JP3155351B2 - Porous sheet and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous sheet having moisture permeability and waterproofness and a method for producing the same.
More specifically, the present invention relates to a porous sheet having excellent sheet strength and sealing properties, and having moisture permeability, water pressure resistance, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art
As a method for producing a porous sheet, there is known a method in which 40% by weight or more of an inorganic filler is mixed in an olefin resin such as polyethylene or polypropylene, and the mixture is formed into a sheet and then stretched uniaxially or biaxially. The porous sheet obtained in this manner is excellent in air permeability and moisture permeability and does not cause a dew condensation phenomenon, so that it is suitably used as a wallpaper or a sheet for packaging. Further, by imparting further flexibility to the excellent properties of such a porous sheet, for example, used for the back material of disposable diapers, etc., to impart flexibility to the porous sheet, as an olefin resin It has been proposed to use linear low-density polyethylene.

However, when a large amount of filler is mixed with low-density polyethylene, formed into a sheet, and then uniaxially stretched, the resulting stretched sheet suffers from anisotropy in physical properties, in particular, tearing in the longitudinal (stretching) direction. There was a problem that the strength was reduced. Further, when biaxially stretched, there is a problem in stretchability (uniform whitening property) and surface strength for uniformly performing an interfacial peeling phenomenon between the filler and the resin matrix. Particularly, both the uniaxially stretched sheet and the biaxially stretched sheet have a disadvantage that the heat sealability (adhesiveness and adhesive strength) suitable for subsequent processing is reduced.

For example, the above-mentioned porous sheet is bonded by a hot-melt adhesive during processing, but the adherend in this case is limited, and sufficient adhesive strength cannot be obtained. Applications are limited because of the need for adhesives,
There is a disadvantage that the cost increases. Further, in a portion where the body pressure changes drastically (for example, a crotch portion when used as a surface material or a back surface material of the absorbent article), a hole becomes large and a water pressure is reduced, or a stop attached via an adhesive is used. There are drawbacks such as the adhesive tape easily peeling off. As described above, the conventional porous sheet can satisfy all the required physical properties such as formability or flexibility, tensile / tear strength, heat sealability (adhesion and adhesive strength), moisture permeability, and water pressure resistance. Can not. Accordingly, an object of the present invention is to provide a porous sheet having excellent sheet strength and sealing properties, and having moisture permeability, water pressure resistance, and the like, and a method for producing the same. The object of the present invention is also to vaporize and release absorbed body fluid without leaking,
An object of the present invention is to provide an absorbent article which does not cause stuffiness and gives a comfortable wearing feeling.

[0005]

Means for Solving the Problems The inventors of the present invention have developed a suitable porous material having improved heat sealability and tensile strength, particularly from a composition of a polyolefin resin, a filler and a softening agent according to the method described above. As a result of various studies for the purpose of obtaining a porous sheet with good moldability, a porous sheet having extremely excellent functions was able to be obtained. That is, the present invention is a poly
100 parts by weight of olefin resin, 50-400 weight of filler
Composition comprising 0.1 part by weight and 0.1 to 20 parts by weight of a softening agent
(A) A sheet of polyolefin resin 100 weight
Parts by weight, filler 0-40 parts by weight and softener 0-10 parts by weight
Parts of the composition (b) consisting of
A porous sheet that has been subjected to a stretching process.
Therefore, the moisture-permeable sheet formed of the composition (a) is simply
A layer sheet area, the moisture-permeable sheet and the composition (b)
Non-pervious or low-pervious sheet formed is multilayered
The object has been achieved by providing a porous sheet having a multilayer sheet area alternately and in multiple rows .

[0006] Also provided is a method for producing a porous sheet according to the present invention, the composition and (a), by co-extrusion and the composition (b), the composition of the above composition (a) (B) forming a sheet-like material partially laminated, and stretching the formed sheet;
And a method of using the porous sheet as a backing material.
By providing an absorbent article characterized by the above,
The goal has been achieved .

