JP2020171688A - Non-woven fabric for absorbent article, top sheet for absorbent article, and absorbent article including the same - Google Patents

Abstract

To provide non-woven fabric for an absorbent article whose absorbency of fluid such as loose passage while maintaining liquid absorbency and a texture, a top sheet including the same, and an absorbent article including the top sheet.SOLUTION: Non-woven fabric for an absorbent article includes a first fiber layer and a second fiber layer positioned on one main surface of the first fiber layer. The first fiber layer includes first core-sheath type composite fiber, the second fiber layer includes second core-sheath type composite fiber and cellulosic fiber, fiber of the first core-sheath type composite fiber is smaller than fiber of the second core-sheath type composite fiber, fiber of the first core-sheath type composite fiber ranges from 1.0 to 2.8 dtex, fiber of the second core-sheath type composite fiber ranges from 1.7 to 5.6 dtex, fiber of the cellulosic fiber ranges from 1.2 to 6.0 dtex, the second fiber layer includes 5 mass% to 40 mass% cellulosic fiber with total mass of the second fiber layer as reference.SELECTED DRAWING: None

Description

The present invention relates to a non-woven fabric for an absorbent article, a top sheet for an absorbent article, and an absorbent article containing the same.

Nonwoven fabrics having a two-layer structure have been proposed as top sheets for absorbent articles such as disposable diapers, sanitary napkins, incontinence pads and panty liners.

For example, Patent Document 1 is a non-woven fabric having at least a two-layer structure of a first fiber layer and a second fiber layer, and both the first fiber layer and the second fiber layer each have a specific fineness. The fiber diameter of the 1 fiber layer is larger than the fiber diameter of the 2nd fiber layer, and both the 1st fiber layer and the 2nd fiber layer are hydrophilic so that the degree of hydrophilicity is maintained even when they come into contact with water. We propose a non-woven fabric having the same hydrophilicity in both the first fiber layer and the second fiber layer (see claim 1). Further, Patent Document 1 includes a non-woven fabric thereof, a top sheet for an absorbent article in which a first fiber layer is arranged so as to face human skin, and a top sheet thereof, wherein the first fiber layer is made of human skin. An absorbent article is proposed that is placed so as to face the skin (see claims 6 and 7). Patent Document 1 describes that at least one selected from texture, wetback amount, liquid absorption time, diffusion length, repeatability, storage stability, etc. is improved (see [0014]).

Patent Document 2 is an absorbent article that receives excrement from the wearer, and is formed of an absorbent core containing 40% by weight or more of highly absorbent resin powder and a non-woven fabric covering the main surface of the absorbent core on the wearer side. A top comprising a topsheet and a backsheet covering the other main surface of the absorbent core, the topsheet abutting on the highly absorbent resin powder of the absorbent core and containing hydrophilic fibers which are natural and / or regenerated fibers. We propose an absorbent article having a lower part of the seat and an upper part of the top sheet which is arranged on the wearer side of the lower part of the top sheet and has a lower content of hydrophilic fibers than the lower part of the top sheet (see claim 1). Patent Document 2 describes that the absorbent article can be made thinner and the structure can be simplified, the moisture of excrement can be reliably absorbed, and the feel of the absorbent article can be improved ([0020]. ]reference).

Patent Document 3 is an absorbent article in which an absorbent layer is interposed between a front surface layer and a back surface layer. The surface layer contains a hydrophobic fiber and a hydrophilic fiber shorter than the hydrophobic fiber, and the hydrophobic fibers heat each other. Disclosed is an absorbent article that is fused and at least a portion of the hydrophilic fibers are aggregated and dispersed in the sheet, and at least a portion of the aggregated hydrophilic fibers is fused to the surface of the hydrophobic fibers. (See claim 1). Further, in Patent Document 3, when the surface layer is divided in the thickness direction and the liquid receiving side is the front surface portion and the absorption layer side is the back surface portion, the aggregate of hydrophilic fibers is not provided on the front surface portion and the back surface portion. Disclose an absorbent article provided only in a portion (see claim 4). Patent Document 3 describes that when a large amount of liquid is given, the liquid quickly permeates the surface layer and is absorbed by the absorption layer, and when a small amount of liquid or a rash is given, the dispersed hydrophilic fibers are described. It is described that moisture is retained by the aggregate, the surface of the surface layer can be made dry, the wearer is not moistened, and the wearing feeling is improved (see [0064]).

WO2017 / 171017A1 Japanese Unexamined Patent Publication No. 2009-327 Japanese Unexamined Patent Publication No. 2002-651

In recent years, absorbent articles are required to improve (improve) the absorbency of loose stools, watery stools, and diarrheal stools (hereinafter, also simply referred to as "loose stools") while maintaining liquid absorption performance and tactile sensation. It has become. Loose stool is an extremely viscous fluid and also contains water and oil. Since it contains oil, it is difficult to be absorbed by a highly absorbent polymer (SAP), and it is the top in terms of improving the absorbency of fluids such as loose stool. The non-woven fabric used for sheets and the like also needs to be improved. Patent Documents 1 to 3 do not mention this point, and there is room for further improvement in the non-woven fabric described in Patent Documents 1 to 3, the top sheet containing the non-woven fabric, and the absorbent article containing the top sheet. ..

The present invention relates to a non-woven fabric for an absorbent article, a non-woven fabric for an absorbent article, the top sheet containing the non-woven fabric, and an absorbent article including the top sheet, which have improved (improved) absorption of a fluid such as loose stool while maintaining liquid absorption performance and tactile sensation. The purpose is to provide.

As a result of diligent studies, the present inventors have conducted a non-woven fabric containing a first fiber layer and a second fiber layer, in which the first fiber layer contains a specific composite fiber and the second fiber layer is another specific non-woven fabric. When the composite fiber is contained and a specific amount of the cellulosic fiber is contained, a non-woven fabric for an absorbent article having improved (improved) absorption of fluid such as loose stool while maintaining liquid absorption performance and tactile sensation can be obtained. I found. Furthermore, they have found that such non-woven fabrics are suitable for use in topsheets and absorbent articles, and have completed the present invention.

That is, the present invention provides, as one gist, a non-woven fabric for absorbent articles.
A non-woven fabric containing a first fiber layer and a second fiber layer located on one main surface of the first fiber layer.
The first fiber layer contains a first core-sheath type composite fiber and contains.
The second fiber layer contains a second core-sheath type composite fiber and a cellulosic fiber.
The fineness of the first core-sheath type composite fiber is smaller than the fineness of the second core-sheath type composite fiber.
The fineness of the first core-sheath type composite fiber is 1.0 to 2.8 dtex.
The fineness of the second core-sheath type composite fiber is 1.7 to 5.6 dtex.
The fineness of the cellulosic fiber is 1.2 to 6.0 dtex.
The second fiber layer contains the cellulosic fiber at a ratio of 5% by mass to 40% by mass based on the total mass of the second fiber layer.

Further, in another gist, the present invention provides a top sheet containing a non-woven fabric for an absorbent article and an absorbent article containing the top sheet.

The non-woven fabric for absorbent articles of the embodiment of the present invention can further improve the absorbency of fluids such as loose stools while maintaining the liquid absorption performance and the tactile sensation. Therefore, the non-woven fabric for absorbent articles of the embodiment of the present invention can be suitably used for producing a top sheet and an absorbent article.

The non-woven fabric for absorbent articles according to the embodiment of the present invention
It includes a first fiber layer and a second fiber layer located on one of the main surfaces of the first fiber layer.
The first fiber layer contains a first core-sheath type composite fiber and contains.
The second fiber layer contains a second core-sheath type composite fiber and a cellulosic fiber.
The fineness of the first core-sheath type composite fiber is smaller than the fineness of the second core-sheath type composite fiber.
The fineness of the first core-sheath type composite fiber is 1.0 to 2.8 dtex.
The fineness of the second core-sheath type composite fiber is 1.7 to 5.6 dtex.
The fineness of the cellulosic fiber is 1.2 to 6.0 dtex.
The second fiber layer contains the cellulosic fibers in a proportion of 5% by mass to 40% by mass based on the total mass of the second fiber layer.

