WO2021079400A1

WO2021079400A1 - Absorbent article

Info

Publication number: WO2021079400A1
Application number: PCT/JP2019/041283
Authority: WO
Inventors: 真悟永田; 雅人重松
Original assignee: 株式会社ダイセル
Priority date: 2019-10-21
Filing date: 2019-10-21
Publication date: 2021-04-29
Also published as: CN114173733A

Abstract

This absorbent article comprises: an absorbent member that is in a sheet form and that absorbs moisture; and an opened fiber body that is disposed overlapping the absorbent member and that contains a plurality of long fibers which have been crimped and opened. The porosity of the opened fiber body is in a range of at least 87% to less than 100%.

Description

Absorbent article

The present invention relates to an absorbent article.

Absorbent articles such as disposable diapers and urine leakage prevention pads have, for example, a structure in which an absorbent body having water absorbency is covered with a top sheet and a back sheet. The absorber has, for example, a first absorbent material and a second absorbent material arranged on top of the first absorbent material, as disclosed in Patent Document 1. In this absorbent article, moisture reaches the absorber through the topsheet. Moisture passes through the second absorber while diffusing and is absorbed by the first absorber.

Japanese Unexamined Patent Publication No. 2006-14883

It is desirable that the absorbent article is bulky and has a good tactile sensation and a good usability (cushioning property) before and after water absorption, for example. However, the absorbent article of Patent Document 1 is not sufficiently bulky. For this reason, a phenomenon in which water seeps out to the surface after water absorption (hereinafter referred to as rewet) may occur and the tactile sensation may be deteriorated. In addition, this absorbent article has a relatively thin thickness and low resilience. Therefore, the user's usability is not sufficient.

Therefore, an object of the present invention is to make it possible to maintain a bulky state with a good usability before and after water absorption in an absorbent article provided with an absorbent body having water absorption.

In order to solve the above-mentioned problems, the absorbent article according to one aspect of the present invention is a plurality of absorbent articles which are arranged so as to be overlapped with a sheet-shaped absorbent member which absorbs moisture and the absorbent member, and are crimped and opened. The open fiber containing the long fibers of the above is provided, and the porosity of the open fiber is a value in the range of 87% or more and less than 100%.

According to the above configuration, the spread fiber contains a plurality of crimped and opened long fibers, and the porosity is a value in the range of 87% or more and less than 100%. Since the porosity of the spread fiber is relatively high as described above, the spread fiber can be bulky. In addition, abundant fiber gaps can be formed inside the spread fiber body. Therefore, even after the absorbent article has absorbed water, the moisture can be allowed to pass through the fiber gaps of the spread fiber while maintaining the bulky state of the absorbent article. As a result, water can be quickly absorbed in a wide range of the absorbing member. Further, since water does not easily collect on the upper surface of the spread fiber body, it is possible to prevent rewetting from occurring. Thereby, a good tactile sensation of the absorbent article can be maintained.

In addition, the good bulkiness of the spread fiber can be maintained even during use. Therefore, even when the absorbent article in use is compressed or absorbs water, the form of the absorbent article can be maintained together with the excellent resilience of the absorbent article. As a result, it is possible to maintain fiber gaps through which water flows in the spread. Further, since the spread fiber has a good bulkiness, the thickness dimension of the absorbent article can be increased. Therefore, a good feeling of use of the absorbent article can be maintained before and after water absorption.

The long fibers may be cellulose acetate fibers. According to this structure, the spread fiber can be bulky. In addition, the affinity between the spread fiber and water can be improved. Therefore, water can be quickly taken in and dispersed in the spread fiber. As a result, the occurrence of rewetting can be better prevented, and the usability of the absorbent article can be improved.

The content of the binder contained in the spread fiber may be a value in the range of 0% by weight or more and 10% by weight or less. As a result, it is possible to prevent the plurality of long fibers in the spread fiber from becoming difficult to move relative to each other due to the binder. Therefore, the soft and soft touch of the absorbent article can be maintained. In addition, it is possible to prevent the binder from deteriorating the tactile sensation of the absorbent article.

The absorbing member may have a pulp sheet and water-absorbing granules dispersed in the pulp sheet. As a result, the water that has passed through the spread fiber can be rapidly absorbed by each of the granules dispersed in the pulp sheet. Therefore, for example, it is possible to prevent rewetting from occurring due to local accumulation of water in the absorbing member.

