JPH08300500A - Porous sheet, manufacture thereof and absorptive article wherein the sheet is utilized - Google Patents

Abstract

PURPOSE: To give moisture permeability and water resistance to sheet and improve the strength of the sheet by a method wherein a plurality of ribs are provided in multiple rows at the predetermined intervals respectively in the longitudinal direction and in the lateral direction of the sheet so as to make each portion surrounded by the ribs into a concave surface part. CONSTITUTION: Porous sheet 1 consists of ribs 3 and 3' and concave surface parts 2 surrounded by the ribs 3 and 3'. In addition, the ribs 3 and 3' are formed in multiple rows in the longitudinal direction or the machine direction or the direction A and in the lateral direction or the cross direction or the direction normal to the direction A of the porous sheet 1. The thickness (b) of the rib 3 in the machine direction is made to be 0.5-4 times as much as the thickness (a) of the concave surface part 2 and the pitch (c) between the ribs 3 is preferably set to be 100μ-50mm and the width (d) of the rib 3 is preferably set to be 50μ-10mm. The preferable ranges of the thickness (b) of the rib 3', of the pitch (e) between the ribs 3' and of the width (f) of the rib 3' are made to be equal to those of the ribs arranged in multiple rows in the machine direction. Further, the thicknesses (b) of the ribs 3 and 3' are respectively and preferably set to be 10-400μ and the thickness (a) of the concave surface part 2 is preferably set to be 10-200μ. The deflection (m) of the concave surface part 2 is expressed by the distance between the line (r) and the lowermost point (z) on the rear surface side of the concave surface part 2 and is preferably set to be 15-40,000μ.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous sheet, a method for producing the same, and an absorbent article, which have excellent sheet strength.
The present invention also relates to a porous sheet having excellent moisture permeability and water pressure resistance, a method for producing the same, and an absorbent article using the porous sheet.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As the porous sheet, a sheet obtained by melt-mixing a crystalline polyolefin resin and an inorganic filler, shaping the sheet into a sheet, and then stretching the sheet in a uniaxial or biaxial direction, a crystalline polyolefin resin and melting of the resin An organic compounding agent that is miscible with the resin below and causes phase separation when cooled to a crystallization temperature of the resin or a temperature lower than that is melt-mixed and molded into a sheet, and then easily mixed with the organic compounding agent. A sheet obtained by extraction in a soluble extract, a sheet obtained by uniaxially or biaxially stretching with the organic compounding agent contained therein, or a sheet easily soluble in the organic compounding agent after stretching. Sheets and the like obtained by extraction in an extract are known. In addition, such a porous sheet is added with a plasticizer or the like for the purpose of flexibility and prevention of sharp noise (sound generated when the sheet is rubbed or rubbed), such as disposable diapers and sanitary napkins. Used as a backing material for absorbent articles.

However, in these absorbent articles,
A tape or the like for fixing the diaper is generally attached to the porous sheet as the backing material when the diaper is used, but in the conventional porous sheet, longitudinal uniaxial stretching, transverse uniaxial stretching or Even if it is obtained by either longitudinal or transverse stretching, neither the tensile strength nor the tear strength is sufficient, and the sheet is damaged during wearing or detaching without attaching the reinforcing tape to the fastening position of the fastening tape. There was a problem of doing. In addition, in order to reinforce the strength, Japanese Patent Publication No. 6-89
Japanese Patent Publication No. 163 and Japanese Patent Publication No. 6-89164 propose a method in which a sheet is provided with streaks in a striped pattern by embossing and then stretched in a direction intersecting with the streaks. It has not been possible to increase the tensile strength in a well-balanced direction, and it has not been possible to omit the reinforcing tape at the tape fastening portion.

Therefore, an object of the present invention is to provide a porous sheet which has moisture permeability and water resistance, is excellent in sheet strength, and has a good usability when used for absorbent articles and the like, and a method for producing the same. An object is to provide an absorbent article using the porous sheet.

[0005]

Means for Solving the Problems The inventors of the present invention have made extensive studies in order to solve the above problems. As a result, the sheet has ribs in the MD direction and the CD direction, and a concave surface portion surrounded by the ribs is formed. It was found that the porous sheet having the above can achieve the above object.

The present invention has been made based on the above findings, and has a plurality of ribs formed in multiple rows at predetermined intervals in the MD and CD directions of the sheet,
It is intended to provide a porous sheet in which each portion surrounded by the rib forms a concave portion.

