JP2013150799A - Nonwoven-fabric sheet for absorber and absorbent article containing the nonwoven-fabric sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven-fabric sheet for an absorber, which has excellent strength, liquid permeability, and liquid-diffusion performance.SOLUTION: This nonwoven-fabric sheet for an absorber contains 20-40 mass parts of beaten pulp (a) and 10-70 mass parts of regenerated cellulose (b), and has density of 50-280 mg/cm, wherein the beaten pulp (a) is fibrillated and has a weight-weighted mean fiber length in the range of 1.0 and 5.0 mm.

Description

  The present disclosure relates to a nonwoven fabric sheet for an absorbent body and an absorbent article including the nonwoven fabric sheet.

  Absorbent articles, such as disposable diapers, sanitary napkins, panty liners, etc., have improved basic performance due to technological development that has been accumulated over many years. In addition, leaks and the like are less likely to occur, and research on further enhancement of functionality is now ongoing.

  The absorbent article is generally composed of a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body between the liquid-permeable top sheet and the liquid-impermeable back sheet. Absorber, especially its core wrap, has a function to retain internal superabsorbent polymer particles both when dry and wet, by rapidly diffusing blood that reaches the absorbent article to a wide area of the absorber A function to absorb quickly is required.

For example, in Patent Document 1, in a substantially longitudinal absorbent article having a liquid-permeable surface material, a liquid-retaining absorbent, and a liquid-impermeable leak-proof material, the absorbent is diffusible. And (a) the diffusible absorbent sheet has a hydrophilicity (cos θ) of 0.5 to 1 and has a longitudinal Clem water absorption. (B) The absorption retention sheet is a sheet composed of a fiber assembly having a capillary osmotic pressure of 4000 to 15000 [dyn / cm ² ], and is a physiological saline solution. A high-absorption polymer having an absorption rate of 40 to 70 [g / g] and an absorption rate of 2 [ml / 0.3 g polymer · min] or more is sandwiched by 10 to 100% by weight with respect to the fiber assembly. It consists of laminated sheets Osamusei article is described (claim 1).

  Patent Document 1 also discloses that the diffusible absorbent sheet is a wet nonwoven fabric made of hydrophilic fibers (Claim 2), and is a mixed paper of rayon fibers and pulp fibers, and the rayon fibers are less than 3 denier. And the mixing ratio in the mixed paper is 30 to 90% (Claim 7).

Patent Document 2 describes that a diffusion layer can be provided between the surface layer and the portion having the superabsorbent polymer in order to improve the diffusibility of the absorbent article. In Patent Document 2, as the diffusion layer, a fiber aggregate (absorption of 100 mm or more, particularly 150 mm or more) of a Krem water absorption according to “Water absorption test method by paper and paperboard Krem method” defined in JIS P 8141 in 10 minutes. Paper, etc.) can be used. Patent Document 2 also discloses that the diffusion layer is made of a synthetic fiber (rayon fiber or the like) having a hydrophilic surface, or both a synthetic fiber (rayon fiber or the like) and a cellulose fiber (pulp fiber or the like) having a hydrophilic surface. It is possible to use a fiber assembly sheet that is made of fibers, has a basis weight of 30 to 100 g / m ² , and has a Klem water absorption of 100 mm or more after 10 minutes with physiological saline as defined in JIS P 8141. Have been described.

JP-A-4-89053 JP 2004-298384 A

However, in the absorbent body described in Patent Document 1, in order to maintain the strength of the diffusible absorbent sheet, each fiber is bonded using polyvinyl alcohol or the like as a binder, or the fibers are bonded together by a spunbond method. Since it is formed by fusing, liquid diffusibility may be inhibited.
In addition, the diffusion layer described in Patent Document 2 is designed in consideration of the diffusibility of absorbed body fluid or the like, but is not designed in consideration of strength and liquid permeability.

For example, the core wrap of the absorber is not only diffusible in the plane direction, but also has excellent liquid permeability in the thickness direction, so that the absorbed body fluid is quickly diffused in the plane direction while being rapidly diffused to the inside, It is considered that the body fluid can be trapped inside the absorber more quickly. Further, for example, it is considered that the core wrap is excellent in strength, more specifically, wet strength, so that the internal superabsorbent polymer and the like can be held without leaking.
Therefore, an object of this invention is to provide the nonwoven fabric sheet for absorbers which is excellent in intensity | strength, liquid permeability, and liquid diffusibility.

