JP5916292B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article comprising a web of tow.

  The use of tow for absorbent articles has been studied. Since the tow has the same fiber direction, it is expected that the absorbed liquid can be quickly diffused when it is used in an absorbent article. However, the tow is bulky and has many interstices between fibers, and can quickly diffuse the absorbed liquid, but after absorbing the liquid, it crushes and its thickness decreases, resulting in a decrease in liquid permeability. It has a drawback that is easy to do. Therefore, various studies have been conducted to improve the defect.

  For example, Patent Document 1 discloses an absorbent body including a fiber assembly made of tows composed of fibers, in which the contact portion between fibers is bonded or melted by a line or a point by applying a binder. An absorber is described which is characterized in that it is worn. Patent Document 1 aims to maintain the liquid permeability by adhering tow fibers with a binder to retain the shape even after absorbing the liquid.

  Patent Document 2 discloses an absorbent article including an absorbent body including a web of hydrophilic long fibers, wherein the web has a network structure in which the intersections of the long fibers are combined. An absorbent article in which a superabsorbent polymer is embedded and supported in the network structure, and the bonded state of the long fibers is weakened or released by the web becoming wet is described. Has been. The absorbent article described in Patent Document 2 is designed such that the intersection is formed by a water-soluble adhesive, and when the liquid is absorbed, the water-soluble adhesive dissolves and the intersection disappears.

JP 2006-14887 A JP 2006-262916 A

However, in the absorbent body described in Patent Document 1, since the intersection of the fibers is formed by adhesion, when the liquid is absorbed, the absorbent body cannot be deformed and the swelling of the superabsorbent polymer is inhibited. There is a case. Further, in the absorbent article described in Patent Document 2, since the intersection of fibers is formed by the water-soluble adhesive, when the liquid is absorbed, the water-soluble adhesive dissolves and the intersection disappears. The body is crushed and the liquid permeability tends to decrease. In addition, the dissolved water-soluble adhesive may cover the surface of the superabsorbent polymer and inhibit the superabsorbent polymer from absorbing the liquid, and migrate to the skin contact surface of the absorbent article, May adhere to user's skin.
Accordingly, an object of the present invention is to provide an absorbent article including a web made of a tow which is excellent in liquid diffusibility and hardly deforms after absorbing the liquid and maintains the liquid diffusibility.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a liquid-permeable top sheet, a liquid-impermeable back sheet, the liquid-permeable top sheet, and a liquid-impermeable back sheet An absorbent article, wherein the absorbent article comprises a web of tows, the web of tows comprising a plurality of ridges along the toe fiber orientation direction, and An absorbent article having a plurality of groove portions and a ridge groove surface, wherein the web made of the tow has a plurality of entanglement points formed by entanglement of the fibers of the tow. The present inventors have found that the above problems can be solved and have completed the present invention.

Specifically, the present invention relates to the following aspects.
[Aspect 1]
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 article comprises a web of tow;
The web comprising the tow has a ridge groove surface including a plurality of ridge portions and a plurality of groove portions along the orientation direction of the fibers of the tow,
The tow web has a plurality of entanglement points formed by entanglement of the tow fibers.
The said absorbent article characterized by the above-mentioned.

[Aspect 2]
The absorbent article according to aspect 1, wherein the tow web is arranged so that the orientation direction of the fibers of the tow coincides with the longitudinal direction of the absorbent article.
[Aspect 3]
The absorbent article according to aspect 1 or 2, wherein in the web made of the tow, the amount of fibers in the heel portion is larger than the amount of fibers in the groove portion.

[Aspect 4]
The absorbent article according to any one of aspects 1 to 3, wherein the absorbent body includes a web made of the tow.
[Aspect 5]
The absorbent article according to aspect 4, wherein the absorbent body further includes a superabsorbent polymer, and the superabsorbent polymer is present more in the groove portion than in the heel portion of the web made of the tow.

[Aspect 6]
A web comprising the tow is a top sheet, a second sheet disposed between the top sheet and the absorber, and / or a third disposed between the absorber and the back sheet. The absorbent article according to any one of aspects 1 to 3, which is a sheet.
[Aspect 7]
The absorbent article according to any one of aspects 1 to 6, wherein the liquid diffusion length of the web made of the tow is 40 mm or more in the orientation direction of the fibers of the tow.

[Aspect 8]
The absorbent article according to any one of aspects 1 to 7, wherein the towed web has a thickness retention of 60% or more.
[Aspect 9]
The absorbent article according to any one of aspects 1 to 8, wherein the web comprising the tow has a thickness retention of 60% or more when containing water.

[Aspect 10]
The absorbent article according to any one of aspects 1 to 9, wherein the web comprising the tow is formed by spraying a fluid on the tow along the orientation direction of the fibers of the tow.
[Aspect 11]
The absorbent article according to aspect 10, wherein the tow web has a breaking strength of 1.5 times or more with respect to a direction orthogonal to the fiber orientation direction as compared to the tow before spraying the fluid.