The present invention also provides, as a preferable method for producing the above-mentioned porous sheet, a resin from a T die on one surface of a lattice pattern-shaped member having a lattice pattern and a large number of openings formed by the lattice pattern. The composition is extruded and then vacuum-sucked from the other surface side of the lattice pattern-shaped member to obtain the MD direction and the CD.
After forming a film having ribs in each direction, the film is cooled and solidified, and then reheated, and vacuum suction is again applied from the other surface side of the lattice pattern-shaped member to remove the portion surrounded by the rib. The present invention provides a method for producing a porous sheet that is simultaneously stretched in the MD and CD directions.

Further, the present invention provides an absorbent article comprising a liquid-permeable surface material, a leak-proof back surface material, and an absorber arranged between them, wherein the surface material is the above-mentioned material. An absorbent article characterized by using a porous sheet.

First, the porous sheet of the present invention will be described in detail below. Examples of the material for forming the porous sheet of the present invention include the following resin compositions and the like. Composition: A composition comprising 100 parts by weight of a crystalline polyolefin resin, 30 to 400 parts by weight of a filler, and 0.1 to 20 parts by weight of a softening agent. Composition: 30 to 90 parts by weight of a crystalline polyolefin resin, 70 to 10 parts by weight of an organic compounding agent that is miscible with the crystalline polyolefin above the melting point of the crystalline polyolefin and dissolves, but causes phase separation below the melting point. Composition consisting of parts.

The above-mentioned crystalline polyolefin resin used in the above-mentioned composition is one having, as a main component, a monoolefin polymer or copolymer such as ethylene, propylene, butene, and linear low density polyethylene, homopolypropylene, Examples thereof include high density polyethylene, low density polyethylene, block copolymer polypropylene, random copolymer polypropylene, polybutene, ethylene-vinyl acetate copolymer, and mixtures thereof.

As the filler used in the composition, inorganic and organic fillers are used. Calcium carbonate, gypsum, talc, clay, kaolin, silica, diatomaceous earth, magnesium carbonate, barium carbonate, magnesium sulfate, sulfuric acid. Examples thereof include barium, calcium phosphate, aluminum hydroxide, zinc oxide, titanium oxide, alumina, mica, zeolite, carbon black, wood powder and pulp. Further, the calcium carbonate or the like may be surface-treated by hydrophobizing the surface with a fatty acid or a metal salt thereof.

Examples of the softening agent used in the composition include polyesters and hydrocarbon polymers. The polyester is a polyester having a polybasic acid or a polyhydric alcohol as a constituent component, and examples thereof include a trimethylolpropane / adipic acid / stearic acid polyester.

The crystalline polyolefin resin used in the composition is the same as the crystalline polyolefin resin used in the composition.

The above-mentioned organic compounding agent used in the above-mentioned composition is not particularly limited as long as it has the above-mentioned characteristics. Preferred examples thereof include triethylene glycol, dibutyl phthalate, and esters of phthalic acid, trimellitic acid, pyromellitic acid and / or aliphatic polybasic carboxylic acid with an alkyl alcohol.

Thus, the porous sheet of the present invention has a plurality of ribs formed in multiple rows at predetermined intervals in the longitudinal direction (MD direction) and the lateral direction (CD direction) of the sheet. , Each portion surrounded by the rib forms a concave surface portion. The "predetermined interval" can be represented by the pitch between the ribs. This pitch will be described later.

The porous sheet of the present invention will be described in more detail with reference to FIGS. 1 and 2. Here, FIG. 1 is an enlarged perspective view showing an enlarged main part of the porous sheet of the present invention, and FIG. 2 is a sectional view taken along the line AA of the porous sheet shown in FIG. FIG. 3 is an enlarged view of part III in FIG.

The porous sheet 1 of the present invention shown in FIGS. 1 and 2 comprises ribs 3 and 3'and a concave surface portion 2 surrounded by the ribs 3 and 3 '. The ribs 3 are formed in multiple rows along the MD direction (the direction of the arrow in FIG. 1) of the porous sheet 1, and the ribs 3 ′ are C of the porous sheet 1.
It is formed in multiple rows along the D direction (direction perpendicular to the arrow in FIG. 1). That is, the ribs 3 and 3'form a lattice pattern, and the concave portion 2 is formed so as to be surrounded by each lattice. Here, the “rib” means, as shown in FIG.
It refers to a portion (hatched portion in the figure) located above a line r connecting the bottoms y of the respective convex portions of the porous sheet. Although FIG. 3 shows the rib 3, the same applies to the rib 3 ′. Therefore, the widths d and f of the ribs 3 and 3 '
Is the width of the shaded portion, that is, the width of the intersection of the line r and the sheet surface. Also, the thickness b of the ribs 3, 3 '
Is the distance between the top x and the bottom y of the rib.
Further, the “concave surface portion” means a portion located below the line r.

