JP5124187B2 - Stretchable part forming method and apparatus for forming absorbent article - Google Patents

Description

  The present invention relates to a stretchable part forming method in an absorbent article and a forming apparatus therefor.

For example, in a pants-type paper diaper that is an absorbent article, as shown in FIGS. 1 and 2, a shirring S may be formed around the abdomen and waist as an expansion / contraction part in order to add a fitting function (for example, Patent Documents). 1). This shearing S is made by sandwiching elastic elastic members 2, 2,..., Such as thread rubber, with a sheet 1 formed by laminating and fixing two or more breathable / water-repellent nonwoven fabrics, and elastic elastic members 2, 2,. The elastic elastic members 2, 2,... And the sheet 1 are intermittently fixed with an adhesive such as hot melt, and the elastic elastic members 2, 2,. is there. In FIG. 1, WO indicates a waist opening, and LO indicates a leg opening.
As a known technique for fixing the elastic elastic members 2, 2,... To the sheet 1 such as the nonwoven fabric, either the elastic elastic members 2, 2,. In general, an adhesive such as hot melt is applied to both the sheet 1 and then fixed by niping the elastic elastic members 2, 2.
Further, in recent years, an anvil roll (not shown) that is intermittently arranged and is constituted by a protrusion that becomes an adhesive surface, and a heat fusion device (not shown) arranged at a position facing the anvil roll (not shown). In addition, a technique is also introduced in which the sheet 1 is continuously supplied in a state in which the elastic elastic members 2, 2,... Are sandwiched and the sheet 1 and the elastic elastic members 2, 2,. .
JP 2002-172132 A JP 2004-330777 A

However, when a hot melt adhesive is used, the adhesive strength of the adhesive is kept constant, resulting in complicated manufacturing equipment such as temperature control of the adhesive and not being applied to elastic elastic members such as rubber. In addition, since the adhesive is applied to manufacturing equipment such as a pressure roll and a transfer belt, there is a risk of causing machine troubles such as increasing the resistance of the sliding portion of the manufacturing equipment and mixing of foreign substances into the product. In addition, there is a problem that mechanical parts are deteriorated or the ambient temperature is increased by heat (150 to 200 ° C.) for dissolving the hot melt.
On the other hand, an adhesive other than hot melt is not preferable because a volatile solvent is harmful to the human body or it is fluid at room temperature and cannot exhibit sufficient adhesive strength.
Moreover, when a stretchable part is formed by fixing an elastic stretchable member and a nonwoven fabric with an adhesive as a product of a paper diaper, there is a problem that the breathability and softness of the stretchable part are lost. Moreover, in the method of fixing in the pinched state of the invention described in Patent Document 2, there is a problem that the elastic stretchable member such as rubber is deteriorated, and the strength and stretchability of the elastic stretchable member are lowered.
Then, the main subject of this invention is providing the expansion-contraction part formation method and its installation which fix an elastic expansion-contraction member and a sheet | seat, without using an adhesive agent.

The present invention that has solved the above problems is as follows.
<Invention of Claim 1>
Invention of Claim 1 uses the continuous sheet which pinched | interposed the several elastic elastic member arranged in parallel between the inner sheet | seat and the outer sheet | seat,
A method for forming a stretchable part of an absorbent article, wherein the elastic stretchable member is fixed by intermittently welding the inner sheet and the outer sheet in the supply direction,
With the tensile force applied to the elastic elastic member, in the vicinity of both sides in the diameter direction of the elastic elastic member , the inner sheet and the outer sheet are intermittently welded in the supply direction ,
Thereafter, in the cross-sectional space closed by the welded portion between the inner sheet and the outer sheet, the tensile force is released to the elastic elastic member to enlarge the cross-sectional outer diameter of the elastic elastic member, and the elastic elastic member The elastic elastic member is fixed to the sheet by a frictional force between an outer surface and the sheet forming the closed space .
This is a method for forming the stretchable part.

<Invention of Claim 2>
Invention of Claim 2 uses the continuous sheet which pinched | interposed the some elastic elastic member arranged in parallel between the inner sheet | seat and the outer sheet | seat,
A method for forming a stretchable part of an absorbent article, wherein the elastic stretchable member is fixed by intermittently welding the inner sheet and the outer sheet in the supply direction,
In a state where a tensile force is applied to the elastic elastic member , the inner sheet and the outer sheet are intermittently provided in the supply direction in the vicinity of both sides in the diameter direction of the elastic elastic member and on both sides overlapping the elastic elastic member. Welded,
Thereafter, in the cross-sectional space closed by the welded portion between the inner sheet and the outer sheet, the tensile force is released to the elastic elastic member to enlarge the cross-sectional outer diameter of the elastic elastic member, and the elastic elastic member The elastic elastic member is fixed to the sheet by the frictional force between the outer surface and the sheet forming the closed space, and the bonding force between the sheet at the side part ,
This is a method for forming the stretchable part.