Hereinafter, the porous sheet according to the present invention and the method for producing the same will be described in detail. The porous sheet according to the present invention is composed of a moisture-permeable sheet and a moisture-impermeable or low moisture-permeable sheet, and the polyolefin-based resin of the compositions (a) and (b) mainly used for these sheets includes ethylene, propylene and the like. The olefin homopolymer or copolymer is used without any particular limitation, among which high-density polyethylene,
Medium- and low-density polyethylenes, which are called medium-density polyethylene and linear low-density polyethylene, are preferred.
MFR is 0.1 to 10 g at 910 to 0.940 g / cm ³
A linear low-density polyethylene of / 10 minutes, preferably 0.1 to 5 g / 10 minutes is preferably used. It is also preferable to mix two or more of the above-mentioned polymers or copolymers of the present invention. Particularly, the crystalline polyolefin resin has a crystallinity of 5 to 25% by X-ray and a density of 0.86 to 0.9.
When a mixed resin obtained by blending a copolymer of ethylene and another α-olefin of 0 g / cm ³ (hereinafter also referred to as a soft resin) is used, the resulting porous sheet has moisture permeability. Since flexibility is imparted without loss, it is particularly excellent in tensile and tear strength. The soft resin is generally used in an amount of 20 to 100 parts by weight of the crystalline polyolefin resin.
It is blended at a ratio of １００100 parts by weight. It should be noted that a resin other than the polyolefin may be blended as long as the properties of the polyolefin resin are not lost.

[0008] The filler used in the present invention is not limited.
Fillers usually mixed in rubber or plastics, such as calcium carbonate, gypsum, calcium sulfate, calcium phosphate, magnesium carbonate, magnesium sulfate, hydrated silicic acid, silicic anhydride, soda ash, sodium chloride, sodium sulfate , Barium sulfate, talc, clay, various cements, volcanic ash, shirasu, titanium oxide, iron oxide, carbon black, various metal powders, and other inorganic substances or organic metal salts mainly composed of inorganic substances. In addition, thermosetting resins such as phenolic resins, epoxy resins, and sodium polyacrylate, resins obtained by crosslinking thermoplastic resins such as polyethylene, polypropylene, and polyacrylic ester with radiation and the like, resins higher than the above-mentioned molding (sheeting) temperature, etc. Organic substances. These fillers are 50 μm or less, preferably in the range of 0.05 to 30 μm, especially 0.1 to 5 μm
It is desirable to use it as a powder having a mean particle diameter of the order. If a filler with too large an average particle size is used,
When the denseness of the pores of the obtained stretched sheet is reduced and a filler having an average particle size that is too small is used, unevenness in stretching tends to occur and a good porous sheet cannot be obtained.

The compounding amount of the filler in the composition (a) is as follows:
50 to 40 with respect to 100 parts by weight of polyolefin resin
0 parts by weight, preferably 60 to 300 parts by weight;
When the amount is less than part by weight, the number of communication holes in the moisture-permeable region of the obtained porous sheet is reduced, so that the moisture permeability is reduced. When the amount is more than 400 parts by weight, it becomes difficult to form and stretch the sheet. The compounding amount of the filler in the composition (b) is 0 to 40 parts by weight, preferably 0 to 20 parts by weight, based on 100 parts by weight of the polyolefin resin.
In the case of 0 parts by weight, the non-permeability or low-permeability of the porous sheet is obtained in a completely non-permeable region or close thereto.
If the amount exceeds 40 parts by weight, the film strength and the heat sealability are reduced.

[0010] The softening agent used in the present invention is not particularly limited, but a plasticizer or a lubricant usually mixed in rubber or plastic, for example, a monoester composed of a fatty acid and an aliphatic alcohol, an aromatic carboxylic acid and an aliphatic carboxylic acid. Monoesters or polyesters composed of alcohols, polyesters composed of aliphatic polycarboxylic acids and polyalcohols, polyesters composed of monocarboxylic acids and / or polycarboxylic acids and monoalcohols and / or polyalcohols, and alcohols and / or carboxylic acids. Ester or polyester, aliphatic amide,
Aromatic amide, fatty acid metal soap, aromatic carboxylic acid metal soap, polybutadiene oligomer, polybutene oligomer, isobutylene oligomer, isoprene oligomer, petroleum resin, cumarone resin, ketone resin, chlorinated parifin, silicone oil, liquid paraffin, polyethylene wax And so on.

