JPH06910A - Porous sheet and manufacture thereof - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a porous sheet having excellent sheet strength and sealability, and having moisture permeability, water pressure resistance and the like, and a method for producing the same, and vaporizing and releasing absorbed body fluid without leaking, To provide an absorbent article that gives a comfortable wearing feeling without stuffiness. A porous sheet according to the present invention comprises a moisture-permeable sheet and a non-moisture-permeable or low-moisture-permeable sheet partially laminated on the moisture-permeable sheet. The moisture permeable sheet portion and the non-moisture permeable or low moisture permeable sheet portion have a multi-layered non-moisture permeable or low moisture permeable region alternately and in multiple rows.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
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, formed into a sheet, and then stretched in a uniaxial or biaxial direction. The porous sheet thus obtained is excellent in air permeability and moisture permeability and does not cause a dew condensation phenomenon, and thus is suitably used as a wallpaper, a sheet for packaging or the like. Further, by further imparting flexibility to the excellent properties of such a porous sheet, for example, it is used as a backing material for disposable diapers, and in order to impart flexibility to the porous sheet, an olefin resin is used. It has been proposed to use linear low density polyethylene.

However, when a large amount of a filler is mixed with low-density polyethylene and formed into a sheet and then uniaxially stretched, the resulting stretched sheet has a decrease in anisotropic physical properties, particularly tearing in the longitudinal (stretching) direction. There was a problem of reduced strength. Further, when biaxially stretched, there are problems in stretchability (uniform whitening property) and surface strength that allow the interfacial peeling phenomenon between the filler and the resin matrix to be performed uniformly. In particular, the uniaxially stretched and biaxially stretched sheets both have a drawback that the heat sealability (adhesiveness and adhesive strength) suitable for subsequent processing is lowered.

For example, the above-mentioned porous sheet is adhered by a hot-melt adhesive during its processing, but the adherend in that case is limited, and sufficient adhesive strength cannot be obtained. The application is limited in that it requires an adhesive,
There is a drawback that the cost is high. Further, in a portion where body pressure changes drastically (for example, a crotch portion when used as a surface material or a back surface material of an absorbent article), the water pressure is reduced due to an increase in pore size, or a stopper attached via an adhesive is used. There are drawbacks such as easy removal of the adhesive tape. As described above, the conventional porous sheet can satisfy all the desired physical properties such as moldability or flexibility, tensile / tear strength, heat sealability (adhesiveness and adhesive strength) moisture permeability, and water pressure resistance. Can not. Therefore, 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 the absorbed body fluid without leaking,
An object of the present invention is to provide an absorbent article that does not get stuffy and gives a comfortable wearing feeling.

[0005]

Means for Solving the Problems The inventors of the present invention have found that the composition of a polyolefin resin, a filler, and a softening agent according to the method as described above can be applied to a suitable porous material having particularly improved heat sealability and tensile strength. As a result of various studies aimed at obtaining a flexible sheet with good moldability, it was possible to obtain a porous sheet having an extremely excellent function. That is, the present invention is one in which a non-moisture permeable or low moisture permeable sheet is partially laminated on a moisture permeable sheet, and the moisture permeable area of only the moisture permeable sheet portion, the moisture permeable sheet portion and the above By providing a porous sheet characterized in that the non-moisture-permeable or low-moisture-permeable sheet portion has multiple non-moisture-permeable or low-moisture-permeable regions in multiple layers alternately and in multiple rows, the above object is achieved. It has been achieved.

As the above-mentioned porous sheet, a sheet material of the composition (a) comprising 100 parts by weight of a polyolefin resin, 50 to 400 parts by weight of a filler and 0.1 to 20 parts by weight of a softening agent, and A porous sheet obtained by partially laminating and stretching a sheet-like material of a composition (b) comprising 100 parts by weight of a resin, 0 to 40 parts by weight of a filler, and 0 to 10 parts by weight of a softening agent, The single layer sheet area of the moisture permeable sheet formed of the composition (a) by a stretching treatment and the non-moisture permeable or low moisture permeable sheet formed of the moisture permeable sheet and the composition (b) are multilayered. There is a multi-layered sheet area which has become alternately and in multiple rows. In the method for producing a porous sheet according to the present invention, the composition (a) and the composition (b) are coextruded to form the composition (b) on the composition (a). It is characterized in that a sheet-like material that is laminated physically is formed, and the formed sheet is stretched.