(Function and effect)
The inner and outer sheets are intermittently welded in the vicinity of both sides in the diameter direction of the elastic elastic member in a state where a tensile force is applied to the elastic elastic member (extension state), and the elastic elastic member is fixed to the sheet. in, the subsequent elimination of the load (no tension), outer cross-sectional diameter of the resilient and elastic members is increased, the welding portion between the inner sheet and the outer sheet, relatively to sandwich the radial direction of the resilient and elastic members from both sides A pressing force is applied to the. As a result, since the elastic elastic member is fixed only by the frictional force with the sheet without fixing the elastic elastic member with the adhesive, deterioration due to the adhesive can be prevented. Moreover, since the elastic elastic member is not bonded, an expansion / contraction part in which air permeability and softness are ensured can be formed. The welding can be ultrasonic welding or heat welding. However, it is more preferable to use ultrasonic welding because the influence of heat and pressure on the elastic elastic member and the peripheral portion of the sheet is less than that of ultrasonic welding.
Further, in a state in which a tensile force is applied to the elastic elastic member, both sides in the diameter direction of the elastic elastic member, the inner sheet and the outer sheet are intermittently welded, and the elastic elastic member is fixed, In addition to the frictional force, the elastic elastic member is more firmly fixed by the welding force of the end portion in the diameter direction of the elastic elastic member. In addition, since joining is only the edge part of the elastic elastic member in the diameter direction , there is no possibility of deterioration or cutting of the elastic elastic member.

<Invention of Claim 3>
Invention of Claim 3 uses the continuous sheet which pinched | interposed the several elastic elastic member arranged in parallel between the inner sheet | seat and the outer sheet | seat,
An apparatus for forming a stretchable part of an absorbent article, wherein the elastic stretchable member is fixed by intermittently welding the inner sheet and the outer sheet with respect to a supply direction in a state where a tensile force is applied to the elastic stretchable member. There,
The apparatus includes an ultrasonic vibration source, a horn connected to the ultrasonic vibration source, and an anvil roll disposed to face the horn.
On the outer peripheral surface of the anvil roll, there are formed a plurality of protrusions that become adhesive surfaces,
These protrusions are arranged in a lattice pattern , and the interval between the protrusions in the width direction of the anvil roll is configured to be substantially the same as the outer diameter of the cross section of the elastic stretchable member in a state where a tensile force is applied. The elastic member is configured to pass through the interval and constitute a closed sectional space that wraps the elastic elastic member by a welded portion between the inner sheet and the outer sheet.
It is an expansion-contraction part formation apparatus characterized by the above-mentioned.

<Invention of Claim 4>
Invention of Claim 4 uses the continuous sheet which pinched | interposed the several elastic elastic member arranged in parallel between the inner sheet | seat and the outer sheet | seat,
An apparatus for forming a stretchable part of an absorbent article, wherein the elastic stretchable member is fixed by intermittently welding the inner sheet and the outer sheet with respect to a supply direction in a state where a tensile force is applied to the elastic stretchable member. There,
The apparatus includes an ultrasonic vibration source, a horn connected to the ultrasonic vibration source, and an anvil roll disposed to face the horn.
On the outer peripheral surface of the anvil roll, there are formed a plurality of protrusions that become adhesive surfaces,
These protrusions are staggered across the outer circumferential line , and the cross section of the elastic elastic member in the state where the protrusions adjacent to each other in the oblique direction with respect to the rotation direction of the anvil roll are applied with a tensile force. The elastic stretchable member is configured to have substantially the same length as the outer diameter, and the elastic stretchable member is configured to pass through the gap and form a closed cross-sectional space that wraps the elastic stretchable member by a welded portion between the inner sheet and the outer sheet. Being
It is an expansion-contraction part formation apparatus characterized by the above-mentioned.

(Function and effect)
On the outer peripheral surface of the anvil roll, there are formed a plurality of protrusions that become adhesive surfaces, and these protrusions are in a lattice shape, and the elastic protrusions in the state where the protrusions in the diametrical direction of the anvil roll are subjected to a tensile force. By configuring the length approximately the same as the cross-sectional outer diameter of the member, the inner and outer sheets of the continuous sheet are narrow in a state where the entire elastic stretchable member or the main part is stored in the groove between the protrusions of the anvil roll. It is pressed and ultrasonically welded by the projection and horn. As a result, when the entire elastic expansion / contraction member is in the groove, the elastic expansion / contraction member is fixed only by the frictional force with the sheet without using an adhesive, and the elastic expansion / contraction member In the case where the main part of the elastic member is housed in the groove and both sides in the diametrical direction are constricted by the horn and the protrusion, in addition to the frictional force with the sheet, the joining force at the diametrical end of the elastic elastic member An elastic elastic member comes to be fixed.
On the outer peripheral surface of the anvil roll, a plurality of protrusions that are adhesive surfaces are formed.The protrusions are staggered, and the diametric spacing between the protrusions adjacent to each other in an oblique direction with respect to the rotation direction of the anvil roll is set. The same effect as described above can be obtained even if the elastic stretchable member in a state where a tensile force is applied has the same length as the cross-sectional outer diameter.

