
(Tensile speed: 300 mm / min). The measured value is 50
The length was calculated by averaging five points measured in mm length.

Further, the surface friction coefficient of the above ethylene-α.olefin copolymer is preferably 1.0 or less, more preferably 0.5 or less, and 0.3-
Most preferably, it is 0.05. In the present invention,
As described later, the ethylene-α-olefin copolymer can be used in various forms such as a sheet, a thread rubber, and a nonwoven fabric. When used as a sheet, at least one surface has a surface friction coefficient in the above range. Is preferably satisfied. When the surface friction coefficient exceeds 1.0, blocking tends to occur when the film is rolled.
It is preferable to be within the above range. To be used as an elastic member of a disposable diaper, the hot melt adhesiveness and the blocking of the roll formed by winding the film are in a preferable range, that is, the blocking strength and the adhesive strength are in the above range. However, from this point as well, it is preferable that the surface friction coefficient be within the above-mentioned range. In order to keep the surface friction coefficient within the above range, for example, the surface of the T-die chill roll can be appropriately adjusted by roughening the surface or embossing the surface.

For the surface friction coefficient, a friction feel tester (trade name "KES-SE") manufactured by Kato-Tech Co., Ltd. was used, and a friction element wound with SUS304 wire having a thickness of 0.5 mm was used. In any of the sheet, the rubber thread, and the non-woven fabric, the same measurement can be performed by a known method.

Further, as the above ethylene-α / olefin copolymer, it is also possible to use one obtained by copolymerization using a known metallocene catalyst.

The elastic member made of the ethylene-α / olefin copolymer can be used in the form of a foamed sheet, rubber thread and fiber aggregate, film or the like.
The foamed sheet, the rubber thread, and the fiber aggregate can be formed as follows. In order to make the above-mentioned foamed sheet, "Fundamentals of plastic processing" (Polymer Society of Japan, issued March 25, 1982) or "Technical overview of foamed plastics" (Information Development Co., Ltd.,
(Published July 30, 1989), the above ethylene-α / olefin copolymer is crosslinked by electron beam crosslinking, chemical crosslinking, etc. It can be performed by foaming by the method of. To make the above thread rubber, "polymer processing,
One Point Fibers "(Kyoritsu Shuppan Co., Ltd., issued October 15, 1992) and the above-mentioned" Fundamentals of Plastic Processing ". To make the above film,
It can be performed according to the known T-die method and inflation method, and the film processing method described in "Plastic Processing Basics". The fiber assembly can be prepared by using a known method such as spunbonding, meltblowing or flash spinning.

The ethylene-α / olefin copolymer used in the present invention can be used in combination with various lubricants and anti-blocking agents within a range that does not impair the desired effects of the present invention.

As the above-mentioned lubricant, the lubricant described in "Plastic lubricity and lubricants" (published by Nikkan Kogyo Shimbun, June 30, 1977) can be preferably used, and specifically, hydrocarbons can be used. Examples thereof include fatty acids, fatty alcohols, fatty alcohols, fatty acid amides, esters, partial esters, and complex lubricants.

Hydrocarbon lubricants include liquid paraffin, industrial white mineral oil, petrolactam, petroleum wax, synthetic paraffin, synthetic hard paraffin, synthetic isoparaffin petroleum hydrocarbon, odorless light hydrocarbon, microcrystalline wax, polyethylene wax. , Polypropylene wax,
3 (2-xenosyl) -1,2 epoxypropane, polyethylene oxide wax, chlorinated paraffin, petroleum hydrocarbon resin and the like. Examples of the fatty acid-based lubricant include higher fatty acids having 12 to 22 carbon atoms. Examples of the fatty alcohol-based lubricant include propylene glycol, glycerin, triethylene glycol, mono- and dipentaethyritol, and a straight-chain aliphatic saturated monohydric alcohol having 8 to 18 carbon atoms. As fatty acid amide-based lubricants,
Examples thereof include amides of saturated fatty acids, monounsaturated fatty acids and polyunsaturated fatty acids.
N-substituted amides such as N'-methylenebisamide and N, N'-ethylenebisamide are preferably used. Specifically, higher fatty acid amides having 12 to 22 carbon atoms, ethylenebisstearic acid amide, ethylenebisoleic acid amide, erucic acid amide, stearic acid amide, oleic acid amide, ricinoleic acid amide, linoleic acid amide, linoleic acid amide , Stearyl erucamide, oleyl palmitamide, lauric amide, palmitic amide, N-stearyl stearamide,
Examples include N-oleyl oleamide, N-stearyl oleamide, N-oleyl stearamide, N-stearyl erucamide, N-oleyl palmitamide, and the like.

