JP2011137262A - Three-dimensionally shaped nonwoven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a three-dimensionally shaped nonwoven fabric, having the unevenness of large undulations, having a beautiful appearance of a press-bonded part, hardly yielding floats, cuts, etc., and having a low diffusibility of liquid. <P>SOLUTION: The three-dimensionally shaped nonwoven fabric 1 formed by using a thermally extensible fiber, having the unevenness in at least one of the surfaces, and having an MD direction which is the direction corresponding to the MD direction in the time of production and a CD direction which is the direction corresponding to the CD direction in the time of production is provided by having linear press-bonded parts 13 where the constituting fibers are press-bonded or adhered at the bottom part of the recessed parts, having many projected parts 16 surrounded by the recessed parts, joining the crossing points of the constituting fibers by a means other than the press-bonding at the parts other than the press-bonded parts, forming many closed regions 18 surrounded by the press-bonded parts 13 and having mutually different positions in the MD direction of two peak points 18a, 18a positioning at both ends of the CD direction of each of the closed regions 18. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a three-dimensionally shaped nonwoven fabric.

Conventionally, as a surface sheet of an absorbent article used for absorption of liquid discharged from the body, such as sanitary napkins, incontinence pads, panty liners, etc., it is worn by forming irregularities on the surface facing the skin side of the nonwoven fabric There is known a technique for preventing mucus and rash by reducing contact between a person's skin and a non-woven cloth. Embossing is widely used as a method for forming irregularities on a nonwoven fabric.
As an embossed non-woven fabric, for example, Patent Document 1 describes a non-woven fabric in which small circular embossed portions are formed in a dotted shape by embossing, and Patent Document 2 includes small circular embossed portions. A nonwoven fabric is described which forms a series of rows and a number of rhombus regions surrounded by the rows.

  Further, the present applicant has previously disclosed a three-dimensionally shaped nonwoven fabric using a heat-extensible fiber having an uneven shape on at least one surface and extending its length by heating as a constituent fiber (patent) Reference 3). In Patent Document 3, in addition to the formation of a small circular embossed portion and a large number of rhombus regions surrounded by the embossed portion, the linear embossed portion includes a large number of rhombus regions surrounded by the embossed portion. It is described that it is formed to be formed.

JP 2005-015946 A JP 2002-187228 A JP 2005-350836 A

The three-dimensionally shaped nonwoven fabric described in Patent Document 3 can increase the undulations of the unevenness as compared with the unevenness formed only by embossing by extending the heat-extensible fiber.
However, in the production of three-dimensionally shaped nonwoven fabric using heat-extensible fibers, when an embossed part (pressure-bonded part) is formed on a nonwoven fabric or fiber web by embossing, When they are individually independent (not closed), the fibers extend in the plane direction and are difficult to rise in the thickness direction. Also, if the embossed portion in a plan view has a small circular shape, the heat-extensible fibers around the embossed portion are stretched to easily cover the contour of the embossed portion and the vicinity thereof, making the embossed portion unclear, In some cases, the drawability of the liquid in the vicinity thereof may be reduced. In addition, when a small circular embossed part is formed, or when a large number of linear embossed parts are formed in multiple rows, liquid flow and liquid spread are likely to occur, and when used as a surface sheet of an absorbent article, It is not preferable from the viewpoint of leakage prevention.

  Further, the present inventors pass a strip-shaped original fabric made of a nonwoven fabric or a fiber web between a pair of rolls of the embossing device, so that a large number of rhombus regions surrounded by the embossed portion of the linear embossed portion are generated. Then, when the three-dimensional shaped non-woven fabric was produced by stretching the heat-extensible fiber, there was a case where the embossed part was floated or cut.

  Therefore, the present invention relates to a three-dimensionally shaped nonwoven fabric having irregularities with large undulations, a pressure-bonded portion that is beautiful to the eye, and is less likely to float or break, and has low liquid diffusibility.

  The present invention is formed using a heat-extensible fiber, and has at least one surface with irregularities, in a direction corresponding to the MD direction during manufacture and a direction corresponding to the CD direction during manufacture. A three-dimensional shaped non-woven fabric having a certain CD direction, which has a linear pressure-bonded portion in which constituent fibers are pressure-bonded or bonded to the bottom of the concave portion, and a large number of convex portions surrounded by the concave portion. The crossing points of the constituent fibers are joined by means other than pressure bonding in a portion other than the pressure bonding portion, and a large number of closed regions surrounded by the pressure bonding portion are formed. The present invention provides a three-dimensional shaped nonwoven fabric in which the positions of two vertices located at both ends in the CD direction are different from each other in the MD direction.

  Further, the present invention is a method for producing a three-dimensionally shaped nonwoven fabric formed using heat-extensible fibers and having irregularities on at least one surface, and a strip-shaped raw material containing heat-extensible fibers is converted into a pair of rolls. And a step of forming a linear pressure-bonded portion in which the constituent fibers are pressure-bonded or bonded to the original fabric, and hot air is blown onto the sheet on which the pressure-bonded portion is formed, In the step of forming the pressure-bonding portion, the method includes the step of stretching the heat-extensible fiber, and the closed regions surrounded by the pressure-bonding portions are positioned at both ends in the CD direction of the respective closed regions. The manufacturing method of the three-dimensional shaping nonwoven fabric formed so that the position of two vertices may shift | deviate to MD direction is provided.

The three-dimensionally shaped non-woven fabric of the present invention has irregularities with large undulations, the pressure-bonded portion is visually beautiful, does not easily float or break, and has little liquid flow or liquid spreading.
According to the method for producing a three-dimensional shaped nonwoven fabric of the present invention, a three-dimensional shaped nonwoven fabric having irregularities with large undulations, a pressure-bonded portion that is visually pleasing, and a low liquid diffusibility, is not floated or cut in the pressure-bonded portion. It can manufacture efficiently, suppressing that it arises.

