JP6052747B1 - Absorbent article having stretchable region - Google Patents

Abstract

An absorbent article having an expansion / contraction region in which an expansion / contraction stress differs depending on the position in the region of the expansion / contraction region. An absorbent article including an elastic sheet, wherein the elastic sheet is elastic at least in the front-rear direction between a first sheet layer having no elasticity and a second sheet layer. Films are laminated, and the first sheet layer and the second sheet layer are joined directly or via an elastic film at a number of joints spaced apart, and the stretchable sheet is The elastic film contracts due to the contraction force of the elastic film and can be expanded by applying an external force in the front-rear direction. Due to the difference between the two side regions, the stretching stress in the front-rear direction is different between the width directions. [Selection] Figure 13

Description

  The present invention relates to an absorbent article having a stretchable region, typically a disposable diaper, provided with a stretchable sheet in which a first sheet layer and a second sheet layer sandwich an elastic film.

  In an absorbent article, for example, a disposable diaper, in order to improve fit to the body surface, it is common to impart stretchability to appropriate places such as around the legs and around the trunk. As a method for imparting stretchability, conventionally, a method of fixing an elongated elastic member such as rubber thread in a state of being stretched in the longitudinal direction has been widely adopted. However, when it is desired to impart stretchability to a certain width. Has adopted a mode in which the rubber thread is fixed in a state of being arranged side by side at intervals in the width direction.

  On the other hand, in place of a plurality of thread rubbers arranged in parallel, it has been proposed to use a nonwoven fabric / elastomer film / nonwoven fabric as a material that presses against a surface strip to give stretchability and takes the touch into consideration. (For example, refer to Patent Document 1).

  However, in Patent Document 1, an elastic film that expands and contracts in a continuous MD direction having a higher melting point or no melting point is supplied between the first outer layer and the second outer layer, and the first outer layer at a predetermined position. And a second outer layer are directly bonded by welding, and then a pulling force is applied to the CD direction to form a through hole penetrating the first outer layer, the elastic film, and the entire second outer layer at the bonding site. is there.

Since the stretchable sheet according to Patent Document 1 is intended for continuous production, the pattern of the raised portions in the heat bonding roller forming the joint is uniform in the width direction and the circumferential direction. Even if the position in the width direction is different, the stretching stress is uniform.
Therefore, it cannot be said that this stretchable sheet has a wide range of uses.

Japanese Patent No. 4562391

  Then, the main subject of this invention is providing the absorbent article which has an expansion-contraction area | region from which expansion-contraction stress differs according to a position in the area | region of an expansion-contraction area | region.

  The present invention that has solved the above problems is as follows.

(Basic form)
The absorbent article of the present invention is provided with a stretchable sheet that can be stretched in the front-rear direction.
In the stretchable sheet, an elastic film that is stretchable in the front-rear direction is laminated between a first sheet layer made of, for example, a non-woven fabric that does not have stretchability, and a second sheet layer, made of, for example, a non-woven fabric that does not have stretchability. In addition, the first sheet layer and the second sheet layer are joined at a large number of joints that are spaced apart, either directly or via an elastic film.
The stretchable sheet contracts due to the contraction force of the elastic film, and can expand when an external force is applied in the front-rear direction.
In the region of the stretchable sheet, the joint area ratio occupied by the total area of the joints included in the unit area is different between the intermediate region and the both side regions in the width direction of the stretchable sheet. The stretching stress in the front-rear direction is different between them.

  In the present invention, the arrangement pattern of the joints is not limited. One example is a staggered arrangement that exhibits a good appearance.

Disposable diapers, particularly tape-type disposable diapers, are fixed around the waist with tape, and generally are not provided with a member that fits the entire front and back bodies.
That is, because it does not follow the movement of the waist well, when the wearer gets up or bends, the front and back of the diaper may be lifted (separated) from the body surface, or may be displaced in the front-rear direction. , So-called leakage before and after.
However, in the absorbent article according to the present invention, for example, a tape-type disposable diaper, the wearer is provided with a stretchable sheet that is stretchable at least in the front-rear direction and has a stretchable region at least in the intermediate region in the width direction. When the body pressure by the wearer is moved in the front-rear direction of the intermediate region when getting up or bent, the intermediate region of the tape-type disposable diaper expands and contracts in the front-rear direction, so that the front and rear are lifted (separated) from the body surface Alternatively, it is possible to prevent the wearer from shifting in the front-rear direction, and to suppress front-rear leakage. Furthermore, especially when the stretchable sheet constitutes the outer shape sheet, since the stretchable region is formed in the intermediate region in the width direction, wrinkles or irregularities are formed by contraction in the front-rear direction, so when the wearer of the diaper gets up from the supine state, Since it has a non-slip function, it has the advantage of preventing longitudinal displacement.

  Another aspect of the absorbent article of the present invention is that, in the region of the stretchable region, the joint area ratio occupied by the total area of the joints included in the unit area is the intermediate region and both sides in the width direction of the stretchable sheet. It is an absorbent article in which the stretching stress in the front-rear direction is different between the width directions by being different in the region and also in the intermediate region.

Another aspect of the absorbent article of the present invention is capable of stretching at least in the front-rear direction, the first stretchable region in the front-rear direction intermediate region of the widthwise intermediate region, and the second stretchable in the front-rear direction of the front-rear direction intermediate region. An absorbent article comprising a stretchable sheet having a region,
In the stretchable sheet, an elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that does not have stretchability and the second sheet layer, and the first sheet layer and the first sheet layer 2 sheet layers are joined at a large number of spaced joints, either directly or via an elastic film,
The stretchable sheet contracts due to the contraction force of the elastic film, and is extensible when an external force is applied in the front-rear direction.
The joint area ratio occupied by the total area of the joints included in the unit area is different in the front-rear direction intermediate region and both side regions of the width-direction intermediate region of the stretchable sheet, so that the front-rear direction between the width directions In addition, the absorbent article has a configuration in which the stretching stress in the front-rear direction is different due to the difference in stretching stress between the front-rear direction intermediate region and the front-rear region.

