JP2021132701A - Nonwoven fabric for absorbent article and absorbent article - Google Patents

Abstract

To provide a nonwoven fabric for an absorbent article which is excellent in recoverability of a thickness against compression and has a good cushion property, and an absorbent article equipped with the same.SOLUTION: A nonwoven fabric for an absorbent article in the invention comprises an air-through nonwoven fabric. The nonwoven fabric for an absorbent article is constituted of a non-stretchable fiber, and the non-stretchable fiber includes a fine fiber with a fiber diameter of 15 μm or smaller. In the nonwoven fabric for an absorbent article, a ratio of the fine fiber is 30% or higher relative to the entire constituent fibers. The nonwoven fabric for an absorbent article has a basis weight of 30 g/m2 or less, has both flat surfaces, and has a thickness of 1.6 mm or more after applying a load of 30 cN/cm2 for 24 hours. The non-stretchable fiber preferably contains one or more kinds of resin components selected from a group of polyethylene, polypropylene, and polyethylene terephthalate.SELECTED DRAWING: None

Description

The present invention relates to a non-woven fabric for an absorbent article and an absorbent article comprising the same.

Absorbent articles such as disposable diapers are generally distributed in compressed packaging. From the viewpoint of obtaining softness and cushioning feeling after being opened from the package form, it is desired that the bulk of the absorbent article is restored. Therefore, as a non-woven fabric used for an absorbent article, a non-woven fabric having excellent bulkiness and bulk recovery property has been studied. For example, Patent Document 1 describes a non-woven fabric having a predetermined core component and sheath component and made of an eccentric core-sheath composite fiber web that is spirally crimped, and the fibers are heat-bonded to each other. A sheet having excellent bulk recovery is disclosed in which the specific volume and the thickness recovery rate immediately after compression for 24 hours are each within a predetermined range.

Further, the applicant is composed of a fiber aggregate containing a predetermined amount of an elastomer component or a fiber aggregate in which a large number of regularly arranged convex portions are formed, and has a basis weight of 15 to 100 g / m. ^{No. 2} , a compression recovery sheet having a no-load thickness of 1 to 10 mm and a compression recovery rate of 60% or more has been proposed (Patent Documents 2 and 3).

Japanese Unexamined Patent Publication No. 8-92851 Japanese Unexamined Patent Publication No. 2001-20167 Japanese Unexamined Patent Publication No. 2001-20168

The air-through non-woven fabric produced by blowing hot air such as air or water vapor onto the fiber web has a fluffy cushioning feeling immediately after production. However, when the air-through non-woven fabric is used as a constituent member of the absorbent article, when it is sealed in the above-mentioned packaging form, it tends to be difficult to generate the original cushioning feeling by compression. Although the recoverability of the thickness (bulk) of each of the sheets described in Patent Documents 1 to 3 is taken into consideration, there is room for further improvement in the recoverability of the thickness.

An object of the present invention is to provide a non-woven fabric for an absorbent article having excellent thickness recovery with respect to compression and good cushioning property, and an absorbent article having the same.

The present invention is a non-woven fabric for absorbent articles made of an air-through non-woven fabric.
It is composed of non-stretchable fibers, and the non-stretchable fibers contain fine fibers having a fiber diameter of 15 μm or less.
The ratio of the fine fibers to all the constituent fibers is 30% or more.
Provided is a non-woven fabric for absorbent articles having a basis weight of 30 g / m ² or less, flat surfaces on both sides, and a thickness of 1.6 mm or more after applying a load of ^{30 cN / cm 2 for 24 hours.}

The present invention also provides an absorbent article comprising the non-woven fabric for the absorbent article as a constituent member.

According to the present invention, there is provided a non-woven fabric for an absorbent article having excellent thickness recovery with respect to compression and good cushioning property, and an absorbent article having the same.

Hereinafter, the present invention will be described based on the preferred embodiment with reference to the drawings.
The non-woven fabric for absorbent articles of the present embodiment (hereinafter, also simply referred to as “nonwoven fabric”) is an air-through non-woven fabric. The "air-through non-woven fabric" refers to a non-woven fabric produced through a step (air-through step) of spraying a fluid having a temperature equal to or higher than a predetermined temperature, for example, gas or water vapor, onto a fiber web or a non-woven fabric which is a precursor of the non-woven fabric. The spraying of such a fluid is performed by a so-called air-through method (penetration method) in which a fluid such as hot air penetrates the fiber web or the non-woven fabric. The air-through non-woven fabric of the present invention includes not only the non-woven fabric produced only by the heat treatment step by the air-through method, but also the non-woven fabric manufactured by adding the heat treatment step to the non-woven fabric produced by another method, or after the air-through step. Nonwoven fabrics manufactured by performing some process are included.