FIG. 1 is an enlarged plan view showing a part of a three-dimensionally shaped nonwoven fabric according to an embodiment of the present invention as viewed from the side of the concavo-convex surface (a surface having large undulations). It is the II-II line expanded sectional view of FIG. It is a schematic diagram which shows an example of the manufacturing method of the three-dimensionally shaped nonwoven fabric shown in FIG. It is explanatory drawing of the formation pattern of the preferable convex part formed in a sculpture roll. It is a top view which shows the closed area | region in other embodiment of this invention. It is a top view which shows the closed area | region in further another embodiment of this invention. It is a figure which shows the formation pattern of the embossed part formed in the nonwoven fabric of an Example and a comparative example.

The present invention will be described below based on preferred embodiments with reference to the drawings.
The three-dimensional shaped nonwoven fabric 1 which is one embodiment of the three-dimensional shaped nonwoven fabric of the present invention is made of nonwoven fabric, and as shown in FIGS. 1 and 2, linear embossing in which the constituent fibers are pressure-bonded by hot embossing. Part (pressure bonding part) 13.
As shown in FIG. 2, the three-dimensional shaped nonwoven fabric 1 has a two-layer structure in which an upper layer 11 and a lower layer 12 are laminated. In an embossed portion (thermocompression bonding portion) 13, the upper layer 11 and the lower layer 12 The space between them is thermocompression bonded. Further, the embossed portion 13 is formed in a straight line in the plan view of the three-dimensional shaped nonwoven fabric 1.

  As shown in FIG. 1, the three-dimensional shaped nonwoven fabric 1 includes a plurality of first linear embossed portions 13 a formed in parallel with each other at predetermined intervals as linear embossed portions 13, and in parallel with each other. A plurality of second linear embossed portions 13b formed at a predetermined interval, and the first linear embossed portion 13a and the second linear embossed portion 2b form a predetermined angle α. Without crossing each other. The width W1a of the first linear embossed portion 13a and the width W1b of the second linear embossed portion 13b are the same, but the arrangement pitch Pa of the first linear embossed portion 13a is the second linear embossed portion. It is slightly longer than the arrangement pitch Pb of 13b. The arrangement pitches Pa and Pb are distances between the centers of the line widths of the linear embossed portions 13.

In the three-dimensional shaped non-woven fabric 1, at least by forming the linear embossed portion 13 and extending the heat-extensible fibers included as constituent fibers after the formation of the embossed portion 13 during production, On one side, a concave portion 14 having a linear embossed portion 13 at the bottom and a large number of convex portions 16 surrounded by the concave portion 14 are formed.
Moreover, since the 1st linear embossed part 13a and the 2nd linear embossed part 13b are formed in the grid | lattice form as the linear embossed part 13, in the three-dimensional shaped nonwoven fabric 1, this linear embossed part 13b Many closed regions 18, 18... Surrounded by the embossed portion 13 are formed. The closed region 18 has a parallelogram shape close to a rhombus in plan view. The central portion of each closed region 18 is a convex portion 16 that is raised relative to the concave portion 14 surrounding the closed region 18.

  The widths W1a and W1b of the linear embossed portion 13 can be determined as appropriate according to the application of the three-dimensional shaped nonwoven fabric 1, and can be set to about 0.1 to 1.5 mm, for example, 0.3 mm or more. It is preferable from the viewpoint of enhancing the visibility of the embossed portion to improve the beauty of appearance and preventing the embossed portion from floating. The float that occurs in the embossed part is a phenomenon in which the fibers on the embossed part of the nonwoven fabric surface are floated without being firmly fixed where the fibers are supposed to be firmly fused together. For example, it may cause inconveniences such as deterioration of appearance, increase in liquid flow and remaining liquid.

Moreover, it is preferable that arrangement pitch Pa and Pb of the linear embossed part 13 is 4-10 mm, especially 5-8 mm.
W1a, W1b, Pa, and Pb are measured in a direction orthogonal to the direction in which the linear embossed portion 13 extends. The widths W1a and W1b of the linear embossed portion 13 may be changed between the intersection 19 and the intersection 19 between the linear embossed portions 13, but the widths W1a and W1b in that case are the intersection with the intersection 19 Measured at 19 midpoint.

The area of each closed region 18 is preferably ²⁰ to 200 cm ² , more preferably 75 to 200 cm ² from the viewpoint of forming the unevenness height, being less crushed after forming the unevenness, and increasing the strength as the nonwoven fabric. 100 cm ² .
Further, the area ratio of the linear embossed portion 13 is 25% or less, particularly 15% or less, to secure a certain amount of area capable of absorbing the liquid and to ensure a certain level of absorption and to secure the absorption rate. From the viewpoint of preventing liquid flow, it is preferable that the area ratio is 8% or more, particularly 11% or more, in order to ensure the strength of the nonwoven fabric and to improve the liquid suction property (suction force by capillary force). It is preferable from the viewpoint. A method for measuring the area ratio of the embossed portion will be described later in Examples.
Moreover, 0.3-0.8 mm is preferable and, as for the line | wire width of the linear embossed part 13, More preferably, it is 0.3-0.5 mm.

The three-dimensional shaped nonwoven fabric 1 has an MD direction which is a direction corresponding to the MD direction at the time of manufacture and a CD direction which is a direction corresponding to the CD direction.
The MD direction in FIG. 1 is the MD direction of the three-dimensional shaped nonwoven fabric 1, and is the MD direction when the three-dimensional shaped nonwoven fabric is manufactured (the machine direction, the same as the flow direction of the strip-shaped original fabric and the three-dimensional shaped nonwoven fabric). Corresponding direction. The CD direction in FIG. 1 is the CD direction of the three-dimensional shaped non-woven fabric 1, and the CD direction when the three-dimensional shaped non-woven fabric is manufactured (the direction perpendicular to the machine direction, the flow direction of the strip-shaped original fabric or three-dimensional shaped non-woven fabric) Is the direction corresponding to the same direction as the direction orthogonal to.
When the MD direction and CD direction of the three-dimensionally shaped nonwoven fabric are understood from the configuration of the nonwoven fabric and other circumstances that the specific direction is the MD direction when manufacturing it, the specific direction is taken as the MD direction. A direction perpendicular to the specific direction is defined as a CD direction. When the constituent fibers of the nonwoven fabric are oriented in one direction, it is estimated that the one direction is the MD direction.

