CN114173733A

CN114173733A - Absorbent article

Info

Publication number: CN114173733A
Application number: CN201980098741.9A
Authority: CN
Inventors: 永田真悟; 重松雅人
Original assignee: Daicel Corp
Current assignee: Daicel Corp
Priority date: 2019-10-21
Filing date: 2019-10-21
Publication date: 2022-03-11
Also published as: WO2021079400A1

Abstract

The absorbent article includes a sheet-like absorbent member that absorbs moisture, and a spread body that is arranged to overlap with the absorbent member and includes a plurality of crimped and spread long fibers. The void ratio of the opened fiber is a value in the range of 87% or more and less than 100%.

Description

Absorbent article

Technical Field

The present invention relates to an absorbent article.

Background

Absorbent articles exemplified as paper diapers, urine leakage preventing pads, and the like have, for example, the following structure: the absorbent body having water absorption properties is covered with a top sheet and a back sheet. For example, as disclosed in patent document 1, the absorbent body has a first absorbent member and a second absorbent member arranged to overlap the first absorbent member. In the absorbent article, moisture passes through the top sheet to reach the absorber. The moisture passes through the second absorbent while diffusing therein, and is absorbed by the first absorbent.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2006-14883

Disclosure of Invention

Problems to be solved by the invention

Ideally: the absorbent article is bulky before and after absorbing water, and has a good feeling of use such as touch and resiliency (cushioning). However, the absorbent article of patent document 1 is insufficient in bulkiness. Therefore, a phenomenon (hereinafter, referred to as "rewet") in which moisture seeps out on the surface after water absorption may occur, and the feel may be reduced. In addition, the absorbent article has a relatively thin thickness dimension and low resilience. Therefore, the user feels bad.

Therefore, an object of the present invention is to provide an absorbent article including an absorbent body having water absorption properties, which is capable of maintaining a bulky state and a good feeling of use before and after water absorption.

Technical scheme

In order to solve the above problems, an absorbent article according to one aspect of the present invention includes a sheet-like absorbent member that absorbs moisture, and a spread body that is arranged to overlap with the absorbent member and includes a plurality of crimped and spread long fibers, and that has a void ratio in a range of 87% or more and less than 100%.

According to the above configuration, the opened body includes a plurality of long fibers that are crimped and opened, and the void ratio is a value in a range of 87% or more and less than 100%. In this way, the void ratio of the opened fiber is a relatively high value, and therefore the opened fiber can be configured to be bulky. In addition, a large number of fiber gaps can be formed in the inside of the split fiber body. Therefore, even after the absorbent article absorbs water, the water can be passed through the fiber gaps of the opened fibers while being diffused, while maintaining the bulky state of the absorbent article. This enables rapid water absorption over a wide area of the absorbent member. In addition, water is not easily present on the upper surface of the split body, and therefore, occurrence of rewet can be prevented. This can maintain a good feel of the absorbent article.

In addition, the good bulkiness of the opened body can be maintained in use. Therefore, even when the absorbent article is compressed or absorbs water during use, the excellent rebound resilience of the absorbent article and the shape of the absorbent article can be maintained. This can maintain the fiber gap in which water flows in the opened fiber body. In addition, the opened fiber body has good bulkiness, so that the thickness dimension of the absorbent article can be increased. Therefore, the absorbent article can maintain a good feeling of use before and after water absorption.

The long fibers may be cellulose acetate fibers. With this configuration, the opened body can be configured to be bulky. In addition, the affinity of the opened fiber body with water can be improved. Therefore, moisture can be rapidly absorbed and dispersed in the opened fibers. This can prevent rewet more effectively and improve the feeling of use of the absorbent article.

The content of the binder contained in the opened fiber body may be a value in the range of 0 wt% or more and 10 wt% or less. This can prevent the plurality of long fibers in the opened fiber from being difficult to move relative to each other by the binder. Therefore, the absorbent article can maintain a bulky and soft feel. Further, the touch of the absorbent article can be prevented from being lowered by the adhesive.

The absorbent member may include a pulp sheet and particulates dispersed in the pulp sheet and having water absorption properties. This allows water passing through the fiber-opening body to be quickly absorbed into the respective granular matters dispersed in the pulp sheet. This can prevent, for example, the occurrence of rewet due to local water accumulation in the absorbent member.

The weight of the fiber-opened body in square meters (basis weight) is 80g/m²Above and 100g/m²At a value within the following range, the compression energy WC in a state of being compressed from the natural state to a thickness dimension of 50% may be less than 1.9gfm/cm²A value within the range of (1). Further, the weight of the opened fiber body in square meter is 50g/m²Above and below 80g/m²A value within the range of (c), the compression energy WC in a state of being compressed from a natural state to a thickness dimension of 50% may be less than 1.7gfm/cm²A value within the range of (1). Further, the weight of the opened fiber body in square meter is 20g/m²More than and less than 50g/m²A value within the range of fromThe compression energy WC in a state where the natural state is compressed to a thickness dimension of 50% may be less than 1.3gfm/cm²A value within the range of (1). Further, the weight of the opened fiber body in square meter is less than 20g/m²A value within the range of (c), the compression energy WC in a state of being compressed from a natural state to a thickness dimension of 50% may be less than 1.2gfm/cm²A value within the range of (1).

