JP7315350B2 - Manufacturing method of pants-type disposable diaper - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a pants-type disposable diaper.

Pants-type disposable diapers generally have an outer body extending from the front body to the back body, or an outer body provided separately from the front body and the back body, and an inner body including an absorbent attached to the outer body from the front body to the back body. Side seals are formed by joining both sides of the outer body of the front body and both sides of the outer body of the back body to form a waist opening and a pair of left and right leg openings.

In such underpants-type disposable diapers, it is common to provide an extensible structure in the exterior body in order to improve fit to the body. For example, a waist region defined as a range in the front-rear direction corresponding to the side seal portions and an intermediate region located between the front and rear waist regions have a stretchable structure, which provides a relatively high fit to the body (see Patent Documents 1 to 5, for example).

A representative stretchable structure of a pants-type disposable diaper is provided with elongated elastic members spaced apart from each other along the stretching direction between the overlapping inner and outer sheet layers. The inner sheet layer and the outer sheet layer form a planar stretchable region and play the role of covering and hiding the elastic member, and the elastic member built in between the inner sheet layer and the outer sheet layer plays the role of generating force for elastic stretching. The elastic member is fixed to the inner sheet layer and the outer sheet layer at least at portions located at both ends of the elastic region while being stretched in the elastic direction. By this fixation, the elastic member and the inner sheet layer and the outer sheet layer are integrated, and the inner sheet layer and the outer sheet layer are contracted by the contractile force of the elastic member to form folds (including wrinkled ones. They are formed not only in the natural state but also in the state in which the elastic member is stretched. Hereinafter, simply referred to as folds.), and when the contracted state is stretched against the contractile force of the elastic member, the folds are unfolded. Normally, the inner sheet layer and the outer sheet layer are unfolded with no folds at the limit of elastic elongation, and the folds are formed as the elastic member shrinks, and the folds are most closely formed in the natural length state.

In such a stretchable structure, if the inner sheet layer and the outer sheet layer are free from each other, one of the nonwoven fabric layers may partially or wholly float from the other nonwoven fabric layer, causing unnecessary folds or bulges. In addition, in order to generate stretchability by the elastic member, the elastic member must extend over the entire stretchable region in the stretchable direction, and at least portions located at both ends of the stretchable region in the stretchable direction must be fixed to the inner sheet layer and the outer sheet layer, and the inner sheet layer and the outer sheet layer must be contracted as the elastic member shrinks in its natural length state. That is, it is necessary to join the inner sheet layer and the outer sheet layer and to fix the elastic member to the inner sheet layer and the outer sheet layer.

Currently, hot-melt adhesives are most often the means of choice for securing elastic members to inner and outer sheet layers. On the other hand, the bonding between the inner sheet layer and the outer sheet layer is often performed by welding such as ultrasonic welding in order to reduce the amount of hot melt adhesive used. In particular, the most representative structure is known as a combined structure in which the inner sheet layer and the outer sheet layer are joined via a hot-melt adhesive at the position of the elastic member, thereby both joining the inner sheet layer and the outer sheet layer and fixing the elastic member to the inner sheet layer and the outer sheet layer.

On the other hand, the waist region and the intermediate region overlap with the front-rear region having the absorber, and there is an inner-outer joint for joining the inner body and the outer body in the region. Therefore, even if an elastic member is provided so as to traverse the front-rear direction range having this absorber, its stretching function is limited by the rigidity of the absorber. In addition, the absorbent body may shrink in the width direction, which may deteriorate the feeling of wearing and the appearance of the absorbent body, or the absorbent body may be twisted or cracked, resulting in a decrease in absorption performance.

For this reason, conventionally, an elastic member is continuously attached to the outer body along the width direction, and the stretchability generated by the elastic member is canceled in the portion overlapping the absorbent body, thereby forming a non-stretchable region in the outer body (for example, see Patent Documents 1 to 5). When fixing the elastic member and joining the inner sheet layer and the outer sheet layer with the hot-melt adhesive as in the dual-use structure described above, there are roughly two methods for reducing elasticity.

That is, the first method is a method of finely cutting the portion of the elastic member located in the non-stretchable region. The second method is to form an independently shrinkable portion that is not fixed to the inner sheet layer and the outer sheet layer or that is weakly fixed to the inner sheet layer and the outer sheet layer or is weakly fixed with a hot-melt adhesive in a portion located in the non-stretchable region of the elastic member, cuts the independently shrinkable portion at one point in the middle of the width direction, and shrinks the independently shrinkable portion to a natural length or a state close to it without involving the inner sheet layer and the outer sheet layer. The second method has the advantage of having only one cutting point compared to the first method.

However, in the second method, the independently shrinkable portions of the elastic members are either unfixed or weakly fixed to the inner sheet layer and the outer sheet layer by a hot-melt adhesive, so that there is no or weak bonding between the inner sheet layer and the outer sheet layer in the non-stretchable region. As a result, the outer sheet layer may be lifted from the inner sheet layer, or the outer sheet layer may have irregular and large wrinkles, thereby deteriorating the appearance.

On the other hand, in fixing the elastic members to the inner sheet layer and the outer sheet layer with a hot-melt adhesive, it is sufficient to fix the independently shrinkable portions to some extent firmly. In this case, a good non-stretchable region is not formed, and there is a risk of spoiling the appearance.

Japanese Patent Publication No. 2015-512296 Japanese Patent No. 5779738 JP 2015-58061 A JP 2016-067912 A JP 2016-000116 A

Therefore, the main object of the present invention is to prevent deterioration of the appearance of a non-stretchable region formed by cutting the elastic member at one point in a stretchable structure in which an inner sheet layer and an outer sheet layer are joined via a hot-melt adhesive at the position of the elastic member.

The pants-type disposable diaper that solves the above problems is as follows.
<First Aspect>
An integrated exterior covering from the front body to the back body, or an exterior body provided separately for the front body and the back body;
an inner body including an absorbent attached to the outer body so as to extend from the front body to the back body;
a side seal portion in which both side portions of the exterior body of the front body and both side portions of the exterior body of the back body are respectively joined;
Equipped with a waist opening and a pair of left and right leg openings,
The exterior body has a non-stretchable region provided in the middle in the width direction and stretchable regions provided on both sides in the width direction of the non-stretchable region in the front-back direction range including the absorbent body,
The elastic region has an inner sheet layer, an outer sheet layer, and a plurality of elongated elastic members along the width direction attached between the inner sheet layer and the outer sheet layer at intervals in the front-rear direction.
In the elastic region, the inner sheet layer and the outer sheet layer are joined by a hot melt adhesive placed at least at the position of the elastic member, and the elastic member is fixed to the inner sheet layer and the outer sheet layer,
The non-stretchable region has an inner sheet layer and an outer sheet layer that are continuous from the stretchable region, and an independently shrinkable portion that remains between the inner sheet layer and the outer sheet layer and that is continuous from the elastic member of the stretchable region.
In the non-stretchable region, either the inner sheet layer and the outer sheet layer are not bonded and the independently contractible portion is not fixed to the inner sheet layer and the outer sheet layer, or the inner sheet layer and the outer sheet layer are bonded weaker than the stretchable region, and the independently shrinkable portion is fixed to the inner sheet layer and the outer sheet layer weaker than the elastic member of the stretchable region, only by a hot melt adhesive placed at the position of the independently shrinkable portion.
In pants-type disposable diapers;
The non-stretchable region has a reinforcing joint where the inner sheet layer and the outer sheet layer are directly welded at least in one location including the central portion in both the width direction and the front-rear direction.
A pants-type disposable diaper characterized by:

(Effect)
In the non-stretchable region of the pants-type disposable diaper, the inner sheet layer and the outer sheet layer are directly welded together at at least one location including the central portion in both the width direction and the front-rear direction. Therefore, the bonding between the inner sheet layer and the outer sheet layer in the non-stretchable region is reinforced, and the situation that the outer sheet layer is lifted from the inner sheet layer and the irregular and large wrinkles of the outer sheet layer hardly occur, and the appearance is less likely to deteriorate.

<Second Aspect>
The reinforcing joints are provided in a dotted line or a line along the width direction between the independently contracted portions adjacent in the front-rear direction,
A pants-type disposable diaper according to the first aspect.

(Effect)
When the reinforcing joint has such a shape and arrangement, even if the independent contraction portion of the elastic member moves in the front-rear direction, the movement is restricted by the reinforcement joint, so that it does not intersect with other independently contracting portions adjacent in the front-rear direction. Therefore, it is possible to prevent the deterioration of the appearance due to the irregular shape of the independent contraction portion of the elastic member.