  When the three-dimensionally shaped nonwoven fabric of the present invention is used as a surface sheet of an absorbent article such as a sanitary napkin, disposable diaper, incontinence pad, etc., the MD direction thereof coincides with the longitudinal direction or the width direction of the absorbent article. It is preferable to incorporate it into a property article, and it is more preferable to incorporate it in the longitudinal direction. The longitudinal direction of sanitary napkins, disposable diapers, incontinence pads, and the like is a direction that coincides with the wearer's front-rear direction (the direction from the abdominal side to the back side through the crotch or the reverse side) when worn.

In the three-dimensional shaped nonwoven fabric 1 of the present embodiment, as shown in FIG. 1, a large number of closed regions 18 having a parallelogram shape in plan view are formed. The parallelograms in the present embodiment have different lengths between one set of opposite sides and another set of opposite sides.
As shown in FIG. 1, each closed region 18 has two vertices 18a and 18a located at both ends in the CD direction and two vertices 18b and 18b located at both ends in the MD direction. The two vertices 18a and 18a located at both ends of the closed region 18 in the CD direction are different from each other in the MD direction. On the other hand, the two vertices 18b and 18b located at both ends of the closed region 18 in the MD direction coincide with each other in the CD direction.

  In the three-dimensional shaped nonwoven fabric 1 of the present embodiment, the parallelogram-shaped closed region 18 described above is formed without a gap, and the closed regions 18 face each other at the vertices 18a, 18a located at both ends in the CD direction. A continuous CD-direction region row Rc and a closed region 18 are formed by abutting the vertices 18b and 18b located at both ends in the MD direction to connect the MD-direction region row Rd. The vertices 18a and 18a of the closed region 18 constituting the region row Rc in the CD direction are arranged on a straight line L1 having an inclination angle θ with respect to the straight line L parallel to the CD direction, and constitute the region row Rd in the MD direction. The apexes 18b and 18b of the closed region 18 are arranged on a straight line L2 parallel to a straight line parallel to the MD direction.

Thus, the three-dimensional shaped nonwoven fabric 1 of this embodiment is different from each other in the MD direction of the two vertices 18a, 18a located at both ends of the closed region 18 in the CD direction. The area where the convex part of the engraving roll used when embossing the belt-shaped raw material made of such a laminate is in contact with the opposing flat roll is always made uniform in the circumferential direction of the roll (reduction of the difference) )can do.
Since the pressure applied to the actual embossed portion is obtained by dividing the pressure applied to the entire embossed roll by the embossing that actually contacts, in the conventional technique, the intersection 19 portion of the linear embossed portion 13 is compared to the other portions. Since the contact area is relatively small, the pressure is too strong and the vicinity is cut or the pressure between the intersecting points 19 of the linear embossed portion 13 is insufficient, and the surface fiber of the portion floats. Can be prevented by making uniform as described above.

  The inclination angle θ of the straight line L1 (see FIG. 1) connecting the two vertices 18a, 18a at both ends in the CD direction of each closed region 18 with respect to the straight line L parallel to the CD direction is, for example, 0.01 to 10 °. However, from the viewpoint of preventing the embossed portion 13 from being lifted or cut, and from the viewpoint of not giving an uncomfortable appearance when used, the angle is preferably 0.01 to 5 °, more preferably 0. .5 to 2 °.

  Moreover, in the three-dimensional shaped nonwoven fabric 1 of this embodiment, since the position of the two vertexes 18b and 18b located in the both ends of MD direction of each closed region 18 corresponds in the CD direction, this three-dimensional shaped nonwoven fabric is used. When used as a surface sheet of an absorbent article, the inclination of the emboss pattern is not easily recognized by consumers or the like.

The three-dimensional shaped non-woven fabric 1 includes a heat-extensible fiber as a constituent fiber. The heat-extensible fiber is preferably a heat-fusible fiber.
The heat-fusible fiber as the heat-extensible fiber is preferably a composite fiber composed of a low-melting-point resin component that is a heat-fusion component and a high-melting-point resin component having a higher melting point than the low-melting-point resin component, more preferably A core-sheath type composite fiber having a low melting point resin component as a sheath and a high melting point resin component as a core is used. The low melting point resin component and the high melting point resin component are preferably thermoplastic resins. Examples of the low melting point resin component include polyethylene, polypropylene, polybutene-1, polypentene-1, or a random or block copolymer thereof. Examples of the high melting point resin component include polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon-6 and nylon-66, and the like.
Preferred combinations of the low melting point resin component and the high melting point resin component include polyethylene and polyethylene terephthalate, polyethylene and polypropylene, low melting point polyethylene terephthalate and polyethylene terephthalate, polyethylene and polybutylene terephthalate, etc., but are not limited thereto. is not. The core-sheath type composite fiber may be a concentric type, an eccentric type, or a fiber having a core component exposed at a part of the entire circumference of the fiber.

  It is preferable that the heat-fusible fiber is a heat-extensible composite fiber from the viewpoint of forming a concavo-convex shape. The heat-extensible composite fiber is a fiber whose length is extended by heating, and is a fiber that extends at a temperature of 90 ° C. or higher, preferably 110 ° C. to 130 ° C. The heat-extensible conjugate fiber can cause unevenness with large undulations by being stretched during the production of the three-dimensionally shaped nonwoven fabric, particularly by stretching after the formation of the linear pressure-bonding portion. Therefore, after the extensible fiber is completed as a three-dimensionally shaped nonwoven fabric, most of the stretchable fiber is in a stretched state, and does not necessarily mean a fiber that is further stretched from that state.