With each of these configurations, even when the absorbent article is loaded with a load during use, deformation of the opened body can be prevented. Therefore, even in the absorbent article in use, the entangled state of the fibers in the opened fibers and the rich fiber gaps can be maintained. Therefore, the water absorption time for the opened fibers to absorb water can be shortened. Further, the time required for water absorption can be suppressed when the opened fiber is allowed to absorb water again. Further, it is possible to prevent the decrease in the resiliency of the absorbent article in use. This enables the performance of the absorbent article to be maintained even after long-term use.

The absorbent article may further include: a back sheet which is arranged to overlap with the side of the absorbent member opposite to the fiber-opening body and has air permeability; and a top sheet which is arranged to overlap with the fiber opening body on the side opposite to the absorbent member and has liquid permeability. Thus, the fiber-opening body and the absorbent member can be held by the back sheet and the top sheet, and moisture can be efficiently sucked into the fiber-opening body through the top sheet. In addition, it is possible to prevent moisture absorbed by the absorbent member from leaking to the outside through the back sheet.

Effects of the invention

According to the aspects of the present invention, in the absorbent article including the absorbent body having water absorption properties, the absorbent article can maintain a bulky state and a good feeling of use before and after water absorption.

Drawings

Fig. 1 is a sectional view of an absorbent article of the first embodiment.

Fig. 2 is a schematic view of the apparatus for manufacturing an absorbent article according to the first embodiment.

Fig. 3 is a sectional view of the absorbent article of the second embodiment.

FIG. 4 is an enlarged photograph of the opened body of example 21.

FIG. 5 is an enlarged photograph of the opened body of example 22.

FIG. 6 is an enlarged photograph of the opened body of comparative example 6.

FIG. 7 is an enlarged photograph of the opened body of comparative example 7.

Detailed Description

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

(first embodiment)

[ absorbent article ]

Fig. 1 is a sectional view of an absorbent article 1 of the first embodiment. As shown in fig. 1, the absorbent article 1 is entirely configured in a sheet shape. The absorbent article 1 includes a back sheet 2, an absorbent member 3, a split body 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 the following structure: the absorbent member 3 and the split fiber 4 are covered with the backsheet 2 and the top sheet 5 in a superposed state.

The top sheet 5 covers the upper surface of the opening body 4 and allows moisture to permeate therethrough. The top sheet 5 is arranged to overlap the side of the opened fiber body 4 opposite to the absorbent member 3. The top sheet 5 is a porous resin film. The top sheet 5 may be a nonwoven fabric having liquid permeability.

The back sheet 2 has breathability, covers the lower surface of the absorbent member 3, and supports the absorbent member 3 from below. The back sheet 2 is arranged to overlap the absorbent member 3 on the side opposite to the split fiber 4, and prevents the moisture in the absorbent member 3 from leaking to the outside. As an example, the back sheet 2 is a resin film having liquid impermeability.

The absorbent member 3 has water-absorbing properties and is formed in a sheet shape. As an example, the absorbent member 3 of the present embodiment includes a pulp sheet 6 and particulates 7, and the particulates 7 are dispersed in the pulp sheet 6 and have water absorption properties. As an example, the particulates 7 include a Super absorbent resin (SAP). The granular matters 7 are dispersedly disposed in the fiber gaps of the pulp sheet 6 and held by the pulp fibers of the pulp sheet 6. The configuration of the absorbing member 3 is not limited to this.

The fiber opening member 4 is disposed to overlap the absorbent member 3. The fiber opening member 4 includes a plurality of long fibers that are crimped and opened. The split body 4 is formed into a sheet shape. As an example, the opened body 4 is long. The thickness of the fiber opening body 4 can be set as appropriate. The thickness dimension of the fiber opening body 4 may be larger than the thickness dimension of the absorbent member 3, or may be smaller than the thickness dimension of the absorbent member 3, for example. As an example, the long fibers contained in the opened fibers 4 are cellulose acetate fibers. The fibers contained in the opened fiber body 4 may be other fibers such as rayon and synthetic fibers. The total fineness (total denier: TD) and the single-filament fineness (single-filament denier: FD) of the opened fiber body 4 can be set as appropriate.

For example, the thickness of the opened fiber 4 is in the range of 0.6mm to 15.0 mm. Further, the weight per unit area of the split fibers 4 was 100g/m²Values within the following ranges. Furthermore, the area of the opened body 4 in plan view is 100cm²Above and 900cm²Values within the following ranges.

