JPH08260329A - Method and device for manufacturing three-dimensional apertured sheet - Google Patents

Abstract

(57) [Summary] (Modified) [Objective] To provide a method and an apparatus for manufacturing a three-dimensional apertured sheet having a structure capable of effectively transferring liquid from the surface layer to the back layer. A first push die having a large number of convex pins 20 arranged in a row and the rows being arranged in multiple rows, and a concave die fitted into the convex pins 20 or a protrusion fitted between the multiple rows. In a method of manufacturing a three-dimensionally open sheet having a large number of three-dimensional holes by interposing a sheet between the second pressing die having a strip portion, a pillar-shaped base portion 12 as the convex pin 20, The cone-shaped tip portion 14 and the collar portion 1 extending in a direction substantially perpendicular to the axial direction of the base portion 12 at a substantially boundary portion between the base portion and the tip portion 14.
8. A method for producing a three-dimensional apertured sheet using a convex pin 20 composed of 8 or, as the convex pin 20, the tip portion 14 is composed of a skirt portion 40 and a top portion 42, and the tip angle of the top portion is A pin is used that is larger than the crossing angle of the extension lines of the two ridge lines facing each other in the skirt portion toward the top.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for producing a three-dimensional apertured sheet, and more particularly to the production of a three-dimensional apertured sheet that is suitable for use as a surface sheet for absorbent articles such as sanitary napkins and disposable diapers. A method and apparatus.

2. Description of the Related Art

[0002] Conventionally, perforated films and non-woven fabrics are generally often used as surface sheets for absorbent articles such as sanitary napkins and disposable diapers. The technique of using a perforated film as a surface sheet of an absorbent article is disclosed, for example, in Japanese Examined Patent Publication No. 57-17081 and Japanese Unexamined Patent Publication No. 62-68928.
It is described in Japanese Patent Publication No. When the perforated film is used as a surface sheet of an absorbent article, an absorbent article having a relatively excellent dry feeling can be obtained, but the perforated film itself clings to the skin and gives a sticky feeling to the user. Further, the perforated film may cause a rash.

On the other hand, although the non-woven fabric has a good feel to the skin, since it is composed of fibers, there is a problem in that a liquid residue is liable to occur between the fibers due to a capillary force, resulting in a poor dry feeling. Further, recently, a non-woven fabric having pores is known for the purpose of increasing the liquid passing speed and reducing the contact area with the skin. For example, JP-A-63-182460 describes a method of obtaining a nonwoven fabric having irregular pores by jetting a high-pressure water stream to the fiber material layer to rearrange the fibers. Further, Japanese Patent Application Laid-Open No. 3-90669 describes a method in which fibers are divided into nets by a high-pressure water flow to provide openings. In the perforation method using these high-pressure water streams, the original thickness of the nonwoven fabric is crushed due to the pressure of the high-pressure water stream, so the resulting apertured nonwoven fabric has poor cushioning properties and has the drawback of easily returning liquid. . Further, there is a drawback that the fiber density becomes high as a whole, and liquid remains easily.

In order to reduce the liquid return of the above-mentioned open-pore nonwoven fabric, JP-A-4-89054 and 4-152.
In 945, it is proposed to form a three-dimensional opening by depositing ultrafine fibers formed by jetting a molten polymer by a melt blow method on a mold for shape setting. ing. However, although this type of three-dimensional open-pore nonwoven fabric is recognized to have an effect of preventing liquid return upon pressurization, the liquid discharged to the non-open pores is considerably taken in between the fibers constituting the nonwoven fabric due to capillary force. . In this case, if there is a large space between the non-woven fabric and the absorbent body, the liquid taken in between the fibers is not absorbed by the absorbent body and remains as a liquid.

Further, as a method of forming a three-dimensional opening, a method of mechanically opening a sheet is also known. For example,
JP-A-52-27876 and JP-A-62-1250
Japanese Patent No. 61 discloses a method in which a nonwoven fabric sheet is sandwiched and opened between a needle protruding outward and a pushing body. Further, in Japanese Unexamined Patent Publication No. 6-330443, a large number of large numbers are prepared by inserting a second pressing die (roll) having a ridge into a first pressing die (roll) having a conical or pyramidal convex pin. A method of forming a stereoscopic aperture is described.

In the mechanical perforation method, it is important to maximize the diameter of the convex pin to increase the porosity of the sheet. However, if the convex pin is deeply pierced into the sheet in order to increase the aperture ratio, the resistance when pulling out the convex pin becomes very large, and the formed three-dimensional aperture is inverted to the opposite side of the sheet. The shape will be distorted even if it is lost or not reversed. Further, due to the rotational movement of the roll, when the convex pin comes out, the convex pin swings its neck and re-contacts with the formed opening, and scratches the opening. As a result, the shape of the aperture is disturbed, not only is it unsightly in appearance, but also comes into contact with the convex pin, a softened / melted and hardened portion appears on the surface of the sheet, and a rough feeling is generated. The texture is remarkably deteriorated. Also,
Along with these phenomena, the porosity of the sheet decreases, and the liquid absorption performance also decreases.

That is, in the above mechanical perforation method, when the sheet is perforated by using the pin formed of the conical tip portion having a small tip angle and the columnar base portion, the sheet is slightly elevated above the base portion. Although it is possible to form an opening having an opening diameter close to the diameter of the pin if it is set so as to pierce, the pin tip becomes long and the swinging of the pin due to rotation of the roll becomes more serious. As a result, the hole once formed is scratched by the pin tip, which adversely affects the shape of the hole. Moreover, the aperture ratio is also lowered, which is very inconvenient. Furthermore, if the tip angle is small, the resistance at the initial stage of the pin sticking into the sheet decreases, so the effect of stretching the sheet is poor,
The three-dimensionality of the aperture is reduced.