  The web made of tow contained in the absorbent article of the present invention has excellent liquid diffusibility, and is difficult to deform after absorbing the liquid, and retains the liquid diffusibility.

FIG. 1 is a perspective view of a web made of tows according to the present invention. FIG. 2 is a diagram showing an example of the absorbent article of the present invention. FIG. 3 is a cross-sectional view of one embodiment of the absorbent article of the present invention. FIG. 4 is a cross-sectional view of one embodiment of the absorbent article of the present invention. FIG. 5 is an enlarged view of a groove surface of a web made of tow. FIG. 6 is a cross-sectional view of one embodiment of the absorbent article of the present invention. FIG. 7 is a cross-sectional view of one embodiment of the absorbent article of the present invention. FIG. 8 is a diagram showing an example of a method for forming a web made of tow. FIG. 9 is a photograph of the web made of tow produced in Example 1 taken with the ridges in front. FIG. 10 is a photograph of the toe web produced in Example 1 taken from the cross-sectional direction.

The absorbent article of the present invention will be described in detail below.
FIG. 1 is a perspective view of a web made of tows according to the present invention. The web 1 made of tow shown in FIG. 1 has a ridge groove surface 6 including a plurality of ridge portions 2 and a plurality of groove portions 3 along the orientation direction O of the fibers of the tow. The web 1 made of tow shown in FIG. 1 has a plurality of entanglement points 5 formed by entanglement of tow fibers 4 with each other.

  In the absorbent article of the present invention, the orientation direction of the tow fibers is not particularly limited. For example, when the orientation direction of the tow fibers coincides with the longitudinal direction of the absorbent article, the tow fibers are composed of, for example, tow. When the web is included in the absorbent body, the superabsorbent polymer is difficult to move, the distribution of the superabsorbent polymer is less likely to be biased, and the user is less likely to feel discomfort when the liquid is absorbed. Moreover, the absorbed liquid can be quickly moved in the longitudinal direction of the absorbent article. Further, since the liquid easily penetrates the groove portion, the absorption speed can be increased, leakage can be reduced, and the groove portion is a starting point of bending, so that the absorbent body is flexible and easily fits the body.

  In the absorbent article of the present invention, the liquid absorbed by the tow web diffuses rapidly through the voids between the fibers of the substantially parallel tow by capillary action. As a result, the absorbed liquid can be received in a wide range of the absorber, so that it is difficult to leak, the thickness of the absorber can be reduced, and the amount of superabsorbent polymer can be reduced.

Further, in the web made of tow shown in FIG. 1, the amount of fibers in the heel part 2 is larger than the amount of fibers in the groove part 3.
In the present specification, the “amount of fiber” related to the heel portion and the groove portion means the mass of the fiber existing in the thickness direction based on the unit area in the plane direction of the web made of tow.
In the absorbent article of the present invention, the amount of the fibers in the heel portion is larger than the amount of the fibers in the groove portion, so that the compression rate is excellent, and even when body pressure is applied, the absorption rate is unlikely to decrease, Leakage during long-time use can be reduced.

  In the present specification, the “entanglement point” formed by the entanglement of tow fibers is that at least two tow fibers are in contact with each other, and the direction of at least one tow fiber is changed at those contact points. It means the part that is.

The web comprising the tow according to the present invention has a plurality of the entanglement points, but the entanglement points are formed by entanglement of fibers and are not fixed by an adhesive or the like. Therefore, when the web made of tow is included in the absorbent body containing the superabsorbent polymer, the web made of tow can follow the swelling of the superabsorbent polymer, but the absorbent body is deformed. Can also be suppressed. Further, even when the user moves violently, the shape of the absorbent article can be maintained to some extent. Furthermore, since no water-soluble adhesive is used to form the entanglement point, the absorption inhibition of the superabsorbent polymer is unlikely to occur.
In the absorbent article of the present invention, the web of tow can be free of adhesive.

  Next, an embodiment in which the absorbent article of the present invention includes a web made of tow will be described with a specific example. As a typical example of an absorbent article, FIG. 2 shows an open-type disposable diaper. The absorbent article 7 shown in FIG. 2 includes a liquid-permeable top sheet 8, a liquid-impermeable back sheet (not shown), a liquid-permeable top sheet 8 and a liquid-impermeable back sheet. And a leak barrier 9 and a tape fastener 10 are further included.

Examples of webs made of tows according to the present invention include FIGS. 3, 4, 6 and 7. FIG.
FIG. 3 is a cross-sectional view of one embodiment of the absorbent article of the present invention, and corresponds to the XX cross-section of FIG. The absorbent article 7 shown in FIG. 3 includes a liquid-permeable top sheet 8, a liquid-impermeable back sheet 12, and absorption between the liquid-permeable top sheet 8 and the liquid-impermeable back sheet 12. And the absorbent body 11 includes a web 1 made of tow. In the absorbent article 7 shown in FIG. 3, the web 1 made of tow has a ridge groove surface 6 including a plurality of ridge portions 2 and a plurality of groove portions 3 along the orientation direction of the fibers of the tow, And it has the entanglement point formed when the fibers of tow are entangled. Further, in the absorbent article 7 shown in FIG. 3, the web 1 made of tow is arranged so that the orientation direction of the fibers of the tow coincides with the longitudinal direction of the absorbent article 7.