The porous sheet and the method for producing the same according to the present invention will be described in detail below. The porous sheet according to the present invention comprises a moisture permeable sheet and a non-moisture permeable or low moisture permeable sheet, and the polyolefin resin of the compositions (a) and (b) mainly used for these sheets is ethylene, propylene or the like. Homopolymers or copolymers of the above olefins can be used without particular limitation.
Medium- and low-density polyethylene called medium-density polyethylene and linear low-density polyethylene are preferable, and the density is particularly 0.
910 to 0.940 g / cm ³ and MFR 0.1 to 10 g
/ 10 min, preferably 0.1 to 5 g / 10 min linear low density polyethylene is preferably used. Further, it is also preferable to mix two or more kinds of the above-mentioned polymers or copolymers of the present invention, and in particular, 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 prepared by blending a copolymer of ethylene with 0 g / cm ³ and another α-olefin (hereinafter also referred to as a soft resin) is used, the porous sheet obtained has a moisture permeability. Since it is imparted with flexibility without damage, it is particularly excellent in tensile and tear strength. The soft resin is generally used in an amount of 20 parts by weight based on 100 parts by weight of the crystalline polyolefin resin.
-100 parts by weight are blended. In addition, you may mix | blend resin other than polyolefin within the range which does not lose the characteristic of polyolefin resin.

The filler used in the present invention is not limited,
Fillers usually mixed in rubber or plastic, such as calcium carbonate, gypsum, calcium sulfate, calcium phosphate, magnesium carbonate, magnesium sulfate, hydrated silicic acid, silicic acid 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, phenol resin, epoxy resin, thermosetting resin such as sodium polyacrylate, resin obtained by crosslinking thermoplastic resin such as polyethylene, polypropylene, polyacrylic ester by radiation etc., resin higher than the above molding (sheeting) temperature, etc. Organic substances can be mentioned. These fillers are 50 μm or less, preferably in the range of 0.05 to 30 μm, particularly 0.1 to 5 μm.
It is desirable to use it as a powder or granular material having an average particle diameter of the order of magnitude. When using a filler having an average particle size that is too large,
If the density of the pores of the obtained stretched sheet is lowered, and if a filler having an average particle size that is too small is used, stretching unevenness is likely to occur and a good porous sheet cannot be obtained.

The blending amount of the filler in the composition (a) is
50-40 with respect to 100 parts by weight of polyolefin resin
0 parts by weight, preferably 60 to 300 parts by weight, 50
When it is less than 100 parts by weight, the number of communicating holes in the moisture permeable region of the obtained porous sheet is small, so that the moisture permeability becomes small, and when it is more than 400 parts by weight, it becomes difficult to form and stretch the sheet-like material. Further, the compounding amount of the filler in the composition (b) is 0 to 40 parts by weight, preferably 0 to 20 parts by weight, relative to 100 parts by weight of the polyolefin-based resin,
In the case of 0 parts by weight, a non-moisture permeable or low moisture permeable region of the porous sheet can be obtained as a completely non-moisture permeable region or a region close to it.
If it exceeds 40 parts by weight, the film strength and heat sealability will be deteriorated.