As a result of intensive studies to solve the above-described problems, the present disclosure includes beaten pulp (a) and regenerated cellulose (b) in a ratio of 20 to 40 parts by mass and 10 to 70 parts by mass, respectively. A nonwoven sheet for an absorbent body, wherein the beaten pulp (a) is fibrillated and has a weight-weighted average fiber length in the range of 1.0 to 5.0 mm, and the nonwoven sheet is 50 to It has been found that the above-mentioned problems can be solved by a nonwoven fabric sheet characterized by having a density of 280 mg / cm ³ .

  The nonwoven fabric sheet for an absorbent body of the present disclosure is excellent in strength, liquid permeability, and liquid diffusibility.

FIG. 1 is a diagram showing the relationship between the density of a nonwoven fabric sheet and the liquid absorption height in Example 4.

Hereinafter, the nonwoven fabric sheet for an absorbent body of the present disclosure will be described in detail.
The nonwoven fabric sheet for absorbent bodies of the present disclosure (hereinafter, the nonwoven fabric sheet for absorbent bodies of the present disclosure may be referred to as “nonwoven fabric sheet of the present disclosure” and “nonwoven fabric sheet”) is beaten pulp (a) and And regenerated cellulose (b) in a ratio of 20 to 40 parts by mass and 10 to 70 parts by mass, respectively.

  The beaten pulp (a) is fibrillated, and in this specification, “fibrillated” means that a microfiber portion having a submicron-sized fiber diameter is partially peeled from the surface of a fiber main body portion. And it means extending from the surface of the main body portion of the fiber.

The beating pulp (a) can be formed by free beating or sticking beating the pulp. Specifically, the beaten pulp (a) can be formed by, for example, stirring the unbeaten pulp with water in a mixer, passing the unbeaten pulp through a pulper, a disc refiner, a beater, or the like. it can.
The beaten pulp (a) is preferably fibrillated, that is, fluffed, without changing the fiber length so much in both free beating and viscous beating. This is because if the fiber length is shortened, the nonwoven fabric sheet for absorbent bodies of the present disclosure tends to be paper-like (hard).

  There are several means for specifying the beaten pulp (a). One of them is to evaluate the weight-weighted average fiber length distribution (mass distribution) of the main body portion and the microfiber portion in the beaten pulp (a). Since the length distribution of the microfiber portion appears in a place shorter than the fiber length distribution of the main body portion, the main body portion and the microfiber portion can be obtained by examining the fiber length distribution of the entire beat pulp (a). It is possible to know the weight-weighted average fiber length distribution. Another means for specifying the beaten pulp (a) is to evaluate the beating degree of the beaten pulp (a). As the fibrillation progresses, that is, the beating progresses, the beating degree tends to decrease.

The weight-weighted average fiber length distribution can be measured as described in JP-A No. 2001-288658. The weight-weighted average fiber length distribution can be measured using a Kajaani fiber lab fiber length measuring instrument manufactured by Metso Automation.
The said beating degree is synonymous with "Canada standard freeness", and can be measured according to "3 (1) Canadian standard freeness test method" of JIS P 8121: 1995, pulp freeness test method. .

The general procedure of the “3 (1) Canadian Standard Freeness Test Method” is as follows.
(1) Attach the drain tube to the arm of the support base, close the lower lid, and open the air cock on the upper lid.
(2) Place the graduated cylinder in a position where it can receive drainage from the side pipe.
(3) Weigh accurately 1000 mL of sample into a 1000 mL graduated cylinder.
(4) Gently pour the contents of the female scinder into the drain.
(5) Five seconds after putting the sample, the air cock is opened to let the sample flow down.
(6) When drainage of the side pipe stops, read the amount of drainage from the side pipe.
(7) The amount of drainage is corrected to a standard concentration of 0.30% and a standard temperature of 20 ° C. according to the correction table (Appendix Tables 1 and 2), and this is the Canadian standard freeness, that is, the beating degree.

  The beaten pulp (a) is fibrillated and has a body portion and a microfiber portion extending from the body portion, and as a whole preferably ranges from about 1.0 to about 5.0 mm, more preferably about It has a weight-weighted average fiber length in the range of 1.5 to about 4.0, and more preferably in the range of about 2.0 to about 3.5. When the weighted average fiber length is less than about 1.0 mm, the fiber length becomes short, the nonwoven fabric sheet for absorbent bodies of the present disclosure tends to be paper-like (hard), and the weighted average fiber length is about If it exceeds 5.0 mm, the fibers of the pulp before fibrillation are long, and the fibers of the pulp may be entangled when fibrillated.