  FIG. 4 is a cross-sectional view of one embodiment of the absorbent article of the present invention, and corresponds to the XX cross section of FIG. The absorbent article 7 shown in FIG. 4 includes a liquid-permeable top sheet 8, a liquid-impermeable back sheet 12, and absorption between the liquid-permeable top sheet 8 and the liquid-impermeable back sheet 12. The body 11 is included, and the absorbent body 11 includes a laminate in which two layers of webs 1 made of tow are laminated. In the absorbent article 7 shown in FIG. 4, the web 1 made of tow has a plurality of ridges 2 and a plurality of grooves 3 along the orientation direction of the fibers of the tow. These fibers have entanglement points formed by entanglement of the fibers. Moreover, in the absorbent article 7 shown in FIG. 4, the web 1 made of tow is arranged so that the orientation direction of the fibers of the tow coincides with the longitudinal direction of the absorbent article 7 in both layers.

In the absorbent article of the present invention, the absorbent body may further include a superabsorbent polymer. However, when the absorbent body includes a web made of tow, the superabsorbent polymer is a ridge of the web made of tow. It is preferable that there are more in the groove portion than in the portion. Due to the presence of the superabsorbent polymer in the groove, the superabsorbent polymer is less likely to move, the distribution of the superabsorbent polymer is less likely to be biased, and the absorbent article is relatively uniform when absorbing liquid. Because it is easy to swell, it is difficult for the user to feel uncomfortable.
In addition, in the web made of tow, in principle, the ends in the orientation direction of the tow fibers are coincident with the ends of the fibers, so that a superabsorbent polymer is dispersed on the web made of tows. In addition, it is difficult to prevent the superabsorbent polymer from entering the groove, and the high-grade polymer tends to gather in the groove.

  Further, as shown in FIG. 4, in the embodiment in which the web made of the tow is laminated in the absorbent body, the absolute amount of the groove portion that is easy to hold the superabsorbent polymer is increased, and a larger amount of the absorbent is obtained. This is preferable because it can contain a polymer. From this point of view, in the absorbent article of the present invention, when the absorbent body includes a web made of tow, the tow web is preferably laminated in two or more layers, and three or more layers are laminated. More preferably.

  FIG. 5 is an enlarged view of a groove surface of a web made of tow. In the web 1 made of tow shown in FIG. 5, the amount of the superabsorbent polymer 13 present in the heel part 2 is smaller than the amount of the superabsorbent polymer 13 present in the groove part 3, and expanded after absorbing the liquid. The superabsorbent polymer 13 is less likely to inhibit further liquid permeation. Although not shown in FIG. 5, a superabsorbent polymer 13 may be present inside the web 1 made of tow.

FIGS. 3 and 4 show an embodiment in which the absorbent body includes a web composed of one or two layers of tow and an optional superabsorbent polymer. However, in the absorbent article of the present invention, these are shown. The absorbent article of the present invention includes, for example, an embodiment in which the absorbent body includes a web composed of three or more layers of tows, an embodiment in which the absorbent body includes a web composed of tri-folded tows, and the like. include.
When the absorbent body contains a superabsorbent polymer, the web made of tow and the superabsorbent polymer can be covered with a core wrap.

  3 and 4, the web made of tow is arranged so that the orientation direction of the fibers of the tow coincides with the longitudinal direction of the absorbent article. However, in the absorbent article of the present invention, The fiber orientation of the absorbent article may not coincide with the longitudinal direction of the absorbent article. For example, the fiber orientation direction of the tow may be arranged so as to coincide with the direction orthogonal to the longitudinal direction of the absorbent article. . In addition, as shown in FIG. 4, when the absorbent body includes a web composed of two layers of tows, one layer is disposed so that the orientation direction of the fibers of the tow coincides with the longitudinal direction of the absorbent article. Then, the remaining one layer can be arranged so that the orientation direction of the tow fibers and the direction perpendicular to the longitudinal direction of the absorbent article coincide. In the absorbent article of the present invention, the web made of tow can quickly diffuse the liquid absorbed in the orientation direction of the tow fibers, so the direction in which the absorbed liquid is desired to diffuse and the orientation direction of the tow fibers. Should be matched.

The absorbent body is, for example, a web of tow placed on a tissue, on which a superabsorbent polymer is spread, for example about 80 g / m ² , and then a web of tow and a superabsorbent Laminate a polymer (about 80 g / m ² ), then a web of tow and a superabsorbent polymer (about 80 g / m ² ), a tissue on it, and then press It is formed by compression with a machine, for example, compression for 5 seconds at a pressure of 35 kg / cm ² .