The softening agent used in the present invention is not particularly limited, but is usually a plasticizer or lubricant 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 compound. One of an alcohol monoester or polyester, an aliphatic polycarboxylic acid and polyalcohol polyester, a monocarboxylic acid and / or polycarboxylic acid and monoalcohol and / or polyalcohol polyester, and an alcohol and / or carboxylic acid Partial ester or polyester, aliphatic amide,
Aromatic amide, metal soap of fatty acid, metal soap of aromatic carboxylic acid, polybutadiene oligomer, polybutene oligomer, isobutylene oligomer, isoprene oligomer, petroleum resin, coumarone resin, ketone resin, chlorinated parisin, silicone oil, liquid paraffin, polyethylene wax Etc.

The content 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 blending amount is determined by the affinity of the softening agent with polyolefin, the affinity with the filler, and the flexibility required for the porous sheet, but if the amount is less than 0.1 parts by weight, the softening effect is substantially lost. If the amount is more than 20 parts by weight, bleeding out occurs on 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 with respect to 100 parts by weight of the polyolefin resin,
It is particularly preferable to add 0 to 7 parts by weight. The blending amount is determined by the affinity of the softening agent with polyolefin, the affinity with the filler, and the flexibility required for the porous sheet, but when it exceeds 10 parts by weight, bleeding out on the sheet surface causes stickiness and adhesion. It becomes defective.

As the method for producing the above-mentioned porous sheet according to the present invention, the following method is used in addition to forming the composition (b) in a multi-layer on a part of the sheet-like material of the composition (a) and stretching the composition (b). is there. For example, a sheet-like material made of the composition (a) or the like, which is formed by stretching a sheet-like material made of the composition (a) or the like and forming a non-moisture-permeable sheet layer by an emulsion or solution coating method. There is a sheet formed by appropriately laminating a stretched non-moisture permeable sheet on a stretchable moisture permeable sheet. The method for laminating a moisture impermeable sheet on a sheet material before stretching or the method for laminating a moisture permeable sheet after stretching may be a coating method or a laminating method of the above emulsion or solution. In the present invention, a method in which the composition (b) is laminated in a part of the sheet-shaped material of the composition (a) by the above-mentioned coating method, but especially a laminate is formed and stretched is shown. With such a constitution, the molding of the sheet-like material and the stretching thereof can be achieved very easily. In addition, the obtained porous sheet can be obtained as a porous sheet which is excellent in tensile strength, heat sealability, and adhesive strength of the seal portion while maintaining moisture permeability and water pressure resistance.

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

Moisture Permeation of Moisture Permeation Sheet Composed of Composition (a)
The degree is 0.4-6g / 100cm²Hr, particularly preferably
0.8-4g / 100cm²・ It is Hr. Also the composition
A moisture-permeable sheet made of (a) and a non-permeable sheet made of the composition (b).
Non-moisture permeable or low moisture permeable sheet with multiple layers
The moisture permeability of the low moisture permeability range is 0-0.3g / 100cm²・ H
r, particularly preferably 0.01 to 0.2 g / 100 cm²・ H
r. The moisture permeability of the single layer sheet part of the moisture permeable sheet
0.4g / 100cm²・ If it is less than Hr, it is effective for preventing unevenness.
Fruit is inferior, and conversely its moisture vapor transmission rate is 6g / 100cm.²・ Hr
If it exceeds, the water pressure resistance will decrease and the leakproof property will decrease. multilayer
Moisture vapor transmission rate of the sheet is 0.3g / 100cm ²・ Over Hr
Adhesive strength and tensile strength decrease, and the heat seal
Strength also decreases.

According to the porous sheet having the above-mentioned structure, the single-layer sheet region composed of the composition (a) and the composition (a) are used.
Since the multi-layered sheet region composed of the composition (b) and the composition (b) are alternately present in multiple rows, the single-layered 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 multi-layered sheet area consisting of the product (a) and the composition (b), and the moisture permeability, water pressure resistance, heat sealability, and adhesion are comprehensively evaluated. A sheet having excellent properties and tensile strength is obtained, and it is suitable as a back material for absorbent articles such as sanitary napkins, disposable diapers, and wound dressings described below.