<Third Aspect>
The reinforcing joint portion is provided only in the center portion in the width direction of the non-stretchable region, and the lengths of the independently contractible portions on both sides in the width direction are equal.
A pants-type disposable diaper according to the first or second aspect.

(Effect)
This structure allows the cutting of the elastic member and the formation of the reinforcing joint portion to be formed by simultaneous pressurization and heat processing, and the appearance including the reinforcing joint portion is left-right symmetrical about the center in the width direction, which is preferable in that it is excellent in appearance.

<Fourth Aspect>
The reinforcing joint is provided in a display form consisting of a pattern, a picture, a letter, or a combination thereof,
A pants-type disposable diaper according to the first aspect.

(Effect)
By forming the reinforcing joint portion in the indicated shape in this manner, the design of the non-stretchable region can be improved.

<Fifth Aspect>
A method for manufacturing a pants-type disposable diaper according to the first aspect, comprising:
When forming the exterior body, the elastic member is arranged in a stretched state between the inner sheet layer and the outer sheet layer so as to pass through the portion to be the stretchable region and the portion to be the non-stretchable region,
In the stretchable region, at least the inner sheet layer and the outer sheet layer are joined with a hot-melt adhesive applied to the peripheral surface of the elastic member, and the elastic member is fixed to the inner sheet layer and the outer sheet layer,
In the portion to be the non-stretchable region, either the inner sheet layer and the outer sheet layer are not joined and the independently contractible portion is fixed to the inner sheet layer and the outer sheet layer, or the inner sheet layer and the outer sheet layer are joined weaker than the portion to be the stretchable region only by a hot melt adhesive applied to the peripheral surface of the elastic member, and the elastic member is fixed to the inner sheet layer and the outer sheet layer weaker than the portion to be the stretchable region;
After that, at one point in the width direction of the portion to be the non-stretchable region, the elastic member is cut by sandwiching from the inner side of the inner sheet layer and the outer side of the outer sheet layer and applying pressure and heat,
Before or after the elastic member is cut, or at the same time as the elastic member is cut, the inner sheet layer and the outer sheet layer are sandwiched from the inner side of the inner sheet layer and the outer side of the outer sheet layer, and the inner sheet layer and the outer sheet layer are sandwiched from the inner side and the outer side of the outer sheet layer, and the portions to be the non-stretchable regions are pressed and heated to form the reinforcing joint.
A method for manufacturing a pants-type disposable diaper, characterized by:

(Effect)
By this manufacturing method, the underpants-type disposable diaper of the first aspect can be manufactured.

<Sixth Aspect>
After cutting the elastic member, the reinforcing joint is formed in a width direction range that does not have the independent contraction portion.
A method for manufacturing a pants-type disposable diaper according to the fifth aspect.

(Effect)
After the elastic member is cut, it is preferable to form the reinforcing joint portion in the width direction range that does not have the independently shrinkable portion, because there is no risk of pressurizing and heating the elastic member when forming the reinforcing joint portion.

<Seventh Aspect>
The cutting of the elastic member and the formation of the reinforcing joint are performed simultaneously only at the center portion in the width direction of the non-stretchable region.
A method for manufacturing a pants-type disposable diaper according to the fifth aspect.

(Effect)
A pants-type disposable diaper of the third aspect, which is excellent in appearance, can be manufactured.

<Eighth Aspect>
Before cutting the elastic member, the reinforcing joint is formed in a dotted line or a line along the width direction between the independently contractible portions adjacent in the front-rear direction.
A method for manufacturing a pants-type disposable diaper according to the fifth aspect.

(Effect)
By forming the reinforcing joints in such an arrangement prior to cutting the elastic member, when the independently contracting portion contracts after cutting, the independently contracting portion is less likely to have an irregular shape.

As described above, according to the present invention, in a stretchable structure in which an inner sheet layer and an outer sheet layer are joined via a hot-melt adhesive at the position of an elastic member, it is possible to prevent deterioration in appearance of a non-stretchable region formed by cutting the elastic member at one point.

Fig. 2 is a plan view showing the inner surface of the underpants-type disposable diaper when the diaper is unfolded; Fig. 2 is a plan view showing the outer surface of the underpants-type disposable diaper when the diaper is unfolded; 3 is a cross-sectional view taken along line 3-3 of FIG. 1; FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. 1; FIG. (a) 5-5 cross-sectional view of FIG. 1, and (b) 6-6 cross-sectional view of FIG. 1 is a perspective view of a pants-type disposable diaper; FIG. FIG. 2 is a cross-sectional view corresponding to the 5-5 cross section of FIG. 1; Fig. 2 is a plan view showing the outer surface of the underpants-type disposable diaper when the diaper is unfolded; FIG. 3 shows (a) a plan view after cutting the elastic member, (b) a cross-sectional view after cutting the elastic member, and (c) a cross-sectional view before cutting the elastic member, showing the non-stretchable region and its neighboring region. FIG. 3 shows (a) a plan view after cutting the elastic member, (b) a cross-sectional view after cutting the elastic member, and (c) a cross-sectional view before cutting the elastic member, showing the non-stretchable region and its neighboring region. FIG. 3 shows (a) a plan view after cutting the elastic member, (b) a cross-sectional view after cutting the elastic member, and (c) a cross-sectional view before cutting the elastic member, showing the non-stretchable region and its neighboring region. FIG. 3 shows (a) a plan view after cutting the elastic member, (b) a cross-sectional view after cutting the elastic member, and (c) a cross-sectional view before cutting the elastic member, showing the non-stretchable region and its neighboring region. It is a perspective view which shows the cutting|disconnection of an elastic member, and the formation process of a reinforcement joint part. It is a front view which shows roughly the cutting|disconnection of various elastic members, and the formation process of a reinforcement joint part. It is (a) a top view and (b) sectional drawing which show a post-processing tape part. FIG. 4 is a cross-sectional view showing a state after peeling of the post-treatment tape; FIG. 4 is a perspective view showing a state in which the diaper is rolled up and fixed;

An example of a pants-type disposable diaper will be described in detail below with reference to the accompanying drawings. A dot pattern portion in the cross-sectional view indicates a hot-melt adhesive as a bonding means for bonding each component located on the front side and the back side. The hot melt adhesive can be applied by known methods such as slot coating, continuous line or dotted line bead coating, spiral, Z-shaped spray coating, or pattern coating (transfer of hot melt adhesive by letterpress method). Alternatively or additionally, at the fixing portion of the elastic member, a hot melt adhesive can be applied to the outer peripheral surface of the elastic member to fix the elastic member to the adjacent member. Hot-melt adhesives include, for example, EVA-based, adhesive rubber-based (elastomer-based), olefin-based, and polyester-polyamide-based adhesives, and can be used without particular limitation. As a joining means for joining each constituent member, a means by material welding such as heat sealing or ultrasonic sealing can be used.

In addition, as the nonwoven fabric in the following description, a known nonwoven fabric can be appropriately used depending on the site and purpose. As the constituent fibers of the nonwoven fabric, for example, in addition to synthetic fibers such as olefin-based, polyester-based, and polyamide-based fibers such as polyethylene or polypropylene (including composite fibers such as core-sheath fibers in addition to single-component fibers), regenerated fibers such as rayon and cupra, natural fibers such as cotton, etc., can be selected without particular limitation, and these can be mixed and used. In order to increase the softness of the nonwoven fabric, it is preferable to use crimped fibers as the constituent fibers. The constituent fibers of the nonwoven fabric may be hydrophilic fibers (including those made hydrophilic by a hydrophilic agent), hydrophobic fibers or water-repellent fibers (including water-repellent fibers made water-repellent by a water-repellent agent). Nonwoven fabrics are generally classified into short fiber nonwoven fabrics, long fiber nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics, thermal bond (air-through) nonwoven fabrics, needle punch nonwoven fabrics, point bond nonwoven fabrics, laminated nonwoven fabrics (SSS nonwoven fabrics in which the same or similar nonwoven fabric layers are laminated, SMS nonwoven fabrics in which different nonwoven fabric layers are laminated, in which a meltblown layer is sandwiched between spunbond layers, SMS nonwoven fabrics, SMMS nonwoven fabrics, etc.), etc. I can.

