JP4090420B2 - Top sheet for absorbent articles - Google Patents

Description

  The present invention relates to a top sheet for absorbent articles such as sanitary napkins and disposable diapers, and more particularly to a top sheet having a high liquid leakage prevention effect and a high concealability of absorbed liquid.

  A spunbond nonwoven fabric is point-bonded to at least one side of the elastic material to form a composite nonwoven fabric. After applying a load by pulling the composite nonwoven fabric in a predetermined direction, the load is removed to cause sagging in the spunbond nonwoven fabric. A bulky composite nonwoven fabric is known (see Patent Document 1). This composite nonwoven fabric is used as a side belt of a pants-type diaper.

  However, since this nonwoven fabric produces slack using the plastic deformation of the spunbond nonwoven fabric, fiber fluff is produced in the slack portion. Therefore, when such a nonwoven fabric is used as the top sheet of the absorbent article, the fluffy fibers will irritate the skin and the feeling of wearing the absorbent article will be reduced. In the first place, since this nonwoven fabric is not designed as a top sheet for absorbent articles, a sufficient liquid leakage preventing effect cannot be expected even if it is used as a top sheet for absorbent articles. In particular, it cannot be expected to prevent leakage of loose stool or menstrual blood that is a highly viscous liquid.

  Moreover, since the sagging in the nonwoven fabric is caused by plastic deformation of the spunbonded nonwoven fabric, it is not always easy to produce sagging with a constant size and good reproducibility.

JP-A-5-59655

  Therefore, an object of this invention is to provide the surface sheet for absorbent articles in which the fault which the conventional composite nonwoven fabric mentioned above had was eliminated.

The present invention is a top sheet for absorbent articles used on the skin contact surface of the absorbent article,
The upper layer and the lower layer have an upper layer made of a sheet-like material that is directed to the skin side of the wearer and that does not substantially expand and contract, and a lower layer that is arranged on the absorber side and does not substantially expand and contract. Are joined to each other to form a large number of joints, and the upper layer protrudes toward the wearer's skin side at a portion other than the joints, and a large number of protrusions having a hollow inside. Forming part,
The convex portions and the joint portions are arranged alternately and in a row in one direction, and the rows are arranged in multiple rows,
When paying attention to any one convex portion in one row, in the left and right rows adjacent to the row, the surface for the absorbent article in which the convex portion is not located at a position adjacent to the one convex portion The object is achieved by providing a sheet.

Moreover, as a preferable manufacturing method of the top sheet,
The upper layer is formed at a meshing portion between a first roll having a concavo-convex shape on the peripheral surface and a second roll having a concavo-convex shape meshing with the concavo-convex shape of the first roll on the peripheral surface. The upper layer is unevenly shaped by biting,
The lower layer is overlapped while holding the upper layer in an unevenly shaped state on the peripheral surface of the first roll by suction, and the lower layer is bonded to the upper layer located on the convex portion of the first roll The manufacturing method of the surface sheet for absorbent articles to be performed is provided.

  The surface sheet for absorbent articles of the present invention has excellent liquid leakage prevention properties, particularly high viscosity liquid leakage prevention properties such as soft stool and menstrual blood, and has high concealability of absorbed liquid. .

  The present invention will be described below based on preferred embodiments with reference to the drawings. The principal part enlarged view of the surface sheet for absorbent articles of this invention is shown by FIG. A surface sheet 1 shown in FIG. 1 is used for a skin contact surface of an absorbent article such as a sanitary napkin or a disposable diaper. The topsheet 1 has an upper layer 2 directed to the wearer's skin side and a lower layer 3 disposed on the absorber side. The upper layer 2 and the lower layer 3 are partially joined at a number of joints 4. The upper layer 2 protrudes toward the wearer's skin side at a portion other than the joint portion 4 to form a convex portion 5. The inside of the convex part 5 is hollow.

  In the present embodiment, the bottom surface of the convex portion 5 is rectangular. Further, the convex portion 5 is a flat rectangular parallelepiped or truncated quadrangular pyramid having rounded ridge lines as a whole. On the other hand, the joint 4 is also rectangular.