The first core-sheath type composite fiber is not particularly limited in terms of core component, sheath component, mass ratio (core / sheath ratio), etc., as long as the non-woven fabric for absorbent articles intended by the present invention can be obtained. It may be a concentric or eccentric core sheath type composite fiber. It is preferable that the first core-sheath type composite fiber is a concentric core-sheath type composite fiber because the thickness of the non-woven fabric is not excessively increased, the distance to the absorber is appropriate, and good liquid absorption performance is exhibited.

The first core-sheath type composite fiber is a low melting point resin and a high melting point resin having a melting point higher than that of the low melting point resin by, for example, 10 ° C. or more (that is, the melting point of the low melting point resin (° C.) ≤ the melting point of the high melting point resin- It is composed of two kinds of resins satisfying 10 (° C.)), a low melting point resin may form a sheath, and a high melting point resin may form a core. The difference between the melting point of the low melting point resin and the melting point of the high melting point resin is preferably 20 to 190 ° C., and the difference between the melting point of the low melting point resin and the melting point of the high melting point resin is more preferably 70 to 170 ° C. The difference between the melting point of the low melting point resin and the melting point of the high melting point resin is even more preferably 110 to 140 ° C.

The melting point of the low melting point resin is, for example, 100 to 170 ° C., preferably 110 to 150 ° C., and more preferably 120 to 140 ° C.
The melting point of the refractory resin is, for example, 150 to 290 ° C, preferably 190 to 280 ° C, and more preferably 230 to 270 ° C.
In the present specification, the melting point of the resin refers to the melting peak temperature determined by the DSC curve measured according to JIS K 7121.

Examples of the high melting point resin and the low melting point resin include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate and copolymers thereof; polypropylene and polyethylene (high density). A propylene copolymer (propylene-ethylene copolymer, propylene-butene-1-ethylene copolymer) mainly composed of polyethylene, low-density polyethylene, linear low-density polyethylene, etc., polybutene-1, and propylene. Polyester resins such as), ethylene-vinyl alcohol copolymers, and ethylene-vinyl acetate copolymers; polyamide resins such as nylon 6, nylon 12 and nylon 66; acrylic resins; polycarbonate, polyacetal, polystyrene and Engineering plastics such as cyclic polyolefins and one or more thermoplastic resins arbitrarily selected from those elastomers can be used as appropriate.

As a combination of high melting point resin and low melting point resin (high melting point / low melting point), for example, polypropylene / high density polyethylene, polypropylene / low density polyethylene, polypropylene / linear low density polyethylene, polyethylene terephthalate / high density polyethylene, polyethylene terephthalate. / Low density polyethylene, polyethylene terephthalate / linear low density polyethylene, polyethylene terephthalate / copolymer polyester, polypropylene / ethylene-propylene copolymer, polyethylene terephthalate / ethylene-propylene copolymer, nylon 6 / high density polyethylene, nylon 6 Examples include / low density polyethylene, nylon 6 / linear low density polyethylene, nylon 6 / polypropylene, polylactic acid / polyethylene, polylactic acid / polybutylene succinate, and polylactic acid / polybutylene succinate adipate, but combinations thereof. It is not limited to.

The combination of high melting point resin and low melting point resin is polyethylene terephthalate / high density polyethylene, polyethylene terephthalate / low density polyethylene, polyethylene terephthalate / linear low density polyethylene, polypropylene / high density polyethylene, polypropylene / low density polyethylene, polypropylene / direct Chain low density polyethylene is preferable, and polyethylene terephthalate / high density polyethylene and polypropylene / high density polyethylene are more preferable.

The mass ratio (core / sheath ratio) of the core component to the sheath component may be, for example, 80/20 to 40/60, preferably 70/30 to 50/50, and 65/35 to 55 /. It is more preferably 45.

The fineness of the first core-sheath type composite fiber is, for example, 1.0 to 2.8 dtex, preferably 1.5 to 2.6 dtex, and more preferably 1.7 to 2.3 dtex. When the fineness of the first core-sheath type composite fiber is 1.0 to 2.8 dtex, an excellent effect of obtaining a smooth tactile sensation is exhibited.
The fiber length of the first core-sheath type composite fiber is, for example, 10 to 100 mm, preferably 20 to 70 mm, more preferably 30 to 60 mm, and even more preferably 35 to 50 mm.

The second core-sheath type composite fiber is not particularly limited in terms of core component, sheath component, mass ratio (core / sheath ratio), etc., as long as the non-woven fabric for absorbent articles intended by the present invention can be obtained. It may be a concentric or eccentric core sheath type composite fiber. It is preferable that the second core-sheath type composite fiber is a concentric core-sheath type composite fiber because the thickness of the non-woven fabric is not excessively increased, the distance to the absorber is appropriate, and good liquid absorption performance is exhibited.

The second core-sheath composite fiber is a low melting point resin and a high melting point resin having a melting point higher than that of the low melting point resin by, for example, 10 ° C. or higher (that is, the melting point of the low melting point resin (° C.) ≤ the melting point of the high melting point resin- It is composed of two kinds of resins satisfying 10 (° C.)), a low melting point resin may form a sheath, and a high melting point resin may form a core. The difference between the melting point of the low melting point resin and the melting point of the high melting point resin is preferably 20 to 190 ° C., and the difference between the melting point of the low melting point resin and the melting point of the high melting point resin is more preferably 70 to 170 ° C. The difference between the melting point of the low melting point resin and the melting point of the high melting point resin is even more preferably 110 to 140 ° C.

The melting point of the low melting point resin is, for example, 100 to 170 ° C., preferably 110 to 150 ° C., and more preferably 120 to 140 ° C.
The melting point of the refractory resin is, for example, 150 to 290 ° C, preferably 190 to 280 ° C, and more preferably 230 to 270 ° C.

As the high melting point resin and the low melting point resin, the resin exemplified by the first core-sheath type composite fiber can be appropriately used in the same manner. As a combination of the high melting point resin and the low melting point resin (high melting point / low melting point), the combination exemplified by the first core-sheath type composite fiber can be appropriately used in the same manner.
The combination of high melting point resin and low melting point resin is polyethylene terephthalate / high density polyethylene, polyethylene terephthalate / low density polyethylene, polyethylene terephthalate / linear low density polyethylene, polypropylene / high density polyethylene, polypropylene / low density polyethylene, polypropylene / direct Chain low density polyethylene is preferable, and polyethylene terephthalate / high density polyethylene and polypropylene / high density polyethylene are more preferable.

The mass ratio (core / sheath ratio) of the core component to the sheath component may be, for example, 80/20 to 40/60, preferably 70/30 to 50/50, and 65/35 to 55 /. It is more preferably 45.

The fineness of the second core-sheath type composite fiber is, for example, 1.7 to 5.6 dtex, preferably 2.0 to 5.0 dtex, and more preferably 2.6 to 4.0 dtex. When the fineness of the second core-sheath type composite fiber is 1.7 to 5.6 dtex, it has an excellent effect of reducing the amount of wet back.
The fiber length of the second core-sheath type composite fiber is, for example, 10 to 100 mm, preferably 20 to 70 mm, more preferably 30 to 60 mm, and even more preferably 35 to 55 mm.