The non-woven fabric of the present embodiment has a plurality of heat-sealed portions in which the intersections of the constituent fibers are heat-sealed. Such a heat-sealed portion is formed in a portion where the constituent fibers are in contact with each other, and is three-dimensionally dispersed and arranged in the non-woven fabric.

The non-woven fabric of the present embodiment has two surfaces separated in the thickness direction along a direction orthogonal to the thickness direction of the non-woven fabric. When the nonwoven fabric of the present embodiment is used as a constituent member of the absorbent article, the surface of the nonwoven fabric is usually a surface of the absorbent article that faces the skin of the wearer (skin facing surface) or that of the wearer. It is a surface facing the opposite side of the skin (non-skin facing surface) or a surface facing clothing such as shorts (clothing facing surface).

The non-woven fabric of the present embodiment is made of non-stretchable fibers. Non-stretchable fibers are fibers composed of non-elastic constituents. "Non-stretchable fibers" are "stretchable" and when released from a state where they are stretched 50% of their original length (which is 150% of their original length). It means a fiber that does not have the property of returning to a length of 3% or less of the length of the fiber.
From the viewpoint of forming the heat-sealed portion described above, the nonwoven fabric of the present embodiment preferably contains thermoplastic fibers as non-stretchable fibers. That is, the non-woven fabric of the present embodiment preferably contains non-stretchable and thermoplastic fibers. Examples of such fibers include polyolefins such as polyethylene (PE) and polypropylene (PP); polyesters such as polyethylene terephthalate (PET); polyamides such as nylon 6 and nylon 66; polyacrylic acid, polymethacrylic acid alkyl esters, and poly. Examples thereof include fibers made of a thermoplastic resin such as vinyl chloride and polyvinylidene chloride, and one of these fibers can be used alone or in combination of two or more.

The non-stretchable and thermoplastic fiber used for the non-woven fabric of the present embodiment may be a single fiber made of one kind of synthetic resin or a blend polymer obtained by mixing two or more kinds of synthetic resins, or may be a composite fiber. The composite fiber referred to here is a synthetic fiber obtained by combining two or more kinds of synthetic resins having different components with a spinneret and spinning them at the same time, and has a structure in which a plurality of components are continuous in the length direction of the fiber. Those that are mutually bonded in the fiber. Examples of the form of the composite fiber include a core-sheath type having a core-sheath structure composed of a core portion and a sheath portion, a side-by-side type, and the like.

From the viewpoint of production cost, the non-stretchable and thermoplastic fiber preferably contains one or more resin components selected from the group consisting of PE, PP, and PET.
The non-stretchable fiber preferably contains PE as a constituent resin, more preferably contains PE at least on the surface, and further preferably consists of PE.
For example, when a fiber having a core-sheath structure is included as a non-stretchable fiber, the resin component of the core portion (hereinafter, also referred to as “core component”) is PET, and the resin component of the sheath portion (hereinafter, “sheath component””. Also referred to as) is preferably polyethylene.

A preferable example of the non-stretchable and thermoplastic fiber is a thermoplastic fiber composed of a core-sheath type composite fiber, in which the core component is one or more selected from the group consisting of PET and PP, and the sheath component is PE. There is one that is.

The non-woven fabric of the present embodiment may contain other non-stretchable fibers in addition to the non-stretchable and thermoplastic fibers. Examples of such other non-stretchable fibers include natural fibers such as pulp and cotton, cellulosic fibers such as rayon, lyocell and tencel, and one of these fibers alone or in combination of two or more. Can be used.
In particular, when the non-woven fabric contains a core-sheath type composite fiber in which the core component is PET and the sheath component is PE, it is preferable to use cotton mixed.

From the viewpoint of forming the heat-sealed portion described above, the ratio of the other non-stretchable fibers to the total constituent fibers is preferably 95% by mass or more, more preferably 99% by mass or more, and preferably 100% by mass. It is as follows.

