JP2875504B2 - Surface sheet for absorbent articles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface sheet for absorbent articles such as sanitary napkins and disposable diapers. More specifically, the present invention relates to absorbent articles such as fit, texture, dry feeling and soft feeling. The present invention relates to a topsheet of an absorbent article having improved physical properties required for the topsheet.

[0002]

2. Description of the Related Art
Perforated films or nonwoven fabrics have often been used as surface sheets for absorbent articles such as sanitary napkins and disposable diapers. When a perforated film is used as a surface sheet, an aperture is provided on the surface of a plastic film as disclosed in Japanese Patent Publication No. 57-17081, etc.
A method of absorbing blood and urine through the opening is employed. However, a perforated film has a sticky feeling peculiar to the film, and since the skin contact surface other than the perforated portion has no air permeability at all, when used as a surface sheet of an absorbent article, Gives a clinging discomfort.

[0003] On the other hand, a nonwoven fabric type topsheet is a hydrophobic sheet having a large number of regularly arranged openings in order to reduce the feeling of body fluid wetting on the skin of the user and to enhance the permeability of body fluid. Top sheets made of nonwovens are known. However, such a topsheet has the drawback that the body fluid hardly moves to the absorber, easily leaks even with a low absorption amount, and easily feels wet and sticky.

[0004] In addition, a surface sheet having an opening in a nonwoven fabric is also known. However, such a topsheet has a problem that the topsheet is clinged to the skin and has a sticky feeling because a portion other than the opening is a planar structure, so that a considerable portion of the surface comes into contact with the skin. For this reason,
There is a demand for a surface sheet that further reduces the contact with the skin and improves the air permeability between the skin and the surface sheet.

Further, Japanese Patent Application Laid-Open No. 4-152945 discloses a nonwoven fabric having three-dimensional openings. However, such a nonwoven fabric has the same problem as the above-described topsheet in which the nonwoven fabric is provided with an opening because the portion other than the opening is a planar structure. In addition, since such a nonwoven fabric is made of fine fibers and has a high fiber density, the nonwoven fabric has a strong tendency to hold a liquid between the fibers by capillary force. Therefore, the liquid absorption / permeability in a portion other than the above-mentioned opening is extremely low. Furthermore,
In order to maintain the shape of the three-dimensional aperture against pressure, it is necessary to increase the fiber density and strength of the nonwoven fabric, and as a result, such nonwoven fabrics generally tend to have a rough feel. .

Accordingly, an object of the present invention is to provide a surface sheet of an absorbent article having improved physical properties required for the absorbent article, such as fit, texture, dry feeling, and soft feeling. .

[0007]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that the bending characteristics (mainly bulk softness), the dense / dense structure, the porosity and the compression characteristics of the surface sheet are determined by the fit, It was found that it is closely related to texture, dry feeling, soft feeling and the like.

[0008] The present invention has been made based on the above findings, and a number of ridges and grooves are alternately arranged so as not to have a plane portion, and the ridges are convexly curved and have the above-mentioned shape. The groove is concavely curved, and the groove is a surface sheet of an absorbent article made of a nonwoven fabric having a large number of apertures arranged at intervals, and is parallel to the ridge and the groove. A ratio (MD / CD) of bulk softness in a direction (MD) to bulk softness in a direction (CD) perpendicular to the ridge portion and the groove portion is 1.7 or more;
The bulk softness in the CD direction is 12 g or less, and the thickness d under a load of 0.5 g / cm ² is 0.7
The above object has been attained by providing a topsheet of an absorbent article characterized by having a thickness of at least 1 mm.

In the following description, a direction parallel to the ridge and the groove will be referred to as an "MD direction", and a direction perpendicular to the ridge and the groove will be referred to as a "CD direction". The “MD direction” and “CD direction” need not coincide with the longitudinal direction or the transverse direction of the absorbent article using the topsheet of the present invention. There is no problem even if it is in the longitudinal direction of the article, and it can be used preferably. Similarly, even if the MD direction of the topsheet of the present invention is the longitudinal direction of the absorbent article, there is no problem and it can be used preferably.

[0010]

In the topsheet of the present invention, the ridges and the grooves are alternately arranged on the nonwoven fabric, so that the direction parallel to the ridges and the grooves and the direction perpendicular to the ridges and the grooves. And the bending characteristics are significantly different. As described above, by controlling the bending characteristics of the topsheet, the fit and texture of the topsheet are improved. Further, since the topsheet of the present invention does not have a flat portion, when used for absorbent articles such as sanitary napkins, the contact area with the skin is reduced,
As a result, the dry feeling of the topsheet is improved. Furthermore, in the topsheet of the present invention, the difference in fiber density (that is, the capillary (A gradient of force), which is used as a driving force to further improve the liquid mobility in the topsheet. As a result, the dry feeling of the topsheet is further improved. In the topsheet of the present invention having such a structure, by the action of the arch-shaped ridges and the lower peripheral edge of the openings having a large fiber density and being structurally strong, the softness of the surface and the shape retention for compression are maintained. Are balanced, and as a result, the soft feeling, the cushioning property, and the expressed texture are improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of a surface sheet of an absorbent article according to the present invention will be described in detail with reference to the accompanying drawings.