On the other hand, if the tip angle of the pin is increased,
Since the pin tip is shortened, the swing of the pin due to the rotation of the roll is reduced, and the once formed hole is not scratched by the pin tip. Further, since the resistance at the initial stage when the pin is pierced into the sheet is large, the sheet is effectively stretched and a three-dimensional opening is formed. However, since the depth at which the pin pierces the sheet is not large, the diameter of the formed opening changes sensitively according to the depth of the pin piercing. As a result, especially in the case of forming an opening in a non-woven fabric, the piercing easiness of the pin varies depending on the fabric of the non-woven fabric, and the fiber density is lower at the thinner fabric, so that the piercing resistance of the pin is reduced. Is low and the pin sticks deeply. Since unevenness of the texture of the non-woven fabric is unavoidable to some extent, the diameters of the formed openings have considerable variations. Moreover, in order to obtain a large opening diameter, the sheet must be inserted deep into the pin, which causes a problem of the pin coming off. Further, if the pin is stabbed shallowly, there is also a problem that a portion with almost no holes is formed.

Therefore, an object of the present invention is to form a three-dimensional opening having a large opening diameter and a large opening ratio, and to have a structure having a structure capable of realizing effective liquid transfer from the surface layer to the back layer. An object of the present invention is to provide a method and an apparatus for manufacturing a perforated sheet.

[0010]

Means for Solving the Problems As a result of intensive studies by the present inventors, by forming a convex pin for forming an opening into a specific shape, it is possible to prevent a sheet from being pierced deeply into the convex pin. However, it has been found that a three-dimensional opening can be effectively formed.

Further, according to the present invention, there is provided a first pressing die having a large number of convex pins arranged in a row along the sheet conveying direction and the rows are arranged in multiple rows, and the convex shape. Manufacture of a three-dimensional apertured sheet having a large number of three-dimensional apertures by interposing the sheet between a concave die that fits into a pin or a second pressing die that has a protrusion that fits between the multiple rows In the way
As the convex pin, a pin formed of a pillar-shaped base portion, a cone-shaped tip portion, and a brim portion extending in a direction substantially perpendicular to the axial direction of the base portion at a substantially boundary portion between the base portion and the tip portion, A method for producing a three-dimensional apertured sheet characterized by being used, or a pin comprising a pillar-shaped base and a cone-shaped tip as the convex pin, wherein the tip is a hem. And the apex, and the pin is used in which the apex angle of the apex is larger than the intersecting angle of the extension lines of the two ridge lines facing each other in the skirt toward the apex. The above object is achieved by providing a method for producing an apertured sheet.

Further, the present invention is an apparatus preferably used for carrying out the method for producing the above-mentioned three-dimensional apertured sheet of the present invention, which has a large number of convex pins in a row and the rows are arranged in multiple rows. By interposing a sheet between the first roll that is in contact with the first roll and the second roll that has a concave shape that fits into the convex pin or a protrusion that fits between the multiple rows, a large number of three-dimensional bodies can be obtained. In an apparatus for producing a three-dimensional apertured sheet having apertures,
As the convex pin, a pin formed of a pillar-shaped base portion, a cone-shaped tip portion, and a brim portion extending in a direction substantially perpendicular to the axial direction of the base portion at a substantially boundary portion between the base portion and the tip portion, An apparatus for producing a three-dimensional apertured sheet characterized by being used, or a pin comprising a column-shaped base and a cone-shaped tip as the convex pin, wherein the tip is a hem. And the apex, and the pin is used in which the apex angle of the apex is larger than the intersecting angle of the extension lines of the two ridge lines facing each other in the skirt toward the apex. The above object is achieved by providing an apparatus for manufacturing an apertured sheet.

[0013]

In the method and apparatus for manufacturing a three-dimensional apertured sheet according to the present invention, the flange portion is provided at a substantially boundary portion between the base portion and the tip end portion of the convex pin for forming an aperture, and thus By controlling the relative position between the convex pin and the sheet provided with the holes, it is possible to form a three-dimensional hole having a stable shape even if the sheet has unevenness in the formation. Moreover, since the convex pin does not stick too much into the sheet, the amount of fitting between the convex pin and the pressing die fitted thereto can be increased. As a result, it is possible to form an opening having a more excellent three-dimensionality. Furthermore, when providing openings in the non-woven fabric, the opening diameter can be made even larger, so that the peripheral portion of the openings formed as a result,
The abundance of fibers separated by the openings increases,
The fiber density can be increased.

Further, since the tip of the convex pin has a two-step shape consisting of a hem and a top, the overall length of the convex pin is kept short, and the convex pin stuck into the sheet is It is possible to improve the removal, prevent the convex pin from re-interfering with the once formed hole, and form the hole having a stable shape. In addition, since the shape of the hole once formed is not disturbed by the convex pin, the texture of the obtained three-dimensional hole sheet does not deteriorate.