In the porous sheet of the present invention, the ribs 3 and 3'are formed so as to intersect each other and form a lattice-like pattern as a whole.
Here, the intersection angle Θ between the rib 3 and the rib 3 ′ is 1 to
It is preferably 90 °, and more preferably substantially right angle. Further, the ribs 3 and 3 ′ do not have to be parallel to the MD direction or the CD direction, and ribs parallel to each other in multiple rows may be formed at an angle of 1 to 90 °.

As shown in FIG. 2, the thickness b of the ribs 3 formed in multiple rows in the MD direction is preferably in the range of 0.5 to 4 times the thickness a of the concave surface portion 2, It is more preferable that the range is 1 to 2 times. If the thickness b of the rib 3 is less than 0.5 times the thickness a of the concave portion 2, sufficient strength cannot be obtained, and if it exceeds 4 times, the flexibility is impaired, which is not preferable. The pitch c between the ribs 3 formed in multiple rows in the MD direction is preferably 100 μm to 50 mm, more preferably 1 mm to 5 mm.
If the pitch c exceeds 50 mm, sufficient strength cannot be obtained, and if it is less than 100 μ, flexibility is impaired, which is not preferable. The width d of the ribs 3 formed in multiple rows in the MD direction is preferably 50 μ to 10 mm, more preferably 0.5 to 2 mm. Above d
Is less than 50 μ, sufficient strength cannot be obtained and 10 m
When it exceeds m, flexibility is impaired, which is not preferable.

The thickness b of the ribs 3'formed in multiple rows in the CD direction, the pitch e between the ribs 3 ', and the ribs 3'.
The preferable range of the width f is the same as the preferable range of the rib formed in multiple rows in the MD direction described above, but different from the thickness b, the pitch c, and the width d of the rib 3 in the MD direction. They may be the same or the same. In addition, if it is less than the lower limit of the range or exceeds the upper limit of the range, it is not preferable for the same reason as the reason for the rib formed in multiple rows in the MD direction.

The thickness b of each of the ribs 3 and 3'formed in multiple rows in the MD direction and the CD direction is preferably 10 to 400 .mu.m. Further, the thickness a of the concave surface portion 2 is preferably 10 μ to 200 μ.

Further, the concave surface portion 2 in the porous sheet of the present invention is a portion surrounded by the rib 3 and the rib 3 ', and is formed in a concave shape uniformly along the rib 3 and the rib 3'. It is what Deflection m of the concave portion 2
Is expressed by the distance between the line r and the lowermost point z on the back surface side of the concave portion 2, as shown in FIG. 2, preferably 15 to 4000 μm, and more preferably 20 to 2000 μm. .

The thicknesses b and widths d of the ribs 3 and 3'formed in multiple rows in the MD direction and the CD direction,
f and the deflection m of the concave surface portion 2 can be appropriately adjusted depending on the line width of the lattice pattern-shaped member described below, the stretching condition of the concave surface portion 2, and the like.

In the present invention, only the concave surface portion 2 is
It is preferably stretched in the MD direction and the CD direction and has moisture permeability. That is, the porous sheet 1 of the present invention
Is a non-moisture permeable rib 3, 3 ', MD direction and CD
It is preferred that the concave surface portion 2 be stretched in the direction and have moisture permeability.

Next, a preferred method for producing the porous sheet of the present invention will be described with reference to FIGS. 4, 5 (a) and 5 (b). Here, FIG. 4 is a schematic view showing a manufacturing apparatus used in the method for manufacturing a porous sheet of the present invention. 5 (a) is an enlarged plan view of the plain weave net as the lattice pattern-shaped member shown in FIG. 4, and FIG.
FIG. 6 is a BB cross-sectional view of the plain weave net shown in FIG.