Here, FIG. 1 is a plan view showing a preferred embodiment of the topsheet of the absorbent article of the present invention, and FIG.
FIG. 3 is a partial perspective view of the topsheet shown in FIG. 1, and FIG. 3 is a partial cross-sectional view of the topsheet shown in FIG. 1 taken along line AA ′.

As shown in FIGS. 1 and 2, the surface sheet 1 of the absorbent article of the present invention has a large number of ridges 2 and grooves 4 alternately arranged so as not to have a flat portion. Part 2
Is convexly curved and the groove 4 is concavely curved,
The groove 4 is made of a nonwoven fabric having a large number of apertures 6 arranged at intervals.

As the nonwoven fabric, a conventionally known nonwoven fabric can be used without any particular limitation. For example, various nonwoven fabrics such as a nonwoven fabric, a spunbonded nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric, and a needle-punched nonwoven fabric manufactured by a card method can be appropriately selected according to the purpose and application. There is no particular limitation on the means for bonding the fibers in these nonwoven fabrics, and for example, bonding with a binder or bonding by heat fusion can be used. In order to remarkably realize desired properties, particularly improved softness and dryness, a sheet obtained by suction-bonding a heat-fusible fiber web as the nonwoven fabric and forming the nonwoven fabric without undergoing strong compression is most preferable. It is preferably used.

In the present invention, the term "non-woven fabric" includes not only a single non-woven fabric but also various non-opened sheets obtained by compounding non-woven fabrics, non-woven fabrics and films, non-woven fabrics and paper or non-woven fabrics and other materials.

The original thickness of the nonwoven fabric (that is, the thickness of the nonwoven fabric before the openings are formed) and the basis weight are not particularly limited, but the thickness under a load of 0.5 g / cm ² is From the viewpoint of workability, the thickness is preferably 0.4 to 1.5 mm, more preferably 0.4 to 1.0 mm, and still more preferably 0.5 to 0.7 mm. The basis weight, texture, preferably 15~45g / m ² in terms of texture unevenness and workability, more preferably 15 to 35 g / m ^2.

The fibers used in the nonwoven fabric include, for example, polyethylene (PE), polypropylene (P
P), synthetic fibers such as polyesters such as polyethylene terephthalate (PET) and polyamides such as nylon, regenerated cellulose fibers such as rayon and cupra,
And natural fibers such as cotton, but are not limited thereto. In addition, a core-sheath type fiber having a high melting point fiber as a core and a low melting point fiber as a sheath, a side-by-side type composite fiber, and the like are also preferably used. One or more of these fibers can be used. Although the fiber diameter of these fibers is not particularly limited,
It is preferably from 6.0 to 6.0 denier, and more preferably from 1 to 4 denier. If the fiber diameter is less than 0.1 denier, the distance between the fibers becomes small, and liquid residue may occur due to capillary force. If the fiber diameter exceeds 6.0 denier, the concealing property of the nonwoven fabric may be deteriorated. Therefore, it is preferable to be within the above range.

As an example of the nonwoven fabric used in the present invention,
After opening a fiber obtained by blending 70% by weight of a core / sheath type PET / PE composite fiber having a fiber diameter of 2 denier (volume ratio 40/60) and 30% by weight of a PET fiber having a fiber diameter of 6 denier by a carding machine, A suction heat-bonded nonwoven fabric (an apparent thickness of about 0.6 mm under a load of 0.5 g / cm ² and a basis weight of 25 g / m ² ) obtained by fusing the fibers with hot air is exemplified.

A large number of ridges 2 and grooves 4 are alternately arranged in the nonwoven fabric. There is no particular limitation on the arrangement direction of the ridges 2 and the grooves 4 in the nonwoven fabric. For example, the ridges 2 and the grooves 4 are arranged in parallel with the machine direction (longitudinal direction) at the time of manufacturing the nonwoven fabric. Alternatively, the ridges 2 and the grooves 4 may be arranged in a direction (transverse direction) perpendicular to the machine direction, but are not limited thereto. In the present invention, it is preferable to arrange the ridges 2 and the grooves 4 in parallel with the machine direction (longitudinal direction) in view of the bending characteristics of the topsheet and a preferable manufacturing method of the topsheet described later.

As is apparent from FIGS. 2 and 3, the ridges 2 of the present invention are convexly curved, and the grooves 4 are concavely curved. And since the said ridge part 2 and the said groove part 4 are arrange | positioned so that it may not have a plane part, the absorbent article provided with the surface sheet of this invention will reduce the area which a surface sheet contacts with skin, With less stickiness and an improved dry feeling (sarat feeling).