Further, since the tip angle of the apex is larger than the crossing angle of the extension lines of the two ridge lines facing each other in the skirt toward the apex (that is, it is more obtuse), The resistance at the initial stage when the convex pin pierces the sheet can be increased, and the holes are more three-dimensionally formed. Particularly when forming pores in a nonwoven fabric, the fibers between the pores are stretched to the peripheral edge of the pores, so the fiber density between the pores is reduced, and the liquid residue due to capillary force can be reduced. it can.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an apparatus preferably used in the method for producing a three-dimensional apertured sheet of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 to 10, the above-described apparatus for manufacturing a three-dimensional apertured sheet has a first roll having a large number of convex pins 20 arranged in a row and the rows being arranged in multiple rows. A sheet is interposed between 22 and a second roll 24 having a concave shape that fits into the convex pin 20 or a protrusion that fits between the multiple rows, thereby having a large number of three-dimensional openings. A three-dimensional apertured sheet is manufactured.

More specifically, the manufacturing apparatus of the present invention has a pair of rolls of the first roll 22 and the second roll 24, and the entire circumference of the surface of the first roll 22 is the above. The convex pins 20 are arranged in rows, and the rows of the convex pins 20 are arranged in multiple rows. The arrangement direction of the rows is generally parallel to the sheet conveying direction. The arrangement of the convex pins 20 is not particularly limited as long as the convex pins 20 are arranged in rows and the rows of the convex pins 20 are arranged in multiple rows. For example, as shown in FIG. As shown, they can be arranged in a staggered pattern.

The interval L between the rows (see FIG. 5 (a)) generally depends on the material and thickness of the sheet and the desired aperture ratio, but is preferably 0.5 to 20 mm. In addition, the distance M between the adjacent holes in the row (see FIG.
In general, (a) is also preferably 0.5 to 20 mm, though it depends on the material and thickness of the sheet and the target value of the porosity.

When heating the first roll 22 and / or the second roll when punching a sheet, a heating means such as a cartridge heater inserted into the rotary shaft of the roll is used. Good.

Then, the above-mentioned convex pin which is a characteristic part of the present invention will be described in detail. In the present invention, the following two types of pins are used as the convex pins. A pin comprising a pillar-shaped base portion and a cone-shaped tip portion, wherein the tip portion comprises a hem portion and a top portion, and a tip angle of the apex of the two ridge lines facing each other in the skirt portion. A pin that is larger than the intersection angle of the extension line toward the top. A pin comprising a column-shaped base portion, a cone-shaped tip portion, and a collar portion extending substantially at a right angle to the axial direction of the base portion at a substantially boundary portion between the base portion and the tip portion. Each of these two modes of pin is described in detail below.

First, the convex pin of the above aspect will be described. As shown in FIG. 1, the convex pin includes a column-shaped base portion 12 and a cone-shaped tip portion 14.

The pillar-shaped base 12 is formed by the convex pin 2
The cross-sections of the 0 perpendicular to the axial direction are substantially the same along the axial direction, and the cross-sectional shape is preferably circular, elliptical or polygonal, but is not limited to such a shape. The size of the cross section may be appropriately adjusted so as to obtain a desired aperture diameter, and is not particularly limited, but when the cross section is circular, the diameter φ is generally 0.2 to 10.
mm is preferable, 0.5 to 5 mm is more preferable, and 1 to 2 mm is even more preferable. When the cross-sectional shape is elliptical, the major axis / minor axis ratio is generally preferably 1.0 to 2.0, and more preferably 1.1 to 1.3. Also,
The major axis length is preferably 0.2 to 10 mm, and 0.
More preferably 5 to 5.0 mm, and 1 to 2 mm
Is more preferable. It is also preferable that the flow direction of the sheet at the time of providing the opening and the direction of the short axis are made to coincide with each other because the shape of the opening becomes close to a perfect circle and the appearance is improved. When the cross section is polygonal, a 2n polygon (n = n) inscribed in an ellipse having a major axis length of 0.2 to 10 mm and a major axis / minor axis ratio of 1.0 to 2.0.
It is preferably 2, 3 or 4). Further, the height z of the base portion 12 is preferably a fitting depth y + 2 mm or more as shown in FIG. 8 (a) in order to avoid thermal contact when forming the opening. The fitting depth will be described later.

As shown in FIG. 1, the tip portion 14 of the convex pin 20 is composed of a skirt portion 40 and a top portion 42.
The tip angle θ _t of the top portion 42 is set to be larger than the intersection angle θ _b of the extension lines of the two ridge lines 44 and 45 facing each other in the skirt portion 40 toward the top portion. By forming the tip portion 14 into such a shape, it becomes possible to form a three-dimensional opening while ensuring a larger opening diameter and opening rate.

The tip angle θ _t of the apex 42 is _{equal to} that of the hem 4
As described above, it is preferable that the crossing angle θ _b is greater than 0, but more specifically, the tip angle θ _t is 45.
Preferably, the crossing angle θ _{b is}
Is preferably 20 to 60 degrees. More preferably, the tip angle θ _t is 55 to 75 degrees, and the crossing angle θ _b is 30 to 45 degrees. If the tip angle θ _t is less than 45 degrees, the height of the tip portion 14 becomes high and the convex pins 20 are apt to be stuck too easily. In some cases, the effect of giving a three-dimensional effect may be poor. Further, if the tip angle θ _t exceeds 90 degrees, the sharpness of penetrating the sheet may be lost, so it is preferable to set it within the above range. On the other hand, if the intersection angle θ _b is less than 20 degrees, the resistance for pulling out the convex pin 20 from the sheet becomes large,
If the height of the tip portion 14 becomes high and the intersecting angle θ _b exceeds 60 degrees, the depth at which the convex pin 20 pierces the sheet becomes small, so that the diameter of the opening to be formed becomes convex. Since it changes sensitively according to the depth of sticking of the pin 20, it is preferable to set it within the above range.

