JP5094173B2 - Absorbent article and manufacturing method thereof - Google Patents

Description

  The present invention relates to a fiber sheet, a method for producing the same, and an absorbent article using the same.

Conventionally, in an absorbent article such as a sanitary napkin, an absorbent layer having a medium-high structure is known in order to improve fit to a wearer's body (see, for example, Patent Document 1 below). As an absorption layer that forms a medium-high structure, it has both a soft and soft cushioning property that fits the shape of the wearer's body and an absorption property that quickly absorbs excretions excreted from the wearer. Is desired.
Moreover, it has the 1st nonwoven fabric and the 2nd nonwoven fabric which were bitten between the uneven | corrugated rolls and formed the unevenness | corrugation as a surface sheet for absorbent articles, and it is short between the convex part of a 1st nonwoven fabric, and a 2nd nonwoven fabric. A surface sheet filled with fibers is known (see Patent Document 2).

JP 2005-152250 A JP 2006-115974 A

In the absorbent article described in Patent Document 1, a medium-high structure is formed by disposing a sheet-like material made of a foam in the absorbent layer. Therefore, in the absorbent article of patent document 1, although cushioning properties are excellent, the absorptivity is not excellent.
In addition, the surface sheet of Patent Document 2 is such that when the first nonwoven fabric and the second nonwoven fabric are heat-sealed, short fibers are likely to enter between the two nonwoven fabrics, the heat-sealed portion is likely to be hard, and the flexibility of the sheet as a whole. Slightly inferior.

Accordingly, an object of the present invention is to provide a fiber sheet that is excellent in cushioning properties and flexibility as a whole sheet, and is preferably used to form a medium-high structure excellent in cushioning properties, for example.
Moreover, the objective of this invention is providing the manufacturing method of the fiber sheet which can manufacture such a fiber sheet efficiently, and an absorbent article provided with this fiber sheet and excellent in cushioning property and a softness | flexibility. is there.

  The present invention has a stretchable first fiber layer and a second fiber layer, wherein the first fiber layer and the second fiber layer are partially joined to form a joint, and the second fiber In the layer, a portion other than the joining portion forms a protruding portion that is convex toward the side opposite to the first fiber layer side, the first fiber layer includes crimped fibers, and the stretchability is mainly A fiber sheet derived from the stretchability of the crimped fiber, wherein the degree of crimp of the crimped fiber in the vicinity of the joint is greater than the degree of crimp of the crimped fiber in a portion far from the joint The above object is achieved by providing the above.

  Further, in the method for manufacturing the fiber sheet, a large number of joint portions are formed by subjecting a laminate of the first fiber assembly and the second fiber assembly including latent crimpable fibers to heat embossing. Forming a spiral crimp on the latent crimpable fiber in the vicinity of the joint, and subjecting the laminate after forming the joint to hot air treatment at a temperature lower than the temperature of the hot embossing. The object is achieved by providing a method for producing a fiber sheet, comprising the step of shrinking the laminate in both longitudinal and lateral directions.

  In addition, the present invention provides an absorbent article that includes the fiber sheet, and the fiber sheet is disposed in a state where the first fiber layer side is directed to the skin contact surface side.

The object of the present invention is excellent in cushioning properties and flexibility of the sheet as a whole, and is preferably used, for example, to form a medium-high structure excellent in cushioning properties.
Moreover, according to the manufacturing method of the fiber sheet of this invention, such a fiber sheet can be manufactured efficiently.
Moreover, the absorbent article of this invention is excellent in cushioning property and a softness | flexibility.

Hereinafter, the fiber sheet of the present invention and an absorbent article using the same will be described based on a preferred embodiment thereof with reference to the drawings.
FIG. 1 is a view showing a sanitary napkin which is an embodiment of the absorbent article of the present invention.
The sanitary napkin 1 of the present embodiment has a vertically long shape like a normal sanitary napkin, and as shown in FIG. 1, a liquid-permeable surface sheet 2, liquid-impermeable or liquid-impermeable. The liquid-retaining absorbent layer 4 interposed between the sheet 2 and the sheets 2 and 3 is provided.

In the sanitary napkin 1 of the present embodiment, a middle-high portion 6 that protrudes toward the wearer's skin side is formed at a portion that is opposed to the liquid excretion portion of the wearer when worn as shown in FIG. ing. The protrusion 6 is formed at the center of the sanitary napkin 1 in the width direction, and has a length extending from the liquid excretion part of the wearer to a little behind the anus.
As shown in FIG. 1, the absorption layer 4 has a structure in which an upper absorption layer 41 and a lower absorption layer 42 are laminated. The upper absorption layer 41 is smaller than the lower absorption layer 42 and has a length of a napkin. The length in any of the direction and the width direction is smaller than that of the upper absorbent layer 41. In the absorption layer 4, the portion where the upper absorption layer 41 is laminated on the lower absorption layer 42 forms the above-described middle-high portion 6.
The middle-high part 6 in the napkin 1 of this embodiment fits a wearer's liquid excretion part flexibly, and has a function which absorbs the liquid excreted from this liquid excretion part quickly.