1 to 6 show a pants-type disposable diaper 100. FIG. The pants-type disposable diaper 100 includes a front outer body 12F that forms a front body F, a rear outer body 12B that forms a back body B, and an inner body 200 that extends from the front outer body 12F to the rear outer body 12B through the crotch and is fixed to the front outer body 12F and to the rear outer body 12B. The side seal portion 12A is formed by joining the both sides of B, the opening formed by the front and rear end portions of the exterior bodies 12F and 12B is the waist opening WO through which the wearer's torso passes, and the portions surrounded by the lower edges of the exterior bodies 12F and 12B and the side edges of the interior body 200 on both sides in the width direction WD of the interior body 200 are leg openings LO through which the legs are passed. The inner body 200 is a portion that absorbs and retains excrement such as urine, and the outer body 12 is a portion that supports the inner body 200 against the wearer's body. Symbol Y indicates the total length of the diaper in the unfolded state (length in the front-rear direction from the edge of the waist opening WO of the front body F to the edge of the waist opening WO of the back body B), and symbol X indicates the total width of the diaper in the unfolded state.

In addition, the pants-type disposable diaper 100 has a waist region T defined as a front-back direction range having the side seal portions 12A (a front-back direction range from the waist opening WO to the upper ends of the leg openings LO), and an intermediate region L defined as a front-back direction range (between the front-back direction region having the side seal portions 12A of the front body F and the front-back direction region having the side seal portions 12A of the back body B) forming the leg openings LO. The waist region T can be divided into a “waist portion” W conceptually forming the edge of the waist opening and a “lower waist portion” U below this. Normally, when there is a boundary where the elastic stress in the width direction WD changes in the waist region T (for example, the thickness or elongation rate of the elastic member changes), the waist portion W is closer to the waist opening WO than the boundary closest to the waist opening WO. If there is no such boundary, the waist portion W is closer to the waist opening WO than the absorber 56 or the inner body 200. The lengths in the front-rear direction differ depending on the size of the product and can be determined as appropriate. For example, the waist portion W can be 15 to 40 mm, and the lower waist portion U can be 65 to 120 mm. On the other hand, both side edges of the intermediate region L are constricted in a U-shape or curvilinear shape along the circumference of the wearer's leg, and this is a portion into which the wearer's leg is inserted. As a result, the unfolded pants-type disposable diaper has a substantially hourglass shape as a whole.

(inner body)
The inner body 200 can be of any shape, but is rectangular in the illustrated example. As shown in FIGS. 3 to 5, the inner body 200 includes a body-side top sheet 30, a liquid-impermeable sheet 11, and an absorbent element 50 interposed therebetween. Reference numeral 40 denotes an intermediate sheet (second sheet) provided between the top sheet 30 and the absorbent element 50 in order to quickly transfer the liquid permeating through the top sheet 30 to the absorbent element 50. Reference numeral 60 denotes rise gathers 60 which are provided on both sides of the inner body 200 and stand on the body side in order to prevent leakage of excrement to both sides of the inner body 200.

Fixing of the inner body 200 to the outer bodies 12F and 12B can be performed by means of material welding such as heat sealing or ultrasonic sealing, or hot melt adhesive. In the illustrated example, the back surface of the inner body 200, that is, in this case, the back surface of the liquid-impermeable sheet 11 and the mounting portion 65 of the rising gathers 60 are fixed to the inner surface of the outer body 12 by a hot-melt adhesive applied. The inner/outer fixing portion 201 for fixing the inner body 200 and the outer bodies 12F and 12B can be provided in substantially the entire region where the two overlap, and is usually preferably provided in a portion excluding both ends in the width direction WD of the inner body 200.

(top sheet)
The top sheet 30 has the property of being permeable to liquid, and examples thereof include perforated or non-perforated nonwoven fabrics and porous plastic sheets.

When the rising gathers 60 are provided, both sides of the top sheet 30 are passed between the liquid-impermeable sheet 11 and the rising gathers 60, wrapped around to the back side of the absorbent element 50, and joined to the liquid-impermeable sheet 11 and the rising gathers 60.

The top sheet 30 is desirably fixed to a member adjacent to the back side by means of material welding such as heat sealing or ultrasonic sealing, or hot-melt adhesive for the purpose of preventing misalignment with respect to the member on the back side. In the illustrated example, the top sheet 30 is fixed to the surface of the intermediate sheet 40 and the surface of the portion of the packaging sheet 58 located on the front side of the absorbent body 56 with a hot-melt adhesive applied to its back surface.

(intermediate sheet)
An intermediate sheet 40 having a faster liquid permeation rate than the top sheet 30 can be provided in order to allow the liquid permeating the top sheet 30 to quickly transfer to the absorbent body. The intermediate sheet 40 not only allows the liquid to quickly transfer to the absorbent body to enhance the absorption performance of the absorbent body, but also prevents the absorbed liquid from returning from the absorbent body. The intermediate sheet 40 can also be omitted.

Examples of the intermediate sheet 40 include materials similar to those of the top sheet 30, spunlace nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, pulp nonwoven fabric, mixed sheet of pulp and rayon, pointbond nonwoven fabric, and crepe paper. In particular, an air-through nonwoven fabric is preferred because it is bulky. Composite fibers having a core-sheath structure are preferably used for the air-through nonwoven fabric. In this case, the resin used for the core may be polypropylene (PP), but polyester (PET) having high rigidity is preferable. The basis weight is preferably 20-80 g/m ² , more preferably 25-60 g/m ² . The fiber thickness of the nonwoven fabric is preferably 2.0 to 10 dtex. In order to make the nonwoven fabric bulky, it is also preferable to use eccentric fibers, hollow fibers, or eccentric and hollow fibers with no core in the center as mixed fibers of all or part of the fibers.

The intermediate sheet 40 in the illustrated example is shorter than the width of the absorbent body 56 and arranged in the center, but it may be provided over the entire width. The longitudinal length of the intermediate sheet 40 may be the same as the length of the absorbent body 56, or may be within a shorter length range centered on the liquid-receiving area.

The intermediate sheet 40 is desirably fixed to a member adjacent to the back side by means of material welding such as heat sealing or ultrasonic sealing, or hot-melt adhesive for the purpose of preventing misalignment with respect to the member on the back side. In the illustrated example, the intermediate sheet 40 is fixed to the surface of the portion of the packaging sheet 58 located on the front side of the absorbent body 56 with a hot-melt adhesive applied to its back surface.

(liquid-impermeable sheet)
The material of the liquid-impermeable sheet 11 is not particularly limited, but examples thereof include a plastic film made of an olefin resin such as polyethylene or polypropylene, a laminated nonwoven fabric in which a plastic film is provided on the surface of a nonwoven fabric, and a laminated sheet in which a nonwoven fabric or the like is laminated and bonded to a plastic film. For the liquid-impermeable sheet 11, it is preferable to use a liquid-impermeable and moisture-permeable material that is preferably used from the viewpoint of preventing stuffiness. As a plastic film having moisture permeability, a microporous plastic film obtained by kneading an inorganic filler into an olefin resin such as polyethylene or polypropylene, forming a sheet, and stretching the sheet in a uniaxial or biaxial direction is widely used. In addition, a liquid-impermeable sheet without using a plastic film, such as a nonwoven fabric coated with a water-repellent agent using microdenier fibers, can also be used as the liquid-impermeable sheet 11 .

The liquid-impermeable sheet 11 has a width that can be accommodated on the back side of the absorbent element 50 as shown in the figure, and can also be wrapped around both sides of the absorbent element 50 to extend to both sides of the top sheet 30 of the absorbent element 50 in order to improve leakproofness.

(Getting up gathers)
The rising gathers 60 are belt-like members extending along both sides of the inner body 200 over the entire front-rear direction, and are provided to block excrement moving laterally along the top sheet 30 and prevent lateral leakage. The rising gathers 60 of this example are provided so as to stand up from the side part of the inner body 200, the part on the base side stands obliquely toward the center side in the width direction WD, and the part on the tip side from the intermediate part stands obliquely outside in the width direction WD.

More specifically, the riser gathers 60 are formed by folding a belt-shaped gather sheet 62 having a length equal to the length of the inner body 200 in the front-rear direction in the width direction WD and folding it in two, and fixing a plurality of elongated gather elastic members 63 between the folded portions and the sheets in the vicinity thereof in a longitudinally stretched state at intervals in the width direction WD. A base end portion of the rising gathers 60 located on the opposite side to the tip portion (an end portion on the side opposite to the sheet folded portion in the width direction WD) is a mounting portion 65 fixed to the rear surface of the side edge portion of the inner body 200, and the portion other than the mounting portion 65 is a protruding portion 66 (a portion on the folded portion side) protruding from the mounting portion 65. - 特許庁The projecting portion 66 is composed of a root side portion directed toward the center in the width direction WD and a tip side portion folded back from the tip of the root side portion to the outside in the width direction WD. This is a surface contact type rising gather, but a line contact type rising gather (not shown) that is not folded outward in the width direction WD can also be employed. Both ends of the protruding portion 66 in the front-rear direction are fixed to the side surface of the top sheet 30 in the laid down state, while the front-rear intermediate portion positioned between them is the unfixed free portion 68. A gather elastic member 63 along the front-rear direction is fixed to the free portion 68 in a stretched state.