Examples of the heat-stretchable composite fiber include a fiber that changes in the crystalline state of the resin by heating or is stretched, or a fiber that has been crimped and has an apparent length that is released by crimping. .
As the heat-extensible composite fiber, the thermal elongation rate at a temperature 10 ° C. higher than the melting point of the low-melting resin component, and at a temperature 10 ° C. higher than the softening point in the case of a resin having no melting point, 3 to 20%, especially 5 to 20% is preferable from the viewpoint of forming an uneven shape having a large undulation. Preferable examples of the heat-extensible conjugate fiber are described in paragraphs [0024] to [0040] of JP-A-2005-350836.
The melting points of the melting point resin component and the high melting point resin component were determined by thermal analysis of a finely cut fiber sample (sample weight 2 mg) using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.) at a heating rate of 10 ° C./min. The melting peak temperature of each resin is measured and defined by the melting peak temperature. A case where the melting point of the low melting point resin component cannot be clearly measured by this method is defined as a resin having no melting point. In this case, the temperature at which the low melting point resin component fuses to such an extent that the fiber fusion point strength can be measured is defined as the softening point.
The thermal elongation rate of the fiber is measured by the following method. A thermomechanical analyzer TMA / SS6000 manufactured by Seiko Instruments Inc. is used. As a sample, after preparing a plurality of fibers having a fiber length of 10 mm or more so that the total weight per 10 mm of the fiber length is 0.5 mg, and arranging the plurality of fibers in parallel, Mount on the device with 10mm distance between chucks The measurement start temperature is 25 ° C., and the temperature is increased at a temperature increase rate of 5 ° C./min with a constant load of 0.73 mN / dtex applied. The elongation amount of the fiber at that time is measured, and the elongation amount Xmm at a temperature 10 ° C. higher than the melting point of the second resin component, and in the case of a resin having no melting point, is read 10 ° C. higher than the softening point.
The thermal elongation rate of the fiber is calculated from (X / 10) × 100 [%].

  The blending ratio of the heat-extensible heat-fusible fiber, particularly the heat-extensible composite fiber, is preferably 40 to 100% by mass, more preferably 70 to 100% by mass in the constituent fibers of the three-dimensionally shaped nonwoven fabric. More preferably, it is 95-100 mass%. Examples of fibers to be blended in addition to these composite fibers include fibers made of thermoplastic resins (non-composite fibers). Moreover, when forming the three-dimensional shaped nonwoven fabric of a multilayer structure, it is also preferable to make the mixture ratio of the heat | fever extensible composite fiber in the layer containing many heat | fever extensible conjugate fibers into said range.

  Below, the preferable manufacturing method of the three-dimensional shaping nonwoven fabric 1 using this heat | fever extensible composite fiber is demonstrated, referring FIG.

First, a web 12A serving as a raw fabric of the lower layer 12 is produced using a predetermined web forming means (not shown). It is preferable that the web 12A does not contain a heat-extensible composite fiber or other heat-extensible fibers, or contains a heat-extensible composite fiber or other heat-extensible fibers in a lower ratio than the upper layer. Separately from the web 12 </ b> A for the lower layer 12, a web 11 </ b> A serving as a raw fabric of the upper layer 11 is produced using a predetermined web forming means (not shown). The web 11A preferably contains a heat-extensible conjugate fiber or is made of a heat-extensible conjugate fiber.
Examples of the web forming means include (a) a card method in which short fibers are opened using a card machine, and (b) a method in which melt-spun continuous filaments are directly pulled by air soccer and deposited on a net (spunbond). And (c) a known method such as a method (air array method) in which short fibers are transported in an air stream and deposited on a net.

  Then, the web 12 </ b> A for the lower layer 12 and the web 11 </ b> A for the upper layer 11 are overlapped and introduced into the heat embossing device 21. And in the heat embossing apparatus 21, heat embossing is integrally performed with respect to both the webs 12A and 11A of the piled-up state. The heat embossing device 21 includes a pair of rolls 22 and 23. The roll 22 is a smooth roll having a smooth peripheral surface. On the other hand, the roll 23 is an engraving roll in which a convex portion having a shape corresponding to the linear embossed portion 13 is formed on the peripheral surface thereof. Each roll 22, 23 can be heated to a predetermined temperature.

  The roll 23 which is a sculpture roll uses a pattern in which convex portions for pressing are formed in the pattern shown in FIG. FIG. 4 is a view showing a part of the developed roll peripheral surface, and the MD direction in FIG. 4 is the roll circumferential direction corresponding to the MD direction of the three-dimensional shaped nonwoven fabric 1, and the CD direction in FIG. Is the axial length direction of the roll corresponding to the CD direction of the three-dimensionally shaped nonwoven fabric 1.

The convex formation pattern (embossing pattern) shown in FIG. 4 is a pattern in which a parallelogram-shaped convex portion 23T surrounds the concave portion, and the parallelogram-shaped convex portion 23T has a roll axis length direction (CD direction). ) When the separation distance in the roll circumferential direction (MD direction) of the vertices 23a, 23a located at both ends of L) is L4, and the separation distance in the roll axis length direction (CD direction) of the vertices 23a, 23a is L5. = An angle θ determined by L4 / L5 is 0.01 to 5 °.
By using the roll 23 in which the convex portions of such a pattern are formed, it is possible to effectively prevent the embossed portion 13 from being floated on the surface fiber and the embossed portion 13 from being cut off.

The heat embossing is performed at a temperature at which the components in the web 12A and / or the web 11A are melted and the web 12A and the web 11A are heat-sealed. The processing temperature for heat embossing is preferably higher than the melting point of the low melting point component and lower than the melting point of the high melting point component in the heat-extensible composite fiber in the web 11A. Moreover, it is preferable to carry out at the temperature below the elongation start temperature of a heat | fever extensible fiber.
By heat embossing, the web 12 </ b> A and the web 11 </ b> A are fixed so as not to be peeled to form the linear embossed portion 13, and the laminated nonwoven fabric 24 in which the upper and lower layers 11, 12 are joined at the linear embossed portion 13 is obtained.