The fineness of the first core-sheath type composite fiber is smaller than the fineness of the second core-sheath type composite fiber, and the difference between the fineness of the first core-sheath type composite fiber and the fineness of the second core-sheath type composite fiber is For example, it can be 0.5 to 4.0 dtex, preferably 0.7 to 3.0 dtex, and more preferably 1.0 to 2.0 dtex. When the fineness of the first core-sheath type composite fiber is smaller than the fineness of the second core-sheath type composite fiber, it has an excellent effect of achieving both a smooth feel and a reduction in the amount of wet back.

The type of cellulosic fiber is not particularly limited as long as the non-woven fabric for absorbent articles intended by the present invention can be obtained.
Examples of cellulosic fibers include natural fibers such as cotton and hemp; regenerated fibers such as viscose rayon, cupra, and solvent-spun cellulosic fibers (eg, lenting lyocell® and tencel®). be able to. Since cellulosic fibers have both hydrophilic and oil-rich properties, the inclusion of cellulosic fibers in the second fiber layer allows fluids containing water and oil, such as loose stools, to return from the absorber (wetback). It is presumed that the cellulosic fibers have the effect of absorbing fluid such as loose stool and making it difficult for the liquid to return to the surface of the first fiber layer of the non-woven fabric.

The cellulosic fiber preferably contains at least one selected from cotton, viscose rayon, and solvent-spun cellulosic fiber, and more preferably viscose rayon. When the cellulosic fiber contains cotton, viscose rayon, or solvent-spun cellulosic fiber, it has an excellent effect of obtaining a soft touch. Viscose rayon has a lower degree of crystallinity than cotton and solvent-spun cellulose fibers and has more amorphous parts, so it has higher water absorption and oil absorption. Viscose rayon has a fluid containing water and oil such as loose stool. It is presumed that the effect of absorbing fluid such as loose stool and making it difficult for the liquid to return to the surface of the first fiber layer of the non-woven fabric when the liquid returns from the absorber is higher. Therefore, when viscose rayon is contained as the cellulosic fiber, it has good water absorbency such as loose stool, and particularly has an excellent effect of reducing the amount of wet back.
Cotton tends to form fiber lumps (aggregates of fibers) inside the second fiber layer. When a fiber mass is contained inside the second fiber layer, the thickness of the second fiber layer tends to be thicker, the distance between the surface of the non-woven fabric on the first fiber layer side and the absorber becomes longer, and the liquid returns from the absorber. The amount may decrease. Further, by forming the fiber mass, the number of places where the second core-sheath type composite fibers come into contact with each other increases, and it may be easy to maintain the strength of the non-woven fabric.
The solvent-spun cellulose fiber tends to increase the rigidity and softness of the non-woven fabric, and the bulk of the second fiber layer is less likely to collapse when a load is applied to the non-woven fabric. If the bulk of the second fiber layer is less likely to collapse under load, the distance between the surface of the nonwoven fabric on the first fiber layer side and the absorber becomes longer, and the amount of liquid returned from the absorber may decrease.

Further, it is preferable to contain cellulosic fibers having a chrysanthemum-shaped fiber cross section, and more preferably to contain viscose rayon having a chrysanthemum-shaped fiber cross section. In this case, since the surface area of the fiber is larger and the fiber has streaks in the fiber axis direction, the fluid such as loose stool can be easily diffused in the second fiber layer and can be absorbed in a relatively wide area in the absorber. It has an excellent effect of making it easier to reduce the amount of wet back.

The fineness of the cellulosic fiber is, for example, 1.2 to 6.0 dtex, preferably 1.5 to 5.0 dtex, and more preferably 2.0 to 4.0 dtex. When the fineness of the cellulosic fiber is 1.2 to 6.0 dtex, it has an excellent effect of improving the absorption of a fluid such as loose stool.
The fiber length of the cellulosic fiber is, for example, 10 to 100 mm, preferably 15 to 80 mm, more preferably 20 to 60 mm, and even more preferably 30 to 55 mm.

It is preferable that the fineness or fiber length of the cellulosic fiber has a uniform fineness or fiber length because it is difficult for the cellulosic fiber to form an aggregate (nep) in the second fiber layer. When the cellulosic fibers form an aggregate in the second fiber layer, the second core-sheath type composite fiber and the cellulosic fiber contained in the second fiber layer are mixed relatively non-uniformly, and in a place where the aggregate does not exist. Has a relatively large number of adhesion points between the second core-sheath type composite fibers, making it difficult for fluids such as loose stools to pass through the non-woven fabric, and fluids such as loose stools tend to remain at those points, resulting in reduced liquid absorption, especially wet. It may be difficult to reduce the amount of backing. Cellulose-based fibers having a uniform fineness or fiber length include regenerated fibers, which are chemical fibers. It is more preferable that the fineness and fiber length of the cellulosic fiber have uniform fineness and fiber length, respectively.
When the fineness or fiber length of the cellulosic fiber has a non-uniform fineness or fiber length, the cellulosic fiber is more likely to form a fiber mass (aggregate of fibers) in the second fiber layer, but forms a fiber mass. By doing so, the number of places where the second core-sheath type composite fibers come into contact with each other increases, and it may be easy to maintain the strength of the non-woven fabric.

The second fiber layer can contain, for example, 5% by mass to 40% by mass (mixture ratio) of the cellulosic fibers based on the total mass of the second fiber layer, and 10% by mass to 30% by mass. It is preferably contained in a proportion of%, more preferably in a proportion of 15% by mass to 25% by mass, and even more preferably in a proportion of 17% by mass to 23% by mass. When the second fiber layer contains the cellulosic fiber at a ratio (mixture ratio) of 5% by mass to 40% by mass based on the total mass of the second fiber layer, the absorbability of a fluid such as loose stool is good. In addition, it has an excellent effect of improving the strength of the non-woven fabric.
The second fiber layer can contain, for example, 95% by mass to 60% by mass, and 90% by mass to 70% by mass, based on the total mass of the second fiber layer. It is preferably contained in a proportion of mass%, more preferably in a proportion of 85% by mass to 75% by mass, and even more preferably in a proportion of 83% by mass to 77% by mass.

The second fiber layer is the ratio of the number of fibers of the second core-sheath type composite fiber contained in the second fiber layer to the number of fibers of the cellulose-based fiber (number of fibers of the second core-sheath type composite fiber / fiber of the cellulose-based fiber). The number of fibers) is preferably 0.6 to 10, more preferably 1.0 to 4.0, and even more preferably 1.2 to 3.0. When the value of the number of fibers of the second core-sheath type composite fiber / the number of fibers of the cellulosic fiber is 0.6 or more, the non-woven fabric is strong because there are more sufficient adhesion points between the fibers by the second core-sheath type composite fiber. Is more easily obtained, and the liquid absorption performance is more likely to be improved. When the value of the number of fibers of the second core-sheath type composite fiber / the number of fibers of the cellulosic fiber is 10 or less, it is easy to obtain the effect of improving the liquid absorption performance by containing the cellulosic fiber.
The ratio R of the number of fibers of the second core-sheath type composite fiber to the number of fibers of the cellulosic fiber in the second fiber layer (the number of fibers of the second core-sheath type composite fiber / the number of fibers of the cellulosic fiber) is the following formula. Calculated by
R = As × Dc × Lc / (Ds × Ls × Ac)
In the formula, As represents the mixing ratio (mass%) of the second core-sheath type composite fiber in the second fiber layer.
Ds represents the fineness (dtex) of the second core-sheath type composite fiber.
Ls represents the fiber length (mm) of the second core-sheath type composite fiber.
Ac represents the mixing ratio (mass%) of the cellulosic fiber in the second fiber layer.
Dc represents the fineness (dtex) of cellulosic fibers.
Lc represents the fiber length (mm) of the cellulosic fiber.