  The “weight-weighted average fiber length” can be measured by the above-mentioned Kajaani fiber lab fiber length measuring instrument, and is a value represented by L (w).

  In the present specification, the microfiber part relating to the beaten pulp (a) means a fiber having a length of 1 mm or less, and based on the weight of the beaten pulp (a), the proportion of the microfiber part is preferably about 17 to It is in the range of about 65% by weight, more preferably in the range of about 20 to about 60% by weight, and even more preferably in the range of about 23 to about 55% by weight. When the proportion of the microfiber portion is below the above-mentioned range, the fiber entanglement in the nonwoven fabric sheet for an absorbent body of the present disclosure, in particular, the microfiber portion of the beaten pulp (a) and other microfiber portions or other fibers There is a tendency for the entanglement to decrease and the strength of the nonwoven fabric sheet, especially the wet strength, to decrease, and when the ratio of the microfiber portion exceeds the above range, the length of the main body portion is shortened, and the nonwoven fabric sheet is also wetted. There is a tendency for strength to decrease.

  In the present specification, the ratio of the microfiber portion is the “weight line weight length distribution” “center line fiber length distribution” Fr (w) obtained by the above-mentioned Kajaani fiber lab fiber length measuring instrument. The ratio (mass%) of the fiber in the range of 0.00 to 1.00 mm.

  The beating pulp (a) preferably has a beating degree of about 400 to about 650 mL, and more preferably has a beating degree of about 400 to about 600 mL. Although the wet strength of the nonwoven fabric sheet can be increased by proceeding beating (decreasing the value of the beating degree), when the beating progresses, the nonwoven sheet becomes paper-like and the texture tends to decrease. When the beating degree is high, the entanglement between the fibers becomes insufficient, and the strength, particularly the wet strength, tends to decrease.

The weight-weighted average fiber length distribution and beating degree of beating pulp (a) can be adjusted by the type of equipment used for beating, the processing time, and the like.
Examples of the raw material of the beaten pulp (a) include wood pulp such as softwood pulp and hardwood pulp, manila hemp, linder pulp, bamboo pulp, kenaf and the like.

The regenerated cellulose (b) is not particularly limited, and examples thereof include viscose rayon and copper ammonia rayon. The nonwoven fabric sheet for absorbent bodies of this indication can contain 1 type, or 2 or more types of regenerated cellulose (b).
The average fiber length of regenerated cellulose (b) is preferably about 3 to about 13 mm, and more preferably about 5 to about 11 mm. When the average fiber length becomes long, it becomes difficult to maintain the texture of the nonwoven fabric, and when the average fiber length becomes short, the interlace between fibers becomes insufficient and the strength of the nonwoven fabric tends to decrease.

  The fineness of regenerated cellulose (b) is preferably from about 0.6 to about 1.7 dtex, and more preferably from about 0.8 to about 1.4 dtex. When the fineness is small, the production cost of regenerated cellulose (b) tends to increase, and the spinning quality tends to be unstable. When the fineness is large, fiber entanglement is less likely to occur and the strength tends to decrease. .

The nonwoven sheet of the present disclosure comprises beaten pulp (a) and regenerated cellulose (b) in a ratio of about 20 to about 40 parts by weight and about 10 to about 70 parts by weight, respectively, and preferably about 25 to about 35. And in a ratio of about 15 to about 65 parts by weight.
The beaten pulp (a) has a high degree of hydrogen bonding with other fibers because the microfiber portion extends from the surface of the main body portion of the pulp fiber, and imparts high dry strength to the nonwoven fabric sheet of the present disclosure. Can do. Moreover, since the microfiber part extended from the surface of the main-body part of a pulp fiber tends to be entangled with the fiber of other microfiber parts or other fibers, for example, the fiber of regenerated cellulose (b), it is highly wetted in the nonwoven fabric sheet of this indication. Strength can be imparted.

  Moreover, in the nonwoven fabric which consists only of regenerated cellulose (b), when a liquid is absorbed, the fiber of regenerated cellulose (b) will swell, the space | gap between fibers will become small, and there exists a tendency for liquid permeability to be inferior. By combining the regenerated cellulose (b) with the beaten pulp (a) having irregularities on the surface, even when the liquid is absorbed, the gap between the fibers can be secured, and the liquid permeability An excellent nonwoven sheet can be formed.

