JP2014121489A - Absorption assisting sheet and absorber using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an absorption assisting sheet having excellent absorption performance and biodegradability, and to provide an absorber.SOLUTION: The absorption assisting sheet is superposed on a liquid absorbent sheet having water absorbability or liquid absorbability of low-viscosity liquid, and assists the liquid absorbent sheet by retaining high-viscosity liquid having absorption which is hard for the liquid absorbent sheet. The absorption assisting sheet comprises at least one-layer nonwoven fabric that is formed by heat-treating air-laid web consisting of a material fiber that contains at least one type of thermally fusible fiber (S) selected from a fiber (x1) and a fiber (x2) and has a content of not less than 2 mass% and not more than 50 mass%. The nonwoven fabric has a basis weight of 50 g/g/mor more, and apparent density of not less than 0.015 g/cmand not more than 0.045 g/cm. The fiber (x1) is a thermally fusible fiber composed of a resin (A) selected from polybutylene succinate. The fiber (x2) is a thermally fusible fiber composed of a resin (B) selected from polylactic acid and the resin (A).

Description

  The present invention relates to an absorption assisting sheet and an absorbent body having the same.

Absorbers that absorb and hold liquids are used in various applications. For example, many absorbent articles such as volatilizers for body fluids, excrement, food drip, oil absorption, osboli, waste ink, cosmetics, liquid fragrances, repellents, etc. Is provided with a sheet-like absorber. As the absorbent sheet, for example, a nonwoven fabric made of pulp fiber or hydrophilic resin fiber, a hydrophilic resin sheet, or the like is used.
The absorbent sheet is required to have liquid retention properties that retain absorbed liquid, particularly moisture. However, an absorbent sheet having a high liquid retention property has a property of retaining itself without allowing liquid to permeate, and therefore, the liquid absorption rate tends to be slow, and the amount of liquid remaining on the surface of the absorbent sheet is usually high. If the liquid remains on the surface of the absorbent sheet, an object to be absorbed leaks out of the absorbent article, or a portion in contact with the absorbent article becomes dirty. Therefore, in the absorbent article, an absorption auxiliary sheet having higher permeability than the absorbent sheet is disposed on the absorbent sheet. The liquid in contact with the absorption assisting sheet of such an absorbent article quickly passes through the absorption assisting sheet and moves below the surface, and is then absorbed by the absorber. This method is effective when the object to be absorbed is a low viscosity liquid such as urine. However, excretion such as a food containing a high-viscosity liquid or solid content, for example, candy-like food, creamy cosmetics, loose stool, mud stool, etc. tends to remain on the absorption assisting sheet.

  Various studies have been made to further improve the absorbability of the absorbent body and absorbent articles. For example, Patent Document 1 discloses at least a base layer composed of a dry nonwoven web or mat mainly composed of natural cellulose fibers as an ink absorber that can smoothly penetrate and diffuse even with high viscosity and concentration inks. It describes what laminated a bulky synthetic fiber sheet layer having a specific density and thickness on one side. Patent Document 2 describes an absorbent product including a distribution unit that distributes liquid discharged from a wearer of the absorbent product to the surface of the absorbent body. In Patent Document 3, as an absorbent article that can keep soft stool away from the skin promptly, and securely house and hold the soft stool at a position far from the skin, a surface sheet that transmits excrement, a transmission sheet that transmits excrement, and The thing provided in order with the absorption element containing the cotton-like pulp which hold | maintains excrement is described. In Patent Document 4, as an absorbent article that is excellent in diffusivity in the surface direction of urine and the like and can quickly absorb urine and the like, a liquid-permeable absorption auxiliary sheet, a liquid-impermeable back sheet, and these What has the absorptive laminated body of the specific structure provided between is described.

  In recent years, biodegradability has been required for absorbent articles such as disposable diapers and sanitary napkins. In particular, those having water decomposability that decomposes when in contact with a large amount of water have been studied in various ways because they have the advantage that they can be directly discarded in a flush toilet. For example, Patent Document 5 discloses a liquid-permeable surface sheet that appears on the skin-side surface and a water-decomposable back surface that appears on the clothing-side surface as an absorbent article having good water-disintegrating properties and excellent liquid-absorbing and leak-proofing properties. And a sheet using a specific water-decomposable nonwoven fabric as the top sheet.

JP 2000-135797 A JP 2002-238946 A JP 2007-097643 A JP 2012-24206 A JP 2004-344443 A

When the object to be absorbed has a high viscosity, for example, when it contains a high-viscosity liquid or solid content, for improving the absorption performance, the permeability can be quickly transmitted through the object having a high viscosity and absorbed under the surface. In addition, it is necessary to improve both the liquid retention properties that can sufficiently retain the liquid contained in the absorbed object to be absorbed. In addition, by suppressing the reversal of the object to be absorbed, and by providing an absorption assisting sheet on the surface in contact with the object to be absorbed so that the object having high viscosity does not remain on the surface of the absorber, It is necessary to promptly take up an object to be absorbed having a high viscosity into the absorbent body.
However, it cannot be said that conventional absorbers and absorbent articles sufficiently satisfy this characteristic. In particular, in the case of biodegradable absorbers and absorbent articles, especially water-degradable absorbers and absorbent articles, the raw materials that can be used are limited, and the techniques that can be applied to improve water absorption performance are also limited. The
Therefore, a technology that can achieve both excellent absorption performance that can be quickly absorbed and retained even for high viscosity objects and excellent biodegradability that can be used as a water-degradable absorber or absorbent article. Is required.

  This invention is made | formed in view of the said situation, and aims at providing the absorption auxiliary sheet and absorber which have the outstanding absorption performance and biodegradability.

The present invention for solving the above problems has the following aspects.
[1]
Liquid-absorbing aid that assists the liquid-absorbing sheet by holding a high-viscosity liquid that is difficult to absorb with the liquid-absorbing sheet, overlaid on a liquid-absorbing sheet that absorbs water or absorbs low-viscosity liquids A sheet,
An airlaid web comprising raw fibers containing a content of at least one heat-fusible fiber (X) selected from the following fibers (x1) and the following fibers (x2) from 2% by mass to 50% by mass absorbent auxiliary sheet basis weight of heat treated consists 50 g / ^{m 2} or more at least one layer of nonwoven fabric, and an apparent density equal to or less than 0.015 g / cm ³ or more 0.045 g / cm ^3.

Fiber (x1): polybutylene succinate, poly (hydroxybutyrate / hydroxyhexanoate), polycaprolactone, poly (caprolactone / butylene succinate), poly (butylene succinate / adipate), poly (butylene succinate / carbonate) ), Poly (butylene adipate / terephthalate) and polyethylene succinate, a heat-fusible fiber comprising at least one resin (A).
Fiber (x2): a heat-fusible fiber comprising at least one resin (B) selected from polylactic acid, polyhydroxybutyrate, polyglycolic acid and cellulose acetate, and the resin (A).

[2]
Of the thickness of the absorption assisting sheet, the apparent density of the surface side half in contact with the liquid is 0.03 g / cm 3 or more, and the apparent density of the opposite side half is smaller than the apparent density of the surface side half [1] Absorption auxiliary sheet.
[3]
The absorption auxiliary sheet according to [1], wherein the apparent density of the front half in contact with the liquid is smaller than the apparent density of the rear half in the thickness of the absorption auxiliary sheet.
[4]
The absorption assisting sheet according to any one of [1] to [3], wherein the raw fiber further contains a high melting point fiber (Y) made of the resin (B).
[5]
The absorption assisting sheet according to any one of [1] to [4], wherein the raw fiber further includes a latent crimpable conjugate fiber (Z) made of the following resin (B) and having a hollow portion.

[6]
The absorption assisting sheet according to any one of [1] to [5], wherein the raw fiber further contains a polyvinyl alcohol resin fiber.
[7]
The content of the heat-fusible fiber (X) in the raw fiber is 2% by mass or more and 50% by mass or less, and the content of the polyvinyl alcohol resin fiber is the content of the heat-fusible fiber (X). The absorption assisting sheet according to any one of [1] to [6], which is 50% by mass or more based on the amount.
[8]
The absorption assisting sheet according to any one of [1] to [7], wherein the absorption assisting sheet has a thickness of 3 mm to 40 mm.
[9]
The absorbent auxiliary sheet according to any one of [1] to [8], on an absorbent layer made of a nonwoven fabric obtained by heat-treating an air-laid web composed of raw material fibers having a cellulose fiber content of 5% by mass to 98% by mass Absorber with laminated layers.

  ADVANTAGE OF THE INVENTION According to this invention, the absorption auxiliary sheet and absorber which have the outstanding high viscosity absorption performance and biodegradability can be provided.

It is a schematic longitudinal cross-sectional view explaining the structure of the absorption auxiliary sheet 10 which concerns on 1st embodiment of this invention. It is a schematic longitudinal cross-sectional view explaining the structure of the absorption auxiliary sheet 20 which concerns on 2nd embodiment of this invention. It is a schematic longitudinal cross-sectional view explaining the structure of the absorption auxiliary sheet 30 which concerns on 3rd embodiment of this invention. It is a schematic longitudinal cross-sectional view explaining the structure of the absorber 40 which concerns on 4th embodiment of this invention.

  Hereinafter, the present invention will be described with reference to the accompanying drawings.

<First embodiment>
FIG. 1 is a schematic longitudinal sectional view illustrating the configuration of an absorption assisting sheet 10 according to the first embodiment of the present invention.
The absorption auxiliary sheet 10 is made of a non-woven fabric obtained by heat-treating an air-laid web composed of raw fibers containing a heat-fusible fiber (X) content of 2 mass% or more and 50 mass% or less.
The absorption auxiliary sheet 10 is superposed on a liquid absorbent sheet having water absorbency or liquid absorbency to a low viscosity liquid, and holds a liquid of a high viscosity object to be absorbed that is difficult to absorb with the liquid absorbent sheet. A liquid-absorbing sheet can be assisted. The absorbent object is used so as to first contact the surface of the auxiliary absorption sheet 10.