The amount of the softening agent in the composition (a) is 0.1 to 100 parts by weight of the polyolefin resin.
It is preferable to add 20 parts by weight, particularly 0.5 to 10 parts by weight. The amount is determined by the affinity of the softener with the polyolefin, the affinity with the filler and the flexibility required for the porous sheet, but if less than 0.1 part by weight, there is substantially no softening effect. If it exceeds 20 parts by weight, it bleeds out to the sheet surface, causing stickiness and poor adhesion. The blending amount of the softening agent in the composition (b) is 0 to 10 parts by weight based on 100 parts by weight of the polyolefin resin.
Particularly, it is preferable to add 0 to 7 parts by weight. The blending amount is determined by the affinity of the softening agent with the polyolefin, the affinity with the filler, and the flexibility required for the porous sheet. However, if it exceeds 10 parts by weight, it bleeds out to the sheet surface and becomes sticky and adheres. It becomes bad.

The method for producing the porous sheet according to the present invention includes the following method in addition to forming the composition (b) in a multilayer shape on a part of the sheet material of the composition (a) and stretching the composition. is there. For example, a sheet made of the composition (a) or the like formed by applying a non-moisture permeable sheet layer by an emulsion or solution coating method to a moisture-permeable sheet obtained by stretching a sheet made of the composition (a) or the like Is formed by appropriately laminating a stretched non-permeable sheet to a stretched moisture-permeable sheet. The method of multilayering a moisture-impermeable sheet on the sheet before stretching or the method of multilayering on the moisture-permeable sheet after stretching may be the above-described method of applying an emulsion or a solution or a laminating method. In the present invention, a method of stretching the composition (b) on a part of a sheet-like material of the composition (a) in a multi-layered form may be used. With such a structure, molding and stretching of the sheet can be achieved very easily. In addition, the resulting porous sheet retains moisture permeability and water pressure resistance, and is particularly excellent in tensile strength, heat sealability, and adhesive strength of the seal portion.

The area and shape of the moisture-permeable region formed only from the composition (a) of the porous sheet and the high-strength region formed of the composition (b) in a multilayer shape are not particularly limited. Also, from the viewpoint of moisture permeability and strength, the composition (a)
The area of the moisture-permeable region alone is preferably 20 to 95% of the entire sheet, and particularly preferably 40 to 80%. Further, from the viewpoint of strength, it is preferable that the end portion of the sheet is a constituent area where the composition (b) is laminated. The surface area ratio of the former and the latter is
It is not necessary to be constant in the forming direction, but rather it is preferable to repeatedly change (or increase or decrease) in the direction perpendicular to the forming direction according to the shape and required characteristics of the final product using the sheet. Such a shape is used in a usual co-extrusion molding technique. That is, it can be easily obtained by adjusting both resin flow paths of the die, the shape of the merging portion, the melt flow characteristics (a) and (b), and the supply speed to the die.

The moisture permeability of the moisture-permeable sheet comprising the composition (a)
The degree is 0.4-6g / 100cm^Two・ Hr, particularly preferably
0.8-4g / 100cm^Two・ Hr. Also the composition
(A) a non-woven sheet comprising the composition (b);
Non-breathable or multi-layered breathable or low-breathable sheet
The moisture permeability of the low moisture permeability region is 0 to 0.3 g / 100 cm.^Two・ H
r, particularly preferably 0.01 to 0.2 g / 100 cm^Two・ H
r. The moisture permeability of the single layer sheet part of the moisture permeable sheet
0.4g / 100cm^Two・ If it is lower than Hr, it will be effective in preventing
Poor fruit, and conversely, its moisture permeability is 6g / 100cm^Two・ Hr
When it exceeds, the water pressure resistance decreases, and the leakproofness decreases. multilayer
Moisture permeability in the sheet part is 0.3g / 100cm ^Two・ Hr
The adhesive strength and tensile strength decrease,
Also, the strength of the metal decreases.

According to the porous sheet thus constituted, a single-layer sheet area composed of the composition (a) and the composition (a)
And the multilayer sheet region composed of the composition (b) is alternately present in multiple rows, so that the single-layer sheet region composed of the composition (a) exhibits moisture permeability while maintaining waterproofness (water pressure resistance). Adhesiveness (heat sealability, hot melt adhesiveness) and tensile strength are shared in the multilayer sheet area composed of the product (a) and the composition (b). Overall, moisture permeability, water pressure resistance, heat sealability, adhesion A sheet having excellent properties and tensile strength is obtained, and is suitable for a back surface material of an absorbent article such as a sanitary napkin, a disposable diaper, and a wound covering material described below.