  As the ratio of the beaten pulp (a) increases, both the dry strength and the wet strength tend to increase. However, since the voids in the nonwoven fabric sheet are filled with the microfiber portion and the voids are reduced, the liquid permeability Tend to be inferior. Moreover, when the ratio of the beating pulp (a) is low, the degree of hydrogen bonding and the degree of entanglement of the nonwoven fabric sheet are lowered, so that the strength tends to be lowered.

The nonwoven sheet of the present disclosure has a density of about 50 to about 280 mg / cm ³ and preferably has a density of about 60 to about 200 mg / cm ³ . Since the nonwoven fabric sheet of the present disclosure has a density within the above range, a capillary tube suitable for diffusing the absorbed liquid can be formed between the fibers in the nonwoven fabric sheet. It is thought that it is excellent in property. When the density is increased, voids in the nonwoven fabric sheet are decreased, and it is considered that liquid diffusibility is inferior because it is difficult to form capillaries, and when the density is decreased, the voids in the nonwoven fabric sheet increase, but the capillary phenomenon Thus, it is difficult to quickly transfer the absorbed liquid, so that it is considered that the liquid diffusibility is poor and the strength of the nonwoven fabric sheet is weakened.

The density can be calculated by dividing the basis weight of the nonwoven fabric sheet by its thickness. The basis weight measurement method will be described later.
The thickness of the nonwoven fabric sheet can be measured using THICKNESS GAUGE UF-60 manufactured by Daiei Kagaku Seiki Seisakusho. In UF-60, the diameter of a measurement surface is 44 mm, the pressure of 0.3 kPa is applied to a nonwoven fabric sheet, and the thickness is measured.

  In addition, the density of a nonwoven fabric sheet can be adjusted by changing water jet processing conditions, drying conditions, etc., for example, when a nonwoven fabric sheet is a wet spunlace nonwoven fabric. For example, when the water pressure during water jet treatment is increased, the density of the nonwoven fabric sheet can be increased, and in drying using a Yankee dryer, a pressure-bonded state is formed between the dryer cylinder and the blanket on one side. The density of the nonwoven fabric sheet can be increased.

In another embodiment of the nonwoven fabric sheet for absorbent bodies of the present disclosure, the nonwoven fabric sheet for absorbent bodies further comprises unbeaten pulp (c). Examples of the unbeaten pulp (c) include pulp that has not been free beaten or viscous beaten, that is, unbeaten pulp.
Examples of the unbeaten pulp (c) include wood pulp such as softwood pulp and hardwood pulp, Manila hemp, Linder pulp, bamboo pulp, kenaf and the like. Examples of the softwood pulp include softwood bleached kraft pulp. Unbeaten pulp (c) may be the same as the material of beating pulp (a), or may be a different material.

The unbeaten pulp (c) preferably has a beating degree of about 700 to about 800 mL. This is to provide bulkiness and flexibility to the nonwoven fabric of the present disclosure.
In the above embodiment, the nonwoven sheet of the present disclosure preferably contains unbeaten pulp (c) in an amount of about 5 to about 70% by weight, and about 10 to about 60% by weight, based on the weight of the nonwoven sheet. More preferably, it is included in an amount of%.

  When a nonwoven fabric sheet contains unbeaten pulp (c) in the said range, a nonwoven fabric sheet can have high dry strength and liquid diffusibility. This is because unbeaten pulp (c) can impart dry strength to the nonwoven fabric sheet, but has little microfiber portion and therefore has a low degree of entanglement and does not significantly affect the strength when wet. .

  In embodiments where the absorbent nonwoven sheet comprises unbeaten pulp (c), the nonwoven sheet comprises from about 20 to about 40% by weight of beaten pulp (a) and from about 10 to about 70% by weight of regenerated cellulose (b). Preferably about 5 to about 70% by weight of unbeaten pulp (c), and about 20 to about 40% by weight of beaten pulp (a), about 15 to about 65% by weight of regenerated cellulose (b), It is preferable to contain about 10 to about 60 mass% of unbeaten pulp (c). This is from the viewpoint of strength, liquid permeability and liquid diffusibility.