As a manufacturing method of a nonwoven fabric, the method of passing through the web formation process which forms a sheet-like web from raw material fiber, and the fiber joint process which couple | bonds the raw material fiber in the obtained web is common. The “non-woven fabric obtained by heat-treating the air-laid web” is formed by forming a web (air-laid web) by the air-laid method in the web forming step and bonding the raw fibers by the thermal bond method in the fiber bonding step. The airlaid method is a method of forming a web by randomly laminating raw material fibers three-dimensionally using an air flow. The thermal bond method is a method in which a heat treatment is performed on a web to melt a heat-fusible component (resin (A) in the present embodiment) in the web to form a bond between raw fibers. By combining the airlaid method and the thermal bond method, it is possible to obtain a non-woven fabric excellent in absorption performance as compared with other methods.
For example, as a web forming method, there is a carding method in which a fiber card is mechanically wound using a roller card machine (carding machine), and a sheet-like web is formed from raw fibers having a long fiber length. The carding method is the same dry method as the airlaid method, but even if the resulting nonwoven fabric has the same density and thickness, the nonwoven fabric formed from the airlaid web has better absorption performance and a high viscosity absorbent object Even so, it can be quickly absorbed and retained.
This is thought to be due to the following reasons. That is, the air laid method is a method of forming a web in which raw fiber having a short fiber length is laminated using an air flow, and therefore the raw fiber is randomly oriented three-dimensionally in the obtained air laid web. By applying the thermal bond method to such a web, it is considered that a large number of voids suitable for absorbing and holding a high-viscosity absorbent object are formed in the obtained airlaid web. On the other hand, for example, when the web is formed by a carding method, the fibers are oriented almost two-dimensionally in the obtained card web.

As described above, the nonwoven fabric combining the airlaid method and the thermal bond method can be obtained with a small apparent density and a large number of voids. It has excellent permeability that can be quickly transmitted and absorbed under the surface, and the low-viscosity absorption target can be directly permeated below and absorbed by the absorbent layer or the absorbent sheet disposed below. Suitable for use as an absorption auxiliary sheet. In the present embodiment, an apparent density of 0.015 g / cm ³ or more 0.045 g / cm ³ or less of the adjusted basis weight 50 g / ^{m 2} or more air-laid nonwoven fabric in the range. Further, the absorption assisting sheet of the present invention composed of raw fiber containing 2% by mass or more and 50% by mass or less of the heat-fusible fiber (X) is excellent in shape retention, for example, an object to be absorbed Loss of shape such as thickness reduction due to its own weight. Therefore, even in a nonwoven fabric combining the airlaid method and the thermal bond method with a particularly low apparent density as in the present invention, the permeation / absorption capacity of the object to be absorbed is hardly reduced due to a decrease in thickness or the like. That is, the nonwoven fabric of the present invention functions as an excellent absorption assisting sheet by having the above-described features.
Furthermore, the absorption assisting sheet of the present invention has water decomposability. Moreover, the raw material fiber of the present invention contains a certain amount or more of fibers made of biodegradable materials (resin (A), resin (B)). Therefore, the absorption assisting sheet of the present invention is excellent in biodegradability. Therefore, the absorption assisting sheet 10 can be disposed of after use by a simple method such as flowing in a flush toilet or buried in soil, and decomposes in a short period of time even if buried in the soil and discarded.

{Absorption auxiliary sheet 10}
The absorption assisting sheet 10 is derived from an airlaid web composed of the following raw material fibers.
The raw material fiber has a content of at least one heat-fusible fiber (X) selected from the following fibers (x1) and the following fibers (x2) from 2% by mass to 50% by mass. In addition, each content is a ratio with respect to the total amount (100 mass%) of raw material fibers.
Fiber (x1): polybutylene succinate, poly (hydroxybutyrate / hydroxyhexanoate), polycaprolactone, poly (caprolactone / butylene succinate), poly (butylene succinate / adipate), poly (butylene succinate / carbonate) ), Poly (butylene adipate / terephthalate) and polyethylene succinate, a heat-fusible fiber comprising at least one resin (A).
Fiber (x2): a heat-fusible fiber comprising at least one resin (B) selected from polylactic acid, polyhydroxybutyrate, polyglycolic acid and cellulose acetate, and the resin (A).

Resin (A) is a resin having a relatively low melting point, and functions as a heat-fusible component in a fiber bonding step by a thermal bond method. Therefore, the heat-fusible fiber (X) containing the resin (A) contributes to improving the shape retention of the absorption assisting sheet 10.
The absorption assisting sheet 10 is bulky because it is formed by the airlaid method as described above. When 2 mass% or more of heat-fusible fibers (X) are contained in the raw material fibers, there are sufficient binding points between the raw material fibers in the air-laid web to be formed, and shape retention is improved. Moreover, the moisture content (water retention) in the absorption auxiliary sheet 10 is lowered by not including many fibers having high hydrophilicity. Therefore, the formed absorption assisting sheet 10 is bulky, has a low density, and does not easily lose its shape, and exhibits excellent permeability with respect to an object to be absorbed having a high viscosity.

However, when only the heat-fusible fiber (X) is used as the raw material fiber of the absorption assisting sheet 10, the permeability is excellent, but the water decomposability cannot be obtained. If the content of the heat-fusible fiber (X) in the raw fiber of the absorption assisting sheet is 50% by mass or less, water decomposability is obtained.
From the viewpoint of water decomposability, it is preferable that the raw fiber of the absorption assisting sheet 10 further contains a high melting point fiber (Y) made of the resin (B) in addition to the heat-fusible fiber (X). Thereby, since the ratio of heat-fusible fiber (X) becomes comparatively low and the binding point of the raw material fibers in the absorption auxiliary sheet 10 decreases, the water disintegration property of the absorption auxiliary sheet 10 improves.
From the viewpoint of water disintegration, the raw material fiber of the absorption assisting sheet 10 is added to the heat-fusible fiber (X), or to the heat-fusible fiber (X) and the high-melting fiber (Y), and further, polyvinyl. It is preferable to contain alcohol resin fibers (hereinafter referred to as PVA fibers). By combining PVA fibers, which are water-soluble fibers, when the PVA fibers are in contact with a large amount of water, the binding points between the raw fibers in the absorption assisting sheet 10 are reduced, and the absorption assisting sheet 10 Decomposes (hydrolysis). In addition, biodegradability is improved because it is easy to decompose when processing such as burying in soil.

[Heat-bondable fiber (X)]
Commercially available fibers (x1) and fibers (x2) can be used as the heat-fusible fibers (X). Moreover, you may use what was manufactured by the well-known manufacturing method.
Here, the “heat-sealable fiber” refers to a material fiber that can be heat-sealable by heat treatment because at least a part of the material fiber constituting the fiber group is a heat-sealable component.
Both the fiber (x1) and the fiber (x2) have the resin (A) as a heat-fusible component.
The fiber (x1) is made of the resin (A), part or all of which is melted by heat treatment, and the melted part acts as a binder for fusing the surfaces of the raw fiber.
The fiber (x2) is composed of the resin (A) and the resin (B), and a part or all of the portion (for example, the sheath portion of the core-sheath structure) composed of the resin (A) is melted by heat treatment. The melted part acts as a binder.

Resin (A) is polybutylene succinate, poly (hydroxybutyrate / hydroxyhexanoate), polycaprolactone, poly (caprolactone / butylene succinate), poly (butylene succinate / adipate), poly (butylene succinate / Carbonate), poly (butylene adipate / terephthalate) and at least one selected from polyethylene succinate. Resin (A) is excellent in biodegradability and has a melting point of 60 to 165 ° C. suitable for fusing in a fiber bonding step by a thermal bond method. It is preferable that melting | fusing point of resin (A) is 100-165 degreeC.
The resin (B) is at least one selected from polylactic acid, polyhydroxybutyrate, polyglycolic acid, and cellulose acetate. Resin (B) is excellent in biodegradability and has a melting point of 170 ° C. or higher suitable for maintaining the fiber form without melting in the fiber bonding step by the thermal bond method. The melting point of the resin (B) is preferably 170 to 250 ° C.
In the present specification, the melting point of the resin is a value measured by a micro melting point measuring method DSC (scanning calorimeter) or the like.

As fiber (x1), if it consists of resin (A), it will not specifically limit, A commercially available thing can be used. Moreover, you may use what was manufactured by the well-known manufacturing method.
The resin (A) constituting the fiber (x1) may be one type or two or more types.
When the resin (A) constituting the fiber (x1) is two or more kinds, the fiber (x1) may be composed of a mixture of two or more kinds of resins (A), or two or more kinds of resins ( A composite synthetic fiber obtained by combining A) may be used. Examples of the composite synthetic fiber include a synthetic fiber having a side-by-side structure obtained by combining two different types of resins (A), a synthetic fiber having a core-sheath structure, and the like. The core-sheath structure may be a concentric core-sheath structure or an eccentric core-sheath structure.

The fiber (x2) is not particularly limited as long as it is made of the resin (A) and the resin (B) and at least a part of the fiber surface is made of the resin (A), and a commercially available product can be used. Moreover, you may use what was manufactured by the well-known manufacturing method.
The resin (A) and the resin (B) constituting the fiber (x2) may each be one type or two or more types.
Examples of the fiber (x2) include a synthetic fiber having a side-by-side structure obtained by combining the resin (A) and the resin (B), a synthetic fiber having a core-sheath structure, and the like. In the case of the core-sheath structure, the resin (A) constitutes the sheath part, and the resin (B) constitutes the core part. The core-sheath structure may be a concentric core-sheath structure or an eccentric core-sheath structure.
The mass ratio of the resin (A) to the resin (B) in the fiber (x2) (for example, the core-sheath composite ratio in the core-sheath structure) is resin (A) / resin (B) = 2/8 to 8/2. 4/6 to 6/4 is more preferable.

The fibers (x2) may be latent crimped synthetic fibers.
Latent crimped synthetic fiber is a synthetic fiber in which crimps (crimp, curl, spiral) are manifested by heat. When crimping becomes apparent when the air-laid web is heat-treated, the air-laid web becomes more bulky.
Examples of latent crimped synthetic fibers used as the fibers (x2) include, for example, synthetic fibers having a side-by-side structure obtained by combining the resin (A) and the resin (B), and synthetic fibers having an eccentric core-sheath structure. Is mentioned.
The latent crimped synthetic fiber may have mild crimps in advance or may not have.