As a material for forming the top sheet 2, the back sheet 3, the upper absorbent layer 41, and the lower absorbent layer 42 in the napkin 1 of the present embodiment, various materials conventionally used in absorbent articles such as sanitary napkins are not particularly limited. Can be used.
As the surface sheet 2, for example, liquid permeable sheets such as various nonwoven fabrics and perforated films subjected to a hydrophilic treatment can be used. As the back sheet 3, for example, a liquid-impermeable or water-repellent sheet such as a thermoplastic resin film or a laminate of the film and a nonwoven fabric can be used, and a water-permeable sheet can also be used. . As the upper absorbent layer 41 and the lower absorbent layer 42, hydrophilic layers such as a laminated fiber layer obtained by depositing pulp fibers, a mixed laminated fiber layer obtained by depositing pulp and a superabsorbent polymer, and pulp fibers. What consists of the nonwoven fabric which uses a fiber as a raw material can be used. The upper absorbent layer 41 is preferably a softer layer than the lower absorbent layer 42.

In the sanitary napkin 1 described above, a fiber sheet 5 that is an embodiment of the fiber sheet of the present invention is disposed between the top sheet 2 and the upper absorbent layer 41.
The fiber sheet 5 which is this embodiment has the 1st fiber layer 51 and the 2nd fiber layer 52 which have elasticity, as shown in FIG.2 and FIG.3, and the 1st fiber layer 51 and the 2nd fiber layer 52 are partially joined to form a large number of joints 53.
The joining portion 53 in the present embodiment is formed by pressurizing and heating the first fiber layer 51 and the second fiber layer 52 integrally, and the first fiber layer 51 and the second fiber in the joining portion 53 are formed. The layer 52 is integrated by melting and solidifying constituent fibers of the first fiber layer 51 and / or constituent fibers of the second fiber layer 52.

As shown in FIG. 3, in the second fiber layer 52, a portion other than the joining portion 53 forms a protruding portion 54 that protrudes toward the side opposite to the first fiber layer 51 side.
As shown in FIG. 2, a large number of joining portions 53 in the present embodiment are formed in a dispersed state in the planar direction of the fiber sheet 5 (direction perpendicular to the thickness direction of the fiber sheet). More specifically, as shown in FIG. 2, a large number of joint portions 53 are formed in a rectangular region 56 surrounded by twelve joint portions 53 in the MD direction of the fiber sheet 5 (machine direction at the time of manufacture, It is formed so as to be continuously formed in both directions of the fiber orientation direction and the CD direction (the direction orthogonal to the machine direction at the time of manufacture, the same as the orthogonal direction of the fiber orientation direction).
A portion of the second fiber layer 52 located in the region 56 in a plan view of the fiber sheet 5 protrudes in a cross-sectional arch shape (see FIG. 3) toward the upper absorbent layer 41, thereby forming the protrusion 54. is doing. On the other hand, the periphery of each protrusion 54 when the fiber sheet 5 is viewed from the second fiber layer 52 side is a recess 55, and the joint 53 is intermittently disposed at the bottom of the recess 55. .

The first fiber layer 51 has elasticity. This stretchability is mainly derived from the stretchability of the crimped fibers contained in the first fiber layer 51.
More specifically, the first fiber layer 51 includes a coiled fiber formed by crimping the latent crimpable fiber in a spiral shape, and is configured to include the coiled fiber. It has elasticity in both the direction and the CD direction. More specifically, it has elasticity in all directions perpendicular to the thickness direction. When the first fiber layer 51 is pulled in the plane direction, the coiled fiber expands, and when the first fiber layer 51 is released, the coiled fiber contracts to return to the original state, and the first fiber layer 51 as a whole contracts along with the contraction. .

In the fiber sheet 5 of the present embodiment, when a force for compressing the fiber sheet 5 in the thickness direction is applied, the protruding portion 54 is compressed in the height direction, the height decreases, and the configuration of the second fiber layer 52 By the fibers, a force is applied to the first fiber layer 51 located around the protruding portion 54 so as to push and spread the first fiber layer 51 in the plane direction. Thereby, the part located in the said area | region 56 in the 1st fiber layer 51 will be in the state extended | stretched in the plane direction.
On the other hand, when the force to compress the fiber sheet 5 in the thickness direction is removed, the stretched first fiber layer 51 contracts, and the contracting force is transmitted to the constituent fibers of the second fiber layer 52, It acts as a force that restores the constituent fibers to a curved state before compression. The recovery force of the protruding portion 54 due to the contraction force of the first fiber layer 51 is combined with the bulk recovery force from the compressed state of the fiber itself constituting the protruding portion 54, so that the protruding portion 54 is It almost recovers to the protruding state before compression.
By such an effect | action, the fiber sheet 5 of this embodiment shows the outstanding cushioning property. Such actions and effects are more reliably exhibited when the cross-sectional shape of the protrusion 54 is arched as in the present embodiment.

  Further, as shown in FIGS. 2 and 3, the first fiber layer 51 of the fiber sheet 5 of the present embodiment has a degree of crimping of the crimped fibers in the vicinity 57 of the joint portion 53 far from the joint portion 53. It is larger than the degree of crimp of the crimped fiber in the portion 58. Specifically, the number of turns per coiled length of the coiled fiber generated by crimping the latent crimpable fiber in a spiral shape is such that the coiled fiber in the vicinity 57 of the bonded portion 53 is the bonded portion 53. It is more than the coiled fiber in the portion 58 far from the coil.

According to the fiber sheet 5 of this embodiment, since it has such a configuration, it has excellent cushioning properties and also has good flexibility (particularly flexibility) as the entire sheet.
In particular, since the degree of crimping of the fibers is different between the vicinity 57 and the distant portion 58 of the joint portion 53 as described above, the following remarkable effects are manifested in cushioning properties and absorbability.
Due to the particularly large crimp of the crimped fibers in the vicinity 57 of the joint portion 53 (that is, the shrinkage of the first fiber layer 51), the arch-like standing of the protruding portion 54 is improved, and the elastic recovery after compression is also excellent. .