When the basis weight of the spread fiber is in ^{the range of 80 g / m 2} or more and 100 g / m ² or less, the compression energy WC in a state where the thickness dimension is compressed to 50% from the natural state is 1.9 gfm. The value may be in the range of less than / cm ^2. Further, when the basis weight of the spread fiber is in ^{the range of 50 g / m 2} or more and less than 80 g / m ² , the compression energy WC in the state where the thickness dimension is compressed to 50% from the natural state is 1. The value may be in the range of less than 7 gfm / cm ^2. Further, when the basis weight of the spread fiber is in ^{the range of 20 g / m 2} or more and less than 50 g / m ² , the compression energy WC in the state where the thickness dimension is compressed to 50% from the natural state is 1. The value may be in the range of less than 3 gfm / cm ^2. Further, when the basis weight of the spread fiber is in ^{the range of less than 20 g / m 2} , the compression energy WC in the state where the thickness dimension is compressed to 50% from the natural state is less than ^{1.2 gfm / cm 2.} It may be a value in the range of.

According to each of these configurations, it is possible to prevent the shape of the spread fiber from collapsing even when a load is applied to the absorbent article during use. Therefore, even in the absorbent article in use, the entangled state of the fibers in the spread fiber and the abundant fiber gap can be maintained. Therefore, the water absorption time for the spread fiber to absorb water can be shortened. In addition, it is possible to suppress the time required for water absorption when the spread fiber is repeatedly absorbed. In addition, it is possible to prevent the resilience of the absorbent article from being reduced during use. As a result, the performance of the absorbent article can be maintained even after long-term use.

A breathable back sheet arranged on the side of the absorbent member opposite to the spread member and a liquid-permeable top arranged on the side of the spread member opposite to the absorbent member. A seat may be further provided. As a result, while holding the spread fiber body and the absorbing member by the back sheet and the top sheet, the spread fiber body can efficiently absorb water through the top sheet. In addition, it is possible to prevent the water absorbed by the absorbing member from leaking to the outside through the back sheet.

According to each aspect of the present invention, in an absorbent article provided with an absorbent body having water absorption, it is possible to maintain a bulky and good usability state before and after water absorption.

It is sectional drawing of the absorbent article which concerns on 1st Embodiment. It is the schematic of the manufacturing apparatus of the absorbent article which concerns on 1st Embodiment. It is sectional drawing of the absorbent article which concerns on 2nd Embodiment. It is an enlarged photograph of the spread fiber body which concerns on Example 21. It is an enlarged photograph of the spread fiber body which concerns on Example 22. It is an enlarged photograph of the spread fiber body which concerns on Comparative Example 6. It is an enlarged photograph of the spread fiber body which concerns on Comparative Example 7.

Hereinafter, each embodiment will be described with reference to the drawings. The upstream side referred to below refers to the upstream side of the tow band 61 in the transport direction P, and the downstream side refers to the downstream side of the tow band 61 in the transport direction P.

(First Embodiment)
[Absorbent article]
FIG. 1 is a cross-sectional view of the absorbent article 1 according to the first embodiment. As shown in FIG. 1, the absorbent article 1 is formed in a sheet shape as a whole. The absorbent article 1 includes a back sheet 2, an absorbing member 3, a spread fiber 4, and a top sheet 5. These components 2 to 5 are arranged in order from the lower side to the upper side of the absorbent article 1. The absorbent article 1 has a structure in which the absorbing member 3 and the spread fiber 4 are covered with the back sheet 2 and the top sheet 5 in a state where the absorbing member 3 and the spread fiber 4 are arranged in an overlapping manner.

The top sheet 5 covers the upper surface of the spread fiber 4 and allows moisture to permeate. The top sheet 5 is arranged so as to be overlapped on the side opposite to the absorbing member 3 of the spread fiber 4. The top sheet 5 is a resin film having porosity. The top sheet 5 may be a non-woven fabric having liquid permeability.

The back sheet 2 has breathability, covers the lower surface of the absorbing member 3, and supports the absorbing member 3 from below. The back sheet 2 is arranged so as to be overlapped on the side opposite to the spread fiber 4 of the absorbing member 3 to prevent the moisture in the absorbing member 3 from leaking to the outside. The back sheet 2 is, for example, a resin film having liquid impermeable property.

The absorbing member 3 has water absorption and is formed in a sheet shape. As an example, the absorbing member 3 of the present embodiment has a pulp sheet 6 and a granular material 7 having water absorption dispersed in the pulp sheet 6. Granule 7 contains a super absorbent polymer (SAP) as an example. The granules 7 are dispersed and arranged in the fiber gaps of the pulp sheet 6 and are held by the pulp fibers of the pulp sheet 6. The configuration of the absorbing member 3 is not limited to this.

The spread fiber 4 is arranged so as to overlap the absorbing member 3. The spread fiber 4 contains a plurality of long fibers that have been crimped and opened. The spread fiber 4 is molded into a sheet shape. The spread fiber 4 has an elongated shape as an example. The thickness dimension of the spread fiber 4 can be set as appropriate. The thickness dimension of the spread fiber 4 may be larger or smaller than, for example, the thickness dimension of the absorbing member 3. The long fibers contained in the spread fiber 4 are cellulose acetate fibers as an example. The fibers contained in the spread fiber 4 may be other fibers such as rayon and synthetic fibers. The total fineness (total denier: TD) and the single fineness (filament denier: FD) of the spread fiber 4 can be appropriately set.