At the free portion 68 of the rising gather 60, at least one of hot-melt adhesive by various coating methods and fixing means by material welding such as heat sealing and ultrasonic sealing can be used for bonding the inner layer and the outer layer of the gather sheet 62 and fixing the gathered elastic member 63 sandwiched between them. If the inner layer and the outer layer of the gather sheet 62 are entirely adhered together, the flexibility is impaired. Therefore, it is preferable that the gather elastic member 63 is not adhered or adhered weakly except for the adhered portion. In the illustrated example, the hot-melt adhesive is applied only to the outer peripheral surface of the gathers elastic member 63 by an application means such as a comb gun or a sure wrap nozzle, and is sandwiched between the inner layer and the outer layer of the gathers sheet 62, thereby fixing the gathers elastic member 63 to the inner layer and the outer layer of the gathers sheet 62 and fixing the inner layer and the outer layer of the gathers sheet 62 only with the hot-melt adhesive applied to the outer peripheral surface of the gathers elastic member 63.

In addition, for fixing the waterproof film 64 incorporated in the rising gather 60 and the gather sheet 62, and fixing the front and rear fixing part 67 to the side surface of the inner body 200, at least one of hot melt adhesive by various coating methods and means by welding the material 63 such as heat sealing and ultrasonic sealing can be used. In the illustrated example, a slot application of hot melt adhesive is used to secure the waterproof film 64 . In addition, although the hot-melt adhesive and material welding are combined to fix the front and rear fixing portions 67 in the illustrated example, it is also possible to use only one of these means for fixing.

As the gather sheet 62, nonwoven fabrics such as spunbond nonwoven fabrics (SS, SSS, etc.), SMS nonwoven fabrics (SMS, SSMMS, etc.), meltblown nonwoven fabrics, etc., which are flexible and excellent in uniformity and hiding properties, and optionally water-repellent treated with silicone or the like can be suitably used, and the fiber basis weight is preferably about 10 to 30 g / m ² . Thread rubber or the like can be used as the gathering elastic member. When spandex thread rubber is used, the thickness is preferably 470 to 1240 dtex, more preferably 620 to 940 dtex. The elongation rate when fixed is preferably 150 to 350%, more preferably 200 to 300%. Also, as shown in the figure, a waterproof film 64 can be interposed between the gathered sheets folded in two.

The number of gathering elastic members provided in the free portion of the rising gathers 60 is preferably 2-6, more preferably 3-5. A suitable arrangement interval 60d is 3 to 10 mm. With such a configuration, the area where the gathered elastic member is arranged is likely to come into contact with the skin. A gather elastic member may be arranged not only on the tip side but also on the root side.

The fixing target of the mounting portion 65 of the rising gathers 60 can be an appropriate member such as the top sheet 30, the liquid impermeable sheet 11, the absorbent element 50, etc. of the inner body 200. FIG.

In the rising gathers 60 having the above structure, the contractile force of the gather elastic member acts to bring the both ends in the front-rear direction closer together. In particular, when the mounting part 65 is located on the back side of the inner body 200, the rising gathers 60 stand up to open outward in the width direction WD in the crotch part and its vicinity, so that the rising gathers 60 come to abut on the circumference of the leg with a surface, and the fitting property is improved.

(absorbing element)
The absorbent element 50 has an absorbent body 56 and a wrapping sheet 58 that wraps the entire absorbent body 56 . The packaging sheet 58 can also be omitted.

(Absorber)
Absorbent body 56 can be formed from an aggregate of fibers. As the fiber aggregate, a filament aggregate obtained by piling short fibers such as cotton pulp and synthetic fibers, or by opening a tow (fiber bundle) of synthetic fibers such as cellulose acetate as necessary, can be used. The fiber basis weight can be, for example, about 100 to 300 g/m ² in the case of laminating cotton pulp or short fibers, and can be, for example, about 30 to 120 g/m ² in the case of a filament assembly. The fineness of synthetic fibers is, for example, 1 to 16 dtex, preferably 1 to 10 dtex, more preferably 1 to 5 dtex. In the case of a filament assembly, the filaments may be non-crimped fibers, but crimped fibers are preferred. The degree of crimping of the crimped fibers can be, for example, about 5 to 75, preferably 10 to 50, more preferably 15 to 50 per 2.54 cm. Further, uniformly crimped crimped fibers can be used. It is preferable to disperse and hold superabsorbent polymer particles in the absorbent body 56 .

The absorbent body 56 may have a rectangular shape, but as shown in FIGS. 1 and 2, it is preferable to have an hourglass shape having a front end, a rear end, and a constricted portion positioned between them and narrower than the front end and the rear end, because the fit of the absorbent body 56 itself and the sit-up gathers 60 around the legs is improved.

The size of the absorbent body 56 can be determined as appropriate as long as it spans the front, rear, left, and right of the urination opening position, but it preferably extends to the peripheral edge of the inner body or its vicinity in the front, rear, and width directions WD. The reference numeral 56X indicates the width of the absorber 56. As shown in FIG.

(superabsorbent polymer particles)
Absorbent body 56 may contain superabsorbent polymer particles in part or in its entirety. Superabsorbent polymer particles include "powder" in addition to "particles". As the superabsorbent polymer particles, those used in this type of disposable diaper can be used as they are. For example, after sieving with a standard sieve of 500 μm (JIS Z8801-1:2006) (shaking for 5 minutes), it is desirable that the percentage of particles remaining on the sieve is 30% by weight or less, and sieving with a standard sieve of 180 μm (JIS Z8801-1:2006) (shaking for 5 minutes). It is desirable that the ratio of particles remaining on the sieve is 60% by weight or more.

Materials for the superabsorbent polymer particles may be used without any particular limitation, but those having a water absorption of 40 g/g or more are suitable. Examples of superabsorbent polymer particles include starch-based, cellulose-based, and synthetic polymer-based particles, and starch-acrylic acid (salt) graft copolymers, starch-acrylonitrile copolymer saponified products, crosslinked products of sodium carboxymethyl cellulose, acrylic acid (salt) polymers, and the like can be used. As for the shape of the superabsorbent polymer particles, the powder particles that are commonly used are suitable, but other shapes can also be used.

As the superabsorbent polymer particles, those having a water absorption rate of 70 seconds or less, particularly 40 seconds or less are preferably used. If the water absorption rate is too slow, the liquid supplied into the absorbent body 56 tends to return to the outside of the absorbent body 56, which is called reversion.

As the superabsorbent polymer particles, those having a gel strength of 1000 Pa or more are preferably used. As a result, even when the absorbent body 56 is bulky, it is possible to effectively suppress the feeling of stickiness after liquid absorption.

The basis weight of the superabsorbent polymer particles can be appropriately determined according to the absorption amount required for the use of the absorbent body 56 . Therefore, although it cannot be generalized, it can be 50 to 350 g/m ² . If the basis weight of the polymer is less than 50 g/m ² , it becomes difficult to secure the absorption capacity. Above 350 g/m ² , the effect saturates.

If necessary, the superabsorbent polymer particles can be adjusted in the planar direction of the absorbent body 56 in the distribution density or distribution amount. For example, the liquid excretion site can be sprayed with a larger amount than other sites. In consideration of gender differences, it is possible to increase the spraying density (amount) in the front for men and to increase the spraying density (amount) in the center for women. Moreover, it is also possible to provide a portion where the polymer does not exist locally (for example, spot-like) in the planar direction of the absorbent body 56 .

(packaging sheet)
When the packaging sheet 58 is used, tissue paper, especially crepe paper, non-woven fabric, poly-laminated non-woven fabric, a perforated sheet, or the like can be used as the material. However, it is desirable that the sheet is such that the superabsorbent polymer particles do not escape. When non-woven fabric is used instead of crepe paper, hydrophilic SMS non-woven fabric (SMS, SSMMS, etc.) is particularly suitable, and its material can be polypropylene, polyethylene/polypropylene composite, or the like. The basis weight is preferably 5 to 40 g/m ² , particularly 10 to 30 g/m ² .

The packaging structure of the packaging sheet 58 can be determined as appropriate, but from the viewpoint of ease of manufacture and prevention of leakage of the superabsorbent polymer particles from the front and back edges, etc., it is preferable to have a structure in which the absorbent body 56 is cylindrically wound so as to surround the front and back surfaces and both side surfaces, the front and rear edges protrude from the front and back of the absorbent body 56, and the overlapping portion and the overlapping portion of the front and rear protruding portions are joined by a joining means such as hot melt adhesive or material welding.