Further, due to the difference in the degree of crimp of the crimped fibers, the capillary force in the vicinity 57 of the joint portion 53 is particularly increased. As a result, the liquid absorbed in the first fiber layer 51 is concentrated in the vicinity 57 of the joint portion, and the dryness of the entire sheet is improved.
In particular, the first fiber layer 51 is thicker at the far end 58 than the joint portion 53 and its vicinity 57, and mainly contacts the topsheet 2 at the far 58 portion. While the liquid absorbed in the layer 51 is concentrated in the vicinity 57 of the joint portion 53, the liquid remaining in the distant 58 portion is reduced, so that the liquid return to the top sheet 2 is reduced.

Comparison of the crimps of the crimped fibers is based on the degree of crimping of the crimped fibers (the number of windings, etc.) located within a distance of 1.6 mm, preferably 1.0 mm, from the joining portion 53 and the joining. It is preferable to compare the degree of crimping (such as the number of windings) of the crimped fiber located in the region 56 surrounded by the part 53 and located at a part 2 mm or more away from any joint part 53.
Or the distribution of the color (liquid) when the colored liquid is dropped from the first fiber layer side can be compared to compare the crimps of the fibers. Specifically, it is also possible to determine by comparing the degree of coloring in the vicinity 57 of the joint within 1.6 mm and the color of the distant 58 longer than 2 mm with the joint 53 as the center.
In the fiber sheet 5 of the present embodiment, the degree of crimping of the crimped fibers (coiled fibers) gradually increases as the joint part 53 is approached.

As described above, the coiled fiber is formed by crimping the latent crimpable fiber. The latent crimpable fiber is a fiber that does not develop crimp before being heated, but has a property that a helical crimp is developed and contracted by heating at a predetermined crimp start temperature or higher. .
The latent crimpable fiber is composed of, for example, an eccentric core-sheath type composite fiber or a side-by-side type composite fiber containing two types of thermoplastic polymer materials having different shrinkage ratios. The thing as described in -296325 gazette and patent 2759331 gazette is mentioned. As an example of two types of thermoplastic polymer materials having different shrinkage rates, for example, a combination of an ethylene-propylene random copolymer (EP) and polypropylene (PP) is preferably exemplified.

  In order to effectively express the above-described various effects resulting from the inclusion of the coiled fiber, the latent crimpable fiber (including the coiled fiber expressing the crimp) is 25 weight in the first fiber layer 51. % Or more is preferable, and 60% by weight or more is more preferable. Moreover, it is not limited to a coiled (spiral) crimp, and may have a two-dimensional crimp, for example, a fiber bent in a zigzag manner.

  The first fiber layer 51 may include fibers other than latent crimpable fibers (including coiled fibers expressing crimps), and latent crimpable fibers (coiled fibers expressing crimps). Examples of the fibers other than the above include various fibers described later as the constituent fibers of the second fiber layer.

  The fiber sheet of the present invention has elasticity in the MD direction and the CD direction, and in both the MD direction and the CD direction, the test piece having a width of 30 mm has an elongation rate of 25% or more and a load of 50 g. The open length after 1 minute is preferably within 110% of the length before elongation from the viewpoint of a fiber sheet having excellent cushioning properties.

The second fiber layer 52 expands the first fiber layer 51 in the plane direction when the fiber sheet 5 is compressed, and the height of the protruding portion 54 due to contraction of the first fiber layer 51 when released from the compression. From the viewpoint of recovering the thickness, the synthetic fiber is preferably contained at 25% by weight or more, more preferably 30 to 80% by weight, and still more preferably 35 to 75% by weight.
As the synthetic fiber, a fiber made of a thermoplastic resin is preferably used. Examples of the constituent resin of the fiber made of a thermoplastic resin include polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, and polyamides. A core-sheath type composite fiber or a side-by-side type composite fiber made of a combination of these thermoplastic polymer materials can also be used.

Moreover, it is preferable that the 2nd fiber layer 52 contains two types of fibers from which average fiber length differs. When two types of fibers having different average fiber lengths are included, as shown in FIG. 3, the first fiber layer 51 is stretched in the plane direction when the fiber sheet is compressed by the fiber 52a having the longer fiber length. The projecting portion 54 having a shape that can be made can be reliably formed.
Further, the fiber 52b having a shorter fiber length is likely to rise from the joint portion 53 as a starting point, and is likely to pierce a member adjacent to the fiber sheet 5 (the upper absorbent layer 41 in the example shown in FIG. 3). As a result, the liquid collected at the joint portion 53 or its vicinity 57 smoothly moves from the fiber sheet 5 to a member adjacent to the fiber 52b as a passage. Thereby, the transfer property of the liquid from the fiber sheet 5 to the member adjacent to it improves.

From the viewpoint of forming the protruding portion 54 having a shape capable of extending the first fiber layer 51 in the plane direction and further improving the liquid transfer property, the fiber having the longer fiber length is made of a synthetic fiber, particularly a thermoplastic resin. The fibers are preferably fibers, and the fibers with shorter fiber lengths are preferably hydrophilic fibers.
As the essentially hydrophilic fiber, cellulosic fibers such as rayon, cotton and pulp are preferably used, and rayon is particularly preferable. Rayon can be used regardless of manufacturing methods, such as a viscose method and a copper ammonia method.
The blending ratio of the essentially hydrophilic fiber in the second fiber layer 52 is preferably 20 to 75% by weight, more preferably 25 to 65% by weight.
Further, the fiber length of the fiber having the longer fiber length is preferably at least longer than the distance between the joint portions 53, more preferably 41 to 120 mm, and most preferably 51 to 100 mm. The fiber length of the fiber having the shorter fiber length is preferably 22 to 70 mm, more preferably 30 to 60 mm.