The height b of the skirt portion 40 at the tip portion 14 depends on the roll diameter used, the pin diameter, the tip angle θ _t , and the thickness of the sheet in which the holes are to be formed, but is generally 0.8 mm to
1.5 mm is preferable. In other words, [thickness of sheet to be provided with openings] to [thickness of sheet + 0.5 mm] is preferable. If the height b is less than the [thickness of the sheet], the thickness of the sheet becomes larger than the height b of the skirt portion 42, and a large aperture diameter cannot be obtained. On the other hand, even if the height b exceeds [the thickness of the sheet + 0.5 mm],
Not only is there no significant improvement in the state of formation of the openings, but the total length of the convex pins 20 may become long, and the tip portion 14 may interfere again with the openings 6. It is preferably within the range. On the other hand, the height a of the top portion 42 at the tip portion 14 is generally
It is preferably 0.5 mm or more. If the height a is less than 0.5 mm, it may not be possible to form a hole having a stable shape. Therefore, the height a is preferably 0.5 mm or more.

In the embodiment shown in FIG. 1, the tip 1 is
4 has a so-called two-step shape consisting of the skirt portion 40 and the top portion 42, but the shape of the tip portion 14 is not limited to this mode. For example, as shown in FIG. 40 consists of a first skirt 40a connected to the base 12 and a second skirt 40b connected to the top, and two ridges 44a facing each other in the first skirt 40a,
The intersection angle θ _ba of the extension line of 45 a toward the apex and the two ridge lines 44 facing each other in the second skirt 40 b.
and the crossing angle θ _bb of the extension line of b, 45b toward the above-mentioned top direction,
Between the tip angle theta _t, convex pin such that there is θ _ba> θ _bb> θ _t the relationship is also within the scope of the present invention.

In the tip portion 14 shown in FIG. 1, the ridge lines 44 and 45 facing each other are straight lines, but the shape of the tip portion 14 is not limited to this mode. For example, the ridge line is curved. May be

Next, the convex pin of the above aspect will be described. As shown in FIG. 3A, the convex pin has a pillar-shaped base 12, a cone-shaped tip 14, and a substantially boundary between the base and the tip, which is substantially perpendicular to the axial direction of the base. And a collar portion 18 extending in the direction.

The height h of the tip portion 14 depends on the diameter of the roll to be used, the thickness of the sheet to be provided with the holes, the pin diameter, and the angle of the tip angle of the top portion 42 of the tip portion 14 which will be described later. Generally, [thickness of sheet to be provided with apertures] to
It is preferably [twice the pin diameter φ]. Above height h
If the thickness is less than the thickness of the sheet in which the holes are to be provided, the tip portion 14 may not be able to penetrate the sheet sufficiently and the hole diameter may become small, and the height h of the tip portion 14 may be twice the pin diameter φ. If it exceeds the above range, the tip portion 14 may re-interfere with the opening, so it is preferable to set it within the above range. Also,
The tip angle θ _t of the tip portion 14 is 25 to 90 °,
In particular, it is preferable that the angle is 30 to 60 ° from the viewpoint that the pin can be easily pierced into the sheet and the pin tip can be prevented from re-interfering with the opening.

In the tip portion 14 shown in FIG. 3 (a), the ridge lines 44 and 45 facing each other are straight lines, but the shape of the tip portion 14 is not limited to this mode.
For example, the ridge may be a curve.

As shown in FIGS. 3 (a) and 3 (b), the convex pin 20 extends substantially at the boundary between the base 12 and the tip 14 in a direction substantially perpendicular to the axial direction of the base 12. It has a collar part 18 formed. The convex pin 20 is the flange 18
Since the sheet is prevented from being deeply pierced into the convex pin 20 at the time of forming the aperture, the convex pin 20 can be smoothly removed from the sheet to stably form a three-dimensional aperture. You can The collar portion 18 is particularly effective when forming openings in a nonwoven fabric having large unevenness in texture.

Further, by using the collar portion 18,
Since it becomes possible to deeply fit the concave shape or the ridge portion of the second roll 24 into the convex pin 20 (that is, the fitting depth can be made large), the above-mentioned sheet among the above-mentioned sheets can be used. The recessed portion or the portion pushed in by the protruding portion and the peripheral portion thereof are extended to form an opening, and as a result, the apparent thickness of the entire three-dimensional opening sheet can be increased, and the cushioning property is enhanced. Moreover,
When the three-dimensional apertured sheet is used as, for example, a surface sheet of an absorbent article, the liquid absorbed by the absorber is prevented from returning.

In particular, when a nonwoven fabric is used as the sheet, the fibers between the openings are stretched, so that the fiber density between the openings is reduced (the distance between the fibers is large) and the capillary force is reduced. Moreover, the shape between the openings is arched, and the sheet becomes more three-dimensional. Therefore, when the above-mentioned three-dimensional apertured sheet is used as a surface sheet of an absorbent article, for example, the liquid absorbed in the absorber is prevented from reversing, the contact area with the skin is reduced, and the dry feeling is further improved. To do. Further, since it is possible to increase the diameter of the aperture, the amount of fibers divided by the peripheral edge of the lower end of the aperture by the convex pin 20 increases, and as a result, the fiber density of the peripheral edge of the lower end of the aperture increases. As a result, an extremely large gradient occurs in the fiber density between the openings and between the lower ends of the openings.
In this way, a part that has appropriate softness and softness (a part with a small fiber density) and a rigid part (a part with a large fiber density) that is not crushed by pressure coexist in one sheet, and the entire sheet has a suitable size. Cushioning is realized. Further, since the presence of the rigid portion maintains a constant thickness even when the three-dimensional apertured sheet is crushed by pressure, the three-dimensional apertured sheet is used as a surface sheet of an absorbent article, for example. In this case, the liquid absorbed by the absorber is prevented from returning.