(Exterior body)
The exterior bodies 12F and 12B are composed of a front exterior body 12F constituting a front body F and a rear exterior body 12B constituting a back body B, and the front exterior body 12F and the rear exterior body 12B are not continuous on the crotch side and are spaced apart in the front-rear direction. This separation distance 12d can be about 150 to 250 mm. An interior cover sheet 12M made of a non-woven fabric or the like is preferably attached so as to cover a part of the exposed portion of the rear surface of the interior body 200 in this spaced portion (for example, the exposed portion between the front exterior body 12F and the rear exterior body 12B extends in the front-rear direction, but does not extend to the front and rear ends of the interior body 200, and the side edges do not reach both side edges of the interior body 200), but it can be omitted. Alternatively, as shown in FIG. 8, the outer body 12 may be an integral body extending from the front body F to the back body B through the crotch.

The outer bodies 12F and 12B have a waist portion corresponding to the waist region T in the front-rear direction. Also, in this example, the front exterior body 12F does not have a portion corresponding to the intermediate region L, but the rear exterior body 12B has a buttock cover portion 14 extending from the waist region T toward the intermediate region L side. Although not shown, the front exterior body 12F may also be provided with an inguinal cover portion extending from the waist region T to the intermediate region L side, or a structure may be provided in which the groin cover portion is provided but the buttocks cover portion is not provided, or neither the front exterior body 12F nor the rear exterior body 12B may be provided with a portion corresponding to the intermediate region L. In the illustrated example, the lower edge of the buttock cover portion 14 is formed in a straight line along the width direction WD, like the lower edge of the front exterior body 12F.

As shown in FIGS. 3 to 5, the exterior bodies 12F and 12B are formed by joining the outer sheet layer 12S and the inner sheet layer 12H with a joining means such as hot-melt adhesive or welding. The sheet material forming the outer sheet layer 12S and the sheet material forming the inner sheet layer 12H may be individual sheet materials as in the example shown in FIG. 5, or may be a common sheet material as in the example shown in FIG. That is, in the latter case, the inner sheet layer 12H and the outer sheet layer 12S are formed by the inner portion and the outer portion of one sheet material folded back at the waist side edge (or the crotch side edge). The former example has the advantage that the inner sheet layer 12H and the outer sheet layer 12S are less likely to be misaligned when the inner sheet layer 12H and the outer sheet layer 12S are stuck together because the number of folding steps of the sheet material is small, and the latter example has the advantage that the number of sheet materials is small.

If the ends of the sheet material forming the outer sheet layer 12S and the inner sheet layer 12H and the front and rear ends of the inner body 200 are exposed to the waist opening WO, there is a risk that the corners of the sheet material will touch the skin, deteriorating the feel of the skin, or that the waist part W elastic member described later and the hot-melt adhesive for fixing it will be exposed. Therefore, as in the example shown in FIG. 5, it is preferable that the sheet material forming the outer sheet layer 12S is wrapped around the waist-side edge of the sheet material forming the inner sheet layer 12H and folded inward to form an inner layer, and the inner layer 12r extends over the waist-side end of the inner body 200.

The sheet material used for the outer sheet layer 12S and the inner sheet layer 12H is not particularly limited, but for example, various nonwoven fabrics made of thermoplastic resins can be suitably used. When a non-woven fabric is used, it is preferable that its basis weight is about 10 to 30 g/m ² .

(stretch area)
In the illustrated example of the exterior bodies 12F and 12B, elongated elastic members 15 to 18 such as rubber threads are attached at a predetermined elongation rate between the outer sheet layer 12S and the inner sheet layer 12H in order to improve the fit around the wearer's waist. As the elastic members 15-18, either synthetic rubber or natural rubber may be used.

In the elastic region A2, the inner sheet layer 12H and the outer sheet layer 12S are joined by the hot melt adhesive H1 disposed at least at the positions of the elastic members 15 to 18, and the elastic members 15 to 18 are fixed to the inner sheet layer 12H and the outer sheet layer 12S. Therefore, as shown in FIG. 2, the fixing of the elastic members 15 to 18 to the inner sheet layer 12H and the outer sheet layer 12S in the elastic region A2 may be performed only by the hot melt adhesive H1 placed at the positions of the elastic members 15 to 18. This structure can be manufactured by applying the hot melt adhesive H1 to the outer peripheral surfaces of the elastic members 15 to 18 by means of an application means such as a comb gun or Surewrap nozzle, without applying the hot melt adhesive H1 to the inner sheet layer 12H and the outer sheet layer 12S, and sandwiching it between the two sheet layers 12S and 12H. As shown in FIG. 8, a hot-melt adhesive H2 for reinforcement may be added to both ends of the elastic region A2 in the width direction WD. In the example shown in FIG. 8, the hot melt adhesive H2 for reinforcement is applied to both ends of the elastic region of either the inner sheet layer 12H or the outer sheet layer 12S by slot coating or pattern coating (transfer of the hot melt adhesive by letterpress method), and the hot melt adhesive H1 is applied only to the outer peripheral surface of the elastic members 15 to 18 by applying means such as a comb gun or sure wrap nozzle, and is sandwiched between the sheet layers 12S and 12H. can be

The arrangement of the elastic members 15 to 18 is not particularly limited as long as the elastic region A1 is provided. That is, between the outer sheet layer 12S and the inner sheet layer 12H in the waist portion W of the exterior bodies 12F and 12B, a plurality of waist elastic members 18 are attached so as to be continuous over the entire width direction WD while being spaced in the front-rear direction and being stretched along the width direction WD at a predetermined elongation rate. In addition, one or more of the waist elastic members 18 disposed in the region adjacent to the lower waist portion U may overlap the interior body 200, or may be provided on both sides of the interior body 200 except for the central portion in the width direction WD overlapping the interior body 200. As the waist elastic member 18, about 3 to 22 rubber threads having a thickness of 155 to 1880 dtex, particularly about 470 to 1240 dtex (in the case of synthetic rubber such as spandex, and a cross-sectional area of 0.05 to 1.5 mm ² , particularly about 0.1 to 1.0 mm ² in the case of natural rubber) are arranged at intervals of 4 to 12 mm, and each has an elongation rate of 150 to 400%, particularly 220 to 320%. It is preferable to attach it by degree. Moreover, the waist elastic members 18 do not have to all have the same thickness and elongation rate, and for example, the upper and lower portions of the waist portion W may have different thicknesses and elongation rates.

In addition, a plurality of lower waist elastic members 15 and 17 made of elastic members are attached between the outer sheet layer 12S and the inner sheet layer 12H in the lower waist portion U of the outer bodies 12F and 12B, spaced apart in the front-rear direction, and stretched along the width direction WD at a predetermined elongation rate.

As the waist lower elastic members 15 and 17, thread rubber having a thickness of 155 to 1880 dtex, particularly about 470 to 1240 dtex (in the case of synthetic rubber; in the case of natural rubber, a cross-sectional area of 0.05 to 1.5 mm ² , particularly about 0.1 to 1.0 mm ² ) is arranged at intervals of 1 to 15 mm, particularly 3 to 8 mm, and about 5 to 30 threads, each having an elongation rate of 200 to 350%, particularly 240. It is preferable to attach it at about 300%.

In addition, a plurality of cover section elastic members 16 made of elastic members are attached between the outer sheet layer 12S and the inner sheet layer 12H of the buttock cover section 14 of the rear exterior body 12B, spaced apart in the front-rear direction, and in a state of being stretched along the width direction WD at a predetermined elongation rate.

As the elastic member 16 of the cover part, thread rubber having a thickness of 155 to 1880 dtex, particularly about 470 to 1240 dtex (in the case of synthetic rubber; in the case of natural rubber, a cross-sectional area of 0.05 to 1.5 mm ² , particularly about 0.1 to 1.0 mm ² ) is used. It is preferred to install at 0%.

When a groin cover portion is provided on the front side exterior body 12F, a cover portion elastic member can be similarly provided.

(Non-stretch area)
When the elastic members 15 to 17 are provided in the front-rear range having the absorbent body 56, such as the lower waist portion U and the buttocks cover part 14 in the illustrated example, in order to prevent contraction of the absorbent body 56 in the width direction WD in part or all thereof, the middle of the width direction WD (preferably including the entire inner/outer fixed part 201) in the front-rear direction range having the absorbent body 56, including part or all of the portion overlapping the absorbent body 56 in the width direction WD, is defined as the non-stretchable region A1. It is preferable that both sides in the width direction WD are formed as stretchable regions A2 over the entire width direction WD.