  In addition, it is preferable that the synthetic fiber in a 2nd fiber layer is a non-heat-shrinkable fiber. Non-heat-shrinkable fibers are heat-shrinkable fibers that show little or no heat-shrinkability, and that do not substantially heat-shrink below the crimp start temperature of the latent crimpable fibers contained in the first fiber layer. Includes sexual fibers.

Further, the shorter fiber (essentially hydrophilic fiber) 52b in the second fiber layer 52 has a fiber diameter larger than that of the longer fiber (synthetic fiber) 52a. It is preferable because it is easy to stand up through the arch (if 52b is relatively thin, it is bent against 52a and cannot protrude).
The preferred thickness of the shorter fiber 52b is 4 dtex or more, more preferably 6.5 dtex or more. The preferred thickness of the longer fiber 52a is at least thinner than the shorter fiber 52b, more preferably 10 dtex or less, and even more preferably 8 dtex or less.

  In the sanitary napkin 1 described above, as shown in FIG. 3, the fiber sheet 5 is arranged in a state where the second fiber layer 52 is in contact with the upper absorbent layer 41 as a hydrophilic fiber layer. The middle-high part 6 of the sanitary napkin 1 is excellent in cushioning properties and liquid absorbability (liquid transfer property to the upper absorbent layer 41). As the hydrophilic fiber layer, a paper made of a piled product of hydrophilic fibers such as pulp fibers, a mixed product of hydrophilic fibers and a superabsorbent polymer, or a pulp fiber covering such a piled fiber, etc. Etc.

Next, a preferred embodiment of the fiber sheet manufacturing method of the present invention will be described.
The manufacturing method of the fiber sheet of this embodiment is a preferable manufacturing method of the fiber sheet 5 described above. As shown in FIG. 4, the first fiber assembly 51a and the second fiber assembly including latent crimpable fibers. By subjecting the laminated body 5a to the body 52a to heat embossing, a large number of joints 53 (see FIG. 2) are formed and spiral crimps are expressed in the latent crimpable fibers in the vicinity of the joints 57. And a step of subjecting the laminated body 5b after forming the joint portion 53 to hot air treatment at a temperature lower than the temperature of hot embossing to shrink the laminated body 5b in both the MD direction and the CD direction. To do.

More specifically, in the present embodiment, as the first fiber aggregate 51a, a strip-shaped card web that includes latent crimpable fibers and is formed by a card machine and is not bonded between constituent fibers is used. As the fiber aggregate 52a, a synthetic fiber (a fiber made of a thermoplastic resin) and an inherently hydrophilic fiber (rayon, etc.) are mixed and formed by a card machine, a belt-like card in which the constituent fibers are not bonded to each other A web was used.
First, the first fiber assembly 51a and the second fiber assembly 52a are laminated as shown in FIG. 4, and a pin (embossing projection) having a circular cross section is formed on the circumferential surface of the laminate 5a. The embossing roll 7 formed in a predetermined pattern is pressed to form a joint portion 53 having a pattern as shown in FIG. The pin of the embossing roll 7 compresses the laminated body 5a between a flat roll (not shown) disposed below.

The pins of the embossing roll 7 can melt the constituent fibers of the first fiber assembly 51a and / or the second fiber assembly 52a, and start shrinkage of the latent crimpable fibers in the first fiber assembly 51a. Heat to a temperature above the temperature.
The temperature of the pin of the embossing roll 7 is in relation to the shrinkage start temperature of the latent crimpable fiber in the first fiber assembly 51a from the viewpoint of generating a coiled fiber in which crimp is expressed in the vicinity of the joint portion 53. The temperature is preferably 15 to 130 ° C., particularly 35 to 90 ° C.
Moreover, it is preferable that the laminated body 5a is kept in contact with the pin of the embossing roll 7 for a relatively long time, and the turning angle θ (see FIG. 4) of the laminated body 5a by the embossing roll is 70 to 220 degrees, particularly 100 to 180 degrees is preferable.

  As shown in FIG. 4, hot air treatment is performed on the laminate 5 b in which the joint portion 53 has been formed in this manner by an air-through heat treatment machine 8. As the heat treatment machine 8, a pin tenter or the like is preferably used. The temperature of the hot air is preferably lower than the temperature of the pin of the embossing roll 7, and more preferably 20 ° C. or lower than the temperature of the pin. Further, the temperature of the hot air is preferably a high temperature within 40 ° C., particularly 3-30 ° C. higher than the shrinkage start temperature of the latent crimpable fiber in the first fiber assembly 51a.

According to the manufacturing method of the present embodiment, at the time of embossing, the helical crimps can be strongly expressed in the latent crimpable fibers located around the joint portion 53, and the heat treatment by the subsequent air-through method is performed. Spiral crimps can be expressed in the latently crimpable fibers of the portion. According to the manufacturing method of this embodiment, the fiber sheet 5 having the above-described configuration can be efficiently manufactured in this manner.
In the hot air treatment, it is preferable that the laminated body 5b on which the joint portion is formed is contracted in both the MD direction and the CD direction, and contracts in both directions so that the dimension is 0.8 times or less of the dimension before contraction. It is preferable from the viewpoint of obtaining a fiber sheet having good cushioning properties.