When the web composed of the tow is included in the absorbent body, the basis weight thereof varies depending on the number of layers, the specific application, etc., for example, the basis weight of about 10 to about 1000 g / m ² , about 100 etc. can have a basis weight of about 500 g / m ^2. Further, when the web made of the tow is included in the absorbent body, the groove surface may face either the user side or the underwear side, but from the viewpoint of holding the superabsorbent polymer, the liquid is made from fiber. From the standpoint that the absorbed liquid can be quickly absorbed by the large amount of the groin and then the absorbed liquid can be transferred to the orientation direction of the tow fibers and the groove of the highly absorbent polymer, the grooving surface faces the user side. It is preferable.
By including the tow web in the absorbent body, the liquid absorbed by the absorbent body can be quickly diffused in a wide range, particularly in the orientation direction of the tow fibers, and absorbed without causing leakage.

  FIG. 6 is a cross-sectional view of one embodiment of the absorbent article of the present invention, and corresponds to the XX cross-section of FIG. The absorbent article 7 shown in FIG. 6 includes a liquid-permeable top sheet 8, a liquid-impermeable back sheet 12, and absorption between the liquid-permeable top sheet 8 and the liquid-impermeable back sheet 12. The second sheet 14 is further formed between the liquid permeable top sheet 8 and the absorbent body 11, and the second sheet 14 is formed from the web 1 made of tow. In the absorbent article 7 shown in FIG. 6, the web 1 made of tow has a ridge groove surface 6 including a plurality of ridge portions 2 and a plurality of groove portions 3 along the orientation direction of the fibers of the tow, And it has a plurality of entanglement points formed by entanglement of tow fibers. Moreover, in the absorbent article 7 shown in FIG. 6, the web 1 made of tow is arranged so that the orientation direction of the fibers of the tow and the longitudinal direction of the absorbent article 7 coincide.

When the tow web is arranged as a second sheet present between the liquid permeable top sheet and the absorbent body, it preferably has a basis weight of about 10 to about 100 g / m ² , and and more preferably has a basis weight of about 20 to about 50 g / m ^2. In addition, when the web made of the tow is arranged as a second sheet, the groove surface may face either the user side or the underwear side, but the liquid present in the top sheet is made up of the amount of fibers. It is preferable that the ridge surface is directed to the user side from the viewpoint that it can be absorbed quickly by capillary action at a large number of ridges, and then the absorbed liquid can be transferred to the orientation direction of the tow fibers.

  By forming the second sheet from a web made of tow, before the absorbed liquid is transferred to the absorbent body, it is quickly diffused in a wide area, in particular, in the orientation direction of the tow fibers, without causing leakage. Can be absorbed by an absorber.

  FIG. 7 is a cross-sectional view of one embodiment of the absorbent article of the present invention, and corresponds to the XX cross-section of FIG. The absorbent article 7 shown in FIG. 7 includes a liquid-permeable top sheet 8, a liquid-impermeable back sheet 12, and absorption between the liquid-permeable top sheet 8 and the liquid-impermeable back sheet 12. A third sheet 15 is formed between the absorbent body 11 and the liquid-impermeable back sheet 12, and the third sheet 15 is formed from a web 1 made of tow.

In the absorbent article 7 shown in FIG. 7, the web 1 made of tow has a ridge groove surface 6 including a plurality of ridge portions 2 and a plurality of groove portions 3 along the orientation direction of the fibers of the tow, And it has the entanglement point formed when the fibers of tow are entangled. Further, in the absorbent article 7 shown in FIG. 7, the web 1 made of tow is arranged so that the orientation direction of the fibers of the tow coincides with the longitudinal direction of the absorbent article 7.
In the present specification, for the sake of convenience, the web made of tow disposed between the absorber and the liquid-impermeable back sheet may be referred to as a “third sheet” for the sake of convenience.

When the towed web is arranged as a third sheet present between the absorbent body and the liquid-impermeable backsheet, it preferably has a basis weight of about 10 to about 100 g / m ² , and More preferably, it has a basis weight of about 20 to about 50 g / m ² . In addition, when the web made of the tow is arranged as a third sheet, the ridge groove surface may face either the user side or the underwear side, but the absorbent body cannot be absorbed and reaches the third sheet. From the viewpoint that the absorbed liquid can be quickly absorbed by capillarity in the heel portion having a large amount of fibers, and then the liquid absorbed in the orientation direction of the tow fibers can be transferred and then returned to the absorber. The surface is preferably facing the user side.
By forming the third sheet from a web made of tow, the third sheet can be quickly diffused in a wide range, particularly in the orientation direction of tow fibers, and returned to the absorbent body without causing leakage.