Furthermore, since the fibers are densely present in the portion where the fiber density is high (mainly, the peripheral portion of the lower end of the opening),
When the three-dimensional apertured sheet is used as, for example, a surface sheet of an absorbent article, the liquid existing on the surface of the three-dimensional apertured sheet is quickly sucked by the capillary force and guided to the absorber.
On the other hand, in the portion where the fiber density is low (mainly, the arch-shaped portion between the openings), the fibers are sparsely present and the capillary force is weak, and as a result, the liquid once absorbed by the absorber is It becomes difficult to return to the surface of the three-dimensional apertured sheet. As described above, since the three-dimensional apertured sheet manufactured according to the present invention has a dense structure with respect to the density of fibers, a gradient of the capillary force is generated in a single structure. When used for the surface sheet of No. 3, the liquid residue on the surface is reduced, and an absorbent article having a further improved dry feeling can be obtained.

As shown in FIGS. 4 (a) to 4 (c), it is preferable that the collar portion 18 be present over the entire side surface of the base portion 12, but this is not essential in the present invention. . However, the collar portion 18 is preferably provided over 1/4 of the entire circumference of the side surface of the base portion 12, and more preferably over 1/2 or more. If the portion where the collar portion 18 is provided is less than 1/4, the portion other than the collar portion 18 may stick deeply into the base portion of the convex pin 20, which is not preferable. Further, in this case, the collar portion 18 is
It may be provided continuously or intermittently over 1/4 or more of the entire side surface circumference of the base portion 12 as shown in FIGS. 4 (d) and 4 (e).

It is also preferable that the collar portion 18 is provided point-symmetrically with respect to the central axis of the convex pin 20, as shown in FIG. 3 (b). Further, as shown in FIG. 5B, it is also preferable that the collar portion 18 is provided only in the sheet conveying direction. As described above, by providing the collar portion 18 only in the sheet conveying direction, it is possible to reduce the distance between the holes in the direction perpendicular to the sheet conveying direction and to increase the aperture ratio, which is preferable.

The collar portion 18 does not need to extend completely in the direction perpendicular to the axial direction of the base portion 12, but in short,
It suffices that the sheet is extended at an angle that can prevent the sheet from being deeply stuck in the root direction of the convex pin 20 (see, for example, FIG. 6A). Therefore, there is no limitation on the shape or thickness of the lower surface of the collar portion 18. For example, as shown in FIGS. 6B and 6C, the case where the lower surface of the collar portion 18 extends to the root of the convex pin 20 to form a pillar is also within the scope of the present invention. However, in general, the thickness of the collar portion 18 is preferably 0.3 to 2 mm,
More preferably, it is 0.5 to 1.5 mm. If the thickness of the collar portion 18 is less than 0.3 mm, the collar portion 18
Cannot maintain its rigidity, or the side surface of the collar portion 18 becomes thin, and fibers or the like forming the sheet may be caught in the collar portion 18 and disturb the sheet. If it exceeds 2 mm, the sheet and the collar portion 18 are The contact area with the side surface becomes large, and heat may spread to the vicinity of the skin contact area of the sheet to deteriorate the touch, so that it is preferably within the above range.

The collar portion 18 is provided at a substantially boundary portion between the base portion 12 and the tip portion 14. More specifically, the upper surface of the collar portion 18 is 0.5 mm from the upper end of the base portion 12.
It is preferable that the upper surface of the collar portion 18 is within 0.1 mm from the upper end of the base portion 12, and it is more preferable that the upper surface of the collar portion 18 is within the position of 0.1 mm or less, as shown in FIG. The upper surface is located at the upper end of the base 12.

Further, the extension width (overhang width) of the collar portion 18
Is preferably 0.05 mm or more at the widest portion, and more preferably 0.10 mm or more. If the extension width is less than 0.05 mm, the effect of providing the collar portion 18 may not be sufficiently exhibited, which is not preferable.

The convex pin of the above aspect is preferably
The features of the convex pin of the above aspect are included. That is, the tip portion 14 of the convex pin 20 is composed of a skirt portion 40 and a top portion 42, as shown in FIGS.
The tip angle θ _t of the top portion 42 is set to be larger than the intersection angle θ _b of the extension lines of the two ridge lines 44 and 45 facing each other in the skirt portion 40 toward the top portion.

Further, regarding the points not particularly described in detail regarding the convex pin of the above-mentioned aspect, the detailed explanations regarding the convex pin of the above-mentioned aspect are appropriately applied.

It should be noted that what has not been described in detail with respect to the first roll, such as the method of assembling the first roll, is described in JP-A-6-330443.
The description in columns 44, line 5 to column 5, line 28, column 6, lines 28-40, and FIGS. 2 to 4 can be appropriately applied.

Next, the second roll 24 used as a pair with the first roll 22 will be described. On the surface of the second roll 24, a concave die into which the convex pin 20 arranged on the entire circumference of the surface of the first roll is fitted is arranged, or in the row of the convex pins 20. It has a ridge that fits in between.