  Further, in the manufacturing method of the present embodiment, since the web in which the constituent fibers are not bonded is used as the first fiber assembly 51a and the second fiber assembly 52a, the free fiber is used during the embossing process. In a high degree, crimps can be expressed in the latent crimpable fibers near the joint. Thereby, a crimped fiber (coiled fiber) with a large degree of crimp can be reliably formed in the vicinity of the joint.

As described above, the fiber sheet, the manufacturing method, and the absorbent article of the present invention are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of each invention.
For example, in the fiber sheet shown in FIG. 2, a large number of joining portions are formed so that a large number of regions 56 surrounded by twelve joining portions 53 are formed, but as shown in FIG. A large number of junctions are formed so that a large number of regions 56 surrounded by the individual junctions 53 and a large number of regions 56 surrounded by the five junctions 53 are formed as shown in FIG. May be. The junction between the first fiber layer 51 and the second fiber layer 52 is formed such that a region 56 surrounded by about 4 to 30 junctions 53 is continuously formed in the MD direction and the CD direction. It is preferable that the region 56 surrounded by five or more joint portions 53 is continuously formed in the same manner.

Further, the outline shape of the region 56 may be a rectangle, a parallelogram, a triangle, a pentagon, a hexagon, an ellipse, a circle, or the like in addition to a square or rhombus. Further, the shape of each joint portion of the fiber sheet 5 in plan view and the cross-sectional shape of the pin of the embossing roll 7 for forming the same are also round, square, rectangle, rhombus, parallelogram, triangle, pentagon, An arbitrary shape such as a square or an ellipse can be used.
FIG. 6 shows another example of the shape of the joint in plan view and the arrangement pattern of the joint.

  Further, the fiber sheet of the present invention is a sanitary napkin, panty liner (corimono sheet), an incontinence pad, a disposable diaper, etc., between a surface sheet and an absorbent layer, or a part or all of the absorbent layer. Also, it can be used as various components such as a surface sheet. Moreover, it can also be used for various uses other than absorbent articles, such as surgical clothing and a cleaning sheet. Moreover, when providing a middle-high part in an absorbent article, the middle-high part may contact | abut only to a wearer's liquid excretion part, or only the valley between the buttocks behind a liquid excretion part. Moreover, an intermediate | middle high part can also be formed by comprising an absorption layer from an upper absorption layer and a lower absorption layer smaller than this upper absorption layer.

  EXAMPLES Hereinafter, although this invention is further demonstrated using an Example, this invention is not restrict | limited at all by the following example.

[Example 1]
1) Manufacture of first fiber layer (first fiber assembly) Latent crimped fiber (CPP fiber (trade name), 2.2 dtex × 51 mm) manufactured by Daiwa Boseki Co., Ltd. A web of 18 g / m ² was prepared.
2) Production of second fiber layer (second fiber aggregate) PET / PE core-sheath composite fiber (4.6 dtex × 51 mm) manufactured by Chisso Corporation and rayon fiber (8 dtex ×) manufactured by Daiwa Spinning Co., Ltd. 33 mm) was mixed in a weight ratio of 50%, and carded to form a web having a basis weight of 26 g / m ² .
3) Bonding of the first and second fiber layers The above-mentioned two layers of web are overlapped and cut into a length of 1000 mm and a width of 350 mm, and as shown in FIG. Using an embossing pressure plate having an embossed pattern (embossing area ratio 5%), embossing was integrated at a temperature of 220 ° C. and a pressing time of 10 seconds. At this time, a rectangle was drawn in advance at the center of the web with a sign pen, and it was confirmed how much the rectangle contracted before and after embossing. The shrinkage area ratio at this time was defined as “emboss shrinkage ratio R1”.
4) Non-woven fabric (shrinkage integration)
The bonded fiber sheet is set to a predetermined size with a pin tenter and placed in a hot air dryer at an actually measured temperature of 95 ° C. for 90 seconds. The shrinkage ratio in the longitudinal direction is 60% and the shrinkage ratio in the transverse direction is 70% (shrinkage area ratio R = 42% ) Was obtained. The shrinkage rate R includes both the embossing shrinkage rate R1 and the shrinkage rate R2 other than the embossed peripheral edge. In addition, it was considered that the embossing peripheral part did not shrink | contract beyond the process of said 3) in a hot air process of lower temperature.
In the obtained nonwoven fabric (fibrous sheet), the basis weight of the first and second fibrous layer was sequentially ^{43g / m 2, 62g / m} 2.

[Example 2]
For the production of the second fiber layer (second fiber assembly), 40% PET / PE core-sheath composite fiber (2.2 dtex × 51 mm) and 60% rayon fiber (1.8 dtex × 33 mm) are mixed. While using, the nonwoven fabric was obtained like Example 1 except having changed the embossing pattern as shown in FIG.6 (b). The basis weight of the first and second fiber layer in the obtained nonwoven fabric was sequentially ^{43g / m 2, 62g / m} 2.
Example 3
For the production of the second fiber layer (second fiber assembly), 40% PET / PE core-sheath composite fiber (2.2 dtex × 51 mm) and 60% rayon fiber (1.8 dtex × 33 mm) are mixed. While using, the nonwoven fabric was obtained like Example 1 except having changed the embossing pattern as shown in FIG.6 (c). The basis weight of the first and second fiber layer in the obtained nonwoven fabric was sequentially ^{43g / m 2, 62g / m} 2.