A further different aspect of the absorbent article of the present invention is an absorbent article that includes an elastic sheet that can be expanded and contracted in the front-rear direction and the width direction, and that has at least an elastic region in the intermediate region in the width direction of the elastic sheet,
In the stretchable sheet, an elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that does not have stretchability and the second sheet layer, and the first sheet layer and the first sheet layer 2 sheet layers are joined at a large number of spaced joints, either directly or via an elastic film,
The stretchable sheet contracts due to the contraction force of the elastic film, and is extensible when an external force is applied in the front-rear direction.
The joint area ratio occupied by the total area of the joints included in the unit area is different between the intermediate region and both side regions in the width direction, so that the stretching stress in the front-rear direction is different between the width directions. It is an absorptive article of the composition which is.

The expansion / contraction of the expansion / contraction region that can be expanded / contracted not only in the front / rear direction but also in the width direction contributes to improving the fit around the waist or around the waist particularly in the case of a diaper.
In this case, it is desirable that the stretching stress in the front-rear direction is larger than the stretching stress in the width direction.

  In the stretchable sheet of the present invention, no hole penetrating the first sheet layer and the second sheet layer is formed. This point is different from the stretchable sheet shown in FIG. 5 or 7 of Japanese Patent No. 4562391.

In the junction part of the expansion-contraction area | region of this invention, there exists the following joining form example, for example.
(1) A form in which the first sheet layer and the second sheet layer are partially melted and joined to the elastic film, that is, the first sheet layer and the second sheet layer are joined via the elastic film.
(2) A mode in which the elastic film melts and moves into the first sheet layer and the second sheet layer, and the first sheet layer and the second sheet layer are directly joined without interposing the elastic film.
(3) It is an intermediate form between the form of (1) and the form of (2), and both surface portions of the elastic film melt and move into the first sheet layer and the second sheet layer, but elastic A form in which the first sheet layer and the second sheet layer are bonded via the remaining elastic film by partially remaining the film.

Among these forms, in particular, in the form (2) and the form (3), the difference in elastic film strength occurs between the joined part and the non-joined part. Therefore, after the stretched state of the stretch sheet holding the extension is once released and contracted to obtain a product; or after the stretch sheet holding the stretch is combined with another member, the stretched state is once released and contracted. When the product is stretched mechanically or manually in the expansion / contraction direction, breakage occurs at the boundary between the joined portion and the non-joined portion.
As a result, a through hole is formed.

In such a case, the absorbent article includes an elastic sheet that can be stretched at least in the front-rear direction and has a stretchable region at least in the intermediate region in the width direction. In the stretchable region, the stretchable sheet has stretchability. An elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that is not stretched and the second sheet layer that is not stretchable, and the first sheet layer and the second sheet layer are In other words, a large number of joints spaced apart are joined and formed through through holes formed in the elastic film.
In the case where the through hole is formed, there is an advantage that air permeability is ensured. The through holes do not need to be formed in all the joints, and exhibit air permeability even if formed in some of the joints. When the elastic film can be expanded and contracted only in the front-rear direction, the through hole has a shape extending in the front-rear direction from the edge of the joint. When the elastic film can be expanded and contracted in both the front-rear direction or the MD direction and the direction perpendicular to the MD direction (for example, the CD direction), the through hole has a shape extending in both directions from the edge of the joint, and in some cases around the joint May have an annular shape.

As described above, the elastic film of the present invention can be stretched in the front-rear direction (for example, the MD direction), and can be stretched in the front-rear direction and the orthogonal direction (for example, the CD direction).
In the latter case, the following form is obtained.
It is an absorbent article that is stretchable in the front-rear direction and the width direction, and has a stretchable region at least in the widthwise intermediate region,
In the stretchable sheet, an elastic film stretchable in the front-rear direction and the width direction is laminated between a first sheet layer that does not have stretchability and a second sheet layer that does not have stretchability, and The first sheet layer and the second sheet layer are formed by being joined through through holes formed in the elastic film, with a large number of spaced joints.
The stretchable region is contracted by the contraction force of the elastic film, and can be expanded by applying an external force in the front-rear direction.
The joint area ratio occupied by the total area of the joints included in the unit area is different between the intermediate region and both side regions in the width direction, so that the stretching stress in the front-rear direction is different between the width directions. An absorbent article characterized by having

  The joint is provided with a configuration in which the length in the orthogonal direction (width direction: CD direction) is longer than the length in the front-rear direction.

The stretchable sheet that can be stretched in the front-rear direction can be manufactured, for example, by the following method.
A supply step of interposing an elastic film stretchable in at least one direction (front-rear direction of the product) in a stretched state between the first sheet layer not stretchable and the second sheet layer not stretchable;
In this supplying step, the elastic film is interposed between the first sheet layer and the second sheet layer, and is spaced from the outside of the first sheet layer and the second sheet layer by a heat melting device. The elastic film is provided with heat melting energy by a large number of heat melting portions opened to melt the elastic film, and the first sheet layer and the second sheet layer can be directly connected to the elastic film through the elastic film. Joining process of joining with,
Including
In the joining step, the stretchable region is formed in which no hole is formed in the entire joint region and the first sheet layer and the second sheet layer remain.

  The elastic film is passed through a nip roll step in which a pair of opposing nips are arranged in the front-rear direction, and the elastic speed is increased by increasing the peripheral speed of the front nip roll step relative to the peripheral speed of the rear nip roll step between the front and rear nip roll steps. A method is provided for feeding a film to the feeding step in a stretched state. Another method may be to pass only a pair of nip rolls while winding the elastic film around the drive roll in, for example, an S shape.

The heat melting apparatus has an anvil roll and an ultrasonic horn, and the anvil roll has a plurality of protrusions formed on the outer surface thereof spaced apart in the roll length direction and the outer peripheral direction. The aspect which comprises the said thermal fusion part with an ultrasonic horn is provided.
Instead of the ultrasonic heat melting apparatus, other heat melting means may be used.