The concave type may be used without any particular limitation as long as it has a shape into which the convex pin 20 is fitted. As an example of such a concave type, Japanese Patent Laid-Open No. 62-62
The socket or the hole roll as described in FIG. 12 of -125061 gazette is mentioned.

Further, as shown in FIG. 8, the protrusions are fitted between the rows of the convex pins 20. The distance d between the protrusions 26 is determined in consideration of the diameter φ of the convex pin 20 and the thickness of the sheet 4 in the sheet conveying direction. Generally, the difference between the distance d and the pin diameter φ (d−
φ) is preferably 0.05 to 4 mm, and 0.1
It is more preferable that the distance is ˜1 mm (the sheet conveying direction in FIG. 8 is a direction perpendicular to the paper surface). The thickness t of the protrusion 26 in the sheet conveying direction is
It is desirable that the convex pin 20 is thin against the above-mentioned condition so that it is thin, but considering the strength, 0.1-1 m
It is desirable that it is m. The sheet is not shown in FIG.

Further, as shown in FIG. 8, the insertion depth y between the first roll 22 and the second roll 24 is 0.2.
-3.0 mm is preferable, and 0.6-1.8 m
More preferably m.

When the convex pin 20 is fitted into the concave shape or the protruding portion, the gap between the convex pin 20 and the concave shape or the protruding portion also depends on the thickness of the sheet 4 to be opened. However, in general, it is preferably 0.1 to 2 mm.

Incidentally, points which have not been described in detail with respect to the second roll 24, for example, the assembling method of the second roll and the like are described in JP-A-6-330443, column 5, lines 29 to 39. The description of FIGS. 5 and 6 and the like can be applied as appropriate.

Next, the method for producing the three-dimensional apertured nonwoven fabric of the present invention will be described. The method for producing a three-dimensional apertured nonwoven fabric of the present invention includes a first pressing die having a large number of convex pins in a row along the sheet conveying direction and the rows being arranged in multiple rows.
A three-dimensional aperture having a large number of three-dimensional apertures by interposing the sheet between the concave die that is inserted into the convex pin or the second pressing die that has a ridge portion that is inserted between the multiple rows. In the method for producing a sheet, as the convex pin, a pillar-shaped base portion, a cone-shaped tip portion, and a portion extending substantially perpendicular to the axial direction of the base portion at a substantially boundary portion between the base portion and the tip portion. Characterized in that a convex pin consisting of a collar part is used, or as the convex pin, a pin consisting of a pillar-shaped base and a cone-shaped tip,
The pin is used in which the tip portion is composed of a skirt portion and a top portion, and the tip angle of the top portion is larger than the intersection angle of extension lines of two ridge lines facing each other in the skirt portion toward the top portion. It is characterized by that.

More specifically, as shown in FIG. 9 showing one embodiment of the method of the present invention, the sheet 4 to be perforated is supplied from the supply roll 32, and the sheet 4 passes through the position regulating device 33. Then, the sheet 4 is conveyed to the roll unit 34 including the first roll 22 as the first pressing die and the second roll 22 as the second pressing die in a state where there is no lateral shake. It The first roll 22 has a plurality of rows of the convex pins 20 arranged side by side. On the other hand, the second roll 24 is configured such that each of the convex pins 20
It has a concave shape to be fitted into or a ridge portion to be fitted between the rows of the convex pins 20. The first roll 2
2 and the second roll 24 rotate synchronously, and by interposing the sheet 4 between both rolls 22 and 24, the convex pin 20 punches the sheet 4 to form the sheet 4. A large number of three-dimensional openings (not shown) are formed. Then, the roll unit 34 is configured so as to be supplied to the next process via a position regulating device 37 in the subsequent stage.

Next, in the method of the present invention, the process of forming the above-mentioned openings will be described in detail with reference to FIG. Figure 10
As shown in FIG. 5, the sheet 4 is inserted between the first roll 22 and the second roll 24 (not shown) that rotate in synchronization with each other in accordance with the rotation of both rolls. The sheet 4 comes into contact with the concave or ridge portion of the second roll 24 at the position A in FIG. Next, the convex pin 20 pierces the sheet 4 at the position B in FIG. As the rolls 22 and 24 rotate, the convex pin 20 gradually pierces the sheet 4, but since the flange portion 18 provided on the convex pin 20 acts as a stopper for the sheet 4, The collar 18
The convex pin 20 is deeper than the position where the
Is prevented from sticking to the sheet 4 (position C in FIG. 10). In addition, the tip portion 14 has the top portion 42.
And the skirt portion 40 are in two stages, it is possible to prevent the tip portion 14 from re-interfering with the formed opening.
Next, the convex pin 20 is removed from the sheet 4 at the position D in FIG. As a result, the three-dimensional apertured sheet 2 in which a large number of three-dimensional apertures 6 are formed is obtained.

More specifically, due to the action of the collar portion 18, the sticking of the convex pin 20 into the sheet 4 is limited, and FIG. 11A which is an enlarged view of FIG. 10 and its sectional view in the flow direction. As shown in FIG. 11B, the convex pin 20 sticks into the sheet 4 up to the tip portion 14 thereof. On the other hand, the protruding portion 26 of the second roll
Fit deeply into the seat 4. As a result, a perforated sheet having extremely high three-dimensionality (that is, a large thickness) can be obtained.