Example 4
For the production of the second fiber layer (second fiber assembly), 60% of PET / PE core-sheath composite fiber (2.2 dtex × 51 mm) and 40% of PET single fiber (6.7 dtex × 31 mm) are mixed. And a nonwoven fabric was obtained in the same manner as in Example 1 except that the card pile amount was 20 g / m ² . The basis weights of the first and second fiber layers in the obtained nonwoven fabric were 43 g / m ² and 48 g / m ² in this order.
Example 5
For the production of the second fiber layer (second fiber assembly), PET / PE core-sheath composite fiber (2.2 dtex × 51 mm) 100% was used, and the card pile amount was 16 g / m ² , A nonwoven fabric was obtained in the same manner as in Example 3. The basis weights of the first and second fiber layers in the obtained nonwoven fabric were 43 g / m ² and 38 g / m ² in this order.

[Comparative Example 1]
1) Manufacture of second fiber layer PET / PE core-sheath composite fiber (2.2 dtex × 51 mm) manufactured by Chisso Corporation was carded with a basis weight of 13 g / m ² and immediately subjected to hot air treatment at 145 ° C. for 60 seconds. An air-through nonwoven fabric was prepared.
2) Production of the first fiber layer Latent crimped fiber (CPP fiber (trade name), 2.2 dtex × 51 mm) manufactured by Daiwa Spinning Co., Ltd. was carded to create a web having a basis weight of 12 g / m ² . .
3) Non-woven fabric manufacturing (2 layers combined and shrink integration)
The air-through nonwoven fabric produced in 1) is overlapped with the web produced in 2), cut into a length of 1000 mm × width of 350 mm, and has pins arranged in the same pattern as in Example 1, and a metal other than the pins Embossing was integrated at a temperature of 155 ° C. and a pressing time of 2 seconds using a plate lined with 1.5 mm thick highly foamed silicone rubber.
The fiber sheet after being bonded by embossing is set to a predetermined size with a pin tenter and placed in a hot air dryer at an actually measured temperature of 134 ° C. for 90 seconds to have a longitudinal shrinkage of 70% and a transverse shrinkage of 70% (shrinkage area ratio of 49 %) Non-woven fabric.

[Comparative Example 2]
Chisso Co., Ltd. PET / PE core-sheath composite fiber (2.2 dtex × 51 mm) and Daiwa Boseki Co., Ltd. latent crimpable fiber (CPP fiber (trade name), 2.2 dtex × 51 mm) in weight ratio of 50 % Was mixed and carded to prepare a web having a basis weight of 24 g / m ² . This web single layer was embossed in the same manner as in Comparative Example 1 and subjected to air-through treatment to obtain a nonwoven fabric of Comparative Example 2.

  About the obtained nonwoven fabric (fiber sheet), the stretchability in the MD and CD directions of the fiber sheet is measured as follows, and the compressive properties in the thickness direction of the fiber sheet, the flexibility (flexibility) of the fiber sheet ) Was evaluated. The MD direction of the fiber sheet was the flow direction during card stacking.

(A) MD direction stretchability (elongation rate at 50 g load)
The fiber sheet is cut into dimensions of a width (CD) of 30 mm and a length (MD) of 120 mm to obtain a test piece. The test piece is chucked on a tensile tester (Tensilon RTM-100) manufactured by Orientec Co., Ltd. The inter-space distance was set to 100 mm, and it was pulled at a pulling speed of 10 mm / min until a load of 50 g was reached. The elongation at the time of 50g load was computed by the following formula.
Elongation rate at 50 g load (%) = [(L2-L1) / L1] × 100
(However, L2: Chuck distance at 50g load, L1: Initial chuck distance (= 100mm))

(Percentage of open length after 1 minute of 50g load to length before extension)
Further, the test piece before being stretched was previously marked with two marks at predetermined intervals in the longitudinal direction of the test piece, and the load was 50 g in the measurement of the elongation rate at the time of the 50 g load. At that time, the expansion of the distance between chucks was stopped. After maintaining the state for 1 minute , the test piece was removed, the test piece was spread out without wrinkles, and the distance between the two marks was measured. In this example, two marks were provided at intervals of 50 mm near the central portion in the longitudinal direction of the test piece. The ratio of the open length after 1 minute of 50 g load to the length before extension was calculated by the following formula.
Ratio (%) of the open length after 1 minute of 50 g load to the length before extension = [(L4-L3) / L3] × 100
(However, L4: Distance between marks after release, L3: Distance between marks before extension (= 50mm))

(B) Elasticity in CD direction Except that the fiber sheet is cut into a length (MD) of 30 mm and a width (CD) of 120 mm to obtain a test piece, similarly to the elastic property in the MD direction, with a load of 50 g The elongation ratio and the ratio of the open length after 1 minute of 50 g load to the length before elongation were measured.

(C) Compression characteristics in the thickness direction of the fiber sheet The compression characteristics as an index of cushioning properties are two indices: ease of compression of the fiber sheet under low load and ease of recovery after high load pressurization. Can be judged. That is, the compression rate under the load of 20 gf / cm ² defined below and the thickness recovery rate.
The fiber sheet was cut into 20 mm × 20 mm to prepare a sample.

(Thickness measurement)
A KES compression tester (KES-G5) manufactured by Kato Tech Co., Ltd. was used for the compression test.
Measurement conditions were basically standard conditions, and measurement was performed with a compression head of 10 mmφ and a head speed of 10 mm / min.
In the compression test, the sample was compressed to a load of 50 gf / cm ² by standard measurement (outward path), held at 50 gf / cm ² for 1 minute, and then returned to a load of 0 gf / cm ² by standard measurement (return path).
The compression test was performed in the above process, and the obtained chart was appropriately enlarged, and the following thicknesses were read from the chart and used for the following measurements.