  The convex portions 5 and the joint portions 4 are arranged alternately and in a row in one direction. In the present embodiment, as shown in FIG. 1, the convex portions 5 and the joint portions 4 are alternately arranged along the X direction in the figure to form a row. This direction coincides with the flow direction in the manufacturing process of the topsheet 1 and also coincides with the longitudinal direction of the absorbent article when the topsheet 1 is incorporated into the absorbent article or a direction perpendicular thereto. The row | line | column which consists of the convex part 5 and the junction part 4 is arrange | positioned at multiple rows over the Y direction in FIG.

  In the topsheet 1, when attention is paid to any one convex portion in one row, no convex portion is located at a position adjacent to the one convex portion in the left and right rows adjacent to the row. . “No convex part is located adjacent to one convex part” means that when one convex part is focused, the convex part is not located at the same position in the adjacent row. I mean. That is, in the Y direction in FIG. 1, it means that the convex portions are not arranged so that the convex portions between adjacent rows are completely connected. Therefore, both a part of a convex part and a part of junction part may exist in the position adjacent to one convex part, or only a junction part may exist. If the convex portions are arranged so as to be completely connected in the Y direction, a convex portion that apparently extends in the Y direction is formed, and in this case, the liquid flows out along the long convex portion. It becomes easy to cause liquid leakage.

  In the present embodiment, in two adjacent rows, the joint portions are arranged so as to be shifted by a half pitch. Therefore, when attention is paid to any one joint portion in one row, the one joint portion is a closed concave portion formed by being surrounded by convex portions on the front and rear sides and the right and left sides. That is, the joints are arranged in a staggered pattern. Accordingly, the convex portions are similarly arranged in a staggered pattern.

  By arranging the convex portion 5 and the joint portion 4 in this manner, liquid leakage is prevented extremely effectively in the absorbent article including the topsheet 1. In detail, when the top sheet 1 is used as a top sheet of a disposable diaper, for example, a diaper for a low-age infant who excretes loose stool, which is a highly viscous excrement, the following effects are exhibited. Since soft stool has a high viscosity, it is generally difficult to permeate the surface sheet quickly and stays on the surface sheet and tends to cause a lateral flow. On the other hand, according to the surface sheet of the present embodiment, the soft stool is trapped in the closed recess formed by being surrounded by the protrusion 5, so that the lateral flow is less likely to occur and is captured. As a result, the downward movement (that is, the absorber direction) is promoted. As a result, leakage of soft stool is prevented. Moreover, since the convex part 5 has a hollow inside, it has a concealing effect that the color of soft stool absorbed by the absorbent body is reduced when viewed from the surface sheet side. These effects are also exhibited when the topsheet 1 of the present embodiment is used as a topsheet for a sanitary napkin for absorbing menstrual blood, which is excrement having high viscosity, as with loose stool.

From the viewpoint of making these effects more remarkable, it is preferable that the height H (see FIG. 1) of the convex portion 5 is 1 to 10 mm, particularly 3 to 6 mm. Moreover, it is preferable that the bottom part dimension A of the convex part 5 along a X direction (column direction) is 2-30 mm, especially 2-5 mm, and the bottom part dimension B along a Y direction (direction orthogonal to a column direction) is 2-2. It is preferably 30 mm, particularly 2 to 5 mm. Moreover, it is preferable that the bottom area of the convex part 5 is 4-900 mm < ² >, especially 4-25 mm < ² >.

  The joint length C (see FIG. 1) of the joint portion 4 in the X direction (row direction) is 0.1 to 20 mm, and particularly 0.5 to 5 mm, and it is difficult for the highly viscous excrement to flow laterally. It is preferable from the point that it can be made and the touch is good and the cushion feeling is high.

  The upper layer 2 and the lower layer 3 are made of a sheet-like material made of the same or different fiber materials. This sheet-like material is substantially non-stretchable. By using such a sheet-like material, the surface sheet 1 substantially conforming to the uneven shape of the first and second uneven rolls described later can be stably and reproducibly formed when forming the uneven shape having a desired dimension. Can be manufactured. The substantially non-stretchable sheet-like material means, for example, an elongation limit of 105% or less, and material elongation or permanent deformation occurs when the elongation limit is exceeded.