The ridges 2 and the grooves 4 are alternately arranged, and the grooves 4 are formed as continuous surfaces from the ridges 2. As shown in FIG. 3, the interval L between the adjacent ridges 2 is preferably 1.0 to 6.0 mm,
More preferably, it is 1.7 to 3.7 mm. If the distance L is less than 1.0 mm, the pitch is too narrow, so that the height of the ridge portion 2 is not sufficiently secured, and the cushioning property may be impaired. If the distance L exceeds 6.0 mm, the pressure is increased. Since the number of the ridges 2 to be received decreases, the ridges 2 may be easily crushed. For the same reason, the interval M between the adjacent groove portions 4 is preferably 1.0 to 6.0 mm,
More preferably, it is 1.7 to 3.7 mm.

As shown in FIGS. 1 and 2, the groove 4 is
It has a number of apertures 6 arranged at intervals. The opening 6 is preferably formed by being surrounded by a nonwoven fabric extending from the front surface 8A to the back surface 8B of the topsheet 1 of the present invention, as shown in FIG. And
The inner wall 10 of the opening 6 is formed as a continuous surface from the surface 8A. That is, the opening 6 is preferably a three-dimensional opening. Examples of the three-dimensional opening include an opening in which the nonwoven fabric surrounding the opening has a cylindrical shape, and a diameter of the opening 6 is from the front surface 8A to the back surface 8A.
A conical opening or the like that gradually increases toward B may be mentioned. Preferably, as shown in FIG. 3, the diameter of the opening 6 gradually decreases from the front surface 8A toward the back surface 8B. Several inverted conical apertures are preferred.

As shown in FIG. 1, the interval N between the adjacent openings 6 in the groove 4 is preferably 0.4 to 40 mm, more preferably 1.5 to 8 mm. If the interval N is less than 0.4 mm, the perimeter of the opening 6 becomes small, and the periphery of the opening 6 may not be formed firmly. It is preferable to be within the above-mentioned range, because the presence may be coarse and the permeability of the liquid through the opening 6 may be low.

The shape of the opening 6 is not particularly limited, and may be, for example, an elliptical, triangular or square opening, but a circular opening without anisotropy improves the softness of the topsheet. It is preferable from the point of making.

When the groove 4 has a circular or elliptical opening 6, as shown in FIG. 4 which is an enlarged view of FIG. 3, the diameter c of the lower peripheral edge of the opening 6 is 0.5 to 2 mm. 0.0 mm, more preferably 0.7 to 1.5 mm. If the diameter c is less than 0.5 mm, the ridge 2
When the diameter c exceeds 2 mm, the fibers gathered at the lower peripheral edge of the opening are fused and fused, so that a sufficient capillary force for liquid transfer to the lower peripheral edge 12 cannot be obtained. Since the film may be formed, it is preferable to be within the above range.

The ridge 2, the groove 4, and the opening 6
Can be formed, for example, according to a preferred method of manufacturing the topsheet of the present invention described below.

When the surface sheet of the present invention is incorporated into an absorbent article, the above-mentioned surface 8A is used as a surface in contact with the skin.

As described above, in the topsheet 1 of the present invention in which the openings 6 are formed, the gap between the openings is convex, so that the liquid easily collects in the openings, and the liquid permeability is good, so There is no pool. Also, no return of blood or the like once absorbed on the back surface 8B side of the topsheet 1 of the present invention is observed.

In the topsheet of the present invention, the softness is improved by paying particular attention to its bending characteristics (mainly bulk softness) and its compression characteristics (mainly thickness and repulsive stress to compression). . That is, in the topsheet of the present invention, the bulk softness in the MD direction,
The ratio to the bulk softness in the CD direction (MD /
CD) is 1.7 or more, the bulk softness in the CD direction is 12 g or less, and 0.5 g / cm
⁽²⁾ The thickness d under a load is 0.7 mm or more. Hereinafter, these physical properties will be described in more detail.

As described above, in the topsheet of the present invention, the bulk softness in the MD direction and the C
Ratio to bulk softness in D direction (MD / CD)
Is 1.7 or more. That is, the topsheet of the present invention is easily bent selectively in the CD direction. When the above ratio is less than 1.7, when the absorbent article provided with the topsheet of the present invention is mounted, the topsheet is rigid when the topsheet is bent in the CD direction. Roughness and Katasa are perceived. The higher the ratio, the better, for example, preferably 1.9 or more, more preferably 2.0 or more.

The isotropic reduction of the hardness of the entire topsheet can be achieved by, for example, reducing the basis weight of the topsheet more than necessary or adjusting the heat treatment temperature. In such a case, the strength of the topsheet is reduced, and the topsheet may become fuzzy at the time of use or break in an extreme case, which is not preferable.