  In FIG. 6 and FIG. 7, the tow web is arranged so that the orientation direction of the tow fibers coincides with the longitudinal direction of the absorbent article. In the absorbent article of the present invention, the tow fibers are arranged. May not be aligned with the longitudinal direction of the absorbent article. For example, the orientation direction of the tow fibers may be arranged so as to coincide with the direction orthogonal to the longitudinal direction of the absorbent article. In the absorbent article of the present invention, the web made of tow can quickly diffuse the liquid absorbed in the orientation direction of the tow fibers, so the direction in which the absorbed liquid is desired to diffuse and the orientation direction of the tow fibers. Should be matched.

  In the absorbent article of the present invention, the liquid-permeable top sheet may be formed of a web made of tow. The liquid-permeable top sheet may be a laminate in which a web made of tow is laminated on a nonwoven fabric or the like.

When the tow web is used as a liquid permeable topsheet, it preferably has a basis weight of about 10 to about 100 g / m ² and has a basis weight of about 20 to about 50 g / m ² . It is more preferable to have. Further, when the web made of the tow is used as a top sheet, the ridge groove surface may face either the user side or the underwear side. It is preferable that the groove surface is directed to the user side from the viewpoint of absorbing the phenomenon quickly and then allowing the absorbed liquid to move in the orientation direction of the tow fibers.
The topsheet contains a web of tow so that the absorbed liquid can be quickly diffused in a wide area, especially in the direction of fiber orientation of the tow, without causing leakage, before transferring it to the absorbent body. Can be absorbed by the body.

  The web comprising the tow according to the present invention preferably has a liquid diffusion length of about 40 mm or more, more preferably about 50 mm or more, and more preferably about 60 mm or more in the toe fiber orientation direction. More preferably, it has a liquid diffusion length. When the liquid diffusion length is about 40 mm or more, the absorbed liquid can be quickly diffused in the orientation direction of the tow fibers.

The liquid diffusion length can be measured as follows.
1. A sample having a size of 100 × 100 mm is placed on a wire mesh having, for example, φ: 0.5 mm and pitch: 3 mm.
2. The lower end of the dropping funnel containing 40 g of physiological saline is fixed at the center of the test and at a height of 10 mm from the sample, and the physiological saline is dropped on the sample in about 5 seconds.
3. After about 30 seconds, the liquid diffusion length (the fiber orientation direction and its orthogonal direction), which is the length of diffusion of the physiological saline, is measured.

Moreover, the initial mass of the sample and the mass after the test of the sample when measuring the liquid diffusion length are measured, and the water absorption is expressed by the following formula (1):
Water absorption (%) = 100 × (mass after test−initial mass) / initial mass (1)
Can be obtained from
In addition, a measurement is implemented at room temperature (25 degreeC), and employ | adopts the average value of the result of 10 tests.

  The tow web according to the present invention preferably has a thickness retention of about 60% or more, and more preferably has a thickness retention of about 70% or more. When the thickness retention is about 60% or more, even when body pressure is applied, there is a tendency that deformation is difficult.

The thickness retention rate can be measured as follows.
1. The sample is cut to a size of 100 × 100 mm and the initial thickness is measured under a pressure of 0.5 kPa.
2. A weight is placed on the sample so that the pressure becomes 34.3 kPa, the pressure is applied for 1 minute, the weight is removed, and after 10 seconds, the thickness after pressurization is measured under a pressure of 0.5 kPa.
3. The thickness retention is expressed by the following formula (2):
Thickness retention (%) = 100 × thickness after pressing / initial thickness (2)
Ask according to.
In addition, a measurement is implemented at room temperature (25 degreeC), and employ | adopts the average value of the result of 10 tests.
The thickness can be measured by THICKNESS GAUGE UF-60 manufactured by Daiei Scientific Instruments.

  The tow web according to the present invention preferably has a thickness retention of about 60% or more, more preferably about 70% or more, and more preferably about 80% or more when wet. More preferably, it has a thickness retention. By having a thickness retention of about 60% or more when containing water, it tends to be difficult to deform after absorbing the liquid.

The thickness retention rate when containing water can be measured as follows.
1. The sample is cut to a size of 100 × 100 mm and the initial thickness is measured under a pressure of 0.5 kPa.
2. 10 g of physiological saline is added to the whole sample, and a weight is immediately placed so that the pressure is 34.3 kPa. The pressure is applied for 1 minute, the weight is removed, and 10 seconds later, the pressure is applied under a pressure of 0.5 kPa. Measure thickness after pressing.
3. The thickness retention is expressed by the following formula (3):
Thickness retention (%) = 100 × thickness after pressing / initial thickness (3)
Ask according to.
In addition, a measurement is implemented at room temperature (25 degreeC), and employ | adopts the average value of the result of 10 tests.
The thickness can be measured by THICKNESS GAUGE UF-60 manufactured by Daiei Scientific Instruments.

