The prevent invention relates to production of a stretchable laminate for a wearable article.
In the following prior art, the stretchable laminate is formed by disposing a plurality of elastic members between two sheets and jointing the two sheets to each other intermittently in both directions of the stretching direction of the elastic members and the direction crossing the stretching direction.
First patent document: JP2005-212405A (front page)
Both sheets are jointed by passing between an anvil roll having projections and a sonic horn or the like (heating/pressurizing means) facing the anvil roll. To reduce a pressure at the time of jointing, the elastic members are housed in carrying grooves provided on the projections.
The above-described projection for jointing is formed to have a height of 100 μm or larger, for example, so as to house the stretched elastic member in the carrying groove.
However, the sheets wound on the anvil roll tend to shrink in the radial direction of the anvil roll due to carrying tension, and may unexpectedly displace in the axial direction of the anvil roil. If the displacement of the sheets causes displacement of the elastic member as well, the elastic member may be removed from the carrying groove and ruptured by pressing force at the time of jointing.
The present invention aims at providing a method and device for producing a stretchable laminate for a wearable article while suppressing removal of the elastic member from the carrying groove and rupture of the elastic member, when the both sheets are jointed to each other on the anvil roll with projections provided intermittently in the axis direction.
The present invention includes an anvil roll 50 that carries a pair of first and second sheets 1, 2 and elastic members F so that the elastic members F are sandwiched between the pair of first and second sheets 1, 2, and
a fusion device 70 that, in cooperation with the anvil roll 50, fuses the pair of first and second sheets 1, 2 mutually and makes the pair of first and second sheets 1, 2 hold the elastic members F, wherein
an outer peripheral surface 51 of the anvil roll 50 includes a plurality of first projections 52H for producing first joint portions 31 where the pair of first and second sheets 1 s jointed to each other, the first projections being provided along a width direction S of the anvil roll 50 and spaced from each other in the width direction S,
each of the first projections 52H defines and includes a carrying groove G extending in a circumferential direction R of the anvil roll 50 and carrying each of the elastic members while each of the elastic members F has entered (been housed) in the groove G, and
at least one receiving part 52L for receiving the pair of first and second sheets 1, 2 is arranged (disposed) between one first projection 52H and another first projection 52H adjacent to each other in the width direction S, among the plurality of first projections 52H each including the carrying groove G.
In a method for producing a stretchable laminate according to the present invention, the stretchable laminate 10 including the elastic members F spaced from each other and sandwiched by the pair of first and second sheets 1, 2, the pair of first and second sheets 1, 2 being jointed to each other at each of the first joint portions 31, the first joint portions arranged in columns in a stretching direction Df of the elastic members F and arranged in rows in a direction Dp crossing the stretching direction Df,
the method includes the following steps. That is, the present method includes:
a step of introducing the first sheet 1 of the pair of first and second sheets onto the anvil roll 50;
a step of introducing the elastic members F onto the first sheet 1 on the anvil roll 50 and introducing the elastic members F so that each of the elastic members F enters (are housed) in each of the carrying grooves G of the anvil roll 50;
a step of carrying the first sheet 1 and the elastic members F while receiving the first sheet 1 at the at least; one receiving part 52L between the one first projection 52H and the another first projection 52H, each including the respective carrying grooves G, so as to suppress shrinkage of the first sheet 1 in a radial direction of the anvil roll 50;
a step of introducing, on the anvil roll 50, the second sheet 2 of the pair of first and second sheets, onto the first sheet 1 so as to sandwich the elastic members F between the first sheet 1 and the second sheet 2; and
a step of forming the first joint portions 31 by fusing the first sheet 1 and the second sheet 2 on the one and the another first projections 52H of the anvil roll 50 without fusing the first sheet 1 and the second sheet 2 at the receiving part 52L.
In the present invention, the carrying groove G included in the first projection 52H is provided so that at least one carrying groove G for one first projection 52H divides a projection surface of the one first projection 52H in the width direction S. That is, each of the carrying grooves G is a V-shaped or U-shaped notch, for example, and is defined by a surface of the notch formed in the first projection 52H in the center in the width direction S of the first projection 52H.
The depth of the carrying groove G may be a depth with which the pair of sheets 1, 2 and the elastic member F therebetween are fused mutually or a depth with which they are not fused mutually. In the case where the pair of sheets 1, 2 and the elastic member F are fused mutually in the carrying groove G, a bottom surface of the carrying groove G is defined by the first projection 52H. That is, in such a case, the carrying groove G is surrounded by the first projections 52H on both sides in the width direction S and the lower side.
Note that a plurality of carrying grooves G may be provided for one first projection 52H.