As an example, the spread fiber 4 has a thickness dimension in the range of 0.6 mm or more and 15.0 mm or less. The spread fiber 4 has a basis weight in the range of ^{100 g / m 2 or less.} Further, the spread fiber 4 has a value in the range of ^{100 cm 2} or more and 900 cm ^{2 or less in the area when viewed in a plan view.}

The spread fiber 4 is opened in a state in which a plurality of crimped fibers are entangled with each other. As a result, the spread fiber 4 has abundant fiber gaps. The porosity of the spread fiber 4 is set to a value in the range of 87% or more and less than 100%. The porosity (%) referred to here is calculated from the formula {100- (V ₂ / V ₁ ) × 100} _{based on the spread fiber volume V 1} _{and the total fiber volume V 2} in the spread fiber body 4. Is the value to be. The volume V ₂ is calculated based on the ratio M / D of the total fiber weight M and the fiber density D. Further, the volume V ₁ can be calculated based on, for example, the projected area of each surface of the spread fiber 4.

The entanglement of the fibers of the spread fiber 4 is uniform in all directions. In the spread fiber 4, a plurality of fibers are sufficiently entangled with each other. Therefore, the spread fiber 4 is rich in resilience. Further, the spread fiber 4 has substantially the same tensile strength in the vertical direction and the width direction per unit volume, for example.

Further, in the absorbent article 1 of the present embodiment, the spread fiber 4 has a compression energy WC in the range of less than ^{1.9 gfm / cm 2 in a state where the thickness dimension is compressed to 50% from the natural state.} .. Further, the compression energy WC in the state where the thickness dimension of the spread fiber 4 is compressed to 50% is a value in the range ^{where the basis weight of the spread fiber 4 is 50 g / m 2} or more and less than 80 g / m ^2. At one time, ^{the value is in the range of less than 1.7 gfm / cm 2} , and when the basis weight of the spread fiber 4 is in the range of 20 g / m ² or more and less than 50 g / m ^2, it is less than 1.3 gfm / cm ^2. It is a value in the range of 1.2 gfm / cm ² when the basis weight of the spread fiber 4 is a value in the range of ^{less than 20 g / m 2} .

By setting the value of the compression energy WC of the spread fiber 4 in this way, the spread fiber 4 is in the form of the absorbent article 1 even when a slight load is applied during the use of the absorbent article 1. Is retained to some extent. Therefore, the performance and usability of the absorbent article 1 are stably maintained. Further, by adjusting the value of the compression energy WC according to the basis weight of the spread fiber 4 as described above, appropriate good resilience (elasticity) is imparted to the spread fiber 4 set to different basis weights. At the same time, the form in use can be maintained.

The spread fiber 4 has strong entanglement between fibers. Therefore, in the spread fiber 4, a binder for binding the fibers to each other is basically unnecessary. In the present embodiment, the content of the binder contained in the spread fiber 4 is a value in the range of 0% by weight or more and 10% by weight or less. That is, the spread fiber 4 of the absorbent article 1 does not contain a binder, or even if it contains a binder, it contains only a small amount. Examples of the binder include known binders such as triacetin.

As described above, in the absorbent article 1, the spread fiber 4 contains a plurality of crimped and opened long fibers, and the porosity is a value in the range of 87% or more and less than 100%. Since the porosity of the spread fiber 4 is relatively high as described above, the spread fiber 4 can be configured to be bulky. In addition, abundant fiber gaps can be formed inside the spread fiber 4. Therefore, even after the absorbent article 1 has absorbed water, the absorbent article 1 can be passed while being diffused into the fiber gaps of the spread fiber 4 while maintaining the bulky state of the absorbent article 1. As a result, water can be quickly absorbed in a wide range of the absorbing member 3. Further, since water does not easily collect on the upper surface of the spread fiber 4, it is possible to prevent rewetting from occurring. Thereby, a good tactile sensation of the absorbent article 1 can be maintained.

In addition, the good bulkiness of the spread fiber 4 can be maintained even during use. Therefore, even when the absorbent article 1 in use is compressed or absorbs water, the form of the absorbent article 1 can be maintained together with the excellent resilience of the absorbent article 1. Thereby, the fiber gap through which water flows can be maintained in the spread fiber 4. Further, since the spread fiber 4 has a good bulkiness, the thickness dimension of the absorbent article 1 can be increased. Therefore, a good usability of the absorbent article 1 can be maintained before and after water absorption.

Further, in the present embodiment, the long fibers of the spread fiber 4 are cellulose acetate fibers. According to this structure, the spread fiber 4 can be made bulky. In addition, the affinity between the spread fiber 4 and water can be improved. Therefore, water can be quickly taken in and dispersed in the spread fiber 4. As a result, the occurrence of rewetting can be prevented more satisfactorily, and the usability of the absorbent article 1 can be improved.