The above-mentioned non-stretchable fiber is a fiber made of a non-elastic resin, and a fiber having properties contradictory to this is a stretchable fiber. Elastic fibers are fibers made of elastic resin. Examples of the constituent resins of such fibers include SBS (styrene-butadiene-styrene), SIS (styrene-isoprene-styrene), SEBS (styrene-ethylene-butadiene-styrene), and SEPS (styrene-ethylene-propylene-styrene). Styrene-based elastomers such as, olefin-based elastomers (ethylene-based α-olefin elastomers, propylene-based elastomers obtained by copolymerizing ethylene, butene, octene, etc.), polyester-based elastomers, polyurethane-based elastomers, and the like can be mentioned. The non-woven fabric of the present embodiment does not contain such elastic fibers.

In the nonwoven fabric of the present embodiment, the non-stretchable fibers include fibers having a fiber diameter of 15 μm or less (hereinafter, also referred to as “fine fibers”). The non-woven fabric of the present embodiment has a ratio of fine fibers to all constituent fibers of 30% or more. Such a ratio is also referred to as a "fine fiber ratio" below. From the viewpoint of improving the flexibility of the non-woven fabric, the fine fiber ratio is preferably 20% or more, more preferably 30% or more, and preferably 100% or less. The fine fiber ratio is a ratio (%) of the mass of the fine fibers to the mass of all the constituent fibers constituting the non-woven fabric, and can be obtained based on the mass of the fibers used when producing the non-woven fabric. In addition, the fine fiber ratio of the non-woven fabric can be determined by the following method of surface observation. If the fine fiber ratio obtained by at least one of the method obtained from the ratio of the amount of fine fibers used (mass) and the method by the following surface observation is 30% or more, the "for all constituent fibers" in the present invention. The condition that the ratio of the fine fibers is 30% or more is satisfied. As will be described later, the non-woven fabric of the present embodiment has a basis weight of 30 g / m ² or less and is a non-woven fabric having flat surfaces on both sides. Therefore, most of the fibers can be observed by the following surface observation. Therefore, the fine fiber ratio may be defined as follows.

With respect to the non-woven fabric to be measured, a region of 10 mm × 10 mm is cut out over the entire thickness direction using a sharp razor, and this is used as a measurement sample. Surface observation is performed on one surface of the measurement sample using a scanning electron microscope (Scanning Electron Microscope: SEM, JCM-6000, trade name, manufactured by JEOL Ltd. All SEMs in the present specification are this). .. At this time, a region (observation region) of 500 μm × 400 μm is photographed at a magnification of 200 times. In this SEM imaging, the fibers located on the outermost surface of the surface to be photographed of the measurement sample are focused. For one measurement sample, 5 points having different positions from each other are photographed to obtain a total of 5 SEM images. Then, in each SEM image, the focused fibers are selected. For each of the focused fibers, select any portion other than the heat-sealed portion and draw a line orthogonal to the longitudinal direction of the fiber at the selected portion. The transfer length of the fibers along the orthogonal lines is measured as the fiber diameter. In such a measurement, in the focused fiber, the transfer line indicating the transfer length, that is, the line orthogonal to the longitudinal direction of the fiber and the line indicating the contour of the fiber are measured at positions orthogonal to each other. The "focused fiber" is a fiber whose contour is not blurred within a region of 500 μm × 400 μm in the SEM image. The number of fibers having a measured fiber diameter of 15 μm or less is counted as the number of fine fibers, and the ratio of the number of the fine fibers to the number of the focused fibers in the SEM image, that is, “number of fine fibers / focusing) Calculate the percentage (%) of "the number of fibers". Such a ratio is obtained for each of a total of five SEM images obtained from the measurement sample, and the average of these is defined as the "single-sided fine fiber ratio". Next, the measurement of the "single-sided fine fiber ratio" is performed for each of both sides of the non-woven fabric, and the average of these is taken as the fine fiber ratio.

The basis weight of the non-woven fabric of this embodiment is 30 g / m ² or less. From the viewpoint of more reliably achieving cushioning properties and suppressing production costs, the basis weight of the non-woven fabric of the present embodiment is preferably 8 g / m ² or more, more preferably 10 g / m ² or more, and preferably 10 g / m 2 or more. It is 28 g / m ² or less, more preferably 26 g / m ² or less.

The non-woven fabric of the present embodiment is flat on both sides. In other words, the non-woven fabric of the present embodiment does not have an uneven shape on both sides. The "concavo-convex shape" includes, for example, a shape in which a plurality of convex portions or concave portions are formed in a plane direction, and a shape in which convex portions and grooves extending in one direction are alternately formed. That is, the non-woven fabric of the present embodiment does not have these protrusions, recesses, ridges, and grooves on both sides.

