JP5833418B2 - Nonwoven fabric and absorbent article sheet material - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a nonwoven fabric containing main fibers and a binder component, which has excellent tensile strength and permeation resistance despite its small basis weight, and a sheet material for absorbent articles using the nonwoven fabric. Is.

  Conventionally, as a sheet material (surface material) in a paper diaper and a sanitary napkin, lightness, strength, improvement in dry feeling, excellent texture, and the like are required. And as such a sheet material, from the pursuit of dry feeling, a film such as an apertured film, a nonwoven fabric such as a thermal bond nonwoven fabric, a nonwoven fabric in which the fineness of the constituent fibers is increased to increase the capillary diameter and the liquid residue is reduced (for example, patents) Document 1) has been proposed.

  However, the sheet material formed of a film has a problem in that the film does not have a capillary structure, so that no liquid residue is generated, but the feeling of use such as a slimy feeling, a dull feeling, and a sticky feeling is inferior. In addition, in the sheet material formed of nonwoven fabric, in practical use, the feeling of use in a dry state (when dry) is good, but the feeling in use in a wet state (when wet) and after use There was a problem that the appearance of the was inferior. Moreover, in order to improve the dry feeling of the surface of the sheet material formed using the nonwoven fabric, the nonwoven fabric in which the fineness of the constituent fibers is increased to increase the capillary diameter and the remaining liquid is reduced, such as menstrual blood was absorbed. Since the body fluid can be seen through, the visual impression is poor, and the texture characteristic of the nonwoven fabric is impaired.

Especially in recent years, yellow coloring due to infant excrement and urine and red coloring due to menstrual blood have a great influence on the feeling of use, and these coloring is difficult to see. Sheets in disposable diapers and sanitary napkins A material (surface material) is required.
As a method for improving the permeation resistance and concealment of the sheet material, a method for increasing the whiteness by increasing the content of TiO _{2 in} the constituent fibers (Patent Document 2), a method for reducing the fineness of the constituent fibers, and a sheet. A method for increasing the weight of the material has been proposed.

However, if the content of TiO _{2 in} the constituent fibers is too large, there is a problem that not only the fiber spinnability, the processability to the nonwoven fabric, the cut property, etc., but also the cost is increased. Further, when the fineness of the constituent fibers is reduced, not only the productivity of the nonwoven fabric is lowered, but also the liquid permeation rate as a sheet material (surface material) is reduced and the liquid bleeding is increased. There was a problem. In addition, the method of increasing the fabric weight of the nonwoven fabric has problems such as lightness, cost, and remaining liquid.
In addition, lightness, tensile strength and permeation are usually contradictory properties. When the sheet material is reduced in weight, the tensile strength and permeation resistance are impaired, and the tensile strength and permeation resistance of the sheet material are improved. For this reason, when the basis weight of the sheet material is increased, there is a problem that the lightness is impaired.

JP-A-57-205506 JP-A 61-45753

  The present invention is a non-woven fabric containing a main fiber and a binder component, and has an excellent tensile strength and permeation resistance despite having a small basis weight, and a sheet material for absorbent articles using the non-woven fabric. It is to provide.

  As a result of intensive studies to achieve the above problems, the present inventor has a small basis weight by using a fiber having a specific single fiber cross-sectional shape as the main fiber when the nonwoven fabric is composed of the main fiber and the binder component. Nevertheless, the present inventors have found that a non-woven fabric having excellent tensile strength and permeation resistance can be obtained, and have further intensively studied to complete the present invention.

Thus, according to the present invention, “a non-woven fabric containing a main fiber and a binder component and having a basis weight of 48 g / m ² or less, and the single fiber cross-sectional shape of the main fiber is defined by the following formula: A nonwoven fabric characterized by having 12 to 20 openings having an opening angle of not more than 2.0 and less than 120 degrees. "
Flatness = A / B
A: The longest length in the fiber cross section B: The length in the direction perpendicular to the length direction of A in the fiber cross section
At that time, the main fiber is preferably a hollow fiber. Moreover, in the single fiber cross-sectional shape of the said main fiber, it is preferable that the fiber filling rate defined by a following formula is in the range of 30 to 80%.
Fiber filling rate (%) = (C / D) × 100
C: area of the fiber cross section D: circumscribed circle area of the fiber cross section

The single fiber fineness of the main fiber is preferably in the range of 0.5 to 10 dtex. The fiber length of the main fiber is preferably in the range of 3 to 100 mm. Moreover, it is preferable that the said binder component is a core-sheath-type binder fiber. The binder component is preferably a non-fiber resin binder.
Moreover, according to this invention, the sheet | seat material for absorbent articles which uses the said nonwoven fabric is provided.