(Initial thickness)
The thickness at 0.5 g / cm ² load (from the forward path data) was defined as the initial thickness L ₀ .
(20 gf / cm ² thickness under load)
The thickness at 20 g / cm ² load (from the forward path data) was L ₂₀ .
(Thickness under 50 gf / cm2 load)
The thickness at 50 g / cm ² load (from the forward path data) was L ₅₀ .
(Recovery thickness)
The thickness at the time of 5 gf / cm ² load on the return path was defined as a recovery thickness L _R.

From the above thickness data, various compression rates and recovery rates were measured as follows.
(Compressibility under 20 gf / cm ² load)
Same compression ratio R ₂₀ (%) = [(L ₀ −L ₂₀ ) / L ₀ ] × 100 (1)
(Thickness recovery rate)
Thickness recovery rate (%) = [L _R / L ₀ ] × 100 (2)
The initial thickness L ₀ and the recovery thickness L _R were set to a thickness under a load of 0.5 gf / cm ² from the viewpoint of eliminating errors due to fluffing and the like. Moreover, when a test piece having a side of 20 mm cannot be cut out, measurement may be performed using a test piece having a smaller area.

(D) Evaluation method of flexibility (flexibility) of fiber sheet A fiber sheet is cut into dimensions of a width (CD) of 200 mm and a length (MD) of 100 mm to obtain a test piece. It mounted | wore to KES bending test machine (KES-FB2) by Corporation | KK, so that the width direction (200 mm side) might become vertical, and standard measurement was performed.
Based on the obtained bending moment B (gf · cm) and the initial thickness (mm) obtained in the item (C), the bending moment is normalized as follows to obtain a flexibility index.
Bending moment per thickness; B / initial thickness (gf · cm / mm)
In addition, when the material width of 200 mm cannot be obtained, the width is measured and measured with a measurable width. When the actual width is W0, the conversion is B / W0 × 200.

  The evaluation results of the fiber sheet are shown in Table 1.

  As can be seen from the results shown in Table 1, it can be seen that all of the samples shown in the Examples are well stretched with a weight of 50 g and are easily restored, that is, excellent in stretchability. In addition, it can be seen that all the samples of the examples are easily compressed with a low load and can be easily restored after being pressed under a high load, that is, excellent in cushioning properties. It can also be seen that the bending stiffness is sufficiently low and the film is softly deformed.

(Manufacture of absorbent articles using fiber sheets of Examples and Comparative Examples)
A sanitary napkin was produced as an absorbent article. The material used for each member and the assembling method are as follows.
Top sheet: The nonwoven fabric produced in Comparative Example 1 was used such that the second fiber layer side formed a skin contact surface and the first fiber layer side faced the upper absorbent layer side.
Upper absorbent layer: pulp 300 g / m ² and water-absorbing polymeric 30 g / m ² were mixed deposited, to obtain a width 30 mm, length 80 mm, an absorber thickness of 8 mm. This was used as the upper absorbent layer.
Fiber sheet: The non-woven fabric (fiber sheet) produced in Example 1 was cut into a width of 55 mm and a length of 110 mm, and the second fiber layer side was overlapped in a direction in contact with the pulp of the upper absorbent layer.
Lower absorbent layer: Pulp 350 g / m ^2, the water-absorbing polymer 50 g / m ² were mixed fiber stacking, wrapped in absorbent paper having a basis weight of 20 g / m ^2. Further, it was compressed with a steel embossing roll (normal temperature / flat pattern) at a contact pressure of 30 kg to obtain a rectangular absorbent sheet having a width of 65 mm, a length of 190 mm, and a thickness of 4 mm. The end of the absorbent sheet in the longitudinal direction was cut into an arc shape to form a lower absorbent layer.
Back sheet: A polyethylene film having a basis weight of 30 g / m ² was used.

Assembling method: An adhesive is spirally coated on the entire surface of the polyethylene film used as a back sheet at a basis weight of 10 g / m ² , and a lower absorbent layer, an upper absorbent layer, and the nonwoven fabric produced in Example 1 (fibers) Sheet) and the surface sheet are laminated in this order, and an embossed groove surrounding the middle and high parts is formed around the middle and high parts, and the peripheral part of the napkin is sealed all around, and then the peripheral part is formed into the shape of the napkin. The product was cut to obtain a sanitary napkin having a product length of 210 mm and a width of 75 mm.

  Moreover, it is the same except that the nonwoven fabric (fiber sheet) interposed between the top sheet and the upper absorbent layer is replaced with the nonwoven fabric (fiber sheet) obtained in Examples 2 to 5 and Comparative Examples 1 and 2, respectively. Thus, a sanitary napkin was prepared.

(E) Measurement of absorption time and wetback amount As preparations, an acrylic injection plate having a hole with a diameter of 10 mmφ (with a cylindrical portion with an inner diameter of 22 mmφ and a height of 40 mm), an acrylic plate, No. The weight of the injection plate so that a load of 5 g / cm ² is applied to the entire surface of the product (or the range of the area where the load is applied to the plate) in advance with 2 filter papers (1 set of 80 x 190 mm), weight, and equine defibrinated blood And the weight of the acrylic plate is adjusted so that a load of 50 g / cm ² is applied.
Spread the product upward and gently place the injection plate on it, and load it to 5 g / cm ² . Weigh 5 g of equine defibrinated blood into a 10 ml beaker and pour it into the cylindrical part of the injection plate at once. The time required for all 5 g of liquid to be absorbed is taken as the absorption time.
One minute after the start of injection, the liquid injection plate was removed, and a pre-weighed No. 2 Place 10 sheets of filter paper on the surface, and further place the acrylic plate and weight gently and apply 50 g / cm ² load for 1 minute. After 1 minute, the plate is removed, 10 filter papers are taken out, and the weight is measured. The increase in weight is defined as a wetback. The three-point average is taken as the measured value.