Further, in the absorbent article 1, the content of the binder contained in the spread fiber 4 is a value in the range of 0% by weight or more and 10% by weight or less. As a result, it is possible to prevent the plurality of long fibers in the spread fiber 4 from becoming difficult to move relative to each other due to the binder, and it is possible to maintain the soft and soft touch of the absorbent article 1. In addition, it is possible to prevent the binder from deteriorating the tactile sensation of the absorbent article 1.

Further, the absorbing member 3 has a pulp sheet 6 and a granular material 7 having water absorption dispersed in the pulp sheet 6. As a result, the water that has passed through the spread fiber 4 can be rapidly absorbed by each of the granules 7 dispersed in the pulp sheet 6. Therefore, for example, it is possible to prevent rewetting from occurring due to local accumulation of water in the absorbing member 3.

Further, the spread fiber 4 has a compression energy WC in a range of less than ^{1.9 gfm / cm 2} in a state where the thickness dimension is compressed to 50% from the natural state. According to this configuration, it is possible to prevent the shape of the spread fiber 4 from collapsing even when a load is applied to the absorbent article 1 during use. Therefore, even in the absorbent article 1 in use, the entangled state of the fibers in the spread fiber 4 and the abundant fiber gaps can be maintained. Therefore, the water absorption time for the spread fiber 4 to absorb water can be shortened. Further, when the spread fiber 4 is repeatedly absorbed with water, it is possible to suppress the time required for water absorption. In addition, it is possible to prevent the resilience of the absorbent article 1 from being lowered during use. As a result, the performance of the absorbent article 1 can be maintained even when used for a long period of time.

Further, the absorbent article 1 is arranged so that the breathable back sheet 2 which is arranged so as to be overlapped on the side opposite to the fiber opening member 4 of the absorbent member 3 and the absorbent back sheet 2 which is arranged so as to be overlapped on the side opposite to the absorbent member 3 of the fiber opening member 4. It is provided with a top sheet 5 having a liquid permeability. As a result, while the fiber-spreading body 4 and the absorbing member 3 are held by the back sheet 2 and the top sheet 5, the fiber-spreading body 4 can efficiently absorb water through the top sheet 5. Further, it is possible to prevent the water absorbed by the absorbing member 3 from leaking to the outside through the back sheet 2. A liquid-permeable member may be separately provided between the top sheet 5 and the spread fiber 4 and at least between the spread fiber 4 and the absorbing member 3.

[Absorbent article manufacturing equipment]
FIG. 2 is a schematic view of the absorbent article manufacturing apparatus 20 (hereinafter, also simply referred to as manufacturing apparatus 20) according to the first embodiment. As shown in FIG. 2, a packing container 60 is arranged in the vicinity of the manufacturing apparatus 20. In the packing container 60, a tow band 61 containing a plurality of crimped long fibers is folded and compressed into a veil shape and packed. The packing container 60 of FIG. 2 shows a cross-sectional structure.

The fibers contained in the tow band 61 are long fibers of crimped cellulose acetate tow. In the manufacturing apparatus 20 of the present embodiment, the toe band 61 is transported in a predetermined transport direction P while being held horizontally in the width direction.

The manufacturing apparatus 20 includes a first manufacturing unit 22 and a second manufacturing unit 23. The first manufacturing unit 22 includes a first widening device B1, a guide 25, a second widening device B2, a first spread fiber pair 26, a second fiber spreader roll pair 27, a gas fiber spreader pair 28, and a transfer roll pair 29. Have.

The widening devices B1 and B2 widen the toe band 61 in the width direction. The guide 25 guides the tow band 61 that has passed through the first widening device B1 toward the second widening device B2. The fiber-spreading roll pairs 26 and 27 further spread the tow band 61 that has passed through the second widening device B2 on the upstream side of the gas fiber-spreading device 28. The second spread roll pair 27 is arranged on the downstream side of the first spread fiber pair 26. The first spread fiber pair 26 has a pair of

rolls

30, 31. The second spread roll pair 27 has a pair of

rolls

32, 33. The

rolls

32 and 33 rotate at a peripheral speed faster than the peripheral speed of the

rolls

30 and 31.

The toe band 61 that has passed through the second widening device B2 is inserted between the pair of

rolls

30 and 31 and between the pair of

rolls

32 and 33. By contacting the peripheral surfaces of the rolls 30 to 33, the toe band 61 is tensioned in the transport direction P and is bulky and opened.

