JP2005245483A - 3D sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a three-dimensional sheet which is rich in flexibility and can form a surface on a base layer side relatively flat. When the three-dimensional sheet is used as a surface sheet of an absorbent article, an absorbent article having a good touch and excellent absorption performance can be obtained.
A three-dimensional sheet of the present invention has a filament layer made of long fiber tows and a base material layer partially joined to form a predetermined pattern joint, and the filament layer is partly on one side. A large number of convex portions are formed protruding. The joint is composed of a large number of small joints 44 arranged discontinuously, and a large number of closed regions 43 surrounded by a plurality of small joints are formed, and the long fibers in each closed region 43 are Substantially all of them are fixed to the small joint portion 44 at the boundary portions 41 and 42 with other closed regions 44 located before and after the orientation direction.
[Selection] Figure 3

Description

  The present invention relates to a three-dimensional sheet having a large number of convex portions.

  It has a liquid-permeable base material and a filament layer provided on the surface of the base material, and both are partially joined to form a plurality of joints, and between the joints and the joints An absorbent article having a surface layer in which a filament is curved to form a loop portion is known (see Patent Document 1).

JP 2002-65736 A

The absorbent article of Patent Document 1 is intended to follow the loop portion of a continuous filament to the body, thereby suppressing irritation to the skin, increasing permeability to the absorption layer, and suppressing liquid return.
However, in the surface layer in the absorbent article of Patent Document 1, the joint between the filament layer and the base material layer is formed in a continuous linear shape, and when the joint is formed by heat sealing or the like, the surface layer itself is It becomes inferior in flexibility, and the touch becomes worse. Further, due to the presence of the continuous linear joining portion, the flatness of the surface on the base material layer side is impaired, and the phenomenon that the surface layer is lifted from the absorber (so-called floating) is likely to occur.

  Accordingly, an object of the present invention is to provide a three-dimensional sheet that is rich in flexibility and capable of forming the surface on the base layer side relatively flat.

  The present invention has a filament layer composed of long fiber tows and a base material layer, and these layers are partially joined to form a joint portion of a predetermined pattern, and the filament layer is partly on one side. It is a three-dimensional sheet that protrudes to the side and forms convex portions of a large number of internal cavities, and the joint portion of the predetermined pattern is composed of a large number of small joint portions that are discontinuously arranged. A plurality of closed regions surrounded by a plurality of small joints are formed, and the long fibers in each closed region are substantially all of the other closed regions located before and after the orientation direction. The object is achieved by providing a three-dimensional sheet that is fixed to the small joint at the boundary.

  The three-dimensional sheet of the present invention is rich in flexibility and can form the surface on the base material layer side relatively flat. Further, a three-dimensional sheet with less distortion and distortion of the entire sheet can be formed. The three-dimensional sheet of the present invention can be used for various applications, but is suitable for a sheet for absorbent articles, particularly for a surface sheet.

The present invention will be described below based on preferred embodiments with reference to the drawings.
As shown in FIGS. 1 to 5, the three-dimensional sheet 1 as an embodiment of the three-dimensional sheet of the present invention includes a filament layer 2 made of long fiber tows and a base material layer 3.
The long fiber tow is an aggregate of a large number of long fibers (filaments), and the long fibers are substantially aligned in the orientation direction.

  The long fibers constituting the filament layer preferably have a fiber diameter of 0.5 to 20 dtex, particularly 1 to 10 dtex from the viewpoint of touch, texture and appearance.

  As shown in FIG. 2, the long fibers 21 constituting the filament layer 2 generally extend in one direction when the three-dimensional sheet 1 is viewed in plan (hereinafter, this direction is referred to as the long fiber orientation direction or the sheet X direction). Also called). The X direction in the three-dimensional sheet 1 of the present embodiment is also the machine direction when the three-dimensional sheet 1 is manufactured.

  The base material layer 3 is comprised from the fiber assembly. The fiber assembly here is a concept including a non-woven fabric.

  The filament layer 2 and the base material layer 3 are partially bonded at a bonding portion having a predetermined pattern. Specifically, as shown in FIG. 2, the filament layer 2 and the base material layer 3 are joined at joints formed in a lattice shape when viewed macroscopically.

