JP2020156669A - Nonwoven fabric for absorbent article - Google Patents

Abstract

To provide a nonwoven fabric for an absorbent article capable of achieving both of thinning of an absorber and liquid return reduction in the absorbent article, since, thinning is desired for improving wearing comfort, and as a technique for thinning the absorbent article, an amount of pulp fibers included in the absorber is reduced, or a high absorbent polymer material is held by a nonwoven fabric and making the material a sheet without a pulp fiber, however, due to thinning of the absorbent article, gel blocking by the high absorbent polymer material (called as SAP) in liquid absorption time easily occurs, and by excessive gel blocking, absorption performance is reduced and liquid return (wet back) easily occurs sometimes.SOLUTION: There is provided a nonwoven fabric for an absorbent article which has hydrophilic property and which includes a layer of long fibers whose average fiber diameter is 1 μm or smaller.SELECTED DRAWING: None

Description

The present invention relates to non-woven fabrics for absorbent articles such as sanitary napkins and panty liners.

Various proposals have been made for improving liquid absorbency and wearing feeling in absorbent articles such as sanitary napkins.
For example, Patent Document 1 describes a technique for including a highly absorbent polymer in a long fiber web from the viewpoint of preventing gel blocking in an absorber and improving the liquid absorption rate. The absorbent article described in Patent Document 2 describes a technique for fixing a highly absorbent material in the form of particles by melt bonding between microfibers from the viewpoint of increasing wet strength. Further, Patent Document 3 describes an absorbent article provided with an absorbent core including an elastic web and an accommodating layer having pores in order to maintain a fixed state between layers. The document describes that the absorbent core has a melt blown fiber web and superabsorbable material particles.

JP-A-2007-144101 Special Table 2007-512868A Japanese Patent Publication No. 7-502433

Absorbent articles are desired to be thinner in order to improve wearing comfort. As a technique for reducing the thickness, the number of pulp fibers contained in the absorber has been reduced, and a highly absorbent polymer material has been sandwiched between non-woven fabrics to form a sheet without using pulp fibers. However, due to the thinning, gel blocking by a highly absorbent polymer material (also referred to as SAP) is likely to occur during liquid absorption. If gel blocking progresses excessively, the absorption performance may deteriorate and liquid return (wetback) may easily occur.

In view of the above points, the present invention relates to a non-woven fabric for an absorbent article, which can achieve both thinning of the absorber and reduction of liquid return in the absorbent article.

The present invention provides a non-woven fabric for an absorbent article that is hydrophilic and contains a layer of long fibers having an average fiber diameter of 1 μm or less.

The non-woven fabric for absorbent articles of the present invention can achieve both thinning of the absorber and reduction of liquid return in the absorbent article.

Hereinafter, preferred embodiments of the non-woven fabric for absorbent articles of the present invention will be described.
The non-woven fabric for absorbent articles of the present invention is hydrophilic and contains a layer of long fibers having an average fiber diameter of 1 μm or less. Here, the term "long fiber" has a general meaning, and includes, for example, a fiber having a fiber aspect ratio (fiber length / diameter) of 1000 or more and a fiber length of 1 mm or more. In general, a non-woven fabric produced by a method of spinning continuous fibers such as melt spinning, dry spinning, and wet spinning falls under the category of "long fiber layer". Further, "a layer of long fibers that is hydrophilic and has an average fiber diameter of 1 μm or less" means that the average fiber diameter of the hydrophilic long fibers contained in the layer is 1 μm or less, and is included in the layer. It does not mean that the average fiber diameter of all the fibers is 1 μm or less.
The layer of long fibers having an average fiber diameter of 1 μm or less, which is hydrophilic, has a dense liquid flow path between the fibers (for example, a liquid flow path on the order of nanometers) and has high liquid absorption. Further, the layer of long fibers is less likely to lose its shape when wet than the layer of short fibers having a fiber length of less than 1 mm. That is, the strength when wet is high, and the layer shape is easily maintained. In addition, in the layer of the long fibers, the long fibers are undulated but oriented in the direction of the fiber length to form a layer, and the non-woven fabric has a unidirectional fiber orientation when viewed locally. Be prepared. As a result, the above-mentioned dense liquid flow path is streaked. The streaky liquid flow paths cooperate with each other through ultrafine long fibers while being close to each other in a thin non-woven fabric to form a dense and complicated three-dimensional void structure (liquid flow path network structure).
As a result, the non-woven fabric for absorbent articles of the present invention has high liquid absorbency and high shape retention, and the liquid once absorbed is difficult to be discharged to the outside. Specifically, the non-woven fabric for absorbent articles of the present invention draws the liquid into a dense liquid flow path between the fibers while diffusing the liquid in the fiber length direction of the long fibers. At the same time, the liquid flow path forming the above-mentioned three-dimensional void structure can serve as a storage gap (for example, a storage gap on the order of nanometers) to hold the liquid. The absorbed and retained liquid tends to form a stable liquid film in the dense and streaky storage gap extending in the fiber length direction, and is difficult to be discharged to the outside.
Such a non-woven fabric for an absorbent article of the present invention can be included as a liquid-retaining member in an absorber in the absorbent article. As a result, the absorber according to the present invention has high liquid absorbency instead of pulp fiber or a highly absorbent polymer material, and both thinning and reduction of liquid return can be realized.