FIG. 1 is a perspective view showing one embodiment of an absorbent article using the porous sheet according to the present invention as a back material, and showing the absorbent article with a part cut away. FIG.
(A) is a plan view of a back material used for the absorbent article,
(B) is a sectional view taken along line ee in FIG. (A), and (c) is a sectional view taken along line ff in FIG. FIG. 3 shows one embodiment of a method for producing a porous sheet according to the present invention, and FIG. 3 (a) is a cross-sectional view of a sheet before stretching by an inflation method.
(B) is a sectional view of the incision sheet of (a).

FIG. 1 shows a sanitary napkin 1 which is one of the absorbent articles. The sanitary napkin 1 has a liquid-permeable surface material 2, a leak-proof back material 4, And an absorber 3 disposed between these two side materials. As shown in FIG. 2, the back material 4 of the sanitary napkin 1 (approximately 50 to 150 mm wide) has a non-permeable area 4B and a permeable area 4B.
A. The above-mentioned porous sheet comprising A is used, and in the application, the positional configuration of the permeable area of the porous sheet is as follows: non-permeable area 4B-permeable area 4A-non-permeable area 4B-permeable Area 4A-non-permeable area 4B, non-permeable area 4B-transparent area 4A
-The configuration of the non-permeable area 4B is preferable, and the ratio of the non-permeable area 4B at both ends in the length direction of the napkin is 95 to 7
It is particularly preferred that 0% and 5-30% occupy the center.

In addition, disposable diapers (about 200-
In the case of (600 mm width), the number of repetitions of the non-transmissive area 4B, the transmissive area 4A, the non-transmissive area 4B,... .
In the case of a diaper, it is preferable that the ratio of the non-transmissive area 4B at the front end to which the fastening tape is in contact is almost 100%. The absorbent article configured in this manner does not leak the absorbed body fluid, and easily vaporizes and releases the fluid,
Gives a comfortable fit without stuffiness.

In the method for producing a porous sheet according to the present invention, the composition is generally prepared by mixing the olefin resin, the filler, and the softening agent using high-speed stirring (mixing) such as a Henschel mixer. More preferably, the mixture is melt-kneaded by a twin-screw extruder or the like and formed into a pellet. In such preparations, small amounts of stabilizers, colorants,
Alternatively, the lubricant can be mixed simultaneously or separately.

The method for producing a sheet-like material in which the composition (a) / composition (b) is partially formed into a multilayer is not particularly limited, but coextrusion molding using two or more extruders is preferred. In the case of co-extrusion, the moisture permeable area 4A-the moisture-impermeable area 4B
-Moisture permeable area 4A-Even if the number of repetitions is large, it is easily determined by the die production, and the area ratio in the molding direction is also changed sequentially or repeatedly in the die structure and the discharge of the extruder. Since the two compositions are supplied from two extruders, no additional burden is imposed on the production.

There are two methods for forming a co-extruded sheet: an inflation method (circular die method) and a T-die method (flat die method), and the sheet forming before stretching of the present invention can be easily used in both methods. The molding temperature is 20 to 90 ° C. of the melting point of the polyolefin resin in the inflation method.
High temperatures are preferred, and in the case of the T-die method, an additional 20 to 50
C. higher temperatures are preferred. FIG. 3 shows a multilayer sheet according to the present invention manufactured by the inflation method.

As a roll stretching method for a sheet-like material, uniaxial stretching, or after uniaxial stretching, successively biaxially stretching in the horizontal direction by a tenter stretching machine, an air inflation stretching machine, a mandrel stretching machine, or the like, or simultaneously, in the longitudinal and longitudinal directions, A method of stretching in the transverse direction is employed. The stretching temperature is generally from room temperature to the melting point of the polyolefin resin, preferably a temperature 10 ° C. lower than the melting point. The stretching ratio is at least 1.2 times or more and 4 times or less in the uniaxial direction, that is, in the case of uniaxial stretching, in the longitudinal (MD) direction, and in the case of biaxial stretching, in the longitudinal (MD), transverse (TD) directions. The ratio is preferably 1.2 times or more and 4 times or less, respectively, in order to maintain excellent mechanical balance and strength and simultaneously exhibit excellent moisture permeability and water pressure resistance. More generally, it is preferable that after the stretching step, a heat treatment is performed under tension, and then cooled to room temperature below the stretching temperature and taken out. Further, in order to improve the printability and the adhesive strength of the sheet, a surface treatment such as a corona discharge treatment may be performed.