The non-woven fabric of the present embodiment has a thickness of 1.6 mm or more after applying a load of ^{30 cN / cm 2 for 24 hours.} Such a thickness is also hereinafter referred to as "recovery thickness". From the viewpoint of more reliably achieving the recovery of the thickness described later, the recovery thickness is preferably 1.7 mm or more, more preferably 1.8 mm or more, and preferably 8 mm or less, more preferably 5 mm or less. Regarding the recovery thickness, the " ^{load of 30 cN / cm 2} " is set as a load 1.1 times the load applied to the absorbent article enclosed in the package in a compressed state. The recovery thickness is measured by the following measuring method.

[Measurement method of recovery thickness]
With respect to the non-woven fabric to be measured, a region of 100 mm × 140 mm is cut out over the entire thickness direction using a sharp razor, and this is used as a measurement sample. Next, the measurement sample is sandwiched between two pressure plates having an area larger than the sample and made of an acrylic plate or a PET plate (thickness is within 3 mm), and a weight of 10 kg is placed on the pressure plate to 30 cN. A load of / cm ² is applied to the measurement sample. In this way, after compressing the measurement sample for 24 hours, within 30 seconds after removing the pressure plate and the weight, the thickness of the measurement sample under a load of 0.5 g is measured by the laser thickness gauge ZSLD manufactured by OMRON Corporation. Measure using -80. The above measurement is performed for each measurement sample, and the average of these is taken as the recovery thickness.

The absorbent article is generally distributed in a compressed state inside the package. When the non-woven fabric of the present embodiment is used as a constituent member of an absorbent article, when the package is opened and the compressed state is released, the non-woven fabric has a recovery thickness of 1.6 mm or more, so that the thickness is good. Recover. The recoverability of such thickness is considered to be due to the following reasons. Since both sides of the nonwoven fabric of the present embodiment are flat, the ratio of the fine fibers to all the constituent fibers, and the basis weight of the nonwoven fabric are within the above-mentioned ranges, the flexibility of the entire nonwoven fabric is high, and the constituent fibers are present in the packaging form. Easy to increase the density. Further, since the non-stretchable fibers forming the non-woven fabric are inelastic, they are unlikely to be deformed by compression, so that a repulsive force against compression is likely to act. When such a non-woven fabric is put into an open state in which compression is released from a compressed state, the gap between the constituent fibers returns to a state close to the original due to the repulsive force of the non-stretchable fibers. That is, since the density of the constituent fibers is likely to return to the density before packaging, the thickness of the non-woven fabric is satisfactorily restored, and due to this, good cushioning property can be obtained.

From the viewpoint of further improving the recoverability of the thickness, the average fiber diameter of the constituent fibers in the nonwoven fabric of the present embodiment is preferably 5 μm or more, more preferably 10 μm or more, and preferably 18 μm or less, more preferably 15 μm or less. be.
The non-woven fabric may be composed of a plurality of types of fibers having different fiber diameters, but from the same viewpoint as described above, the non-woven fabric is preferably composed of constituent fibers having a fiber diameter of 20 μm or less, and is composed of constituent fibers having a fiber diameter of 15 μm or less. Is more preferable. When the nonwoven fabric contains a plurality of types of fibers having different fiber diameters, the "average fiber diameter" is the average of the fiber diameters of the constituent fibers in the entire nonwoven fabric.

The fiber diameter of the constituent fibers of the non-woven fabric is determined by the following method. The non-woven fabric is SEM-observed by the same method as the above-mentioned [Measuring method of fine fiber ratio]. Arbitrarily select 10 of the above-mentioned "focused fibers" in the SEM image of this non-woven fabric. Next, the fiber diameter described above is measured for each of these 10 fibers. Next, the arithmetic mean value of the fiber diameter is obtained for the 10 fibers for each of a total of 5 SEM images obtained from the measurement sample. Such an arithmetic mean value is obtained for each of both sides of the non-woven fabric, and the average of these values is taken as the average fiber diameter.

The non-woven fabric of the present embodiment is for an absorbent article and is used as a constituent member of the absorbent article. The term "absorbable article" as used herein broadly includes articles used for absorbing body fluids (urine, loose stool, menstrual blood, sweat, etc.) discharged from the human body, and includes, for example, disposable diapers, sanitary napkins, and sanitary napkins. Includes shorts, incontinence pads, etc.

