JPH10195746A - Composite elastic sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet exhibiting a high stretchability in one direction by laminating a net-like structural material having a high stretchability in at least one direction with nonwoven fiber webs on one side or both faces of the net-like structural material and bonding and making in one body the net-like structural material and the nonwoven fiber webs with substantially parallel streak-like bonded part with each other. SOLUTION: This composite elastic sheet has a net 1 composed of warp 2 and weft 3 and the weft 3 has a high stretchability because of using an elastomer fiber yarn. Nonwoven fiber webs 4 are laminated on at least one face, preferably both faces of the net 1 and streak-like bonding parts 5 are formed, and the net 1 and the nonwoven fiber webs 4 are made in one body. A part of the bonding parts 5 has a high fiber density and thin thickness because of entanglement of the constituting fibers. However, the nonwoven fiber webs 4 are bulkily laminated in a part other than the bonding part 5, then a face to be contacted with a human body is bulky and exhibits excellent skin touch feeling.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite elastic sheet comprising a reticulated structure and a nonwoven fibrous web and having high elasticity in at least one direction.

[0002]

2. Description of the Related Art Conventionally, as a material suitable for diapers, base cloths for cataplasms, disposable underwear, etc., various composite sheets in which an elastic sheet made of an elastomer material and a nonwoven fabric are integrated have been proposed and put to practical use. ing.

As one form thereof, a composite nonwoven fabric in which a nonwoven web is entangled with a net made of an elastomer material has been proposed, and examples thereof include JP-A-1-148856 and JP-A-4-28059. be able to.

[0004]

Problems to be Solved by the Invention
No. 9 proposes to obtain a nonwoven fabric having a large lateral elongation by combining a nonwoven web with a water jet while the net is stretched in the lateral direction. However, since a special device is required to perform the water jet in the state of being extended in the lateral direction, it is undeniable that the method is disadvantageous in terms of process. There is also a problem that the net may be damaged by the elongation.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to obtain a composite elastic sheet having particularly high elasticity in one direction even when bonded to a nonwoven fiber web in a state where a net is not stretched. Aim.

[0006]

In order to achieve the above object, a composite elastic sheet of the present invention comprises a net-like structure having high elasticity in at least one direction, and a non-woven fiber on one or both sides of the net-like structure. A composite elastic sheet on which a web is laminated, wherein the reticulated structure and the nonwoven fibrous web are joined and integrated by joining portions which are substantially parallel to each other in a streak shape. With such a structure, a sheet having excellent elasticity in one direction can be obtained.

[0007] In the composite elastic sheet, it is preferable that the connecting portions existing in a streak shape substantially parallel to each other are provided in a direction orthogonal to a direction in which the net-like structure has elasticity. With such a structure, it is possible to make maximum use of the stretch characteristics of the network structure.

[0008] In the composite elastic sheet, it is preferable that one direction orthogonal to the net-like structure has relatively high elasticity as compared with the other direction. In particular, it is preferable that the net-like structure has relatively high elasticity in the horizontal direction as compared to the vertical direction when the length direction of the raw material is the vertical direction and the width direction is the horizontal direction. By using such a net-like structure, a composite elastic sheet can be easily manufactured, and dimensional stability in the vertical direction can be maintained even in post-processing.

[0009] In the composite elastic sheet, the connecting portions existing in a streak shape substantially parallel to each other are 2 to 15 mm.
It is preferable to provide at intervals of the range.

[0010] In the composite elastic sheet, it is preferable that the connecting portions existing in a streaks substantially parallel to each other are formed by entanglement of the fibers constituting the nonwoven fibrous web with the mesh structure. .

Further, in the composite elastic sheet, the mesh structure and the nonwoven fiber web may be connected to each other at portions other than the plurality of connecting portions existing in the form of parallel lines. In this case, it is desirable that the degree of the connection be relatively weaker than the connection at the connecting portion existing in a streak shape. With such a structure, it is possible to prevent "fuzziness" and "fuzz" of the nonwoven fiber web.