The nonwoven sheet of the present disclosure preferably has a basis weight of about 15 to about 100 g / m ² , more preferably has a basis weight of about 20 to about 90 g / m ² , and about 30 to about 80 g / m 2. More preferably, it has a basis weight of ² . When the basis weight is less than about 15 g / m ² , when the nonwoven fabric is used as a core wrap of an absorbent body, tearing may occur at the time of wearing, and a material such as a super absorbent polymer may leak out. There is. Moreover, when the said basic weight exceeds about 100 g / m < ² >, there exists a tendency for liquid permeability to fall.

The basis weight can be measured as follows.
Ten samples having a size of 100 mm × 100 mm were taken, the mass of each sample was measured, and then the mass (g) of each sample was divided by the area (m ² ) of each sample, thereby obtaining the basis weight of each sample. Calculate the amount. The average value of the basis weight of a total of 10 samples is calculated and the average value is adopted as the basis weight.

The nonwoven fabric sheet of the present disclosure has a liquid permeation time in a liquid permeability test of preferably about 110 seconds or less, more preferably about 100 seconds or less, and even more preferably about 90 seconds or less.
When the liquid permeation time is in the above range, a liquid such as a body fluid that has reached the absorbent article can be quickly transmitted in the thickness direction of the absorbent body, that is, the inside thereof, together with high liquid diffusibility. The liquid can be quickly trapped inside the absorber.

The liquid permeability test can be performed as follows.
(1) Prepare a liquid-impervious lower plate having a size of 106 mm × 106 mm × 3 mm (length × width × thickness), make a hole with a diameter of 1 mm, four vertices of a square with a side of 11 mm, and the square It is provided at a total of five locations, one at the center. The hole is provided so that the center of the lower plate coincides with the center of the square. The lower plate is previously wetted with artificial urine.
(2) A sample having a size of 100 mm × 100 mm is prepared, and placed on the lower plate so that the center of the sample and the center of the lower plate coincide.

(3) A silicon rubber packing having an outer diameter of 50 mm, an inner diameter of 40 mm, and a thickness of 3 mm is prepared, and the silicon rubber packing is placed on the sample so that the center of the lower plate coincides with the center of the silicon rubber packing. Put.
(4) A weight (total mass: 2 kg) having a cylindrical portion (inner diameter: 30 mm) for dropping artificial urine on the silicon rubber packing, the center of the lower plate exists on the central axis of the cylindrical portion Put to do.

(5) From the cylindrical portion, 100 mL of artificial urine is dropped onto the sample, and the time from the start of dropping until the artificial urine on the upper surface of the sample disappears is measured. More precisely, it is determined that the artificial urine has disappeared when the artificial urine is no longer present within a radius of 14 mm around the point intersecting the central axis of the cylindrical portion on the upper surface of the sample.
(6) The above experiment is repeated 5 times, and the average value is defined as the liquid permeation time.

  The above test is performed at 20 ° C. The artificial urine can be prepared by dissolving 200 g of urea, 80 g of sodium chloride, 8 g of magnesium sulfate, 3 g of calcium chloride, and about 1 g of pigment: Blue No. 1 in 10 L of ion-exchanged water.

In the water absorption test, the nonwoven sheet of the present disclosure preferably has a liquid absorption height of about 120 mm or more, more preferably has a liquid absorption height of about 125 mm or more, and more preferably has an absorption height of about 130 mm or more. Has a liquid height. In addition, the nonwoven fabric sheet of the present disclosure preferably has a water absorption ratio of about 2.0 times or more, more preferably about 2.2 times or more in a water absorption test, and more preferably about 2.2 times. Has a water absorption ratio of 2.4 times or more.
When the liquid absorption height and the water absorption ratio are in the above ranges, the liquid such as body fluid that has reached the absorbent article can be quickly diffused in the plane direction of the absorbent body, along with the high liquid permeability, Liquid can be quickly trapped inside the absorber.

In this specification, a water absorption test can be measured based on the water absorption test method by the Krem method of JIS P 8141: 2004, and the specific procedure is as follows.
(1) A sample is cut into a size of 230 mm × 25 mm (length × width), and its initial mass (W ₀ ) is measured.
(2) The artificial urine is filled to a height of 35 mm in a rectangular parallelepiped immersion container of 170 mm × 90 mm × 40 mm (length × width × depth). The composition of the artificial urine is as described in the above-mentioned “liquid permeability test”.