Absorbent articles typically include a liquid permeable surface sheet located relatively close to the wearer's skin and a liquid permeable or liquid permeable material located relatively far from the wearer's skin. It is provided with a liquid-impermeable or water-repellent back sheet and a liquid-retaining absorber disposed between the two sheets. The absorbent article may include an exterior body that forms its outer surface.
When the non-woven fabric of the present embodiment is used as an absorbent article, the absorbent article includes the non-woven fabric as a constituent member.

The non-woven fabric of the present embodiment is basically composed of a single-layered non-woven fabric obtained by the air-through method, but when used as a constituent member of an absorbent article, other non-woven fabrics, films and the like are used. It may be in a state of being laminated with the sheet material of.

From the viewpoint of further improving the feel and wearing feeling of the absorbent article by the good cushioning property, the absorbent article in which the nonwoven fabric of the present embodiment is used is a sheet forming the outermost surface of the absorbent article. It is preferable to use it for. Specifically, the non-woven fabric of the present embodiment is preferably provided as either one or both of the front surface sheet and the back surface sheet, and more preferably the non-woven fabric is provided as the back surface sheet. From the viewpoint of ensuring leak resistance more reliably, such a back surface sheet is preferably made of a laminated sheet of a liquid impervious sheet and the non-woven fabric.
From the same viewpoint as above, it is preferable that the absorbent article is provided with the non-woven fabric of the present embodiment as an exterior body forming the outer surface of the absorbent article. In particular, since the non-woven fabric of the present embodiment is flat on both sides, a smooth feel can be obtained by using it as an exterior body.

When the non-woven fabric of the present embodiment is incorporated in a product such as a commercially available absorbent article, a cold spray is sprayed on the absorbent article to apply an adhesive for adhering the constituent members of the absorbent article. The non-woven fabric is taken out by solidifying and disassembling each member such as a front sheet, an absorbent sheet, and a back sheet. Unless otherwise specified, this extraction method can be commonly applied to other measurement methods in the present specification.

Next, the method for producing the nonwoven fabric of the above-described embodiment will be described. This manufacturing method includes a heat treatment step of blowing hot air into a fiber web containing thermoplastic fibers by an air-through method. The heat treatment step is a step of forming a non-woven fabric by fusing the intersections of the constituent fibers of the fiber web to form a heat-sealed portion.

The fiber web is typically produced by opening a raw material fiber such as a thermoplastic fiber with a fiber opening machine and converting the opened raw material fiber into a web with a card machine. The fiber web is a sheet-like material before it is formed into a non-woven fabric, and the fibers are not heat-sealed in the fiber web. As the raw material fiber, that is, the constituent fiber of the fiber web, it is preferable to use the same one as the constituent fiber of the non-woven fabric described above. Further, it is preferable that the basis weight of the fiber web is adjusted to the range of the basis weight of the above-mentioned non-woven fabric.
The fiber web may be a laminated web made by laminating a plurality of types of fibers having different fiber diameters or a mixed web made by mixing them.
When three or more laminated webs are used, the layer forming the surface of the laminated web is composed of thermoplastic fibers, and the intermediate layer interposed between the layers forming the surface is a non-thermoplastic material such as cotton. It may be composed of fibers.

A heat treatment step is performed on the obtained fiber web. More specifically, it is placed on, for example, a resin mesh belt, a metal endless net made of wire mesh, a metal plate with vents, or a metal plate without vents. Then, hot air or steam is blown from the fiber web side to heat-fuse the intersections of the fibers. As a result, the obtained non-woven fabric is formed with two surfaces, a surface facing the plate or net (hereinafter, also referred to as a non-sprayed surface) and a surface for which hot air is sprayed (hereinafter, also referred to as a sprayed surface).

The temperature of the hot air in the normal air-through treatment is set in a range about 10 ° C. higher than the lowest melting point of the constituent fibers of the fiber web (for example, the melting point in the sheath portion of the core-sheath type composite fiber), but the non-woven fabric From the viewpoint of facilitating the conversion, the temperature difference between the temperature of the hot air and the melting point of the constituent fibers is preferably 5 ° C. or higher, more preferably 10 ° C. or higher, and preferably 70 ° C. or lower, more preferably 50 ° C. It is as follows.
The lowest melting point of the constituent fibers refers to the melting point of the lowest melting point among the resins when the fibers have a plurality of types of resins such as core-sheath type composite fibers. In the case of a resin that does not have a definite melting point, it refers to the softening point.