In the topsheet of the present invention, when the bulk softness (flexural rigidity) in the MD direction and the CD direction is given anisotropy as described above, sufficient mechanical strength can be maintained in the MD direction. The above-mentioned problem does not occur even when a very flexible sheet is prepared. In this case, the bulk softness value required for clearly recognizing the soft feeling is 12 g or less in the CD direction. When the bulk softness value exceeds 12 g, the nonwoven fabric having a bulk softness ratio of 1.7 or more in the MD / CD direction becomes more conscious of the hardness and shows an improved texture. Absent. The above CD
The bulk softness value in the direction is preferably 2 to 7 g, more preferably 3 to 6 g.

Also, 0.5 g / c of the topsheet of the present invention is used.
The thickness d under a load of m ² is 0.7 mm or more. By setting the thickness d to 0.7 mm or more, a surface sheet having a bulky and improved soft feeling can be obtained. If the basis weight of the top sheet is increased (for example, 60 to 100 g)
/ M ² ) It is easy to make the thickness d 0.7 mm or more, but in that case, it may be difficult to make the bulk softness in the CD direction 12 g or less. On the other hand, in the present invention, even when the basis weight of the topsheet is not large, the thickness d is 0.7 mm or more due to the three-dimensional action caused by the curved ridges and grooves. It is easy to do. Further, by making the opening in the groove portion three-dimensional as described above, it is easier to make the thickness d 0.7 mm or more.

In a preferred embodiment of the present invention, in addition to the surface sheet of the present invention having the above structure and the above physical properties, the sheet has a gradient in the thickness of the sheet in the cross section in the CD direction. In the topsheet of the present invention, since the abundance of fibers is substantially the same in any part, the fact that the thickness of the sheet has a gradient means that, in other words, the sheet per unit area in the cross section in the CD direction. This means that there is a gradient in fiber density. That is, a portion where the thickness of the sheet is large is a portion where the fiber density is low, and the fibers are sparsely present and have a soft feeling. On the other hand, a portion where the thickness of the sheet is small is a portion where the fiber density is high, and the fibers are densely present and have a rigid feeling.

As for the method of providing the gradient, for example, FIG.
As shown in the above, the difference (ab) between the maximum sheet thickness a of the ridge portion and the sheet thickness b of the lower edge portion of the opening in the cross section in the CD direction of the topsheet of the present invention is 200 μm or more. It is preferred to provide a gradient as is. By setting the difference (ab) to 200 μm or more, a large sparse / dense structure is formed on the top sheet, and a portion having moderate softness and softness (a portion having a small fiber density) and a body pressure are formed in one sheet. A rigid portion (a portion having a high fiber density) that does not collapse even when the sheet coexists, thereby achieving an appropriate cushioning property of the entire sheet. Also, the presence of the rigid portion maintains a constant thickness even when the topsheet is crushed by body pressure, and prevents the liquid absorbed by the absorber from returning.

Further, the portion where the fiber density is large (mainly, the peripheral edge of the lower end of the opening) is densely filled with fibers.
The liquid existing on the surface of the topsheet is sucked by capillary force, and is quickly led to the absorber. On the other hand, the portion having a low fiber density (mainly, the top of the ridge) has a weak capillary force because the fibers are sparsely present, and as a result, the liquid once absorbed by the absorber absorbs the liquid of the topsheet. It is difficult to return to the surface. As described above, when the topsheet of the present invention has a dense and dense structure, a gradient of capillary force is generated in a single structure, the liquid residue on the surface is reduced, and the dry feeling is further improved.

In the topsheet according to the present invention, the difference (ab) is at least 200 μm (particularly preferably 300 μm).
５００500 μm), and the diameter c of the peripheral edge at the lower end of the opening is 0.5 to 2.0 mm (particularly preferably 0.7 to
1.5 mm), a particularly good soft feeling can be obtained.

The maximum sheet thickness a of the ridge may be at any position of the ridge, but is preferably at the top of the ridge. When the maximum sheet thickness a of the ridge portion is at the top of the ridge portion, the cushioning property of the ridge portion is further improved, and a better soft feeling is obtained.

More preferably, the C of the topsheet of the present invention is
The sheet thickness in the cross section in the D direction is the largest at the top of the ridge, the smallest at the lower edge of the opening, and
It gradually decreases from the top of the ridge toward the lower edge of the opening. That is, as shown in FIG. 4, the sheet thickness a at the top of the ridge portion, the sheet thickness b at the lower peripheral portion of the opening, and the sheet thickness a ′ at a substantially intermediate portion between the top portion and the lower peripheral portion. It is preferable that a> a ′> b be satisfied and the sheet thickness is continuously reduced. By adjusting the sheet thickness in this manner, the cushioning property is further improved, and a better soft feeling is obtained.

The above-mentioned dense structure can be obtained preferably according to a preferred method for producing a topsheet of the present invention which will be described later.