The non-stretchable region A1 is a region having an inner sheet layer 12H and an outer sheet layer 12S continuous from the stretchable region A2, and an independent shrinkable portion 19 continuous from the elastic members 15 to 17 of the stretchable region A2 interposed between the inner sheet layer 12H and the outer sheet layer 12S. The independently contracted portion 19 is a portion of the elastic members 15-17 that contract without the inner sheet layer 12H and the outer sheet layer 12S. In the non-stretchable region A1, it is preferable that the inner sheet layer 12H and the outer sheet layer 12S are not joined and the independently shrinkable portion 19 is not fixed to the inner sheet layer 12H and the outer sheet layer 12S in order to form the independently shrinkable portion 19. Of course, the inner sheet layer 12H and the outer sheet layer 12S may be joined weaker than the stretchable region A2 only by the hot melt adhesive placed at the position of the independent shrinkable portion 19, and the independent shrinkable portion 19 may be fixed to the inner sheet layer 12H and the outer sheet layer 12S weaker than the elastic members 15 to 17 of the stretchable region A2. Therefore, the amount of hot-melt adhesive applied to the independent contraction portion 19 can be made smaller than the amount of hot-melt adhesive applied to the elastic region A2.

The non-stretchable region A1 preferably has a reinforcing joint 23 where the inner sheet layer 12H and the outer sheet layer 12S are directly welded in at least one location including the central portion in both the width direction WD and the front-rear direction LD. The reinforced joint 23 reinforces the joint between the inner sheet layer 12H and the outer sheet layer 12S in the non-stretchable region A1, thereby preventing the outer sheet layer 12S from floating from the inner sheet layer 12H and the outer sheet layer 12S from irregular and large wrinkles, thereby reducing the possibility of deteriorating the appearance.

The shape and arrangement of the reinforcing joints 23 in the non-stretchable region A1 can be appropriately determined. The shape of the reinforcing joints 23 can be, for example, a dotted line shape as shown in FIGS. 9 and 11, a continuous line shape as shown in FIG. 12, or a dot arrangement such as a zigzag shape as shown in FIG. It is preferable that the reinforcing joints 23 are arranged intermittently in at least one of the longitudinal direction LD and the width direction WD. 9 and 10, it is preferable to dispose the reinforcing joints 23 uniformly over the entire longitudinal direction LD and the width direction WD in the non-stretchable region A1. However, the reinforcing joints 23 may be provided only at one place in the width direction WD (FIG. 12) over the entire longitudinal direction LD, or, although not shown, may be provided only at the central portion in both the width direction WD and the longitudinal direction LD.

When the reinforcing joints 23 are arranged in a dot array or a dotted line, the individual reinforcing joints 23 may have any shape such as a perfect circle, an ellipse, a triangle, a rectangle, a polygon such as a rhombus, a star, a cloud, or the like. In this case, the dimensions of the individual reinforcing joints 23 are not particularly limited, but the maximum dimension in the front-rear direction LD is preferably 0.5 to 4 mm, particularly 1 to 3 mm, and the maximum dimension in the width direction WD is 0.5 to 4 mm, particularly preferably 1 to 3 mm. The interval in the front-rear direction LD is preferably 2 to 5 mm, especially 3 to 5 mm, and the interval in the width direction WD is preferably 0.5 to 4 mm, especially 1 to 3 mm.

For example, as shown in FIG. 9, it is preferable that the reinforcing joints 23 are provided along the width direction WD in a dotted line or a line at intervals between the independent contraction portions 19 adjacent to each other in the front-rear direction LD. In this case, it is preferable that the reinforcing joints 23 are arranged at each of the gaps, and more preferably, the reinforcing joints 23 are arranged at both ends of the non-stretchable region A1 in the front-rear direction LD. The reinforcing joints 23 may be arranged only in a part of the spaced portion (for example, only in the central portion in the front-rear direction LD or every other part in the front-rear direction LD). As a result, even if the independent contraction portions 19 of the elastic members 15 to 17 move in the front-rear direction LD, the movement is restricted by the reinforcing joints 23, so that they do not cross the other independent contraction portions 19 adjacent in the front-rear direction LD. Therefore, it is possible to prevent deterioration of the appearance due to irregular shapes of the independent contraction portions 19 of the elastic members 15 to 17 .

Although not shown, the reinforcing joint 23 may be provided in the form of a pattern, a picture (including characters), letters (function indications such as usage, usage assistance, size, etc., or indications such as mark indications such as manufacturer, product name, characteristic functions, etc.), or a combination of these. Thereby, the designability of the non-stretchable region A1 can be improved.

9 and 10, the independent contraction portion 19 may be continuous from the elastic members 15 to 17 of the stretchable region A2 on one side in the width direction WD only, or as shown in FIGS. Although not shown, the elastic members 15 to 17 of the stretchable region A2 on one side in the width direction WD and the elastic members 15 to 17 of the stretchable region A2 on the other side in the width direction WD may alternately exist in the front-rear direction LD.

As shown in FIGS. 11 and 12, when the lengths of the independent contraction portions 19 on both sides in the width direction WD are equal, the appearance becomes bilaterally symmetrical with respect to the center in the width direction WD, which is preferable in terms of aesthetic appearance. Of course, as in the examples shown in FIGS. 9 and 10, the lengths of the independent contraction portions 19 on both sides in the width direction WD may be different.

When forming the outer body 12 in the manufacture of the pants-type disposable diaper, as shown in FIG. 14, the elongated elastic members 15 to 18 are continuously stretched in the longitudinal direction between the inner sheet layer 12H and the outer sheet layer 12S so as to pass through the stretchable region A2 and the non-stretchable region A1. At this time, in the stretchable region A2, the inner sheet layer 12H and the outer sheet layer 12S are joined via the hot melt adhesive H1 applied to the peripheral surfaces of the elastic members 15 to 18, and the elastic members 15 to 18 are fixed to the inner sheet layer 12H and the outer sheet layer 12S. Also, in the non-stretchable region A1, the inner sheet layer 12H and the outer sheet layer 12S are not joined, and the independently shrinkable portion 19 is not fixed to the inner sheet layer 12H and the outer sheet layer 12S. In the non-stretchable region A1, the inner sheet layer 12H and the outer sheet layer 12S may be joined weaker than the stretchable region A2 only by the hot melt adhesive applied to the peripheral surfaces of the elastic members 15 to 17, and the elastic members 15 to 17 may be fixed to the inner sheet layer 12H and the outer sheet layer 12S weaker than the stretchable region A2.

After that, the elastic members 15 to 17 are cut by pressing and heating while sandwiching from the inner side of the inner sheet layer 12H and the outer side of the outer sheet layer 12S at one point in the width direction WD of the non-stretchable area A1. As a result of this cutting, cut traces 22 (compression traces and melting traces) are left in the pressurized and heated portions of the product. In addition, since the elastic members 15 to 18 remaining in the non-stretchable region A1 are not fixed (or weakly fixed) to the inner sheet layer and the outer sheet layer, they move with respect to the inner sheet layer 12H and the outer sheet layer 12S while contracting.

Although not shown, separately manufactured inner bodies are sequentially attached to the continuous body of the outer bodies 12F and 12B thus formed, and after the front and back are folded so as to overlap each other, side seal portions 12A are formed on both sides of the boundaries of the parts to be individual diapers, and further cutting is performed at the boundaries, whereby a pants-type disposable diaper can be manufactured.

FIG. 13 shows a step of cutting the elastic members 15 to 17 in the formation of the exterior bodies 12F and 12B. The display sheet 25 and the elastic members 15 to 18 are attached between the inner sheet layer 12H and the outer sheet layer 12S by means of a seal roll 70 having a pressing portion 71 having cutting convex portions 72 formed in a predetermined cutting pattern on the outer peripheral surface thereof, the cutting convex portions 72 being heated to a desired temperature, and an anvil roll 80 having a smooth surface arranged opposite to the sealing roll 70. The object to be cut is sandwiched so that the inner sheet layer 12H is on the seal roll side (or the opposite side), and only the portion sandwiched between the cutting convex portion 72 and the outer peripheral surface of the anvil roll 80 is cut by applying pressure and heat to the elastic members 15 to 17. The heating temperature for cutting the elastic members 15 to 17 (the temperature of the cutting protrusions) may be appropriately determined as long as the elastic members 15 to 17 can be reliably cut. However, in order to reliably cut the elastic members 15 to 17, prevent the cut portions of the elastic members 15 to 17 from adhering to the surrounding members, and weld the outer sheet layer 12S and the inner sheet layer 12H at the cutting positions, the temperature must be lower than the melting point of the elastic members 15 to 17. A sufficiently high temperature is preferable. For example, when the melting point of the nonwoven fabric used for the outer sheet layer 12S and the inner sheet layer 12H is about 160 to 175°C and the melting point of the elastic members 15 to 17 is about 200 to 230°C, the heating temperature can be 180 to 200°C.