  According to the present invention, the elastic part and the sheet can be fixed without using an adhesive in the elastic part.

Embodiments of the present invention will be described below.
As shown in FIG. 3, the stretchable part forming apparatus according to the present invention includes an ultrasonic vibration source 20, a horn 21 that is connected to the ultrasonic vibration source 20 and increases the vibration amplitude from the ultrasonic vibration source 20, An anvil roll 22 disposed opposite to the horn 21. The ultrasonic vibration source 20 is fixed to a pressure arm (not shown), and the height can be adjusted. Further, before and after the anvil roll 22, guide rolls for preventing loosening of the continuous sheet 10 in a state where the elastic elastic members 2, 2,.
Although not shown, the tension of the continuous sheet 10 is kept constant on the outer side of the guide roll in order to prevent the continuous sheet 10 in a state where the elastic elastic members 2, 2,. In order to maintain, it is more preferable to use tension control such as a step roll.

  The continuous sheet 10 is formed by laminating and fixing two or three or more breathable / water-repellent nonwoven fabrics, and a plurality of elastic sheets arranged in parallel between the inner sheet 1A and the outer sheet 1B. The elastic members 2, 2,. As the nonwoven fabric, a polypropylene resin (PP), a polyethylene resin (PE), a polyethylene terephthalate resin (PET), a composite of these, or the like can be used. Furthermore, the continuous sheet 10 is not limited to a nonwoven fabric, and a film made of a polyethylene resin or the like can be used as long as it can be fixed by heat welding or ultrasonic welding, and a nonwoven fabric and a film can be used in combination.

  Moreover, the elastic elastic member 2 can use a well-known elastic yarn, if it has an elastic property and can be fixed in tension with the surrounding nonwoven fabric. Materials include natural rubber, polyurethane, block polyether amide, block polyether ester, polyurethane urea, elastic polyolefin, thermoplastic styrene-butadiene-styrene (SBS), styrene-isoprene-styrene, styrene-ethylene / propylene-styrene, Styrene-ethylene-butadiene-styrene (SEBS), hydrogenated styrene-butadiene-rubber and elastomers based on these and other polymers such as polystyrene or polyolefins can be used. Also, elastic yarns from segmented polyester or polyether urethane-urea can be used.

The thickness of the elastic elastic member 2 can be arbitrarily set. Further, the cross-sectional shape is not limited to a circle, but can be freely selected from an ellipse, a rectangle, and other geometric shapes.
Furthermore, the elastic elastic member 2 is not limited to a thread-like one, and although not shown, a wide ribbon-like or net-shaped one can also be employed. In the case of a ribbon, it is preferable that both sides in the diameter direction are welded to the sheet together with the inner and outer sheets. In the case of the net shape, it is preferable to weld the inner and outer sheets not only on the elastic yarn in the tensile direction but also on the elastic yarn orthogonal to the tensile yarn in the vicinity of both sides in the diameter direction . In this case, the orthogonal elastic yarn and the welded portion may be separated from each other, but if the welded portion is welded not only to both sides in the diameter direction of the elastic yarn but also to the central portion, the elastic yarn breaks or the welded portion becomes hard. Since there is a possibility, it is not preferable.

  As shown in FIGS. 4 (1) and (2), the anvil roll 22 has a plurality of projections 22A, 22A,... That serve as ultrasonic welding surfaces. A groove having a predetermined depth is formed between 22A,. The horn 21 and the protrusion 22A of the anvil roll 22 pinch the continuous sheet 10, and the inner sheet 1A and the outer sheet 1B of the continuous sheet 10 are welded by the welding portion 3 as shown in FIGS. 5 (1) and (2). However, the groove portion formed between the protrusions 22A and 22A is not fused, and a gap is formed in the folded continuous sheet 10. In the figure, the inner sheet 1A is located at the upper part and the outer sheet 1B is located at the lower part. However, the inner sheet 1A may be located at the lower part and the outer sheet 1B may be located at the upper part. The same applies to this point.