The fiber opening body 4 is opened in a state where a plurality of crimped fibers are entangled with each other. This allows the opened fiber 4 to have a large fiber gap. The void ratio of the opened fiber body 4 is set to a value in the range of 87% or more and less than 100%. The void ratio (%) referred to herein means a volume V based on the opened fiber₁And the total volume V of the fibers in the opened body 4₂According to the formula {100- (V)₂/V₁) X 100. Calculating the volume V based on the ratio M/D of the total weight M of the fibres to the density D of the fibres₂. Furthermore, the volume V can be calculated, for example, based on the projected area of each surface of the open-fiber body 4₁。

The entanglement of the fibers of the opened body 4 with each other is uniform in the entire direction. The plurality of fibers of the opened body 4 are sufficiently entangled with each other. Therefore, the split body 4 is rich in resilience. The tensile strength of the opened fiber 4 in the vertical direction and the width direction per unit volume is substantially the same, for example.

In addition, in the absorbent article 1 of the present embodiment, theThe compression energy WC of the fiber 4 compressed from the natural state to a thickness of 50% is less than 1.9gfm/cm²A value within the range of (1). Further, as for the compression energy WC in the state where the opened fiber body 4 is compressed from the natural state to the thickness dimension of 50%, the weight in square meter of the opened fiber body 4 is 50g/m²Above and below 80g/m²A value in the range of less than 1.7gfm/cm²A value in the range of 20g/m in the square meter weight of the open fiber body 4²More than and less than 50g/m²A value in the range of less than 1.3gfm/cm²A value in the range of less than 20g/m in the square meter weight of the open fiber body 4²A value in the range of less than 1.2gfm/cm²A value within the range of (1).

By setting the value of the compression energy WC of the spreading body 4 in this way, the spreading body 4 can maintain the form of the absorbent article 1 to some extent even when some load is applied during use of the absorbent article 1. Therefore, the performance and the feeling of use of the absorbent article 1 can be stably maintained. Further, as described above, by adjusting the value of the compression energy WC in accordance with the square meter weight of the opened body 4, it is possible to provide appropriate and good resiliency (elasticity) to the opened body 4 having different square meter weights and to maintain the form in use.

The fibers of the opened body 4 are strongly entangled with each other. Therefore, in the opened fiber body 4, an adhesive for bonding the fibers to each other is substantially not required. In the present embodiment, the content of the binder contained in the open fibers 4 is a value in the range of 0 wt% to 10 wt%. That is, the open fiber 4 of the absorbent article 1 contains no binder or only a small amount of binder. Examples of the adhesive include known adhesives such as triacetin.

As described above, in the absorbent article 1, the opened body 4 includes a plurality of long fibers that are crimped and opened, and the void ratio thereof is a value in the range of 87% or more and less than 100%. In this way, the void ratio of the opened fibers 4 is a relatively high value, and therefore the opened fibers 4 can be configured to be bulky. In addition, a large number of fiber gaps can be formed inside the opened fiber body 4. Therefore, even after the absorbent article 1 absorbs water, the moisture can be passed through the fiber gaps of the opened fibers 4 while being diffused, while maintaining the bulkiness of the absorbent article 1. This enables water to be quickly absorbed over a wide area of the absorbent member 3. In addition, water is less likely to be present on the upper surface of the split body 4, and therefore, occurrence of rewet can be prevented. This can maintain a good feel of the absorbent article 1.

In addition, the good bulkiness of the opened body 4 can be maintained in use. Therefore, even when the absorbent article 1 is compressed or absorbs water during use, the excellent rebound resilience of the absorbent article 1 and the form of the absorbent article 1 can be maintained. This can maintain the fiber gap through which water flows in the opened fiber 4. Further, the opened fiber 4 has good bulkiness, so that the thickness dimension of the absorbent article 1 can be increased. Therefore, the favorable use feeling of the absorbent article 1 can be maintained before and after water absorption.

In the present embodiment, the long fibers of the opened fiber body 4 are cellulose acetate fibers. With this configuration, the opened fibers 4 can be configured to be bulky. In addition, the affinity of the fibrillics 4 with water can be improved. Therefore, moisture can be rapidly absorbed and dispersed in the opened fibers 4. This can prevent rewet more effectively and improve the feeling of use of the absorbent article 1.

In the absorbent article 1, the content of the binder contained in the open fibers 4 is a value in the range of 0 wt% to 10 wt%. This can prevent the plurality of long fibers in the fiber opening body 4 from being difficult to move relative to each other by the binder, and can maintain the bulky and soft feel of the absorbent article 1. Further, the touch of the absorbent article 1 can be prevented from being lowered by the adhesive.

The absorbent member 3 has a pulp sheet 6 and particulates 7, and the particulates 7 are dispersed in the pulp sheet 6 and have water absorption properties. This allows moisture passing through the fiber-opening body 4 to be quickly absorbed into the respective granular materials 7 dispersed in the pulp sheet 6. This can prevent, for example, the occurrence of rewet due to local water accumulation in the absorbent member 3.