  According to the present invention, a nonwoven fabric containing main fibers and a binder component, which has excellent tensile strength and permeability even though the basis weight is small, and an absorbent article sheet using the nonwoven fabric Material is provided.

It is a schematic diagram for demonstrating an opening part.

First, in the single fiber cross-sectional shape of the main fiber contained in the nonwoven fabric of the present invention, the flatness of the single fiber cross section (hereinafter sometimes simply referred to as “flatness”) is 2.0 or less (preferably 1 to 1). 1.2) is essential. When the flatness is larger than 2.0, voids are hardly formed between the fibers, so that the fluidity of the binder component is lowered and the fixing point due to the binder component is hardly formed, and a nonwoven fabric having excellent tensile strength is obtained. There is a risk of not. Furthermore, when the flatness is larger than 2.0, the dispersibility of the fibers is lowered, whereby the bulkiness of the nonwoven fabric is lowered, and the soft texture may be impaired. However, the flatness is defined by the following formula.
Flatness = A / B
A: The longest length in the fiber cross section B: The length in the direction perpendicular to the length direction of A in the fiber cross section

  Further, the single fiber cross-sectional shape of the main fiber has two or more openings having an opening angle of less than 120 degrees (preferably 5 or more, more preferably 5 to 25, and further preferably 12 to 20). It is important to have. When the number of the openings is less than 2, the fluidity of the binder component is lowered, and the fixing point due to the binder component is hardly formed, and a nonwoven fabric having an excellent tensile strength may not be obtained. Furthermore, when the number of the openings is less than 2, the dispersibility of the fibers is lowered, whereby the bulk of the nonwoven fabric is lowered, and the soft texture may be impaired. However, the opening part as used in the field of this invention is a location shown in FIG.

In particular, in the single fiber cross-sectional shape of the main fiber, when the fiber filling rate defined by the following formula is within the range of 30 to 80%, the fluidity of the binder component is improved and the fixing point due to the binder component is easily formed. preferable.
Fiber filling rate (%) = (C / D) × 100
C: area of the fiber cross section D: circumscribed circle area of the fiber cross section

  Specific examples of the single fiber cross-sectional shape include a ten cross section, an H cross section, a T cross section, a Y cross section, and an atypical multi-fin cross section. Especially, the hollow fiber which has a hollow part in single fiber cross-sectional shape is preferable. In particular, an atypical multi-fin cross-section having a hollow portion in a single fiber cross-sectional shape is preferable because the fluidity of the binder component is improved and a fixing point due to the binder component is easily formed.

  In the main fiber, the single fiber fineness is preferably in the range of 0.5 to 10 dtex (more preferably 2 to 9 dtex). When the single fiber fineness is less than 0.5 dtex, the process stability and the fiber opening property in the card and airlaid processes may be impaired. On the contrary, if the single fiber fineness is larger than 10 dtex, the tactile feeling of the nonwoven fabric is impaired.

  In the main fiber, the fiber may be long fiber, but short fiber is preferable in order to improve the fluidity of the binder component by increasing the dispersibility of the fiber and to easily form the fixing point by the binder component. At that time, the fiber length is preferably in the range of 3 to 100 mm. When the web is formed by a card process, if the fiber length is less than 3 mm, card process properties such as a fiber opening process may become difficult. On the contrary, if the fiber length is longer than 100 mm, a nonwoven fabric having a uniform texture may not be obtained. Moreover, when forming a web by an airlaid process, it is preferable that this fiber length is 3-25 mm (more preferably 3-10 mm).