As shown in FIGS. 4 (1) and (2), the space between the axial projection 22A and the projection 22A of the anvil roll 22 is the cross-sectional outer diameter of the elastic elastic member 2 in a state where a tensile force is applied in the longitudinal direction ( It is preferable that the length is substantially the same as the width. In a paper diaper, it is common to fix a polyurethane thread rubber having a thickness of about 400 to 1000 decitex as an elastic stretch member to a sheet in a stretched state 2 to 3 times. The outer diameter of the elastic elastic member 2 is about 0.18 to 0.22 mm, and the interval between the protrusions 22A, 22A,. More preferably, it is preferably 0.9 to 1 times (excluding 1) the outer diameter of the cross section of the elastic elastic member 2 in a state pulled in the longitudinal direction.

As shown in FIGS. 4 (1) and (2), the grooves between the protrusions 22A, 22A,... Are for accommodating the elastic elastic member 2 so that the elastic elastic member 2 is not narrowed by the protrusions. Therefore, the space | interval of an adjacent groove | channel corresponds with the arrangement | positioning space | interval of the elastic elastic members 2, 2, ... which adjoin in the continuous sheet 10. FIG. Further, the depth of the groove between the protrusions 22A, 22A,... May be deep enough to accommodate the elastic elastic member 2 and deep enough that the continuous sheet 10 does not sag too much.
As shown in FIGS. 4 (1) and (2), the protrusions 22A are arranged in a lattice pattern, and the space between the protrusions 22A and 22A in the axial direction of the anvil roll 22 is applied with a tensile force in the longitudinal direction. When the outer diameter of the elastic elastic member 2 is 1 to 1.1 times the outer diameter of the elastic elastic member 2, the elastic elastic member 2 is grooved when guided between the horn 21 and the anvil roll 22 in which the protrusions 22A are arranged in a lattice shape. The inner sheet 1 </ b> A and the outer sheet 1 </ b> B of the continuous sheet 10 are narrowed and are ultrasonically welded by the protrusion 22 </ b> A and the horn 21. As a matter of course, since the elastic elastic member 2 is received in the groove, the elastic elastic member 2 under tension is not narrowed by the protrusion 22 and the horn 21.

As shown in FIGS. 5 (1) and (2), this welding is performed in a state where tension is applied to the elastic elastic member 2 and in the vicinity of both sides in the diametrical direction of the elastic elastic member 2. When the load is removed (no tension), as shown in FIGS. 6 (1) and (2), the cross-sectional outer diameter of the elastic stretchable member 2 is increased, and the welded portion 3 between the inner sheet 1A and the outer sheet 1B is elastic. A pressing force is applied so as to sandwich the diameter direction of the elastic member 2 from both sides. As a result, the elastic elastic member 2 is fixed only by the frictional force with the inner and outer sheets 1A and 1B without using an adhesive.
Thereby, deterioration by the adhesive of the elastic elastic member 2 can be prevented. Moreover, since the elastic elastic member 2 is not bonded, the shearing S in which air permeability and softness are ensured can be formed. In addition, since the material itself is melted and welded , the fluctuation cost of hot melt can be reduced, and machine troubles caused by hot melt can be prevented.
Furthermore, it goes without saying that the present invention can be applied to barrier cuffs, gasket cuffs and the like composed of an elastic elastic member and a sheet, and the elastic elastic member can be fixed to the sheet.

Further, as shown in FIGS. 7A and 7B, the protrusions 22B of the anvil roll 22 are arranged in a lattice shape, and the distance between the protrusions 22B and 22B in the axial direction of the anvil roll 22 is set in the longitudinal direction. In the case of 0.9 to 1 times (excluding 1) the cross-sectional outer diameter of the elastic elastic member 2 in a state where a tensile force is applied, both diametrical side portions of the elastic elastic member 2 have horns 21 and protrusions. The pressure is narrowed by 22B, and ultrasonic welding is performed by the welding portion 3 together with the inner sheet 1A and the outer sheet 1B, as shown in FIGS. In this case, as shown in FIGS. 9 (1) and 9 (2), when the load is eliminated (no tension), in addition to the frictional force with the inner and outer sheets 1A and 1B, both sides of the elastic elastic member 2 in the diametrical direction The elastic elastic member 2 is fixed by the welding force. Here, since the welding is performed only at the end portion of the elastic elastic member 2, there is almost no risk of deterioration or cutting of the elastic elastic member 2 in a normal case.