From the viewpoint of enhancing liquid absorption, the average fiber diameter of the long fibers is preferably 1 μm or less, more preferably 0.9 μm or less, still more preferably 0.8 μm or less. The smaller the average fiber diameter of the long fibers is, the more preferable, but from the viewpoint of the liquid absorption rate, 0.05 μm or more is preferable, 0.1 μm or more is more preferable, and 0.2 μm or more is further preferable.
The fiber length of the long fibers is preferably 1 mm or more, more preferably 5 mm or more, and further preferably 10 mm or more, from the viewpoint of enhancing liquid absorption, shape retention of the non-woven fabric when wet, and function of suppressing the release of absorbed liquid. preferable.

(Measuring method of average fiber diameter)
Five small sample samples were randomly collected from the non-woven fabric to be measured, and 20 to 60 pieces were placed in the field of view using a scanning electron microscope (SEM) (for example, JCM-6000PLUS (trade name) manufactured by JEOL Ltd.). An image is taken in which the observation magnification is enlarged to, for example, 1000 to 10000 times so that the fibers are reflected. The average fiber diameter can be obtained by measuring the fiber diameter so as to count each fiber in the field of view once for each of the above photographs and rounding off the first decimal place of the average value.
(Method of measuring fiber length)
The non-woven fabric to be measured can be traced in the fiber length direction using, for example, SEM, and the fiber length of each fiber can be obtained.

The non-woven fabric for absorbent articles of the present invention may contain short fibers having a fiber length of less than 1 mm as long as it has at least one layer of the above-mentioned long fibers and can exert the above-mentioned action. In this case, the mass ratio of the short fibers in the non-woven fabric for absorbent articles is preferably 10% or less, more preferably 5% or less. Further, a highly absorbent polymer material may be arranged as long as it does not hinder the liquid absorbability, the liquid return reduction property and the thinning by the long fiber layer. In this case, the mass ratio of the highly absorbent polymer material in the non-woven fabric for absorbent articles is preferably 10% or less, more preferably 5% or less. However, it is particularly preferable that the non-woven fabric for absorbent articles of the present invention does not contain short fibers or a highly absorbent polymer material and consists only of the above-mentioned long fiber layer.

The basis weight of the absorbent article for nonwoven fabric of the present invention, from the viewpoint of realizing a thinner while maintaining a high absorbent liquid absorbent is preferably 300 g / m ² or less, more preferably 200 g / m ^2, 100 g / M ² or less is more preferable. Further, the basis weight of the non-woven fabric for absorbent articles of the present invention is preferably 4 g / m ² or more, more preferably 7 g / m ² or more, and 10 g / m ² or more from the viewpoint of enhancing the liquid absorbency and the liquid return reducing property of the absorber. More than m ^{2 is} more preferable.

(Method of measuring the basis weight of the non-woven fabric for absorbent articles of the present invention)
The weight and area of the non-woven fabric to be measured can be obtained, and the basis weight of the non-woven fabric for absorbent articles can be measured by dividing the weight by the area.