The joints of this embodiment are formed in a lattice pattern when viewed macroscopically as shown in FIG. 2, but are arranged discontinuously when viewed microscopically as shown in FIG. It consists of a large number of small joints 44, 44.
The term “discontinuously arranged” means that the small joints are not connected to form a continuous linear joint.
The small joint portion has a length L1 (see FIG. 3) in the longest direction of 0.1 to 30 mm, particularly 0.3 to 15 mm, from the viewpoint of improving flexibility and flatness on the base material layer side. To preferred.

  As shown in FIGS. 2 and 3, a large number of closed regions 43 surrounded by a plurality of small joints 44 are formed in the three-dimensional sheet 1 by joints in a lattice pattern. In the three-dimensional sheet 1 of the present embodiment, a large number of rhomboid closed regions 43 are formed in a form in which the adjacent closed regions 43, 43 are partitioned by intermittent joint lines 41, 42 formed of a set of small joints. Yes. Each closed region 43 is surrounded by a group of small joints, more specifically, an intermittent joint line composed of the small joints.

As shown in FIG. 3, substantially all of the long fibers in each closed region 43 are at boundaries 41 and 42 between other closed regions located before and after the orientation direction (X direction). The small joint 44 is fixed. For example, the long fiber 21a in FIG. 3 has one end side in the orientation direction before and after being fixed to the small joint portion 44a and the other end side to the small joint portion 44a ′, and the long fibers 21c and 21c ′ are respectively One end of the front and rear in the orientation direction is fixed to the small joint 44c, and the other end is fixed to the small joint 44c ′. The long fibers 21b are fixed to the small joint portion 44b on one end and the other end in the orientation direction, and to the small joint portion 44b ′ on the other end side. The long fibers 21c ′ are also fixed to the small joint portion 44b on one end side and the small joint portion 44b ′ on the other end side.
In the present embodiment, the boundary between each closed region and another adjacent closed region is formed by intermittent joint lines 41 and 42.

  The term “substantially all” means that about 10% of the total number of long fibers arranged in the closed region 43 is not fixed either before or after the orientation direction. However, it is preferable that 95% or more of the total number of long fibers arranged in the closed region 43, particularly the total number is fixed both before and after the orientation direction. As an aspect in which the long fibers are fixed to the small joining portion, the long fibers may be fixed to the base material layer 3 or may be fixed to the long fibers fixed to the base material layer.

In the present embodiment, as shown in FIG. 3, the intermittent joint lines 41 and 42 forming the boundary part between the closed regions are each a plurality of small joints 44 that are intermittently arranged in series. The center positions of the small joints in the adjacent joint rows are shifted in a direction (Y direction) perpendicular to the orientation direction of the long fibers, so that The long fibers are fixed at the small joints on both the front and rear sides in the orientation direction.
From the viewpoint of improving flexibility and flatness on the base material layer side, the arrangement pitch P1 (see FIG. 3) of the small joint portions 44 constituting each joint row is 0.15 to 60 mm, particularly 0.5 to 30 mm. Preferably, the distance between adjacent small joints 44a and 44b in each joint row [the spacing in the direction L in which the joint row extends (P1-L1), see FIG. 3] is 0.05 to 30 mm, In particular, the thickness is preferably 0.2 to 15 mm.

  A portion between the fixed portions fixed to the small joint portions 44 in the long fibers 21 in each closed region 43 is not fixed to the base material layer 3 or the other long fibers 21. Then, as shown in FIGS. 1, 4, and 5, the unfixed portion is curved in an arc shape to form a large number of convex portions 5 on one side of the three-dimensional sheet 1. When the convex part 5 pays attention to one convex part, the other convex part is located in the front and rear, right and left. That is, the convex part 5 is discontinuously formed in both directions of the orientation direction (X direction) of the long fibers and the direction (Y direction) perpendicular thereto.