Furthermore, the split body 4 is compressed from the natural state to a thickness dimension of 5Compression energy WC in the 0% state is less than 1.9gfm/cm²A value within the range of (1). With this configuration, even when the absorbent article 1 is loaded with a load during use, the form of the split bodies 4 can be prevented from being deformed. Therefore, in the absorbent article 1 during use, the entangled state of the fibers in the fiber opening bodies 4 and a large amount of fiber gaps can be maintained. Therefore, the water absorption time of the opened fiber body 4 for absorbing water can be shortened. Further, the time required for water absorption can be suppressed when the opened fibers 4 absorb water repeatedly. Further, it is also possible to prevent the decrease in the resiliency of the absorbent article 1 in use. This maintains the performance of the absorbent article 1 even after long-term use.

The absorbent article 1 further includes: a back sheet 2 that is arranged to overlap the absorbent member 3 on the side opposite to the split fiber 4 and has air permeability; and a top sheet 5 disposed to overlap the side of the opened fiber body 4 opposite to the absorbent member 3 and having liquid permeability. This allows the opened fiber body 4 and the absorbent member 3 to be held by the back sheet 2 and the top sheet 5, and allows moisture to be efficiently sucked into the opened fiber body 4 through the top sheet 5. Further, it is also possible to prevent moisture absorbed by the absorbent member 3 from leaking to the outside through the back sheet 2. In addition, a member having liquid permeability may be separately provided at least either between the top sheet 5 and the spread body 4 or between the spread body 4 and the absorbent member 3.

[ absorbent article manufacturing apparatus ]

Fig. 2 is a schematic view of an absorbent article manufacturing apparatus 20 (hereinafter, simply referred to as a manufacturing apparatus 20) according to the first embodiment. As shown in fig. 2, a packaging container 60 is disposed in the vicinity of the manufacturing apparatus 20. In the packaging container 60, a tow band 61 including a plurality of long fibers that are crimped is folded and compressed into a tissue shape, and then packaged. The packaging 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 tow band 61 is conveyed in the predetermined conveying direction P while being kept horizontal in the width direction.

The manufacturing apparatus 20 includes a first manufacturing unit 22 and a second manufacturing unit 23. The first manufacturing section 22 includes a first spreader B1, a guide 25, a second spreader B2, a first opening roller pair 26, a second opening roller pair 27, an air opening device 28, and a conveying roller pair 29.

The tenter devices B1 and B2 widen the tow band 61 in the width direction. The guide 25 guides the tow band 61 passing through the first tenter B1 toward the second tenter B2. The pair of opening

rollers

26 and 27 further opens the tow band 61 passing through the second tenter B2 on the upstream side of the air opening device 28. The second opening roller pair 27 is disposed downstream of the first opening roller pair 26. The first opening roller pair 26 has a pair of

rollers

30 and 31. The second opening roller pair 27 has a pair of

rollers

32 and 33. The

rollers

32, 33 rotate at a peripheral speed faster than that of the

rollers

30, 31.

The tow band 61 passing through the second tenter B2 is inserted between the pair of

rollers

30, 31 and between the pair of

rollers

32, 33. The tow band 61 is in contact with the peripheral surfaces of the rollers 30 to 33, and is thereby tensioned in the conveyance direction P to be fluffy opened.

The air opening device 28 opens the tow band 61 passing through the second pair of opening rollers 27. The gas opening device 28 includes a main body 50, an opening molding section 51, and a retention section 52. The main body 50 mixes the tow band 61 with gas G (air, as an example) supplied from the outside. The fiber-opening forming section 51 opens and forms the tow band 61 passing through the main body 50 by the gas G. The retention section 52 includes a plurality of elongated members 53 extending in the conveyance direction P and arranged in the circumferential direction of the tow band 61. The retention section 52 temporarily retains the tow band 61 passed through the opening and molding section 51 to adjust the density and bulkiness of the tow band 61. The inlet and outlet of the body portion 50 are circular. The inlet of the spreading and molding section 51 is circular, and the outlet is flat with the width direction of the tow band 61 larger than the vertical direction.

The tow band 61 introduced into the gas opening device 28 is transported in the transport direction P while being mixed with the gas G introduced from the outside in the direction perpendicular to the transport direction P in the entire internal space 50a provided in the main body 50, and is discharged from the main body 50. Thereby, the tow band 61 expands in volume and decreases in density. The tow band 61 passed through the main body 50 is passed through an opening chamber 51a having a flat cross section of a flow path provided in the opening forming section 51, and is opened and formed while being expanded in diameter in the width direction. Thereby, the tow band 61 is fluffy and uniformly opened as compared with, for example, the case of passing through an opening device whose widthwise dimension is fixed. Further, entanglement of the long fibers in the tow band 61 is uniform in the whole direction of the tow band 61, and the degree of entanglement is increased.

The tow band 61 passed through the opening and molding section 51 is temporarily retained in the retention chamber 52a provided in the retention section 52, and the density and bulkiness can be adjusted while maintaining the cross-sectional shape perpendicular to the conveyance direction P. For details of the gas spreading device 28, for example, refer to patent No. 5526109.