As described above, the absorber according to the present invention contains the non-woven fabric for absorbent articles of the present invention, maintains high absorbency, and realizes both thinning and reduction of liquid return. In the absorber according to the present invention, at least one non-woven fabric for absorbent articles of the present invention is contained, and two or more may be contained. Further, the absorber according to the present invention may be formed by combining the non-woven fabric for an absorbent article of the present invention with other members as long as the action and effect of the present invention are not impaired. However, from the viewpoint of maintaining high absorbency and achieving both thinning and reduction of liquid return, the absorber according to the present invention is preferably composed of only the non-woven fabric for absorbent articles of the present invention.

The absorber containing the non-woven fabric for absorbent articles of the present invention preferably comprises only a fiber material. That is, it is preferable that the highly absorbent polymer material is not contained. As a result, the absorber according to the present invention can avoid the occurrence of gel blocking due to the highly absorbent polymer material, and can improve the absorption rate as well as the liquid return reducing property in spite of the thinning.
The fiber material contained in the absorber according to the present invention is preferably composed only of synthetic fibers. That is, it is preferable that the non-woven fabric for absorbent articles of the present invention is composed only of synthetic fibers. As a result, the shape-retaining property of the absorber when wet is further enhanced, and the liquid return reducing property is further enhanced.

Further, the long fibers contained in the non-woven fabric for absorbent articles of the present invention are preferably hydrophilic polyolefin fibers. As a result, both the shape-retaining property of the absorber when wet and the economic efficiency of the absorbent article can be achieved. Further, it is preferable that the long fibers have a hydrophilizing agent inside the fibers. By containing the hydrophilic agent in the fiber, the hydrophilicity of the fiber can be easily maintained even if the absorber repeatedly absorbs the liquid. As a result, the absorption performance (absorption rate and absorption capacity) of the absorber and the liquid return reducing property can be easily maintained. The addition (internal addition) of such a hydrophilizing agent to the inside of the fiber can be carried out by various methods used in the non-woven fabric. For example, a spinning direct-coupled manufacturing method using a molten resin (for example, a melt blown method) can be mentioned. Specifically, a hydrophilic agent is added to the molten resin and mixed, and the molten resin is discharged from a nozzle of an ultrafine spinneret. A jet stream of high-temperature gas or the like is blown onto the discharged molten resin to form ultrafine cotton-like fibers, which are deposited and cooled to form a non-woven fabric.

As the synthetic fiber and the hydrophilic agent, various ones usually used in an absorbent article can be used without particular limitation.

(Method of confirming the hydrophilizing agent contained in the long fibers)
By analyzing the change in hydrophilicity performance with time and the cross section of the long fiber (cross section in the fiber radial direction) by the surface analysis method, the hydrophilic agent contained in the long fiber can be confirmed. For example, it can be confirmed that the hydrophilic performance of the layer of long fibers whose surface hydrophilicity is once lost by washing with a solvent or the like and washed away, or that the hydrophilic performance is improved with time, or the cross section of the long fibers (fiber diameter). The cross section in the direction) can be confirmed by analyzing the time-of-flight type secondary ion mass spectrometry or the like and detecting the hydrophilic agent inside the fiber.

The absorber according to the present invention may contain the non-woven fabric for absorbent articles of the present invention in either a single layer or a plurality of layers. By forming a laminated structure of a plurality of layers, ultrathin planar voids are formed between the layers, and the planar voids can enhance the liquid absorption performance in conjunction with the above-mentioned dense three-dimensional void structure in the layer. ,preferable. Specifically, the dense three-dimensional void structures in each layer are connected by ultrathin planar voids between layers, and are linked in the plane direction and the thickness direction, and a dense and intricate three-dimensional liquid flow path or storage. A gap is formed. As a result, in the three-dimensional void structure in the layer, the liquid is stored while being diffused in the direction of the fiber length of the long fibers in a plurality of streaky liquid flow paths (storage gaps) that cooperate with each other, and the stored liquid is stored between the layers. The planar voids are received by the surface and further delivered to the three-dimensional void structure in the next layer. That is, the liquid absorption power between the layers and the absorption power of the dense (for example, nanometer order) streaky liquid flow path (storage gap) of each layer are linked in the thickness direction of the absorber to develop a strong liquid drawing power. However, the absorption performance (absorption rate and absorption capacity) of the absorber and the liquid return reducing property can be further improved.
Even when the absorber according to the present invention contains the non-woven fabric for absorbent articles of the present invention in either a single layer or a plurality of layers, the orientation direction along the fiber length of the long fibers is the longitudinal direction of the absorber. Is preferable. As a result, the liquid can be efficiently absorbed by the entire absorber, and the preventive property of lateral leakage of the excrement liquid in the absorbent article incorporating the absorber can be enhanced. In the form of a multi-layer laminated structure, a plurality of non-woven fabrics for absorbent articles of the present invention may be laminated, or the non-woven fabric for absorbent articles of the present invention may be folded and laminated.
In addition, it is preferable that the thickest portion of the folding structure is arranged in the portion of the absorber corresponding to the receiving region (excretion point) that directly receives the excretion of the liquid in the absorbent article. As a result, it is possible to realize the diffusion of the liquid along the fiber length of the long fibers and the liquid absorption in the thickness direction over many layers in the liquid receiving region. As a result, the absorber according to the present invention can quickly absorb the liquid with a high absorption capacity, suppress the leakage of the liquid, and further enhance the liquid return reducing property due to pressurization or the like.