The melting point of the elastic film is lower than the melting point of the first sheet layer made of nonwoven fabric and the melting point of the second sheet layer made of nonwoven fabric, higher than this melting point, and lower than the melting points of the first sheet layer and the second sheet layer. When the melting energy corresponding to the temperature is applied, the elastic film is melted by heat, while the first sheet layer and the second sheet layer are not melted at all or are partially melted. As a result, holes are formed in the entire joint region. The first sheet layer and the second sheet layer remain.
However, the line speed at the time of manufacturing the elastic sheet is high. Therefore, even if a melting energy corresponding to a temperature higher than the melting point of the first sheet layer and the second sheet layer is given, the first sheet layer and the second sheet layer are not melted at all or are partially melted. A form in which no hole is formed can be obtained.

From such a viewpoint, the melting point of the elastic film is preferably about 80 to 145 ° C, the melting point of the first sheet layer and the second sheet layer is about 85 to 190 ° C, particularly preferably about 130 to 190 ° C, The difference between the melting points of the first sheet layer and the second sheet layer and the melting point of the elastic film 30 exhibiting a lower melting point is preferably about 50 to 80 ° C.
As a suitable specific example, the melting point of the elastic film is 95 to 125 ° C., the melting point of the first sheet layer is more than 125 ° C. to 160 ° C., more preferably 130 to 160 ° C., and the melting point of the second sheet layer is 125. More than ℃ ~ 160 ℃, more preferably 130-160 ℃.

As a preferred example of the joint portion, the area of the joint portion in the stretchable region is 0.14 to 3.5 mm ² , and the area of the opening of the through hole in the natural length state is 1 to 1 of the area of the joint portion. And the area ratio of the joint in the stretchable region is 1.8 to 22.5%.
Here, the “area ratio” means the ratio of the target portion to the unit area, and the total area of the target portion (for example, joints and openings of through holes) in the target region (for example, the stretchable region) is the area of the target region. In particular, the “joint area ratio” means the area ratio in a state of being stretched to the elastic limit in the stretching direction. In addition, the area of the opening of the through hole means a value in a state in which the stretchable structure is in a natural length, and the area of the opening of the through hole is not uniform in the thickness direction, such as different between the front and back of the elastic film. Means the minimum value.
The joint area ratio in the present specification can be selected by selecting the size, shape, separation interval, arrangement pattern in the roll length direction and roll circumferential direction, etc. of the protrusions of the anvil roll described later.

“Elongation stress” is measured by a tensile test according to JIS K7127: 1999 “Plastics—Test method for tensile properties—” with an initial chuck interval (distance between marked lines) of 50 mm and a tensile speed of 300 mm / min. It means “stress when stretched to 50% of elastic limit (N / 35 mm)”. When a test piece having a width of 35 mm cannot be cut out, the test piece is created with a width that can be cut out, and the measured value is set to a value converted into a width of 35 mm.
If the target area is small and sufficient specimens cannot be collected, a comparatively small specimen can be compared at least if it is a comparison of stretching stress.
Moreover, since a plurality of extensional stresses are different in the region, how to collect the test piece becomes a problem. Therefore, apart from obtaining the absolute value of the stretching stress, for comparison of the stretching stress, a test piece is collected for each part of the stretchable sheet, and each test piece is 150% from the 100% length in the natural state. It is also possible to compare the magnitude by the stress when stretched to% length.

  As described above, according to the present invention, it is possible to expand and contract in the front-rear direction, and have an expansion / contraction region in the intermediate region in the width direction of the expansion / contraction sheet. A sex product can be obtained. As a result, the followability to the wearer's movement is improved, and effects such as prevention of leakage are exhibited.

It is a top view of the example of arrangement pattern of a joined part. It is a schematic plan view of the example from which a junction area ratio differs. It is a schematic plan view of the other example from which a junction area ratio differs. It is a schematic plan view of another example from which a junction area ratio differs. It is sectional drawing for description before joining of an elastic sheet. It is sectional drawing for description of the joining state of an elastic sheet. It is sectional drawing for description of the contracted state of an elastic sheet. It is sectional drawing for description of the joining state of the expansion-contraction sheet | seat in which a through-hole is formed. It is a schematic diagram of the example of joining means. It is a top view for description of the example of formation of a through hole. It is a top view for description of the formation example of the through-hole which differs in an aspect. It is a top view for description of the example of formation of a through hole. It is an expanded state outline top view of the tape type disposable diaper of the 1st example. It is an expansion state outline top view of a tape type disposable diaper of the 2nd example. It is an expansion state outline top view of a tape type disposable diaper of the 3rd example. It is an expansion state outline top view of a tape type disposable diaper of the 4th example. It is an expansion state outline top view of a tape type disposable diaper of the 5th example. It is an expansion state outline top view of a tape type disposable diaper of the 6th example. It is a top view of the example of a tape type disposable diaper. FIG. It is a 21-21 line arrow directional view. It is a 22-22 line arrow directional view. It is a top view which shows the various arrangement | sequence examples of a junction part.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The absorbent article of the present invention means a product that absorbs and retains body fluids such as disposable diapers, sanitary napkins, and absorbent pads.
The absorbent article has at least a stretchable region that can be stretched in the front-rear direction. In addition to the front-rear direction, it is also possible to extend and contract in a direction perpendicular to this (in the disposable diaper, the waist direction (product width direction)).

As shown in FIGS. 5 to 8, the stretchable region is between a first sheet layer 21 made of, for example, a non-woven fabric that does not have stretchability, and a second sheet layer 22 made of, for example, a non-woven fabric that does not have stretchability, The elastic film 30 that can be expanded and contracted in the front-rear direction is laminated, and the first sheet layer 21 and the second sheet layer 22 are directly or via the elastic film 30 with a large number of bonding portions. 40 is joined.
Here, “the first sheet layer 21 and the second sheet layer 22 are not stretchable” does not mean that the first sheet layer 21 and the second sheet layer 22 are not stretched at all. It means not.