The arrangement of the protrusions is not limited to the lattice shape, and may be a staggered array of protrusions 22C as shown in FIG. At this time, the protrusion 22C and the distance in the diameter direction and the projection 22C, outer cross-sectional diameter of the resilient and elastic members 2 in a state where a load of tensile force in the longitudinal direction adjacent in an oblique direction with respect to the rotational direction of the anvil roll 22 1 to 1.1 times, the elastic elastic member 2 is fixed only by the frictional force between the inner and outer sheets 1A and 1B without using an adhesive. In addition, when the elastic elastic member 2 is applied with a tensile force in the longitudinal direction and has an outer diameter of 0.9 to 1 (excluding 1), the frictional force between the inner and outer sheets 1A and 1B. In addition to this, the elastic elastic member 2 is fixed by the welding force of the both sides in the diameter direction of the elastic elastic member 2.

In addition, if the space | interval (groove width) of the diameter direction of protrusion 22A-22C and protrusion 22A-22C is in the said range with respect to the cross-section outer diameter of the elastic expansion-contraction member in the state which applied the tensile force, The arrangement pattern of the protrusions 22A to 22C is not limited to a lattice shape or a zigzag shape, and may be another pattern.
In addition, when the elastic elastic member 2 is welded and fixed with the groove width being 0.9 to 1 times the outer diameter of the elastic elastic member 2 in an expanded state (not including 1), the holding force of the elastic elastic member 2 is very high. Therefore, it is preferable, however, when the elongation rate is high, the elastic elastic member 2 is easily cut, so care should be taken. In particular, when the elongation rate is 300% or more, it is not preferable to make the groove width 0.9 to 1 time (not including 1).

  Further, when the elastic elastic member 2 is fixed only by frictional force without welding, when the elastic elastic member 2 and the sheets 1A and 1B have high frictional resistance, or when the elastic elastic member 2 has a low elongation rate, the groove Although the width can be expanded to about 1.3 times the cross-sectional outer diameter of the elastic elastic member 2 in the stretched state, 1.0 to 1.2 times is preferable in a normal case, and 1.0 to 1.1 times is particularly preferable. preferable. In this case, the holding force (friction resistance) becomes higher as it becomes closer to 1 time, but there is a risk of the elastic elastic member 2 being cut. Needless to say, the groove width needs to be in the above range and narrower than the diameter of the elastic elastic member 2 at the time of relaxation. In order to ensure the holding force, the groove width is desirably 70% or less of the relaxed diameter of the elastic elastic member 2.

  It is desirable that the depth of the groove (the height of the protrusions 22A to 22C) is the same as the groove width. Specifically, the depth of the groove is preferably 0.9 to 1.2 times the outer cross-sectional dimension of the stretched elastic elastic member 2. The most preferable range is 1.0 to 1.1 times. If it is smaller than 1.0 times, the force for holding the elastic elastic member 2 becomes strong, but the entire elastic elastic member 2 may be welded. Further, it is not preferable that the depth of the groove is larger than the cross-sectional outer diameter of the elastic elastic member 2 when relaxed. When the sheets 1A and 1B have the property of being easily distorted in the CD direction (axial direction of the anvil roll) like a nonwoven fabric, if the groove is too deep, the sheets 1A and 1B are stretched and distorted during pinching, There is a possibility that the force for holding the elastic elastic member 2 cannot be obtained sufficiently.

  In addition, the shape of each of the protrusions 22A to 22C is circular in the illustrated example, but may be a polygonal shape such as a triangle or a quadrangle, or a pattern such as an ellipse, a star, or a heart. If a shape without corners such as a circle or an ellipse is used, a soft texture can be obtained. If a shape with a corner is used and the corner is disposed so as to face the elastic elastic member 2, the elastic elastic member 2 is retracted (the elastic elastic member 2 contracts while being displaced without being fixed by the sheets 1A and 1B). ) Can be prevented more reliably. In this case, the smaller the angle facing the elastic elastic member 2 is, the smaller the pull-in is. The angle of the angle facing the elastic elastic member 2 is preferably 15 to 120 degrees, and particularly preferably 30 to 90 degrees.

In the case of a circle, the size of the protrusions 22A to 22C is preferably 0.2 to 10 mm, more preferably 0.3 to 5 mm, and particularly preferably 0.3 to 1 mm. Most preferably, it is 0.3 to 0.6 mm. The smaller the diameter, the better the texture of the sheet. However, if it is too small, the bonding strength between the sheets 1A and 1B cannot be sufficiently obtained. Conversely, when the protrusions 22A to 22C are too large, the texture is lowered. For other shapes, the area in the case of a circle may be set as a reference, and the dimensional ratio between length and width may be extremely different. Area of the tip surface of the projection 22A~22C is preferably a 0.03~80mm ^2, more preferably from 0.07~20mm ^2, particularly preferably in the range of 0.07~0.8mm ^2, Most preferably, it is 0.07 to 0.3 mm ² .