As still another embodiment of the cross section in the CD direction of the topsheet 1 of the present invention, a topsheet having a cross section as shown in FIG. 5 is also preferable. In the embodiment shown in FIG.
The rear surface 8B of the top of the ridge portion 2 in the cross section in the CD direction of the topsheet 1 of the present invention projects toward the front surface 8A. In this case, the maximum sheet thickness a of the ridge 2 is determined by the top of the ridge 2 and the lower peripheral edge 1 of the opening 6.
Between two. And also in the aspect shown in FIG. 5, it is particularly preferable that the difference (ab) is 200 μm or more, and the diameter c of the lower edge of the opening is 0.5 to 2.0 mm. When the sheet thickness at the top of the ridge portion 2 is α, and when the sheet thickness at a substantially intermediate portion between the portion where the maximum sheet thickness a exists and the peripheral edge at the lower end of the opening is β, a> It is also preferable that there is a relationship of α, a>β> b. Since the cross section in the CD direction of the topsheet of the present invention has such a structure, the absorbent article provided with the topsheet of the present invention is mounted, and the structure of the ridge portion is further maintained when pressure is applied. It is preferable because it becomes certain.

In a further preferred embodiment of the present invention, the topsheet of the present invention has the above-mentioned structure and the above-mentioned physical properties, and also has the following compression characteristics. That is, the topsheet of the present invention has a thickness d under a load of 0.5 g / cm ² of 0.7 to 2.0 mm and a rebound stress of 5 to 30 g when compressed to a thickness of 0.6 mm. Preferably, there is. By the surface sheet of the present invention having such compression characteristics, the above structure is maintained even under the pressure applied when the absorbent article is actually mounted, and the appropriate softness and cushioning property are obtained while satisfying the above various physical properties. Can be

In the above compression properties, 0.5 g / cm
The thickness d under ^two loads corresponds to the thickness of the topsheet when the user starts touching the topsheet lightly. If the thickness d in this case is less than 0.7 mm, a plump feel cannot be obtained and the soft feeling may not be sufficient.
If it exceeds 0 mm, the liquid absorbability may be impaired, so it is preferable to be within the above range. 0.5g / cm
² The thickness d under load is more preferably 0.7 to 1.5.
mm, and more preferably 1.0 to 1.4 mm.

The repulsive stress refers to a resistance force returned from the top sheet to compression, and can be measured by a KES compression measuring device as described later. The repulsion stress is a force directly related to the structure retention and cushioning properties of the topsheet. If the repulsion stress is less than 5 g, the structure in the topsheet easily collapses when the absorbent article is mounted. In addition, it may not be able to be maintained, and may not be able to provide an improved feeling because the cushioning property is lost and the feel becomes thin and hard. On the other hand, when the repulsion stress exceeds 30 g, the surface of the topsheet becomes poor in flexibility, and the absorbent article may feel rough when worn. Therefore, it is preferable to be within the above range. The repulsion stress is 7 to
The weight is more preferably 25 g, and even more preferably 7.5 to 20 g.

In another preferred embodiment of the present invention, the surface sheet of the present invention has the above-mentioned structure and the above-mentioned physical properties, and also has the following compression characteristics. That is, the topsheet of the present invention has a thickness d of 0.7 to 2.0 mm (more preferably 0.7 to 1.5 mm, more preferably 1.0 to 1) under a load of 0.5 g / cm ^2. .4m
m) and the repulsion stress F at 30% compression is 3 to 10 g
It is preferred that When the topsheet of the present invention has such a compression property, the cushioning property in the ridge portion is further improved, and a more favorable soft feeling is obtained. Further, the smoothness of the surface is further improved.

The above "30% compression" is 0.5 g / c
It means that it is compressed by 30% with respect to the thickness d under the load of m ^{2, and} the thickness in that case is represented by the following formula (I).

[0047]

(Equation 1)

When the repulsion stress F is in the range of 3 to 10 g, the cushion feeling felt when the top sheet is lightly pressed is moderately felt, which is preferable. If the repulsion stress F is less than 3 g, the topsheet may be easily crushed and give a thin and hard impression as a whole. On the other hand, when the repulsion stress F exceeds 10 g, the structure becomes hard and rough, and it may be difficult to obtain an improved feeling.

The repulsion stress F is more preferably 3 to 8
g, and more preferably 3.5 to 7.5 g.

In the topsheet of the present invention, it is important to enhance the liquid absorbing ability through the apertures, and to sufficiently form the above-mentioned dense / dense structure to enhance the liquid absorbing ability also by the capillary force gradient. . For this purpose, the porosity of the topsheet of the present invention is preferably 7% or more. If the opening ratio is less than 7%, the fibers may not be sufficiently gathered to the peripheral edge at the lower end of the opening, and a sufficiently dense structure may not be formed. More preferably, the porosity is 10 to 20%. Note that the opening ratio is a value obtained by dividing the area of the opening formed when the topsheet of the present invention is projected from the front surface 8A to the back surface 8B by the area of the topsheet. The specific measuring method will be described later.