First, the manufacturing apparatus 100 shown in FIG. 4 will be described. The manufacturing apparatus 100 includes an extruder 10 including a T die 11 for extruding the molten resin composition 1 ″,
Plain weave net 2 as a lattice pattern-shaped member for imparting a predetermined pattern to the resin composition 1 ″ extruded from the extruder 10.
0 and the suction nozzle 31 from the other side of the plain weave net 20.
Vacuum suction of the resin composition 1 ″ via a vacuum pump to form a film 1 ′ having a predetermined pattern (the above ribs) formed thereon, and vacuum suction with the vacuum pump 30 and then reheating And the suction nozzle 51 from the other side of the plain weave net 20 after being heated by the heater 40.
A vacuum pump 50 for vacuum-sucking the film 1'through a predetermined shape (the above-mentioned concave portion), and a cooling roll 60 for cooling the sheet on which the rib and the concave portion are formed, A winder 80 for winding the porous sheet 1 formed by passing through the cooling roll 60, and a guide roller 7.
It consists of 0, 71, and 72.

More specifically, the plain weave net 20 is used.
Has a lattice pattern 21 and a large number of apertures 22 formed by the lattice pattern 21.
Are arranged in parallel and in multiple rows (M of the porous sheet above).
A large number of wire rods 2 arranged in the direction corresponding to the D direction)
3 and a large number of wire rods 24 woven in the wire rods 23 so as to be orthogonal to the wire rods 23 and in multiple rows (toward the direction corresponding to the CD direction of the porous sheet). The plain weave net 20 is in the form of a belt conveyor so that the resin composition 1 ″, the film 1 ′ and the sheet can be conveyed in the direction of the arrow. Here, the line pitch of the nets 23 and 24. i, l and the above net 2
The line widths (wire diameters) h and k of 3, 24 are the ribs 3,
It is optional depending on the pitches c and e and the widths d and f of 3 '.
The material for forming the wires 23, 24 is not particularly limited as long as it does not deform even when the molten resin composition and the film are placed, but metal or the like is preferably used.

Further, the suction nozzle 31 is provided above the conveyor formed by the plain weave net 20 so that the resin composition 1 ″ extruded onto the plain weave net 20 can be vacuum-sucked in a molten state. On the side, the plain weave net is arranged so as to abut on the other surface side, and the heater 40 is a suction nozzle connected to the vacuum pump 50 by melting the film 1 ′ that has been cooled and solidified. 51 allows simultaneous drawing in the MD direction and the CD direction so that the concave portion 2 can be shaped, and is located behind the suction nozzle 31 and in the plain weave net 2
It is provided above the conveyor formed by 0. In addition, the size of the extruder 10 and the T die 11,
The width and length of the plain weave net 20 are arbitrary depending on the desired size of the porous sheet.

In order to carry out the method for producing a porous sheet of the present invention, as shown in FIG. 4, the resin composition 1 ″ is extruded from the T die 11 onto one surface of the plain weave net 20. Further, vacuum suction is performed from the other side of the plain weave net 20 by the vacuum pump 30 to form a film 1'having ribs 3 and 3'formed in the MD direction and the CD direction respectively, and then the film 1'is formed. After being cooled and solidified, it is reheated by the heater 40 and vacuum sucked again by the vacuum pump 50 from the other surface side of the lattice pattern-shaped member to MD the portion surrounded by the ribs 3 and 3 '. It can be performed by stretching in the machine direction and the CD direction.

Specifically, the set temperature of the T die is 15
The temperature is preferably 0 to 240 ° C. The extruded resin composition 1 ″ is conveyed in the direction of the arrow as the conveyor-like plain weave net 20 rolls in the direction of the arrow, passes through the suction nozzle 31, is formed into a film, and is sucked. A sheet is formed by passing through the nozzle 51. The rolling speed of the plain weave net 20 at this time corresponds to the take-up speed of the porous sheet 1, and the take-up speed is 5 to 300 m / min. Moreover, the vacuum suction by the vacuum pump 30 is performed by the resin composition 1 ″.
Is performed in the molten state, and the vacuum degree V at this time is
1 is optional depending on the desired thickness b of the ribs 3, 3 '. Then, by appropriately changing the degree of vacuum V1, the thickness b of the ribs 3, 3'in the obtained porous sheet can be adjusted. In addition, the above vacuum pump 3
The cooling and solidification performed after the vacuum suction by 0 can be performed by natural heat dissipation or a forced cooling fan. At this time, the temperature of the film is preferably 10 to 100 ° C.,
More preferably, the temperature is set to 20 to 50 ° C. The heating by the heater 40 can be performed by blowing hot air at 200 to 300 ° C., for example. At this time, the temperature of the film is preferably 30 to 150 ° C., and 50 to 50 ° C.
More preferably, the temperature is 100 ° C. The vacuum suction by the vacuum pump 50 is performed while the film 1 ′ can be stretched by the heater 40.
The degree of vacuum V2 at this time is arbitrary depending on the desired thickness a and the deflection m of the concave surface portion 2, but the conditions such that the stretching ratio in the simultaneous stretching is 1 to 8 in both MD and CD directions. It is preferable to perform vacuum suction. By appropriately changing the degree of vacuum V2, it is possible to adjust the thickness a and the deflection m of the concave surface portion of the obtained porous sheet, and the thickness b of the ribs 3 and 3'in the porous sheet.