At the time of joining, for example, as shown in FIG. 9, the first sheet layer 21, the elastic film 30, and the second sheet are disposed between the anvil roll 60 having the protrusions 60 a formed in a predetermined pattern on the outer surface and the ultrasonic horn 61. The sheet layer 22 is supplied, and ultrasonic melting energy is applied by the ultrasonic horn 61. For example, the elastic film 30 is mainly melted to join the first sheet layer 21 and the second sheet layer 22.
In addition, about the example of a joining form, it explains in full detail later.

  The elongation rate in the manufacturing process of the elastic film 30 (based on the length of the natural state being 100%) is, for example, that the peripheral speed of the driving anvil roll 60 is faster than the peripheral speed of the rear driving roll 62. It can be set by selecting the speed difference between the rolls. 63 is a guide roller.

  FIG. 6 schematically shows a cross section of the stretchable sheet after joining in the stretched state. When the stretched state of the stretchable sheet is released, as shown in FIG. 7 (schematic diagram), the stretchable sheet contracts due to the contraction force of the elastic film 30 and can be stretched by applying an external force in the front-rear direction (left-right direction in FIG. 7). Therefore, when the expansion / contraction direction of this stretchable sheet is matched with, for example, the front / rear direction of the disposable diaper, the disposable diaper can be expanded / contracted in the front / rear direction.

And since an elastic sheet can be manufactured with a predetermined area, when it is desired to apply a contracting force to the entire desired area, the elastic sheet cut into the desired area may be applied. In conventional disposable diapers, it is generally performed by fixing a plurality of thread rubbers in parallel to the sheet, but this reduces quality due to deterioration of thread rubber and hot melt adhesive for fixing to the sheet, In addition, it is inferior in terms of stable productivity during production. These problems can be solved by the above stretchable sheet.
Moreover, as can be seen from the contracted state of FIG. 7, the outer surface of the stretchable sheet is formed with regular fine wrinkles or folds, so that the wearer's skin feel is good.

On the other hand, in the above example, the first sheet layer 21 and the second sheet layer 22 are joined by melting the elastic film 30. In this case, (1) the mode in which the first sheet layer 21 or the second sheet layer 22 is joined on the surface of the elastic film 30, (2) the surface portion of the elastic film 30 is melted, and the first sheet layer 21 and the second sheet A mode of invading and bonding between the respective fibers of the layer 22 (3) Almost all of the elastic film 30 is melted and invaded and bonded between the respective fibers of the first sheet layer 21 and the second sheet layer 22. There are aspects. In the present invention, the bonding mode between the layers is not limited to these examples.
Among these aspects, in the aspect such as (3), it can be evaluated that the first sheet layer 21 and the second sheet layer 22 are joined directly, that is, without interposing an elastic film.
The above aspects (1) to (3) are cases where the melting point of the elastic film 30 is lower than the melting points of the first sheet layer 21 and the second sheet layer 22, but the melting point of the elastic film 30 is the first sheet layer. 21 and / or higher than the melting point of the second sheet layer 22. In this case, the elastic film 30 side surface portion of the first sheet layer 21 and / or the second sheet layer 22 is activated or melted and joined to the elastic film 30.
Furthermore, the elastic film 30 may be partly melted, and the first sheet layer 21 and / or the second sheet layer 22 may be joined by melting.
The 1st sheet layer 21 and / or the 2nd sheet layer 22 are nonwoven fabrics, and the fiber may have a core-sheath structure. In this case, for example, only the sheath component of the fiber can be melted and contribute to the joining.

The main feature of the present invention is that the width direction intermediate region has a stretchable region, and the width direction is different between the middle region and both side regions, so that the stretch stress between the width direction is different. It is.
As a means for this, the ratio of the total area of the joints included in the unit area of the region to the unit area, that is, the joint area ratio is selected.
The present invention provides a high effect or advantage when applied to a disposable diaper, particularly a tape-type disposable diaper. Let's assume that this is applied to a tape-type disposable diaper. For example, when the side edge region of the diaper also exhibits elasticity, the shape and flatness of the side edge region are not determined, and it is difficult to wear the diaper to the wearer. In addition, if the folds or wrinkles in the intermediate area that repeats unevenness in the front-rear direction reach the side edge area, so-called side leakage may occur. Therefore, it is desirable that the bonding area ratio of the side edge region is higher than that of the intermediate region, and is difficult to deform if necessary.

As shown in FIG. 1, the joint area ratio is a percentage of the total area of the joints 40, 40... Included in the unit area S. The unit area S in this case is desirably set to a size that includes 10 or more joints (it is difficult to compare the stretching stress with a small number). In the example of FIG. 1, 13 joint portions are included. Moreover, the external shape which defines unit area S may be other shapes, such as a rectangle and a circle, besides a square.
An example of the joint 40 is a circle shown in FIG. Of course, the shape may be an ellipse or a rectangle. In FIG. 1, Lm is an arrangement interval length in the machine direction, Lc is an arrangement interval length in an orthogonal direction (cross direction) orthogonal to the machine direction, Pm is a machine direction (MD pitch length, Pc is an orthogonal direction (cross direction: CD) ) Pitch length.

The aspect from which a junction area ratio changes with the area | regions in an elastic sheet was shown in FIGS.
In FIG. 2, for the regions A and B, the expansion stress is in the relationship of A> B by setting the joint area ratio to A <B.
For example, when the pitch length Pm and the pitch length Pc are long and A is compared with the case B when the pitch length Pm and the pitch length Pc are short, the case A (when the joint area ratio is low) is long. In the case where the pitch length Pm · Pc is short, the elongation ratio is larger than that in B (when the joint area ratio is high). As a result, the stretching stress has a relationship of A> B.
The form of FIG. 2 differs in the extensional stress in the lateral direction of FIG. 2 for each region, so that the region A having a large stretching stress is made to correspond to the intermediate region in the width direction of the absorbent article. And B area | region where expansion / contraction stress is small (so-called expansion / contraction is small) is made to respond | correspond to the both outer sides of center A area | region.

  In the case of FIG. 3, in the intermediate region, the B region having a small expansion and contraction stress is arranged before and after the intermediate region A in the front-rear direction. In this example, the front and rear B regions and the B region can correspond to, for example, the front and rear end portions of the disposable diaper, and since the stretching stress is small at the front and rear end portions, the shape stability is good, so the wearer It becomes easy to attach to.