  The spacing between the protrusions 22A to 22C in the MD direction (the circumferential direction of the anvil roll and the longitudinal direction of the elastic elastic member 2) can be generally about 0.3 to 20 mm, but is not particularly limited thereto. Alternatively, the protrusions 22A to 22C may be continuous in the MD direction in a strip shape (linear shape). In order to balance the texture of the sheets 1A and 1B, the adhesive strength between the sheets 1A and 1B, and the fixation of the elastic elastic member 2, for example, if the protrusions 22A to 22C have a circular shape with a diameter of 0.3 to 0.6 mm. The intervals between the protrusions 22A to 22C may be, for example, about 0.3 to 1.0 mm in the MD direction and about 0.3 to 1.5 mm in the CD direction (axial direction of the anvil roll). Note that the spacing in the MD direction and the spacing in the CD direction of the protrusions 4A to 4C are indicated by reference numerals DMD and DCD, respectively, in FIG.

When the arrangement of the protrusions 22A to 22C is the above-described lattice arrangement, the protrusions 22A to 22C are located on both sides in the diameter direction at the same portion in the longitudinal direction of the elastic elastic member 2, so that a high holding force is obtained. However, the risk that the elastic elastic member 2 is welded or cut increases. On the other hand, when the zigzag arrangement is used, the risk that the elastic elastic member 2 is welded or cut is reduced, but the holding force is also reduced. In the staggered arrangement, the rows of protrusions arranged in the MD direction at a predetermined periodic interval are provided with a predetermined interval in the CD direction, and the phase of the arrangement period of the protrusions in each row is shifted from the adjacent row. Yes, it may be arranged so that the phase is shifted by 1/2 with respect to the adjacent protrusion rows as shown in the example, but in order to make it closer to the lattice arrangement, for example, the phase is shifted by 1/4. May be. By adjusting the phase shift between 0 and 1/4, it is possible to balance the holding force of the elastic elastic member 2 and the avoidance of cutting.

  In order to obtain a soft texture, the area ratio of the welded portion 3 in the fixed region of the elastic elastic member 2 is preferably 40% or less, particularly preferably 30% or less, and 20% or less. Most preferably. Further, in the non-fixed region of the elastic elastic member 2, the area ratio of the welded portion 3 needs to be at least 2% in order to maintain the bonding strength of the sheets 1A and 1B. In the fixed region of the elastic elastic member 2, the sheet bends due to the contraction of the elastic elastic member 2, so that a bonding strength equal to or higher than the non-fixed region of the elastic elastic member 2 is required. Therefore, in the fixed region of the elastic elastic member 2, the area ratio of the welded portion 3 is preferably 5% or more, and more preferably 10% or more.

  The stretchable sheet forming method and its equipment according to the present invention are not limited to stretchable parts such as shirring and barrier cuffs and gasket cuffs in pant-type paper diapers, but also stretchable such as waist gathers, barrier cuffs, gasket cuffs and stretchable tapes of tape-type paper diapers. The present invention can also be applied to the formation of parts, and can also be applied to the formation of stretchable parts such as barrier cuffs and gasket cuffs in general absorbent articles including napkins and the like.

FIG. 11 shows a case where the present invention is applied to the elastic elastic member 2 used for shearing formation around the trunk of a pants-type paper diaper. In the illustrated form, the elastic elastic member 2 on the back side and / or the elastic elastic member 2 on the abdominal side is cut or provided at the central portion in the diametrical direction (the portion overlapping the portion having the absorber that absorbs and holds excrement). However, it may be continuous from one end in the diameter direction to the other end. In the case where the elastic stretchable member 2 is provided over a wide range as in the case of the waistline portion, the portion fixed by the welded portion 3 is intermittently provided in the longitudinal direction (MD direction) of the elastic stretchable member 2 (that is, at the above-described arrangement / interval). The welded portion group region 44 formed of a large number of welded portions 3 and the non-welded portion region 45 having no welded portion are alternately formed in the longitudinal direction (MD direction) of the elastic stretchable member 2) and stretchable As a result, the area of the welded portion 3 is reduced and a softer texture and higher air permeability can be obtained. Of course, as shown in FIG. 12, the welding part group area | region 44 fixed by the welding part 3 can also be provided continuously over the whole longitudinal direction (MD direction) of the elastic expansion-contraction member 2. As shown in FIG.