  In the raw fiber, the fiber length of the heat-fusible fiber (X) (fiber (x1), fiber (x2)) is preferably 2 to 20 mm, more preferably 2 to 10 mm, and further preferably 2 to 6 mm. With such a fiber length, when forming an air laid web, these fibers are three-dimensionally laminated at random, and as a result, the first region 1 is bulky and has a high viscosity for an object to be absorbed. However, it tends to exhibit excellent permeability. Moreover, it becomes difficult to lose shape. On the other hand, if the fiber length is less than the lower limit of this range, the fibers become dense in the absorption assisting sheet, and the permeability may be lowered. Moreover, when touching the skin with the absorption assisting sheet, there is a concern that the touch becomes hard and a feeling of tingling occurs.

  The fiber diameter of the heat-fusible fiber (X) is preferably 0.5 to 74 dtex, more preferably 0.8 to 35 dtex, and still more preferably 1.0 to 20 dtex. When the fiber diameter is such, the absorption assisting sheet is likely to be bulky and to exhibit excellent permeability even for an object to be absorbed having a high viscosity. Moreover, it is excellent also in the touch. On the other hand, when the fiber diameter is less than the lower limit of this range, the touch is good, but the gap size is small, the resistance when absorbing a high viscosity object is increased, and the permeability is poor. Tend. If the fiber diameter exceeds the upper limit of this range, the fiber itself becomes stiff and the tingling sensation increases and the touch tends to deteriorate.

In this specification, the fiber length of the raw fiber is an average value of lengths measured by observation with an electron microscope using 50 or more arbitrarily selected fibers as samples.
The fiber diameter of the raw fiber is represented by the unit “dtex (decitex)”. 1 dtex is the thickness of a thread having a length of 10,000 m and a weight of 1 g.

  As the heat-fusible fiber (X), one type may be used alone, or two or more types may be used in combination. For example, the fiber (x1) and the fiber (x2) may be used in combination, two or more types may be used in combination as the fiber (x1), and two or more types may be used in combination as the fiber (x2).

Among the above, the heat-fusible fiber (X) preferably contains the fiber (x2). The resin (B) is a resin having a higher melting point than the resin (A), and does not melt at a normal heat treatment temperature in the thermal bond method. The higher the ratio of the fiber (x2) containing the resin (B) in the heat-fusible fiber (X), the more easily the bulk of the resulting absorption assisting sheet tends to be higher, and the tendency to be excellent in the permeability of a high-viscosity absorbent object. is there.
It is preferable to use latent crimped synthetic fibers as the fibers (x2) because they tend to be more bulky and excellent in the absorbability of an object to be absorbed having a high viscosity.

The ratio of the heat-fusible fiber (X) in the first raw fiber is 2% by mass or more and 50% by mass or less. When the proportion of the heat-fusible fiber (X) is 2% by mass or more, the shape retention is sufficiently improved and excellent permeability is exhibited. Water decomposability and biodegradability are improved when the content is 50% by mass or less.
The content of the heat-fusible fiber (X) in the raw fiber is preferably 5% by mass or more from the viewpoint of shape retention and permeability, and preferably 30% by mass or less from the viewpoint of water decomposability and biodegradability. 20 mass% or less is more preferable.
However, when the content of the heat-fusible fiber (X) in the raw fiber is 10% by mass or more, in order to obtain sufficient water decomposability, it is preferable that the raw fiber further contains a PVA fiber. .
Considering these, when the raw fiber does not contain PVA fiber, the content of the heat-fusible fiber (X) in the raw fiber is more preferably 2% by mass or more and 10% by mass or less, and more preferably 5% by mass or more and 8% by mass. A mass% or less is particularly preferred.
When the raw fiber includes PVA fiber, the content of the heat-fusible fiber (X) in the raw fiber is not particularly limited as long as it is in the range of 2% by mass to 50% by mass, but 10% by mass or more. 50 mass% or less is preferable, 10 mass% or more and 30 mass% or less are more preferable, and 10 mass% or more and 20 mass% or less are especially preferable.
When the content of the heat-fusible fiber (X) in the raw material fiber is 10% by mass or more and 50% by mass or less, the content of the PVA fiber in the raw material fiber is the content of the heat-fusible fiber (X). It is preferable that it is 50 mass% or more with respect to it, and it is more preferable that it is 100-200 mass%.

[High melting point fiber (Y)]
The high melting point fiber (Y) is a fiber made of the resin (B).
As high melting point fiber (Y), if it consists of resin (B), it will not specifically limit, A commercially available thing can be used. Moreover, you may use what was manufactured by the well-known manufacturing method.
The resin (B) constituting the high melting point fiber (Y) may be one type or two or more types.
When the resin (B) constituting the high melting point fiber (Y) is two or more kinds, the high melting point fiber (Y) may be composed of a mixture of two or more kinds of resins (B). The composite synthetic fiber which compounded the above resin (B) may be sufficient. Examples of the composite synthetic fiber include a synthetic fiber having a side-by-side structure obtained by combining two different types of resins (B), a synthetic fiber having a core-sheath structure, and the like. The core-sheath structure may be a concentric core-sheath structure or an eccentric core-sheath structure.
Like the heat-fusible fiber (X), the fiber length of the high melting point fiber (Y) is preferably 2 to 20 mm, more preferably 2 to 10 mm, and further preferably 2 to 6 mm.
The fiber diameter of the high melting point fiber (Y) is preferably 0.5 to 74 dtex, more preferably 0.8 to 35 dtex, and even more preferably 1.0 to 20 dtex, like the heat-fusible fiber (X).
As high melting point fiber (Y), 1 type may be used independently or 2 or more types may be used together.
0-93 mass% is preferable, as for the ratio of the high melting point fiber (Y) in a 1st raw material fiber, 0-90 mass% is more preferable, and 40-88 mass% is further more preferable.

[Latent crimped fiber (Z) having a hollow portion]
The raw fiber includes a composite fiber made of at least one resin (B) selected from polylactic acid, polyhydroxybutyrate, polyglycolic acid, and cellulose acetate, and having a hollow portion. Since this composite fiber has a hollow portion, the basis weight of the first web can be reduced, cushioning properties can be imparted, and as a result, the rigidity of the absorption assisting sheet of the present invention can be reduced. . Further, the composite fiber is a latent crimp synthetic fiber in which crimps (crimp, curl, spiral) are manifested by heat. When the air-laid web is heat-treated, the absorption assisting sheet of the present invention becomes more bulky because the crimps become obvious. As the average fineness of the composite fiber, one having a range of 5 to 50 dtex can be used. When the average fineness of the composite fiber is less than 5 dtex, the gap between the fibers constituting the absorption assisting sheet formed becomes small, and the liquid to be absorbed is less likely to quickly permeate through the web, and the surface to be absorbed is absorbed on the surface of the absorbent sheet. Since the diffusion area of the absorption object seen from the absorption surface side cannot be reduced so that no object remains, it is not preferable. On the other hand, when it exceeds 50 dtex, since the rough fiber is contained on the surface of the absorption assisting sheet, the feel is inferior, which is not preferable.
Latent formed of at least one resin (B) selected from polylactic acid, polyhydroxybutyrate, polyglycolic acid and cellulose acetate contained in the raw fiber and having an average fineness of 5 to 50 dtex having hollow portions The amount of the crimpable fiber is preferably 0.15% by mass or more and 95% by mass or less, and more preferably 5% by mass or more and 90% by mass or less. If it is less than 0.15% by mass, it is not preferable because sufficient effect for imparting bulkiness is not recognized, and if it exceeds 95% by mass, there are few adhesion points between fibers in the absorption assisting sheet, so that sufficient adhesion is achieved. Cannot be obtained, and the form cannot be maintained as a sheet.
As the latent crimpable fiber (Z) having a hollow part used in the present invention, for example, a hollow composite fiber in which resins (B) having different heat shrinkability are arranged in a side-by-side manner can be exemplified. In particular, a composite fiber having an average fineness of 5 to 50 dtex having a polylactic acid resin having a different molecular weight arranged in a side-by-side manner and having a hollow portion can be preferably used.

[PVA fiber]
A PVA fiber will not be specifically limited if it melt | dissolves when it contacts with a lot of water, A commercially available thing can be used. Moreover, you may use what was manufactured by the well-known manufacturing method.
As a polyvinyl alcohol resin which comprises PVA fiber, what satisfy | fills JIS standard K6950 (ISO14885) of a biodegradable plastic is desirable.
Like the heat-fusible fiber (X), the fiber length of the PVA fiber is preferably 2 to 20 mm, more preferably 2 to 10 mm, and further preferably 2 to 6 mm.
The fiber diameter of the PVA fiber is preferably 0.5 to 74 dtex, more preferably 0.8 to 35 dtex, and even more preferably 1.0 to 20 dtex, like the heat-fusible fiber (X).

  The content of the PVA fiber in the raw fiber is preferably 2% by mass or more and 95% by mass or less, more preferably 5 to 50% by mass, and further preferably 7 to 30% by mass. When the proportion of the PVA fiber is 2% by mass or more, water decomposability and biodegradability are improved. When the content is 95% by mass or less, the transparency is improved.

  When the content of the heat-fusible fiber (X) in the raw material fiber is 10% by mass or more and 50% by mass or less, the content of the PVA fiber in the raw material fiber is as follows. It is preferable that it is 50 mass% or more with respect to content of fiber (X), and it is more preferable that it is 100-200 mass%.

[Any raw fiber]
The raw fiber may contain fibers other than the heat-fusible fiber (X), the high-melting point fiber (Y), and the PVA resin fiber.
The other fiber may be any fiber that does not impair the biodegradability of the absorption assisting sheet. Examples thereof include cellulosic fibers (pulp, rayon, cupra, cotton, etc.), natural fibers, and the like. However, if the cellulose fiber content is too large, the permeability of the absorption assisting sheet may be impaired. Therefore, the ratio of the cellulose fiber in raw material fiber is less than 5 mass%, 3 mass% or less is preferable and 2 mass% or less is more preferable.

As a raw material fiber, what is necessary is just to contain 5 mass% or more and 50 mass% or less of heat-fusible fiber (X), and also contains any one or both of a high melting point fiber (Y) and a PVA fiber. Those that do are preferred.
Especially, it is preferable that it is the following raw material fiber (I-1) or (I-2) at the point from which the absorption auxiliary sheet excellent in water disintegration is obtained.
Raw material fiber (I-1): The total amount of the high melting point fiber (Y) and the PVA fiber is 80% by mass or more (preferably 90% by mass or more), and the content of the heat-fusible fiber (X) is 2 Raw material fibers that are not less than 20% by mass and not more than 20% by mass (more preferably not less than 2% by mass and not more than 10% by mass).
Raw material fiber (I-2): The content of the heat-fusible fiber (X) is 10% by mass or more and 50% by mass or less, and the content of the PVA fiber is the content of the heat-fusible fiber (X). The raw fiber which is 50 mass% or more (preferably 100 mass% or more).
It is particularly preferable that the raw fibers (I-1) and (I-2) each have a total amount of 100% by mass of the high melting point fiber (Y), the PVA fiber, and the heat-fusible fiber (X). .