  As the sheet-like material, any material that is substantially non-stretchable in a material used as a surface sheet in a conventionally known absorbent article can be used without particular limitation. For example, various nonwoven fabrics such as a nonwoven fabric, a spunbond nonwoven fabric, a meltblown nonwoven fabric, a spunlace nonwoven fabric, and a needle punched nonwoven fabric manufactured by the card method can be used. Moreover, the film etc. which enabled liquid permeation | transmission by the opening means can also be used. When using a nonwoven fabric as the sheet material, the fineness of the constituent fibers is preferably 1 to 20 dtex, particularly 1.5 to 4 dtex, from the viewpoints of securing the strength of the surface sheet and improving the touch. Both the upper layer 2 and the lower layer 3 are preferably subjected to a hydrophilic treatment using a surfactant or the like.

The basis weight of the upper layer 2 is preferably 10 to 100 g / m ² , particularly preferably 10 to 30 g / m ² . On the other hand, the basis weight of the lower layer 3 is preferably 5 to 50 g / m ² , particularly preferably 10 to 30 g / m ² . Total basis weight of the topsheet 1 including the upper 2 and lower 3, 15~150g / m ^2, it is particularly preferably 20 to 60 g / m ^2.

  Next, the preferable manufacturing method of the surface sheet of this embodiment is demonstrated, referring FIG.2 and FIG.3. As shown in FIG. 2, first, the upper layer 2 is unwound from the original fabric 2 ′ of the upper layer 2. Separately, the lower layer 3 is fed out from the raw material 3 ′ of the lower layer 3. Engage the drawn-up upper layer 2 with a first roll having a concavo-convex shape on the peripheral surface and a second roll having a concavo-convex shape meshing with the concavo-convex shape of the first roll on the peripheral surface. The upper layer 2 is unevenly shaped by being bitten into the portion.

  FIG. 3 shows an enlarged view of a main part of the first roll 11. The first roll 11 is formed by combining a plurality of spur gears 11a, 11b,... Having a predetermined tooth width into a roll shape. The tooth width of each gear determines the dimension in the Y direction of the convex portion 5 of the topsheet 1. Adjacent gears are combined such that the pitch of their teeth is shifted by half a pitch. As a result, the peripheral surface of the first roll 11 has an uneven shape.

  A suction hole 13 is formed in the tooth groove portion of each gear in the first roll 11. The tooth groove portion corresponds to a concave portion of the concave and convex shape on the peripheral surface of the first roll 11. The suction hole 13 communicates with a suction source (not shown) such as a blower or a vacuum pump, and suction is performed between the meshing portion of the first roll and the second roll and the joining portion of the upper layer 2 and the lower layer 3. It is controlled to be done. Accordingly, the upper layer 2 formed with unevenness by meshing between the first roll and the second roll is brought into close contact with the peripheral surface of the first roll by the suction force by the suction holes 13, and the uneven shape is maintained. Is done. In this case, as shown in FIG. 3, if a predetermined gap G is provided between adjacent gears, the upper layer 2 is formed in the upper layer 2 without adding an excessive stretching force or a cutting effect due to the uneven engagement of the rolls. It is made to contact | adhere to the surrounding surface of the roll 11 of this. The gap G depends on the total tooth depth of the gear and the basis weight of the upper layer 2. However, if the gap G is 0.1 to 50 mm, particularly about 0.1 to 5 mm, the upper layer 2 can be adhered without breaking or damaging. it can.

  Next, as shown in FIG. 2, the lower layer 3, which is separately fed out, is overlapped with the upper layer 2 kept in close contact with the peripheral surface of the first roll 11. 11 and the anvil roll 14 are clamped. At this time, both the first roll 11 and the anvil roll 14 or only the anvil roll 14 are heated to a predetermined temperature. As a result, the upper layer 2 located on the convex portion of the first roll 11, that is, on the gear teeth, is joined to the lower layer 3 by heat fusion.