  The intermittent arrangement of the welded portion group region 44 can be applied to a case where a large number of elastic elastic members 2 are arranged side by side. The wrinkles formed by the contraction of the member 2 become irregular, and an uneven surface with poor appearance is formed. Therefore, when adopting the intermittent arrangement as described above, as shown in FIG. 11, it is preferable to align the position of the fixing portion by the welded portion in the longitudinal direction (MD direction) of the elastic elastic member 2. Specifically, an elongated welded portion group region 44 that vertically cuts the elastic elastic members 2 arranged side by side and a non-welded portion region 45 that cuts the elastic elastic members 2 arranged side by side are arranged in the longitudinal direction of the elastic elastic member 2. They are formed alternately in the direction (MD direction). As a result, a beautiful shirring of the kites is formed. The width (the distance between the centers of the welded portions 3 located at both ends) W44 of the welded portion group region 44 is preferably about 2 to 10 mm, and more preferably about 3 to 5 mm. It is preferable that the center interval DCT between adjacent welded portion group regions 44 is about 5 to 20 mm. Furthermore, it is more preferable that the relationship of DCT / 2 ≧ W44 is satisfied.

  Further, when the elastic expansion / contraction member 2 has a high expansion ratio and a large tensile force is applied to the expansion / contraction portion during use, the elastic expansion / contraction member 2 is sufficiently fixed only by the frictional force with the inner and outer sheets 1A and 1B. There is a possibility that it cannot be done. In that case, at least one end of the elastic expansion / contraction member 2 in the longitudinal direction is connected to the elastic expansion / contraction member 2 by a substantially linear welding line arranged to cut the elastic expansion / contraction member 2 arranged in parallel. The inner and outer sheets 1 </ b> A and 1 </ b> B of the exterior sheet 12 may be welded and fixed to secure the elastic elastic member 2.

  On the other hand, as can be seen from the above embodiment, the ultrasonic bonding method is suitable for carrying out the stretchable part forming method of the present invention, but it is composed of an embossed roll provided with unevenness and a plain roll facing the heat, and heat and It can also be carried out using a hot embossing adhesion method in which a sheet is pressure-bonded by pressure.

<Evaluation test>
By the manufacturing method according to the present invention using ultrasonic welding, various stretchable sheets are manufactured under the conditions shown in Table 1, and “softness”, “sheet interlayer adhesion”, “difficult to pull out (retraction is difficult to occur) ”And“ difficult to cut ”were evaluated.
In addition, as an inner sheet and an outer sheet, a spunbond nonwoven fabric (one layer, basis weight: 20 g / m ² , thickness: 0.18 mm, fineness 2.2 dtex, composition: PE (sheath) / PP (core) = 1 / 1, sheet width: 150 mm). Further, as the elastic stretchable member 2, a spandex of 470 dtex (diameter: 0.311 mm) is used, and is stretched to 270% along the lateral direction of the sheet (2.7 times the original length, the diameter is 0.162 mm). Fixed in the state. Further, 20 elastic stretch members 2 were arranged in parallel at intervals of 5 mm.
“Softness” is a sensory evaluation in comparison with a sheet in which an elastic elastic member is fixed with a conventional adhesive, and 9 to 10 test subjects are evaluated as soft. Was evaluated as ◯, 4 to 6 were evaluated as soft, △ was evaluated as 3 or less were evaluated as ×. In the evaluation of “sheet interlayer adhesion”, “◎” indicates that the sheet itself was destroyed when the adhered sheet was peeled off by hand, and “◯” indicates that the sheet was partially broken or accompanied by delamination. In addition, a sample which was peeled off while leaving a slight fluff was represented by Δ, and a sample which did not substantially adhere was represented by ×. “In the evaluation of the difficulty of pulling out (the difficulty of pulling in), when the sheet is cut, the elastic elastic member from the cut part is 1 mm or less, ◎◎, 3 mm or less is ◎, 5 mm The following were marked with ◯, those with 10 mm or less as Δ, and those with 11 mm or more as x: In the evaluation of “difficult to cut”, there was one cut in the range of 100 mm in the length direction of the sheet. The following were evaluated as ◎, those at 5 or less locations as ◯, those at 10 locations or less as Δ, those at 20 locations or less as Δ to ×, and those at 21 locations or more as ×.

It is a perspective view of a pants-type paper diaper. It is an enlarged view of a shearing part. It is a schematic diagram for demonstrating an expansion-contraction part formation apparatus. It is a diameter direction sectional view of the 1st embodiment which shows the state where a continuous sheet was pinched between a horn and an anvil roll, and its transverse cross section. It is a diameter direction sectional view of the 1st embodiment of a continuous sheet in the state where tension was applied to an elastic elastic member, and its transverse sectional view. It is a diameter direction sectional view of a 1st embodiment of a continuous sheet in the state where tension is not applied to an elastic elastic member, and its cross section. It is the diameter direction sectional view of 2nd Embodiment which shows the state where the continuous sheet was pinched | interposed into the horn and the anvil roll, and its cross section. It is a diameter direction sectional view and a transverse sectional view of a 2nd embodiment of a continuous sheet in the state where tension was applied to an elastic elastic member. It is a diameter direction sectional view of the 2nd embodiment of the state of a state where tension is not applied to an elastic elastic member, and its transverse section. It is a cross-sectional view showing a state in which a continuous sheet is sandwiched between anvil rolls having an array of staggered protrusions. It is the schematic which shows the example of application to the trunk part part shirring of a pants-type paper diaper. It is the schematic which shows the other application example to the trunk periphery part shearing of a pants-type paper diaper.

