JP2007130819A - Composite sheet and its production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite sheet which is excellent in expansion/contraction properties and in which functions corresponding to a held functional material are developed uniformly. <P>SOLUTION: In the composite sheet 1, a first sheet 2 having gas permeability is joined partially to a second sheet 3 to form numbers of joining parts 4, an elastomer 6 is arranged between the first sheet 2 in which projections 5 are formed in parts other than the joining parts 4 and the second sheet 3, and the functional material 7 is arranged in the projections 5. The functional material 7 is preferably an absorbent polymer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a composite sheet and a method for producing the same, and more particularly, to a composite sheet suitable for a sheet having various functions such as a constituent member of an absorbent article such as a disposable diaper and a cleaning sheet, and a method for producing the same.

  As a conventional technique related to a composite sheet in which an uneven shape is formed on one of two sheets to be joined and an absorbent polymer or fiber is held in the formed recess, for example, the techniques described in Patent Documents 1 and 2 below are known. It has been.

Japanese Patent Laid-Open No. 6-190002 Japanese National Patent Publication No. 11-502741

  By the way, such a composite sheet may be desired to have elasticity depending on the application to which it is applied.

  Accordingly, an object of the present invention is to provide a composite sheet that is excellent in stretchability and that uniformly expresses a function corresponding to the functional material being held.

  The present invention provides a composite in which a first sheet having air permeability is partially bonded to a second sheet to form a large number of bonded portions, and convex portions are formed at portions other than the bonded portions. The object is achieved by providing a composite sheet that is stretchable and has a functional material in the convex portion.

  Further, in the present invention, as a preferred method for producing the composite sheet of the present invention, the first and second rolls having concave and convex shapes meshing with each other on the peripheral surface portion are rotated, and the meshing portion between the rolls has air permeability. 1 sheet is supplied, a suction force is applied to the first sheet to hold the first sheet on the peripheral surface of the first roll, and the first sheet is moved from the meshing portion of the rolls. Moving, supplying the functional material toward the first sheet held by the first roll, holding the functional material on the first sheet with the suction force through the first sheet, and The second sheet is joined to one sheet, the elastic material is supplied between the two sheets, the first sheet and the second sheet are partially joined, and the two sheets are Bullet There is provided a method of manufacturing a composite sheet for fixing the timber.

  In the present invention, the first and second rolls having concave and convex shapes meshing with each other on the peripheral surface portion are rotated, and the first sheet having air permeability is supplied to the meshing portion between the rolls. The first sheet is held on the peripheral surface of the first roll by applying a suction force to the first roll, the first sheet is moved from the meshing portion of the rolls, and the first roll is held by the first roll. A functional material is supplied toward the first sheet, the functional material is held on the first sheet by the suction force through the first sheet, and the first sheet is made of a stretchable elastic sheet. The present invention provides a composite sheet manufacturing method in which two sheets are merged so as to overlap each other and the first sheet and the second sheet are partially joined.

  The composite sheet of the present invention is excellent in stretchability, and the function according to the functional material being held is uniformly expressed. Moreover, according to the manufacturing method of the composite sheet of this invention, the composite sheet of this invention which produces the said effect can be manufactured suitably.

  The present invention will be described below based on preferred embodiments with reference to the drawings. FIG. 1 shows one embodiment of the composite sheet of the present invention.

  As shown in FIG. 1, the composite sheet 1 includes a breathable first sheet 2 partially joined to a second sheet 3 to form a large number of joined portions 4, and other than the joined portions 4. The convex part 5 is formed in this part. In the composite sheet 1, a string-like elastic material 6 is disposed between the first sheet 2 and the second sheet 3 along the machine flow direction (MD direction in FIG. 1) at a predetermined interval. At the same time, the functional material 7 is disposed in the convex portion 5.

  As will be described later, the functional material 7 is applied to the first sheet 2 while the first sheet 2 is moved by the first roll by applying a suction force to the first sheet 2 in the manufacturing process of the composite sheet 1. Since the functional material 6 can be sucked through the sheet and the functional material 7 held on the sheet does not penetrate or fall, the air-permeable material may be provided.