An absorption auxiliary sheet may be comprised only from said raw material fiber, and may contain other components other than raw material fiber in the range which does not impair the effect of this invention as needed.
As the other component, a known additive can be used as an additive in the absorption assisting sheet without particular limitation, and examples thereof include functional powder, functional fiber, and functional liquid.
As the functional powder and functional fiber, those having any one or more of deodorizing function, antibacterial function, antiviral function, antiallergen function, antifungal function, aroma function, functional liquid and the like are preferable. For example, zeolite, activated carbon, chitin, chitosan, scallop shell, titanium oxide, titanium dioxide, magnesium oxide, plant extract, mushroom extract, catechin, flavonol, cyclodextrin, collagen fiber, iron oxide, citric acid, zinc pyrithione, hinokitiol, Examples include eucalyptus extract.

The basis weight of the absorption assisting sheet of the present invention is 50 g / m ² or more. Since the absorption assisting sheet of the present invention can be overlapped to form one absorption assisting sheet according to the amount of the target object having a high viscosity to be absorbed, the upper limit of the basis weight is not particularly limited. but is preferably 1200 g / ^{m 2} or less from the handling property such as when attached use on the human body or the like, and more preferably 100 to 1000 g / ^{m 2.} More preferably, it is 200-800 g / m < ² >. When the basis weight of the absorption assisting sheet is equal to or more than the lower limit of the above range, the object to be absorbed with high viscosity is retained and functions as an absorption assisting sheet. When the basis weight of the absorption assisting sheet is equal to or less than the upper limit of the above range, the feeling of wearing, handling and productivity of the absorption assisting sheet are good.

The absorption assisting sheet of the present invention has an apparent density of 0.015 to 0.045 g / cm ³ , and more preferably 0.02 to 0.045 g / cm ³ . When the density exceeds the upper limit of the above range, there are few voids, or the size of the voids is too small, and the permeability of the high-viscosity absorption object may be insufficient. In addition, the feeling of use becomes worse. If the density is less than the lower limit of the above range, there will be too many voids in the absorption assisting sheet or the size of the voids will be too large. The absorption assisting sheet may be crushed to significantly reduce the absorbency, and even if the object to be absorbed is once absorbed, it is difficult to hold and there is a risk of reversal.

  The thickness of the absorption assisting sheet 10 is preferably 3 to 40 mm, more preferably 6 to 30 mm, and still more preferably 8 to 20 mm. When the thickness of the absorption assisting sheet 10 is small, there may be a case where a capacity for sufficiently holding the high viscosity object to be absorbed is not obtained. In the case of wearing, there is a problem that the feeling of wearing becomes worse. The absorption assisting sheet 10 can be made to have the above thickness by laminating a thinner non-woven fabric. Moreover, in that case, the nonwoven fabrics constituting the absorption assisting sheet are not necessarily bonded to each other. In addition, the absorption assisting sheet can be used by being superimposed on at least the surface of the absorber including the absorption layer, but in this case also, the absorber and the absorption assisting sheet 10 need not necessarily be bonded and integrated with each other. Absent.

  In addition, in this specification, the thickness of a nonwoven fabric is the thickness of an absorption auxiliary sheet, an absorption layer, and the whole absorber measured by observing the cross section of an absorber and applying a scale. The total thickness of each layer in the cross section is equal to the total thickness of the absorber. The apparent density of the nonwoven fabric was determined by calculation from the thickness of each layer measured as described above and the basis weight (mass per unit area) of each layer.

{Manufacture of absorption support sheet 10}
The absorption assisting sheet 10 is formed by, for example, arranging a gas permeable carrier sheet on a mesh endless belt, and depositing the raw material fibers on the gas permeable carrier sheet while being mixed in the air in an air laid web forming apparatus. Forming an airlaid web by forming a web (web forming step), and heating the obtained airlaid web to bond the fibers contained in the airlaid web (fiber bonding step) It can be manufactured by a manufacturing method.

The air laid type web forming apparatus generally includes a nozzle that discharges an intake air flow for uniformly mixing raw fibers in air, and a suction box disposed below the mesh endless belt. The intake flow passes through the mesh endless belt and is sucked into the suction box. When the raw material fibers are supplied to the web forming apparatus, the raw material fibers are mixed by the intake air flow and fall onto the mesh endless belt, and are deposited on the air-permeable carrier sheet fed out on the mesh endless belt. It is formed.
The air permeable carrier sheet is not particularly limited as long as it can pass an intake air flow and can hold an air laid web.

As the raw material fibers, those mentioned above are used.
The performance of the formed absorption assisting sheet 10 can be adjusted by adjusting the type and blending amount of the fibers constituting the raw fiber.
For example, as a raw material fiber for forming an absorption assisting sheet, it is formed by blending a highly crimped synthetic fiber or a high melting point fiber (Y) or by increasing the fiber diameter of the heat-fusible fiber (X). Since the binding points between the raw material fibers in the absorption assisting sheet 10 are reduced and the gaps are increased, an absorption assisting sheet excellent in texture and touch can be obtained. Further, the same effect can be obtained by reducing the mass ratio of the resin (A) and the resin (B) in the heat-fusible fiber (x2) (for example, the core-sheath composite ratio in the core-sheath structure).
On the contrary, by adding high heat-fusible fiber (X) or by reducing the fiber diameter, the shape retention of the absorption assisting sheet is improved, and the high-viscosity liquid or semi-solid absorption object passes. An absorption assisting sheet having excellent properties can be obtained.

The formed air laid web can be heat-treated by a general thermal bond method, and examples thereof include a method of introducing the air laid web into a heating furnace, a method of treating the air laid web with hot air, and the like.
As the hot air treatment, a method in which the web is heat-treated by passing through a through air dryer provided with a rotating drum having air permeability on the peripheral surface (hot air circulation rotary drum method), or the web allows hot air to penetrate the web. The method (hot air circulation conveyor oven system) etc. which are heat-processed by passing through the box type dryer which can be mentioned.
In addition, the thermal bond method by a hot air process may be called an air through method or a through air method.
The heat processing temperature should just be more than melting | fusing point of resin (A) (resin (A) contained in heat-fusible fiber (X)) contained in an air-laid web. When heated to a temperature equal to or higher than the melting point of the resin (A), the resin (A) is melted and the fibers are bonded to each other through the melted resin (A). However, when the fiber (x2) or the high melting point fiber (Y) is included as the raw material fiber, the temperature is lower than the melting point of the resin (B) contained in the fiber.
When the airlaid web includes latently crimped synthetic fibers, the heat treatment in the fiber bonding step may also serve as a heat treatment for revealing the crimps of the latently crimped synthetic fibers.
In addition, before and after the fiber bonding step, a step of performing a heat treatment for revealing the crimp of the latent crimped synthetic fiber may be provided.

After the fiber bonding step, a hot press treatment may be performed for the purpose of finely adjusting the density of the formed nonwoven fabric. The press pressure in that case is, for example, a low pressure of 5 kg / cm ² or less, preferably 1 kg / cm ² or less, and is performed at a pressure smaller than that of a hot press process generally performed as a fiber bonding step for bonding fibers together.

The absorption assisting sheet 10 is obtained by peeling the air-permeable carrier sheet from the nonwoven fabric obtained as described above.
The air-permeable carrier sheet may be left as it is without being peeled off. When leaving as it is without peeling, it is preferable to use a biodegradable carrier sheet as the air-permeable carrier sheet. An example of such a sheet is tissue paper.

<Second Embodiment>
FIG. 2 is a schematic longitudinal sectional view illustrating the configuration of the absorption assisting sheet 20 according to the second embodiment of the present invention. Note that, in the embodiments described below, the same reference numerals are given to the components corresponding to the first embodiment described above, and the detailed description thereof is omitted.
In the absorption auxiliary sheet 20, the apparent density of the surface side half in contact with the object to be absorbed is 0.03 g / cm ³ or more in the thickness of the absorption auxiliary sheet, and the apparent density of the half on the opposite side is the apparent density of the half on the surface side. Except for being smaller than the density, the configuration is the same as the absorption assisting sheet 10.
The absorption assisting sheet 20 is used so that the object to be absorbed first comes into contact with a surface having an apparent density of 0.03 g / cm ³ or more.
In the present embodiment, the apparent density of the half on the surface side in contact with the object to be absorbed is 0.03 g / cm ³ or more, and the apparent density of the half on the opposite side is smaller than the apparent density of the half on the surface side. Liquid that quickly permeates the opposite side of the lower layer with a low apparent density, and reverses the absorption target to the surface side due to the surface side with an apparent density of 0.03 g / cm ³ or more. (Wet back) can be effectively prevented.
As the raw material fiber used for the absorption assisting sheet 20, the same raw material fiber as that used for the absorption assisting sheet 10 can be used. The apparent density of the non-woven fabric constituting the absorption assisting sheet 20 can be adjusted according to the blending and production conditions of the raw fiber, and is configured by shortening the fiber length of the raw fiber or using raw fiber having a small fiber diameter. The bulkiness of the nonwoven fabric can be reduced and the apparent density can be increased. On the contrary, the apparent density can be increased by using crimped raw fibers, especially latent crimpable raw fibers, or using hollow raw fibers. Can be reduced. The apparent density can also be adjusted by a hot press process used as a trace of the fiber bonding step when manufacturing the nonwoven fabric. As a method of reducing the apparent density on the opposite surface side from the surface side in contact with the object to be absorbed, it is possible to reduce the apparent density and the raw material fiber having a composition that can increase the apparent density when forming the airlaid web. And a method of forming a web in which different raw material fibers are sequentially laminated, and a non-woven fabric having an apparent density of 0.03 g / cm ³ or more is laminated on the surface of a non-woven fabric layer having a density lower than that. The method can be used. In the case of a method in which the raw material fibers to be supplied are switched at the time of forming the airlaid web, the raw material fibers can be switched step by step, but the bulk density is increased by supplying the raw material fibers having a continuously inclined composition. A continuously inclined configuration can also be used.