The gas spreading device 28 spreads the tow band 61 that has passed through the second spreading roll pair 27. The gas spreading device 28 has a main body portion 50, a fiber spreading molding portion 51, and a retention portion 52. The main body 50 mixes a gas G (air as an example) supplied from the outside and a tow band 61. The fiber-spreading molding section 51 spreads and molds the tow band 61 that has passed through the main body section 50 with the gas G. The retention portion 52 has a plurality of long members 53 extending in the transport direction P and arranged in the circumferential direction of the toe band 61. The retention portion 52 temporarily retains the toe band 61 that has passed through the spread-spread molding portion 51 to adjust the density and bulkiness of the toe band 61. The inlet and outlet of the main body 50 are circular. The inlet of the spread fiber molding portion 51 has a circular shape, and the outlet has a flat shape in which the width direction of the toe band 61 is larger than that in the vertical direction.

The tow band 61 introduced into the gas spreading device 28 is mixed with the gas G introduced from the outside from the direction perpendicular to the transport direction P in the transport direction in the internal space 50a provided in the main body 50 in all directions. It is transported to P and discharged from the main body 50. As a result, the volume of the toe band 61 expands and the density decreases. The tow band 61 that has passed through the main body portion 50 is opened and molded while being expanded in the width direction by passing through the flat fiber opening chamber 51a having a flow path cross section provided in the fiber opening molding portion 51. To. As a result, the tow band 61 is bulky and uniformly spread as compared with the case where it passes through a fiber-spreading device having a constant width direction, for example. Further, the entanglement of the long fibers in the toe band 61 becomes uniform in all directions of the toe band 61, and the degree of entanglement is improved.

The tow band 61 that has passed through the spread fiber molding portion 51 temporarily stays in the retention chamber 52a provided in the retention portion 52, so that the density and bulkiness can be increased while maintaining the cross-sectional shape perpendicular to the transport direction P. It will be adjusted. For details of the gas spreading apparatus 28, for example, Japanese Patent No. 5526109 can be referred to.

The transport roll pair 29 has transport rolls 34 and 35 arranged so that their peripheral surfaces face each other. The tow band 61 that has passed through the gas spreading device 28 is inserted between the transport rolls 34 and 35 and pressed by the transport rolls 34 and 35 in the thickness dimension direction. As a result, the sheet-shaped spread fiber 4 is manufactured. The spread fiber 4 is conveyed to the second manufacturing unit 23 while being guided by the guide roll 36.

The second manufacturing unit 23 manufactures the absorbent article 1 by arranging the absorbing member 3 and the spread fiber 4 so as to overlap each other and covering them with the top sheet 5 and the back sheet 2. The second manufacturing unit 23 includes a roll R1 around which the back sheet 2 is wound, a roll R2 around which the top sheet 5 is wound, and a roll R3 around which the pulp sheet 6 is wound. The second manufacturing unit 23 includes guide rolls 37 and 38, a first supply device 40, a second supply device 41, a transfer roll pair 42, a sheet molding roll pair 43, and a sheet transfer device 44.

The first supply device 40 supplies the granules 7 to the pulp sheet 6 so as to diffuse the granules 7 into the strip-shaped pulp sheet 6 that is fed out from the roll R3 and conveyed on the transport line L. As a result, the band-shaped absorbing member 3 is formed. The band-shaped absorbing member 3 is supported from below by the band-shaped back sheet 2 that is fed out from the roll R1 and conveyed on the conveying line L, and is overlapped with the fiber opening body 4 from above. The laminated body composed of the back sheet 2, the absorbing member 3, and the spread fiber 4 passes between the

rolls

45 and 46 of the transport roll vs. 42 and is transported to the downstream side.

Next, the laminated body is overlapped with the top sheet 5 which is fed out from the roll R2, guided by the guide roll 38, and conveyed on the transfer line L. The surface of the top sheet 5 on the back sheet 2 side is preliminarily coated with an adhesive by the second supply device 41. The back sheet 2, the absorbing member 3, the spread fiber 4, and the top sheet 5 are molded into a sheet shape as a whole by passing between the

rolls

47 and 48 of the sheet molding roll vs. 43. Further, the top sheet 5 and the back sheet 2 are adhered by passing through the sheet transport device 44. Then, these components 2 to 5 are cut to a predetermined size to obtain the absorbent article 1.

As described above, the method for producing the absorbent article 1 of the present embodiment includes a fiber-spreading body forming step of forming the fiber-spreading body 4 by opening and molding the tow band 61, and absorption for forming the absorbing member 3. It has a member forming step and an adhesion step of adhering the back sheet 2 and the top sheet 5 in a state where the absorbing member 3 and the spread fiber 4 are arranged so as to be overlapped between the back sheet 2 and the top sheet 5. By going through each of these steps, an absorbent article 1 having a porosity in the range of 87% or more and less than 100% and having a bulky spread fiber 4 is obtained.