  The first sheet 2 is made of a fiber material sheet. It is preferable that this sheet-like material is substantially non-stretchable. By using such a sheet-like material, the composite sheet 1 substantially conforming to the concavo-convex shape of the first and second rolls 11 and 12 described later can be stably and reproduced when forming the concavo-convex shape having a desired dimension. Can be manufactured with good performance. 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 used as a composite sheet constituting a conventionally known absorbent article can be used without particular limitation as long as it has the above-described air permeability and is substantially non-stretchable. be able to. 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 ensuring the strength of the composite sheet and improving the touch. The first sheet 2 is preferably subjected to a hydrophilic treatment using a surfactant or the like.

  The second sheet 3 can be composed of the same sheet-like material as the first sheet 2, and among the sheet-like materials used for the first sheet 2, it is composed of sheet-like materials having different manufacturing methods and materials. You can also An elastic sheet having elasticity can be used for the second sheet. As an elastic sheet, the sheet | seat formed by laminating | stacking and integrating the fiber assembly which has a stretching property on the single side | surface or both surfaces of the sheet | seat which consists of elastomer materials can also be used. As the elastomer material, natural rubber, synthetic rubber such as butadiene and isoprene, and the like are preferably used. As the sheet made of the elastomer material, an elastic film obtained by forming the elastomer material into a film, a sheet obtained by forming an elastic fiber made of the elastomer material into a net shape or a non-woven fabric, and the like are preferably used. As the fiber assembly, thermoplastic polyurethane fiber, highly crimped polyethylene fiber, highly crimped polyester fiber, or the like can be used. Examples of the method for fixing the fiber assembly to the sheet made of the elastomer material include a method for fixing the fiber assembly to the sheet by heat fusion.

The basis weight of the first sheet 2 and the second sheet 3 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 second sheet 3 is preferably 5 to 50 g / m ² , particularly preferably 10 to 30 g / m ² . Total basis weight of the composite sheet 1 including the first sheet 2 and second sheet 3, 15~150g / m ^2, it is particularly preferably 20 to 60 g / m ^2.

  The elastic member 6 is joined to the first and second sheets 2 and 3 at the end portion of the composite sheet, and is not joined to these sheets at other portions and is in a free state. As the elastic material 6, those conventionally used for imparting elasticity to the composite sheet constituting the absorbent article can be used. As the elastic member 6, foams of polyolefins and polyurethanes, and natural rubber are preferable. The elastic material 6 is partially bonded and fixed between the first and second sheets 2 and 3 and is in a contracted state in a normal state. The method for joining the elastic material 6 to the first sheet 2 or the second sheet 3 is not particularly limited, but it is preferable to use an adhesive such as a hot melt adhesive, a joining method such as thermal fusion, ultrasonic bonding, or the like. . There is no restriction | limiting in particular in the form of the elastic material 6, The thing of strip | belt shape etc. which has a predetermined | prescribed width | variety other than the string-like form like this embodiment can be used.

Examples of the functional material 7 include absorbent polymers conventionally used in absorbent articles, liquid retaining materials such as pulp, odor control materials such as activated carbon, amorphous silica, bentonite, or combinations of two or more thereof. The holding amount of the functional material 7 is set according to the constituent member to which the composite sheet 1 is applied, the type of the functional material, the degree of function (efficacy) to be developed, and the like. When using the absorbent polymer or a mixture of the absorbent polymer and pulp as the functional material 7, 5 to 100 g / m ² is preferable.

  In the composite sheet 1, the convex part 5 formed in the first sheet 2 has a rectangular bottom surface (non-joined part between sheets). 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 machine flow direction in the manufacturing process of the composite sheet 1, and coincides with the longitudinal direction of the absorbent article when the composite sheet 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 (CD direction) in FIG.

  In the composite sheet 1, when paying attention to any one convex portion in one row, in the left and right rows adjacent to the row, no convex portion is located at a position adjacent to the one convex portion. . Here, “the convex part is not located at a position adjacent to one convex part” means that the convex part is located at the same position in the adjacent row when attention is paid to one convex part. It means not. 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.