(3) The sample is fixed to a hanging tool, and the end in the length direction, 30 mm, is immersed in artificial urine and left for 5 minutes.
(4) After 5 minutes, the height at which the artificial urine rose is measured.
(5) Next, the sample is removed from the suspending tool, a portion of 30 mm in length that has been immersed in artificial urine is cut, and the mass (W ₁ ) of the sample is measured.
(6) The absorption magnification (X) is calculated according to the following formula.
X = {(W ₁ × 230/200) −W ₀ } / W ₀
(7) The above experiment is repeated 5 times and the average value is adopted.

  The nonwoven fabric sheet of the present disclosure has a tensile strength per 25 mm width in the conveying direction of preferably about 7N or more, more preferably about 9N or more, and even more preferably about 12N or more when dried. In this specification, the tensile strength per 25 mm width in the conveying direction during drying is simply referred to as “dry strength”, and the unit may be represented by “N / 25 mm”.

  Moreover, the nonwoven fabric sheet of the present disclosure has a tensile strength per 25 mm width in the conveying direction of preferably about 0.7 N or more, more preferably about 2.0 N or more when wet, and more preferably about 2.0 N or more. It is 4.0N or more. In this specification, the tensile strength per 25 mm width in the conveying direction when wet is simply referred to as “wet strength”, and the unit may be represented by “N / 25 mm”.

  It is preferable that the dry strength is within the above range from the viewpoint of wearing the absorbent article and manufacturing the absorbent article. Moreover, when the wet strength is in the above range, even when body pressure is applied at the time of wearing, the pulp, the superabsorbent polymer, and the like inside the absorbent body are difficult to leak out.

  For the dry strength, a sample cut to a width of 25 mm and a length of 150 mm was left to dry for 24 hours under conditions of 20 ° C. and a relative humidity of 65%, and then the sample in the dry state was subjected to Tensilon-type tension. It means the tensile force (N) at break when measured with a tester at a chuck interval of 100 mm and a tensile speed of 200 mm / min. The dry strength can be measured using, for example, an Instron model 5564 tester.

The above-mentioned wet strength is obtained by immersing a sample cut to a width of 25 mm × a length of 150 mm in distilled water for 5 minutes and then leaving it on the wire mesh for 1 minute under the conditions of 20 ° C. and 65% relative humidity atmosphere. It means the tensile force (N) at break when measured with a Tensilon type tensile tester at a chuck interval of 100 mm and a tensile speed of 200 mm / min. The wet strength can be measured using, for example, an Instron model 5564 tester.
As the dry strength and wet strength, an average value of five measurements can be adopted.

  The nonwoven fabric sheet of the present disclosure is excellent in strength, liquid permeability, and liquid diffusibility without containing a binder. However, in another embodiment of the nonwoven fabric sheet of the present disclosure, the nonwoven fabric described above is used to further increase wet strength and the like. The sheet may contain a binder.

  Examples of the binder include alkyl celluloses such as carboxymethyl cellulose, methyl cellulose, ethyl cellulose and benzyl cellulose, polyvinyl alcohol, modified polyvinyl alcohol containing a predetermined amount of a sulfonic acid group or a carboxyl group, polyamide epichlorohydrin and the like. The binder can be applied to a fiber web or a nonwoven fabric sheet using a silk screen or the like. In the case where the binder is water-swellable or water-insoluble, the binder can be mixed during the production of the fibrous web of the nonwoven sheet.

  The manufacturing method of the nonwoven fabric sheet of the present disclosure is not particularly limited. For example, a fiber web containing beaten pulp (a), regenerated cellulose (b), and unbeaten pulp (c) as desired is formed by a wet method. Then, the fiber web can be formed by subjecting it to water jet treatment and drying.

  The nonwoven fabric sheet for an absorbent body of the present disclosure can be used for a core wrap of the absorbent body, a diffusion sheet inside the absorbent body, and the like.

Hereinafter, although an example is given and this indication is explained, this indication is not limited to these examples.
[Example 1]
Disperse 2.64 g of beating pulp (a ₁ ) and 6.16 g of viscose rayon made by Daiwabo Rayon as regenerated cellulose (b) in a water bath of 400 mm × 400 mm × 400 mm (width × depth × height). The fiber web 1 was formed on an 80-mesh mesh sheet. The beaten pulp (a ₁ ) is unbeaten pulp (c ₁ ) (weight-weighted average fiber length, L (w) measured by the above-mentioned Kajaani Fiber Lab fiber length measuring instrument is 2.81 mm, And similarly, the ratio of the microfiber part was 11.6 mass%, and the beating degree was about 730 mL, and it manufactured by fibrillating using a disc refiner.