In the composite elastic sheet, the fibers constituting the nonwoven fibrous web are entangled with the net-like structure at portions other than the connecting portions existing in a streak shape substantially parallel to each other, and both are bonded. Is preferred. In the composite elastic sheet, it is preferable that the entanglement of the fibers constituting the nonwoven fibrous web with the network structure is due to the application of a high-pressure water flow. This is because the entanglement of the fibers imparts a favorable feeling based on the fiber web to the surface to be used, and at the same time, prevents damage to the network structure.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The mesh structure used in the present invention is as follows.
It has excellent elasticity in at least one direction.
Here, the net-like structure mainly means a net in which a grid-like mesh is formed by the striatum as shown in FIG.
The concept includes a net-like open nonwoven fabric, a perforated film in which openings are regularly provided, a coarse knitted fabric, and a woven fabric. When using a net as shown in FIG.
It is desirable to use those in which 2000 denier monofilament lines are arranged in the vertical and horizontal directions at a rate of 2 to 20 filaments / inch. The net structure may be a knotted net or a knotless net. The mesh structure is
Square tailoring is preferred. Further, the net can be constituted by a fiber yarn such as a multifilament, a non-twisted yarn, and a twisted yarn. The preferred fineness of the fiber yarn constituting the net is 1
It is 0 to 2000 denier.

In the present invention, it is necessary that the network structure has elasticity in at least one direction. For example, in the net shown in FIG. 1, the vertical striated body is made of an inelastic material,
If the lateral striated body is made of an elastomeric material, the net has a high elasticity in the lateral direction. If this is used, the composite elastic sheet finally obtained has excellent elasticity in the horizontal direction as compared with the vertical direction. Further, the vertical striated body may be made of an elastomer material, and the horizontal striated body may be made of an inelastic material.

Examples of the inelastic material constituting the net include polyolefins such as polypropylene and polyethylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, nylon 6 and nylon 66.
And the like. Examples of the elastomer material include SEBS (polystyrene / polyethylene butylene / polystyrene) copolymer, SIS (polystyrene / polyisoprene / polystyrene) block copolymer, SEPS (styrene / ethylene / polypropylene / styrene) copolymer, and EVA. Examples thereof include a polyolefin-based elastomer, a polyester-based elastomer, and polyurethane. Among them, SEBS is a particularly preferable material because it has a low elongation modulus and a high elongation recovery property. Examples of the combination of the inelastic material and the elastomer material include polyethylene / SEBS, polypropylene / SEBS, and polyethylene / SIS.

The net may be made of only an elastomer material, in which case it has elasticity in both the vertical and horizontal directions.

Embodiments of the nonwoven fibrous web used in the present invention,
The material, the basis weight, and the like are not particularly limited, and may be appropriately determined according to the use of the finally obtained composite elastic sheet.

However, if the fibers in the web are strongly bonded or entangled in advance, the web and the net-like structure are less likely to be entangled when the integration with the net-like structure is performed by the action of high-pressure water flow. It should be noted that Therefore, in the present invention, a parallel web, a semi-random web, and a random web made of staple fibers can be used, and the use of a parallel web is particularly desirable. Since the parallel-shaped web has an easy stretchability in the transverse direction, a composite elastic sheet having a lower stretch modulus in the transverse direction can be obtained by using this, as compared with the case of using a semi-random web or a random web. .

Examples of the material of the nonwoven fiber web include recycled fibers such as rayon, semi-synthetic fibers such as acetate, polyamide fibers such as nylon 6, nylon 66, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, polyethylene, and the like. Examples thereof include polyolefin fibers such as polypropylene, and one or more of them can be arbitrarily selected and used. For example, if rayon fibers are mixed, a sheet having good water absorption and good touch can be obtained. A bulky and flexible sheet can be obtained by using a side-by-side type composite fiber or an eccentric core-sheath type composite fiber made of two types of thermoplastic resins having different melting points to express its three-dimensional crimp. The preferred fineness of the fibers constituting the nonwoven fibrous web is 1 to 10 denier, preferably 1 to 5 denier.

The basis weight of the nonwoven fibrous web is determined according to the type of the network structure to be used, the method of bonding to the network structure, the use of the finally obtained composite elastic sheet, and the like. For example, when a net is used as a net-like structure and the integration process is performed by the action of a high-pressure water flow, a net of 10 to 80 g / m ² may be laminated on one side or both sides of the net.

In order to achieve the object of the present invention, at the time of laminating, by combining a non-woven fiber web with a network structure serving as a base material, the inherent elasticity of the network structure is minimized. It is important to have a proper structure. For that purpose, the web to be compounded has a structure that is easy to extend following the movement of the network,
A part to be combined is only partially connected to provide an unconnected part and a bonded part, and the bonded part is distributed at intervals within a range that does not hinder expansion and contraction of the elastic body, or is bonded to the entire surface. In such a case, it is necessary to provide a structure in which a strong bonding portion and a weak bonding portion that does not impair the elasticity coexist at a certain interval.