From the viewpoint of increasing the thickness of the non-woven fabric and ensuring cushioning, the air velocity of the hot air blown to the fiber web in the heat treatment step is 0.3 m / sec or more, preferably 0.5 m / sec or more, more preferably. Is 0.8 m / sec or more, and 10 m / sec or less, preferably 5 m / sec or less, and more preferably 3 m / sec or less.

In the heat treatment step, the time for blowing hot air onto the fiber web (heat treatment time) may be about the same as that of the conventional air-through non-woven fabric manufacturing method, but from the same viewpoint as above, the heat treatment time is preferably 1 second or more. , More preferably 3 seconds or more, and preferably 60 seconds or less, more preferably 30 seconds or less from the viewpoint of increasing the production speed as much as possible and reducing the production cost.

From the viewpoint of increasing the thickness of the non-woven fabric, it is preferable that the heat treatment step is performed in this manufacturing method with a separate sheet interposed inside the fiber web. With such a configuration, even if hot air is blown to form a non-woven fabric, the bulky state can be easily maintained. As the separate sheet, various sheets containing a fiber material can be used. Examples thereof include papers such as wet papers and dry papers, woven fabrics, non-woven fabrics, knitted fabrics, and composite sheets thereof. From the viewpoint of reducing the cost, it is preferable to use paper or non-woven fabric.
Hereinafter, a separate sheet interposed inside the fiber web, in which the fiber web is made into a non-woven fabric and then removed from the non-woven fabric, is referred to as an "intervening sheet". In a laminated web having three or more layers, a sheet that is not removed from the non-woven fabric after forming an intermediate layer between layers forming the surface of the laminated web and forming a non-woven fabric is not an interwoven sheet.

As a method of arranging the interposition sheet inside the fiber web, a method of forming a laminated web in which the interposition sheet is sandwiched between them, specifically, a method of forming a laminated web in which the interposition sheet is sandwiched between them, specifically, a high melting temperature much higher than the melting temperature of PE such as PET. Examples thereof include a method of sandwiching a fiber sheet having a temperature and a method of mixing fibers having a high melting temperature.

After performing the heat treatment step with the interposition sheet arranged inside the fiber web, the interposition sheet is removed from the obtained non-woven fabric. For example, after heat treatment (air-through treatment) is performed on the laminated web laminated with the interposition sheet sandwiched between them, the interposition sheet is pulled out from the obtained non-woven fabric to remove it.

Although the present invention has been described above based on the preferred embodiment, the present invention is not limited to the above embodiment and can be appropriately modified. Further, each of the above-described configurations may be combined as appropriate.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to such Examples.

[Example 1]
As the raw material fiber, a 1.2 dtex thermoplastic fiber composed of a concentric core-sheath type composite fiber having a core component of PET and a sheath component of PE (core-sheath ratio 50% by mass: 50% by mass) was used. Such raw material fibers had a minimum melting point of 120 ° C. ^Two fiber webs were produced using a known card machine according to a conventional method so that the basis weight was 10 g / m 2. Next, one Kimwipe (registered trademark) (manufactured by Nippon Paper Crecia Co., Ltd., S-200) was sandwiched between two fiber webs as an intervening sheet to prepare a laminated web. With this laminated web placed on a resin mesh belt, a heat treatment step of blowing hot air was performed by an air-through method to form a non-woven fabric, and then Kimwipe was pulled out to produce a non-woven fabric. The heat treatment conditions in the heat treatment step (air-through treatment) are as shown in Table 1.

[Example 2]
A non-woven fabric was produced by the same method as in Example 1 except that a laminated web prepared by sandwiching an intermediate layer between two fiber webs was used. The intermediate layer was a fiber web produced using PET fiber (manufactured by Teijin Frontier Co., Ltd., trade name "Teijin Tetron 3.3dtex") so as to have a basis weight of 2 g / m ^2. In Example 2, the non-woven fabric was produced without pulling out the intermediate layer.

[Example 3]
Using the raw material fibers of Example 1, ^two fiber webs were produced so as to have a basis weight of 12 g / m 2. In the same manner, one fiber web was manufactured using Marusan Sangyo cotton as a raw material fiber so as to have a basis weight of 4 g / m ^2, and a laminated web was manufactured by using this as a middle layer (intermediate layer). A non-woven fabric was produced by the same method as in Example 1 except that the laminated web was used and the heat treatment conditions in the heat treatment step (air-through treatment) were different from those in Example 1. In Example 3, the non-woven fabric was produced without pulling out the intermediate layer.