In the present invention, the difference in the joint area ratio can be achieved by changing the joint area in addition to the density of the arrangement pattern.
In order to understand this, FIG. 4 shows an example in which a large number of small junctions are arranged in the region C so as to have the same junction area as the region D. By setting the joint area to A <C = D, the stretching stress is in the relationship of A> C = D.

By the way, the elastic film in the present invention may be stretchable only in the front-rear direction, but the use of the two-way stretchable film that stretches in the direction orthogonal to the waist is used around the waist or the waist especially in the case of a disposable diaper. Since expansion and contraction is imparted, there are advantages such as enhancing fit.
In this case, as described above, if the bonding area ratio of the side edge region is set higher than that of the intermediate region, the shape retaining property of the diaper is not substantially impaired even if the intermediate region expands and contracts in the width direction.

Physical properties such as the thickness, material, strain / stress characteristics, and melting point of the elastic film can be selected as appropriate. By selecting the relationship between this elastic film, the ultrasonic melting energy applied thereto, and the elongation rate of the elastic film at the time of manufacturing the stretchable sheet, as shown in FIG.
Through-holes 31 can be formed around the periphery. When the first sheet layer 21 and the second sheet layer 22 are formed of, for example, a nonwoven fabric, the nonwoven fabric exhibits air permeability. Therefore, for example, when used as an outer sheet or an outer sheet of a disposable diaper, the air permeability is good.

  The reason why the ventilation through hole 31 is formed is not necessarily clear, but the elastic film 30 is melted by the ultrasonic melting energy, and the coupling portion 40 is thinned by the pressing by the projection 60 a of the anvil roll 60. At this time, the elastic film 30 is also thinned, the peripheral portion of the joint portion 40 reaches the breaking strength, the breakage is started by the stretching stress acting on the stretched elastic film 3, shrinks to the balanced portion, and opens. it is conceivable that.

  FIG. 10 schematically shows an example of forming the through hole 31 in the case of a circular through hole. A substantially crescent-shaped through hole 31 is formed on both sides of the connecting portion 40 in the machine direction (extension direction).

  The coupling portion can have a long shape in a direction (cross direction: CD direction) orthogonal to the machine direction (extension direction). In this case, for example, as shown in FIG. 11, a semicircular through hole 31 having a large opening can be formed.

On the other hand, it is not essential for the through holes 31 to be formed in all the coupling portions. If it is required to reliably form the through-hole 31 or to open a large hole, the technique shown in FIG. 12 can be adopted.
That is, as shown in FIG. 12B, the stretchable sheet in which the coupling portion 40 is formed is passed between a pair of rolls 64 having ridges or protrusions 64a, and between adjacent protrusions 64a and 64a of one roll 64. The through-hole 31 can be formed by biting the protrusion 64a of the other roll 64 and applying a deformation force to the stretchable sheet.

(Application example for tape-type disposable diapers)
The elastic sheet formed as described above is applied to absorbent articles in general. First, an application example to a tape-type disposable diaper suitable as an application example will be described.

As shown in FIG. 13, the stretchable sheet formed as described above can be applied as an exterior sheet having a stretchable region 84 in the intermediate region in the width direction of the tape-type disposable diaper TD.
This has many advantages. That is, when the wearer gets up or bends, the front and back of the diaper may be lifted (separated) from the body surface or may be displaced in the front-rear direction. However, in the embodiment, there is no such problem and leakage can be prevented. Furthermore, by setting the expansion / contraction direction of the expansion / contraction region 84 to the front / rear direction, a heel along the width direction perpendicular to the front / rear direction is generated on the outer surface of the diaper due to the contraction of the expansion / contraction region 84, so that the wearer gets up from the supine state. Sometimes it also has an anti-slip effect on the buttocks.

  Further, as shown in FIG. 14, in the stretchable region 84 in the intermediate region in the width direction, the stretch rate differs between the intermediate portion 84B as the first stretchable region and the front and back portion 84A as the second stretchable region, The front and rear portions 84A are difficult to stretch (for example, the elongation rate is 200% or less), and the intermediate portion 84B can be easily stretched. In this case, since the front and rear regions do not extend excessively and there is resistance to elongation, the wearer has good wearability.

  As shown in FIG. 15, among the stretchable regions 84 in the width direction intermediate region, the stretch rate differs between the front and rear portions 84A and 84B, and the length in the width direction of the front and back portions 84A that are difficult to stretch is easily stretched. It can be larger than the width of 84B.

  As shown in FIG. 16, the expansion / contraction rate can be made different between the width direction outer side portion 84a and the center portion 84b in the expansion / contraction region 84 of the width direction intermediate region. In this case, when the area ratio of the joint portion is such that the central portion 84b> the outer portion 84a> both side portions, a cross-sectional bay shape along the wearer's surface is obtained, and the fitting property is high.

  As shown in FIG. 17, the disposable diaper TD may be of a so-called “fundoshi” type in which the front body is wrapped with a long tape Ta.

  Moreover, as shown in FIG. 18, what is called a "straight type" may be used. In the example shown in the figure, leg extension / contraction areas 83 and 83 are formed on both outer sides of the extension / contraction area 84. These leg-surrounding stretchable regions 83, 83 are formed on the inner side from both side edges, and do not impair the shape retention of the exterior sheet.

As a specific example of the absorbent article of the present invention, a cover-type disposable diaper that does not have an absorbent element on the use surface side is particularly suitable for a disposable diaper.
However, an extensible sheet can be used as an exterior sheet, and an absorbent element can be provided on the use surface side. As this absorber, an absorbent body mainly composed of cotton-like pulp or an absorbent body containing a polymer-absorbing polymer in a cotton-like pulp layer can be used. Is preferably less than 2 mm. In the case of an absorbent body of 2 mm or more, wrinkles and twists are generated in the absorbent body due to the shrinkage of the exterior sheet, which is liable to cause side leakage. The basis weight of the absorber is 200 g / m ² or less, more desirably 150 g / m ² or less.