When the sheet 4 is provided with three-dimensional holes, the sheet 4 may be perforated at room temperature, but preferably the first roll 22 or the first roll 22 and the second roll. Both 24, for example, 60-26
The sheet 4 is perforated by heating to 0 ° C. As a result, the lower end peripheral portion of the opening can be softened and melted, and the lower end peripheral portion can be formed harder than the other portions of the sheet, so that the three-dimensional shape of the opening can be formed more effectively. Such heating is particularly effective when forming openings in the nonwoven fabric. It is also preferable to preheat the sheet 4 or cool it after opening the holes.

The sheet 4 is not particularly limited in its material as long as it has a sheet shape and can be pierced by the convex pin 20. For example, a thermoplastic film or sheet can be used, but it is particularly preferable to use a non-woven sheet that is preferably used as a surface sheet of an absorbent article. In addition, it is also preferable to use various sheets obtained by combining non-woven fabrics, non-woven fabrics and films, non-woven fabrics and papers, or non-woven fabrics and other sheet materials.

In FIG. 9 showing one step of the method of the present invention, the first roll 22 is the second roll 2 described above.
4 is shown below, the positional relationship may be upside down. Further, the first roll 22 and the second roll 24 are not limited to a mode in which they are used as a pair, and for example, as shown in FIG. 14 of JP-A-62-125061, a plurality of first rolls is used. It is also possible to use one second roll for each roll.

Next, the present invention will be described in more detail with reference to the following examples, but it goes without saying that the present invention is not limited to such examples.

Example 1 A core-sheath type PET / PE composite fiber (volume ratio 50/50) having a fiber diameter of 2 denier was opened by a card machine, and then the fibers were fused by hot air,
Suction heat bond non-woven fabric (basis weight 25g / m ² ,
(Appearance thickness under 0.5g / cm ² load is about 0.8mm)
Was manufactured.

The convex pin (base) shown in FIGS. 7 (a) and 7 (b) is
Part pin diameter: 1.5 mm, hem 44 height b: 1.00
mm, height a of the top 42: 0.99 mm, θ_t: 60
Degree, θ _b: 37 degree) is a table of a roll having a diameter of about 150 mm.
The first roll arranged in multiple rows over the entire circumference of the surface, and
Using a second roll having a ridge portion fitted between rows
By forming three-dimensional holes in the above-mentioned nonwoven fabric, three-dimensional hole sheet
Was manufactured. In the first roll, the sheet
The pitch between the rows in the transport direction of is 2.2 mm.
The convex protrusion in the direction perpendicular to the sheet transport direction.
The pitch between the holes was 2.5 mm. Also, the aperture is
The heating was performed by heating the first roll to 125 ° C.

Table 1 shows various characteristics of the three-dimensional apertured sheet thus obtained. In Table 1, the porosity was measured by using the image analysis device “Excel” manufactured by Nippon Avionics Co., Ltd., and the image of the three-dimensional perforated sheet previously pasted on the black mount was input to obtain the black-and-white area ratio on the screen. The calculated area was defined as the open area ratio (%) based on the total black area. The apparent thickness is the KES compression tester (Kato Tech Co., Ltd.).
KES FB-3) was used to perform a compression test up to 50 g / cm ² in a normal test mode on the above-described three-dimensional apertured sheet, and the thickness (m) under a load of 0.5 g / cm ²
m).

Example 2 Shown in FIGS. 7 (a) and 7 (b)
Instead of the convex pin, the convex pin shown in FIGS.
(Pin diameter of the base: 1.5 mm, height of the tip 14 h:
2.25 mm, θ _t: 37 degrees) Example 1 except that
A three-dimensional apertured sheet was manufactured by the same operation as described above. This
Table 1 shows the characteristics of the three-dimensional apertured sheet obtained as
Show.

[Embodiment 3] Instead of the convex pins shown in FIGS. 7A and 7B, the convex pins shown in FIG. 1 (pin diameter of the base portion: 1.5 mm, height b of the hem portion 44). : 1.00 mm, height a of the top portion 42: 0.99 mm, θ _t : 60 degrees, θ _b :
A three-dimensional apertured sheet was produced by the same operation as in Example 1 except that (37 degrees) was used. Table 1 shows various properties of the three-dimensional apertured sheet thus obtained.

Comparative Example 1 In place of the convex pin shown in FIGS. 7A and 7B, a convex pin shown in FIG. 12 (pin diameter of base: 1.5 mm, θ _t : 37 degrees) was used. A perforated sheet was produced by the same operation as in Example 1 except that the sheet was used. Various properties of the apertured sheet thus obtained are shown in Table 1.

[0064]

[Table 1]

As is clear from the results shown in Table 1, the three-dimensional apertured sheets (Examples 1 to 3) produced by using the method and apparatus of the present invention have a high aperture ratio and a large apparent thickness. there were. Moreover, the texture was excellent. Particularly, in the three-dimensional apertured sheet (Example 1) in which the aperture is formed by using the convex pin having the flange portion and the tip portion including the top portion and the hem portion, the shape and the aperture diameter of the formed apertures. Was extremely uniform over the entire area of the sheet.

On the other hand, in the perforated sheet (comparative example 1) in which the perforations are formed by using the conventionally used ordinary convex pins, the high perforation rate cannot be achieved and the apparent thickness is small. Met. In addition, there were large variations in the shape and diameter of the formed holes.