As described above, the liquid receiving region (excretion point) is a region that directly receives the excretory liquid in the absorbent article, and is appropriately set according to the type of the absorbent article and the like. For example, when the absorbent article is a sanitary napkin or panty liner for daytime, the liquid receiving region is an intermediate portion divided into three equal parts in the longitudinal direction, and the length of the intermediate portion in the width direction is 2 mag. The area is within 2.5 cm in the left-right width direction from the dividing line. If the absorbent article is a sanitary napkin with a wide rear flap that covers the buttocks, such as for night use, it is the second part divided into four equal parts in the longitudinal direction, and the length in the width direction of the part is second magnitude. The area within 2.5 cm in the left-right width direction from the dividing line is the liquid receiving area. When the absorbent article is a diaper, from the line that divides the length in the width direction into two equal parts, from the line that divides the length in the longitudinal direction into two equal parts within 3.5 cm in the left and right width directions. It is an area within 8 cm in the anterior direction. If the absorbent article is a urine absorbing pad or an incontinence pad, it is set in the same way as a diaper.

The basis weight of the absorber containing the non-woven fabric for absorbent articles of the present invention is preferably 10 g / m ² or more, more preferably 50 g / m ² or more, and 100 g / m ² or more from the viewpoint of enhancing liquid absorption and liquid return reduction. More than m ^{2 is} more preferable. From the viewpoint of thinning, the basis weight of the absorber is preferably 500 g / m ² or less, more preferably 400 g / m ² or less, and even more preferably 300 g / m ² or less.
Further, the thickness of the absorbent body including the non-woven fabric for absorbent articles of the present invention is preferably thinner from the viewpoint of thinning, but preferably has a certain thickness or more from the viewpoint of wearing comfort. Specifically, the preferable thickness of the absorber may change depending on the type of the absorbent article.
For example, when the absorbent article is a panty liner, the thickness of the absorber is preferably 0.6 mm or less, more preferably 0.5 mm or less, still more preferably 0.4 mm or less from the viewpoint of thinning. When the absorbent article is a panty liner, the thickness of the absorber is preferably 0.05 mm or more, more preferably 0.1 mm or more, still more preferably 0.15 mm or more, from the viewpoint of a sense of security in wearing.
For example, when the absorbent article is a sanitary napkin, the thickness of the absorber is preferably 10 mm or less, more preferably 7 mm or less, still more preferably 4 mm or less, from the viewpoint of thinning. When the absorbent article is a sanitary napkin, the thickness of the absorber is preferably 0.5 mm or more, more preferably 1 mm or more, still more preferably 1.5 mm or more, from the viewpoint of comfort in wearing.
For example, when the absorbent article is a diaper for children, the thickness of the absorber is preferably 10 mm or less, more preferably 5 mm or less, still more preferably 3 mm or less, from the viewpoint of thinning. When the absorbent article is a diaper for children, the thickness of the absorber is preferably 0.5 mm or more, more preferably 1 mm or more, still more preferably 1.5 mm or more, from the viewpoint of comfort in wearing.
For example, when the absorbent article is an adult diaper, the thickness of the absorber is preferably 12 mm or less, more preferably 6 mm or less, still more preferably 3 mm or less, from the viewpoint of thinning. When the absorbent article is an adult diaper, the thickness of the absorber is preferably 0.5 mm or more, more preferably 1 mm or more, still more preferably 1.5 mm or more, from the viewpoint of comfort in wearing.