Therefore, the composite elastic sheet of the present invention needs to have a structure in which the reticulated structure and the nonwoven fibrous web are integrated at a plurality of mutually parallel streaked joints. In addition, the present invention includes a sheet in which the two portions are bonded to each other even in a portion other than the connecting portion, and the degree of the bonding is relatively weaker than the bonding in the streak-like connecting portion. Hereinafter, a method of bonding the network structure and the nonwoven fiber web will be described.

As a method for forming a plurality of parallel streaked joints, a high-pressure water flow from a nozzle in which orifices having a hole diameter of 0.05 to 0.5 mm are formed at regular intervals in the width direction. Is preferably used to entangle the fibers in the nonwoven fibrous web with the network structure. The high pressure water flow allows the integration of the network and the nonwoven fibrous web without damaging the network.

At this time, the interval between the orifices is the same as the interval between the coupling portions. In the present invention, the distance between the orifices is preferably 2 to 15 mm. If it is less than 2 mm, it is impossible to obtain a sheet having the desired elastic properties of the present invention, and if it exceeds 15 mm, the ratio of the bonding portion occupying a certain area becomes too small, and the two are not sufficiently integrated, which is not preferable. More preferably, it is 3 to 10 mm.

The water pressure at the time of injecting the water stream may be set according to the type of the net-like structure or the material of the nonwoven fibrous web, so that the degree of connection between the two becomes desired. 60 kg
By injecting a water flow of / cm ² or more, the integration of the two can be achieved in most cases.

It is desirable that the connecting portion existing in a streak shape is formed in a direction perpendicular to the direction in which the network structure has elasticity. When forming the joining portion in the vertical direction by the above high-pressure water flow method, if a mesh structure having a high elasticity in the horizontal direction compared to the vertical direction, rich in the elasticity in the horizontal direction,
A composite elastic sheet having a low transverse extension modulus can be obtained.

In the case where the reticulated structure and the nonwoven fibrous web are bonded and integrated only at the connecting portion existing in a streak shape, if the nonwoven fibrous web with almost no entanglement or joining of the fibers is used, the streaks are reduced. “Fuzz” and “hair loss” occur in portions other than the joints existing in the shape, and the composite elastic sheet is inferior in practical use. In order to avoid such inconveniences, it is desirable to bond the net-like structure and the nonwoven fibrous web even in a portion other than the stitch-like connecting portion. However, the degree of the connection must be relatively weaker than the degree of the connection in the streak-like connecting portion. If the bonding at a portion other than the streaked bonding portion is strong, the elasticity of the entire composite elastic sheet decreases, and the elongation modulus also increases. In addition, in the case where the nonwoven fiber web is laminated on both sides of the net-like structure, it is preferable that the webs are bonded to each other at the mesh portion of the net-like structure, because “fluffing” and “hair loss” are more suppressed. .

It is desirable that the connection between the network structure and the nonwoven fibrous web in the portion other than the connection portion existing in the form of a streak is also performed by injection of a high-pressure water flow. In this case, it is preferable to use a nozzle having orifices formed at intervals of about 0.5 to 1.5 mm, and to jet a water stream over the entire object to be processed. In addition, the water pressure at that time is set to be relatively low so that the entanglement between the fibers and the network structure and the entanglement between the fibers do not become too strong. Specifically, it is desirable to be 60 kg / cm ² or less. If the nonwoven fiber web is laminated on both sides of the network structure and subjected to high-pressure water flow treatment, the upper and lower fiber webs will be entangled with each other in the mesh part, which is more effective in suppressing "hair loss" and "fuzz". It is.

The connecting portion existing in the form of a streak may be formed after the network structure and the nonwoven fibrous web are weakly bonded over the whole. Alternatively, after forming the streaked connecting portion, the two may be weakly connected in other portions.

In general, a nonwoven fabric in which fibers are entangled with each other by a high-pressure water stream has a property that the stretchability in the vertical direction is small and the stretchability in the horizontal direction is large. Therefore, a composite elastic sheet in which a net-like structure and a nonwoven fiber web are joined by a high-pressure water flow tends to have a small vertical elasticity and a large horizontal elasticity. When a net or the like having a high elasticity in the horizontal direction is used as the net-like structure, the tendency is further strengthened.
A composite elastic sheet having extremely high elasticity in one direction can be obtained.

As described above, the preferred examples of the joining method include the entanglement of the fibers by a high-pressure water flow. However, under the condition that the mesh structure is not damaged and the elasticity of the mesh structure is not hindered, the heat embossing, ultrasonic wave, Bonding with an adhesive is also possible.