  Further, the web made of the tow according to the present invention has a breaking strength of about 1.5 times or more in the direction orthogonal to the fiber orientation direction, compared to the raw material tow, which does not have a groove surface and an entanglement point. Preferably, it has a breaking strength of about 2.0 times or more, and more preferably has a breaking strength of about 2.5 times or more. The web made of the tow according to the present invention has a plurality of entanglement points where the fibers of the tow are entangled, but it is difficult to directly evaluate the number, density, etc. of the entanglement points. Therefore, the density of the entanglement points can be indirectly evaluated by measuring the breaking strength in the direction orthogonal to the fiber orientation direction. This is because when the fibers are not entangled, the breaking strength should theoretically be close to zero.

The breaking strength can be measured as follows.
1. The sample is cut to a size of 25 mm in the fiber orientation direction and 100 mm in a direction perpendicular to the fiber orientation direction.
2. Both ends in the direction orthogonal to the fiber orientation direction of the sample are fixed to a chuck of a jig, and 10 mm is fixed to a digital force gauge with a distance between chucks of 80 mm. As said digital force gauge, the product made by SHIMPO and FGC-0.2 are mentioned, for example.
3. The digital force is stretched at 5 mm / second in a direction perpendicular to the orientation direction of the tow fiber, and the breaking strength, which is the strength when the sample breaks, is measured.
In addition, a measurement is implemented at room temperature (25 degreeC), and employ | adopts the average value of the result of 10 tests.
In addition to the measurement of the breaking strength, the elongation at break, which is the elongation when the sample breaks, can be measured.

  The web made of tow according to the present invention can be formed from tow. Tow is also referred to as a fiber bundle, and in the present specification, it means a bundle of continuous filaments in which each filament is oriented in a certain direction. As the material for the continuous filament, a hydrophilic fiber is preferable. Examples of the fiber having hydrophilicity include fibers having hydrophilicity in nature and fibers having essentially hydrophilicity but imparted with hydrophilicity by being subjected to a hydrophilic treatment.

  Examples of the essentially hydrophilic fiber include nylon, acrylic, acetate, and rayon. Examples of the fibers imparted with hydrophilicity include various synthetic fibers, that is, single fibers such as polyethylene, polypropylene, and polyethylene terephthalate, and composite fibers containing two or more of these treated with a surfactant. In the present invention, fibers that retain bulkiness even when wet are preferred, and acetate is preferred from the standpoint that it is essentially hydrophilic and hardly retains the liquid. As the acetate, cellulose triacetate and cellulose diacetate are preferable.

The web comprising the tow according to the present invention can be formed by spraying a fluid on the tow. By spraying a fluid on the tow, the tow fibers receive kinetic energy from the ejected fluid and entangle with other fibers to form an entanglement point. In addition, in the surface where the fluid collides (hereinafter referred to as the fluid collision surface), the ejected fluid collides and then rebounds, so that it is orthogonal to the conveying direction (hereinafter referred to as “orthogonal direction”). And a groove surface having a plurality of flange portions and a plurality of groove portions is formed.
In the absorbent article of the present invention, the conveying direction at the time of manufacture coincides with the orientation direction of the tow fibers and the directions of the plurality of ridges and grooves.

  FIG. 8 is a diagram showing an example of a method for forming a web made of tow. The tow 16 having a certain basis weight is placed on the support 17 so that the fiber orientation direction of the tow 16 coincides with the conveyance direction MD, that is, the axial direction of the fiber of the tow 16 coincides with the conveyance direction MD. The fluid ejected from the fluid nozzle 18 is sprayed on the tow 16. A suction part (not shown) for receiving fluid is provided under the fluid nozzle 18 with the support 17 interposed therebetween. The fluid ejected from the fluid nozzle 18 is sprayed on the tow 16 which is placed on the support 17 and carried, and the web 1 made of the tow having a specific groove structure and an entanglement point is formed. The sprayed fluid is discharged from a suction part (not shown).

  The basis weight of the tow for forming the web made of tow is substantially the same as the basis weight of the web made of tow described above. This is because the tow web and the tow size before the fluid is sprayed are substantially the same.

  In FIG. 8, a staggered punching plate is shown as the support body 17, but as the punching plate, for example, a round hole type, for example, a round hole 60 ° zigzag type, a round hole square zigzag, and a round hole series Examples of the punching plate include a mold, a square hole type, a round dove type, a cloud type, and a cloud staggered type.

  In addition, on the surface opposite to the fluid collision surface (hereinafter referred to as a non-fluid collision surface), a part of the fiber moves along the flow of the fluid. When a support having protrusions and depressions having a predetermined shape and arrangement is disposed, an uneven surface having protrusions and recesses is formed on the opposite side of the groove surface. You can also.