  In addition, it is preferable that crimping is imparted to the main fiber because the fluidity of the binder component is improved and a fixing point due to the binder component is easily formed. At that time, as a method for imparting crimps, a spiral crimp is applied using a composite fiber obtained by laminating polymers having different heat shrinkage rates to a side-by-side type, or a spiral crimp is applied by anisotropic cooling, Alternatively, various methods such as imparting mechanical crimping by an ordinary indentation crimper method such that the number of crimps is 3 to 40 pieces / 2.54 cm (preferably 7 to 15 pieces / 2.54 cm) may be used. However, it is optimal to impart mechanical crimping from the viewpoints of bulkiness and manufacturing cost.

  The type of polymer that forms the main fiber is not particularly limited, and may be a normal fiber-forming polymer such as polyester, polyamide, or polyolefin. Of these, polyesters such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polylactic acid, and stereocomplex polylactic acid, and copolyesters obtained by copolymerizing the third component are preferred. Examples of such polyester include material-recycled or chemical-recycled polyester, and polyethylene terephthalate using a monomer component obtained by using biomass, that is, a biological material as a raw material, described in JP-A-2009-091694. May be. Furthermore, the polyester obtained using the catalyst containing the specific phosphorus compound and titanium compound which are described in Unexamined-Japanese-Patent No. 2004-270097 and 2004-2111268 may be sufficient. In the polymer, a fine pore forming agent, a cationic dye dyeing agent, an anti-coloring agent, a heat stabilizer, a fluorescent whitening agent, a matting agent, a coloring agent may be added as necessary within the range not impairing the object of the present invention. 1 type, or 2 or more types of an agent, a hygroscopic agent, and inorganic fine particles may be contained.

  Further, in the main fiber, one or more selected from the group consisting of silicone resin, oil agent, antibacterial agent, insect repellent, water repellent agent, hygroscopic agent, antistatic agent, flame retardant, negative ion generator and deodorant. It is preferable that these agents adhere to the fiber surface because these agents do not easily fall off, and the functions of these agents can be expressed with good durability. The oil agent includes a smoothing agent such as fatty acid ester, polyhydric alcohol ester, ether ester, polyether, silicone, mineral oil, antistatic agent, surfactant, bundling agent, rust inhibitor, preservative, and antioxidant. An agent may be added.

  In the nonwoven fabric of the present invention, the main fiber is fixed by a binder component. In that case, as a binder component, a binder fiber may be sufficient and a non-fiber-type resin binder (for example, powdery chemical binder) may be sufficient. Of these, a core-sheath binder fiber is preferable in obtaining a strong fixing point.

As such a sheath-core type binder fiber, a polymer having a melting point lower by 40 ° C. or more than the polymer forming the main fiber is arranged on the surface as a heat fusion component.
Here, examples of the polymer arranged as the heat fusion component include polyurethane elastomers, polyester elastomers, inelastic polyester polymers and copolymers thereof, polyolefin polymers and copolymers thereof, polyvinyl alcohol polymers, and the like. be able to.

  Among these, polyurethane elastomers include low melting point polyols having a molecular weight of about 500 to 6,000, such as dihydroxy polyether, dihydroxy polyester, dihydroxy polycarbonate, dihydroxy polyester amide, and the like, and organic diisocyanates having a molecular weight of 500 or less, such as p, p. '-Diphenyl methane diisocyanate, tolylene diisocyanate, isophorone diisocyanate hydrogenated diphenyl methane isocyanate, xylylene isocyanate, 2,6-diisocyanate methyl caproate, hexamethylene diisocyanate and the like, and chain extenders having a molecular weight of 500 or less, such as glycol It is a polymer obtained by reaction with amino alcohol or triol.

  Among these polymers, particularly preferred is a polyurethane using polytetramethylene glycol, poly-ε-caprolactam or polybutylene adipate as a polyol. Examples of the organic diisocyanate in this case include p, p'-bishydroxyethoxybenzene and 1,4-butanediol.

  Polyester elastomers include polyether ester copolymers obtained by copolymerizing thermoplastic polyester as a hard segment and poly (alkylene oxide) glycol as a soft segment, and more specifically, terephthalic acid, isophthalic acid, phthalate. Alicyclic dicarboxylic acids such as acid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, diphenyl-4,4′-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, oxalic acid , At least one dicarboxylic acid selected from aliphatic dicarboxylic acids such as adipic acid, sebacic acid, dodecanedioic acid and dimer acid, or ester-forming derivatives thereof, 1,4-butanediol, ethylene glycol trimethylene glycol , Tetramethylene glycol Aliphatic diols such as pentamethylene glycol, hexamethylene glycol neopentyl glycol, decamethylene glycol, or alicyclic diols such as 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane methanol, or the like At least one diol component selected from ester-forming derivatives and the like, and polyethylene glycol, poly (1,2- and 1,3-polypropylene oxide) glycol, poly (tetra Methylene oxide) glycol, a copolymer of ethylene oxide and propylene oxide, a copolymer of ethylene oxide and tetrahydrofuran, and the like. It can be mentioned terpolymer.