The conveying roller pair 29 includes conveying

rollers

34 and 35 arranged with their circumferential surfaces facing each other. The tow band 61 passed through the air opening device 28 is inserted between the conveying

rollers

34 and 35, and is pressed in the thickness direction by the conveying

rollers

34 and 35. This enables the production of the sheet-like opened fiber 4. The opened fiber 4 is conveyed to the second manufacturing section 23 while being guided by the guide roller 36.

The second manufacturing unit 23 manufactures the absorbent article 1 by placing the absorbent member 3 and the split fiber 4 in a superposed manner and covering them with the top sheet 5 and the back sheet 2. The second manufacturing section 23 includes a roll R1 for winding the back sheet 2, a roll R2 for winding the top sheet 5, and a roll R3 for winding the pulp sheet 6. The second manufacturing section 23 includes

guide rollers

37 and 38, a first feeding device 40, a second feeding device 41, a conveying roller pair 42, a sheet forming roller pair 43, and a sheet conveying device 44.

The first supply device 40 supplies the particulate matter 7 to the pulp sheet 6 so that the particulate matter 7 is spread inside the belt-like pulp sheet 6 which is drawn out from the roll R3 and conveyed on the conveyance line L. This enables the belt-like absorbent member 3 to be formed. The belt-like absorbent member 3 is supported from below by the belt-like back sheet 2 fed from the roller R1 and conveyed on the conveyor line L, and is overlapped with the opened fiber 4 from above. The laminated body composed of the back sheet 2, the absorbent member 3, and the fiber opening body 4 is passed between the

rollers

45, 46 of the conveying roller pair 42 and conveyed to the downstream side.

Next, the stacked body is overlapped with the top sheet 5 fed from the roller R2, guided by the guide roller 38, and conveyed in the conveyance line L. The surface of the top sheet 5 on the back sheet 2 side is coated with an adhesive in advance by the second supply device 41. The back sheet 2, the absorbent member 3, the opened fiber body 4, and the top sheet 5 are passed between the rollers 47, 48 of the sheet forming roller pair 43 to be integrally formed into a sheet shape. Further, the top sheet 5 and the back sheet 2 pass through the sheet feeder 44 to be bonded. Then, the absorbent article 1 is obtained by cutting these components 2 to 5 into a predetermined size.

As described above, the method for manufacturing the absorbent article 1 of the present embodiment includes the steps of: a split-fiber forming step of forming a split fiber 4 by splitting and molding the tow band 61; an absorbent member forming step of forming the absorbent member 3; and a bonding step of bonding the back sheet 2 and the top sheet 5 in a state where the absorbent member 3 and the split fiber 4 are arranged to overlap each other between the back sheet 2 and the top sheet 5. Through these steps, an absorbent article 1 having a bulky open fiber 4 having a void ratio in the range of 87% or more and less than 100% can be obtained.

Here, in the fiber opening forming step of the present embodiment, a tow band 61 composed of a plurality of crimped cellulose acetate fibers is used. In the fiber-opening forming step, after the tow band 61 is mixed with the gas G in the entire direction perpendicular to the conveying direction P of the conveyed tow band 61, the tow band 61 is opened and formed by the gas G in the opening chamber 51a having a width dimension larger than the vertical dimension and increasing toward the downstream side in the conveying direction P. At this time, the tow band 61 is pressed against the inner circumferential surface of the opening chamber 51 a. Further, in the absorbent member forming step, the absorbent member 3 is formed by adding the particulate matter 7 having water absorption property into the pulp sheet 6. Hereinafter, the second embodiment will be described centering on differences from the first embodiment.

(second embodiment)

Fig. 3 is a sectional view of the absorbent article 11 of the second embodiment. The absorbent member 8 of the absorbent article 11 has a support sheet 9 made of nonwoven fabric, and the particulate matter 7 fixed to one surface (here, the upper surface) of the support sheet 9. The particulate matter 7 is fixed to the support sheet 9 by an adhesive (for example, a hot-melt adhesive). Even in the absorbent article 11 having such a configuration, the same effects as those of the absorbent article 1 can be expected. Further, since the particulate matter 7 does not move during use, the absorbent property of the absorbent article 11 can be prevented from being biased, and the absorbent article 11 can be used stably. The structure for fixing the particulate matter 7 to the support sheet 9 may be a structure not using an adhesive.

(confirmation test)

Next, the confirmation test will be described, but the present invention is not limited to the following examples.