Here, in the spread fiber forming step of the present embodiment, a tow band 61 composed of a plurality of crimped cellulose acetate fibers is used. Further, in the spread fiber forming step, after mixing the tow band 61 and the gas G in all directions perpendicular to the transport direction P of the tow band 61 to be transported, the width dimension is larger than the vertical dimension and the downstream side of the transport direction P. The tow band 61 is opened and molded by the gas G in the opening chamber 51a in which the dimension in the width direction increases toward. At this time, the tow band 61 is pressed against the inner peripheral surface of the fiber opening chamber 51a for molding. Further, in the absorption member forming step, the absorption member 3 is formed by adding the water-absorbent granules 7 to the pulp sheet 6. Hereinafter, the second embodiment will be described focusing on the differences from the first embodiment.

(Second Embodiment)
FIG. 3 is a cross-sectional view of the absorbent article 11 according to the second embodiment. The absorbent member 8 of the absorbent article 11 has a support sheet 9 made of a non-woven fabric and a granular material 7 fixed to one side (here, the upper surface) of the support sheet 9. The granular material 7 is fixed to the support sheet 9 with an adhesive (for example, a hot melt type adhesive). Even with the absorbent article 11 having such a configuration, the same effect as that of the absorbent article 1 can be expected. Further, since the granules 7 do not move during use, it is possible to prevent the water absorption of the absorbent article 11 from being unevenly distributed, and the absorbent article 11 can be used stably. The structure for fixing the granular material 7 to the support sheet 9 does not have to be a structure using an adhesive.

(Confirmation test)
Next, the confirmation test will be described, but the present invention is not limited to the examples shown below.
[Appearance / tactile evaluation test]
Using the absorbent article manufacturing apparatus 20 of the first embodiment, the spread fiber 4 made of cellulose acetate fibers having a single fineness of 6 and having a basis weight of 50 g / m ² and a porosity of 99% is used. Manufactured as Example 1. Further, it is the same as the absorbent article manufacturing apparatus 20 except that a thickening device for expanding the veil-shaped toe band by applying air only from the vertical direction perpendicular to the conveying direction P is used instead of the gas spreading device 28. An spread fiber having a porosity of 85% was produced as Comparative Example 1 using an absorbent article manufacturing apparatus having the above structure. The bulkiness of the obtained spread fibers of Example 1 and Comparative Example 1 was visually evaluated, and the tactile sensation was evaluated by hand. As a result, it was found that Example 1 had a bulkier and softer feel than Comparative Example 1.

[Water absorption time measurement test under load]
Next, Examples 1 and Comparative Example 1 were tested according to the following procedure. The spread fiber of Example 1 or Comparative Example 1 is placed between the absorption core (equivalent to an absorbent member) and the surface sheet (equivalent to a top sheet) of a commercially available absorbent article (baby diaper manufactured by Daio Paper Corporation). Placed. A plate having an opening was placed on top of the surface sheet, and a weight (2 kg) was placed on the plate to apply a constant load to the spread fibers of Example 1 and Comparative Example 1.

With the load applied to the spread fiber body in this way, 80 cc of physiological saline was dropped onto the spread fiber body through the opening of the plate. Then, the time from the dropping to the complete absorption of water was measured as the first water absorption time. Five minutes after the dropping, the plate and the weight were removed, the filter paper was placed on the surface sheet, and the weight (3.5 kg) was placed on the filter paper to remove excess water. Three minutes after placing the filter paper and the weight, the filter paper and the weight were removed. Two minutes later, a plate and a weight (2 kg) were placed on the plate and dropped by the same method as the first, and the second water absorption time was measured. According to this test, it can be evaluated that the shorter the water absorption time (in other words, the faster the water absorption rate), the higher the water absorption performance. The results of this measurement test are shown in Table 1.

[Table 1]

As shown in Table 1, it was confirmed that the water absorption time of Example 1 can be shorter than that of Comparative Example 1 in both the first water absorption and the second water absorption. The reason for this is that the spread fiber 4 of Example 1 has a higher porosity than that of Comparative Example 1, so that it is considered that the physiological saline solution in the fiber gap could be rapidly circulated and absorbed into the absorption core. .. Further, since the spread fibers 4 of Example 1 have stronger entanglement between fibers as compared with Comparative Example 1, it is considered that the fiber gaps can be stably maintained even if water is repeatedly absorbed. Further, according to this test, in the absorbent article 1 using the spread fiber 4 of Example 1, it is considered that the spread fiber 4 can rapidly absorb water, so that it is possible to prevent water from leaking during use.