The basis weight of the entire non-woven fabric is preferably 10 to 80 g / m ² , more preferably 15 to 50 g / m ² , and even more preferably 17 to 40 g / m ² .
If the overall basis weight of disposable diaper nonwoven well as low as possible it is cost aspects, the basis weight of that case is preferably from 10 to 50 g / ^{m 2,} and more preferably 15 to 40 g / ^{m 2.}

The thickness of the non-woven fabric is preferably 0.10 to 4.0 mm, more preferably 0.25 to 3.0 mm, and even more preferably 0.30 to 2.0 mm. In the case of disposable diapers, the thickness of the non-woven fabric may be as low as possible in terms of cost, and in that case, the thickness is preferably 0.10 to 3.0 mm, preferably 0.30 to 2.0 mm. More preferred. In the present invention, the thickness of the non-woven fabric refers to the thickness measured with a load of 294 Pa applied to the non-woven fabric.

Specific volume of the nonwoven fabric is preferably 5~150cm ³ / g, more preferably from 7~120cm ³ / g, more preferably from 10 to 100 cm ³ / g. In the present invention, the specific volume of the non-woven fabric refers to a value obtained by calculation from the above-mentioned basis weight and thickness.

Basis weight of the first fibrous layer, for example, be a 3~40g / ^{m 2,} it is preferably 4~25g / ^{m 2,} and more preferably 5 to 15 g / ^{m 2.}

Basis weight of the second fiber layer may be, for example, 3~40g / ^{m 2,} is preferably 5 to 30 g / ^{m 2,} and more preferably 8 to 20 g / ^{m 2.}

The basis weight of the first fiber layer is preferably smaller than the basis weight of the second fiber layer.
The difference in basis weight of the basis weight and the second fibrous layer of the first fibrous layer may be, for example, 0 to 10 g / ^{m 2,} is preferably 1-8 g / ^{m 2,} is 2 to 6 g / ^{m 2} Is even more preferable.
When the basis weight of the first fiber layer is smaller than the basis weight of the second fiber layer, it has an excellent effect of reducing the amount of wet back.

The nonwoven fabric of the embodiment of the present invention has a structure in which a first fiber layer and a second fiber layer are laminated. In the first fiber layer and the second fiber layer, the fibers may be adhered to each other in each fiber layer, and the fibers may be adhered to each other between the first fiber layer and the second fiber layer.

The first fiber layer and the second fiber layer of the embodiment of the present invention can be produced by using various methods for producing a fiber web. As long as the non-woven fabric for absorbent articles intended by the present invention can be obtained, the production method thereof is not particularly limited. As such a manufacturing method, for example, a card method such as parallel web, cross web, Chris cross web, semi-random web and random web, an air array method and the like can be exemplified.

The non-woven fabric for absorbent articles of the embodiment of the present invention can be produced by superimposing the first fiber web and the second fiber web and integrating them. As long as the non-woven fabric for absorbent articles intended by the present invention can be obtained, the production method thereof is not particularly limited. Examples of such a manufacturing method include an air-through method (hot air penetration type heat treatment method), a hot air blowing type heat treatment method, a heat roll method, an infrared heat treatment method, a needle punch method, and the like. Penetration type heat treatment method) is preferable because it is easy to obtain a non-woven fabric having a good texture.
The fibers of the first fiber layer and the fibers of the second fiber layer of the integrated non-woven fabric may be adhered to each other.
The non-woven fabric for absorbent articles of the embodiment of the present invention may further have an additional layer that the non-woven fabric usually has, if desired. The non-woven fabric for an absorbent article according to the embodiment of the present invention preferably has a two-layer structure including a first fiber layer and a second fiber layer.

The non-woven fabric for absorbent articles of the embodiment of the present invention may be subjected to additional processing such as embossing, if necessary, and may have such an additional form and shape.

The non-woven fabric for absorbent articles according to the embodiment of the present invention preferably has a tensile strength in the MD direction (mechanical direction) of 10 to 45 N / 5 cm, more preferably 15 to 40 N / 5 cm, and 20 to 40 N / 5 cm. It is more preferably 35 N / 5 cm.
When the tensile strength in the MD direction of the non-woven fabric for absorbent articles according to the embodiment of the present invention is 10 to 45 N / 5 cm, it has a good tactile sensation, and the width of the nonwoven fabric during product processing of the absorbent article is included. It has an excellent effect of suppressing.

The non-woven fabric for absorbent articles according to the embodiment of the present invention preferably has a tensile strength in the CD direction (direction orthogonal to the MD direction) of 2 to 12 N / 5 cm, and more preferably 3 to 10 N / 5 cm. It is preferably 5 to 8 N / 5 cm, more preferably 5 to 8 N / 5 cm.
When the tensile strength of the non-woven fabric for absorbent articles of the present invention in the CD direction is 2 to 12 N / 5 cm, it has a good tactile sensation, and the width of the nonwoven fabric during product processing of the absorbent article is included. It has an excellent effect of suppressing.

The non-woven fabric for absorbent articles according to the embodiment of the present invention preferably has an elongation rate in the MD direction of 20 to 80%, more preferably 30 to 70%, and even more preferably 40 to 60%. ..
The non-woven fabric for absorbent articles according to the embodiment of the present invention preferably has an elongation rate in the CD direction of 20 to 130%, more preferably 40 to 110%, and even more preferably 60 to 90%. ..

In the non-woven fabric for absorbent articles of the embodiment of the present invention, the stress at 10% elongation in the MD direction is preferably 1 to 20 N / 5 cm, more preferably 2 to 10 N / 5 cm, and 3 to 7 N / It is more preferably 5 cm.

In the non-woven fabric for absorbent articles of the embodiment of the present invention, the total of the rigidity in the MD direction and the rigidity in the CD direction is preferably 5 to 25 mN · cm, preferably 6 to 20 mN · cm. More preferably, it is 7 to 15 mN · cm.
The non-woven fabric for absorbent articles according to the embodiment of the present invention can obtain a soft tactile sensation and is absorbent when the total of the rigidity in the MD direction and the rigidity in the CD direction is 5 to 25 mN · cm. It has an excellent effect of being hard to tear when used as a member of an article. Rigidity and softness are measured according to the 41.5 ° cantilever method described in Examples.

The non-woven fabric for absorbent articles of the embodiment of the present invention can be used for various absorbent articles such as disposable diapers, sanitary napkins, incontinence pads and panty liners. Since the non-woven fabric for absorbent articles of the embodiment of the present invention has an excellent tactile sensation, it can be used for any member as long as it is various absorbent articles. The non-woven fabric for absorbent articles according to the embodiment of the present invention can be suitably used for a top sheet or a second sheet of an absorbent article because it has excellent tactile sensation and liquid absorbing properties, but the absorbent article can be used with the wearer's skin. It is particularly preferred to use it on the topsheet where urine, menstrual blood and loose stools come into contact first and are drained from the wearer.

The non-woven fabric for absorbent articles according to the embodiment of the present invention preferably contains a non-woven fabric for absorbent articles for absorbing a fluid containing water and oil, and is for an absorbent article for absorbing a fluid containing water and oil. It is more preferably a non-woven fabric, more preferably a non-woven fabric for an absorbent article for absorbing loose stool, and more preferably a non-woven fabric for an absorbent article for absorbing loose stool. The non-woven fabric for absorbent articles according to the embodiment of the present invention is particularly preferable as long as it is a non-woven fabric for disposable diapers because it has good urine absorption performance and loose stool absorbency, and also has a good tactile sensation.

Furthermore, the present invention can provide various absorbent articles, including such non-woven fabrics for absorbent articles. In particular, the first fiber layer of the topsheet for absorbent articles of the embodiment of the present invention may be arranged closer to the skin of the user to provide an absorbent article containing the topsheet for absorbent articles. it can.