{Manufacture of absorption auxiliary sheet 20}
The absorption auxiliary sheet 20 is, for example, a gas-permeable carrier sheet disposed on a mesh-like endless belt, and raw fiber is deposited on the gas-permeable carrier sheet while being mixed in the air using an airlaid web forming apparatus. Forming an airlaid web by forming a web (web forming step), and heating the obtained airlaid web to bond the fibers contained in the airlaid web (fiber bonding step) It can be manufactured by a manufacturing method. The web forming process and the fiber bonding process can be performed in the same manner as the web forming process and the fiber bonding process described in the method for manufacturing the absorption assisting sheet 10, respectively.
After the fiber bonding step, a hot press treatment may be performed for the purpose of finely adjusting the density of the formed nonwoven fabric. The press pressure in that case is, for example, a low pressure of 5 kg / cm ² or less, preferably 1 kg / cm ² or less, and is performed at a pressure smaller than that of a hot press process generally performed as a fiber bonding step for bonding fibers together.
Further, in the web forming step, the raw fiber for low apparent density is deposited while being mixed in the air in the air laid type web forming apparatus to form a low apparent density web, and then for the high apparent density. The air-laid web having a region having a high apparent density on the surface side and a region having a low apparent density on the opposite surface side is obtained by depositing raw material fibers in the air while mixing them in the air to form a high apparent density web. I can do it. By heating the air laid web, the fibers contained in the air laid web are bonded to each other, and an absorption assisting sheet having different apparent densities on the surface side and the opposite surface side can be obtained.
In this example, raw fiber for low apparent density is supplied as raw fiber, and then raw fiber for high apparent density is supplied. However, on the contrary, first, raw fiber for high apparent density is supplied. Subsequently, raw fiber for low apparent density may be supplied. By reversing this, the absorption auxiliary sheet 20 having a higher apparent density on the surface side can be obtained.
However, it is preferable to supply the raw fiber for high apparent density first. Usually, the raw fiber for high apparent density that gives the liquid retention property of the absorption object has a higher basis weight, and the raw fiber that allows the absorption object to permeate has a lower apparent density. Therefore, it is more difficult to mix the raw fiber for high apparent density and the raw fiber for low apparent density when the raw fiber for high apparent density is supplied first, and the region for high apparent density and the region for low apparent density. Each function is easy to fully demonstrate.

The absorption assisting sheet 20 can also be obtained by laminating a thinner non-woven fabric to the above thickness. In that case, the nonwoven fabrics constituting the absorption assisting sheet do not necessarily have to be bonded to each other. Non-woven fabric with an apparent density of 0.03 g / cm ³ or more is used as the non-woven fabric on the surface side half in contact with the object to be absorbed, and non-woven fabric with an apparent density smaller than the apparent density of the half on the surface side is used as the non-woven fabric on the opposite side half. Can be performed by laminating a plurality of nonwoven fabrics whose apparent density has been adjusted in advance according to the conditions of the hot press treatment as described above. This is a preferable method because it can be designed according to the amount of the object to be absorbed. The absorption assisting sheet can be used by superimposing it on the surface of the absorber including at least the absorption layer. However, in this case as well, the absorber and the absorption assisting sheet 20 are not necessarily bonded to each other.
<Third embodiment>
FIG. 3 is a schematic longitudinal sectional view illustrating the configuration of the absorption assisting sheet 30 according to the third embodiment of the present invention. Note that, in the embodiments described below, the same reference numerals are given to the components corresponding to the first or second embodiment described above, and detailed description thereof will be omitted.
The absorption assisting sheet 30 has the same configuration as that of the absorption assisting sheet 20 except that the apparent density of the front half on contact with the object to be absorbed is smaller than the apparent density of the rear half.
The absorption assisting sheet 30 is used such that the object to be absorbed first comes into contact with the surface with the smaller apparent density.
In the present embodiment, since the apparent density of the half on the surface side in contact with the object to be absorbed is smaller than the apparent density of the half on the opposite side, the object to be absorbed does not remain on the outermost surface of the absorption assisting sheet 30, and the absorption assist It is possible to prevent the transfer to the one in contact with the sheet again. As the raw material fiber used for the absorption assisting sheet 30, the same raw material fiber as that used for the absorption assisting sheet 10 can be used.

{Manufacture of absorption support sheet 30}
The absorption assisting sheet 30 is, for example, a gas-permeable carrier sheet disposed on a mesh-like endless belt, and raw fiber is deposited on the gas-permeable carrier sheet while being mixed in the air by an airlaid web forming apparatus. Forming an airlaid web by forming a web (web forming step), and heating the obtained airlaid web to bond the fibers contained in the airlaid web (fiber bonding step) It can be manufactured by a manufacturing method. The web forming process and the fiber bonding process can be performed in the same manner as the web forming process and the fiber bonding process described in the method for manufacturing the absorption assisting sheet 10, respectively.
After the fiber bonding step, a hot press treatment may be performed for the purpose of finely adjusting the density of the formed nonwoven fabric. The press pressure in that case is, for example, a low pressure of 5 kg / cm ² or less, preferably 1 kg / cm ² or less, and is performed at a pressure smaller than that of a hot press process generally performed as a fiber bonding step for bonding fibers together.
Further, in the web forming process, a high apparent density web is formed by mixing raw fiber for high apparent density while mixing in air in an air laid type web forming apparatus, and subsequently, for low apparent density. An airlaid web having a low apparent density region on the surface side and a high apparent density region on the opposite side by depositing raw material fibers in the air while mixing them to form a low apparent density web I can get it. By heating the air laid web, the fibers contained in the air laid web are bonded to each other, and an absorption assisting sheet having different apparent densities on the surface side and the opposite surface side can be obtained.
In this example, the raw fiber for the high apparent density is supplied as the raw fiber, and then the raw fiber for the low apparent density is supplied. However, the raw fiber for the high apparent density is supplied first. Subsequently, raw fiber for low apparent density may be supplied. By reversing this, the absorption auxiliary sheet 30 having a lower apparent density on the surface side can be obtained.
It is preferable to supply raw fibers for high apparent density first. Usually, the raw fiber for high apparent density that gives the liquid retention property of the absorption object has a higher basis weight, and the raw fiber that allows the absorption object to permeate has a lower apparent density. Therefore, it is more difficult to mix the raw fiber for high apparent density and the raw fiber for low apparent density when the raw fiber for high apparent density is supplied first, and the region for high apparent density and the region for low apparent density. Each function is easy to fully demonstrate.

The absorption assisting sheet 30 can also be obtained by laminating a thinner non-woven fabric to the above thickness. In that case, the nonwoven fabrics constituting the absorption assisting sheet do not necessarily have to be bonded to each other. Formed by laminating a non-woven fabric with a small apparent density as a non-woven fabric on the surface side half in contact with the object to be absorbed, and a non-woven fabric with an apparent density larger than the apparent density of the half on the surface side as a non-woven fabric on the opposite side. Can be performed by laminating a plurality of nonwoven fabrics whose apparent density has been adjusted in advance according to the conditions of the heat press treatment as described above, and by adjusting the number of layers, the target high-viscosity absorbent object can be obtained. This is a preferable method because it can be designed according to the quantity. The absorption assisting sheet can be used by being superimposed on the surface of the absorber including at least the absorption layer, but in this case, the absorber and the absorption assisting sheet 30 do not necessarily have to be bonded to each other.
<Fourth embodiment>
FIG. 4 is a schematic longitudinal sectional view illustrating the configuration of the absorber 40 according to the fourth embodiment of the present invention. Note that, in the embodiments described below, the same reference numerals are given to the components corresponding to the first to third embodiments described above, and the detailed description thereof is omitted.
In the absorber 40, the apparent density of the half on the surface side in contact with the object to be absorbed is 0.03 g / cm ³ or more, and the apparent density of the half on the opposite side is the apparent density of the half on the surface side. It is an absorbent body in which a smaller absorbent auxiliary sheet 20 is laminated on an absorbent layer 21 made of a non-woven fabric obtained by heat-treating an airlaid web composed of raw material fibers having a cellulose fiber content of 5% by mass to 98% by mass. The absorbent body of the present invention in which the absorption assisting sheet of the present invention is laminated on an absorbent layer made of a non-woven fabric obtained by heat-treating an air-laid web composed of raw material fibers having a cellulose fiber content of 5 mass% to 98 mass%. In the absorbent body according to the present invention, the absorbent auxiliary sheet 10, 20, or 30 may be laminated on the absorbent layer 21.
In the present embodiment, the absorption assisting sheet 20 is stacked on the liquid absorbent sheet 21 having water absorbency or liquid absorbency to a low viscosity liquid, and a high viscosity absorption object difficult to be absorbed by the absorption layer 21 is held. Then, the absorbent layer 21 is used by being laminated on the surface of the absorption layer 21 so that the object to be absorbed first comes into contact with the surface of the absorption assisting sheet 20 so that the absorption layer 21 can be assisted. In addition, as described above, the absorption assisting sheet 20 quickly transmits the object to be absorbed to the opposite surface side having a small apparent density in the lower layer, and is excellent in the retention with an apparent density of 0.03 g / cm ³ or more. By the surface side, it is possible to effectively prevent liquid return (wet back) in which the absorption object flows back to the surface side.

{Absorbent layer 21}
The raw fiber of the absorbent layer 21 has a cellulose fiber content of 5% by mass or more and 98% by mass or less. In addition, this content is a ratio with respect to the total amount (100 mass%) of the raw material fiber of the absorption layer 21. FIG.

The web of the absorbent layer 21 is bulky because it is formed by the airlaid method as described above. Moreover, by including a cellulose fiber, the space | gap between the raw material fibers in the absorption layer 21 becomes small, and a liquid absorptivity improves. Since the cellulose fiber is a hydrophilic fiber, the water absorption is particularly high.
Moreover, by including cellulose fibers, the binding points between the raw material fibers in the absorbent layer 21 do not become excessive, and the absorbent layer 21 decomposes (hydrolyzes) when it comes into contact with a large amount of water. In addition, biodegradability is improved because it is easy to decompose when processing such as burying in soil.