  In a cover-type disposable diaper, when the absorbent body is not provided, or even if the absorbent body is provided, and the absorbent capacity is thin and the absorption capacity is small, it is desirable that through holes are not formed or few in the elastic film. For this purpose, the melting point of the elastic film 30 is set higher than the melting points of the first sheet layer 21 and / or the second sheet layer 22, but the joining portion is formed, but the through hole is not formed.

Absorbers to be used, including the absorbers that will be described in more detail later, are known ones such as pulp fiber stacks, aggregates of filaments such as cellulose acetate, or non-woven fabrics as basic elements. What mixed an adsorbent polymer, adhering, etc. can be used. This absorbent body can be packaged with a packaging sheet having liquid permeability and liquid retention, such as crepe paper, if necessary, for holding the shape and polymer.
The shape of the absorbent body can be formed in an almost hourglass shape having a narrowed portion narrower than the front and rear sides at the crotch portion, and can also have an appropriate shape such as a rectangular shape.

<Specific examples of tape-type disposable diapers>
FIGS. 19-22 has shown an example of the tape type disposable diaper, and this disposable diaper is an absorber between the inner surface of the above-mentioned lamination | stacking back surface sheet 1 and the liquid-permeable top sheet 2 which form a back surface. 3 is interposed.

(Liquid impervious laminated back sheet)
The liquid-impermeable laminated back sheet 1 extends outward from the periphery of the absorbent body 3 and blocks movement of excrement absorbed by the absorbent body 3 to the back surface side. As the elastic film of the laminated back sheet 1, a sheet having moisture permeability can be used without impairing water shielding from the viewpoint of preventing stuffiness.

  In order to make the appearance and feel like the outer surface of a cloth diaper, the entire back surface of the laminated back sheet 1 is covered with a nonwoven fabric layer (the first sheet layer 21 or the second sheet layer 22 described above), and both sheets 1 and 2 are covered. The outer peripheral edge of the diaper extends to the outer peripheral edge of the diaper. A spunbonded nonwoven fabric is suitable as the nonwoven fabric layer.

(Top sheet)
As the top sheet 2, a perforated or non-porous nonwoven fabric or a perforated plastic sheet is used. As the material fiber constituting the nonwoven fabric, synthetic fibers such as polyethylene or polypropylene, synthetic fibers such as polyester and amide, recycled fibers such as rayon and cupra, and natural fibers such as cotton can be used. Moreover, as a processing method of a nonwoven fabric, well-known methods, such as the spunlace method, the spun bond method, the SMS method, the thermal bond method, the melt blown method, the needle punch method, the air through method, the point bond method, can be used. The basis weight of the nonwoven fabric used for the liquid-permeable top sheet 2 is preferably 15 to 30 g / m ² , and the thickness is preferably 0.05 to 1 mm.

  The top sheet 2 extends outward from the periphery of the absorber 3, and a portion extending outward from the side edge of the absorber 3 is fixed to the laminated back sheet 1 with, for example, a hot melt adhesive. In addition, the dot pattern in a figure represents the adhering part.

(3D gathering around the legs)
If necessary, a three-dimensional gather around the legs can be provided, and an example of the form is shown. The leg gathering three-dimensional gather sheets 4 and 4 can use various non-woven fabrics (preferably spunbond non-woven fabrics), plastic films similar to those used for back sheets, or these stretchable sheets. From the viewpoint of the touch, a nonwoven fabric subjected to a water repellent treatment is preferable. The projecting portion on the center side in the width direction of the three-dimensional gather sheet around the legs is fixed to the inner surface of the article (in the illustrated form, the top sheet 2 surface) by means such as hot melt adhesive at the both ends in the front-rear direction, and is used as a lying portion. However, the intermediate part in the front-rear direction between them is a non-fixed free part, and the end part of this free part (end part on the center side in the width direction in the unfolded state) is elongated such as rubber thread. 4 G of elastic elastic expansion-contraction area | region materials are being fixed with the hot-melt-adhesive agent etc. in the state extended | stretched along the front-back direction. In the illustrated example, a plurality of the elongated elastic elastic members 4G are provided with a predetermined interval, but one may be used. As shown in FIG. 22, as a result of the contraction force of the elongated elastic expansion / contraction member 4G, this free portion is formed by a three-dimensional gathering around the legs that stands on the use surface of the diaper (the surface of the top sheet 2 in the illustrated embodiment). Configure.

(Fastening tape)
Fastening tapes T that protrude from the side edges are attached to the side flaps of the back part B, and a front target tape 6 is attached to the waist part surface of the abdomen part F along the width direction. When wearing on the body, with the diaper applied to the body, the fastening tape T on both sides is turned from each side of the waist to the abdomen outer surface and fastened to the front target tape 6 via the hook material 5. The front target tape 6 can be omitted. In this case, the fastening tape T is directly hooked and fixed to the nonwoven fabric on the outer surface of the diaper. Reference numeral 7 denotes a dividing perforation.

The constituent material of the first sheet layer 21 and the second sheet layer 22 can be used without particular limitation as long as it is a sheet, but it is preferable to use a nonwoven fabric from the viewpoint of air permeability and flexibility. The nonwoven fabric is not particularly limited as to what the raw fiber is. For example, synthetic fibers such as olefins such as polyethylene and polypropylene, polyesters and polyamides, recycled fibers such as rayon and cupra, natural fibers such as cotton, and mixed fibers and composite fibers using two or more of them. Etc. can be illustrated. Furthermore, the nonwoven fabric may be manufactured by any processing. Examples of the processing method include known methods such as a spunlace method, a spunbond method, a thermal bond method, a melt blown method, a needle punch method, an air through method, and a point bond method. When using a nonwoven fabric, the basis weight is preferably about 10 to 25 g / m ² .