[Porosity measurement test]
The size in plan view is constant (38 cm × 11 cm) and the fiber density is constant (1.32 g / cm ³ ), and the spread _{fiber volume V 1} , the total fiber volume V ₂ , the thickness dimension, and the basis weight are changed. The spread fiber 4 was produced as Examples 2 to 16. In Examples 2 to 16, the thickness dimension of the spread fiber 4 is changed in the range of 0.6 mm or more and 15 mm or less (here, it is changed to either 0.6 mm, 5 mm, or 15 mm), and the basis weight is 20 g. / ^{m 2} or more 100 g / ^m was ² varied in the following range. Also has a size that is the same plan view as in Example 2 to 16 were produced small open繊体opens繊体volume V ₁ as compared to Examples 2 to 16 as Comparative Examples 2-4. The porosities of Examples 2 to 16 and Comparative Examples 2 to 4 were examined. The measurement results are shown in Tables 2-5.

[Table 2]

[Table 3]

[Table 4]

[Table 5]

As shown in Tables 2 to 5, in Examples 2 to 16, the porosity was in the range of 87% or more and less than 100%, and it was found that the porosity was larger than that of Comparative Examples 2 to 4. On the other hand, in Comparative Examples 2 to 4, the porosity remained at 85%. From this, it was found that Examples 2 to 16 were relatively bulky and had a high porosity. Further, as shown in this result, the porosity of the open繊体, for example, was found to be adjustable by adjusting the thickness and open繊体volume V ₁ of the Open繊体. Further, as in Examples 2 to 16, the thickness dimension of the spread fiber 4 is set to a value in the range of 0.6 mm or more and 15 mm or less, and the basis weight is set to a value in the range of 20 g / m ² or more and 100 g / m ² or less. It was found that it is easy to stably produce the spread fiber 4 having the target porosity.

[Compression test]
Using the absorbent article manufacturing apparatus 20 of the first embodiment, it is composed of cellulose acetate fibers having a single fineness of 3 or 6, and has a basis weight of 20 g / m ² , 50 g / m ² , 80 g / m ² , or 100 g / m ^2. The spread fiber 4 (porosity 99%) set in the above was produced as Examples 17 to 24. The compression test was performed on Examples 17 to 24 based on the KES (Kawabata Evaluation System) method, and the compression energy WC was measured.

Specifically, a commercially available compression tester (compression tester "KES-G5" manufactured by Kato Tech Co., Ltd.) was used, and the measurement conditions were as follows: compression speed 0.01 cm / sec, compression area 2 cm ² , sensitivity (SENS). ) 2, the upper limit load was set to ^{50 gf / cm 2.} Then, by pressing the spread fiber body with the non-woven fabric sheet, a load is applied to the entire spread fiber body, and the spread fiber body is fixed to the pedestal in a state of being compressed to 50% of the initial thickness dimension (thickness dimension in the natural state). , The compression energy WC was measured. It can be evaluated that the larger the value of the compression energy WC is, the softer it is, and conversely, the smaller the value is, the more elastic it is. The measurement results are shown in Table 6.

[Table 6]

As shown in Table 6, it was confirmed that in each of Examples 17 to 24, the compression energy was sufficiently small and the elasticity was good. As a result, it is considered that Examples 17 to 24 are soft until a constant load is applied and are not easily crushed after a constant load is applied. Further, the absorbent article 1 using the spread fiber 4 of Examples 17 to 24 has good resilience (elasticity), can hold a good shape even when a load is applied during use, and loses its shape. It is considered difficult to do.

The reason why such a result was obtained is that in Examples 17 to 24, the tow band 61 was opened by the gas G during the production of the spread fiber 4, so that the fibers of the spread fiber 4 were relatively entangled with each other. It is considered that the fiber opening body 4 is stronger and the internal structure of the fiber opening body 4 is less likely to change even if a slight load is applied to the fiber opening body 4, and the shape of the fiber opening body 4 is maintained.

Further, from the results of the compression test, according to the absorbent article 1 using the spread fiber 4 of Examples 17 to 24, a tactile sensation having excellent flexibility can be exhibited in a state where a compressive load is not applied (initial state). it is conceivable that. Further, in a state where a compressive load is applied (used state), it is considered that the morphology can be maintained and good resilience can be exhibited. As a result, it is considered that the absorbent article 1 can prevent liquid leakage by suppressing excessive compression of the spread fiber 4 during use, and can stably exhibit water absorption.

According to another compression test conducted by the inventors, the spread fiber 4 has a thickness dimension of 50 from the natural state when the ^{basis weight is in the range of 80 g / m 2} or more and 100 g / m ^{2 or less.} It was confirmed that the compression energy WC in the state of being compressed to% was in the range of less than ^{1.9 gfm / cm 2.} Further, when the basis weight of the spread fiber 4 is ^{a value in the range of 50 g / m 2} or more and less than 80 g / m ² , the compression energy WC in the state where the thickness dimension is compressed to 50% from the natural state is 1. It was also confirmed that the value was in the range of less than 7 gfm / cm ^2. Further, when the basis weight of the spread fiber 4 is ^{a value in the range of 20 g / m 2} or more and less than 50 g / m ² , the compression energy WC in the state where the thickness dimension is compressed to 50% from the natural state is 1. It was also confirmed that the value was in the range of less than 3 gfm / cm ^2.