Furthermore, the present invention can provide the various absorbent articles described above. The absorbent article of the embodiment of the present invention preferably contains an absorbent article for absorbing a fluid containing water and oil, and more preferably contains an absorbent article for absorbing loose stool.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but these Examples are only one aspect of the present invention, and the present invention is not limited to these Examples.

The [fibers] used to produce the non-woven fabrics of Examples and Comparative Examples are shown below.
1st core sheath type composite fiber: The core component is polyethylene terephthalate resin (PET) having a melting point of 256 ° C., and the sheath component is a high density polyethylene (HDPE) resin having a melting point of 130 ° C., and the core component and the sheath component in the fiber cross section Concentric core-sheath type composite fiber with a core-sheath ratio (core / sheath mass ratio) of 60/40, a fineness of 2.0 dtex (fiber diameter of 15 μm), and a fiber length of 45 mm (hereinafter also referred to as “composite fiber 1”). )
Second core sheath type composite fiber: The core component is polyethylene terephthalate resin (PET) having a melting point of 256 ° C., the sheath component is a high density polyethylene (HDPE) resin having a melting point of 130 ° C., and the core component and the sheath component in the fiber cross section Concentric core-sheath type composite fiber with a core-sheath ratio (core / sheath mass ratio) of 60/40, a fineness of 3.3 dtex (fiber diameter 19 μm), and a fiber length of 51 mm (hereinafter also referred to as “composite fiber 2”). )

Rayon fiber A: Viscose rayon with a fineness of 1.4 dtex and a fiber length of 44 mm (trade name: Corona CD, manufactured by Daiwa Bow Rayon Co., Ltd.) (hereinafter also referred to as "rayon A")
Rayon fiber B: Viscose rayon with a fineness of 1.7 dtex and a fiber length of 40 mm (trade name: Corona CD, manufactured by Daiwa Bow Rayon Co., Ltd.) (hereinafter also referred to as "rayon B")
Rayon fiber C: Viscose rayon with a fineness of 2.2 dtex and a fiber length of 51 mm (trade name: Corona CD, manufactured by Daiwa Bow Rayon Co., Ltd.) (hereinafter also referred to as "rayon C")
Rayon fiber D: Viscose rayon with a fineness of 3.3 dtex and a fiber length of 51 mm (trade name: Corona CD, manufactured by Daiwa Bow Rayon Co., Ltd.) (hereinafter also referred to as "rayon D")
Rayon fiber E: Viscose rayon with a fineness of 5.6 dtex and a fiber length of 51 mm (trade name: Corona CD, manufactured by Daiwa Bow Rayon Co., Ltd.) (hereinafter also referred to as "rayon E")
The fiber cross sections of the rayon fibers A to E were all chrysanthemum-shaped irregular cross sections.

Lyocell fiber: Solvent-spun cellulose fiber with a fineness of 1.7 dtex, a fiber length of 40 mm, and a circular fiber cross section (Lyocell (trade name) manufactured by Lenzing) (hereinafter also referred to as "lyocell").
Cotton fiber: Cotton with a fineness of 1.0 to 5.0 dtex (average 2.5 dtex) and fiber length of 10 to 60 mm (average fiber length 20 mm) (MSD (trade name) manufactured by Marusan Sangyo Co., Ltd.) (hereinafter "cotton") Also called)

[Example 1]
The composite fiber 1 was used as the first core-sheath type composite fiber, and the first fiber web to be the first fiber layer was manufactured by using a parallel card machine. The basis weight of the first fiber web was about 8 g / m ² .
The composite fibers 2 and rayon B are weighed so that the composite fiber 2 is 90% by mass as the second core-sheath type composite fiber and the rayon B is 10% by mass as the cellulosic fiber, and these are sufficiently mixed and then the parallel card. The machine was used to produce a second fiber web, which is the second fiber layer. The basis weight of the second fiber web was about 12 g / m ² .
The first fiber web and the second fiber web were superposed and heat-treated by a hot air penetration type heat treatment machine. When performing the heat treatment, the first fiber web was placed in contact with the conveyor net of the hot air penetrating heat treatment machine. The heat treatment is performed by blowing hot air at 135 ° C. from the second fiber web side, and the constituent fibers of each fiber web are heat-bonded to each other by the sheath components of the composite fiber 1 and the composite fiber 2, and the first fiber web and the second fiber web are heat-bonded to each other. Was heat-bonded and integrated to obtain the non-woven fabric of Example 1. The basis weight of the non-woven fabric of Example 1 was about 20 g / m ² .

[Examples 2 to 10] and [Comparative Examples 1 to 3]
With respect to Examples 2 to 10 and Comparative Examples 1 to 3, the fibers shown in Tables 1 to 3 were used, and the same method as the method for producing the non-woven fabric of Example 1 described above was used. Nonwoven fabrics of Comparative Examples 1 to 3 were obtained.

The non-woven fabrics of Examples and Comparative Examples were measured and evaluated according to the methods shown below.

[Non-woven fabric thickness, specific volume]
The thickness of the non-woven fabric (including the non-woven fabric sample) was measured using a thickness measuring machine (trade name THICKNESS GAUGE model CR-60A manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.) with a load of 294 Pa applied to the non-woven fabric. ..
The specific volume was calculated from the basis weight and thickness.

[Tensile strength and elongation of non-woven fabric, stress during elongation of 10%]
According to JIS L 1913 (2010) 1096 6.312.1 A method (strip method), using a constant velocity tension type tensile tester, the width of the sample piece is 5 cm, the grip interval is 10 cm, and the tensile speed is 30 ± 2 cm / min. The tensile test was carried out under the conditions of (1), and the load value (tensile strength) at the time of cutting, the elongation rate, and the stress at the time of 10% elongation were measured. The tensile test was performed with the MD direction (mechanical direction) and the CD direction (direction orthogonal to the MD direction) of the nonwoven fabric as the tensile directions. All the values were measured for three samples and the average value was shown.

[Rigidity]
The stiffness of the non-woven fabric was measured in each of the MD direction and the CD direction according to the 41.5 ° cantilever method of JIS L 1913 (2010). At the time of measurement, a paper pattern of the same size as the non-woven fabric was laid under the non-woven fabric for measurement.

[Tactile sensation (smoothness, softness)]
A sensory evaluation was performed by 12 panelists. The sensory evaluation was given by each panelist according to the following five criteria, and the average value of the evaluations of 12 persons was calculated.
Sensory evaluation criteria for smoothness 5: Very smooth 4: Smooth 3: Normal 2: Slightly rough 1: Roughness Sensory evaluation criteria for softness 5: Very soft 4: Soft 3: Normal 2 : Slightly hard 1: Hard

The absorbability of the nonwoven fabrics of Examples and Comparative Examples was evaluated by producing a liquid-absorbent article for evaluation.
[Manufacturing of absorbent articles]
A commercially available disposable disposable diaper (Daio Paper Corporation) whose inseam is composed of a liquid absorbing part consisting of a top sheet, a second sheet, and an absorber, and a leak-proof sheet that prevents moisture from leaking to the outside. The top sheet was peeled off from the trade name GOO.N (registered trademark), and the non-woven fabrics of the above-mentioned Examples and Comparative Examples were laminated in place of the removed top sheet to obtain an absorbent article for evaluation. At the time of laminating, the first fiber layer was arranged so as to face outward, and the second fiber layer was arranged so as to face the second sheet. Using this absorbent article for evaluation, the liquid absorbency (liquid absorption time, wet back, non-woven fabric surface diffusion length) of the non-woven fabrics of Examples and Comparative Examples was evaluated.