  In the composite sheet 1, the joint portions 4 are arranged so as to be shifted by a half pitch in two adjacent rows. 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 arrangement. Accordingly, the convex portions are similarly arranged in a staggered arrangement.

  By arranging the convex portions 5 and the joint portions 4 in this way, it is possible to uniformly hold the functional material for each fixed amount on the entire surface of the composite sheet, and the functions of the functional material are also uniform on the entire surface of the composite sheet. Can be expressed.

In order to maintain a certain amount of the functional material 7 and to fully exhibit its function, the height 5 (see FIG. 1) of the convex portion 5 is preferably 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 mm. 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 (column direction) is 0.1 to 20 mm, particularly 0.5 to 5 mm. Is preferable.

  The composite sheet 1 thus configured is excellent in stretchability. The stretchability of the composite sheet 1 is preferably 100% or more, more preferably 200% or more. Here, for the stretchability of the composite sheet 1, for example, a sample having a width of 25 mm and a length of 50 mm is prepared using a tensile tester such as Tensilon. The sample is pulled between 50 mm with a load of 1.0 N / 25 mm width, and the sample length after extension is measured as A. The elongation rate at that time is defined as follows in the case of the sample of 50 mm. (A-50) / 50 × 100. That is, (sample length after extension at 1.0 N−sample length before extension) / (sample length before extension) × 100. When the sample length after stretching is 100 mm, the stretching rate is 100%, and when the sample length after stretching is 150 mm, the stretching rate is 200%.

  Moreover, since the uneven | corrugated shape of the 1st sheet | seat 3 is maintained even in the state which reached the maximum elongation, the composite sheet 1 has a low contact pressure with a body and has a good wearing feeling.

  Next, the preferable manufacturing method of the composite sheet 1 of this embodiment is demonstrated, referring drawings. The composite sheet 1 of this embodiment can be manufactured by using, for example, a manufacturing apparatus 10 shown in FIG. The manufacturing apparatus 10 includes a first roll (hereinafter, also simply referred to as a roll) 11 and a second roll (hereinafter also simply referred to as a roll) 12 having a concavo-convex shape that meshes with each other on a peripheral surface portion, and both sheets that are superimposed. 2 and 3 and an anvil roll 13 that sandwiches the elastic material 6 disposed between the roll 12 and a functional material that supplies the functional material 7 to the first sheet that is held and moved by the peripheral surface of the roll 11. Supply means 14.

  As shown in FIG. 3, the roll 11 has a set of two spur gears (hereinafter referred to as a set of spur gears) 16A to 16D with spacers 17A to 17D. Is formed concentrically on the rotary shaft 15 and has a concavo-convex shape corresponding to the concavo-convex shape when the first sheet 2 is held (for the roll 11 shown in FIG. The types of combination gears 16A to 16D are attached to the rotary shaft 15 so as to be adjacent to each other. However, in an actual roll, as in the example described later, depending on the width of the first sheet 2, the combination gears 16A, After repeatedly arranging the combination gears 16B, the combination gears 16C, or the combination gears 16D so as to be bilaterally symmetrical via the spacers 17A to 17D, different types of combination gears are attached. ). The assembled gears 16 </ b> A to 16 </ b> D are attached symmetrically in the width direction of the roll 11. In the roll 11, a gap having a width corresponding to the width of the spacers 17 </ b> A to 17 </ b> D is formed between the assembled gears. Each gear constituting each combination gear has an opening formed at the center thereof, and the rotation shaft 15 is inserted into the opening. Each pair of gears and the rotary shaft 15 has a notch (not shown), and a key (not shown) is inserted into the notch. This prevents idling of each gear.

  In the roll 11, the gears constituting each combination gear (for example, the gears 161 </ b> A and 162 </ b> A in the combination gear 16 </ b> A) have the same tip diameter. As described above, in the roll 11, the gears constituting each group gear are shifted by a half pitch, but the adjacent group gears are adjacent to each other between the adjacent gears (for example, the group gear 16A and the like). The gear pitches of the gears 162A and 161B) adjacent to each other between 16B are arranged to be the same pitch. Each of the rolls 11 corresponds to the uneven shape when the first sheet 2 is held, and convex portions and concave portions are alternately formed along the rotation direction and the width direction.