In the present invention, a pair of sheets are jointed to each other by a fusing structure at least at; a pair of joint portions on both sides in the width direction (the crossing direction) of each of the elastic members. That is, the pair of sheets are jointed to each other by the fusing structure at least at a pair of first projections 52H on both sides of each carrying groove G, so as to generate a stretchable laminate in which the elastic member F is sandwiched between the pair of sheets.
On the anvil roll, the sheet is received by the receiving part between the projections for jointing. As such, this suppresses displacement of the sheets and the elastic members F in the axis direction (width direction) of the anvil roll. As a result, this is expected to suppress the removal of the elastic members from the carrying grooves and the rupture of the elastic members at the time of jointing.
In the preferred device, the receiving part comprises at least two receiving parts 52L provided between the one first projection 52H and the another first projection 52H, and
a second projection 52S for producing a second joint portion 32 where the pair of first and second sheets 1, 2 is jointed to each other is provided between the at least two receiving parts 52L.
The height of the receiving part 52L is preferably smaller by 51 to 300 μm than the height of the first projection 52H.
If the height of the receiving part 52L is excessively smaller than that of the first; projection 52H, the first sheet tends to shrink in the radial direction of the anvil roll 50 together with the elastic member F before the first sheet is received by the receiving part 52L, thus causing the elastic member F to easily displace in the axis direction of the anvil roll 50.
On the other hand, if the height of the receiving part 52L is close to the same degree of the first projection 52H, the pair of sheets easily fuse mutually to be disadvantageously jointed to each other at the receiving part 52L, depending on the thickness and the kind of the sheets.
From such a viewpoint, the height of the receiving part 52L is preferably smaller by 60 to 300 μm than that of the first projection 52H, more preferably smaller by 70 to 300 μm, still more preferably smaller by 70 to 250 μm, and most preferably smaller by 70 to 200 μm.
However, depending on the kind and thickness of the sheets, a difference of the height may he around 20 to 300 μm.
Any feature illustrated and/or depicted in conjunction with one of the aforementioned aspects or the following embodiments may be used in the same or similar form in one or more of the other aspects or other embodiments, and/or may be used in combination with, or in place of, any feature of the other aspects or embodiments.
The present invention will be understood more clearly from the following description of preferred embodiments taken in conjunction with the accompanying drawings. Note however that the embodiments and the drawings are merely illustrative and should not be taken to define the scope of the present invention. The scope of the present invention shall be defined only by the appended claims. In the accompanying drawings, like reference numerals denote like components throughout the plurality of figures.
Prior to the description of an example of the stretchable laminate, there is described an example of a structure of a disposable wearable article in which the stretchable laminate is used.
In
The wearable article 90 is worn in the state where the crotch part 92a is folded in half along a virtual line parallel to the around-torso direction X. In this manner, ends in the around-torso direction X of the around-torso members 91, 91 overlap each other.
Each of the front and rear around-torso members 91 includes the stretchable laminate 10 illustrated clearly in
The first sheet 1 and the second sheet 2 are formed of a breathable nonwoven fabric. The elastic member F is sandwiched between the first sheet 1 and the second sheet 2, and is stretchable in the around-torso direction X.
The stretchable laminate 10 of the wearable article 90 (
The following will describe an example of the stretchable laminate 10.
First, the elastic member F in the stretched state will be described.
As illustrated in
As illustrated in
Each of the joint portions 3 is formed by the pair of sheets 1, 2 fused mutually on the first; surfaces 1f, 2f of the pair of sheets 1, 2 in
In
The elastic member F may be linear or of rope form. For example, as illustrated in
In the state where the elastic members F are shrunk, the stretchable laminate 10 forms a number of pleats P by a shrinkage force of the elastic members F, as illustrated in
The sheets 1, 2 may be thermoplastic nonwoven fabrics in which a number of thermoplastic fibers are laminated. The pleats P of
The second joint portion 32 is disposed between adjacent elastic members F of the elastic members F and between a pair of first joint portions 31 and another pair of first joint portions 31 adjacent to the pair in the crossing direction Dp. In the present example, one second joint portion 32 is provided between a pair of joint portions 31 and another pair of first joint portions 31.
The jointing force of the pair of sheets 1, 2 at the second joint portion 32 may be smaller or larger than the jointing force of the pair of sheets 1, 2 at the first joint portion 31.
In
At the fixing parts 3f of
In the case where the elastic members F are fixed between the pair of sheets 1, 2 of
In
The following will describe an example of the production device of the stretchable laminate 10.