  Examples of the support having the protrusions and the depressions include (i) protrusions and depressions that are parallel to the conveying direction, and are alternately arranged in the orthogonal direction. (Ii) Projections and depressions having an inclination with respect to the conveying direction, and having projections and depressions alternately arranged in a direction perpendicular to the direction of the inclination A body, (iii) a projecting portion and / or a hollow portion having a predetermined shape (for example, a cubic shape, a columnar shape, a hemispherical shape, etc.), and a predetermined array (for example, a heart shape, a star shape, etc.) ) And the like having a projecting portion and a recessed portion arranged in the above.

  Examples of the fluid include air, for example, heated air, water vapor, for example, saturated water vapor and superheated water vapor, or water, for example, hot water. Considering that the subsequent drying step is unnecessary or less, heated fluid, saturated steam and superheated steam are preferable as the fluid.

  The fluid can be sprayed onto the tow from a fixed fluid nozzle or from a fluid nozzle that reciprocates in an orthogonal direction. In addition, the fluid can be sprayed from the fluid nozzle to the tow continuously or intermittently in order to adjust the entanglement point of the web made of tow and the shapes of the ridge and groove. Moreover, these can also be combined.

  In the web composed of the tow, the groove is formed at a location where the fluid collides with the tow. Therefore, the distance between the fluid nozzles when the fluid is sprayed is determined by the desired groove and the groove on the surface of the groove formed on the toe web. It can arrange | position according to the space | interval of a groove part.

The conditions for spraying the fluid are, for example, when the fluid is water vapor, the ejection pressure: about 0.1 to about 0.9 MPa, the water vapor temperature: about 110 to about 170 ° C., and the distance between the nozzle and the support: about 1 0.0 to about 5.0 mm. In addition, when the fluid is heated air, for example, air of about 105 ° C. and an air volume of about 1200 L / min is blown from a plurality of nozzles arranged with a diameter of 1.0 mm and a pitch of 6.0 mm. it can.
Moreover, in order to entangle the tow fibers, it is preferable that the tension for pulling the tow is not so high.

As the liquid-permeable top sheet according to the present invention, those usually used in the art can be selected without particular limitation, and examples thereof include non-woven fabrics, woven fabrics, and all or part thereof. Is a liquid-permeable resin film in which a large number of liquid-permeable holes are formed, and a net-like sheet having a large number of meshes. Examples of the nonwoven fabric include spunlace nonwoven fabric formed from cellulose fibers such as rayon, synthetic resin fibers, and the like, and air-through nonwoven fabric formed from the synthetic resin fibers.
Examples of the resin film and net-like sheet include those formed from polypropylene, polyethylene, polyethylene terephthalate, and the like.

As the liquid-impermeable back sheet according to the present invention, those usually used in the art can be used without particular limitation, and examples thereof include a low-density polyethylene sheet.
In the absorbent article of the present invention, the leakage barrier is an optional element and, if present, can be similar to the topsheet.

In the present invention, the desired superabsorbent polymer may be a polymer usually used in the art, for example, a synthetic polymer-based absorbent material such as starch-based, cellulose-based, polyacrylic acid-based, polyvinyl alcohol-based, Examples include acrylamide-based and polyoxyethylene-based absorbent materials. As the superabsorbent polymer, a polyacrylic acid-based absorbent is preferable, and among them, a sodium polyacrylate-based absorbent is preferable.
In the present invention, the core wrap as desired includes those usually used in the art, such as tissue, hydrolyzed tissue, and non-woven fabric (SMS, SB, etc.).

  Examples of the absorbent article of the present invention include disposable diapers, incontinence pads, sanitary napkins, panty liners, etc., but in the absorbent article of the present invention, the web made of tow has excellent liquid diffusibility, and Disposable diapers, incontinence pads, and sanitary napkins that absorb large amounts of liquid are particularly preferred because they are less likely to deform after absorbing liquid.

Hereinafter, although an example is given and the present invention is explained, the present invention is not limited to these examples.
[Production Example 1]
A tow (cellulose acetate, fiber diameter: 3.5 dtex) was molded to a basis weight of 50 g / m ² and a support comprising a round hole 60 ° staggered punching plate (φ: 0.75 mm, pitch: 1.2 mm) The nozzle is mounted on a steam treatment system (jet pressure: 0.70 Mpa, steam temperature: 170 ° C., steam pressure: 1.47 Kpa) having a plurality of nozzles (φ: 0.5 mm) at intervals of 2.0 mm. And while maintaining the distance between the supports at 2.0 mm, it was passed at a speed of 5 m / min. 1 was obtained.

  Tow-containing sample no. The photograph of 1 is shown in FIG.9 and FIG.10. 9 shows tow-containing sample No. 1 is a photograph taken with the groove surface facing the front, and FIG. 1 is a photograph taken from a cross-sectional direction. 9 and 10, MD indicates the conveyance direction, and coincides with the direction in which the flange portion 2, the groove portion 3, and the tow fibers are oriented. CD indicates an orthogonal direction. Although it is difficult to distinguish from the photograph, the tow-containing sample No. 1 had a plurality of entanglement points.