  A plurality of openings 20 are formed in each gear constituting the combined gear so as to surround a central opening into which the rotary shaft 15 is inserted (in FIG. 3, only the combined gear 16A is shown for convenience). Each opening 20 has the same diameter, and is formed at a position equidistant from the center of each gear. The angles formed by the adjacent openings 20 and the center of the gear are all equal. The number of openings 20 in each gear is the same. Each pair of gears is attached so that the openings 20 in adjacent gears are concentric and communicate with each other. In the state where the assembled gears 16A to 16D are attached to the rotary shaft 15 as described above, a plurality of suction paths that extend in the direction of the rotary shaft 15 are formed such that the opening portions 20 of the respective gears extend along the direction of the rotary shaft 15. 21 is formed inside the roll 11. Each suction path 21 communicates with the gap formed by the spacers 17A to 17D described above.

  The widths of the spacers 17 </ b> A to 17 </ b> D are set so that the gap formed thereby becomes wider as the center of the roll 11 in the width direction is closer. Further, in the roll 11, the total width of the tooth widths of the gears constituting each of the combined gears 16A to 16D and the widths of the spacers 17A to 17D is set to be equal. Therefore, the total width of the tooth widths of the respective gears constituting each of the combined gears 16 </ b> A to 16 </ b> D becomes narrower as the center of the roll 11 in the width direction is closer.

  In the roll 11, a suction path 21 opened in the assembled gear 16 </ b> A at both ends thereof communicates with a suction source (not shown) such as a blower or a vacuum pump. Therefore, when the suction operation is performed by operating the suction source, a suction force is applied substantially evenly according to the width of the gap, and the air is substantially passed through the suction path 21 from both ends of the roll 11 to the center in the width direction. Evenly sucked.

  Although not shown in the drawing, the roll 12 is configured by alternately incorporating spacers and gears so as to mesh with the roll 11, but does not include the suction path 21 like the roll 11.

  The supply means 14 of the functional material 7 is a duct 141 that guides the storage portion (not shown) of the functional material 7 and the functional material 7 supplied from the storage portion to the surface of the first sheet 2 held in an uneven shape. And. The functional material 7 may be dropped by its own weight and supplied to the peripheral surface of the roll 11 by applying the suction force, or may be supplied by blowing air.

  The anvil roll 13 includes heating means (not shown). When the sheets 2 and 3 are sandwiched between the anvil roll 13 and the roll 11 heated by the heating means, the sheets 2 and 3 are heat-sealed and joined together, and the joining portion 4 is It is formed.

  Next, the preferable manufacturing method of the composite sheet 1 of this embodiment is demonstrated, referring FIG. 2 based on the manufacturing method by the said manufacturing apparatus 10. FIG.

  First, the first sheet 2 is supplied to the meshing portion of the rolls 11 and 12 while rotating the rolls 11 and 12, and the first sheet 2 is deformed along the peripheral surface of the roll 11.

  Next, the first sheet 2 is sucked by the roll 11, held as it is on the peripheral surface of the roll 11, and moved from the meshing portion. During this movement, the functional material supplied by the supply means 14 is sucked by the suction force of the roll 11 and is held in the concave portion of the first sheet 2 held in the uneven shape. In the roll 11, the gap formed by the spacers 17 </ b> A to 17 </ b> D becomes wider as it approaches the center in the width direction of the roll 11, so that the suction force acts substantially evenly across the width direction of the roll 11. Therefore, the functional material is also held substantially uniformly in the concave portion of the first sheet 2.

  Further, the roll 11 is rotated, and the second sheet 3 is supplied so as to be superposed on the first sheet 2 between the roll 11 and the anvil roll 13 heated to a predetermined temperature, and elastic between these sheets. The material 6 is supplied in an expanded state. Then, both the sheets 2 and 3 are sandwiched between the roll 11 and the anvil roll 13 and joined by thermal fusion. Instead of joining the first sheet 2 and the second sheet 3 by thermal fusion, they may be joined by bonding with an adhesive or ultrasonic bonding.