By the way, the shape in the natural length state of each joint part 40 and the through-hole 31 is arbitrary, such as a perfect circle, an ellipse, polygons, such as a rectangle (including a linear or rounded thing), a star shape, a cloud shape, etc. It can be made into the shape. The size of each joint 40 may be determined as appropriate, but if it is too large, the effect of the hardness of the joint 40 on the feel will increase, and if it is too small, the joint area will be small and the materials will not be sufficiently bonded together. Therefore, in the normal case, the area of each joint 40 is preferably about 0.14 to 3.5 mm ² . The opening area of each through hole 31 may be equal to or larger than the joint portion because the joint portion is formed through the through hole 31, but is preferably about 1 to 1.5 times the area of the joint portion.

Moreover, as a junction part of this invention, although you may transfer directly from a main expansion-contraction area | region to a non-expansion area | region, the transition expansion / contraction area | region of the intermediate | middle can also be formed.
In general, the area and the area ratio of each joint 40 in each region are preferably set as follows.
(Non-stretchable area)
Area of the joint 40: 0.14 to 3.5 mm ² (particularly 0.25 to 1.0 mm ² )
Area ratio of the joint 40: 16 to 45% (especially 25 to 45%)
(Main stretchable region 84)
Area of the joint 40: 0.14 to 3.5 mm ² (particularly 0.14 to 1.0 mm ² )
Area ratio of the joint 40: 1.8 to 19.1% (particularly 1.8 to 10.6%)
(Transition stretch region)
Area of the joint 40: 0.14 to 3.5 mm ² (particularly 0.25 to 1.0 mm ² )
Area ratio of the joint 40: 8 to 22.5% (particularly 12.5 to 22.5%)

  The plane arrangement of the joints 40 and the through-holes 31 can be determined as appropriate, but a plane arrangement that is regularly repeated is preferable, such as an oblique lattice shape as shown in FIG. 23 (a), or as shown in FIG. 23 (b). Hexagonal lattice shape (these are also called staggered shapes), square lattice shape as shown in FIG. 23 (c), rectangular lattice shape as shown in FIG. 23 (d), and parallel shape as shown in FIG. 23 (e). Body lattice (in the form shown in the figure, two groups are provided so that a large number of groups of parallel diagonal rows intersect each other), etc. (in which these are inclined at an angle of less than 90 degrees with respect to the expansion / contraction direction) In addition to those that are regularly repeated, the group of joints 40 (group unit arrangement may be regular or irregular, and may be a pattern, a character shape, etc.) shall be regularly repeated. You can also. The arrangement form of the joint 40 and the through holes 31 may be the same in the main stretchable region 84, the transition stretchable region, and the non-stretchable region, or may be different.

The elastic film 30 is not particularly limited, and can be used without particular limitation as long as it is a resin film having its own elasticity. For example, a styrene-based elastomer, an olefin-based elastomer, a polyester-based elastomer, a polyamide-based elastomer, and a polyurethane-based film can be used. A product obtained by processing one or two or more blends of thermoplastic elastomers such as elastomers into a film by extrusion molding such as a T-die method or an inflation method can be used. Moreover, as the elastic film 30, the thing in which many holes and slits were formed for ventilation other than a non-porous thing can also be used. In particular, the tensile strength in the stretching direction is 8 to 25 N / 35 mm, the tensile strength in the direction perpendicular to the stretching direction is 5 to 20 N / 35 mm, the tensile elongation in the stretching direction is 450 to 1050%, and the direction perpendicular to the stretching direction. It is preferable that the elastic film 30 has a tensile elongation of 450 to 1400%. Note that the tensile strength and tensile elongation (breaking elongation) were JIS K7127 except that a tensile tester (for example, AOUTGRAPHAGS-G100N manufactured by SHIMADZU) was used and the test piece was a rectangular shape having a width of 35 mm and a length of 80 mm. According to 1999 “Plastics—Testing Method for Tensile Properties”, it means a value measured with an initial chuck interval of 50 mm and a tensile speed of 300 mm / min. Although the thickness of the elastic film 30 is not specifically limited, It is preferable that it is about 20-40 micrometers. The basis weight of the elastic film 30 is not particularly limited, but is preferably about 30 to 45 g / m ² , particularly preferably about 30 to 35 g / m ² .

<Explanation of terms in the specification>
The following terms in the specification have the following meanings unless otherwise specified in the specification.
“Elongation rate” means a value when the natural length is 100%.
・ "Weight" is measured as follows. After the sample or test piece has been pre-dried, it is left in a test room or apparatus in a standard state (test location is temperature 20 ± 5 ° C., relative humidity 65% or less) to obtain a constant weight. Pre-drying refers to making a sample or test piece constant in an environment where the relative humidity is 10 to 25% and the temperature does not exceed 50 ° C. In addition, it is not necessary to perform preliminary drying about the fiber whose official moisture content is 0.0%. A sample with a size of 200 mm × 250 mm (± 2 mm) is cut out from the test piece in a constant weight using a rice-basis plate (200 mm × 250 mm, ± 2 mm). Measure the weight of the sample, multiply it by 20, calculate the weight per square meter, and use it as the basis weight.
- "thickness" is used automatic thickness measuring instrument (KES-G5 Handy Compression measurement program), load: 10 gf / cm ^2, and the pressure area: automatically measured under the conditions of 2 cm ^2.
・ If there is no description about the environmental conditions in the test and measurement, the test and measurement shall be performed in a test room or equipment in the standard condition (test location is temperature 20 ± 5 ℃, relative humidity 65% or less). .

  INDUSTRIAL APPLICABILITY The present invention can be used for absorbent articles in general having a stretchable structure such as a pants-type disposable diaper as described above, various disposable diapers such as a tape type and a pad type, and a sanitary napkin.

  A ... D region, Ba ... back body, Fr ... front body, T, Ta ... tape, TD ... tape-type disposable diaper, 1 ... elastic sheet, 2 ... top sheet, 21 ... first sheet layer, 22 ... second Sheet layer, 30 ... elastic film, 31 ... through hole, 40 ... joint, 84 ... stretchable region.