  As described above, in the three-dimensional sheet 1 of the present embodiment, substantially all of the long fibers in the closed region 43 form small junctions that form the boundary between the closed regions 43 on both front and rear sides in the fiber direction. Since the convex part 5 is excellent in shape stability, the long fibers oriented substantially in one direction (X direction) appear neatly on the surface, and the appearance is beautiful. Further, since the long fibers are generally aligned in one direction, the surface is smooth.

  In addition, since the closed region 43 is defined not by a continuous linear joint but by a joint composed of an assembly of small joints, the sheet is flexible and is joined by a gap between the small joints. Since the stress of the part is relieved, it is possible to prevent waviness from occurring on the surface on the base material layer 3 side.

As shown in FIG. 4, the surface on the base material layer 3 side in the three-dimensional sheet 1 of the present embodiment is substantially flat when viewed as a whole, with the portion where the intermittent joining lines 41 and 42 are slightly depressed. is there. Moreover, the site | part in which the intermittent joining lines 41 and 42 were formed, more specifically, the site | part in which the small junction part 44 was formed has thickness smaller and the density larger than the other part.
The three-dimensional sheet 1 of the present invention is not limited to one having a flat surface on the base material layer 3 side. Depending on the application, secondary processing for forming irregularities may be performed.

  The surface on the filament layer 2 side of the three-dimensional sheet 1 has a large number of convex portions 5 as described above, and the portions where the intermittent joining lines 41 and 42 are formed are relatively large. That is, the surface on the filament layer 2 side has irregularities. When used as a surface sheet of an absorbent article that absorbs liquid excreted from the body, the uneven portion can prevent the occurrence of stuffiness and fogging, improve the touch, and the like.

  After joining the filament layer 2 and the base material layer 3, the small joining portion 44 (joint portion in a lattice pattern when viewed macroscopically) in the three-dimensional sheet 1 of the present embodiment is partially heated and heated. It is formed by pressure or ultrasonic embossing.

Next, the manufacturing method of the three-dimensional sheet of this invention is demonstrated taking the case of manufacturing the three-dimensional sheet 1 mentioned above as an example.
First, a filament layer 2 is formed by spreading a long fiber tow to a predetermined width, and a base material layer 3 made of a fiber assembly having heat shrinkability is laminated on the filament layer 2. The fiber aggregate constituting the base material layer 3 may be a web that is not made into a nonwoven fabric or a nonwoven fabric. Further, the filament layer 2 may be formed on the base material layer 3.

  Then, the laminate is subjected to an integration process such as a heat embossing process, an ultrasonic embossing process, or a bonding using an adhesive to integrate the filament layer 2 and the base material layer 3 in the thickness direction. By this integration processing, a lattice-like joint portion as shown in FIG. 2 is formed macroscopically, and a large number of discontinuous small joint portions arranged as shown in FIG. 3 are formed microscopically. For this integration process, an embossing roll, a pressure plate or the like in which a number of small protrusions corresponding to the small joints 44 are preferably arranged in a predetermined pattern is used.

  Then, the laminated body is subjected to a heat treatment by a method such as through air, and the base material layer 3 is thermally contracted. Due to the heat shrinkage of the base material layer 3, the central portion of the long fibers 21 in the closed region 43 rises away from the base material layer 3, and a large number of convex portions 5 having a height are formed. The inside of the convex portion 5 is filled with the fibers on the lower layer side of the filament layer that is not sufficiently raised from the base material layer while being bent. When the base material layer 3 is thermally shrunk, it may be shrunk in both the orientation direction of the long fibers (X direction) and the direction orthogonal to it (Y direction), or only in the X direction using a tenter or the like. It may be shrunk. It is preferable to contract at least in the X direction. It is preferable that the inside of the convex portion 5 is filled with fibers constituting the filament layer and / or the base material layer. From the viewpoint of filling the inside with fibers, the shrinkage of the base material layer 3 is preferably caused to shrink in both the X direction and the Y direction.