The absorber containing the non-woven fabric for absorbent articles of the present invention can be applied to various absorbent articles that absorb and retain excrement. Specific examples of the absorbent article include sanitary napkins, panty liners, diapers, incontinence pads, urine absorbing pads and the like. The excretory fluid is not limited to urine, but various substances such as menstrual blood can be targeted. In particular, in sanitary napkins, the effect of improving the absorption rate is remarkable as well as the thinning of the absorber and the reduction of liquid return. Further, in the panty liner, the absorption body is made thinner while maintaining a high absorption rate, and the effect of reducing liquid return becomes remarkable.

The absorbent article typically comprises a front sheet, a back sheet and a liquid-retaining absorber interspersed between the sheets. Further, a liquid diffusible second sheet may be arranged between the surface sheet and the absorber.
When the non-woven fabric for an absorbent article of the present invention is applied to an absorbent body, as the front sheet, the back sheet and the second sheet, materials usually used in the art can be used without particular limitation. For example, examples of the surface sheet include a hydrophilic air-through non-woven fabric. As the back sheet, a film made of a thermoplastic resin or a liquid-impermeable or water-repellent sheet such as a laminate of the film and a non-woven fabric can be used. The back sheet may have water vapor permeability. Examples of the second sheet include hydrophilic non-woven fabrics and crepe papers. The absorbent article may further include various members according to the specific use of the absorbent article.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not construed as being limited thereto.

(Example 1)
A non-woven fabric sample 1 for an absorbent article composed of a layer of long fibers shown in Table 1 was prepared by a melt blown method using a polypropylene resin mixed with a hydrophilizing agent. The non-woven fabric sample 1 for absorbent articles is cut into a size of 100 mm in the longitudinal direction × 65 mm in the width direction, folded toward the front side at 15 mm from one end in the width direction, and subsequently 20 mm from the opposite end in the width direction. By the way, by folding it toward the front side in the same way, the non-woven fabric for absorbent articles has an apparent size of 100 mm in the longitudinal direction x 30 mm in the width direction, which is double-folded (triple for a part of 100 mm in the longitudinal direction x 5 mm in the width direction). Sample 1 is prepared, two of them are prepared and laminated (separately laminated so that the triple-folded portions of the respective non-woven fabric samples 1 for absorbent articles do not overlap), and the absorber sample 1 shown in Table 1 is laminated. Was produced. The absorber sample 1 thus produced had a size of 100 mm in the longitudinal direction × 30 mm in the width direction and a basis weight of 40 g / m ² (60 g / m ² for a part of 100 mm in the longitudinal direction × 10 mm in the width direction).
The surface sheet and the second sheet used in the panty liner manufactured by Kao Corporation (trade name: Laurier Clean Style Unscented 2017) are laminated on the above-mentioned absorber sample 1, and the absorbent article sample 1 of Example 1 is laminated. Was produced.

(Example 2)
Examples shown in Table 1 are the same as in Example 1 except that a non-woven fabric sample for an absorbent article is cut into a size of 100 mm × 60 mm in the longitudinal direction, two of them are prepared and the two are laminated without folding. The absorber sample 2 and the absorbent article sample 2 of 2 were prepared.

(Example 3)
Similar to Example 1, a double-folded (triple for a part of 100 mm in the longitudinal direction × 5 mm in the width direction) non-woven fabric sample 1 for an absorbent article was prepared, and only one of these was used as an absorber sample. Except for the above, the absorber sample 3 and the absorbent article sample 3 of Example 3 shown in Table 1 were prepared in the same manner as in Example 1.

(Example 4)
The absorber sample 4 and the absorbent article sample 4 of Example 4 shown in Table 1 were prepared in the same manner as in Example 3 except that the second sheet was not arranged.

(Comparative Example 1)
An absorbent article sample C1 of Comparative Example 1 was prepared by laminating a surface sheet, a second sheet and an absorber used in a panty liner manufactured by Kao Corporation (trade name: Laurier Clean Style Unscented 2017). The absorbers used here are as shown in Table 1.