The composite elastic sheet of the present invention thus obtained exhibits excellent stretchability and low elongation modulus in the direction perpendicular to the plurality of parallel streaked joints. . Therefore, the composite elastic sheet of the present invention is suitable for applications requiring elasticity in only one direction, for example, base cloth for cataplasms and waistbands of diapers. Further, since the sheet of the present invention is composed of a net-like structure such as a net and a non-woven fibrous web, the sheet has high air permeability. For example, when used for disposable underwear or diaper side panels, a comfortable wearing feeling is obtained. Can be given.

Next, the present invention will be described more specifically with reference to the drawings. FIG. 1 is an example of a mesh structure (for example, a net) that can be used in an embodiment of the present invention. The net 1 includes a warp 2 and a weft 3. Since the weft yarn 3 uses an elastomer fiber yarn, it has high elasticity. The intersection between the warp yarn 2 and the weft yarn 3 is fixed by means such as fusion or adhesion.
Next, FIG. 2 is a partially cutaway plan view of the composite elastic sheet according to one embodiment of the present invention. The nonwoven fibrous web 4 is laminated on at least one surface, preferably both surfaces, of the net 1 to form streak-like joints 5, and the net 1 and the nonwoven fibrous web 4 are integrated. Next, FIG.
1 shows a sectional view. Since the constituent fibers are entangled with the net, the fiber density is high and the thickness of the joint portion 5 is thin. However, the non-woven fiber web 4 and the net 1 are not connected or relatively weakly connected to each other except for the connecting portion 5, and the non-woven fiber web 4 is bulky and laminated. The surface in contact with is bulky and feels good.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described with reference to embodiments. The physical properties of the obtained composite elastic sheet were evaluated by the following methods. (1) Tensile strength: A specimen having a width of 5 cm and a length of 15 cm with the transverse direction of the composite sheet as a length direction is gripped at a gripping interval of 10 cm, and is stretched at a rate of 30 cm / min using a constant-speed elongation type tensile tester. The load value at the time of elongation and cutting was defined as tensile strength. (2) Elongation modulus: A sample piece having a width of 5 cm and a length of 15 cm with the transverse direction of the composite sheet as the length direction is gripped at intervals of 10 cm.
cm, and stretched by 150% at a speed of 30 cm / min using a constant-speed elongation type tensile tester. From the stress-strain curve (SS curve), 50%, 100%, 15%
The stress at 0% elongation was read, and this was taken as the respective elongation modulus. (3) Residual strain: 150% elongation and relaxation were repeated three times by the same method as the method for measuring the elongation modulus described above, and determined from the SS curve at the third cycle. (4) Thickness: using a thickness measuring instrument (trade name: THICKNESS GAUGE model CR-60A, Daiei Kagaku Seiki Seisakusho Co., Ltd.)
The measurement was performed with a load of 3 g applied per cm ² .

[Preparation of Network Structure] As the network structure,
The longitudinal striatum is a monofilament (denier: 30 denier) of polyethylene resin, the lateral striatum is 42 parts by weight of SEBS resin (G-1657 manufactured by Shell), 46 parts by weight of EVA (ethylene vinyl acetate) resin, And a monofilament having an elasticity of elasticity (fineness: 50 denier) comprising 12 parts by weight of a plasticizer and a net density of 13 filaments / inch in the longitudinal direction and 8 filaments / inch in the horizontal direction. Weight 60 with rich lateral elasticity
A g / m ² net was prepared. This net was produced by arranging a weft thread orthogonal to the warp thread on a warp thread arranged in one direction, and heating to a temperature of 80 ° C. in this state, and fusion-bonding the intersection of the warp thread and the weft thread to integrate.

[Examples 1 and 2] For each example, a parallel web having a basis weight of 25 g / m ² was prepared from the following fibers. This was laminated on both sides of the above-mentioned net, and a water flow of 60 kg / cm ² was jetted once from the upper surface side of the laminated body from a nozzle having orifices having a hole diameter of 0.13 mm at intervals of 0.6 mm, from the lower surface side. Once to make the two integrated.

Next, an orifice having a hole diameter of 0.13 mm
A water flow having a water pressure of 60 kg / cm ² is jetted from the upper surface side of the laminate in a row from nozzles formed at intervals of mm, thereby forming a plurality of streaks that are parallel to each other and formed in the longitudinal direction. An elastic sheet was obtained.