(F) Wearing test Each sample was given to 20 women, and after wearing, they asked me to select the word that was most comfortable for the next item. The average value of 20 people was taken as the total result. In either case, the smaller the number, the better the result.
Softness: 1. 1. very soft 2. soft Slightly soft 4. 4. I can't say either. Slightly hard 6. Hard fit: 1. Very fit 2. fit A little fit. 4. I can't say either. 4. Does not fit slightly. Don't fit

  The evaluation results for the absorbent article are shown in Table 2.

  As can be seen from the results shown in Table 2, it can be seen that all of the napkins shown in the Examples have a fast blood absorption time and little liquid return. (If a cushion sheet containing short hydrophilic fibers is used for the second fiber sheet as in Examples 1 and 2, the absorption time is particularly fast. Further, if the thickness of the short hydrophilic fibers is large as in Example 1 (hydrophilic It can be seen that both the absorption time and the liquid return are particularly good because the fibers stand up easily and stick into the upper absorbent layer.) Also, the napkin shown in the examples is good for each fiber sheet according to the invention. Reflecting cushioning properties, both softness and fit are very good.

FIG. 1 is a cross-sectional view showing a sanitary napkin, which is an embodiment of the absorbent article of the present invention, including a fiber sheet which is an embodiment of the fiber sheet of the present invention. FIG. 2 is a perspective view showing an embodiment of the fiber sheet of the present invention. 3 is a cross-sectional view taken along line II-II in FIG. FIG. 4 is a schematic view showing an embodiment of a method for producing a fiber sheet of the present invention. FIG. 5 is a schematic view showing the arrangement of the joint portions in another embodiment of the fiber sheet of the present invention. FIG. 6 is a diagram showing an emboss pattern used in the example.

Explanation of symbols

1 Sanitary napkin (absorbent article)
2 Top sheet 3 Back sheet 4 Absorbent layer 41 Upper absorbent layer 42 Lower absorbent layer 5 Fiber sheet 51 First fiber layer 52 Second fiber layer 53 Joint part 54 Projection part 55 Concave part 56 Area surrounded by joint part 57 Joint part Near 58 Distant from joint 6 Middle / high 7 Embossed roll

Claims (5)

A fiber sheet having a stretchable first fiber layer and a second fiber layer, wherein the first fiber layer and the second fiber layer are partially joined to form a joint , and the fiber sheet Is an absorbent article arranged in a state in which the first fiber layer side is directed to the skin contact surface side,
The second fibrous layer, a portion other than the joint, and the first fiber layer side Ri Contact to form protrusions of the convex toward the opposite side, projecting portion of the cross-sectional shape is arcuate,
The first fiber layer includes crimped fibers, and the stretchability is mainly derived from the stretchability of the crimped fibers, and the degree of crimping of the crimped fibers in the vicinity of the joint portion is determined by the joint portion. Greater than the degree of crimp of the crimped fiber in the part far from the
The second fiber layer includes two types of fibers having different average fiber lengths. Of the two types of fibers, the fiber having the longer fiber length is a fiber made of a thermoplastic resin, and the fiber having the shorter fiber length. The fiber is essentially a hydrophilic fiber and a fiber having a fiber diameter larger than that of the thermoplastic fiber,
A comparison of the degree of crimping between the crimped fiber in the vicinity of the joint and the crimped fiber in the part far from the joint is obtained by comparing the crimped fiber located within a distance of 1.6 mm or less from the joint. Absorbability, which compares the degree of crimping with the degree of crimping of crimped fibers located in a region surrounded by a plurality of the joints and located 2 mm or more away from any joints Goods. The fiber sheet has elasticity in the MD direction and the CD direction, and in both the MD direction and the CD direction, the test piece having a width of 30 mm has an elongation rate of 25% or more at 50 g load and after 1 minute of 50 g load. The absorbent article according to claim 1, wherein the ratio of the open length to the length before extension is within 110%. It has a liquid-permeable top sheet, a back sheet and a liquid-retaining absorbent layer interposed between both sheets, and is formed vertically.
In the central part in the width direction, it has a middle and high part that protrudes toward the wearer's skin side, and the absorbent layer in the middle and high part has a structure in which an upper absorbent layer and a lower absorbent layer are laminated,
The fiber sheet, between the topsheet and the upper absorbent layer in the domed section, the and the second fiber layer side is disposed in a state in contact with the upper absorbent layer, according to claim 1 or 2, wherein Absorbent articles. It is a manufacturing method of an absorptive article given in any 1 paragraph of Claims 1-3 ,
The manufacturing process of the fiber sheet forms a large number of joints by applying a heat embossing process to the laminate of the first fiber assembly and the second fiber assembly including the latent crimpable fibers. The step of developing spiral crimps in the latent crimpable fibers in the vicinity of the joint, and the laminate after forming the joint are subjected to a hot air treatment at a temperature lower than the temperature of the hot embossing, and the laminate The manufacturing method of an absorbent article which comprises the process of shrinking | contracting a body to both directions of MD direction and CD direction. The method for producing an absorbent article according to claim 4, wherein a web in which constituent fibers are not bonded to each other is used as the first and second fiber aggregates.

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