According to such a production method, the composition (b) can be easily polymerized at a desired position of the composition (a) by coextrusion molding or the like. Since the region composed only of the composition (a) can be the moisture-permeable region 4A, and the region composed of the composition (a) and the composition (b) can be the non-permeable region 4B.
It is possible to easily provide a moisture-permeable region at a desired position of the porous sheet, and it is possible to easily impart heat sealing strength to a necessary portion.

[0024]

【Example】

Preparation of composition: 100 parts by weight of linear low-density polyethylene (Ultzex 2520F, Mitsui Petrochemical Industries, Ltd.) and 150 parts by weight of surface-treated calcium carbonate (average particle size 1.1 μm) were blended with composition (a). , And polyester (trimethylolpropane / adipic acid / stearic acid = 2
SV consisting of mol / 1 mol / 4 mol = 240, AV =
1, OHV = 8) 5 parts by weight Composition of composition (b) was 100 parts by weight of linear low-density polyethylene (same as for composition (a)), titanium oxide (Ishihara Sangyo Co., Ltd., R-550, average) Particle size 0.2 μm) 3 parts by weight,
And 0.3 parts by weight of polyester (same as for composition (a)) Each of the above compositions was mixed with a 100 liter Henschel mixer, and then kneaded into pellets with a twin screw extruder having a diameter of 45 mm.

Sheet forming: A single-screw extruder having a diameter of 32 mm (hereinafter referred to as a extruder) as an extruder for the composition (a) and a single-screw extruder having a diameter of 25 mm (hereinafter referred to as an extruder) for the composition (b) ,
b), using a co-extrusion circular die known per se under the following molding conditions under a sheet width 30 after incision.
A 0 mm partial multilayer sheet was formed (the same pattern as in FIG. 3). Die diameter φ60mm, Die lip clearance = 1mm Cylinder a-temperature (° C) Die temperature (° C) Pick-up speed a Extruder 160-170-175 180 10m / min b Extruder 160-170-175

Stretching: Using a roll stretching machine with a diameter of 200 mm and a width of 300 mm, connected to the above-mentioned sheet molding machine, and having a thickness of 6 mm.
The 0 μm sheet was stretched 2.3 times at 80 ° C. The sheet pattern after stretching is the same as that of FIG. 2 (a). In FIG. 2 (b), 4B has a width of 50 mm, a length of about 40 mm and a thickness of about 8 μm.
(C) part width 10mm, length 100mm, thickness about 10μm,
The length from the ee part to the ff part was 90 mm. Also,
The thickness of the sheet was about 40 μm.

Comparative Example Using a pellet of the composition (a) of the above example, a sheet having a thickness of 60 μm was formed at the same temperature and take-up speed by the usual inflation film forming machine under the same conditions as in the example. Stretched. The obtained sheet thickness was about 40 μm (FIG. 4).

(Evaluation criteria) (1) Moisture permeability: Measured according to JIS ZO208 (2) Water pressure resistance: Measured according to JIS L1092B method (3) Tensile strength and elongation: Measured according to JIS P8113 (4) Heat sealability: The porous sheet is made of polyethylene-
A nonwoven fabric having a basis weight of 20 g / m ² made of a polypropylene composite fiber is overlaid, and the end of the nonwoven fabric is heated using a one-sided heating bar sealer (seal bar 10 × 30 mm) manufactured by Tester Sangyo Co., Ltd. at a pressure of 2 kg / cm ² and a time of 0 hours. .5 sec, temperature 130 ° C
Was heat sealed. The adhesive strength after heat sealing, the presence or absence of heat shrinkage, and the presence or absence of pinholes were measured, and the heat sealability was determined according to the following criteria.・ Samples with good quality ・ ・ ・ ○ ・ Samples with slight heat shrinkage ・ ・ ・ ・ ・ ・ ・ Samples with low adhesive strength and large heat shrinkage ×

(5) Tape adhesion: 20 on the porous sheet
Apply a hot melt adhesive with a thickness of μm (20 mm width x 1
50 mm in length), and this was superimposed on a cotton gold cloth and reciprocated once with a 5 kg roller to obtain a test sample. In this sample, the transfer of the pressure-sensitive adhesive to the cotton fabric when the cotton fabric was peeled from the porous sheet was determined according to the following criteria, and the tape adhesiveness of the sheet was determined.・ No migration of adhesive is observed at all ・ ・ ・ ○ ・ Partial migration of adhesive is observed ・ ・ ・ ・ ・ ・ ・ ・ Most of the adhesive migrates ・ ・ ・ ・ ・ ・... ×