[ appearance/touch evaluation test ]

Using the absorbent article manufacturing apparatus 20 of the first embodiment, the following opened fiber body 4 was manufactured as example 1: comprising cellulose acetate fibers having a single-fiber fineness of 6 and having a weight in square meters of 50g/m²The porosity was set to 99%. In comparative example 1, an absorbent article manufacturing apparatus having the same configuration as the absorbent article manufacturing apparatus 20 was used to manufacture a spread having a void ratio of 85% except that a thickening apparatus for thickening a spun lace band by filling air only in the vertical direction perpendicular to the conveyance direction P was used instead of the air spreading apparatus 28. The bulkiness was evaluated visually and the feel was evaluated by hand for the obtained opened fibers of example 1 and comparative example 1. As a result, it was found that: example 1 had a fluffy and soft touch compared to comparative example 1.

[ measurement of Water absorption time under load ]

Next, the test was performed for example 1 and comparative example 1 in the following procedure. The opened body of example 1 or comparative example 1 was disposed between an absorbent core (corresponding to an absorbent member) and a topsheet (corresponding to a topsheet) of a commercially available absorbent article (baby diaper made by da wang paper). The plate with the opening formed was placed on the surface sheet in an overlapping manner, and a weight (2kg) was placed on the plate, thereby applying a fixed load to the split fibers of example 1 and comparative example 1.

In this way, 80cc of physiological saline was dropped to the split fiber through the opening of the plate in a state where the split fiber was loaded with a load. Then, the time from the start of the dropping to the completion of the inhalation was measured as the first water absorption time. After 5 minutes of dropping, the plate and the weight were removed, the filter paper was placed on the surface sheet, and the weight (3.5kg) was placed on the filter paper to remove excess water. After 3 minutes after the filter paper and the weight were placed, the filter paper and the weight were detached. After 2 minutes, a plate and a weight (2kg) were attached, and the second water absorption time was measured by dropping in the same manner as the first. According to this test, it can be evaluated that the water absorption performance is higher as the water absorption time is shorter (in other words, the water absorption speed is higher). The results of the 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 shortened in both the first water absorption and the second water absorption as compared with the water absorption time of comparative example 1. For this reason, it is considered that: the open fibers 4 of example 1 had a higher porosity than that of comparative example 1, and therefore, the physiological saline solution that entered the fiber gaps was allowed to flow rapidly and be absorbed into the absorbent core. Further, it can be considered that: in the open fiber body 4 of example 1, since the fibers are entangled with each other more strongly than in comparative example 1, the fiber gap can be maintained stably even if water absorption is repeated. Further, by this test, it is considered that: in the absorbent article 1 using the opened fibers 4 of example 1, the opened fibers 4 can absorb moisture quickly, and therefore, the moisture is less likely to leak during use.

[ void ratio measurement test ]

The following opened fibers 4 were produced as examples 2 to 16: the dimensions in plan view were fixed (38 cm. times.11 cm) and the fiber density was fixed (1.32 g/cm)³) To make the volume V of the split fiber body₁Total volume of fiber V₂Thickness dimension and square meter weight. In examples 2 to 16, the thickness of the split fiber 4 was changed within a range of 0.6mm to 15mm (here, the change was 0.6mm, 5mm, or 15 mm), and the square meter weight was adjustedThe amount is 20g/m²Above and 100g/m²And may be varied within the following ranges. Further, the following opened fibers were produced as comparative examples 2 to 4: the same size in plan view as in examples 2 to 16, i.e., the volume V of the opened fiber₁Smaller than in examples 2 to 16. The void ratios of examples 2 to 16 and comparative examples 2 to 4 were adjusted. The measurement results are shown in tables 2 to 5.

[ Table 2]

	Example 2	Example 3	Example 4	Example 5	Example 6
						Length (cm)	38	38	38	38	38
Width (cm)	11	11	11	11	11
						Thickness (cm)	1.5	1.5	1.5	1.5	1.5
Weight in square meter (g/m)²)	20.0	40.0	60.0	80.0	100.0
						Weight of fiber (g)	0.836	1.672	2.508	3.344	4.18
Fiber Density (g/cm)³)	1.32	1.32	1.32	1.32	1.32
						Volume (cm) of the split³)	627	627	627	627	627
Fiber volume (cm)³)	0.63	1.27	1.90	2.53	3.17
						Void fraction under no load (%)	Roughly 100	Roughly 100	Roughly 100	Roughly 100	99

[ Table 3]

	Example 7	Example 8	Example 9	Example 10	Example 11
						Length (cm)	38	38	38	38	38
Width (cm)	11	11	11	11	11
						Thickness (cm)	0.5	0.5	0.5	0.5	0.5
Weight in square meter (g/m)²)	20.0	40.0	50.0	60.0	100.0
						Weight of fiber (g)	0.836	1.672	2.09	2.508	4.18
Fiber Density (g/cm)³)	1.32	1.32	1.32	1.32	1.32
						Volume (cm) of the split³)	209	209	209	209	209
Fiber volume (cm)³)	0.63	1.27	1.58	1.90	3.17
						Void fraction under no load (%)	Roughly 100	99	99	99	98

[ Table 4]

[ Table 5]