[0067]

According to the present invention, it is possible to obtain a three-dimensional apertured sheet having an aperture diameter that maximizes the pin diameter of the convex pin and achieving a high aperture ratio. Moreover, in such a three-dimensional apertured sheet, the three-dimensionality of the formed apertures is extremely high, and moreover, there is an extremely large fiber density gradient from between the apertures to the lower peripheral edge portion of the apertures. . Therefore, the three-dimensional apertured sheet manufactured according to the present invention is particularly suitable as a surface sheet for absorbent articles such as sanitary napkins and disposable diapers.

[Brief description of drawings]

FIG. 1 is a side view showing an aspect of a convex pin.

FIG. 2 is a side view showing another aspect of the convex pin.

3 (a) is a side view showing another aspect of the convex pin, and FIG. 3 (b) is a plan view of the convex pin shown in FIG. 3 (a).

4 (a) and 4 (b) are respectively a plan view and a side view showing one aspect of a collar portion, and FIGS. 4 (c) to 4 (e).
[Fig. 6] is a side view showing another aspect of the collar portion.

5 (a) is a plan view showing an array of convex pins, and FIG. 5 (b) is a side view of the convex pins shown in FIG. 5 (a).

FIG. 6 (a) is a side view showing another aspect of the collar portion, and FIGS. 6 (b) and 6 (c) are a plan view and a side view showing another aspect of the collar portion, respectively. is there.

7 (a) and 7 (b) are respectively a plan view and a side view showing still another mode of the convex pin.

FIG. 8 is a view showing a fitted state of a first roll and a second roll.

FIG. 9 is a schematic view showing one embodiment of the method of the present invention.

FIG. 10 is a schematic view showing a process of forming an opening in the method of the present invention.

11 (a) is a partially enlarged view of FIG. 10, and FIG. 11 (b) is a sectional view in the flow direction of FIG. 11 (a).

FIG. 12 is a side view showing a conventional convex pin.

[Explanation of symbols]

 2 three-dimensional hole sheet 4 four sheet 6 three-dimensional hole 12 base portion 14 tip portion 18 collar portion 20 convex pin 22 first roll 24 second roll 26 ridge 40 hem portion 42 top portion 44, 45 ridgeline

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasuhiro Komori 2606 Akabane, Kai Town, Haga-gun, Tochigi Prefecture Kao Co., Ltd. Tochigi Research Laboratory

Claims (9)

[Claims] 1. A first pressing die having a large number of convex pins arranged in a row along the sheet conveying direction, and the rows are arranged in multiple rows, and fitted into the convex pins. A method for producing a three-dimensional apertured sheet having a large number of three-dimensional apertures by interposing the sheet between a concave die or a second pressing die having a ridge portion fitted between the multiple rows, As the convex pin, a pin formed of a pillar-shaped base portion, a cone-shaped tip portion, and a brim portion extending in a direction substantially perpendicular to the axial direction of the base portion at a substantially boundary portion between the base portion and the tip portion, A method for producing a three-dimensional apertured sheet characterized by being used. 2. The tip portion comprises a hem portion and a top portion,
The method according to claim 1, wherein a tip angle of the apex is larger than a crossing angle of extension lines of two opposing ridgelines in the skirt toward the apex. 3. The method of claim 2, wherein the tip angle is 45 to 90 degrees and the crossing angle is 20 to 60 degrees. 4. The method according to claim 1, wherein the collar portion is provided over ¼ or more of the entire circumference of the base portion. 5. The method according to claim 1, wherein the collar portion is provided only in the front-rear direction of the sheet conveying direction. 6. A first roll having a large number of convex pins arranged in a row and the rows being arranged in multiple rows, and a concave die fitted into the convex pins or fitted between the multiple rows. Second having a protruding portion
In the device for producing a three-dimensionally open sheet having a large number of three-dimensional holes by interposing a sheet between the roll and the roll, the convex pin is composed of a pillar-shaped base and a cone-shaped tip. The pin, wherein the tip portion is composed of a skirt portion and a top portion, and the tip angle of the top portion is larger than the intersection angle of extension lines of two ridge lines facing each other in the skirt portion in the top direction. An apparatus for manufacturing a three-dimensional apertured sheet characterized by using pins. 7. A first pressing die having a large number of convex pins arranged in a row along the sheet conveying direction, and the rows are arranged in multiple rows, and fitted into the convex pins. A method for producing a three-dimensional apertured sheet having a large number of three-dimensional apertures by interposing the sheet between a concave die or a second pressing die having a ridge portion fitted between the multiple rows, The convex pin is a pin having a columnar base and a cone-shaped tip, the tip having a hem and a top, and the tip angle of the apex facing each other at the hem. A method for producing a three-dimensional apertured sheet, characterized in that the above-mentioned pin is used which is larger than a crossing angle of extension lines of two ridge lines toward the top. 8. The method of claim 7, wherein the tip angle is 45 to 90 degrees and the crossing angle is 20 to 60 degrees. 9. A first roll having a large number of convex pins arranged in a row, and the rows being arranged in multiple rows, and a concave type fitted into the convex pins or a fitting between the multiple rows. Second having a protruding portion
In the apparatus for producing a three-dimensional hole sheet having a large number of three-dimensional holes by interposing a sheet between the roll and the roll, a pillar-shaped base portion, a cone-shaped tip portion, and An apparatus for manufacturing a three-dimensional apertured sheet, characterized in that a pin formed of a flange portion extending substantially at a right angle to the axial direction of the base portion is used at a substantially boundary portion between the base portion and the tip end portion.