The filaments constituting the filament layer 2 and the fibers constituting the substrate layer 3 include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polyamide resins such as nylon, and polymers thereof. And modified products, composite fibers composed of two or more of these (for example, polyethylene / polypropylene composite fibers, polyethylene / polyester composite fibers), cellulosic fibers such as rayon and cotton.
In particular, since the filament layer 2 and / or the base material layer 3 has good adhesion by thermal fusion, thermoplastic fibers such as polyolefin fibers (fibers made of a thermoplastic resin), particularly polyethylene / polypropylene composite fibers, polyethylene / Polyester composite fiber is preferably included. However, thermoplastic fibers such as polyolefin fibers generally have poor absorbency because their surfaces are not hydrophilic. Therefore, when using as a surface sheet for absorbent articles, it is preferable to make the surface hydrophilic with a surfactant or a hydrophilized material so that the surface becomes hydrophilic.

  In particular, the fiber constituting the filament layer 2 is preferably a polyolefin resin, a copolymer thereof, or a modified product in consideration of the bondability with the base material layer, and other polyester-based, polyamide-based, etc. A composite fiber combined with a resin can also be used.

  As the fiber aggregate in the case where the convex portion 5 is formed by thermally shrinking the base layer 3 using the base material layer 3 made of a fiber aggregate having heat shrinkability, the formability and absorbability of the convex portion 5 are used. From the viewpoints of texture and texture, a fiber assembly containing heat-shrinkable fibers can be preferably used.

  As the heat-shrinkable fiber, a heat-crimpable fiber that develops crimps by heat treatment and shrinks is preferable, and a latent crimpable fiber that expresses three-dimensional crimps is particularly preferable. The latent crimpable fiber is composed of, for example, an eccentric core-sheath type composite fiber or a side-by-side type composite fiber containing two types of thermoplastic polymer materials having different shrinkage rates as an example. The thing of 296325 gazette and patent 2759331 gazette is mentioned. For example, a combination of an ethylene-propylene random copolymer (EP) and polypropylene (PP) is preferable from the viewpoint of the softness of the three-dimensional sheet 1 as an example of two types of thermoplastic polymer materials having different shrinkage rates.

When forming a convex part by shrinkage | contraction of the fiber aggregate containing a latent crimpable fiber, the quantity of the latent crimpable fiber contained in the base material layer 3 before heat shrink is the base material layer 3 before heat shrinkage. It is preferably 30% by weight or more, particularly 50 to 100% by weight based on the weight.
When used for the base material layer 3 containing latent crimpable fibers, the three-dimensional sheet 1 obtained by heat shrinking this exhibits good compression recovery properties and stretch recovery properties due to the crimped latent crimpable fibers. Therefore, for example, when used as a surface sheet of an absorbent article, etc., it is preferable because it is excellent in followability to the wearer's movement.

The three-dimensional sheet 1 of the present embodiment can be used for various applications.
For example, it can be particularly preferably used as a surface sheet of an absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and a liquid-retaining absorbent interposed between the two sheets. In that case, it is preferable to arrange the three-dimensional sheet 1 so that the base material layer 3 side faces the absorber 4 side.
Typical examples of such absorbent articles include absorbent articles for absorbing excretory fluids from the body, such as sanitary napkins, panty liners, disposable diapers, urine absorption pads, and breast milk absorption pads.
By using the three-dimensional sheet 1 as a surface sheet of such an absorbent article, an absorbent article having good touch and excellent absorption performance can be obtained.

  In an absorbent article such as a sanitary napkin that is used with its longitudinal direction aligned with the longitudinal direction of the wearer, when the longitudinal direction is aligned with the longitudinal direction (X direction of the three-dimensional sheet), the longitudinal direction While improving the diffusibility of the liquid to a surface, the spreading | diffusion of the liquid to the width direction can be suppressed and side leakage prevention property can be improved.

  Moreover, the three-dimensional sheet 1 of this embodiment can also be used as a wiping sheet or a cleaning sheet. For example, the wiping sheet can be used for cleaning the skin such as the face and buttocks, and the cleaning sheet can be used for cleaning toilets, kitchens, floors, and the like. The wiping sheet or cleaning sheet may be a wet sheet impregnated or coated with a chemical solution or the like, or may be a dry sheet not impregnated with a chemical solution or the like.