Claims (9)

An absorbent article that is a disposable diaper provided with an elastic sheet extending in the front-rear direction around the inseam area in the width direction intermediate region and having an elastic region extending and contracting in the front-rear direction ,
In the stretchable sheet, an elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that does not have stretchability and the second sheet layer, and the first sheet layer and the first sheet layer 2 sheet layers are joined at a large number of spaced joints, either directly or via an elastic film,
The stretchable sheet contracts due to the contraction force of the elastic film, and is extensible when an external force is applied in the front-rear direction.
In the stretchable sheet, the joint area ratio occupied by the total area of the joints included in the unit area is different between the intermediate region and the both side regions in the width direction, so that the stretching in the front-rear direction is performed between the width directions. An absorbent article characterized by different stresses. An absorbent article that is a sanitary napkin provided with an elastic sheet having an elastic region extending in the front-rear direction and extending in the front-rear direction in the intermediate region in the width direction ,
In the stretchable sheet, an elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that does not have stretchability and the second sheet layer, and the first sheet layer and the first sheet layer 2 sheet layers are joined at a large number of spaced joints, either directly or via an elastic film,
The stretchable sheet contracts due to the contraction force of the elastic film, and is extensible when an external force is applied in the front-rear direction.
In the stretchable sheet, the joint area ratio occupied by the total area of the joints included in the unit area is different between the intermediate region and the both side regions in the width direction, so that the stretching in the front-rear direction is performed between the width directions. An absorbent article characterized by different stresses.   The absorbent article according to claim 1 or 2, wherein the joints are arranged in a staggered pattern. An absorbent article comprising a stretchable sheet that is stretchable in the front-rear direction and has a stretchable region in the intermediate region in the width direction,
In the stretchable sheet, an elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that does not have stretchability and the second sheet layer, and the first sheet layer and the first sheet layer 2 sheet layers are joined at a large number of spaced joints, either directly or via an elastic film,
The stretchable sheet contracts due to the contraction force of the elastic film, and is extensible when an external force is applied in the front-rear direction.
In the stretchable sheet, the joint area ratio occupied by the total area of the joints included in the unit area is different between the intermediate region and the both side regions in the width direction, and is also different in the intermediate region. An absorbent article characterized in that the stretching stress in the front-rear direction is different between the width directions. An absorbent article comprising a stretchable sheet that is stretchable in the front-rear direction, having a first stretchable region in the front-rear direction intermediate region of the widthwise intermediate region, and a second stretchable region in front of and behind the front-rear direction intermediate region. And
In the stretchable sheet, an elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that does not have stretchability and the second sheet layer, and the first sheet layer and the first sheet layer 2 sheet layers are joined at a large number of spaced joints, either directly or via an elastic film,
The stretchable sheet contracts due to the contraction force of the elastic film, and is extensible when an external force is applied in the front-rear direction.
In the stretchable sheet, the joint area ratio occupied by the total area of the joints included in a unit area is different in the width direction in the front-rear direction intermediate region and the both side regions in the width direction. An absorptive article characterized in that the stretching stress in the front-rear direction is different from each other, and the stretching stress in the front-rear direction is different due to the difference between the front-rear direction intermediate region and the front-rear region. An absorbent article that is a tape-type disposable diaper that can be stretched in the front-rear direction and has an stretchable sheet having an stretchable region in the intermediate region in the width direction as an exterior sheet ,
In the exterior sheet , an elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that does not have stretchability and the second sheet layer, and the first sheet layer and the first sheet layer 2 sheet layers are joined at a large number of spaced joints, either directly or via an elastic film,
The exterior sheet is contracted by the contraction force of the elastic film, and is extensible when an external force is applied in the front-rear direction.
In the exterior sheet , the joint area ratio occupied by the total area of the joints included in a unit area is different between the intermediate region and the two side regions in the width direction, so that stretching in the front-rear direction is performed between the width directions. An absorbent article characterized by different stresses. It is an absorbent article that is a tape-type disposable diaper that can be stretched in the front-rear direction and the width direction, and has a stretchable sheet having a stretchable region in the widthwise intermediate region as an exterior sheet ,
In the exterior sheet , an elastic film that can be stretched at least in the front-rear direction is laminated between the first sheet layer that does not have stretchability and the second sheet layer, and the first sheet layer and the first sheet layer 2 sheet layers are joined at a large number of spaced joints, either directly or via an elastic film,
The exterior sheet is contracted by the contraction force of the elastic film, and is extensible when an external force is applied in the front-rear direction.
In the exterior sheet , the joint area ratio occupied by the total area of the joints included in a unit area is different between the intermediate region and the two side regions in the width direction, so that stretching in the front-rear direction is performed between the width directions. An absorbent article characterized by different stresses. An absorbent article that is a tape-type disposable diaper that can be stretched at least in the front-rear direction and has an stretchable sheet having an stretchable region at least in the widthwise intermediate region as an exterior sheet ,
In the exterior sheet , an elastic film that can be stretched at least in the front-rear direction is laminated between a first sheet layer that does not have stretchability and a second sheet layer that does not have stretchability. The sheet layer and the second sheet layer are formed by being joined through through holes formed in the elastic film, with a large number of spaced joints.
The stretchable region is contracted by the contraction force of the elastic film, and can be expanded by applying an external force in the front-rear direction.
In the exterior sheet , the joint area ratio occupied by the total area of the joints included in a unit area is different between the intermediate region and the two side regions in the width direction, so that stretching in the front-rear direction is performed between the width directions. An absorbent article characterized by different stresses. It is an absorbent article that is a tape-type disposable diaper that can be stretched in the front-rear direction and the width direction, and has a stretchable sheet having a stretchable region in the widthwise intermediate region as an exterior sheet ,
The exterior sheet is formed by laminating an elastic film stretchable in the front-rear direction and the width direction between a first sheet layer having no stretchability and a second sheet layer having no stretchability, and The first sheet layer and the second sheet layer are formed by being joined through through holes formed in the elastic film, with a large number of spaced joints.
The stretchable region is contracted by the contraction force of the elastic film, and can be expanded by applying an external force in the front-rear direction.
In the exterior sheet , the joint area ratio occupied by the total area of the joints included in a unit area is different between the intermediate region and the two side regions in the width direction, so that stretching in the front-rear direction is performed between the width directions. An absorbent article characterized by different stresses.

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