As the ester type lubricant and the partial ester type lubricant, stearic acid ester of straight chain alcohol having 2 to 16 carbon atoms, ethanediol montanic acid ester,
Butyl ricinoleate, ethyl palmitate, stearyl palmitate, dibutyl sebacate, 2-ethylhexyl adipate, n-octyl adipate, dioctyl sebacate, butyl tartrate, triethyl citrate, poly (1,3-butanediol, adipic acid) ) Esters, tributyl acetyl citrate, isooctyl epoxy stearate, glycerin monoacetate, triglyceride waxes such as hydrogenated edible oils and fats, hydrogenated macaque oil and the like. In addition, as the above lubricant, in addition to these,
Silicones such as methylhydrodienepolysiloxane, dimethylpolysiloxane and methylphenylpolysiloxane, and rosins such as gum rosin, wood rosin, tall oil rosin, dark tall oil rosin, dark wood rosin, partially hydrogenated rosin, fully hydrogenated rosin, etc. It can also be used.

As the anti-blocking agent, those described in "Latest Technology of Functional Filler" (CMC Co., Ltd., issued January 26, 1990) are used. , Oxides (silica, alumina, iron oxide, titanium oxide, magnesia, etc.), metal powders (copper, silver, nickel, stainless steel, iron, aluminum, etc.), carbonates (calcium carbonate, magnesium carbonate,
Zinc carbonate), hydroxides (aluminum hydroxide, magnesium hydroxide, etc.), silicates (glass, kaolin,
Talc, mica, wollastonite, etc.), sulfates (calcium sulfate, barium sulfate, etc.), carbon (carbon black, graphite, etc.), titanates (potassium titanate, barium titanate, etc.), nitrides (aluminum nitride, Silicon nitride, etc.), carbide (silicon carbide, titanium carbide, etc.), sulfide (molybdenum sulfide, zinc sulfide, etc.),
Phosphates (calcium phosphate, iron phosphate, etc.), ferrites (barium ferrite, calcium ferrite, etc.), wood flour, starch, various organic pigments, polystyrene-based fillers, nylon-based fillers, acrylic-based fillers and the like are effectively used. These anti-blocking agents may be appropriately selected in consideration of resin processing suitability and anti-blocking function.

Next, one embodiment of the sanitary napkin of the present invention will be described in more detail with reference to the drawings. here,
FIG. 1 is a partially cutaway perspective view showing an embodiment of the sanitary napkin of the present invention.

The sanitary napkin 1 of this embodiment shown in FIG.
Liquid-permeable skin contacting surface 2, liquid-impermeable non-skin contacting surface 3, and liquid-retaining absorbing part 4 interposed between the skin contacting surface 2 and the non-skin contacting surface 3. And a pair of left and right three-dimensional guards 10 are arranged on both left and right sides in the longitudinal direction of the skin contact surface 2.

More specifically, the skin contact surface 2 is formed of a liquid-permeable top sheet, and the non-skin contact surface 3 is formed of a liquid-impermeable back sheet. The absorber 4 is formed of a liquid-retaining absorber. The sanitary napkin 1 is vertically long. Such a configuration is similar to that of a conventional sanitary napkin, and each member can be formed using a known material without particular limitation.

The three-dimensional guard 10 is provided with the elastic member 11, and the elastic member 11 has the permanent strain and the hysteresis ratio within the above range.
-It is formed of an olefin copolymer. More specifically, as shown in FIG. 1, the three-dimensional guard 10 is formed by arranging strip-shaped hydrophobic nonwoven fabrics on both left and right sides of the napkin. Further, in the hydrophobic nonwoven fabric, only the outer side of the napkin is fixed to the surface sheet (skin contacting surface 2) along the longitudinal direction of the napkin, whereby the inner side of the napkin is extended in the longitudinal direction of the napkin. It is folded back along to form the free end 12. Further, a rubber elastic member 11 formed of the ethylene-α-olefin copolymer is arranged in the free end 12, and thus a gather is formed. The elastic member 11 is fixed inside the free end with an adhesive. As the hydrophobic non-woven fabric, a conventionally known one can be used without any particular limitation.