FIG. 1 is a perspective view showing an embodiment of an absorbent article using a porous sheet according to the present invention as a backing material, with the absorbent article partially cut away. Also, FIG.
(A) is a plan view of a backing material used for an absorbent article,
(B) is sectional drawing which follows the ee line of FIG. (A), (c) is sectional drawing which follows the same ff line. FIG. 3 shows an embodiment of a method for producing a porous sheet according to the present invention, and FIG. 3 (a) is a sectional view of a sheet before stretching by an inflation method, and FIG.
(B) is a cross-sectional view of the cut sheet of (a).

FIG. 1 shows a sanitary napkin 1 which is one of the absorbent articles. The sanitary napkin 1 includes a liquid-permeable surface material 2 and a leak-proof back surface material 4. The absorbent body 3 is arranged between these double-sided materials. As shown in FIG. 2, the backing material 4 of the sanitary napkin 1 (generally 50 to 150 mm wide) has a non-permeable area 4B and a transparent area 4 as shown in FIG.
The above-mentioned porous sheet composed of A and A is used, and the positional configuration of the permeable region of the porous sheet in the application is as follows: non-permeable region 4B-permeable region 4A-non-permeable region 4B-permeable Area 4A-non-permeable area 4B, non-permeable area 4B-permeable area 4A
-The structure of the non-permeable region 4B is preferable, and the ratio of the non-permeable region 4B is 95 to 7 at both ends in the length direction of the napkin.
It is particularly preferable that 0% and 5 to 30% occupy the central portion.

Also, disposable diapers (generally 200-
In the case of 600 mm width), the number of repetitions of non-transparent region 4B-transparent region 4A-non-transparent region 4B ...- Transparent region 4A-non-transparent region 4B is selected depending on the size / shape. .
In the case of a diaper, it is preferable that the front end portion in contact with the fastening tape has a ratio of the non-permeable area 4B close to 100%. The absorbent article configured as described above does not leak absorbed body fluid, and easily vaporizes and releases the fluid,
It does not get stuffy and gives a comfortable fit.

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 a 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 molded into pellets. In such preparations, small amounts of stabilizers, colorants,
Alternatively, the lubricant can be mixed simultaneously or separately.

The method for producing a sheet-like product in which the above composition (a) / composition (b) is partially constituted in multiple layers is not particularly limited, but coextrusion molding using two or more extruders is preferable. In the case of coextrusion, the moisture permeable region 4A-non-moisture permeable region 4B
-Moisture permeable region 4A-Even if the number of repetitions increases, it is easily determined by die manufacturing. Also, the area ratio in the molding direction can be changed sequentially or repeatedly so that the die structure and the extruder discharge. It is decided by the amount control, and thereafter, the two compositions are fed from two extruders, so that the burden on the production is not increased at all.

There are an inflation method (circular die method) and a T-die method (flat die method) as methods for forming a coextrusion molded sheet, 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. which is the melting point of the polyolefin resin in the inflation method.
A high temperature is preferable, and in the case of the T-die method, it is 20 to 50.
Temperatures higher by ° C are preferred. FIG. 3 shows a multilayer sheet material according to the present invention manufactured by the inflation method.

As the roll stretching method for the sheet-like material, uniaxial stretching or uniaxial stretching is followed by successive biaxial stretching in the transverse direction by a tenter stretching machine, an air inflation stretching machine, a mandrel stretching machine or the like, or simultaneous longitudinal and longitudinal stretching. A method of stretching in the transverse direction is adopted. The stretching temperature is generally room temperature or higher and not higher than the melting point of the polyolefin resin, particularly preferably 10 ° C. lower than the melting point. The stretching ratio is at least 1.2 times and 4 times or less in at least one uniaxial direction, that is, in the longitudinal (MD) direction in the case of uniaxial stretching, and in the longitudinal (MD) and transverse (TD) directions in the case of biaxial stretching. It is preferable that the ratio is 1.2 times or more and 4 times or less, respectively, in order to maintain the mechanical balance and strength, and at the same time exhibit excellent moisture permeability and water pressure resistance. Further, generally, it is preferable that after the stretching step, a heat treatment is performed under tension, and then the sheet is cooled to a room temperature below the stretching temperature and taken out. Further, surface treatment such as corona discharge treatment may be performed in order to improve printability and adhesive strength of the sheet.