  In particular, from the viewpoint of adhesiveness, temperature characteristics, and strength, block copolymer polyether esters having polybutylene terephthalate as a hard component and polyoxybutylene glycol as a soft segment are preferable. In this case, the polyester portion constituting the hard segment is polybutylene terephthalate in which the main acid component is terephthalic acid and the main diol component is a butylene glycol component. Of course, a part of this acid component (usually 30 mol% or less) may be substituted with another dicarboxylic acid component or an oxycarboxylic acid component, and similarly a part of the glycol component (usually 30 mol% or less). May be substituted with a dioxy component other than the butylene glycol component. Further, the polyether portion constituting the soft segment may be a polyether substituted with a dioxy component other than butylene glycol.

  Copolyester polymers include aliphatic dicarboxylic acids such as adipic acid and sebacic acid, aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and naphthalenedicarboxylic acid and / or fats such as hexahydroterephthalic acid and hexahydroisophthalic acid. A co-polymer containing a predetermined number of cyclic dicarboxylic acids and aliphatic or alicyclic diols such as diethylene glycol, polyethylene glycol, propylene glycol, and paraxylene glycol, with addition of oxyacids such as parahydroxybenzoic acid as desired. Polymerized esters and the like can be mentioned. For example, polyesters obtained by adding and copolymerizing isophthalic acid and 1,6-hexanediol in terephthalic acid and ethylene glycol can be used.

Examples of the polyolefin-based polymer include low-density polyethylene, high-density polyethylene, polypropylene, and modified products thereof.
In the core-sheath binder fiber, the above-mentioned polyester is preferably exemplified as the counterpart component of the heat-sealing component. In that case, it is preferable that the heat fusion component occupies at least a half of the surface area. The weight ratio is suitably in the range of 30/70 to 70/30 in terms of the composite ratio of the heat fusion component and the polyester. Although it does not specifically limit as a form of a core-sheath-type binder fiber, It is preferable that a heat-fusion component and polyester are core-sheath types. In this core-sheath-type binder fiber, polyester serves as a core part and the heat fusion component serves as a sheath part, but this core part may be concentric or eccentric. From the viewpoint of adhesiveness to the main fiber and processability (dispersibility, etc.) in the papermaking process, it is more preferable to dispose polyester in the core and dispose low-melting polyester in the sheath.

In the above-mentioned polymer, various stabilizers, ultraviolet absorbers, thickening and branching agents, matting agents, colorants and various other improving agents may be blended as necessary.
In the core-sheath binder fiber, the single fiber fineness is preferably in the range of 1 to 10 dtex (more preferably 1 to 8 dtex). If the single fiber fineness is less than 1 dtex, there is a risk of deteriorating process stability and fiber opening in the card and airlaid processes. On the contrary, if the single fiber fineness is larger than 10 dtex, the touch of the nonwoven fabric may be impaired.

  In the binder fiber, the fiber length is preferably in the range of 3 to 100 mm. When the web is formed by a card process, if the fiber length is less than 3 mm, card process properties such as a fiber opening process may become difficult. On the contrary, if the fiber length is longer than 100 mm, a nonwoven fabric having a uniform texture may not be obtained. Moreover, when forming a web by an airlaid process, it is preferable that this fiber length is 3-25 mm (more preferably 3-10 mm).

  Moreover, it is preferable that crimp is provided in the binder fiber. At that time, as a method for imparting crimps, a spiral crimp is applied using a composite fiber obtained by laminating polymers having different heat shrinkage rates to a side-by-side type, or a spiral crimp is applied by anisotropic cooling, Alternatively, various methods such as imparting mechanical crimping by an ordinary indentation crimper method such that the number of crimps is 3 to 40 pieces / 2.54 cm (preferably 7 to 15 pieces / 2.54 cm) may be used. However, it is optimal to impart mechanical crimping from the viewpoints of bulkiness and manufacturing cost.