[Wetback (saline)]
The wet backs of the non-woven fabrics of Examples and Comparative Examples were evaluated by the following methods.
(1) In order to measure the amount of wet back, the following items were prepared.
Absorbent article for evaluation of the above-mentioned Examples and Comparative Examples Plate with injection tube (inner diameter 2.5 cm at the bottom of the tube)
0.9% saline (colored with blue dye, viscosity at 37 ° C. is 1.4 mPa · s)
Filter paper (ADVANTEC (registered trademark) No. 2 manufactured by Toyo Filter Paper Co., Ltd.) 10 cm x 10 cm
Weight (5 kg) 10 cm x 10 cm

(2) Method The amount of wet back was measured according to the following procedure.
(I) The absorbent article for evaluation was arranged so that the non-woven fabric (vertical 42 cm × horizontal 21 cm) faced upward, and a plate with an injection tube was placed on it.
(Ii) 50 ml of physiological saline warmed to about 37 ° C. was injected from a cylinder. The saline solution was left until it disappeared from the surface of the non-woven fabric (the saline solution could not be confirmed as a liquid).
(Iii) The plate with the injection tube was removed and allowed to stand for 10 minutes.
(Iv) A filter paper (30 sheets) whose mass was measured in advance was placed on a non-woven fabric, and a 5 kg weight was placed on the filter paper for 20 seconds. Then, the mass of the filter paper was measured. The difference between the mass of the filter paper before being placed on the non-woven fabric and the mass of the filter paper after being placed on the non-woven fabric and further placing the weight corresponds to the amount of wet back.
(V) Returning to (i) above, (i) to (iv) were repeated and measurement was performed three times. Wetback was evaluated a total of 4 times.
In addition, Examples 11 to 19 and Comparative Examples 11 to 14 were evaluated only twice in total, and the total amount described later was also used as the total amount of two times.

Three samples were prepared for one sample (nonwoven fabric). The average value of the wetback amount measured for each of the three samples was taken as the wetback amount of the sample.
The results are shown in the table. The smaller the amount of water exuding from the non-woven fabric, the less stuffy the human skin is, so the wetback value is preferably small.
The wetback amount can also be evaluated by measuring the wetback amount four times and using the total amount. Due to the small total amount of wet bags measured multiple times (specifically 4 times), when this non-woven fabric is actually used as a top sheet for absorbent articles such as paper diapers and sanitary napkins, the top sheet becomes urine and Even if menstrual blood is absorbed multiple times, the amount of urine and menstrual blood returned to the non-woven fabric surface on the first fiber layer side, that is, the surface in contact with the skin, is reduced, improving the comfort and usability of the wearer. It is considered that even if the same absorbent article is continuously worn, it is less likely to feel uncomfortable.

[Liquid absorption time (saline)]
In the wetback measurement, the liquid absorption time was measured during the first to fourth measurements. The liquid absorption time was measured by measuring the time during which the physiological saline was invisible from the surface of the non-woven fabric (the physiological saline was not confirmed as a liquid) from the injection of the physiological saline, and used as the liquid absorption time.
The results are shown in Table 1. It is preferable that the liquid absorption time (seconds) has a small value because the human skin does not get stuffy when it is absorbed in a shorter time.
The liquid absorption time is the time required for the non-woven fabric to absorb the liquid and the liquid does not exist on the surface, and the shorter the liquid absorption time, the more preferable. When the obtained non-woven fabric is used as the top sheet of an absorbent article due to the short liquid absorption time, the top sheet quickly absorbs urine and menstrual blood, and the surface in contact with the skin, that is, the first fiber layer of the non-woven fabric. The time until the liquid disappears from the surface on the side is shortened, the dry feeling of the non-woven fabric is improved, and the comfort and usability of the absorbent article wearer are improved.

[Wet back (milk)]
[Liquid absorption time (milk)]
Milk warmed to about 37 ° C as pseudo loose stool instead of physiological saline in wet back (saline) and liquid absorption time (saline) (trade name: delicious milk, manufactured by Meiji Co., Ltd., temperature 37 ° C) The viscosity of the above was 1.7 mPa · s), and the measurement was carried out using 50 ml.

[Non-woven fabric surface diffusion length (milk)]
After the 1st to 4th measurement of the liquid absorption time, when the plate with the injection tube was removed, the lengths of the milk-absorbed portions of the non-woven fabrics of Examples and Comparative Examples in the vertical direction were measured, and 1 to 1 respectively. The diffusion length was set to the 4th time.

[Spot absorbency (milk)]
For the non-woven fabrics of Examples 5, 7 and 9, one "Kim Towel (registered trademark)" manufactured by Nippon Paper Cresia Co., Ltd. is folded in four under the non-woven fabric with the first fiber layer facing up (length 16.5 cm, width 19. A stainless steel plate (length 5 cm, width 22 cm, thickness 0.5 cm, mass 360 g, hole diameter 1.5 cm, between the centers of the holes) laid in a state of (0 cm) and with holes made at equal intervals on the non-woven fabric. Place a distance of 2.0 cm) and pipette the non-woven fabric in the hole with milk warmed to about 37 ° C (trade name: delicious milk, manufactured by Meiji Co., Ltd., viscosity at 37 ° C, 1.7 mPa · s). (Manufactured by AS ONE Co., Ltd., trade name: 1-4655-01 Polyspot 1 mL), 1 drop (about 0.03 g) was dropped, and it was observed whether or not it was absorbed by the non-woven fabric at room temperature (20 ° C.). If the liquid no longer exists on the surface of the non-woven fabric on the first fiber layer side one minute after the milk is dropped on the non-woven fabric, it is regarded as "spot-absorbent" and the liquid is on the surface of the non-woven fabric on the first fiber layer side. If is still present, it is defined as "no spot absorption".

In Tables 1 to 3, Examples 1 to 3 and Comparative Examples 1 and 2 were produced and evaluated in the summer, and Examples 4 to 10 and Comparative Example 3 were produced and evaluated in the winter. A slight difference may occur in the evaluation results, but the degree of the difference does not affect that Examples 1 to 10 are Examples and Comparative Examples 1 to 3 are Comparative Examples. In Tables 1 to 3, the liquid absorption performance was examined in consideration of both the total of 2 times and the total of 4 times.

The non-woven fabrics of Examples 1 to 10 are all excellent in the liquid absorption time and wet back of physiological saline, the liquid absorption time and wet back of milk, and the tactile sensation (smoothness and softness).

On the other hand, in Comparative Example 1, the mixing ratio of the cellulosic fibers in the second fiber layer is high, and further improvement is required in the total wet back of the physiological saline solution.

In Comparative Example 2 and Comparative Example 3, the second fiber layer does not contain cellulosic fibers, and further improvement in tactile sensation (smoothness and softness) is required. Regarding the amount of the first wet-back of the physiological saline solution, the non-woven fabrics of Examples 1 to 10 gave better results than the non-woven fabrics of Comparative Examples 2 and 3. It is considered that the amount of wet back was reduced by the cellulose fibers absorbing the liquid returning from the absorber to the surface of the non-woven fabric.

Comparing Examples 1 to 3 with Comparative Example 2, the total wet back of milk was a good result in Examples 1 to 3 in which the second fiber layer contained cellulosic fibers. Comparing Examples 4 to 10 with Comparative Example 3, the total wet back of milk was a good result in Examples 4 to 10 in which the second fiber layer contained cellulosic fibers. In Comparative Example 2 and Comparative Example 3, the total liquid absorption time of milk is short, and milk is quickly transferred to the absorber, but a fluid containing oil such as milk is absorbed by the super absorbent polymer (SAP) of the absorber. It is difficult to do so, and it is thought that it spreads and accumulates at the top of the absorber, which appears as a large amount of wet back. It is considered that the liquid absorption time could be controlled and the wetback amount could be reduced by containing the cellulosic fibers in the second fiber layer as in Examples 1 to 3 and Examples 4 to 10.

Next, the examples are compared with each other.
Focusing on the types of cellulosic fibers, Examples 5 and 9 are similar non-woven fabrics except that the cellulosic fibers are rayon B (viscose rayon) and lyocell (solvent-spun cellulose fibers), respectively. In the total wetback of physiological saline and the total wetback of milk, Example 5 gave better results.