(Comparative Example 2)
A non-woven fabric sample C2 for an absorbent article composed of a layer of long fibers shown in Table 1 was prepared by a spunbond method using a polypropylene resin mixed with a hydrophilizing agent. The non-woven fabric sample C2 for absorbent articles is cut into a size of 100 mm in the longitudinal direction × 65 mm in the width direction, folded toward the front side at 15 mm from one end in the width direction, and subsequently 20 mm from the opposite end in the width direction. By the way, by folding it toward the front side in the same manner, a sample having an apparent size of 100 mm in the longitudinal direction × 30 mm in the width direction and double (triple for a part of 100 mm in the longitudinal direction × 5 mm in the width direction) is prepared. This was designated as the absorber sample C2 shown in Table 1.
For this absorber sample C2, the absorbent article sample C2 of Comparative Example 2 was prepared in the same manner as in Example 3.

(Test 1)
An acrylic plate (160 mm x 60 mm, 75 g) having a transmission hole with an inner diameter of 1 cm is placed on the surface sheet of each absorbent article sample, and two 140 g weights are evenly placed on the acrylic plate (160 mm × 60 mm, 75 g) so as to sandwich the transmission hole. ) Placed. Under such a load, 0.5 g of pseudo blood (horse defibered blood manufactured by Japan Biotest Research Institute Co., Ltd. adjusted to 8.0 cP) corresponding to menstrual blood was added to the dropper from the permeation hole of the acrylic plate. Pour in using. The horse defibered blood used was adjusted with a TVB10 viscometer manufactured by Toki Sangyo Co., Ltd. under the condition of 30 rpm. When left untreated, horse defibrous blood precipitates high-viscosity parts (erythrocytes, etc.) and low-viscosity parts (plasma) remain as supernatant. The mixing ratio of that part was adjusted to 8.0 cP.
After pouring in the pseudo blood and letting it stand for 1 minute, the acrylic plate was removed. Next, the filter paper No. cut into 80 mm × 60 mm was applied to the portion of each absorbent article sample into which the pseudo blood was charged. After stacking 2 and applying a load of 3 g / cm ² for 10 seconds, the mass (W2) of the filter paper was measured. The difference (W2-W1) between the measured mass of the filter paper (W2) and the previously measured mass of the filter paper (W1) before being stacked on each absorbent article sample was calculated and used as the liquid return amount.
Further, at the time of evaluation of the liquid return amount test described above, the time until the entire amount of 0.5 g was absorbed by each absorbent article sample was measured.

As shown in Table 1, in Examples 1 to 4, the amount of liquid return was suppressed as compared with Comparative Examples 1 and 2, and the liquid return could be sufficiently reduced. In particular, in Examples 1 and 2 in which the non-woven fabric was laminated, high liquid return prevention property was exhibited. Further, in Examples 1 to 3, the absorption time of the pseudo blood was short and the liquid absorption rate was excellent.
As described above, the absorber containing the non-woven fabric for the absorbent article of the present invention can reduce the liquid return even if the basis weight is low, and can achieve both the thinning of the absorber and the reduction of the liquid return in the absorbent article. You can see that.

(Example 5)
A non-woven fabric sample 5 for an absorbent article composed of a layer of long fibers shown in Table 2 was prepared by a melt blown method using a polypropylene resin mixed with a hydrophilizing agent. The absorbent sample 5 shown in Table 2 was prepared by laminating three non-woven fabric samples 5 for absorbent articles.
The surface sheet used in the sanitary napkin manufactured by Kao Corporation (trade name: Loriev Happy Bare Skin 22.5 cm, manufactured in 2017) is laminated on the above-mentioned absorber sample 5, and the absorbent article sample 5 of Example 5 is obtained. Made.

(Example 6)
Similar to Example 5, the non-woven fabric sample 6 for absorbent articles, the absorber sample 6 and the absorbent article sample shown in Table 2 are shown in Table 2 except that the number of laminated non-woven fabric samples for absorbent articles is four. 6 was prepared.

(Example 7)
Three non-woven fabric samples for absorbent articles used in Example 5 were laminated as the first non-woven fabric sample for absorbent articles 71, and the average fiber diameter was different from this, and the non-woven fabric sample for second absorbent articles shown in Table 2 was laminated. Absorbent sample 7 and absorbent article sample 7 of Example 7 shown in Table 2 were prepared in the same manner as in Example 5 except that 72 was prepared and laminated on the skin surface side of the three sheets.