  In the nonwoven fabric of the present invention, the main fiber is fixed by a binder component. Here, the main fiber is preferably contained in an amount of 30% by weight or more (more preferably 45 to 75% by weight) relative to the weight of the nonwoven fabric. When the content of the main fiber is less than 30% by weight, the fluidity of the binder component is lowered, and it is difficult to form a fixing point due to the binder component. At that time, when other fibers are included in the nonwoven fabric, the other fibers include natural fibers such as cotton, semi-synthetic fibers such as rayon, and synthetic fibers such as polyester fibers having other cross-sectional shapes. The passage is good and preferable.

  The nonwoven fabric of this invention can be manufactured with the following manufacturing methods, for example. That is, as described above, after blending the main fiber and binder fiber (or non-fiber resin binder) and spinning as a uniform web with a roller card, or after forming a web by the airlaid method, it is necessary. The main fibers are fixed by the binder component by applying heat treatment after lamination (air-through method). At that time, after forming a web by a chemical bond method, a liquid or foam binder resin may be sprayed. Alternatively, the web may be heat-treated while being folded into an accordion shape to form a fixing point by heat fusion, thereby forming a fiber structure in which the constituent fibers are arranged in the thickness direction of the fiber structure.

In the nonwoven fabric thus obtained, it is important that the basis weight is 48 g / m ² or less (more preferably 10 to 48 g / m ² , particularly preferably ²⁰ to 48 g / m ² ). If the basis weight is larger than 48 g / m ² , the lightness may be impaired. On the other hand, if the basis weight is less than 10 g / m ² , a uniform texture may not be obtained when the web is formed by the card method or the web method.

The density of the nonwoven fabric is preferably 0.02 g / cm ³ or less (more preferably 0.005 to 0.02 g / cm ³ ) in order to obtain a soft texture. Further, the thickness of the nonwoven fabric is preferably in the range of 1 to 10 mm (more preferably 2 to 8 mm) in order to achieve both lightness, excellent tensile strength, and permeation resistance.
The nonwoven fabric may be added with known functional processing such as water repellent processing, flameproof processing, flame retardant processing, and negative ion generation processing.

  Such a nonwoven fabric contains main fibers having a single fiber cross-sectional shape as described above, so that the fluidity of the binder component is improved and the fixing points due to the binder component are easily formed, although the basis weight is small. , Has excellent tensile strength. At the same time, light rays are confined between the main fibers having the single fiber cross-sectional shape as described above, and the permeation resistance is improved.

Next, the absorbent article sheet material of the present invention is an absorbent article sheet material using the above-mentioned nonwoven fabric.
As an absorbent article to which such a sheet material is applied as a surface material or an intermediate material, sanitary materials such as paper diapers and sanitary napkins are suitable, but desiccants, hygroscopic agents, towels, and wall materials for absorbing moisture. A water-absorbing article such as
Since this nonwoven fabric is used for such a sheet material for absorbent articles, it has excellent tensile strength and permeability even though the basis weight is small.

  Next, although the Example and comparative example of this invention are explained in full detail, this invention is not limited by these. In addition, each measurement item in an Example was measured with the following method.

(1) Melting point Using a differential thermal analyzer 990 manufactured by Du Pont, measured at a temperature increase of 20 ° C./min, and obtained a melting peak. If the melting temperature is not clearly observed, the melting point is the temperature at which the polymer softens and starts to flow (softening point) using a trace melting point measuring device (manufactured by Yanagimoto Seisakusho). In addition, the average value was calculated | required by n number 5.

(2) Number of crimps The number of crimps was measured by the method described in JIS L 1015 7.12. In addition, the average value was calculated | required by n number 5.

(3) Flatness After 20 main fibers were extracted and observed by SEM, the average value was calculated by the following formula.
Flatness = A / B
A: The longest length in the fiber cross section B: The length in the direction perpendicular to the length direction of A in the fiber cross section

(4) Fiber filling rate (%) = (C / D) × 100
C: area of the fiber cross section D: circumscribed circle area of the fiber cross section

(5) Hardness (elasticity)
It was measured by 25% compression hardness according to JIS-K6400.