The non-woven fabric surface diffusion length of milk was larger in Example 5 in which the cellulosic fiber was rayon B (viscose rayon). It is considered that this is because the fiber cross section of rayon B (viscose rayon) is chrysanthemum-shaped and has a large surface area, and has streaks in the fiber axis direction so that milk can easily be transmitted, and as a result, it is easily diffused in the second fiber layer. Then, by being diffused, it is absorbed in a wide area in the absorber, and as described above, the liquid absorption time can be controlled by containing the cellulosic fiber in the second fiber layer. As a result, Example 5 It is considered that this led to a reduction in the total wetback amount of milk.

Regarding the spot absorbency of milk, Examples 5 and 7 in which the cellulosic fibers are rayon B or D (biscous rayon) do not have spot absorbency, and Example 9 in which the cellulosic fibers are lyocell (solvent-spun cellulose fibers) spot absorb. Although the result was that there was a property, it is considered that Example 9 containing lyocell (solvent-spun cellulose fiber) had spot absorption, so that the liquid was likely to return and the amount of wet back was relatively large.

Further, Examples 7 and 10 are the same non-woven fabrics except that the cellulosic fibers are rayon D (viscose rayon) and cotton, respectively, and the fineness is slightly different, but the total wet bag of physiological saline is used. And in the total wetback of milk, Example 7 gave better results. This is because the viscose rayon has a uniform fineness and fiber length as compared with cotton, so that the viscose rayon and the second core-sheath type composite fiber are mixed relatively uniformly in the second fiber layer, and the milk is the second. It is considered that this is because it is relatively difficult to remain in the fiber layer.

Focusing on the fineness of the cellulosic fiber, Example 4, Example 5, Example 6, Example 7, and Example 8 are the same non-woven fabric except that the fineness of the cellulosic fiber viscose rayon is different. However, in the total wet bag of physiological saline, Examples 5 to 8 gave better results.

Focusing on the mixing ratio of the cellulosic fibers, Examples 1 to 3 are the same non-woven fabric except that the mixing ratio of the cellulosic fibers viscose rayon is different, but in the total wet bag of milk, Example 2 is more. It was a good result.

[Examples 11-19] and [Comparative Examples 11-14]
For Examples 11 to 19 and Comparative Examples 11 to 14, the fibers shown in Tables 4 to 6 were used, and the same method as the method for producing the non-woven fabric of Example 1 described above was used. Nonwoven fabrics of Comparative Examples 11 to 14 were obtained.
With respect to the nonwoven fabrics of Examples 11 to 19 and Comparative Examples 11 to 14, diapers were produced as absorbent articles according to the above-mentioned method, and measurements and evaluations were carried out. The results are shown in Tables 4-6.

For Examples 11-13 and Comparative Examples 11-12, the mixing ratio was changed using 3.3 dtex rayon D as the cellulose fiber. In Example 13 (30% rayon D mixture), the balance of wetback with saline and milk was better. In Example 13, since the balance between the number of fibers of the second core-sheath type composite fiber and the number of cellulose fibers is better, the number of adhesion points between the second core-sheath type composite fibers is more appropriate, and the liquid residue in the second fiber layer is more. It is less likely to occur, and the adhesion point between the second core-sheath type composite fiber and the cellulosic fiber is more moderate, and the adhesion point is more moderately peeled off during liquid absorption, and the liquid residue in the second fiber layer. Is presumed to be less likely to occur.
The wetback of Examples 11 to 13 with physiological saline is equal to or higher than that of Comparative Example 11 (100% second core sheath type composite fiber), and in particular, Examples 11 to 13 are Comparative Examples in the first wetback. It was better than 11. In addition, the wet back of the milk loose stools of Examples 11 to 13 was slightly improved as compared with Comparative Example 11 (100% second core sheath type composite fiber). The surface diffusibility (total) of the non-woven fabrics of Examples 11 to 13 was equal to or higher than that. In addition, as will be described later, the performance of the napkin is significantly improved in the examples as compared with the comparative example (100% of the second core-sheath type composite fiber), and therefore, under the condition that the amount of liquid is small. It can be seen that it is more suitable for diapers (newborns) and napkins that require the performance of.
In Comparative Example 12 (mixing ratio of rayon D: 50%), the processability in the production of the non-woven fabric was not sufficient, and the non-woven fabric was too soft to perform the cutting process, and the fibers were likely to fall off from the cut surface. In addition, delamination between the first fiber layer and the second fiber layer was likely to occur.

For Examples 14-16 and Comparative Example 13, cotton was used as the cellulose fiber and the mixing ratio was changed. In Example 14 (10% cotton content), wetback with milk was better. Since cotton is a fiber having a non-uniform fiber length, the number of fibers tends to be larger than that of rayon or lyocell. Therefore, in Example 14, the balance of the number of fibers of the second core-sheath type composite fiber and the cellulose fiber is better, the number of adhesion points between the second core-sheath type composite fibers is more appropriate, and the liquid residue in the second fiber layer is more. It is less likely to occur, and the adhesion point between the second core-sheath type composite fiber and the cellulosic fiber is more moderate, and the adhesion point is more moderately peeled off during liquid absorption, and the liquid residue in the second fiber layer. Is presumed to be less likely to occur.
The wetback of the physiological saline solution of Examples 14 to 16 is equal to or higher than that of Comparative Example 11 (100% second core sheath type composite fiber), and in particular, in the first wetback, Examples 14 to 16 are Comparative Example 11. It was better than. The wet back of milk loose stools of Examples 14 to 16 was improved as compared with Comparative Example 11 (100% second core sheath type composite fiber). The surface diffusivity (total) of the non-woven fabric was equal to or higher than that. It was found that the examples are suitable for loose stool diapers (especially for babies) and can also be used with napkins.
In Comparative Example 13 (cotton mixing ratio: 50%), the processability in the production of the non-woven fabric was not sufficient, and the non-woven fabric was too soft to perform the cutting process, and the fibers were likely to fall off from the cut surface. In addition, delamination between the first fiber layer and the second fiber layer was likely to occur.

For Examples 17-19 and Comparative Example 14, lyocell (1.7dtex) was used as the cellulose fiber and the mixing ratio was changed. In Example 19 (mixture ratio of lyocell: 30%), the balance between the wet back with physiological saline and milk was better, but in terms of processability in the production of the non-woven fabric and cutability of the non-woven fabric, Example 18 (of lyocell). (20% mixing ratio) was better, and overall, Example 18 (20% mixing ratio of lyocell) was better.
The wetback of Examples 17 to 19 with the saline solution was worse than that of Examples 11 to 16, but the wetback of the physiological saline solution was equivalent to that of Comparative Example 11 (100% second core sheath type composite fiber). In fact, the wet back of milk loose stool is greatly improved compared to Comparative Example 11 (second core sheath type composite fiber 100%), and the non-woven fabric surface diffusivity (total) is equal to or higher than that of Comparative Example 11, so that it can be used as a diaper for loose stool. It is considered to be more effective (especially for newborns). It can also be used as a napkin.
In Comparative Example 14 (mixture ratio of lyocell: 50%), the processability in the production of the non-woven fabric was not sufficient, and the non-woven fabric was too soft to be cut, and the fibers were likely to fall off from the cut surface. In addition, delamination between the first fiber layer and the second fiber layer was likely to occur.

[Examples 21 to 29] and [Comparative Examples 21 to 24]
For Examples 21 to 29 and Comparative Examples 21 to 24, the fibers shown in Tables 7 to 9 were used, and the same method as the method for producing the non-woven fabric of Example 1 described above was used. Nonwoven fabrics of Comparative Examples 21 to 24 were obtained.
For the non-woven fabrics of Examples 21 to 29 and Comparative Examples 21 to 24, a napkin was produced as an absorbent article, and measurement and evaluation were carried out according to the method described below. The results are shown in Tables 7-9.