[0030] (6) stuffiness index: polyethylene as a table surface material - polypropylene basis weight 20 g / m ² of non-woven fabric made of composite fibers, cotton-like pulp consisting of basis weight 260 g / m ² as an absorber, porous as backsheet A sanitary napkin is constructed using the sheet as shown in FIG. This sample was worn by 10 monitors, and the degree of stuffiness was evaluated according to the following criteria.・ Refreshing feeling without any stuffiness ・ ・ ・ ・ ○ ・ Some stuffiness ・ ・ ・ ・ ・ ・ ・ Very stuffy ・ ・ ・ ・ ・ ・ ・ ・ ・... ×× Physical properties of the porous sheet obtained according to the above criteria are collectively shown in [Table 1].

[0031]

[Table 1]

Further, when a sanitary napkin was manufactured using the porous sheets of the above Examples and Comparative Examples with the structure shown in FIG. 1, a conventional backing material (low-density polyethylene laminated paper) was obtained.
Compared with Comparative Example, the back material of the comparative example was excellent in heat sealability, hot melt adhesiveness, tape adhesiveness, and sheet strength, and had a comfortable mounting property.

[0033]

The porous sheet of the present invention has excellent sheet strength and sealing properties, and has moisture permeability, water pressure resistance and the like. In addition, an absorbent article using such a porous sheet as a back material vaporizes and releases the absorbed body fluid without leaking, and provides a comfortable fit without stuffiness.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of an absorbent section using a porous sheet according to the present invention, and showing a partially cut-away portion of the absorbent article.

FIG. 2 (a) is a plan view of a backing material used for an absorbent article, and thick arrows on the left side of the drawing show sheet forming and stretching directions. 2B is a cross-sectional view (width direction) of the back material of FIG. 2A along the line ee (width direction), and FIG. 2C is a cross-sectional view along the line ff of FIG.

3 shows an embodiment of a method for producing a porous sheet according to the present invention, FIG. 3 (a) is a sectional view of a sheet before stretching by an inflation method, and FIG. 3 (b) is a sectional view of a cut sheet of FIG. 3 (a). It is.

FIG. 4 shows a comparative example, in which FIG. 4 (a) is a plan view showing a (single-layer) porous region made of the composition (a), and FIG. 4 (b) is II- in FIG. 4 (a). FIG. 2 is a cross-sectional view (width direction) along the line II.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Absorbent article 2 Surface material 3 Absorber 4 Back material 4A Moisture permeable area composed of composition (a) 4B Non-permeable area 4A composed of composition (b) 4A 'Sheet area composed of composition (a) 4B' composition Sheet area consisting of object (b)

Continuation of the front page (51) Int.Cl. ⁷ Identification symbol FIB32B 27/32 (56) References JP-A-62-249739 (JP, A) Japanese Utility Model 1983-96937 (JP, U) Japanese Utility Model 1988 -81999 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00 A61F 13/15-13/84

Claims (3)

(57) [Claims] 1. A sheet of a composition (a) comprising 100 parts by weight of a polyolefin-based resin, 50 to 400 parts by weight of a filler and 0.1 to 20 parts by weight of a softening agent, 100 parts by weight of a polyolefin-based resin, A porous sheet obtained by partially laminating and stretching a sheet-like material of the composition (b) comprising 0 to 40 parts by weight of a filler and 0 to 10 parts by weight of a softening agent. Ru is formed by the object (a)
And the single layer sheet area of the moisture vapor permeable sheet in the moisture vapor permeable sheet and the composition (b) non-breathable that are formed in or low moisture permeability sheets and multi-rows alternating with multilayer sheet gamut a multilayer multi porous sheet, characterized in that it has. 2. A method for producing a porous sheet according to claim 1 wherein said composition and (a), by co-extrusion and the composition (b), the composition of the above composition (a) A method for producing a porous sheet, comprising: forming a sheet-like material obtained by partially laminating the material (b); and stretching the formed sheet. 3. An absorbent article comprising a liquid-permeable surface material, a leak-proof backing material, and an absorber disposed between the two surface materials, wherein the porous sheet according to claim 1 is provided with the porous sheet. An absorbent article characterized by being used as a backing material.