As mentioned above, although one Embodiment of this invention was described, this invention is not restrict | limited to embodiment mentioned above.
The pattern of the joint portion viewed macroscopically is not limited to the lattice shape, but may be a closed curved pattern viewed macroscopically, and may be various other patterns that can form a closed region.
For example, a pattern as shown in FIG. 6 may be used. In FIG. 6, a number of regular hexagonal closed regions 43 ′ are formed in the three-dimensional sheet by a large number of small circular joints 44 ′.

  Further, the small joints formed on the three-dimensional sheet may have substantially the same shape as shown in FIGS. 1 and 6, but two or more kinds of small joints having different shapes are combined. May be. FIG. 7 is an example in which one oval small joint portion is provided instead of the three circular small joint portions shown in the circle C shown in FIG. 6. In addition, the shape of a small junction part can be made into an ellipse, a circle, an ellipse, an egg shape, a rectangle, a rhombus, a heart shape, etc.

  The convex portion 5 may be formed as an internal cavity by separating the filament layer 2 from the base material layer 3. The internal cavity can be achieved by adjusting the fiber amount of the filament layer and the rigidity of the fiber, or contracting only in the X direction.

It is a perspective view which abbreviate | omits and shows the solid sheet as one Embodiment of this invention. It is a top view which shows the state which looked at the solid sheet shown in FIG. 1 from the filament layer side. FIG. 3 is a schematic enlarged plan view showing a part of FIG. 2 in an enlarged manner. It is sectional drawing which shows the cross section (cross section which passes along the top part of each of three convex parts) in the solid sheet shown in FIG. 1 along the orientation direction (X direction) of a long fiber. It is sectional drawing which shows the cross section (cross section which passes along the top part of one convex part) along the direction (Y direction) orthogonal to the orientation direction of a long fiber in the solid sheet shown in FIG. It is a schematic plan view which shows the principal part in the solid sheet of other embodiment of this invention. It is an enlarged plan view which shows the principal part in the solid sheet of further another embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Three-dimensional sheet 2 Filament layer 3 Base material layer 44 Small junction part 5 Convex part

Claims (8)

It has a filament layer made of long fiber tows and a base material layer, and these two layers are partially joined to form a joint portion of a predetermined pattern, and the filament layer partially projects to one side. A three-dimensional sheet forming a large number of convex portions,
The joint portion of the predetermined pattern is composed of a large number of small joint portions arranged discontinuously, and the solid sheet is formed with a large number of closed regions surrounded by a plurality of small joint portions,
The three-dimensional sheet in which substantially all of the long fibers in each closed region are fixed to the small joint at a boundary portion with other closed regions located before and after the orientation direction. The three-dimensional sheet according to claim 1, wherein the base material layer includes heat-shrinkable fibers subjected to heat shrinkage. The three-dimensional sheet according to claim 2, wherein the heat-shrinkable fiber is a latent crimpable fiber. The three-dimensional sheet according to any one of claims 1 to 3, wherein the joint portion of the predetermined pattern is formed in a lattice pattern when viewed macroscopically. The joints of the predetermined pattern are composed of intermittent joint lines intersecting each other, and each intermittent joint line is composed of a plurality of joint sections in which a large number of small joint sections are intermittently arranged in series, and adjacent joints. The three-dimensional sheet according to claim 4, wherein the center positions of the small joint portions in the partial row are shifted in a direction orthogonal to the orientation direction of the long fibers. The three-dimensional sheet according to any one of claims 1 to 5, wherein the inside of the plurality of convex portions is filled with fibers constituting the filament layer and / or the base material layer. An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet and a liquid-retaining absorbent interposed between the two sheets,
The absorbent sheet according to claim 1, wherein the surface sheet is arranged such that the base material layer side faces the absorber side. It is a manufacturing method of the solid sheet according to claim 2,
A step of laminating a filament layer made of long fiber tows and a base material layer containing heat-shrinkable fibers, a step of subjecting the laminate to a predetermined bonding treatment to form a bonded portion of the predetermined pattern, and a bonded portion A method for producing a three-dimensional sheet, comprising a step of heat-treating the laminated body on which the base material is formed to thermally shrink the base material layer in at least the same direction as the orientation direction of the long fibers.

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