Next, a preferred embodiment of the absorbent article provided with the topsheet of the present invention will be described in detail with reference to FIG.

Here, FIG. 6 is a perspective view showing a sanitary napkin as an absorbent article provided with the topsheet of the present invention.

The sanitary napkin 14 shown in FIG. 6 includes the topsheet 1 of the present invention, a liquid-impermeable backsheet (not shown), and an absorber (not shown). The absorber is
The surface of the sanitary napkin 14 is covered with the back sheet except for the surface that comes into contact with the skin. Further, the surface of the absorbent body that comes into contact with the skin among the surfaces of the sanitary napkin 14 is covered with the topsheet 1. Further, the topsheet 1 covers the entire absorber.

In the sanitary napkin 14,
The description of the conventional sanitary napkin is appropriately applied to the points not particularly described.

By providing the sanitary napkin 14 with the topsheet 1 of the present invention, such a sanitary napkin is excellent in texture, liquid permeability, liquid return prevention and cushioning properties.

That is, in the sanitary napkin 14 provided with the topsheet 1 of the present invention, first, the portion of the topsheet 1 which is in contact with the skin is small, and the portion of the topsheet 1 which is in contact with the skin has the original soft feel of the nonwoven fabric. Therefore, a comfortable wearing feeling is obtained,
In addition, the feeling of wetness after absorbing body fluid can be reduced.

Second, since the topsheet 1 of the present invention is three-dimensional, the topsheet 1 does not include a flat portion or a pool of blood, and blood can be quickly absorbed by the absorber through the opening 6. . Therefore, when the sanitary napkin is worn,
There is no sticky feeling clinging to the skin, and it is excellent in dry feeling.

Third, in the cross section in the CD direction, since the topsheet 1 of the present invention has a sparse / dense structure, even if body pressure is applied to the topsheet 1, the cushioning property is good. Does not get smaller. Therefore, a certain distance is maintained between the topsheet 1 and the absorber, and it is possible to prevent body fluids such as blood once absorbed from returning to the surface 8A of the topsheet 1 from the absorber.

Although the sanitary napkin has been described as an example of the absorbent article using the topsheet of the present invention, the absorbent article using the topsheet of the present invention is not limited to this. The topsheet of the invention is
The present invention can be applied to other absorbent articles, for example, hygiene pads, nursing pads, disposable diapers, and the like without any particular limitation.

Next, a preferred method for producing the topsheet of the present invention will be described in detail.

The topsheet of the present invention can be produced by mechanically opening the nonwoven fabric as described above.
More specifically, a pin roll (first pressing die) having a large number of pyramidal or conical convex pins arranged in a row along the transport direction of the nonwoven fabric, and the rows being arranged in multiple rows. Producing a topsheet having the above structure by interposing the nonwoven fabric between a ridge roll (a second pressing die) having a ridge portion fitted between the multi-row convex pins. Can be.

In the above-described manufacturing method, the pin rolls are arranged such that the convex pins are arranged in rows along the direction of transport of the nonwoven fabric, and the rows are arranged in multiple rows. On the other hand, in the ridge roll, the ridge portion is fitted between rows of the convex pins of the pin roll.

As a result, the ridges of the topsheet of the present invention are easily formed by the ridges of the ridge roll, and the ridges of the pin roll are pressed against the nonwoven fabric by the convex pins. A groove and the opening are formed. Further, in this case, the pin roll is set at 60 to 26.
When used at a temperature of 0 ° C., the nonwoven fabric (that is, the nonwoven fabric that extends from the front surface to the rear surface and forms the opening) that is in contact with the peripheral edge of the convex pin is partially softened or partially heated. By specifically melting, the density of the peripheral edge at the lower end of the opening can be made higher than that of other portions (that is, the thickness of the sheet can be reduced). In order to enhance the formability of the ridge, before introducing the nonwoven fabric into the roll, for example, hot air (for example, 60 to 260 ° C.) may be blown on the nonwoven fabric, or the nonwoven fabric may be preheated with a preheat roll (for example, 60-260 ° C)
It is also preferable to perform a pre-heat treatment known to those skilled in the art, such as winding the non-woven fabric, and heat the nonwoven fabric in advance.

Further, when producing a topsheet as shown in FIG. 5, the ridge roll may be heated to 60 to 260 ° C. in the same manner as the pin roll.

Next, the surface sheet of the present invention will be described in more detail with reference to the following Examples, but the scope of the present invention is not limited to these Examples.

Example 1 A nonwoven fabric shown in Table 1 was used as a raw material, and a surface sheet of the present invention having a sectional shape shown in FIG. Table 2 shows various physical properties of the topsheet. In addition, the measuring method of the physical property value in Table 2 is as follows.