(6) Repeated compression residual strain (durability)
It was measured by the method described in JIS-K6400. If it is 6.5% or less, it is considered good.

(7) Thickness, basis weight, density Measured according to JIS K6400.

(8) Number of openings having an opening angle of less than 120 degrees After one main fiber was extracted and subjected to SEM observation, the number of openings having an opening angle of less than 120 degrees was counted.

(9) Strength ratio Measured in tensile mode using a tensile / compression tester. First, the nonwoven fabric is cut into a size of 100 mm × 25 mm, and a test piece is collected. The initial specimen length (distance between chucks) is set to 50 mm between the air chucks mounted on the tensile / compression tester, and the chuck attached to the load cell (rated output 5 kg) of the tensile / compression tester is 200 mm / The test piece is stretched at a rate of minutes. By this series of operations, the maximum strength K1 (N) in the longitudinal direction (MD) of the nonwoven fabric was measured.
On the other hand, a solid round cross-section fiber of the same fineness was used as the main fiber, and the nonwoven fabric was made into the nonwoven fabric by the same conditions and the same manufacturing method, and the maximum strength of the nonwoven fabric was set to K0.
And the strength ratio of the nonwoven fabric from which the cross-sectional shape of other main fibers differs was computed with the following formula.
Intensity ratio = K1 / K0
K0: K value of a non-woven fabric produced by the same conditions and the same manufacturing method with a solid round cross-section fiber of the same fineness as the main fiber, K1: K value of the non-woven fabric

(10) Permeability The L value of the nonwoven fabric was measured using a Machbeth Color-Eye 3100 (manufactured) with a light source D65 and a 10-degree field of view. A solid round cross-section fiber of the same fineness was used as a main fiber, and a non-woven fabric was produced using the same conditions and the same manufacturing method as the standard. The L value of the nonwoven fabric was defined as L0. And the permeation-proof property of the nonwoven fabric which changed the cross-sectional shape of the main fiber was computed with the following formula.
Permeability = (L1-LR) / (L0-LR)
L0: L value of a non-woven fabric prepared by the same conditions and the same manufacturing method with a solid round cross-section fiber of the same fineness when a red reference cloth (L value is 34) is overlapped on the back, L1: Red reference L value LR of nonwoven fabric when cloth (L value is 34) is overlapped on the back: L value 34 of red reference cloth

[ Reference Example 1 ]
Using a polytrimethylene terephthalate having an intrinsic viscosity of 0.85 and a melting point of 225 ° C., changing the die appropriately, melt spinning, and drawing, the single fiber fineness having a single fiber cross-sectional shape as shown in Table 1 A main fiber of 6.6 dtex (fiber length 51 mm, number of crimps 9 / 2.54 cm) was obtained.
On the other hand, core sheath type binder fiber (single fiber fineness 6.6 dtex, fiber length 51 mm, crimp number 9 / 2.54 cm, single fiber cross-sectional shape: round cross section) manufactured by Teijin Fibers Ltd. was prepared. This core-sheath binder fiber is a copolymer polyester having a melting point of 110 ° C. (an acid component obtained by mixing terephthalic acid and isophthalic acid at 60/40 (mol%), ethylene glycol and diethylene glycol 85/15 ( A diol component mixed at a mol%)) is disposed in the sheath component, and polyethylene terephthalate is disposed in the core component.
Next, after blending the main fiber and the core-sheath binder fiber at a blend ratio of (main fiber / core-sheath binder fiber) 30/70, a uniform web was obtained using a roller card. The web was weighed and subjected to heat treatment using a hot air circulation dryer (180 ° C. × 1 minute) to obtain a nonwoven fabric. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.
Next, when a diaper (absorbent article) was obtained using the nonwoven fabric as a skin material, the diaper had excellent tensile strength and permeability even though the basis weight was small.