In the beaten pulp (a ₁ ), the weight-weighted average fiber length, L (w), measured by the above-mentioned Kajaani Fiber Lab fiber length measuring device is 2.79 mm, and the ratio of the microfiber portion is 25 0.8% by mass and the beating degree was 600 mL. The viscose rayon had an average fiber length of about 7 mm and a fineness of about 1.1 Dtex.

The fiber web 1 is subjected to a water jet treatment (speed: 30 m / min, treatment pressure: 2 MPa × 1 time + 6 MPa × 3 times), and then dried with a Yankee dryer (speed: 1.5 m / min, temperature: 135 ° C.). Thereby, the nonwoven fabric sheet 1 was formed. Table 1 shows the basis weight, thickness, density, liquid absorption height, water absorption magnification, and physical properties of the nonwoven fabric sheet 1.
The thickness, density, liquid absorption height, water absorption magnification, and physical properties were measured according to the methods defined in this specification. Moreover, in Table 1, MD means the conveyance direction at the time of manufacture.

[Examples 2 and 3 and Comparative Examples 1 to 4]
Except for changing the composition as shown in Table 1, according to Example 1, the nonwoven sheet No. 2-7 were formed. The unbeaten pulp (c ₁ ) in Table 1 is the same as the unbeaten pulp (c ₁ ) that is the raw material of the beat pulp (a ₁ ) in Example 1, and is softwood bleached kraft pulp NBKP.
Nonwoven sheet No. Table 1 shows the basis weight, thickness, density, liquid absorption height, water absorption magnification, dry strength, and wet strength of 2 to 7.

The nonwoven fabric sheets No. 1 to 3 of Examples 1 to 3 are excellent in “liquid permeability” because the liquid permeation time is 110 seconds or less, the liquid absorption height is 120 mm or more, and the water absorption magnification is 2.0 times. From the above, it can be seen that the “liquid diffusibility” is excellent, and the dry strength is 7.0 N / 25 mm or more and the wet strength is 0.7 N / 25 mm or more, so that “strength” is excellent.
Non-woven fabric sheet No. 4 consisting only of regenerated cellulose (b) is excellent in liquid permeability, liquid diffusibility and strength, but its hydrogen bonding force is weak, so the gap between fibers becomes large due to friction, shear, etc. In addition, the pulp inside the absorbent body, the superabsorbent polymer, etc. are likely to leak and are inferior in practicality.
Nonwoven sheet No. 1 consisting only of unbeaten pulp (c) 5 and a nonwoven fabric sheet No. 1 made of regenerated cellulose (b) and unbeaten pulp (c). 6 is inferior in liquid permeability.

[Example 4]
Nonwoven fabric sheets 8 to 11 having different densities were manufactured by changing the degree of contact of the blanket when heating the fiber web 1 in Example 1 with a Yankee dryer. Similarly, nonwoven fabric sheets 12-15 having different densities were produced from the fiber web 2 in Example 2, and nonwoven fabric sheets 16-18 having different densities were produced from the fiber web 3 in Example 3. In addition, the nonwoven fabric sheets 11, 15, and 18 are the same as the nonwoven fabric sheets 1, 2, and 3, respectively. The above-mentioned liquid absorption height was measured regarding the nonwoven fabric sheets 8-18. The results are shown in Table 2 below, and the relationship between density and liquid absorption height is shown in FIG.

As apparent from Table 2 and FIG. 1, the liquid absorption height tends to increase as the density of the nonwoven fabric sheet decreases. If the density is approximately 280 mg / cm ³ or less, the liquid absorption height is 120 mm or more. It can be seen that it has excellent diffusibility.

The present disclosure relates to the following aspects.
[Aspect 1]
A non-woven fabric sheet for an absorbent comprising beaten pulp (a) and regenerated cellulose (b) in a ratio of 20 to 40 parts by mass and 10 to 70 parts by mass, respectively.
Beating pulp (a) is fibrillated and has a weight-weighted average fiber length in the range of 1.0 to 5.0 mm, and the nonwoven sheet has a density of 50 to 280 mg / cm ³ ,
The said nonwoven fabric sheet characterized by the above-mentioned.