It is preferable that the raw material fiber of the absorption layer 21 further contains a heat-fusible fiber (X).
In this case, the content of the cellulose fiber in the raw fiber of the absorbent layer 21 is 5% by mass or more and 95% by mass or less, and the content of the heat-fusible fiber (X) is 5% by mass or more and 15% by mass or less. It is preferable that the content of the cellulose fiber is 50% by mass or more and 95% by mass or less, and the content of the heat-fusible fiber (X) is more preferably 5% by mass or more and 10% by mass or less.
As described above, the resin (A) in the heat-fusible fiber (X) is a resin having a relatively low melting point, and functions as a heat-fusible component in the fiber bonding step by the thermal bond method. Therefore, when 5 mass% or more of the heat-fusible fiber (X) is contained in the raw material fiber of the absorption layer 21, there are sufficient binding points between the raw material fibers in the formed absorption layer 21, and the shape retention is maintained. Improves. By improving the shape retention, even when the liquid absorption amount in the absorption layer 21 becomes saturated, the thickness decrease due to the liquid weight is small, and the thickness decreases when external force is applied to the absorption layer 21. Hateful. Therefore, it is possible to suppress a decrease in the amount of liquid that can be absorbed due to the decrease in thickness. It is thought that liquid retention improves by these acting synergistically.
Even when the heat-fusible fiber (X) is contained, if the content is 15% by mass or less, excellent biodegradability can be maintained.

[Cellulose fiber]
As a cellulose fiber, the various cellulose fibers conventionally used for the absorber can be used. Examples of the cellulose fiber material include pulp, rayon, cotton, and cupra.
Cellulose fibers are preferably pulp fibers in terms of fiber length, foreign matter, productivity, raw material price, and the like.
Examples of the pulp fiber include wood pulp (conifers, hardwoods), rug pulp, linter pulp, linen pulp, non-wood pulp such as straw, three bases, and husk pulp, and raw pulp such as waste paper pulp. As the raw material pulp, any of mechanical pulp (GP, RGP, TMP, etc.) and chemical pulp (sulfite pulp, kraft pulp, etc.) can be used. Among these, kraft pulp is preferable from the viewpoints of supply amount, quality stability, cost, and the like.
The fiber length of the pulp fiber is preferably 4 mm or less, and more preferably 3 mm or less.
As the pulp fiber, normal wood pulp or the like can be used. However, in order to obtain a low-density non-woven fabric and ease of blending with the thermoplastic synthetic resin fiber, etc., the courseness required by the length average weight is required. 0.1 mg / m to 0.3 mg / m, preferably 0.12 mg / m to 0.2
Those of 5 mg / m are preferably used.

As a cellulose fiber, 1 type may be used independently or 2 or more types may be used together.
The ratio of the cellulose fiber in the raw material fiber of the absorption layer 21 is 5 mass% or more and 98 mass% or less, and 50 mass% or more and 95 mass% or less are preferable. When the ratio of the cellulose fiber is 5% by mass or more, the biodegradability and water decomposability are sufficiently improved. Liquid retention improves by being 98 mass% or less.

[Heat-bondable fiber (X)]
Examples of the fiber (x1) and the fiber (x2) in the heat-fusible fiber (X) are the same as those described above.
The heat-fusible fiber (X) contained in the raw fiber of the absorbent layer 21 and the heat-fusible fiber (X) contained in the raw material fiber of the absorption assisting sheet 20 may be the same or different.
In the raw material fiber of the absorbent layer 21, the fiber length of the heat-fusible fiber (X) (fiber (x1), fiber (x2)) is preferably 2 to 20 mm, more preferably 2 to 10 mm, and further preferably 2 to 6 mm. . With such a fiber length, when forming an air laid web, these fibers are randomly stacked three-dimensionally, and as a result, the absorbent layer 21 is bulky and exhibits excellent liquid retention It is easy to become. Moreover, it becomes difficult to lose shape. On the other hand, if the fiber length is less than the lower limit of this range, the fibers in the absorbent layer 21 become dense, and the absorbability may decrease.
The fiber diameter of the heat-fusible fiber (X) is preferably 0.5 to 74 dtex, more preferably 0.8 to 35 dtex, and still more preferably 1.0 to 20 dtex. When the fiber diameter is such, the absorbent layer 21 is bulky and easily exhibits excellent liquid retention. Moreover, it becomes difficult to lose shape. On the other hand, if the fiber diameter is less than the lower limit of this range, the absorbability tends to be inferior due to an increase in resistance when absorbing the liquid. If the fiber diameter exceeds the upper limit of this range, the fiber itself becomes stiff and the tingling sensation increases and the touch tends to deteriorate.

As the heat-fusible fiber (X), one type may be used alone, or two or more types may be used in combination.
The proportion of the heat-fusible fiber (X) in the raw material fibers of the absorbent layer 21 is preferably 5% by mass or more and 15% by mass or less, and more preferably 5% by mass or more and 10% by mass or less.
The total ratio of the heat-fusible fiber (X) and the cellulose fiber in the raw material fibers of the absorbent layer 21 is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. . When the total ratio is 50% by mass or more, liquid retention, water disintegration, and biodegradability are improved. The upper limit of the ratio is not particularly limited, and may be 100% by mass. It can be appropriately set in consideration of other fibers that are arbitrarily blended.

[Any raw fiber]
The raw material fibers of the absorbent layer 21 may contain fibers other than the heat-fusible fibers (X) and cellulose fibers.
As this other fiber, what is necessary is just the thing which does not impair the biodegradability of the absorption layer 21, for example, the said high melting point fiber (Y), PVA fiber, etc. are mentioned. Examples of the high melting point fiber (Y) and the PVA fiber are the same as those described above.
When the high melting point fiber (Y) is contained, the content of the high melting point fiber (Y) in the raw material fiber of the absorbent layer 21 is preferably 3% by mass or more and 48% by mass or less.

As a raw material fiber of the absorption layer 21, what contains a cellulose fiber 5 mass% or more and 98 mass% or less should just be contained, Furthermore, the thing containing heat-fusible fiber (X) is preferable.
Among these, cellulose fiber 5% by mass or more and 95% by mass or less and heat-fusible fiber (X) 5% by mass or more and 15% by mass or less are contained in terms of excellent shape retention and water retention of the sheet after water absorption. And 5% by mass to 95% by mass of the cellulose fiber, 5% by mass to 15% by mass of the heat-fusible fiber (X), and 0% by mass to 48% by mass of the high melting point fiber (Y). More preferably, it consists of

The absorbent layer 21 may be composed of only the first raw material fiber, and if necessary, other components other than the raw material fiber of the absorbent layer 21 may be added as long as the effects of the present invention are not impaired. You may contain.
As the other components, known additives can be used without particular limitation as additives in the absorbent sheet, and examples thereof include functional powders, functional fibers, and functional liquids.
As the functional powder, those having any one or more of a deodorizing function, an antibacterial function, an antiviral function, an antiallergen function, an antifungal function, an aroma function, a functional liquid and the like are preferable. Activated carbon, chitin, chitosan, scallop shell, titanium oxide, titanium dioxide, magnesium oxide, plant extract, mushroom extract, catechin, flavonol, cyclodextrin, collagen fiber, iron oxide, citric acid, zinc pyrithione, hinokitiol, eucalyptus extract, etc. Can be mentioned.

Absorbing layer 21 preferably has a basis weight of 30~1000g / ^{m 2,} more preferably from 40~700g / ^{m 2,} further preferably 50 to 500 g / ^{m 2.} When the basis weight of the absorbent layer 21 is equal to or higher than the lower limit of the above range, the ability to hold the liquid is excellent. When the basis weight of the absorbent layer 21 is not more than the upper limit of the above range, the wearing feeling and handleability of the absorbent body 40 and the productivity of the absorbent layer 21 are good.

Absorbing layer 21 preferably has a density of 0.01 to 0.1 g / cm ^3, more preferably ^{0.01~0.08g / cm 3, 0.02~0.06g / cm} 3 More preferably. When the density exceeds the upper limit of the above range, there are few voids or the size of the voids is too small, and the absorption rate may be slow. When the density is less than the lower limit of the above range, the number of voids in the absorption layer 21 becomes too large or the size of the voids becomes too large, and the liquid absorption amount in the absorption layer 21 becomes saturated. Further, the thickness reduction due to the weight of the liquid becomes large, and the thickness is likely to decrease when an external force is applied to the absorption layer 21, so that the amount of liquid that can be absorbed may be reduced. Even if the liquid is once absorbed, it is difficult to hold it, and there is a risk of reversal.

{Manufacture of absorber 40}
For example, the absorbent layer 21 is formed by arranging a gas-permeable carrier sheet on a mesh-like endless belt, and depositing the raw material fibers on the gas-permeable carrier sheet while mixing the raw fibers in the air using an airlaid web forming apparatus. A process comprising a step of obtaining an air laid web by forming a web (web forming step), and a step of bonding the fibers contained in the air laid web by heating the air laid web (fiber bonding step). It can be manufactured by a method.
Alternatively, in the web forming step, the raw fiber of the absorbent layer 21 is deposited in the air while being mixed in the air-laid web forming apparatus to form the web of the absorbent layer 21. The absorbent body 40 in which the absorbent auxiliary sheet 20 is laminated on the absorbent layer 21 is obtained by performing a step of obtaining an airlaid web by depositing raw material fibers while being mixed in the air to form a web of the absorbent auxiliary sheet 20. It can also be manufactured at once.

The web forming step and the fiber bonding step can be performed in the same manner as the web forming step and the fiber bonding step described in the method for manufacturing the absorbent sheet 10, respectively. After the fiber bonding step, a hot press treatment may be performed for the purpose of finely adjusting the density of the formed nonwoven fabric. The press pressure in that case is, for example, a low pressure of 5 kg / cm ² or less, preferably 1 kg / cm ² or less, and is performed at a pressure smaller than that of a hot press process generally performed as a fiber bonding step for bonding fibers together.
Further, in the web forming step, the raw fiber for low apparent density is deposited while being mixed in the air in the air laid type web forming apparatus to form a low apparent density web, and then for the high apparent density. The air-laid web having a region having a high apparent density on the surface side and a region having a low apparent density on the opposite surface side is obtained by depositing raw material fibers in the air while mixing them in the air to form a high apparent density web. I can do it. By heating the air laid web, the fibers contained in the air laid web are bonded to each other, and an absorption assisting sheet having different apparent densities on the surface side and the opposite surface side can be obtained.
In this example, raw fiber for low apparent density is supplied as raw fiber, and then raw fiber for high apparent density is supplied. However, on the contrary, first, raw fiber for high apparent density is supplied. Subsequently, raw fiber for low apparent density may be supplied. By reversing this, the absorption auxiliary sheet 20 having a lower apparent density on the surface side can be obtained.
However, it is preferable to supply the raw fiber for high apparent density first. Usually, the raw fiber for high apparent density that gives the liquid retention property of the absorption object has a higher basis weight, and the raw fiber that allows the absorption object to permeate has a lower apparent density. Therefore, it is more difficult to mix the raw fiber for high apparent density and the raw fiber for low apparent density when the raw fiber for high apparent density is supplied first, and the region for high apparent density and the region for low apparent density. Each function is easy to fully demonstrate.