  Instead of joining the upper layer 2 and the lower layer 3 by heat fusion, these layers may be joined by bonding with an adhesive or ultrasonic bonding.

  The top sheet 1 shown in FIG. 1 is obtained by the above method. According to this method, unlike the composite nonwoven fabric described in Patent Document 1 described in the section of the prior art, there is an advantage that the convex portion can be formed with a constant size and good reproducibility. In particular, as the first roll 11 and the second roll 12, the combination of gears described above is used, and a gap G (see FIG. 3) having a predetermined width is provided between adjacent gears, whereby the sheet is broken or damaged. The high convex part 5 can be formed without this. Therefore, the obtained surface sheet 1 is not fuzzed, and as a result, the wearer's skin is stimulated and there is no possibility that the feeling of wearing is reduced.

  The surface sheet 1 thus obtained is used for absorbent articles such as disposable diapers, sanitary napkins, and incontinence pads. Absorbent articles generally have a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent disposed between both sheets.

  4 and 5 show another embodiment of the first roll 11. The roll 11 of this embodiment is formed by combining a plurality of first gears 11c and second gears 11d made of spur gears of the same module and attaching these gears concentrically to the rotary shaft 15 to form a roll. It is. Each gear 11c, 11d has the same tooth width. Each gear 11c, 11d has an opening at its center, and the rotation shaft 15 is inserted into the opening. Each gear 11c, 11d and the rotating shaft 15 are each formed with a notch (not shown), and a key (not shown) is inserted into the notch. This prevents idle rotation of the gears 11c and 11d.

  The first gear 11c and the second gear 11d have the same tip diameter. The number of teeth of the first gear 11c is an integral multiple of the number of teeth of the second gear 11d. Specifically, the number of teeth of the second gear 11d used in the present embodiment is 7, whereas the number of teeth of the first gear 11c is 21 which is an integer multiple thereof.

  In the first roll 11, one first gear 11 c is arranged on each side of one second gear 11 d, and a gear group including these three gears as a set. A plurality of 16 are arranged. In each gear group 16, the first gear 11c and the second gear 11d are arranged so that the teeth of the gears 11c and 11d are arranged in parallel in the rotation axis direction of the roll. As a result, in each gear group 16, convex portions 17 and concave portions 18 are alternately formed along the rotation direction of the roll 11. Whether the convex portion 17 is formed by teeth of each of the three gears (that is, the two first gears 11c and the one second gear 11d) arranged in parallel in the rotation axis direction of the roll 11. (Indicated by reference numeral 17a in FIG. 4), or the teeth of the two first gears 11c are formed in parallel in the rotation axis direction of the roll (indicated by reference numeral 17b in FIG. 4). On the other hand, the recess 18 is formed between the teeth of the two first gears 11c. The width of the convex portion 17 determines the dimension in the Y direction of the convex portion 5 of the topsheet 1.

  Two or more sets of gear groups 16 are used. Each gear group 16 is arranged so that the pitches of the concave and convex portions in the adjacent gear groups 16 and 16 are different from each other. In the present embodiment, the adjacent gear groups 16 and 16 have uneven portions shifted by a half pitch.

  In each gear group 16, a plurality of gap portions 19 are formed between the two first gears 11 c along the rotation direction of the roll 11 with a constant interval. Each gap 19 is formed by two first gears 11c and a second gear 11d located between them. More specifically, each gap portion 19 is defined by opposing side surfaces of the two first gears 11c and two adjacent teeth on the second gear 11d. Therefore, the same number of gaps 19 as the teeth of the second gear 11d are formed. The gap portion 19 opens toward the outside in the recess 18 described above.