  And the laminated nonwoven fabric 24 in which the embossed part 13 was formed is conveyed to the hot air spraying device 25. In the hot air blowing device 25, the laminated nonwoven fabric 24 is subjected to air through processing. The hot air blowing device 25 is configured such that hot air heated to a predetermined temperature penetrates the laminated nonwoven fabric 24.

  The air-through process is performed at a temperature at which the heat-extensible conjugate fiber in the laminated nonwoven fabric 24 is elongated by heating. And it is performed at the temperature at which the intersection of the heat-extensible composite fibers in a free state existing in the portion other than the embossed portion 13 in the laminated nonwoven fabric 24 is heat-sealed. However, it is preferable that the temperature is lower than the melting point of the high melting point component of the heat-extensible conjugate fiber.

By such an air-through process, the heat-extensible conjugate fiber included in the upper layer 11 extends at a portion other than the embossed portion 13. Since a part of the thermally stretchable conjugate fiber is fixed by the embossed portion 13, the stretched portion is a portion surrounded by the embossed portion 13. Since a part of the thermally stretchable conjugate fiber is fixed by the embossed portion 13, the stretched portion of the stretched thermally stretchable conjugate fiber loses its place in the plane direction of the laminated nonwoven fabric 24, and the non-laminated body 24. Move in the thickness direction. Thereby, convex portions 16 are formed between the embossed portions 13 in the upper layer 11.
Further, the intersections of the heat-extensible composite fibers existing between the embossed portions 13 are joined by heat fusion by air-through processing, and the fiber joined portions 17 are formed in a three-dimensionally dispersed state.
In this way, the desired three-dimensionally shaped nonwoven fabric 1 is obtained.

Since the three-dimensionally shaped nonwoven fabric 1 obtained in this manner has the linear embossed portion 13 formed so that a large number of closed regions 18 are formed, and the heat-extensible fibers are elongated, at least The embossed portion 13 can be visually recognized clearly, and the drawability of the liquid in the embossed portion 13 and its vicinity is good. Moreover, since the liquid flow and the liquid spreading are suppressed by the unevenness and the linear embossed portion 13 having large undulations, the absorbent article is excellent in use as a surface sheet of an absorbent article such as a sanitary napkin. It is possible to give leakage prevention performance.
In addition, since the linear embossed portion 13 is formed in the above-described manner, the embossed portion 13 is unlikely to float or break during its production.

  The three-dimensionally shaped non-woven fabric 1 obtained by the above-described method pressurizes the web 11A for the upper layer 11 on the engraving roll 23 side while applying heat embossing to the webs 11A and 12A. During processing, the upper layer 11 is greatly expanded as compared with the lower layer 12 due to the extension of the heat-extensible fibers, and swells toward the one surface 1a side. Therefore, the depth D1 of the recess 14 on the upper layer 11 side is on the lower layer 12 side. It is deeper than the depth D2 of the recess 15.

The three-dimensionally shaped non-woven fabric of the present invention can be used for various applications, for example, as a surface sheet of an absorbent article.
The absorbent article is mainly used for absorbing and holding excretory body fluids such as urine and menstrual blood. Absorbent articles include, for example, disposable diapers, sanitary napkins, incontinence pads, and the like, but are not limited to these, and widely include articles used to absorb liquid discharged from the human body.
The absorbent article typically includes a top sheet, a back sheet, and a liquid-retaining absorbent body disposed between both sheets. Absorbent articles generally have a skin contact surface that contacts the wearer's skin when worn and a non-skin contact surface directed to the opposite side (usually clothing side such as shorts). The back sheet is disposed on the skin contact surface side, and the back sheet is disposed on the non-skin contact surface side. The three-dimensionally shaped nonwoven fabric according to the present invention is preferably used so that the surface having irregularities, particularly the surface side with large irregularities (in the above embodiment, the upper layer 11 side) faces the wearer's skin.

  As the absorber and the back sheet, materials usually used in the technical field can be used without particular limitation. For example, as the absorbent body, a fiber assembly made of a fiber material such as pulp fiber or a fiber assembly in which an absorbent polymer is held can be coated with a covering sheet such as tissue paper or nonwoven fabric. As the back sheet, a liquid-impermeable or water-repellent sheet such as a thermoplastic resin film or a laminate of the film and a nonwoven fabric can be used. The back sheet may have water vapor permeability. The absorbent article may further include various members according to specific uses of the absorbent article. Such members are known to those skilled in the art. For example, when applying an absorbent article to a disposable diaper or a sanitary napkin, a pair or two or more pairs of three-dimensional guards can be disposed on the left and right sides of the topsheet.

As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to the said embodiment. For example, in the above-described embodiment, heat embossing that is embossing with heat is used to form the embossed portion 13, but embossing without heat, ultrasonic embossing, or high-frequency embossing is used instead. A part can also be formed. Moreover, a pressure-bonding part can also be formed only by the combined use of an adhesive agent and embossing, or an adhesive agent.
Moreover, instead of using the webs 11A and 12A as raw materials for the upper layer 11 and the lower layer 12, a nonwoven fabric may be used for one or both of the three-dimensional shaped nonwoven fabrics. In particular, the lower layer side is preferably made of a nonwoven fabric from the viewpoint of flatness of the lower layer (contactability with the absorber) and ease of formation of the convex shape on the upper layer side by further suppressing the entry of the upper layer fibers.
The three-dimensionally shaped nonwoven fabric may be a single layer nonwoven fabric.