The absorption assisting sheet 20 can also be obtained by laminating a thinner non-woven fabric to the above thickness. In that case, the nonwoven fabrics constituting the absorption assisting sheet do not necessarily have to be bonded to each other. Non-woven fabric with an apparent density of 0.03 g / cm ³ or more is used as the non-woven fabric on the surface side half in contact with the object to be absorbed, and non-woven fabric with an apparent density smaller than the apparent density of the half on the surface side is used as the non-woven fabric on the opposite side half. Can be performed by laminating a plurality of nonwoven fabrics whose apparent density has been adjusted in advance according to the conditions of the hot press treatment as described above. This is a preferable method because it can be designed according to the amount of the object to be absorbed. Although the absorption auxiliary sheet 20 is laminated on the surface of the absorption layer 21, the absorption layer 21 and the absorption auxiliary sheet 20 are not necessarily bonded to each other.

As a method for forming the absorption assisting sheet 20 by laminating an absorption assisting sheet on the absorbing layer 21 or by laminating a plurality of non-woven fabrics, an adhesive substance (for example, a resin (A) powder that exhibits an adhesive action by heat fusion is used. A body, etc.), thereby bonding the absorbent layer 21 and the absorption auxiliary sheet 20 or bonding a plurality of nonwoven fabrics forming the absorption auxiliary sheet 20 (the amount of adhesive used is, for example, 3 to 15 g / m ²⁾ . ) In this case, you may adhere | attach only the peripheral part of the some nonwoven fabric which forms the absorption layer 21, the absorption auxiliary sheet 20, or the absorption auxiliary sheet 20. FIG. Alternatively, without using an adhesive substance, the entire surface or only the peripheral portion thereof may be joined by thermal fusion using the thermal fusion property of the thermal fusion fiber (X) contained in the absorbent layer 21. Further, a non-woven fabric having permeability is formed into a bag shape, and the absorbent layer 21 is inserted therein, and the peripheral portion of the bag-shaped non-woven fabric into which the absorbent layer 21 is inserted is bonded. You may integrate without.

Further, as described above, the absorption auxiliary sheet 20 is manufactured by using an adhesive material, utilizing heat-fusibility, or adopting a method of integrating without bonding, as described above. In addition to the method of laminating the absorption assisting sheet 20 on 21, for example, a method of providing the absorption assisting sheet 20 on at least one surface of the absorbent layer 21 while producing the absorbing layer 21 can also be mentioned.
Further, the web constituting the absorption assisting sheet 20 may be obtained by sequentially depositing a plurality of types of raw material fibers having different fiber types and compositions, fiber lengths, or fiber diameters. Similarly, the web constituting the absorbent layer 21 may be obtained by sequentially depositing a plurality of types of raw material fibers for the absorbent layer having different fiber types and compositions, fiber lengths, or fiber diameters.
For example, when the ratio of the heat-fusible fiber (X) in the raw fiber is lowered, the shape retention and permeability are lowered, but the texture and the touch tend to be improved. Therefore, the ratio of the heat-fusible fiber (X) in the raw fiber constituting the outer side of the auxiliary absorption sheet 20 (the side that becomes the surface of the absorber 40) is lowered (for example, 5 to 10% by mass), and the auxiliary absorption sheet When the ratio of the heat-fusible fiber (X) in the raw material fibers constituting the inner side (absorbing layer 21 side) of 20 is increased (for example, 20 to 50% by mass), the texture and feel of the outer surface is good and the retention is maintained. The absorption assisting sheet 20 having good shape and permeability can be obtained.

The absorption assisting sheet of the present invention is disposed on the surface of the absorber, and has a permeability capable of quickly permeating and absorbing under the surface even if it is an object to be absorbed with high viscosity. A highly viscous object to be absorbed, which has been difficult to absorb, is held in the voids in the interior to assist the function of the absorber. The absorbent body of the present invention having this absorption assisting sheet has a liquid retaining property that can sufficiently hold the liquid contained in the absorbed object to be absorbed.
Further, the absorption assisting sheet and the absorbent body of the present invention have water decomposability and have an advantage of being easily discarded. For example, it can be disposed of in a flush toilet after use. Moreover, since it has biodegradability, it can be buried in soil and discarded.
Therefore, the absorption assisting sheet and the absorber of the present invention are various absorption objects such as water, organic solvents, inks, oils, solutions and gels in which other components are dissolved, and those in which they are mixed with a solid content. And is useful as various existing absorbent articles or as an absorbent auxiliary sheet (sheet constituting a surface in contact with an object to be absorbed) of the absorbent article.
The absorption assisting sheet of the present invention is used so as to come into contact with the object to be absorbed before the surface of the absorption layer.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited to these Examples.
The raw material fibers used in the following examples are as follows.
[Heat-bonding fiber]
PBS / PLA 3.3 dt: Synthetic fiber having a concentric core-sheath structure having polybutylene succinate (PBS) as a sheath and polylactic acid (PLA) as a core (fiber diameter 3.3 dtex, fiber length 5 mm, core-sheath composite ratio = 6/4). Daiwabo Polytech NBF (KK) PL (6/4) 3.3dt
PBS / PLA 17 dt: Synthetic fiber having an eccentric core-sheath structure in which PBS is a sheath and PLA is a core (fiber diameter 17 dtex, fiber length 5 mm, core-sheath composite ratio = 6/4). Daiwabo Polytech NBF (KK) PLV (6/4) 17 dt.

[Latent crimped fiber with hollow]
PLA / PLA17dt: Synthetic fiber having a structure in which PLA / PLA is arranged in a side-by-side manner and has a hollow portion (fineness: 17 dtex, fiber length: 5 mm). Nippon Ester Co., Ltd. HP8F 17. T5mm
[PVA fiber]
PVA 2.2 dt: PVA fiber (fiber diameter 2.2 dtex, fiber length 6 mm). Kuraray WN2 × 6.
[Cellulose fiber]
Pulp: Conifer craft bleached pulp.

<Test Example 1>
Absorbers (Samples 1-1 to 11) in which an absorption assisting sheet having the same configuration as that of the absorption assisting sheet 10 shown in FIG. 1 was laminated on the absorption layer were manufactured by the following procedure.
Mass shown in the Absorbing Layer column of Table 1 with pulp and heat-fusible fiber PBS / PLA 3.3 dt in an airlaid web forming machine while feeding tissue paper onto a mesh endless belt mounted on a conveyor and running By supplying the basis weight of the absorbent layer to the value shown in Table 1, and dropping and accumulating on the mesh endless belt while being uniformly mixed in air, An absorbent layer web was formed. Subsequently, the heat-fusible fiber PBS / PLA17dt, the latent crimpable fiber PLA / PLA17dt and PVA fiber having a hollow were supplied so that the basis weight of the absorption assisting sheet was the value shown in Table 1, and in the air An air support web was obtained by forming the absorbent auxiliary sheet web on the absorbent layer web by lowering it along with the intake air flow and dropping it onto the mesh endless belt while mixing uniformly.
Next, this air laid web was passed through a box type dryer (hot air circulating conveyor oven) that allows hot air to pass through the web, and treated with hot air to obtain a nonwoven fabric (absorbent body). The hot air treatment temperature (hot air circulation conveyor oven temperature) was 145 ° C. Then, the tissue paper was peeled off from the absorption layer, and the absorbent bodies of Samples 1-1 to 10 including the absorption auxiliary sheet layer and the absorption layer shown in Table 1 were obtained.

<Test Example 2>
Absorption assisting sheets (samples 2-1 to 6) having the same configuration as the absorption assisting sheets 20 and 30 shown in FIGS. 2 and 3 were produced by the following procedure.
While feeding tissue paper onto a mesh-like endless belt that is mounted on a conveyor, the air-laid web forming machine has a heat-bondable fiber PBS / PLA17dt, a latent crimpable fiber PLA / PLA17dt and PVA with a hollow. The fibers are supplied at a mass ratio shown in Table 2 so that the basis weight of the absorption assisting sheet becomes the value shown in Table 2, and while being uniformly mixed in the air, the fibers are lowered along with the intake air flow on the mesh endless belt. By dropping and depositing, an absorbent auxiliary sheet web was formed to obtain an airlaid web.
Next, this air laid web was passed through a box type dryer (hot air circulating conveyor oven) that allows hot air to pass through the web, and was subjected to hot air treatment to obtain a nonwoven fabric for an absorbent auxiliary sheet. The hot air treatment temperature (hot air circulation conveyor oven temperature) was 145 ° C. Then, tissue paper was peeled off from the nonwoven fabric for absorption auxiliary sheets, and the nonwoven fabric for absorption auxiliary sheets was obtained. As shown in Table 2, this non-woven fabric for absorption auxiliary sheet was laminated as a single layer or a combination, and the absorption auxiliary sheets of Samples 2-1 to 11 shown in Table 2 were obtained.