(Comparative Example 3)
A surface sheet and an absorber used in a sanitary napkin manufactured by Kao Corporation (trade name: Loriev Happy Bare Skin 22.5 cm, manufactured in 2017) were laminated to prepare an absorbent article sample C3 of Comparative Example 3. The absorbers used here are as shown in Table 2.

(Comparative Example 4)
Table 5 in the same manner as in Example 5 except that four non-woven fabric samples C4 for absorbent articles similar to the non-woven fabric sample 72 for second absorbent articles used in Example 7 were stacked to form an absorber sample C4. Nonwoven fabric sample C4 for absorbent article, absorber sample C4 and absorbent article sample C4 of Comparative Example 4 shown in 2 were prepared.

(Comparative Example 5)
A non-woven fabric sample C5 for absorbent articles shown in Table 2 was prepared by a spunbonding method using a polypropylene resin mixed with a hydrophilizing agent. The absorbent sample C5 shown in Table 2 was prepared using the non-woven fabric sample C5 for absorbent articles.
The surface sheet used in the sanitary napkin manufactured by Kao Corporation (trade name: Loriev Happy Bare Skin 22.5 cm, manufactured in 2017) is laminated on the above-mentioned absorber sample C5, and the absorbent article sample C5 of Comparative Example 5 is laminated. Made.

(Test 2)
(1) An acrylic plate (200 mm × 100 mm, 210 g) having a transmission hole with an inner diameter of 1 cm was placed on the surface sheet of each absorbent article sample. Under such a load, 3 g of the pseudo blood used in the above (Test 1) was injected at once from the through hole of the acrylic plate, and the absorption time was measured.
(2) After pouring the pseudo blood and letting it stand for 45 seconds, the acrylic plate was removed. Next, 1 minute after the injection, a tissue folded to 95 mm × 56 mm and a weight (104 mm × 30 mm, 125 g) were placed on the portion of each absorbent article sample into which the simulated blood was injected, and placed for 5 seconds to obtain the mass of the tissue (104 mm × 30 mm, 125 g). W4) was measured. The difference (W4-W3) from the mass (W3) of the tissue before being stacked on each absorbent article sample, which was measured in advance, was calculated and used as the amount of liquid return.
(3) Inject 3 g of pseudo blood onto a napkin + plate 3 minutes and 6 minutes after the start of evaluation (injection of pseudo blood). Repeat the steps (1) and (2) above to add a total of 9 g of pseudo blood. Infused. The amount of liquid return and the absorption time at the time of injecting 3 g, 6 g, and 9 g were measured.

As shown in Table 2, in Examples 5 to 7, the amount of liquid return was significantly smaller at the time of injection of 3 g, 6 g, or 9 g of pseudo blood as compared with Comparative Examples 4 and 5, and liquid return was performed. It was able to be reduced sufficiently. Further, in Examples 5 to 7, the absorption time of pseudo blood was equal to or less than that of Comparative Examples 3 to 5.
As described above, the absorber containing the non-woven fabric for the absorbent article of the present invention can reduce the liquid return even if the basis weight is low, and can achieve both the thinning of the absorber and the reduction of the liquid return in the absorbent article. You can see that. Further, it can be seen that the absorption time and the liquid return property at the time of repeated absorption can be remarkably improved with respect to the absorber containing the highly absorbent polymer material (SAP).

Claims (9)

A non-woven fabric for absorbent articles that is hydrophilic and contains a layer of long fibers having an average fiber diameter of 1 μm or less. An absorber containing the non-woven fabric for absorbent articles according to claim 1. The absorber according to claim 2, wherein the absorber is made of only a fiber material containing the long fibers. The absorber according to claim 3, wherein the fiber material is a synthetic fiber. The absorber according to any one of claims 1 to 4, wherein the long fiber is a polyolefin-based fiber obtained by hydrophilization. The absorber according to any one of claims 1 to 5, wherein the long fiber has a hydrophilizing agent inside the fiber. An absorbent article comprising a surface sheet and the absorber according to any one of claims 2 to 6. An absorbent article having an absorber according to any one of claims 2 to 6, which is interposed between the front surface sheet, the back surface sheet, and the back surface sheet. The absorbent article according to claim 7 or 8, which has a second sheet between the surface sheet and the absorber.