The cutting position (the position of the cutting trace 22) is not particularly limited as long as it is one point in the width direction WD of the non-stretchable region A1, and may be either one end in the width direction WD of the non-stretchable region A1 as shown in FIGS. The location of the cut will determine the length and placement of the independent retraction portion 19 .

The width of the cutting protrusion 72 (the dimension in the width direction WD of the cut trace 22) can be determined as appropriate, but it is preferably about 0.5 to 8% of the dimension in the width direction WD of the non-stretchable region A1, or about 0.5 to 5 mm.

The cutting pattern (cutting trace 22) is not particularly limited, and may be an intermittent pattern in the front-rear direction LD as shown in FIG. Such a linear pattern may be a linear pattern as shown in the drawing, or may be a curved or wavy pattern (not shown).

The reinforcing joint portion 23 can be formed by sandwiching the inner sheet layer 12H and the outer side of the outer sheet layer 12S from the inner side of the inner sheet layer 12H and the outer side of the outer sheet layer 12S and applying pressure and heat to weld the inner sheet layer 12H and the outer sheet layer 12S. For example, as in the example shown in FIGS. 13 and 14 (a) to (c), the sealing roll 70 having the cutting convex portion 72 of the elastic members 15 to 17 is formed with a welding convex portion 73 for forming the reinforcing joint portion 23. It is preferable because a single seal roll 70 can cut the elastic members 15 to 17 and form the reinforcing joint portion 23, which simplifies the manufacturing facility. Of course, when the appropriate heating temperature for cutting the elastic members 15 to 17 differs from the appropriate heating temperature for forming the reinforcing joint 23, as shown in FIG. The formation of the reinforcing joint 23 may be performed after the elastic members 15 to 17 are cut, as shown in FIGS. 13 and 14(a), before the elastic members 15 to 17 are cut, as shown in FIGS.

If the reinforcing joints 23 are formed before or simultaneously with the cutting of the elastic members 15-17, the elastic members 15-17 may be pressurized and heated. Therefore, for example, as in the example shown in FIG. 11, after cutting the elastic members 15 to 17 at the middle portion (cutting trace 22) in the width direction WD of the non-stretchable region A1, it is preferable to form the reinforcing joints 23 in the range in the width direction WD that does not have the independently contracting portions 19, such as forming the reinforcing joints 23 at positions between the independently contracting portions 19 located on both sides in the width direction WD.

When the cutting of the elastic members 15 to 17 and the formation of the reinforcing joint 23 are performed at the same time, if they are simultaneously performed only in the central portion of the non-stretchable region A1 in the width direction WD, the cutting trace 22 and the reinforcing joint 23 are provided only in the central portion of the non-stretchable region A1 in the width direction WD, and the lengths of the independent contraction portions 19 on both sides in the width direction WD are equal. Therefore, the appearance including the reinforcing joint portion 23 is left-right symmetrical about the center in the width direction WD, which is preferable in terms of excellent aesthetic appearance.

When the reinforcing joints 23 are formed before cutting the elastic members 15 to 17, as shown in FIG. 9, it is preferable to form the reinforcing joints 23 along the width direction WD between the independently contracting portions 19 adjacent to each other in the front-rear direction LD so that the independently contracting portions 19 are less likely to have an irregular shape when the independently contracting portions 19 contract after cutting.

(post-treatment tape)
As shown in FIGS. 2 and 8, a post-treatment tape 90 is provided on the outer surface of the non-stretchable region A1 of the rear exterior body 12B. That is, as shown in FIGS. 15 and 16, the post-treatment tape 90 has a belt-shaped root portion 91 that extends in the front-rear direction LD and is fixed to the outer surface of the outer sheet layer 12S of the exterior body 12 with an adhesive 94 or the like, belt-shaped body portions 92 and 93 that extend from the waist side of the root portion 91, and an adhesive 94 provided on the body portions 92 and 93. When disposing of the diaper, after the diaper is rolled or folded so that the top sheet 30 is on the inside and the front body F is on the inside, the main body parts 92 and 93 of the post-treatment tape 90 are peeled off, and then the main body parts 92 and 93 are wound from the back body B of the rolled or folded diaper 100 to the opposite outer surface beyond the waist opening WO as shown in FIG. This allows the diaper to be fixed in a rolled or folded state as shown in FIG.

The body portions 92 and 93 of the post-treatment tape 90 have a first portion 92 extending from the waist opening WO side of the root portion 91 to the crotch side, and a second portion 93 folded back toward the waist opening WO side at the tip of the first portion 92. An adhesive 94 is provided on a surface of the first portion 92 facing the root portion 91 and a surface of the second portion 93 facing the first portion 92, respectively. Preferably, the first portion 92 and the second portion 93 are fixed in the folded state by adhering the root portion 91 with the adhesive 94 and the second portion 93 with the adhesive 94 on the first portion 92 . In this case, the base portion 91 and the body portions 92, 93 may be formed by connecting a plurality of sheets S1 to S4 as shown in the figure, or may be formed by a single sheet (not shown). When the base portion 91 is formed by connecting a plurality of sheets, the number of sheets is not particularly limited, and although it is composed of four sheets in the illustrated example, it can be composed of fewer or more sheets than these. When post-processing is performed, the front ends of the body parts 92 and 93 are pinched and pulled in the direction away from the exterior body 12 or toward the waist opening WO side, so that the first part 92 and the second part 93 are peeled off in order as shown in FIG. When the body portions 92 and 93 are laid down toward the waist opening WO side at the same time as or after deployment, the adhesive of the second portion 93 faces the exterior body 12 .

More specifically, the post-processing tape 90 has an adhesive 94 applied to the surface facing the exterior body 12. A first sheet S1 is fixed to the outer surface of the exterior body 12 by the adhesive 94, a second sheet S2 is connected to the leading end of the first sheet S1 folded outward, and a third sheet S3 is secured to the leading end folded outward of the second sheet S2. At the same time, the second sheet S2 is detachably adhered to the first sheet S1 by the adhesive 94 applied to the surface on the first sheet S1 side, and the third sheet S3 is detachably adhered to the second sheet S2 by the adhesive 94 applied to the surface on the second sheet S2 side. The surface of each of the sheets S1 to S3 on the side opposite to the side of the adhesive 94 is subjected to a peeling process using a release agent or the like so that it can be peeled off. A colored tape S4 colored in an opaque color such as white is connected to the leading end of the third sheet S3 with an adhesive 94 to form a knob portion with good visibility (in the illustrated example, the leading end of a single sheet is colored in an opaque color different from that of the other portions).

The dimensions of the post-treatment tape 90 are not particularly limited, but considering the ease of picking, the stability when the diaper is fixed in a rolled state, the feeling of wearing, etc., the dimension 91W in the width direction WD of the main body portions 92, 93 and the base portion 91 is about 11 to 15 mm, the dimension 91L in the front-back direction LD of the base portion 91 is about 0.1 to 0.2 times the total length Y of the diaper, and the length in the front-back direction LD in the unfolded state of the main body portions 92, 93. The dimension 90L is preferably about 1.4 to 1.7 times the dimension 91L of the base portion 91 in the front-rear direction LD.

As the material for the base portion 91 and the main portions 92 and 93, for example, olefin resin such as polyethylene and polypropylene, and synthetic resin sheets such as polyvinyl chloride and PET can be suitably used, but the material is not particularly limited.

The adhesive 94 is not particularly limited, and a synthetic rubber-based adhesive, a natural rubber-based adhesive, an acrylic resin-based adhesive, a silicone resin-based adhesive, or the like can be used.

Other known post-processing tapes 90 may be employed as long as they have root portions 91 and body portions 92 and 93 . Also, the mounting position of the post-processing tape 90 is not particularly limited as long as it is on the outer surface of the exterior body 12, and it can be provided at an appropriate position. Although the post-treatment tape 90 is generally provided on the back body B as shown in the figure, it may be provided on the front body F, or may be provided on both the back body B and the front body F.