Further, in the closed region 18 of the three-dimensional shaped nonwoven fabric, a straight line L1 (see FIG. 1) connecting the two vertices 18a and 18a located at both ends in the CD direction is inclined with respect to the straight line L parallel to the CD direction. In addition, the straight line L2 (see FIG. 1) connecting the two vertices 18b, 18b located at both ends in the MD direction may be inclined with respect to the straight line L3 parallel to the MD direction [ See FIG. 7A]. In that case, the inclination angle of the straight line L2 with respect to the straight line parallel to the MD direction is preferably 0.01 to 5 °, and more preferably 0.5 to 2 °. Further, the closed region 18 may be a parallelogram having the same length of four sides, that is, a diamond shape.
Further, the linear embossed portion may be a linear embossed portion in which the dot-shaped embossed portions are arranged in a line without a gap.

  In addition, as shown in FIG. 5, a large number of closed regions 18 surrounded by linear pressure-bonding portions may be formed with gaps between them, or as shown in FIG. The top portions 18a at both ends in the CD direction in the region 18A may be formed so as to be positioned between the top portions 18a at the end portions in the CD direction and the top portions 18b at the end portions in the MD direction in the other closed regions 18B. .

EXAMPLES Hereinafter, although this invention is further demonstrated using an Example, this invention is not restrict | limited at all by this Example.
[Example 1]
A heat-stretchable composite fiber (core-sheath type with a core of polypropylene and a sheath of polyethylene) having a fiber diameter of 3.3 dtex and a hydrophilizing agent mainly composed of potassium lauryl phosphate adhered to 0.3% of the fiber weight. The composite fiber) is passed through a card machine to form a web, and the web is introduced into a heat embossing device (that can be processed into an emboss pattern and a flat roll at a predetermined linear pressure, a predetermined temperature, and a predetermined speed), Embossed formed. The embossing roll conditions were an actually measured temperature value of 136 ° C. for both the embossing roll and flat roll, a linear pressure of 60 kgf / cm, and a processing speed of 20 m / min.
Subsequently, the laminated body was introduced into a hot air spraying apparatus, and hot air treatment was performed by air-through processing to obtain a three-dimensional shaped nonwoven fabric having a basis weight of 30 g / m ² .
The formation pattern of the linear embossed part of the obtained three-dimensionally shaped nonwoven fabric is a pattern in which a large number of parallelogram-shaped closed regions are generated as in the pattern shown in FIG. The width W1a (= W1b) of the first and second embossed portions 13, the pattern repeat dimensions [see L6, L7, FIG. 7 (a)], the aspect ratio (L6 / L7), the presence or absence of pattern inclination, the embossed portion The area ratio and the like are shown in Table 1.

[Measurement method of area ratio of embossed part]
The area ratio of the embossed part is measured by the following method. First, using a microscope (manufactured by Keyence Co., Ltd., VHX-900), obtain a surface enlarged photograph of the nonwoven fabric, adjust the scale to this surface enlarged photograph, measure the dimensions of the embossed part, and in the total area Q of the measurement site, The total area P of the embossed part is calculated.
The area ratio of the embossed part can be calculated by the formula (P / Q) × 100.

[Examples 2 to 9, Comparative Examples 1 to 4]
A three-dimensional shaped nonwoven fabric was obtained in the same manner as in Example 1 except that the embossing formed on the nonwoven fabric was changed as shown in Table 1.
In the section of “Pattern Inclination” in Table 1, the CD only X ° is a straight line L1 connecting the apexes at both ends in the CD direction in the closed region of the parallelogram (including the rhombus), and the straight line L parallel to the CD direction. Is inclined by an angle X (inclination angle θ = X °) [see FIG. 1], and CDMD1 ° connects the tops of both ends in the CD direction in a closed region of a parallelogram shape (including a rhombus shape). The straight line L1 is inclined by 1 ° with respect to the straight line L parallel to the CD direction (inclination angle θ = 1 °), and the straight line L2 connecting the tops of both ends in the MD direction in each closed region is changed to a straight line L3 parallel to the MD direction. This means that it is tilted by 1 ° [see FIG. 7 (a)].
In Comparative Example 1, the two diagonal lines of the rhombic closed region are matched with the MD direction and the CD direction at the time of manufacture.

[Evaluation]
The following evaluation was performed about the three-dimensional shaping nonwoven fabric obtained by the Example and the comparative example, and the result was shown in Table 1. In addition, all evaluations are 1 to 5 evaluation points, and the higher the score, the better the evaluation.

[Liquid flow]
〔Method〕
The surface sheet is removed from a commercially available sanitary napkin (trade name “Laurie (registered trademark) with smooth cushion wing” manufactured by Kao Corporation) to obtain a napkin absorbent body. Separately from this, the nonwoven fabric to be measured is cut into MD150 mm × CD50 mm to produce cut pieces. 2 so that the back surface 1b of the non-woven fabric 1 in FIG. 2 faces the napkin absorber at a location (on the skin contact surface of the napkin absorber) where the top sheet was present in the napkin absorber. And fixed with an adhesive. This obtained the sanitary napkin which used the nonwoven fabric of a measuring object as a surface sheet. The test apparatus has a mounting portion in which the mounting surface of the napkin is inclined 45 °. A napkin is placed on the placement portion so that the topsheet faces upward. As a test solution, colored distilled water is dropped onto the napkin at a rate of 1 g / 10 sec. First, the distance from the point where the nonwoven fabric gets wet to the point where the test liquid is first absorbed by the absorbent is measured. The above operation is performed three times, and a value obtained by rounding off the average value of the three rounds to the first decimal place is defined as a liquid flow distance (mm). The liquid flow distance is an index of how much the liquid propagates through the wearer's skin, and the shorter the liquid flow distance, the higher the evaluation. Note that the liquid flow distance exceeding 100 mm is expressed as> 100.

〔Evaluation criteria〕
The score is as follows according to the liquid flow distance (mm).
25mm or less: Score 5
26-50mm: Score 4
51-75mm: Rating 3
76-100mm: Score 2
101mm or more: Score 1
Since each example is a closed pattern, the flowing liquid always touches the emboss, but in the comparative example, the non-closed pattern has a high probability of not touching the emboss, and therefore, an unfavorable result compared to the example. It has become. In addition, the embossing is thought to be one of the reasons that the liquid is difficult to absorb.