[ Reference Example 2 ]
The same procedure as in Reference Example 1 was performed except that the atypical die used in Reference Example 1 was changed and the cross-sectional shape of the main fiber was changed. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[ Reference Example 3 ]
The same procedure as in Reference Example 1 was performed except that the atypical die used in Reference Example 1 was changed and the cross-sectional shape of the main fiber was changed. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[ Reference Example 4 ]
The same procedure as in Reference Example 1 was performed except that the atypical die used in Reference Example 1 was changed and the cross-sectional shape of the main fiber was changed. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[ Reference Example 5 ]
The same procedure as in Reference Example 1 was performed except that the atypical die used in Reference Example 1 was changed and the cross-sectional shape of the main fiber was changed. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[Example 1 ]
The same procedure as in Reference Example 1 was performed except that the atypical die used in Reference Example 1 was changed and the cross-sectional shape of the main fiber was changed. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[ Reference Example 6 ]
The main fiber used in Reference Example 1 and the core-sheath type binder fiber used in Reference Example 1 are blended at a ratio of (main fiber / core-sheath type binder fiber) 30/70, and a uniform web is formed using airlaid equipment. Obtained. This web was heat-treated using a hot air circulation dryer (180 ° C. × 1 minute) to obtain a nonwoven fabric. Table 1 shows the main fibers used, and Table 3 shows the physical properties of the obtained nonwoven fabric.

[Example 2 ]
The same procedure as in Reference Example 6 was performed except that the atypical die used in Reference Example 6 was changed and the cross-sectional shape of the main fiber was changed. Table 1 shows the main fibers used, and Table 3 shows the physical properties of the obtained nonwoven fabric.

[Comparative Example 1]
The same procedure as in Reference Example 1 was performed except that the atypical die used in Reference Example 1 was changed and the cross-sectional shape of the main fiber was changed. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[Comparative Example 2]
The same procedure as in Reference Example 1 was performed except that the atypical die used in Reference Example 1 was changed and the cross-sectional shape of the main fiber was changed. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[Comparative Example 3]
The atypical die used in Reference Example 1 is changed, and the cross-sectional shape of the main fiber is the same as that described in Reference Example 1 of Japanese Patent Application Laid-Open No. 2004-162194. The procedure was the same as in Reference Example 1 except that Table 2 shows the physical properties of the obtained nonwoven fabric.

[Comparative Example 4]
A nonwoven fabric was obtained under the same conditions as in Reference Example 1 except that the main fiber was changed to a solid round cross section. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[Comparative Example 5]
A nonwoven fabric was obtained under the same conditions as in Reference Example 1 except that the main fiber was changed to a hollow round cross section. Table 1 shows the main fibers used, and Table 2 shows the physical properties of the obtained nonwoven fabric.

[Comparative Example 6]
A nonwoven fabric was obtained under the same conditions as in Reference Example 6 except that the main fiber was changed to a solid round cross section. Table 1 shows the main fibers used, and Table 3 shows the physical properties of the obtained nonwoven fabric.

  According to the present invention, a nonwoven fabric containing main fibers and a binder component, which has excellent tensile strength and permeability even though the basis weight is small, and an absorbent article sheet using the nonwoven fabric A material is obtained, and its industrial value is extremely large.

  1 to 16: opening having an opening angle of less than 120 degrees

Claims (8)

A nonwoven fabric containing a main fiber and a binder component and having a basis weight of 48 g / m ² or less,
The main fiber has a single fiber cross-sectional shape having a flatness of 2.0 or less in cross section defined by the following formula and having 12 to 20 openings having an opening angle of less than 120 degrees. Non-woven fabric.
Flatness = A / B
A: The longest length in the fiber cross section B: The length in the direction perpendicular to the length direction of A in the fiber cross section The nonwoven fabric according to claim 1, wherein the main fiber is a hollow fiber. The nonwoven fabric according to claim 1 or 2, wherein a fiber filling rate defined by the following formula is within a range of 30 to 80% in a single fiber cross-sectional shape of the main fiber.
Fiber filling rate (%) = (C / D) × 100
C: Area of fiber cross section
D: circumscribed circle area of the fiber cross section The nonwoven fabric in any one of Claims 1-3 whose single fiber fineness of the said main fiber exists in the range of 0.5-10 dtex. The nonwoven fabric according to any one of claims 1 to 4, wherein a fiber length of the main fiber is in a range of 3 to 100 mm. The nonwoven fabric in any one of Claims 1-5 whose said binder component is a core-sheath-type binder fiber. The nonwoven fabric in any one of Claims 1-5 whose said binder component is a non-fiber-type resin binder. The sheet | seat material for absorbent articles which uses the nonwoven fabric described in any one of Claims 1-7.