<Bulk Softness>
The maximum load (buckling strength) when a test piece obtained by cutting out a piece of 50 mm x 30 mm into a cylinder having a diameter of 45 mm and a height of 30 mm and compressed at a speed of 10 mm / min with a Tensilon compression tester was measured. Ness (g). The compression direction in this case is the height direction of the cylinder. The bulk softness in the MD direction refers to the bulk softness when the MD direction of the topsheet is set as the compression direction. Similarly, the bulk softness in the CD direction refers to the bulk softness when the CD direction of the topsheet is the compression direction. The value is a representative value with an average value of 5 points.

<Thickness d under a load of 0.5 g / cm ² > K
ES compression tester (KES FB manufactured by Kato Tech Co., Ltd.)
-3), a compression property test was performed on the above surface sheet in a normal test mode up to 50 g / cm ² ,
The thickness d (mm) under a load of g / cm ^{2 is} read from the chart.

<Difference in Surface Sheet Thickness (ab)> The surface sheet was cut out as shown in FIG.
Take an enlarged photograph of the cross section. Figure 4 based on the photograph taken
Then, the dimensions of a and b are read, and ab (μm) is calculated. The value is a representative value with an average value of 5 points. The sheet thicknesses a and b are determined at predetermined positions on the surface 8A side (or the inner wall 10 side) of the topsheet (for example, in the case of the sheet thickness b, at the lower peripheral edge of the opening). Measured in the direction perpendicular to the tangent.

<Aperture diameter c> Using an image analyzer "Excel" manufactured by Nippon Avionics Co., Ltd., an image of the above-mentioned top sheet pasted on a black mount was input, and a black and white binarization process was performed on the screen. The white portion corresponds to the opening. The diameter of the circular portion is calculated from the area of the white portion when the circular portion is formed into a circular shape, and is defined as an opening diameter c (mm).

<Repulsion stress at 0.6 mm compression>
The same measurement as the measurement of the thickness at 5 g / cm ² is performed, and the stress at the time of compression of 0.6 mm is read from the chart, which is defined as the repulsion stress (g).

<Repulsion stress F at 30% compression> 0.5
The thickness at 30% compression is calculated based on the thickness at g / cm ² , the stress at that thickness is read from the chart, and this is defined as the repulsion stress F (g).

<Pore Opening Ratio> Using the image analyzer “Excel” manufactured by Nippon Avionics Co., Ltd., the above-mentioned top sheet pasted on a black mount is input as an image, and the black and white area ratio on the screen is calculated. At this time, since the white area on the screen corresponds to the aperture, the white area with respect to the entire screen area is defined as the aperture ratio (%).

Further, the above-mentioned topsheet was subjected to a sensory evaluation on softness, plumpness and feel by the following method. Table 3 shows the results.

<Sensory Evaluation> Twenty-five women were allowed to touch the above-mentioned topsheet, and the following items were selected to give the closest impression. The number of each item in Table 3 is the average value of the evaluation points, and has the following meaning. [1] Softness 5; Soft, 4; Slightly Soft, 3; Neutral, 2; Slightly Hard, 1; Hardness The larger the average value, the better the softness. [2] Plump feeling 5; plump 4; slightly plump 3; neutral;
2; not somewhat full; 1; not full. The larger the average value, the better the texture. [3] Hand feeling 5; good, 4; slightly good, 3; neutral, 2; slightly bad,
1; poor The larger the average value, the better the feel.

Next, a sanitary napkin using the above surface sheet was prepared in the following procedure. That is, basis weight 250 g /
The pulp piled up to m ² was wrapped with absorbent paper having a basis weight of 20 g / m ² to prepare an absorber having a length of 170 mm, a width of 70 mm and a thickness of 12 mm. Roll up this absorbent body with waterproof paper, wrap it with the above surface sheet as a surface material,
Further, a sanitary napkin was manufactured by applying a slip-resistant adhesive to the lower surface side. With respect to this sanitary napkin, the evaluation of the feeling of wearing and the measurement of the remaining amount of the liquid were performed by the following methods. Table 3 shows the results.

<Evaluation of Wearing Feeling> Twenty-five women who performed a sensory evaluation of the above-mentioned topsheet were asked to use the above-mentioned sanitary napkins, and to select the most impressive expression for the feeling of wearing. The numbers in Table 3 are average values of the evaluation points and have the following meanings. 5; Good, 4; Somewhat good, 3; Neutral, 2; Somewhat bad,
1; bad The larger the average value, the better the feeling of wearing.

<Liquid Remaining Amount> 3 g of horse defibrinated blood is injected into the sanitary napkin, left for 1 minute under no load, then mounted on a dynamic human body model, and the model is allowed to walk for 30 minutes. The weight of the surface sheet of the sanitary napkin is measured in advance, and the value obtained by subtracting the original weight from the weight of the surface sheet removed from the sanitary napkin after walking is the remaining amount of liquid (g) remaining on the surface sheet. I do. The smaller the remaining amount of the liquid, the more the surface sheet becomes non-sticky and slatted.