[Liquid remaining amount]
〔Method〕
From the sanitary napkin (trade name “Laurie (registered trademark) with smooth cushion wing” manufactured by Kao Corporation), the surface sheet is removed to obtain a napkin absorbent body. Separately from this, the nonwoven fabric to be measured is cut into MD120 mm × CD60 mm to produce a cut piece. 2 so that the back surface 1b of the non-woven fabric 1 in FIG. 2 faces the napkin absorber at a location (on the skin contact surface of the napkin absorber) where the top sheet was present in the napkin absorber. And fixed with an adhesive. This obtained the sanitary napkin which used the nonwoven fabric of a measuring object as a surface sheet. Next, an acrylic plate having a cylindrical transmission hole having a diameter of 10 mm is overlaid on the surface of the obtained sanitary napkin, and a constant load of 100 Pa is applied to the napkin. Under such a load, 3.0 g of defibrinated horse blood is poured from the permeation hole of the acrylic plate. 120 seconds after pouring the horse blood, 3.0 g of defibrinated horse blood is further poured. Acrylic board is removed 60 seconds after injecting a total of 6.0 g of horse blood. Next, the weight (W2) of the nonwoven fabric is measured, and a difference (W2−W1) from the weight (W1) of the nonwoven fabric before pouring horse blood, which has been measured in advance, is calculated. The above operation is performed three times, and the value rounded off to the first decimal place of the average value of the three times is defined as the remaining liquid amount (mg). The liquid remaining amount is an index of how much the wearer's skin gets wet. The smaller the liquid remaining amount, the higher the evaluation.

〔Evaluation criteria〕
The score is as follows according to the remaining amount of liquid (mg).
50 mg or less: Rating 5
51-80mg: Rating 4
81-120mg: Rating 3
120-150 mg: Rating 2
151 mg or more: Score 1
In each of the examples, the emboss is firmly adhered, and since it is a closed type, the thickness is excellent, and as a result, a good liquid remaining amount is realized. On the other hand, in the comparative example, because of the non-closed pattern, the thickness is not so thin or the part is poorly drawn in due to floating on the emboss, so that an unfavorable result can be seen compared to the example.

[Emboss floating]
〔Method〕
The finished non-woven fabric is taken out with a length equal to or greater than the circumference of the emboss and 10 m ² . The embossed portion of this nonwoven fabric is visually observed in detail to confirm whether the embossed portion is lifted. One point is given for each point where the embossed part is lifted. If it is not dotted but floats continuously, it is 10 points for one repeating pattern. The total score of 10m ² is the embossed float index.

〔Evaluation criteria〕
The score is as follows according to the above floating index.
0 or less: Score 5
0-9: Grade 4
10-30: Score 3
30-60: Score 2
61 or higher: Grade 1
In each embodiment, since the emboss pattern is inclined, the linear pressure is almost constant, and there is almost no floating. On the other hand, in Comparative Examples 1 to 3, since the linear pressure is not constant, there is a portion where the embossed portion is cut off, but the other portion is floating. In addition, in Comparative Example 2-3, since each emboss was small and not continuous, the result was more likely to float. In the examples, the line width of 0.5 mm is better than the line width of 0.3 mm.

[Emboss cut]
〔Method〕
The finished non-woven fabric is taken out with a length equal to or greater than the circumference of the emboss and 10 m ² . The embossed portion of this nonwoven fabric is visually observed in detail to confirm whether the embossed portion is lifted. One point is given for each portion where the embossed portion is cut. If the hole is completely open, 10 points. The total score of 10m2 is taken as the embossed float index.

〔Evaluation criteria〕
The score is as follows according to the above floating index.
0 or less: Score 5
0-3: Score 4
3-10: Score 3
10-20: Score 2
21 or higher: Grade 1
In each embodiment, since the emboss pattern is tilted, the linear pressure is almost constant, and there is no cut. In comparison, Comparative Examples 1 and 2 resulted in a cut at a portion where the linear pressure was relatively high.

〔Appearance〕
〔Method〕
Using the finished nonwoven fabric, a napkin was prototyped, and 10 female monitors in the 20s to 40s were given a score for the discomfort of the appearance of the surface material.
No discomfort at all: 5 points, almost no discomfort 4 points, a little discomfort 3 points, discomfort: 2 points, 1 point with very discomfort, rounded to the first decimal place of the average The eye index was used.
〔Evaluation criteria〕
The score is as follows according to the appearance index.
5: Score 5
4: Score 4
3: Score 3
2: Score 2
1: Score 1
Since each embodiment is linear without embossing, an appearance index is a preferable result. When the pattern angle is 1 ° rather than 5 °, the CD alone is less uncomfortable than the CDMD is tilted. On the other hand, in the comparative example, there is embossing floating or the embossing is a small circle shape, so when viewed in cross section, the surrounding fibers are likely to be covered on the upper part of the embossed part, the visibility becomes worse, or the non-closed pattern For this reason, there is little unevenness and the appearance index is not so favorable.

[Liquid spreading]
〔Method〕
From the sanitary napkin (trade name “Laurie (registered trademark) with smooth cushion wing” manufactured by Kao Corporation), the surface sheet is removed to obtain a napkin absorbent body. Separately from this, the nonwoven fabric to be measured is cut into MD120 mm × CD60 mm to produce a cut piece. 2 so that the back surface 1b of the non-woven fabric 1 in FIG. 2 faces the napkin absorber at a location (on the skin contact surface of the napkin absorber) where the top sheet was present in the napkin absorber. And fixed with an adhesive. This obtained the sanitary napkin which used the nonwoven fabric of a measuring object as a surface sheet. Next, an acrylic plate having a cylindrical transmission hole having a diameter of 10 mm is overlaid on the surface of the obtained sanitary napkin, and a constant load of 100 Pa is applied to the napkin. Under such a load, 3.0 g of defibrinated horse blood is poured from the permeation hole of the acrylic plate. 120 seconds after pouring the horse blood, 3.0 g of defibrinated horse blood is further poured. Acrylic board is removed 60 seconds after injecting a total of 6.0 g of horse blood. Next, the surface material was quickly peeled off from the napkin, and the spread area of the liquid on the surface material was measured. As a specific method, a transparent sheet was placed on the surface material, the shape of the liquid spread was copied, and the area was measured. Various methods can be used to measure the area. In this example, the area was measured with an image analyzer. The above operation is performed three times, and the value obtained by rounding off the average value of the three rounds to the first decimal place is defined as the liquid spreading area (cm ² ).