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, and by the subsequent stretching treatment. The region composed of only 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 moisture impermeable region 4B.
The moisture permeable region can be easily provided at a desired position of the porous sheet, and the heat seal strength can be easily given to a necessary portion.

[0024]

【Example】

Preparation of composition: 100 parts by weight of linear low-density polyethylene (Ultzex 2520F, Mitsui Petrochemical Industry Co., Ltd.) and 150 parts by weight of surface-treated calcium carbonate (average particle size 1.1 μm) were added to the composition (a). , And polyester (trimethylolpropane / adipic acid / stearic acid = 2
Mol / 1 mol / 4 mol SV = 240, AV =
1, OHV = 8) 5 parts by weight Composition (b) of 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 polyester (same as for composition (a)) 0.3 parts by weight The above compositions were mixed in a 100-liter Henschel mixer, and then kneaded into pellets by a twin-screw extruder having a diameter of 45 mm.

Sheet molding: 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 as an extruder for the composition (b) (hereinafter, referred to as an extruder). ,
b) is used, and the sheet width after cutting is 30 using a coextrusion circular die known per se under the following molding conditions.
A 0 mm partial multilayer sheet was molded (same pattern as in FIG. 3). Die diameter φ60 mm, die lip clearance = 1 mm Cylinder temperature (° C) Die temperature (° C) Take-up speed a Extruder 160-170-175 180 10 m / min b Extruder 160-170-175

Stretch molding: A roll stretching machine having a diameter of 200 mm and a width of 300 mm was used, and the thickness was 6 when connected to the sheet molding machine.
A 0 μm sheet was stretched 2.3 times at 80 ° C. The sheet pattern after stretching is the same as that in FIG. 2A, and in FIG. 2B, 4B has a width of 50 mm, a length of about 40 mm, and a thickness of about 8 μ.
Width 10 mm, length 100 mm, thickness about 10 μm in part (c),
The length from the ee portion to the ff portion was 90 mm. Also,
The thickness of the sheet was about 40 μm.

Comparative Example Using the pellets of the composition (a) of the above-mentioned example, a sheet having a thickness of 60 μm was formed at the same temperature and take-up speed as in the example with an ordinary inflation film forming machine under the same conditions as the example. Was stretched. The obtained sheet thickness was about 40 μm (FIG. 4).

(Evaluation criteria) (1) Water vapor transmission rate: 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-
Nonwoven fabrics composed of polypropylene composite fibers and having a basis weight of 20 g / m ² were superposed, and the ends thereof were used with a single-sided heating bar sealer (seal bar 10 × 30 mm) manufactured by Tester Sangyo Co., Ltd., pressure 2 kg / cm ² , time 0. 0.5sec, temperature 130 ℃
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 that are all good ・ ・ ・ ・ ・ ・ ・ ・ ○ ・ Samples with some heat shrinkage ・ ・ ・ ・ △ ・ Samples with weak adhesion and large heat shrinkage ×

(5) Adhesiveness of tape: 20 for a porous sheet
Apply hot melt adhesive with a thickness of μm (20mm width x 1
(50 mm length), and this is laminated with a cotton cloth and pressure-bonded by reciprocating once with a 5 kg roller to obtain a test sample. In this sample, the transfer of the pressure-sensitive adhesive to the cotton gold cloth when the cotton gold cloth was peeled from the porous sheet was judged according to the following criteria, and the tape adhesiveness of the sheet was determined.・ No transfer of adhesive is observed at all ・ ・ ・ ○ ・ Some transfer of adhesive is observed ・ ・ △ ・ Most of the adhesive is transferred ・ ・ ・... ×