[Comparative Example 1]
A non-woven fabric was produced by the same method as in Example 1 except that a laminated web was produced without sandwiching an intervening sheet between the two fiber webs.

[Comparative Example 2]
A non-woven fabric was produced by the same method as in Comparative Example 1 except that the basis weight and the heat treatment conditions in the heat treatment step (air-through treatment) were different.

[Comparative Example 3]
A non-woven fabric was produced by the same method as in Comparative Example 2 except that the basis weights were different. The heat treatment conditions in the heat treatment step (air-through treatment) are as shown in Table 1.

[Comparative Example 4]
A non-woven fabric was produced by the same method as in Comparative Example 2 except that the basis weights were different. The heat treatment conditions in the heat treatment step (air-through treatment) are as shown in Table 1.

[Measurement of thickness]
The thickness of the immediately-produced nonwoven fabrics obtained in Examples and Comparative Examples was measured by the method described above. The measurement results are shown in Table 1.

[Measurement of recovery thickness]
The recovery thickness of the non-woven fabrics obtained in Examples and Comparative Examples was measured by the method described above. The measurement results are shown in Table 1.

[Evaluation of cushioning]
The cushioning properties of the non-woven fabrics of Examples and Comparative Examples were evaluated. The evaluation method is as follows. A non-woven fabric cut out in a size of 10 cm x 10 cm is used as a test piece, and three adult men who are skilled in evaluating the cushioning property as panelists touch the test piece to obtain the cushioning property (fluffiness). Was evaluated. The method of touching the test piece was not specified, and each panelist freely touched the test piece for evaluation. In such an evaluation, the cushioning property when the outer layer sheet taken out from a commercially available diaper was touched was used as an evaluation standard. Specifically, the outer layer sheet of the commercially available diaper "Mary's Love Embrace" (Kao Corporation, made in 2019, sold in China) is set to 3 points, and another commercially available diaper "Mary's Sarasara Air Through M size" (Kao Corporation) The outer layer sheet of the company, made in 2019, sold in Japan) was set as one point. The outer layer sheet is a sheet that forms the outer surface of the diaper. In the above evaluation criteria, it was evaluated that the higher the evaluation score, the more fluffy the test piece and the higher the cushioning property. In addition, when it was evaluated that the cushioning property was higher than that of the diaper having the evaluation standard of 3 points, the evaluation point was set to higher than 3 points and the highest evaluation was set to 5 points. The evaluation points were calculated by rounding the average value of the three panelists to an integer digit. The evaluation results are shown in Table 1.

As shown in Table 1, the non-woven fabrics of Examples 1 to 3 had a recovery thickness of 1.6 mm or more. Such a non-woven fabric was evaluated to have a larger recovery thickness and a higher cushioning property than Comparative Examples 1 to 4. From the results in Table 1, it can be seen that the non-woven fabrics in each example are superior in bulk recovery to compression and have good cushioning properties as compared with the non-woven fabrics in the comparative examples.

Claims (6)

A non-woven fabric for absorbent articles made of an air-through non-woven fabric.
It is composed of non-stretchable fibers, and the non-stretchable fibers contain fine fibers having a fiber diameter of 15 μm or less.
The ratio of the fine fibers to all the constituent fibers is 30% or more.
A non-woven fabric for absorbent articles having a basis weight of 30 g / m ² or less, flat surfaces on both sides, and a thickness of 1.6 mm or more after applying a load of ^{30 cN / cm 2 for 24 hours.} The nonwoven fabric for absorbent articles according to claim 1, wherein the non-stretchable fiber contains one or more resin components selected from the group consisting of polyethylene, polypropylene, and polyethylene terephthalate. The non-woven fabric for an absorbent article according to claim 1 or 2, which comprises a fiber having a fiber diameter of 20 μm or less. The nonwoven fabric for absorbent articles according to any one of claims 1 to 3, which has a basis weight of 28 g / m ^{2 or less.} An absorbent article comprising the non-woven fabric for an absorbent article according to any one of claims 1 to 4 as a constituent member. The absorbent article according to claim 5, wherein the constituent member is an exterior body forming an outer surface of the absorbent article.