From the results of such compression tests, it was confirmed that the value of compression energy changes depending on FD, basis weight, porosity, etc. Therefore, as a method of setting the compression energy of the spread fiber 4 as a target value, for example, a method of changing at least one of items such as FD, basis weight, and porosity can be considered.

Here, FIG. 4 is an enlarged photograph of the spread fiber 4 according to the twenty-first embodiment. FIG. 5 is an enlarged photograph of the spread fiber 4 according to the 22nd embodiment. FIG. 6 is an enlarged photograph of the spread fiber body according to Comparative Example 6. FIG. 7 is an enlarged photograph of the spread fiber body according to Comparative Example 7. Comparative Example 6 has a porosity of 85%, is a fiber-spreading body corresponding to Example 21, and has the same configuration as the absorbent article manufacturing device 20 except that the gas fiber-spreading device 28 is not used. It is a spread fiber produced by using an absorbent article manufacturing apparatus. Comparative Example 7 has a porosity of 85%, is a fiber-spreading body corresponding to Example 22, and has the same configuration as the absorbent article manufacturing device 20 except that the gas fiber-spreading device 28 is not used. It is a spread fiber produced by using an absorbent article manufacturing apparatus. FIGS. 4 to 7 show photographs of the spread fibers taken at a magnification of 35 times using a digital microscope "RH-2000" manufactured by Hirox Co., Ltd.

As shown in FIGS. 4 to 7, in the spread fibers 4 according to Examples 21 and 22, the fiber gaps and the entanglement between the fibers are omnidirectional as compared with the spread fibers according to Comparative Examples 6 and 7. It was confirmed that they were formed uniformly. Further, as shown in FIGS. 6 and 7, in Comparative Examples 6 and 7, regions where the fibers were considerably sparse were confirmed, but as shown in FIGS. 4 and 5, such regions were found in Examples 21 and 22. Not confirmed. From this result, it is considered that Examples 21 and 22 have overall uniform characteristics as compared with Comparative Examples 6 and 7.

The present invention is not limited to each embodiment and each embodiment, and its configuration and method can be changed, added, or deleted without departing from the spirit of the present invention. Various known additives such as a colorant may be added to the spread fiber 4.

As described above, according to the present invention, in an absorbent article provided with an absorbent body having water absorption, it has an excellent effect of being able to maintain a bulky and excellent usability before and after water absorption. Therefore, it is beneficial to widely apply it as an absorbent article capable of exerting the significance of this effect.

1,11 Absorbent article 2 Back sheet 3 Absorbent member 4 Spread fiber 5 Top sheet 6 Pulp sheet 7 Granules

Claims

A sheet-shaped absorbent member that absorbs moisture,
A fiber-spreading body containing a plurality of long fibers that are arranged so as to be overlapped with the absorbing member and crimped and spread.
An absorbent article in which the porosity of the spread fiber is a value in the range of 87% or more and less than 100%.
The absorbent article according to claim 1, wherein the long fibers are cellulose acetate fibers.
The absorbent article according to claim 1 or 2, wherein the content of the binder contained in the spread fiber is a value in the range of 0% by weight or more and 10% by weight or less.
The absorbent article according to any one of claims 1 to 3, wherein the absorbent member has a pulp sheet and water-absorbent granules dispersed in the pulp sheet.
When the basis weight of the spread fiber is in the range of 80 g / m 2 or more and 100 g / m 2 or less, the compression energy WC in a state where the thickness dimension is compressed to 50% from the natural state is 1.9 gfm. The absorbent article according to any one of claims 1 to 4, which has a value in the range of less than / cm 2.
When the basis weight of the spread fiber is in the range of 50 g / m 2 or more and less than 80 g / m 2 , the compression energy WC in the state where the thickness dimension is compressed to 50% from the natural state is 1.7 gfm. The absorbent article according to any one of claims 1 to 5, which has a value in the range of less than / cm 2.
When the basis weight of the spread fiber is in the range of 20 g / m 2 or more and less than 50 g / m 2 , the compression energy WC in the state where the thickness dimension is compressed to 50% from the natural state is 1.3 gfm. / cm is the value of 2 less than the range, the absorbent article according to any one of claims 1 to 6.
When the basis weight of the spread fiber is in the range of less than 20 g / m 2 , the compression energy WC in the state where the thickness dimension is compressed to 50% from the natural state is less than 1.2 gfm / cm 2. The absorbent article according to any one of claims 1 to 7, which is a value in the range.
A breathable back sheet arranged on the side of the absorbent member opposite to the spread member and a liquid-permeable top arranged on the side of the spread member opposite to the absorbent member. The absorbent article according to any one of claims 1 to 8, further comprising a sheet.