[Examples 2 to 5 and Comparative Examples 1 to 4] Using the nonwoven fabric shown in Table 1 as a raw material, a surface sheet was produced in the same manner as in Example 1. Table 2 shows various physical properties of the obtained topsheet. Further, the obtained topsheet was subjected to the same sensory evaluation as in Example 1. Table 3 shows the results. In addition, obtained in Example 2 and Comparative Examples 1-4.
The obtained topsheet has the cross-sectional shape shown in FIG.
The topsheets obtained in Examples 3 to 5 are shown in FIG.
It has a cross-sectional shape. Next, a sanitary napkin was produced using the obtained topsheet in the same manner as in Example 1, and the evaluation of the feeling of wearing and the measurement of the remaining amount of liquid were performed in the same manner as in Example 1. Table 3 shows the results.

[0080]

[Table 1]

[0081]

[Table 2]

[0082]

[Table 3]

As is clear from the above results, Examples 1 to
In the topsheet obtained in No. 5, a high evaluation was obtained for all of the softness, plumpness, and touch, and also a high evaluation for the wearing feeling of the sanitary napkin manufactured using such a topsheet. And the remaining amount of liquid is small.

On the other hand, the topsheet obtained in Comparative Example 1 has no openings, and the topsheet obtained in Comparative Example 3 has insufficient openings and no ridges. Therefore, the feeling of the sheet is poor and the feeling of the sheet is not improved, and the improved feeling of wearing is not obtained. In addition, there is neither liquid permeation due to the opening nor liquid movement due to the dense and dense structure of the fibers, so that the amount of liquid remaining is large.

A topsheet having a flat opening (Comparative Example 4) produced by spunlace also has a poor plumpness. In addition, since the fiber aggregate density in the portion other than the holes is large, the amount of liquid remaining is large despite the holes being opened.

Further, in the topsheet obtained in Comparative Example 2, the ridges were formed firmly and the compression characteristics were too high.
Although the remaining amount of the liquid is small and the effect of improving the absorption performance is recognized, the feel is deteriorated, and it is not suitable for use as a topsheet.

[0087]

According to the present invention, it is possible to obtain a topsheet of an absorbent article having improved fit and texture by controlling its bending characteristics. In addition, in addition to the above-mentioned effects, since the topsheet has a sparse / dense structure, liquid residue is reduced, and a topsheet excellent in dry feeling can be obtained. Furthermore, by controlling the compression characteristics of the topsheet in addition to the above, a topsheet with an improved softness can be obtained in addition to the above effects.

[Brief description of the drawings]

FIG. 1 is a plan view showing a preferred embodiment of a topsheet of an absorbent article of the present invention.

FIG. 2 is a partial perspective view of the topsheet shown in FIG.

FIG. 3 is a partial cross-sectional view taken along line AA ′ of the topsheet shown in FIG. 1;

FIG. 4 is an enlarged view of a partial sectional view shown in FIG. 3;

FIG. 5 is a diagram showing still another embodiment of the partial cross-sectional view shown in FIG. 3;

FIG. 6 is a perspective view showing a sanitary napkin as an absorbent article provided with the topsheet of the present invention.

[Description of Signs] 1 Topsheet of absorbent article 2 Ridge 4 Groove 6 Opening 8A Surface 8B Backside 10 Inner wall 12 Lower peripheral edge 14 Sanitary napkin

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) D04H 13/00 A61F 13/15 A61F 13/54 D06M 17/00

Claims (6)

(57) [Claims] 1. A large number of ridges and grooves are alternately arranged so as not to have a plane portion, the ridges are convexly curved, and the grooves are concavely curved. A topsheet of an absorbent article comprising a nonwoven fabric having a large number of apertures arranged at intervals, the bulk softness in a direction (MD) parallel to the ridge and the groove, and the ridge. Ratio to the bulk softness in the direction (CD) perpendicular to the groove and the groove (MD / C
D) is 1.7 or more, the bulk softness in the CD direction is 12 g or less, and 0.5 g / cm ^2.
A surface sheet for an absorbent article, wherein the thickness d under a load is 0.7 mm or more. 2. A difference (ab) between a maximum sheet thickness a of the ridge portion and a sheet thickness b of a lower peripheral portion of the opening in the cross section in the CD direction is 200 μm or more, and the opening is 2. The topsheet according to claim 1, wherein the diameter c of the lower peripheral edge of the topsheet is 0.5 to 2.0 mm. 3. The surface sheet according to claim 2, wherein the maximum sheet thickness a of the ridge portion is at the top of the ridge portion. 4. The thickness d under a load of 0.5 g / cm ² is 0.7 to 2.0 mm, and the rebound stress when compressed to a thickness of 0.6 mm is 5 to 30 g. The topsheet according to 1. 5. The surface sheet according to claim 1, wherein the thickness d under a load of 0.5 g / cm ² is 0.7 to 2.0 mm, and the rebound stress at 30% compression is 3 to 10 g. . 6. The surface sheet according to claim 1, wherein the porosity is 7% or more.