〔Evaluation criteria〕
The score is as follows according to the liquid spreading area (cm ² ).
6 cm ² or less: Rating 5
7-10 cm ² : Rating 4
11-15 cm ² : Rating 3
16-20 cm ² : Rating 2
21cm ² or more: Score 1
In each example, the thickness is sufficient and the emboss pattern is firmly adhered, so that the liquid drawability and the absorption speed are fast and the liquid spread is good. On the other hand, in each comparative example, the embossed part floats, the thickness is small, or the fiber around the embossed part is covered with the embossed part when viewed in cross section, so the liquid drawability becomes worse. Somewhat undesirable results are seen.

[Thickness]
A circular plate is placed on the measurement table, and the position of the upper surface of the plate in this state is set as a measurement reference point A. Next, the plate is removed, the non-woven fabric to be measured is placed on the measurement table, and the plate is placed thereon. The position of the upper surface of the plate in this state is B. The thickness of the nonwoven fabric to be measured is determined from the difference between A and B. The size and weight of the plate can be variously changed depending on the purpose of measurement, but here, measurement was performed using a circular plate having a weight of 12.5 g and a diameter of 56.4 mm so that the pressure exerted on the nonwoven fabric by the plate was 49 Pa. . A laser displacement meter (manufactured by Keyence Corporation, CCD laser displacement sensor KL-080) was used as a measuring instrument. Instead of this, a dial gauge thickness gauge may be used. The above operation is performed 10 times, and the value rounded to the second decimal place of the average value of 10 times is defined as thickness (mm).

The score is as follows according to the thickness (mm).
1.8mm or more: Score 5
1.7-1.6 mm: Rating 4
1.5-1.2mm: Rating 3
1.1-0.9 mm: Rating 2
0.8mm or less: Score 1
Since each Example and Comparative Example 1 are closed patterns, they tend to be uneven and are excellent in thickness. On the other hand, since Comparative Example 2-4 is a non-closed pattern, it is difficult to increase the thickness.

〔Comprehensive evaluation〕
Each evaluation of the above liquid flow, liquid residue, emboss float, appearance, liquid spreading, thickness is not preferable if the average point of each evaluation is high, it is preferable for the user to satisfy all without any defects. . Therefore, the minimum score of all the scores in each example was taken as the overall evaluation.
The preferable comprehensive evaluation is 3 or more, more preferably 4 or more, and still more preferably 5 or more.

  From the results shown in Table 1, the three-dimensionally shaped nonwoven fabric (nonwoven fabrics shown in Examples 1 to 9) according to the present invention has an overall evaluation of 3 or more, in particular, Example 1 has an overall evaluation of 5, and Comparative Examples 1 to 4. It turns out that it is superior to the comprehensive evaluation 2 of the non-woven fabric.

DESCRIPTION OF SYMBOLS 1 Three-dimensional shaping nonwoven fabric 11 Upper layer 11A Upper layer web 12 Lower layer 12A Lower layer web 13a 1st linear embossed part (linear embossed part, pressure bonding part)
13b 1st linear embossed part (linear embossed part, pressure bonding part)
14 Concave portion 15 on upper layer side Concave portion 16 on lower layer side 16 Convex portion 17 Fiber joint portion 21 Heat embossing device 22, 23 Roll 24 Laminated nonwoven fabric 25 Hot air spraying device

Claims (5)

It is formed using a heat-extensible fiber, has at least one surface with irregularities, and has an MD direction that is a direction corresponding to the MD direction at the time of manufacture and a CD direction that is a direction corresponding to the CD direction at the time of manufacture. A three-dimensionally shaped nonwoven fabric having
The bottom of the recess has a linear pressure-bonded portion where the constituent fibers are pressure-bonded or bonded, and has a large number of protrusions surrounded by the recess,
The intersection of the constituent fibers is joined by means other than pressure bonding in a portion other than the pressure bonding portion,
A three-dimensional shaped non-woven fabric in which a number of closed regions surrounded by the pressure-bonding portions are formed, and the positions of two vertices located at both ends in the CD direction of the closed regions are different from each other in the MD direction.   The three-dimensionally shaped nonwoven fabric according to claim 1, wherein two vertices located at both ends in the MD direction of each of the closed regions have the same position in the CD direction.   The three-dimensionally shaped nonwoven fabric according to claim 1 or 2, wherein the pressure-bonded portion has a line width of 0.3 to 0.8 mm.   The inclination angle θ of a straight line connecting two vertices positioned at both ends in the CD direction of each closed region with respect to a straight line parallel to the CD direction is 0.01 to 5 °. The three-dimensionally shaped nonwoven fabric described. A method for producing a three-dimensionally shaped nonwoven fabric formed using heat-extensible fibers and having irregularities on at least one surface,
A step of introducing a strip-shaped original fabric containing a heat-extensible fiber into an embossing device having a pair of rolls, and forming a linear pressure-bonding portion on which the constituent fibers are bonded or bonded to the original fabric; And a step of blowing hot air to the sheet on which the pressure-bonding portion is formed, and extending the thermally stretchable fiber,
In the step of forming the pressure-bonding portion, a closed region surrounded by the pressure-bonding portion is formed so that the positions of two vertices located at both ends in the CD direction of each of the closed regions are shifted in the MD direction. A method for producing a three-dimensionally shaped nonwoven fabric.

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