	Comparative example 2	Comparative example 3	Comparative example 4	Comparative example 5
					Length (cm)	38	38	38	38
Width (cm)	11	11	11	11
					Thickness (cm)	0.025	0.01	0.04	0.05
Weight in square meter (g/m)²)	50.0	20.0	80.0	100.0
					Weight of fiber (g)	2.09	0.836	3.344	4.18
Fiber Density (g/cm)³)	1.32	1.32	1.32	1.32
					Volume (cm) of the split³)	10	4	17	21
Fiber volume (cm)³)	1.58	0.63	2.53	3.17
					Void fraction under no load (%)	85	85	85	85

As shown in tables 2 to 5, it can be seen that: the void ratios of examples 2 to 16 were values in the range of 87% or more and less than 100%, and the void ratios were larger than those of comparative examples 2 to 4. In contrast, the void ratios of comparative examples 2 to 4 were maintained at 85%. From this, it can be seen that: examples 2-16 had relatively bulky and high void fractions. Further, as shown in the results, it was found that: e.g. by adjusting the splitting bodyThickness dimension and volume V of split fiber₁The void ratio of the fiber-opening body can be adjusted. Further, as shown in examples 2 to 16, it can be seen that: when the thickness of the opened fiber body 4 is set to be in the range of 0.6mm to 15mm, the weight of the fiber body in square meter is set to be 20g/m²Above and 100g/m²With the values in the following ranges, the open fiber 4 having the target void ratio can be easily and stably produced.

[ compression test ]

Using the absorbent article manufacturing apparatus 20 of the first embodiment, the following fibers 4 (porosity 99%) were manufactured as examples 17 to 24: is composed of cellulose acetate fiber with a filament number of 3 or 6, and the weight of the square meter is 20g/m²、50g/m²、80g/m²Or 100g/m². In examples 17 to 24, compression tests were carried out by the KES (Kawabata Evaluation System: Chuan-end Evaluation System) method, and compression energies WC were measured.

Specifically, a commercially available compression tester ("KES-G5" made by Garcinia technology, Inc.) was used, and the measurement conditions were set to a compression rate of 0.01cm/sec and a compression area of 2cm²A sensitivity (SENS) of 2 and an upper limit load of 50gf/cm². Then, the opened body was pressed by a nonwoven fabric sheet, and a load was applied to the entire opened body, and the opened body was fixed to a base in a state of being compressed to 50% of the initial thickness dimension (thickness dimension in the natural state), and the compression energy WC was measured. Can be evaluated as: the larger the value of the compression energy WC is, the softer the compression energy WC is, and conversely, the smaller the value is, the more elastic the compression energy WC is. The measurement results are shown in table 6.

[ Table 6]

	Weight in square meter (g/m)²)	FD	Thickness at measurement (mm)	WC(gfcm/cm²)	Void fraction under no load (%)
						Example 17	100	3	3.4	1.78	99
Example 18	100	6	3.4	1.55	99
						Example 19	80	3	3.0	1.67	99
Example 20	80	6	2.9	1.48	99
						Practice ofExample 21	50	3	2.6	1.28	99
Example 22	50	6	2.4	1.18	99
						Example 23	20	3	1.9	1.14	99
Example 24	20	6	1.8	1.10	99

As shown in table 6, it was confirmed that: the compression energy of examples 17 to 24 was very small, and they had good elasticity. From this, it can be considered that: examples 17 to 24 were flexible until a fixed load was applied, and were not easily deformed after the fixed load was applied. Further, it can be considered that: the absorbent article 1 using the split bodies 4 of examples 17 to 24 had good resiliency (elasticity), and was able to maintain a good shape even under a load during use, and was not easily deformed.

As the reason for obtaining such a result, it is considered that: in examples 17 to 24, when the split body 4 was produced, the tow band 61 was split by the gas G, so that entanglement of the fibers of the split body 4 was relatively strong, and even if some load was applied to the split body 4, the internal structure of the split body 4 was not easily changed, and the shape of the split body 4 could be maintained.

Further, from the results of the compression test, it is considered that: according to the absorbent article 1 using the opened fibers 4 of examples 17 to 24, the feeling of excellent flexibility can be exhibited in a state where no compression load is applied (initial state). Further, it can be considered that: the spring can exhibit good spring performance while maintaining its shape in a state where a compressive load is applied (in a use state). From this, it can be considered that: in the absorbent article 1, the fluff-forming bodies 4 are prevented from being compressed excessively during use, and liquid leakage is prevented, and water absorption properties can be exhibited stably.

Further, according to another compression test performed by the inventors, it was confirmed that: the weight of the opened fiber body 4 in square meter is 80g/m²Above and 100g/m²At a value within the range below, the compression energy WC in a state of being compressed from the natural state to a thickness dimension of 50% is less than 1.9gfm/cm²A value within the range of (1). Further, it can be confirmed that: the weight of the opened fiber body 4 in square meter is 50g/m²Above and below 80g/m²A value in the range of less than 1.7gfm/cm, a compression energy WC in a state of being compressed from a natural state to a thickness dimension of 50%²A value within the range of (1). Further, it can be confirmed that: the weight of the opened fiber body 4 in square meter is 20g/m²More than and less than 50g/m²A value in the range of less than 1.3gfm/cm, a compression energy WC in a state of being compressed from a natural state to a thickness dimension of 50%²A value within the range of (1).