Since the sanitary napkin of the present embodiment is constructed as described above, it has excellent fit properties, excellent leak prevention properties, and little skin irritation. Further, the ethylene-α-olefin copolymer is excellent in molding processability and excellent in productivity.

The sanitary napkin of the present invention is not limited to the form shown in FIG. 1 and can be variously modified without departing from the spirit of the present invention. For example, the elastic member does not have to be a rubber thread, and the hydrophobic nonwoven fabric itself may be formed as a fiber assembly from the ethylene-α-olefin copolymer. That is, in the present invention, the three-dimensional guard itself may be formed of the elastic member.

[0052]

EXAMPLES The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited thereto.

Example 1 An ethylene-α-olefin copolymer polymerized using a cyclopentadienyl complex (“Engage EG8200”, trade name, manufactured by Dow Chemical Co .; specifically, ethylene-1-octene copolymer). Polymer, M
FR = 5, density = 0.870 g / cm ³ , permanent set = 17
%, Hysteresis ratio = 2.0, blocking strength [24
Time] = 4 g / 55 mm, blocking strength [4 weeks]
= 30 g / 55 mm, adhesive strength = 150 g / 30 mm,
Using a rubber thread having a surface friction coefficient of 0.2) as an elastic member of the three-dimensional guard, the sanitary napkin shown in FIG. 1 was produced. In the obtained sanitary napkin, the three-dimensional guard showed good elasticity, and when the wearing test was conducted on 10 panelists, no skin irritation was found.
The results are shown in [Table 1].

Comparative Example 1 A sanitary napkin was produced in the same manner as in Example 1 except that polyurethane was used instead of the ethylene-α.olefin copolymer. The polyurethane had a permanent set of 14%, a hysteresis ratio of 2.5, and a blocking strength [24 hours] = 4 g / 55.
mm, blocking strength [4 weeks] = 80 g / 55 m
m, adhesive strength = 140 g / 30 mm, surface friction coefficient =
0.25. In the obtained sanitary napkin, the three-dimensional guard showed good elasticity, but in the wearing test conducted under the same conditions as in Example 1, the skin irritation was high. The results are shown in [Table 1].

[Comparative Example 2] Instead of the ethylene-α-olefin copolymer, an ordinary low-density polyethylene ("LLD
PE "permanent set 80%, hysteresis ratio 7.0, blocking strength [24 hours] = 3 g / 55 mm, blocking strength [4 weeks] = 20 g / 55 mm, adhesive strength = 30
A sanitary napkin was produced in the same manner as in Example 1 except that 0 g / 30 mm and a surface friction coefficient of 0.15) were used. The obtained sanitary napkin had no skin irritation, but no elasticity was imparted to the three-dimensional guard. That is,
The low density polyethylene did not exhibit elasticity. The results are shown in [Table 1].

[0056]

[Table 1]

[0057]

INDUSTRIAL APPLICABILITY The sanitary napkin of the present invention has low skin irritation and excellent moldability.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a sanitary napkin of the present invention.

[Explanation of symbols]

 1 Sanitary napkin 2 Skin contact surface 3 Non-skin contact surface 4 Absorber 10 Solid guard 11 Elastic member 12 Free end

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryohiko Gunji 2606 Akabane Kai, Akaga, Haga-gun, Tochigi Prefecture Kao Stock Company Research Institute (72) Haruo Sakahashi 2606 Akabane Kai-cho, Haga County, Tochigi Research Institute, Kao Stock Company

Claims (4)

[Claims] 1. A liquid-permeable skin-contacting surface, a liquid-impermeable non-skin-contacting surface, and a liquid-retaining absorbing portion interposed between the skin-contacting surface and the non-skin-contacting surface. In the sanitary napkin having a pair of left and right three-dimensional guards disposed on both left and right sides in the longitudinal direction of the skin contact surface, the three-dimensional guard includes an elastic member, and the elastic member is A sanitary napkin, which is formed of an ethylene-α-olefin copolymer having a permanent set of 50% or less and a hysteresis ratio of 5.0 or less. 2. The sanitary napkin according to claim 1, wherein the ethylene-α-olefin copolymer has a density of 0.90 g / cm ³ or less. 3. The ethylene-α obtained by copolymerizing the elastic member using a cyclopentadienyl complex as a catalyst.
-The sanitary napkin according to claim 1, which is formed of an olefin copolymer. 4. The sanitary napkin according to claim 1, wherein the elastic member is formed of an ethylene-α-olefin copolymer obtained by copolymerization using a metallocene catalyst.