The absorbability of the non-woven fabrics of Examples 21 to 29 and Comparative Examples 21 to 24 was evaluated by producing a napkin as a liquid-absorbent article for evaluation. The manufacturing method is shown below.
[Manufacturing of absorbent articles (napkins)]
A commercially available napkin (manufactured by Daio Paper Corporation, trade name Elis) consisting of a liquid absorbing part consisting of a top sheet, a second sheet, and an absorber, and a leak-proof sheet that prevents water from leaking to the outside. Megami Peel off the top sheet from the bare skin (23 cm with wings for daytime), and replace the removed top sheet with the non-woven fabrics of Examples 21 to 29 and Comparative Examples 21 to 24 (vertical 19 cm x horizontal 8 cm). ) Was laminated to obtain an absorbent article for evaluation. At the time of laminating, the first fiber layer was arranged so as to face outward, and the second fiber layer was arranged so as to face the second sheet. Using this absorbent article for evaluation, the liquid absorbency (liquid absorption time, wet back, non-woven fabric surface diffusion length) of the non-woven fabrics of Examples 21 to 29 and Comparative Examples 21 to 24 was evaluated.

[Wetback (artificial menstrual blood)]
The wet backs of the non-woven fabrics of Examples 21 to 29 and Comparative Examples 21 to 24 were evaluated by the following methods.
(1) In order to measure the amount of wet back, the following items were prepared.
Absorbent article for evaluation in the above-mentioned Examples and Comparative Examples Plates with injection cylinder (height 6.0 cm, inner diameter 2.2 cm at the top of the cylinder, inner diameter 1.0 cm at the bottom of the cylinder, two-stage cylindrical shape)
Artificial menstrual blood is adjusted to contain 100 ml of glycerin, 875 ml of ion-exchanged water, 4.6 g of CMC (sodium carboxymethyl cellulose), 10 g of NaCl (sodium chloride), and 10.7 g of Na2CO3 (sodium carbonate) in 1 liter, and a small amount is used. The one colored with edible blue No. 1 was used. (Viscosity at 37 ° C. is 8 mPa · s)
Filter paper (ADVANTEC (registered trademark) No. 2 manufactured by Toyo Filter Paper Co., Ltd.) 10 cm x 10 cm
Weight (1 kg) 10 cm x 10 cm

(2) Method The amount of wet back was measured according to the following procedure.
(I) The absorbent article for evaluation was arranged so that the non-woven fabric (vertical 19 cm × horizontal 8 cm) faced upward, and a plate with an injection tube was placed on it.
(Ii) 5.0 ml of artificial menstrual blood warmed to about 37 ° C. was injected from a cylinder. It was left until the artificial menstrual blood disappeared from the surface of the non-woven fabric (the artificial menstrual blood was not confirmed as a liquid).
(Iii) The plate with the injection tube was removed and allowed to stand for 10 minutes.
(Iv) A filter paper (10 sheets) whose mass was measured in advance was placed on a non-woven fabric, and a 1 kg weight was placed on the filter paper for 20 seconds. Then, the mass of the filter paper was measured. The difference between the mass of the filter paper before being placed on the non-woven fabric and the mass of the filter paper after being placed on the non-woven fabric and further placing the weight corresponds to the amount of wet back.
(V) Returning to (i) above, (i) to (iv) were repeated to perform another measurement. Wetback was evaluated twice in total.
Three samples were prepared for one sample (nonwoven fabric). The average value of the wetback amount measured for each of the three samples was taken as the wetback amount of the sample.

[Liquid absorption time (artificial menstrual blood)]
In the wetback measurement, the liquid absorption time was measured at the time of the first measurement and the second measurement, respectively. The liquid absorption time was measured by measuring the time during which the artificial menstrual blood disappeared from the surface of the non-woven fabric (the artificial menstrual blood was not confirmed as a liquid) from the injection of the artificial menstrual blood, and used as the liquid absorption time.

Examples 21 to 29 correspond to Examples 11 to 19 respectively, and Comparative Examples 21 to 24 correspond to Comparative Examples 11 to 14, respectively. Since Examples 21 to 29 are napkins and Examples 11 to 19 are diapers, they are different as absorbent articles, but Examples 21 to 29 have the same tendency as those of Examples 11 to 19 described above. Indicated.

Among Examples 21 to 23, in Example 23 (mixing ratio of rayon D: 30%), the balance between the liquid absorption time and the wet back was better. Among Examples 24 to 26, in Example 25 (cotton mixing ratio 20%), the balance between the liquid absorption time and the wet back was better. Among Examples 27 to 29, in Example 28 (mixture ratio of lyocell 20%), the balance between the liquid absorption time and the wet back was better. In Examples 23, 25, and 28, the balance between the number of fibers of the second core-sheath type composite fiber and the number of cellulose fibers is better, so that the number of adhesion points between the second core-sheath type composite fibers is more appropriate. Liquid residue in the second fiber layer is less likely to occur, and the adhesion point between the second core-sheath type composite fiber and the cellulosic fiber is more appropriate, and the adhesion point is more appropriate during liquid absorption. It is presumed that the peeling caused the liquid residue in the second fiber layer to be less likely to occur. In particular, since artificial menstrual blood has a high viscosity, it is considered that the effect of further reducing the liquid residue is large.

The non-woven fabric for absorbent articles of the embodiment of the present invention can further improve the absorbency of fluids such as loose stools while maintaining the liquid absorption performance and the tactile sensation. Therefore, the non-woven fabric for absorbent articles of the embodiment of the present invention can be suitably used for producing a top sheet and an absorbent article.

Claims (10)

A non-woven fabric containing a first fiber layer and a second fiber layer located on one main surface of the first fiber layer.
The first fiber layer contains a first core-sheath type composite fiber and contains.
The second fiber layer contains a second core-sheath type composite fiber and a cellulosic fiber.
The fineness of the first core-sheath type composite fiber is smaller than the fineness of the second core-sheath type composite fiber.
The fineness of the first core-sheath type composite fiber is 1.0 to 2.8 dtex.
The fineness of the second core-sheath type composite fiber is 1.7 to 5.6 dtex.
The fineness of the cellulosic fiber is 1.2 to 6.0 dtex.
The second fiber layer contains the cellulosic fiber at a ratio of 5% by mass to 40% by mass based on the total mass of the second fiber layer.
Non-woven fabric for absorbent articles. The nonwoven fabric for absorbent articles according to claim 1, wherein the second fiber layer contains the cellulosic fibers in a proportion of 15% by mass to 25% by mass based on the total mass of the second fiber layer. The non-woven fabric for an absorbent article according to claim 1 or 2, wherein the cellulosic fiber contains viscose rayon. The non-woven fabric for an absorbent article according to any one of claims 1 to 3, wherein the basis weight of the first fiber layer is smaller than the basis weight of the second fiber layer. The non-woven fabric for an absorbent article according to any one of claims 1 to 4, wherein the absorbent article includes an absorbent article for absorbing a fluid containing water and oil. The non-woven fabric for an absorbent article according to claim 5, wherein the fluid containing water and oil contains loose stool. A top sheet for absorbent articles, which comprises the non-woven fabric for absorbent articles according to any one of claims 1 to 6. The first fiber layer of the top sheet for an absorbent article according to claim 7 is arranged on the side close to the skin of the user, and the absorbent article including the top sheet for an absorbent article according to claim 7. .. The absorbent article according to claim 8, which comprises an absorbent article for absorbing a fluid containing water and oil. The absorbent article according to claim 9, wherein the fluid containing water and oil contains loose stool.