  A plurality of openings 20 are formed in the first gear 11c so as to surround a central opening into which the rotating shaft 15 is inserted. Each opening 20 has the same diameter, and is formed at a position equidistant from the center of the gear. The angles formed by the adjacent openings 20 and 20 and the center of the gear are all equal. The number of openings 20 in each gear 11c is the same as the number of teeth of the second gear 11d. And when each gear group 16 is assembled | attached, the 1st and 2nd gearwheels 11c and 11d are arrange | positioned so that each opening part 20 may each be located between the adjacent teeth in the 2nd gearwheel 11d. In this state where the gear groups 16 are assembled and the gear groups 16 are arranged so that the pitches of the concavo-convex portions are different from each other, the openings 20 of the first gears 11 c are in the direction of the rotation axis of the roll 11. A plurality of suction paths 21 extending in the direction of the rotation axis are formed inside the roll 11. Each suction path 21 communicates with the gap 19 described above.

  At least one end of the suction path 21 communicates with a suction source (not shown) such as a blower or a vacuum pump. Therefore, when a suction operation is performed by operating the suction source, air is sucked from the gap portion 19 through the suction path 21.

  The roll 11 of this embodiment is particularly effective when a large number of small convex portions are formed with a small pitch. When the roll 11 shown in FIG. 3 is configured by using a low module spur gear that is a gear having a small pitch and a small tooth size, the area of the suction holes 13 that can be formed in the tooth groove portion is reduced. As a result, the force for sucking and holding the upper layer 2 onto the peripheral surface of the roll 11 is reduced, and the formation of stable irregularities is impaired. On the other hand, in the roll 11 of this embodiment, even if a low module spur gear is used, the gap portion 19 can be enlarged by increasing the tooth width of the second gear 11d or reducing the number of teeth. As a result, the area of the suction hole can be sufficiently secured. Furthermore, there is also an advantage that the pitch and size of the convex portions can be freely changed by a simple operation simply by changing the combination and width of the gears.

  The present invention is not limited to the embodiment. For example, in the said embodiment, although the row | line | column of the convex part 5 and the junction part 4 in the surface sheet 1 was arrange | positioned and shifted | deviated from the adjacent row | line by half pitch, if it is not the same pitch (same phase), other than half pitch It may be arranged at a pitch.

  Moreover, in the said embodiment, although it was the recessed part which was enclosed by the convex part 5 and the front and back, and right and left of the junction part 4 were closed, this recessed part is not closed and the one part is connected with the other recessed part. May be.

  Moreover, in the said embodiment, although the surface sheet 1 was the 2 layer structure of the upper layer 2 and the lower layer 3, one or two or more sheets which provide a predetermined function to the surface sheet 1 under the lower layer 3 are provided. Furthermore, you may join.

  Further, for the purpose of further promoting the liquid permeability of the topsheet 1, a liquid introduction hole may be formed by perforating or opening a part of the joint portion, the upper layer 2, or the lower layer 3.

  In addition, the roll of the embodiment shown in FIGS. 4 and 5 has a roll shape in which a plurality of gears are attached to a rotation shaft so as to form uneven portions alternately along the rotation direction of the roll. A gap of a predetermined width is formed between the gears every predetermined number of gears, and the gap communicates with a suction path formed in the first roll so as to extend in the rotation axis direction of the roll. Any form can be used.

  Further, in the roll of the embodiment shown in FIG. 4 and FIG. 5, a set of gear groups is constituted by two first gears 11c and one second gear 11d positioned between them. However, the configuration of the gear group is not limited to this, and at least one first gear 11c is arranged on at least one side of at least one second gear 11d, and thereby a set of gear groups and Can be made.

  Further, in the roll of the embodiment shown in FIGS. 4 and 5, the gap 19 is formed by interposing the second gear 11d between the two first gears 11c. Is not limited to this. For example, the gap may be formed using a gear having a shape in which the second gear 11d is integrated with the first gear 11c.