  DESCRIPTION OF SYMBOLS 1 ... Sheet | seat, 2 ... Elastic expansion-contraction member, 3 ... Welding part, 10 ... Continuous sheet, 20 ... Ultrasonic vibration source, 21 ... Horn, 22 ... Anvil roll, 22A, 22B, 22C protrusion, S ... Shirring.

Claims (4)

Using a continuous sheet with a plurality of elastic elastic members arranged in parallel between the inner sheet and the outer sheet,
A method for forming a stretchable part of an absorbent article, wherein the elastic stretchable member is fixed by intermittently welding the inner sheet and the outer sheet in the supply direction,
With the tensile force applied to the elastic elastic member, in the vicinity of both sides in the diameter direction of the elastic elastic member , the inner sheet and the outer sheet are intermittently welded in the supply direction ,
Thereafter, in the cross-sectional space closed by the welded portion between the inner sheet and the outer sheet, the tensile force is released to the elastic elastic member to enlarge the cross-sectional outer diameter of the elastic elastic member, and the elastic elastic member The elastic elastic member is fixed to the sheet by a frictional force between an outer surface and the sheet forming the closed space .
A stretchable part forming method characterized by the above. Using a continuous sheet with a plurality of elastic elastic members arranged in parallel between the inner sheet and the outer sheet,
A method for forming a stretchable part of an absorbent article, wherein the elastic stretchable member is fixed by intermittently welding the inner sheet and the outer sheet in the supply direction,
In a state where a tensile force is applied to the elastic elastic member , the inner sheet and the outer sheet are intermittently provided in the supply direction in the vicinity of both sides in the diameter direction of the elastic elastic member and on both sides overlapping the elastic elastic member. Welded,
Thereafter, in the cross-sectional space closed by the welded portion between the inner sheet and the outer sheet, the tensile force is released to the elastic elastic member to enlarge the cross-sectional outer diameter of the elastic elastic member, and the elastic elastic member The elastic elastic member is fixed to the sheet by the frictional force between the outer surface and the sheet forming the closed space, and the bonding force between the sheet at the side part ,
A stretchable part forming method characterized by the above. Using a continuous sheet with a plurality of elastic elastic members arranged in parallel between the inner sheet and the outer sheet,
An apparatus for forming a stretchable part of an absorbent article, wherein the elastic stretchable member is fixed by intermittently welding the inner sheet and the outer sheet with respect to a supply direction in a state where a tensile force is applied to the elastic stretchable member. There,
The apparatus includes an ultrasonic vibration source, a horn connected to the ultrasonic vibration source, and an anvil roll disposed to face the horn.
On the outer peripheral surface of the anvil roll, there are formed a plurality of protrusions that become adhesive surfaces,
These protrusions are arranged in a lattice pattern , and the interval between the protrusions in the width direction of the anvil roll is configured to be substantially the same as the outer diameter of the cross section of the elastic stretchable member in a state where a tensile force is applied. The elastic member is configured to pass through the interval and constitute a closed sectional space that wraps the elastic elastic member by a welded portion between the inner sheet and the outer sheet.
A stretchable part forming apparatus. Using a continuous sheet with a plurality of elastic elastic members arranged in parallel between the inner sheet and the outer sheet,
An apparatus for forming a stretchable part of an absorbent article, wherein the elastic stretchable member is fixed by intermittently welding the inner sheet and the outer sheet with respect to a supply direction in a state where a tensile force is applied to the elastic stretchable member. There,
The apparatus includes an ultrasonic vibration source, a horn connected to the ultrasonic vibration source, and an anvil roll disposed to face the horn.
On the outer peripheral surface of the anvil roll, there are formed a plurality of protrusions that become adhesive surfaces,
These protrusions are staggered across the outer circumferential line , and the cross section of the elastic elastic member in the state where the protrusions adjacent to each other in the oblique direction with respect to the rotation direction of the anvil roll are applied with a tensile force. The elastic stretchable member is configured to have substantially the same length as the outer diameter, and the elastic stretchable member is configured to pass through the gap and form a closed cross-sectional space that wraps the elastic stretchable member by a welded portion between the inner sheet and the outer sheet. Being
A stretchable part forming apparatus.

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