Then, the obtained sheet is cooled by a cooling roll 60.
To cool the guide rollers 70, 71, 72.
The porous sheet 1 obtained through the above can be wound up by a winder 80 or the like and supplied to various manufacturing processes of molded articles.

In this manner, the resin composition 1 "is extruded onto the plain weave net 20 and then vacuum-sucked, so that the lattice pattern 21 of the plain weave net 20 causes the protrusions (that is, the protrusions corresponding to the lattice pattern 21). , The rib 3,
A film 1 ′ on which 3 ′) has been formed is obtained. Further, by vacuum suctioning the obtained film 1 ′ from the other surface side of the plain weave net 20, the plain weave net 20 is obtained.
By forming the concave surface portion 2 corresponding to the opening hole 22 of the above, a sheet having the ribs 3, 3 ′ and the concave surface portion 2 is obtained, and the porous sheet is provided via the cooling roll 60. 1 is obtained.

In the present embodiment, the plain weave net is described as an example of the lattice pattern-shaped member, but
Without being limited to this, a twill net, a plate having apertures surrounded by lattice-like ridges and ridges, and the like can be used.

By manufacturing in this manner, it is preferable that only the concave surface portion 2 is stretched and only the concave surface portion 2 has moisture permeability. Further, although the rib may be stretched, the rib does not have moisture permeability. Only the concave surface portion 2 can be stretched by adjusting the conditions of the heating and the vacuum suction. In the porous sheet of the present invention, only the portions where the ribs 3 and 3'are not arranged, that is, only the concave surface portions 2 are stretched, and only the portions where the ribs are not formed have moisture permeability. preferable. Further, since the porous sheet of the present invention has ribs with high strength,
This sheet has high tensile and tear strengths in both longitudinal and lateral directions. Further, in particular, by having the concave portion 2, it is possible to obtain a velvety sheet which is very soft and has an excellent texture. Therefore, the porous sheet of the present invention is suitable as a backing material for absorbent articles such as sanitary napkins and disposable diapers, and can also be used for filters, medical materials, and clothing materials.

Next, the absorbent article of the present invention will be described. The absorbent article of the present invention comprises a liquid-permeable front material, a leak-proof back material, and an absorber arranged between them. Such a configuration and the material for forming the surface material and the absorber and the like are the same as the conventionally known configuration and material. Thus, in the absorbent article of the present invention, the porous sheet of the present invention is used as the back material. The absorbent article of the present invention includes sanitary napkins, disposable diapers for adults or infants, incontinence pads, and the like, and the porous sheet is used in a desired shape depending on the application of the absorbent article. To be

[0036]

EXAMPLES Next, the porous sheet of the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

[Example 1 and Example 2] In Example 1, the following composition A was used, and in Example 2, the following composition B was used, and the following extruder and the following plain weave net were used to produce the production apparatus shown in FIG. Then, it was molded under the following molding conditions to obtain a porous sheet.

(Composition) Composition A: Linear low-density polyethylene [trade name "Ultzex 2520F" manufactured by Mitsui Petrochemical Industries, Ltd.) 100 parts by weight Surface-treated calcium carbonate (1.1 μm) 150 parts by weight Polyester ( Trimethylolpropane / avidic acid / stearic acid = 2 mol / 1 mol / 4 mol 5 parts by weight Composition B: Polypropylene (M1 = 0.5, density = 0.91) 100 parts by weight Paraffin oil (density = 0. 87) (made by Idemitsu Kosan, trade name "PW3 80") 40 parts by weight

(Extruder) Extruder equipped with a T-die; 50φ mm single-screw extruder (plain weave net) Line width (line diameter); 0.6 mm Line pitch; 2.0 mm

[Molding conditions]; Set temperature; Composition A ... 180 ° C. Composition B ... 210 ° C. Take-up speed: 16 m / min Draw ratio: 2.2 times

The shapes of the porous sheets obtained in Examples 1 and 2 were as follows: thickness of concave portion was 40 μ, deflection of concave portion was 1200 μ, rib thickness was 60 μ, pitch between ribs was c. , E is 2.0 mm and rib widths d and f are 0.6 mm
Is. The following 1) to 4) tests were performed and evaluated on these porous sheets according to the following evaluation criteria. The results are shown in [Table 1].