It is a perspective view which expands and shows the principal part of the surface sheet for absorbent articles of this invention. It is a schematic diagram which shows the method of manufacturing the surface sheet shown in FIG. It is a principal part enlarged view of the 1st roll in FIG. It is a perspective view which shows the principal part of another embodiment of a 1st roll. It is a disassembled perspective view of a part of roll shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Top sheet 2 Upper layer 3 Lower layer 4 Joint part 5 Convex part 11 1st roll 12 2nd roll 13 Suction hole 15 Rotating shaft 16 Gear group 17 Convex part 18 Concave part 19 Cavity part 20 Opening part 21 Suction path

Claims (11)

A surface sheet for absorbent articles used on the skin contact surface of the absorbent article,
The upper layer and the lower layer have an upper layer made of a sheet-like material that is directed to the skin side of the wearer and that does not substantially expand and contract, and a lower layer that is arranged on the absorber side and does not substantially expand and contract. Are joined to each other to form a large number of joints, and the upper layer protrudes toward the wearer's skin side at a portion other than the joints, and a large number of protrusions having a hollow inside. Forming part,
The convex portion has a rectangular bottom surface, and is a flat rectangular parallelepiped or truncated quadrangular pyramid with a rounded ridgeline as a whole,
The convex portions and the joint portions are arranged alternately and in a row in one direction, and the rows are arranged in multiple rows,
When paying attention to any one convex portion in one row, in the left and right rows adjacent to the row, the surface for the absorbent article in which the convex portion is not located at a position adjacent to the one convex portion Sheet.   The top sheet for absorbent articles according to claim 1, wherein when one arbitrary joint portion in the one row is focused, the one joint portion is surrounded by convex portions on the front and rear sides and on the left and right. The height of the convex part is 1 to 10 mm and the bottom area is 4 to 900 mm ² , and the joint part has a length in the column direction of 0.1 to ²⁰ mm. Top sheet for absorbent articles. The top sheet for absorbent articles according to claim 1, wherein the rows of the convex portions and the joint portions are shifted from adjacent rows by a half pitch. In the topsheet, the rows of the protrusions and the joints coincide with the flow direction in the manufacturing process of the topsheet, whereby the two sides of the bottom of the protrusions in the manufacturing process of the topsheet The top sheet for absorbent articles according to any one of claims 1 to 4, wherein the top sheet matches the flow direction and the width direction. It has an upper layer made of a sheet-like material that does not substantially expand and contract and a lower layer made of a sheet-like material that does not substantially expand and contract, and the upper layer and the lower layer are partially joined to form a large number of joints. The upper layer protrudes outward at a portion other than the joint portion to form a large number of convex portions having a hollow inside, and the convex portions and the joint portions are alternately and in one direction. Are arranged so as to form a row, and the rows are arranged in multiple rows,
When paying attention to any one convex portion in one row, in the left and right rows adjacent to the row, the surface for the absorbent article in which the convex portion is not located at a position adjacent to the one convex portion A sheet manufacturing method comprising:
The upper layer is formed at a meshing portion between a first roll having a concavo-convex shape on the peripheral surface and a second roll having a concavo-convex shape meshing with the concavo-convex shape of the first roll on the peripheral surface. The upper layer is unevenly shaped by biting,
The concavo-convex shape is arranged such that a plurality of concavo-convex portions in which convex portions and concave portions are alternately formed along the rotation direction of the roll are shifted from each other so that the pitches of the concavo-convex portions adjacent to each other along the rotation axis direction of the roll are shifted from each other. Has been formed,
The lower layer is overlapped while holding the upper layer in an unevenly shaped state on the peripheral surface of the first roll by suction, and the lower layer is bonded to the upper layer located on the convex portion of the first roll The manufacturing method of the surface sheet for absorbent articles to do. And suction port is provided in the recess in the first roll, according to claim 6, wherein for adhering to the circumferential surface of the first roll remain the upper layer is uneven shaped by performing suction through the suction port Manufacturing method of the surface sheet. The manufacturing method of the surface sheet of Claim 6 or 7 which uses what formed two or more gears each having a predetermined tooth width into a roll shape as the first roll and the second roll. The manufacturing method of the surface sheet of Claim 8 with which the space | gap of the predetermined width is provided between the said adjacent gears. The topsheet according to any one of claims 6 to 9, wherein only the anvil roll is heated to a predetermined temperature when the upper layer and the lower layer are joined by being pressed between the first roll and the anvil roll. Method. An absorbent article having the topsheet according to any one of claims 1 to 5.

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