In addition, tow-containing sample No. 1, the height of the ridge was about 1.5 mm, and the height of the groove was about 0.3 mm.
The thickness was measured in a non-contact manner using a laser displacement meter. As the laser displacement meter, a high-precision two-dimensional laser displacement meter LJ-G series (model: LJ-G030) manufactured by Keyence Corporation was used.

[Production Example 2]
The tow (basis weight: 50 g / m ² ) molded in Production Example 1 was added to the tow-containing sample No. 2.

[Example 1]
[Break strength and elongation at break]
Tow-containing sample no. 1 and no. 2 is 25 mm in the direction in which the fibers are oriented (corresponding to the conveying direction MD in FIG. 9), and 100 mm in the direction perpendicular to the orientation of the fibers (corresponding to the orthogonal direction CD in FIG. 9). It cut so that it might have, and measured the above-mentioned breaking strength and elongation at break. For the measurement, FGC-0.2 manufactured by SHIMPO was used. The results are shown in Table 1 below.

  From Table 1, tow-containing sample No. No. 1 is a tough-containing sample No. 1 2.5 times higher than 2. This is tow-containing sample No. It is considered that 1 is caused by having a plurality of entanglement points.

[Example 2]
[Liquid diffusion length]
Tow-containing sample no. 1 and no. The liquid diffusion length and water absorption of 2 were evaluated according to the methods described herein. The results are shown in Table 2 below.

  Tow-containing sample no. No. 1 has a liquid diffusibility equal to or higher than that of the tow-containing sample No. 2 having a high liquid diffusibility. The water absorption rate is also equivalent.

[Example 3]
[Thickness retention and thickness retention when containing water]
Tow-containing sample no. 1 and no. The thickness retention rate of 2 and the thickness retention rate when containing water were evaluated according to the methods described herein. The results are shown in Table 3 below.

  From Table 3, tow-containing sample No. 1 shows tow-containing sample No. 1; It can be seen that both the thickness retention ratio and the moisture retention ratio are excellent compared to 2.

1 tow web 2 ridge part 3 groove part 4 toe fiber 5 entanglement point 6 ridge groove surface 7 absorbent article 8 top sheet 9 leakage barrier 10 tape fastener 11 absorbent body 12 back sheet 13 super absorbent polymer 14 second sheet 15 Third sheet 16 Toe 17 Support 18 Fluid nozzle L Longitudinal direction O Tow fiber orientation direction MD Conveyance direction CD Orthogonal direction

Claims (12)

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 , from tow A method for producing a web comprising :
Comprises providing the door window to form the web of the toe, and the preparative c, the fluid, by spraying along the orientation direction of the fibers of the tow, the preparative c, a plurality of ridges, thereby forming a plurality of grooves, entangling the fibers of the tow, along the orientation direction of the fibers of the tow has a ridge groove surface that includes a plurality of ridges and a plurality of grooves, and a plurality of intertwined point Forming a web comprising the tow ,
The said manufacturing method including. In the step of forming the web of the toe, said fluid is a heated air or steam, the production method according to claim 1. In the step of forming the web of the tow, the water vapor as the fluid ejection pressure of 0.1～0.9MPa, and at a temperature of 110 to 170 ° C., sprayed onto the preparative window, to claim 1 or 2 The manufacturing method as described. The said absorbent article WHEREIN: The web which consists of the said tow | toe is arrange | positioned so that the orientation direction of the fiber of the said tow | toe and the longitudinal direction of the said absorbent article may correspond. The manufacturing method as described in. The production method according to any one of claims 1 to 4 , wherein in the web of the absorbent article made of the tow, the amount of fibers in the collar portion is larger than the amount of fibers in the groove portion. The manufacturing method as described in any one of Claims 1-5 in which the said absorber contains the web which consists of the said tow | toe in the said absorbent article . In the absorbent article, the absorbent body further comprises a superabsorbent polymer, said superabsorbent polymer, than the ridge of the web of the toe, is abundant in the groove, according to claim 6 Manufacturing method . The absorbent article includes the top sheet, a second sheet disposed between the top sheet and the absorbent body, the web comprising the tow , and / or the absorbent article. but wherein the absorbent body, a third sheet being disposed between said backsheet, including those comprising a web of the tow, the production method according to any one of claims 1-7 . In the said absorbent article, the liquid diffusion length of the web which consists of the said tow | toe is 40 mm or more in the orientation direction of the fiber of the said tow | toe, The manufacturing method as described in any one of Claims 1-8 . The manufacturing method according to any one of claims 1 to 9 , wherein in the absorbent article, the web made of the tow has a thickness retention of 60% or more. The manufacturing method according to any one of claims 1 to 10 , wherein in the absorbent article, the web made of the tow has a thickness retention of 60% or more when containing water. Web of the tow in the absorbent article, as compared to the toe, with respect to the direction perpendicular to the orientation direction of the fibers of the tow have a breaking strength of at least 1.5 times, more of claims 1 to 11 the process according to one paragraph or.