In general, the root portion of the post-treatment tape 90 is fixed to the non-stretchable region A1, so that the force that causes the rolled up diaper to expand acts to peel off the root portion and the adhesive portion after application. Therefore, if the bonding between the outer sheet layer 12S and the inner sheet layer 12H in the non-stretchable region A1 is weak or absent, the force that causes the rolled diaper to spread is locally applied only to the outer sheet layer 12S, and the outer sheet layer 12S may stretch or break. Therefore, from this point of view as well, it is preferable to provide the aforementioned reinforcing joint 23 .

<Description of terms in the specification>
The following terms in the specification have the following meanings unless otherwise specified in the specification.

・"Front and back direction" means the direction (vertical direction) indicated by symbol LD in the figure, and "width direction" means the direction (left and right direction) indicated by WD in the figure, and the front and back direction and the width direction are orthogonal.

・"MD direction" and "CD direction" mean the flow direction (MD direction) and the transverse direction (CD direction) perpendicular to this in the manufacturing equipment, and depending on the part of the product, one of them is the front-back direction, and the other is the width direction. The MD direction of a nonwoven fabric is the direction of fiber orientation of the nonwoven fabric. The fiber orientation is the direction along which the fibers of the nonwoven fabric are aligned. For example, it can be determined by a measurement method according to the fiber orientation test method based on the zero-distance tensile strength of the TAPPI standard method T481, or by a simple measurement method that determines the fiber orientation direction from the tensile strength ratio in the front-back direction and the width direction.

- The "front side" means the side closer to the wearer's skin when the pants-type disposable diaper is worn, and the "back side" means the side farther from the wearer's skin when the pants-type disposable diaper is worn.

・"Front surface" means the side of the member that is closer to the wearer's skin when the pants-type disposable diaper is worn, and the "back side" means the side that is farther from the wearer's skin when the pants-type disposable diaper is worn.

- "Elongation rate" means a value when the natural length is taken as 100%. For example, an elongation rate of 200% is synonymous with an elongation ratio of 2 times.

- "Gel strength" is measured as follows. To 49.0 g of artificial urine (urea: 2 wt%, sodium chloride: 0.8 wt%, calcium chloride dihydrate: 0.03 wt%, magnesium sulfate heptahydrate: 0.08 wt%, and deionized water: 97.09 wt%), 1.0 g of superabsorbent polymer is added and stirred with a stirrer. The resulting gel is left in a thermo-hygrostat at 40° C. and 60% RH for 3 hours, then returned to room temperature, and the gel strength is measured with a card meter (Curdmeter-MAX ME-500, manufactured by I. techno Engineering).

- "Matsuke" is measured as follows. After pre-drying the sample or test piece, it is left in a test room or apparatus under standard conditions (test location: temperature 23±1° C., relative humidity 50±2%) to a constant weight. Pre-drying refers to making a sample or test piece constant weight in an environment at a temperature of 100°C. Fibers with an official moisture content of 0.0% do not need to be pre-dried. Using a sampling template (100 mm x 100 mm), a sample with dimensions of 100 mm x 100 mm is cut from the constant weight specimen. The weight of the sample is measured, multiplied by 100 to calculate the weight per square meter, and used as basis weight.

- "Thickness" is automatically measured using an automatic thickness gauge (KES-G5 handy compression measurement program) under the conditions of a load of 0.098 N/cm ² and a pressurized area of 2 cm ² . The thickness of the perforated nonwoven fabric is measured at portions other than the perforations and the protrusions around them.

・The amount of water absorption is measured according to JIS K7223-1996 "Testing method for water absorption of super absorbent polymer".

・The water absorption rate is defined as "time to end point" when JIS K7224-1996 "Testing method for water absorption rate of superabsorbent polymer" is performed using 2g of superabsorbent polymer and 50g of physiological saline.

- "Unfolded state" means a flat unfolded state without contraction or slack.

・Unless otherwise specified, the dimensions of each part mean the dimensions in the unfolded state, not in the natural length state.

・If there is no description about environmental conditions for testing and measurement, the test and measurement shall be performed in a test room or equipment under standard conditions (test location: temperature 23±1°C, relative humidity 50±2%).

INDUSTRIAL APPLICABILITY The present invention can be used for pants-type disposable diapers such as the above examples.

A1 Non-stretchable region A2 Stretchable region H1 Hot-melt adhesive L Intermediate region LD Front-back direction LO Leg opening T Waist region U Waist lower portion W Waist opening WD Waist opening 11 Liquid-impermeable sheet 12 Exterior body 12A Side seal portion 12B Rear exterior body 12F Front exterior body 12H Inner sheet layer 12S Outer sheet layer 12r Inner layer 14 Buttocks cover 15 to 17 Elastic member 18 Waist elastic member 19 Independent contraction portion 22 Cut trace 23 Reinforcing joint 30 Top sheet 40 Intermediate sheet 50 Absorbent element 56 Absorbent body 58 Wrapping sheet 60 Raised gather 62 Gathered sheet 90 Post-treatment tape 200 Inner body 201 Inside and outside Fixed part.

Claims (3)

An integrated exterior covering from the front body to the back body, or an exterior body provided separately for the front body and the back body;
an inner body including an absorbent attached to the outer body so as to extend from the front body to the back body;
a side seal portion in which both side portions of the exterior body of the front body and both side portions of the exterior body of the back body are respectively joined;
Equipped with a waist opening and a pair of left and right leg openings,
The exterior body has a non-stretchable region provided in the middle in the width direction and stretchable regions provided on both sides in the width direction of the non-stretchable region in the front-back direction range including the absorbent body,
The elastic region has an inner sheet layer, an outer sheet layer, and a plurality of elongated elastic members along the width direction attached between the inner sheet layer and the outer sheet layer at intervals in the front-rear direction.
In the elastic region, the inner sheet layer and the outer sheet layer are joined by a hot melt adhesive placed at least at the position of the elastic member, and the elastic member is fixed to the inner sheet layer and the outer sheet layer,
The non-stretchable region has an inner sheet layer and an outer sheet layer that are continuous from the stretchable region, and an independently shrinkable portion that remains between the inner sheet layer and the outer sheet layer and that is continuous from the elastic member of the stretchable region.
In the non-stretchable region, either the inner sheet layer and the outer sheet layer are not bonded and the independently contractible portion is not fixed to the inner sheet layer and the outer sheet layer, or the inner sheet layer and the outer sheet layer are bonded weaker than the stretchable region, and the independently contractible portion is fixed to the inner sheet layer and the outer sheet layer weaker than the elastic member of the stretchable region only by a hot melt adhesive placed at the position of the independently shrinkable portion.
The non-stretchable region has a first widthwise range having the independently contractible portion, and a second widthwise range over the entire front-rear direction of the non-stretchable region without the independent shrinkable portion and other elastic members.
A method for manufacturing a pants-type disposable diaper;
When forming the exterior body, the elastic member is arranged in a stretched state between the inner sheet layer and the outer sheet layer so as to pass through the portion to be the stretchable region and the portion to be the non-stretchable region,
In the stretchable region, at least the inner sheet layer and the outer sheet layer are joined with a hot-melt adhesive applied to the peripheral surface of the elastic member, and the elastic member is fixed to the inner sheet layer and the outer sheet layer,
In the portion to be the non-stretchable region, either the inner sheet layer and the outer sheet layer are not joined and the independently contractible portion is fixed to the inner sheet layer and the outer sheet layer, or the inner sheet layer and the outer sheet layer are joined weaker than the portion to be the stretchable region only by a hot melt adhesive applied to the peripheral surface of the elastic member, and the elastic member is fixed to the inner sheet layer and the outer sheet layer weaker than the portion to be the stretchable region;
After that, at one point in the width direction of the portion to be the non-stretchable region, the elastic member is cut by sandwiching from the inner side of the inner sheet layer and the outer side of the outer sheet layer and applying pressure and heat,
After cutting the elastic member, in the second width direction range of the portion to be the non-stretchable region, the inner sheet layer and the outer sheet layer are sandwiched from the inside of the inner sheet layer and the outer side of the outer sheet layer and subjected to pressure and heat, thereby welding the inner sheet layer and the outer sheet layer to form the reinforcing joint over the entire front and back direction only in the second width direction range.
A method for manufacturing a pants-type disposable diaper, characterized by: After cutting the elastic member at a widthwise intermediate portion of the non-stretchable region so that the lengths of the independently contractible portions on both sides in the width direction are equal, the reinforcing joint is formed in a second widthwise range located between the independently contractible portions on both sides in the widthwise direction.
The method for manufacturing the underpants-type disposable diaper according to claim 1. The reinforcing joint is provided in a display shape consisting of a pattern, picture, letter, or a combination thereof;
The method for manufacturing the underpants-type disposable diaper according to claim 1 or 2.

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