(6) Moisture: Polyethylene as backing material
-Polypropylene composite fiber basis weight 20 g / m ²of
Nonwoven fabric as absorber, basis weight 260 g / m²Made of cotton
As shown in Fig. 1, the porous pulp and porous sheet are used as the backing material.
It constitutes a sanitary napkin. This sample of 10
Have it worn on the monitor and evaluate the stuffiness according to the following criteria
I paid.・ There is no stuffiness and a refreshing feeling ・ ・ ・ ・ ○ ・ Slight stuffiness ・ ・ ・ ・ ・ ・ ・ △ ・..... * Collectively the physical properties of the porous sheet obtained according to the above criteria.
The results are shown in [Table 1].

[0031]

[Table 1]

A sanitary napkin having the structure shown in FIG. 1 was manufactured using the porous sheets of the above-mentioned Examples and Comparative Examples. As a result, a conventional backing material (low density polyethylene laminated paper) was used.
In comparison with Comparative Example 1, there was no stuffiness, it was soft and had a dry feel, and it had better heat sealability, hot melt adhesiveness, tape adhesiveness, and sheet strength than the backing material of the Comparative Example, and was comfortable to wear.

[0033]

The porous sheet of the present invention is excellent in sheet strength and sealing property, and has moisture permeability, water pressure resistance and the like. In addition, an absorbent article using such a porous sheet as a backing material vaporizes and releases absorbed body fluid without leaking, giving a comfortable wearing feeling without stuffiness.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an absorbent part using a porous sheet according to the present invention, with a part of the absorbent article cut away.

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

FIG. 3 shows an example 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). Is.

FIG. 4 shows a comparative example, FIG. 4 (a) is a plan view showing a porous region of a (single layer) composed of the composition (a), and FIG. 4 (b) is II- of FIG. 4 (a). It is a sectional view taken along the line II (width direction).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Absorbent article 2 Surface material 3 Absorber 4 Back material 4A Moisture-permeable area | region consisting of a composition (a) 4B Non-moisture-permeable area | region consisting of a composition (b) 4A 'Sheet area | region consisting of a composition (a) 4B' composition Seat area consisting of item (b)

Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location A61F 5/44 H 7108-4C B29C 47/06 8016-4F 67/20 B 9268-4F B32B 3/16 7016- 4F 27/18 Z 6122-4F 27/20 Z 6122-4F 27/32 E 8115-4F // B29K 23:00 105: 04 B29L 9:00 4F

Claims (4)

[Claims] 1. A non-moisture-permeable or low-moisture permeable sheet partially laminated on a moisture permeable sheet, wherein the moisture permeable area of only the moisture permeable sheet portion, the moisture permeable sheet portion and the non-moisture permeable sheet portion A porous sheet characterized in that the moisture-permeable or low-moisture permeable sheet portion has a plurality of non-moisture-permeable or low-moisture permeable regions alternately arranged in multiple rows. 2. A sheet of the composition (a) comprising 100 parts by weight of a polyolefin 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 resin, A porous sheet obtained by partially laminating a sheet-like material of a composition (b) comprising 0 to 40 parts by weight of a filler and 0 to 10 parts by weight of a softening agent, and subjecting the composition to the stretching treatment. A multilayer sheet in which a single-layer sheet region of the moisture-permeable sheet formed of the article (a) and the moisture-impermeable or low-moisture-permeable sheet formed of the moisture-permeable sheet and the composition (b) are multilayered. The porous sheet according to claim 1, wherein the porous sheet has areas alternately and in multiple rows. 3. The method according to claim 2, wherein the composition (a) and the composition (b) are coextruded to partially form the composition (b) on the composition (a). 1. A method for producing a porous sheet, which comprises forming a sheet-like material laminated on a sheet, and stretching the formed sheet. 4. An absorbent article comprising a liquid-permeable front material, a leak-proof back material, and an absorber arranged between these double-sided materials, wherein the porous sheet according to claim 1 or 2. Is used as the backing material.