The production device of
The introducing device 60 guides and introduces the elastic member F to the anvil roll 50. Moreover, the first sheet 1 is introduced to the anvil roll 50 at a point further upstream than the elastic member F, and the second sheet 2 is introduced to the anvil roll 50 at a point further downstream than the elastic member F. The anvil roll 50 carries the pair of sheets 1, 2 and the elastic member F so that the elastic member F is disposed between the pair of sheets 1, 2.
In cooperation with the anvil roll 50, the fusion device 70 fuses the pair of sheets 1, 2 mutually and fuses the sheets 1, 2 to the elastic member F so that the sheets 1, 2 hold the elastic member F. In the case of the present example, the fusion device 70 is an ultrasonic fusion device performing the fusion bonding by ultrasonic energy.
The fusion device 70 provides vibrational energy at a plurality of joint portions 3 (
To be more specific, the anvil roll 50 of
In
In this manner, with the ridges 52 and the recessed grooves 59, the first projections 52H are provided in a matrix form in the circumferential direction R and the width direction S of the roll 50, and the carrying grooves G are provided in a matrix form in the circumferential direction R and the width direction S of the roll 50.
The fusion device 70 of
In
As illustrated in
As illustrated in
Note that although
The introducing device 60 of
The first and second rolls 61, 62 may be free rollers, and may be driven to rotate in synchronization with the anvil roll 50. Moreover, the first and second rolls may not be provided.
As illustrated clearly in
In
The height H1 of the receiving part 52L of
In
The carrying groove G is defined by (a pair of) regions on both sides in the width direction S of the first projection 52H and the region of the first projection 52H on the lower side of the carrying groove G. That is, the regions on the both sides of the first projection 52H and the region on the lower side of the same first projection 52H define the bottom surface of the carrying groove G. For example, as illustrated in
As illustrated in
In the case of this example, two receiving parts 52L are provided between the pair of first projections 52H and the another pair of first projections 52H. Between the two receiving parts 52L, there is provided the second projection 52S for generating the second joint portion 32 (
The following will describe an example of the method for producing the stretchable laminate 10 using the production device.
As illustrated in
To suppress shrinkage of the first sheet 1 in the radial direction of the anvil roll 50, the first sheet 1 and the elastic member F are carried while the first sheet 1 is received at the receiving parts 52L between a pair of first projections 52H and another pair of first projections 52H as illustrated by two-dot chain lines in
Meanwhile, the second sheet 2 of
When the first sheet 1, the elastic members F, and the second sheet 2 pass between the horn 71 and the ridges 52, the horn 71 is ultrasonically vibrated in the direction toward the anvil roll 50. In this manner, the sheets 1, 2 are fused mutually at the first joint portions 31 and the second joint portions 32 of
Here, the first sheet 1 and the second sheet 2 are not fused at the receiving parts 52L of
As enlarged and illustrated in
At each of the projections 52H, 52S of
Meanwhile, in
Moreover, as exemplified by two-dot chain lines of
As illustrated in
As illustrated in
As in the examples of
Incidentally, the receiving part 52L may have the same height as the outer peripheral surface of the anvil roll 50. Moreover, although the effect; of preventing displacement of the elastic member is not expected in such a case, the receiving parts 52L may be formed at intermittent portions in the circumferential direction of the projections for jointing.
As described above, the preferred examples have been described with reference to the drawings. Upon reading the present specification, a person skilled in the art will readily arrive at various changes and modifications within an obvious range.
For example, the roll for introduction is not; necessarily provided. Moreover, the fusion bonding may not be ultrasonic but of heat sealing.
Therefore, such changes and modifications are deemed to fall within the scope of the present invention, which is defined by the appended claims.
The present invention may be applied to the production of the stretchable laminate that is preferably used for diaper-type and underpants-type disposable wearable articles.
1, 2: Pair of sheets, 10: Stretchable laminate, 1f, 2f: First surface
3: Joint portion, 3f: Fixing part, 31: First joint portion, 32: Second joint; portion, 33: Non-joint portion.
50: Anvil roll, 51: Outer peripheral surface, 52: Ridge (projection strip), 52H: First projection, 52S: Second projection, 52L: Receiving part, 59: Recessed groove
60: Introducing device, 61: First roll (regulation roll), 62: Second roll (guide roll)
70: Fusion device, 71: Horn
Df: Stretching direction, Dp: Crossing direction, F: Elastic member
Q: Carrying groove, G1: First guide groove, G2: Second guide groove
H1, H2: Height, S: Width direction (axis direction)
P: Pleat, W1 to W2: Width
Number | Date | Country | Kind |
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2017-127603 | Jun 2017 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2018/022518 | 6/13/2018 | WO | 00 |