  Thereafter, the composite sheet 1 is separated from the roll 11 after the suction force from the roll 11 is released. In this way, the composite sheet 1 in which the functional material 7 is held inside the convex portion 5 and the elastic material 6 is disposed between the sheets is continuously manufactured. And when cut | disconnecting the composite sheet 1, the elastic material 6 is fixed in the said cutting part.

  As described above, according to the composite sheet manufacturing method of the present embodiment, the composite sheet 1 in which stretchability is imparted by the elastic material 6 and the functional material 7 is uniformly arranged inside the convex portion 5 is preferable. Can be manufactured.

  In the composite sheet 1 obtained in this way, the functional material 7 is uniformly held in the cavities inside the convex portions 5 formed in the first sheet 2, so that the composite sheet 1 as a whole is uniform. The function of the functional material 7 can be exhibited.

  The present invention is not limited to the embodiment. For example, in the above-described embodiment, the rows of the convex portions 5 and the joint portions 4 in the composite sheet 1 are arranged so as to be shifted from each other by a half pitch, but may be arranged at a pitch other than the half pitch. The same pitch (same phase) may be used.

  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.

  In the above embodiment, the composite sheet 1 has a two-layer structure of the first sheet 2 and the second sheet 3, but the composite sheet 1 has a predetermined function below the second sheet 3. One or two or more other sheets to be applied may be further laminated and joined.

  Further, in the roll of the embodiment shown in FIG. 3, the assembled gear is configured by two gears with two gears, but these may be provided integrally. Further, the assembled gear can be constituted by three or more gears.

  The composite sheet of the present invention can be applied to various applications by selecting the material of the first sheet, the functional material to be held inside the convex portion, and the like. For example, by selecting a spunbonded nonwoven fabric as the first sheet and an absorbent polymer as the functional material, it can be applied to leg gathers having absorbency.

It is a figure which shows typically one Embodiment of the composite sheet of this invention, (a) is a perspective view, (b) is a fragmentary sectional view. It is a figure which shows typically one Embodiment of the manufacturing apparatus of a composite sheet. It is sectional drawing of the 1st roll shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite sheet 2 1st sheet 3 2nd sheet 4 Joint part 5 Convex part 6 Elastic material 7 Functional material 10 Composite sheet manufacturing apparatus 11 1st roll 12 2nd roll 15 Rotating shafts 16A-16D Combined gear 17A -16D Spacer 20 Opening 21 Suction path

Claims (6)

A composite sheet in which a first sheet having air permeability is partially joined to a second sheet to form a large number of joints, and convex portions are formed in parts other than the joints. ,
A composite sheet having elasticity and having a functional material disposed in the convex portion.   The composite sheet according to claim 1, wherein an elastic material is disposed between the first sheet and the second sheet.   The composite sheet according to claim 1, wherein the second sheet is an elastic sheet having elasticity.   The composite sheet according to claim 1, wherein the functional material is an absorbent polymer.   The first and second rolls having concave and convex shapes that mesh with each other on the peripheral surface portion are rotated, a first sheet having air permeability is supplied to the meshing portion of the rolls, and a suction force is applied to the first sheet. The first sheet is held on the peripheral surface of the first roll, the first sheet is moved from the meshing portion of the rolls, and directed toward the first sheet held by the first roll. The functional material is supplied, the first sheet is held by the first sheet with the suction force, the functional material is held by the first sheet, and the second sheet is merged with the first sheet, A method of manufacturing a composite sheet in which the elastic material is supplied to the first sheet, the first sheet and the second sheet are partially joined, and the elastic material is fixed between the two sheets. The first and second rolls having concave and convex shapes that mesh with each other on the peripheral surface portion are rotated, a first sheet having air permeability is supplied to the meshing portion of the rolls, and a suction force is applied to the first sheet. The first sheet is held on the peripheral surface of the first roll, the first sheet is moved from the meshing portion of the rolls, and directed toward the first sheet held by the first roll. Then, the functional material is supplied, the first sheet is held by the suction force through the first sheet, and the second sheet made of a stretchable elastic sheet is superposed on the first sheet. The composite sheet manufacturing method in which the first sheet and the second sheet are partially joined together.

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