[Aspect 2]
Beating pulp (a) has a main-body part and the microfiber part extended from the said main-body part, The ratio of the said microfiber part is the range of 17-65 mass% with respect to the mass of beating pulp (a). The nonwoven fabric sheet according to Aspect 1 in
[Aspect 3]
The nonwoven fabric sheet according to aspect 1 or 2, wherein the beating pulp (a) has a beating degree of 400 to 650 mL.

[Aspect 4]
The nonwoven fabric sheet as described in any one of aspects 1-3 which further contains unbeaten pulp (c) in the quantity of 5-70 mass% with respect to the mass of the said nonwoven fabric sheet.
[Aspect 5]
The nonwoven fabric sheet according to aspect 4, wherein the unbeaten pulp (c) has a beating degree of 700 to 800 mL.

[Aspect 6]
The beat pulp (a) 20 to 40% by mass, regenerated cellulose (b) 10 to 70% by mass, and unbeaten pulp (c) 5 to 70% by mass, according to any one of aspects 1 to 5 Nonwoven sheet.
[Aspect 7]
It has a basis weight of 15 to 100 / m ^2, the nonwoven fabric sheet according to any of aspects 1-6.

[Aspect 8]
The nonwoven fabric sheet according to any one of aspects 1 to 7, wherein the liquid permeation time in the liquid permeability test is 110 seconds or less.
[Aspect 9]
The nonwoven fabric sheet according to any one of aspects 1 to 8, wherein in the water absorption test, the liquid absorption height is 120 mm or more and the water absorption magnification is 2.0 or more.

[Aspect 10]
The nonwoven fabric sheet according to any one of aspects 1 to 9, wherein the tensile strength per 25 mm width in the conveying direction is 7N or more when dried and 0.7N or more when wet.
[Aspect 11]
An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body between the liquid-permeable top sheet and the liquid-impermeable back sheet,
The absorbent body includes the nonwoven fabric sheet according to any one of aspects 1 to 10.
The above absorbent article.
[Aspect 12]
The absorbent article according to aspect 11, wherein the nonwoven fabric sheet forms a core wrap of the absorbent body.

Claims (12)

A non-woven fabric sheet for an absorbent comprising beaten pulp (a) and regenerated cellulose (b) in a ratio of 20 to 40 parts by mass and 10 to 70 parts by mass, respectively.
Beating pulp (a) is fibrillated and has a weight-weighted average fiber length in the range of 1.0 to 5.0 mm, and the nonwoven sheet has a density of 50 to 280 mg / cm ³ ,
The said nonwoven fabric sheet characterized by the above-mentioned.   Beating pulp (a) has a main-body part and the microfiber part extended from the said main-body part, The ratio of the said microfiber part is the range of 17-65 mass% with respect to the mass of beating pulp (a). The nonwoven fabric sheet according to claim 1.   The nonwoven fabric sheet according to claim 1 or 2, wherein the beaten pulp (a) has a beating degree of 400 to 650 mL.   The nonwoven fabric sheet as described in any one of Claims 1-3 which further contains unbeaten pulp (c) in the quantity of 5-70 mass% with respect to the mass of the said nonwoven fabric sheet.   The nonwoven fabric sheet according to claim 4, wherein the unbeaten pulp (c) has a beating degree of 700 to 800 mL.   The beaten pulp (a) 20 to 40% by mass, the regenerated cellulose (b) 10 to 70% by mass, and the unbeaten pulp (c) 5 to 70% by mass according to any one of claims 1 to 5. The nonwoven fabric sheet as described. The nonwoven fabric sheet as described in any one of Claims 1-6 which has a basic weight of 15-100 g / m < ² >.   The nonwoven fabric sheet as described in any one of Claims 1-7 whose liquid permeation | transmission time in a liquid-permeability test is 110 second or less.   The nonwoven fabric sheet as described in any one of Claims 1-8 whose liquid absorption height is 120 mm or more and a water absorption magnification is 2.0 times or more in a water absorption test.   The nonwoven fabric sheet according to any one of claims 1 to 9, wherein the tensile strength per 25 mm width in the conveying direction is 7N or more when dry and 0.7N or more when wet. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorbent body between the liquid-permeable top sheet and the liquid-impermeable back sheet,
The absorber includes the nonwoven fabric sheet according to any one of claims 1 to 10,
The absorbent article.   The absorptive article according to claim 11 in which said nonwoven fabric sheet forms core wrap of said absorber.

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