[Evaluation Criteria] 1) Water vapor transmission rate: Measured according to JIS ZO 208 2) Water pressure resistance: Measured according to JIS L 1093B method 3) Tensile strength: Stretching direction and direction perpendicular to the stretching direction Sheets each having a width of 10 mm were subjected to a Tensilon tensile tester and measured at a chuck distance of 50 mm and a tensile speed of 300 mm / min. 4) Tear strength: Cut a piece of 60 mm × 30 mm so that its long side is equal to the stretching direction of the sheet, and further cut in parallel with the long side from the center of the above piece to one end of the short side with a razor blade. It was used as a sample. Then, using a Tensilon tensile tester, the two ends formed by cutting the sample were fixed to a chuck, the sample was T-shaped, and the tear measurement in the sheet stretching direction was performed at a tensile speed of 300 mm / min. The average load was determined from the obtained measurement chart and used as the tear strength.

[Comparative Example 1 and Comparative Example 2] A porous sheet having no rib was prepared in the same manner as in Example 1 and Example 2, except that a normal T-die film forming machine which did not use a plain weave net was used. Got The obtained porous sheet was tested in the same manner as in Example 1 and Example 2. The results are shown in [Table 1].

[0044]

[Table 1]

[0045]

INDUSTRIAL APPLICABILITY The porous sheet of the present invention has moisture permeability and water pressure resistance, is excellent in sheet strength, and has a good feeling when used in absorbent articles and the like. Further, according to the method for producing a porous sheet of the present invention, the above-mentioned porous sheet can be easily produced. Further, since the absorbent article of the present invention uses the above-mentioned porous sheet as a backing material, even when there is no reinforcing tape in the tape fastening portion, even when it is adhesively fixed with a tape or the like during use, it is worn or removed. Moreover, the sheet is not torn, and the tape can be attached and removed at any position, which is excellent in usability.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view showing an enlarged main part of a porous sheet of the present invention.

2 is a cross-sectional view taken along the line AA of the porous sheet shown in FIG.

FIG. 3 is an enlarged view of a part III in FIG.

FIG. 4 is a schematic view showing a manufacturing apparatus used in the method for manufacturing a porous sheet of the present invention.

5 (a) is an enlarged plan view of the plain weave net shown in FIG. 4, and FIG. 5 (b) is a BB cross-sectional view of the plain weave net shown in FIG. 5 (a).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Porous sheet 1'Film 1 '' Resin composition 2 Concave part 3,3 'Rib 10 Extruder 11 T die 20 Plain weave net 21 Lattice pattern 22 Open hole 23,24 Wire rod 30,50 Vacuum pump 31,51 Suction nozzle 40 Heater 60 Cooling Roll 70,71,72 Guide Roller 80 Winder 100 Manufacturing Equipment

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display area B29K 105: 04 B29L 7:00 C08L 23:02

Claims (6)

[Claims] 1. A sheet has a plurality of ribs formed in multiple rows at predetermined intervals in the MD direction and the CD direction, and each portion surrounded by the ribs forms a concave surface portion. Porous sheet. 2. The porous sheet according to claim 1, wherein only the concave surface portion is stretched in the MD direction and the CD direction and has moisture permeability. 3. The porous sheet according to claim 1, wherein the thickness of the rib is in the range of 0.5 to 4 times the thickness of the concave surface portion. 4. The porous sheet according to claim 1, wherein the ribs have a width of 50 μm to 10 mm and the ribs have a pitch of 100 μm to 50 mm. 5. The method for producing a porous sheet according to claim 1, wherein a T-die is formed on one surface of the lattice pattern-shaped member having a lattice pattern and a large number of openings formed by the lattice pattern. The resin composition is extruded, and then vacuum suction is performed from the other surface side of the lattice pattern-shaped member to form a film having ribs in the MD direction and the CD direction respectively, and then the film is cooled and solidified and then reheated. At the same time, a method for producing a porous sheet in which the portion surrounded by the ribs is simultaneously drawn in the MD direction and the CD direction by vacuum suction again from the other surface side of the lattice pattern-shaped member. 6. An absorbent article comprising a liquid-permeable surface material, a leak-proof back surface material, and an absorber arranged between them, wherein the surface material is the surface material. An absorbent article comprising a porous sheet.