<Test Example 3>
Absorbers (samples 3-1 to 4) having the same configuration as that of the auxiliary absorption sheet 40 shown in FIG. 4 were produced by the following procedure.
While feeding tissue paper onto a mesh endless belt that is mounted on a conveyor, pulp and heat-fusible fiber PBS / PLA 3.3 dt are added to a web forming machine of airlaid method at a mass ratio shown in Table 3. The air-laid web for the absorbent layer on the tissue paper is supplied so that the amount becomes the value shown in Table 3 and is dropped and deposited along with the intake air flow onto the mesh endless belt while being uniformly mixed in the air. Got.
Next, this air laid web was passed through a box type dryer (hot air circulating conveyor oven) that allows hot air to pass through the web, and treated with hot air to obtain a nonwoven fabric (absorbent body). The hot air treatment temperature (hot air circulation conveyor oven temperature) was 145 ° C. Thereafter, the tissue paper was peeled off from the absorbent layer to obtain an absorbent layer nonwoven fabric.
In addition, while feeding tissue paper onto a mesh endless belt that is mounted on a conveyor, the air-laid web forming machine has a heat-fusible fiber PBS / PLA 17 dt and a latent crimpable fiber PLA / PLA 17 dt having a hollow. And PVA fibers are supplied at a mass ratio shown in Table 3 so that the basis weight is the value shown in Table 3. While being uniformly mixed in the air, it is lowered along with the intake air flow onto the mesh endless belt and dropped and deposited. By doing so, an airlaid web for an absorption assisting sheet was obtained on a tissue paper.
Next, this air laid web was passed through a box type dryer (hot air circulating conveyor oven) that allows hot air to pass through the web, and treated with hot air to obtain a nonwoven fabric (absorbent body). The hot air treatment temperature (hot air circulation conveyor oven temperature) was 145 ° C. Thereafter, the tissue paper was peeled off from the absorbent layer to obtain an absorbent auxiliary sheet nonwoven fabric.
The absorbent layer nonwoven fabric and the absorbent auxiliary sheet nonwoven fabric were combined and laminated as shown in Table 3 to obtain absorbent bodies of Samples 3-1 to 5-5.

Tables 1 to 3 show the total basis weight (g / m2) of the obtained absorber and absorption assisting sheet.
Further, the total thickness (mm) of the absorbent sheet, and the thickness (mm) of each of the absorption auxiliary sheet layer and the absorbent layer were measured by the following procedure. The density (g / cm ³ ) of each layer was calculated from the thickness and basis weight of each of the absorption assisting sheet layer and the absorption layer. The results are shown in Tables 1-3.
Moreover, in order to evaluate absorptivity about the absorber and absorption auxiliary sheet | seat of each example, the horizontal water absorption (g / m < ² >) and the liquid return prevention property were measured in the following procedures. Moreover, in order to evaluate the absorptivity of a high viscosity liquid about the absorber and absorption auxiliary sheet | seat of each example, the high viscosity liquid absorption time and the high viscosity liquid absorptivity were evaluated in the following procedures. Moreover, the water disintegration property of each absorber and the absorption auxiliary sheet was evaluated by the following procedure. The results are shown in Tables 1-3.

<Measurement of thickness of each layer of absorption layer and absorption auxiliary sheet>
The cross section of the absorber sample or the absorption auxiliary sheet sample was observed, and the thickness of the absorption auxiliary sheet layer, the absorption layer, and the entire absorber was measured by applying a scale. The total thickness of each layer in the cross section is equal to the thickness of the entire absorber.

<Measurement of horizontal water absorption>
A 10 × 10 cm sample was immersed in 0.9% physiological saline for 10 minutes, and the water absorption was measured after netting for 1 minute.
[Horizontal water absorption (g / m ² )] = (Water absorption, sample mass after netting (g) −sample mass before water absorption (g)) × 100

<Evaluation of high viscosity liquid absorption time>
(1) Put 15 ml of high-viscosity liquid on a 10 × 10 cm sample in a container of width 2 × length 5.5 × height 2 cm, and uniformly transfer the high-viscosity liquid to the sample surface.
(2) Remove the container, place a vinyl chloride plate on it, place a weight on it and apply a load of 30 kg / m ² for 1 minute.
(3) The PVC plate and the weight were removed, and the time from the absorption assisting sheet or the absorber surface until the gloss due to residual viscous liquid disappeared and absorbed was defined as the high viscosity liquid absorption time (minutes).
High viscosity liquid: Aqueous solution adjusted to a viscosity of 500 mPa · s with bentonite, glycerin, water and a polymer thickener <Evaluation of high viscosity liquid absorbency>
(1) Fix a 10 × 10 cm sample on a horizontal surface.
(2) Put 2 ml of high-viscosity liquid into a syringe and drop it onto the center surface of the sample. As the high viscosity liquid, an aqueous solution adjusted to a viscosity of 500 mPa · s with bentonite, glycerin, water and a polymer thickener was used.
(3) Roll a 100 mm diameter roller whose surface is treated with water repellency, slowly (one rotation / second) on the dropped liquid. The roller load (linear pressure) is 7 g / cm.
(3) Measure the width (a) and length (b) of the high-viscosity liquid spreading on the sample surface, and calculate the area of the diffused liquid (in the case of an ellipse, area = π × a × b / 4) .
(4) When the viscosity of the high-viscosity liquid is less than 8 cm ² ◎, when the viscosity is less than 12 cm ² ◯, when the high-viscosity liquid diffusion is less than 16 cm ² △, and when the high-viscosity liquid diffusion is 16 cm ² or more The high-viscosity liquid absorptivity was evaluated as x.
<Evaluation of liquid return prevention property of absorber>
(1) Fix a 10 × 10 cm absorber sample on a horizontal surface.
(2) Add 20 ml of physiological saline to a syringe and drop it onto the center surface of the sample.
(3) Cover the sample with a filter paper (Qualitative No. 2) and roll a water-repellent treated 100 mm diameter roller over the sample slowly (1 rotation / second) on the dropped solution. The roller load (linear pressure) is 5 g / cm.
(4) Observe the filter paper, ◎ if it is not wet by liquid return, there are parts that are wet by liquid return, but ○, 50% if less than 25% of the absorbent area that absorbed physiological saline The anti-recovery property was evaluated with Δ for less than, and x for filter paper that was 50% or more of the absorber area wetted by liquid return.
In addition, the liquid return prevention evaluation of only the absorption assisting sheet was cut to the same size as the absorption assisting sheet sample with the nonwoven fabric for absorbing layer shown in Test Example 3 having a basis weight of 103 g / m ² and a thickness of 4 mm. The absorption assisting sheet sample was laminated thereon, and the evaluation was performed in the same manner as the absorber sample.
<Evaluation of water disintegration>
A 3 × 3 cm sample and a 300 ml beaker containing 300 ml of water are placed on a magnetic stirrer and stirred for 3 minutes at a rotation speed of 800 rpm using a disc-shaped rotor having a diameter of 35 mm and a thickness of 12 mm. The state was confirmed (refer to JIS P 4501 Toilet paper ease test method).
Samples that collapsed and almost hydrolyzed ◎, those that almost collapsed and did not retain the original shape ○, those that have collapsed, but those that remain slightly △, some collapsed Although the prototype remains, it was evaluated as x.

上記結果に示すとおり、本発明実施例の吸収補助シートおよびそれを有する吸収体は、優れた水解性を有し、且つ高粘度液体吸収時間も短い優れた吸収シートであった。
一方、比較例の吸収層のみの吸収体では高粘度液体を吸収することが出来ず、比較例の吸収補助を有する吸収体も高粘度液体吸収時間が長く、高粘度液体に対する吸収性が劣っていた。

As shown in the above results, the absorption assisting sheets of the examples of the present invention and the absorbent bodies having the same were excellent absorbent sheets having excellent water decomposability and a short high-viscosity liquid absorption time.
On the other hand, a high viscosity liquid cannot be absorbed by the absorbent body only of the absorption layer of the comparative example, and the absorbent body having the absorption aid of the comparative example also has a long high viscosity liquid absorption time and is poor in absorbability for the high viscosity liquid. It was.

  10, 20, 30 ... Absorption assisting sheet, 21 ... Absorbing layer, 40 ... Absorber

Claims (9)

Absorption assisting sheet that assists the absorbent sheet by holding a high-viscosity liquid that is difficult to absorb with the absorbent sheet, overlaid on the absorbent sheet that absorbs water or has low viscosity. Because
An airlaid web comprising raw fibers containing a content of at least one heat-fusible fiber (X) selected from the following fibers (x1) and the following fibers (x2) from 2% by mass to 50% by mass absorbent auxiliary sheet basis weight was heat treated consists 50 g / ^{m 2} or more at least one layer of nonwoven fabric, and the apparent density is equal to or less than 0.015 g / cm ³ or more 0.045 g / cm ^3.

Fiber (x1): polybutylene succinate, poly (hydroxybutyrate / hydroxyhexanoate), polycaprolactone, poly (caprolactone / butylene succinate), poly (butylene succinate / adipate), poly (butylene succinate / carbonate) ), Poly (butylene adipate / terephthalate) and polyethylene succinate, a heat-fusible fiber comprising at least one resin (A).
Fiber (x2): a heat-fusible fiber comprising at least one resin (B) selected from polylactic acid, polyhydroxybutyrate, polyglycolic acid and cellulose acetate, and the resin (A).   2. The apparent density of the surface side half in contact with the object to be absorbed is 0.03 g / cm 3 or more in the thickness of the absorption assisting sheet, and the apparent density of the opposite side half is smaller than the apparent density of the surface side half. An absorption assisting sheet as described in 1.   The absorption assisting sheet according to claim 1, wherein the apparent density of the front half in contact with the object to be absorbed is smaller than the apparent density of the rear half of the thickness of the auxiliary absorbing sheet.   The absorption auxiliary sheet according to any one of claims 1 to 3, wherein the raw fiber further contains a high melting point fiber (Y) made of the resin (B).   The absorption auxiliary sheet according to any one of claims 1 to 4, wherein the raw fiber further comprises a latent crimpable conjugate fiber (Z) made of the following resin (B) and having a hollow portion.   The absorption auxiliary sheet according to any one of claims 1 to 5, wherein the raw fiber further contains a polyvinyl alcohol resin fiber.   The content of the heat-fusible fiber (X) in the raw fiber is 2% by mass or more and 50% by mass or less, and the content of the polyvinyl alcohol resin fiber is the content of the heat-fusible fiber (X). It is 50 mass% or more with respect to quantity, The absorption auxiliary sheet as described in any one of Claims 1 thru | or 6.   The absorption assisting sheet according to any one of claims 1 to 7, wherein the absorption assisting sheet has a thickness of 3 mm or more and 40 mm or less. The absorbent auxiliary sheet according to any one of claims 1 to 8, on an absorbent layer made of a non-woven fabric obtained by heat-treating an air-laid web composed of raw material fibers having a cellulose fiber content of 5 mass% to 98 mass%. Absorber with laminated layers.

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