From the results of such a compression test and the like, it was confirmed that: the value of the compression energy varies depending on FD, square meter weight, void ratio, and the like. Therefore, as a method of setting the compression energy of the opened fibers 4 as a target value, for example, a method of changing at least one of items such as FD, square meter weight, and void ratio can be considered.

Here, fig. 4 is an enlarged photograph of the opened fiber 4 of example 21. Fig. 5 is an enlarged photograph of the open fiber 4 of example 22. FIG. 6 is an enlarged photograph of the opened body of comparative example 6. FIG. 7 is an enlarged photograph of the opened body of comparative example 7. Comparative example 6 is a spread body having a void ratio of 85% and produced by using an absorbent article production apparatus having the same configuration as the absorbent article production apparatus 20, except that the gas spreading device 28 was not used, which corresponds to example 21. Comparative example 7 is a spread body having a void ratio of 85% and produced by using an absorbent article production apparatus having the same configuration as that of the absorbent article production apparatus 20, except that the gas spreading device 28 was not used, and which corresponds to example 22. FIGS. 4 to 7 show photographs of the opened fiber taken at 35-fold magnification using a digital microscope "RH-2000" manufactured by HIROX.

As shown in FIGS. 4 to 7, it was confirmed that: compared with the opened fibers of comparative examples 6 and 7, the fiber gaps and entanglement of the fibers of the opened fibers 4 of examples 21 and 22 were uniformly formed in the entire direction. In comparative examples 6 and 7, as shown in fig. 6 and 7, regions with relatively thin fibers were observed, and in examples 21 and 22, as shown in fig. 4 and 5, such regions were not observed. From this result, it can be considered that: examples 21 and 22 had uniform characteristics as a whole as compared with comparative examples 6 and 7.

The present invention is not limited to the embodiments and examples, and modifications, additions, or deletions can be made to the structure and method without departing from the scope of the invention. Various known additives such as a colorant may be added to the open fiber 4.

Industrial applicability of the invention

As described above, according to the present invention, an absorbent article including an absorbent body having water absorption properties has an excellent effect of maintaining a bulky and excellent feeling in use before and after water absorption. Therefore, the present invention is useful for a wide range of applications as an absorbent article that can exhibit the effect.

Description of the reference numerals

1. 11 absorbent article

2 Back sheet

3 absorbent member

4-split fiber body

5 Top sheet

6 paper pulp sheet

7 granular material

Claims

1. An absorbent article provided with:

a sheet-like absorbent member for absorbing moisture, and

a fiber opening body arranged to overlap with the absorbent member and including a plurality of crimped and opened long fibers,

the void ratio of the opened fiber body is a value in the range of 87% or more and less than 100%.

2. The absorbent article of claim 1,

the long fibers are cellulose acetate fibers.

3. The absorbent article according to claim 1 or 2, wherein,

the content of the binder contained in the opened fiber body is a value within a range of 0 wt% or more and 10 wt% or less.

4. The absorbent article according to any one of claims 1 to 3, wherein,

the absorbent member has a pulp sheet and particulates dispersed in the pulp sheet and having water absorption properties.

5. The absorbent article according to any one of claims 1 to 4, wherein,

the weight of the fiber-opening body in square meter is 80g/m²Above and 100g/m²At a value within the range below, the compression energy WC in a state of being compressed from the natural state to a thickness dimension of 50% is less than 1.9gfm/cm²A value within the range of (1).

6. The absorbent article according to any one of claims 1 to 5, wherein,

the weight of the fiber-opening body in square meter is 50g/m²Above and below 80g/m²A value in the range of less than 1.7gfm/cm, a compression energy WC in a state of being compressed from a natural state to a thickness dimension of 50%²A value within the range of (1).

7. The absorbent article according to any one of claims 1 to 6, wherein,

the weight of the fiber-opening body in square meter is 20g/m²More than and less than 50g/m²A value in the range of less than 1.3gfm/cm, a compression energy WC in a state of being compressed from a natural state to a thickness dimension of 50%²A value within the range of (1).

8. The absorbent article according to any one of claims 1 to 7, wherein,

the weight of the fiber-opening body in square meter is less than 20g/m²A value in the range of less than 1.2gfm/cm, a compression energy WC in a state of being compressed from a natural state to a thickness dimension of 50%²A value within the range of (1).

9. The absorbent article according to any one of claims 1 to 8, wherein,

the absorbent article further includes:

a back sheet which is arranged to overlap with the side of the absorbent member opposite to the fiber-opening body and has air permeability; and

a top sheet disposed to overlap with the fiber opening body on a side opposite to the absorbent member, and having liquid permeability.