Fiber used Example 1 Eccentric core-sheath type composite fiber whose core / sheath is polypropylene / ethylene propylene random copolymer (fineness: 2d, fiber length: 51 mm) Rayon fiber (fineness: 2d, fiber length: Example 2 Core / sheath type composite fiber with polyester / polyethylene core / sheath (fineness: 2d, fiber length: 51 mm) rayon fiber (fineness: 2d, fiber length) : 51mm) is 7/3 (weight ratio)

[Comparative Examples 1 and 2] For Comparative Example 1, the same fibers as those used in Example 1 were used, and for Comparative Example 2, the same fibers as those used in Example 2 were used.
A parallel web of 5 g / m ² was made. This was laminated on both sides of the net, and a water flow of 50 kg / cm ² was sprayed three times from the upper surface side and two times from the lower surface side of the laminated body from a nozzle provided with orifices having a hole diameter of 0.13 mm at intervals of 0.6 mm. The two were integrated by spraying twice to obtain a composite sheet.

Table 1 shows the physical properties of the composite sheets of Examples and Comparative Examples.

[0041]

[Table 1]

As shown in Table 1, the composite sheets of Examples 1 and 2 exhibited a tensile strength in the transverse direction of Comparative Examples 1 and 2.
However, the elongation modulus is smaller than that of each comparative example. In the examples, the residual strain was small and the elongation recovery was good.

[0043]

As described above, according to the composite elastic sheet of the present invention, a reticulated structure having high elasticity in at least one direction, and a nonwoven fiber web laminated on one or both sides of the reticulated structure. A composite elastic sheet, wherein the reticulated structure and the nonwoven fibrous web are bonded and integrated by a substantially parallel streak-like connecting portion, thereby exhibiting excellent stretchability in one direction. Can be obtained.

Further, the composite elastic sheet of the present invention has a network structure and a nonwoven fibrous web which are bonded at a plurality of parallel streaked bonding portions, and is excellent in a direction orthogonal to the bonding portion. It exhibits excellent elasticity and low elongation modulus, and can be advantageously used as a waistband or side panel of a diaper, a side portion of a sanitary napkin, or a base cloth for a cataplasm due to such elasticity. In addition, when a net-like structure having a high elasticity in the horizontal direction is used, the obtained composite sheet has a property of easily expanding and contracting in the horizontal direction, and has a property of being difficult to elongate in the vertical direction. The productivity at the time of manufacturing can be improved. Further, a one-way stretchable fiber sheet having a small basis weight can be obtained.

[Brief description of the drawings]

FIG. 1 is a net-like structure (net) that can be used in one embodiment of the present invention.

FIG. 2 is a plan view in which a part of the composite elastic sheet of one embodiment of the present invention is broken.

FIG. 3 is a sectional view taken along line II of FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reticulated structure (net) 2 Warp 3 Weft 4 Non-woven fiber web 5 Streaked joint

Claims (9)

[Claims] 1. A composite elastic sheet comprising a network structure having high elasticity in at least one direction and a nonwoven fiber web laminated on one or both sides of the network structure, wherein the network structure and the nonwoven fabric are laminated. A composite elastic sheet, wherein the composite elastic sheet is joined and integrated with the woven fiber web by joints existing in a streak shape substantially parallel to each other. 2. The composite elastic sheet according to claim 1, wherein the connecting portions existing in a streak shape substantially parallel to each other are provided in a direction orthogonal to a direction in which the network structure has elasticity. 3. The reticulated structure according to claim 1, wherein one direction perpendicular to the reticulated structure has relatively high elasticity as compared with the other direction.
3. The composite elastic sheet according to item 1. 4. The net-like structure has a relatively high elasticity in the horizontal direction as compared to the vertical direction when the length direction of the raw material is the vertical direction and the width direction is the horizontal direction. Or the composite elastic sheet according to 2. 5. The composite elastic sheet according to any one of claims 1 to 4, wherein the connecting portions existing in a streak shape substantially parallel to each other are provided at intervals of 2 to 15 mm. 6. The bonding part according to claim 1, wherein the fibers forming the nonwoven fibrous web are entangled with the network structure. 12. The composite elastic sheet according to item 9. 7. The network structure and the nonwoven fiber web are connected to each other at a portion other than the connection portions which are substantially parallel to each other in a streak shape, and the degree of the connection is in the streak shape. The composite elastic sheet according to any one of claims 1 to 6, wherein the composite elastic sheet is weaker than the joint at the joint. 8. The fibers constituting the nonwoven fibrous web are entangled with the net-like structure at the portions other than the connecting portions existing in the form of stripes substantially parallel to each other, and the two are connected.
3. The composite elastic sheet according to item 1. 9. The composite elastic sheet according to claim 6, wherein the entanglement of the fibers constituting the nonwoven fibrous web with the network structure is due to application of a high-pressure water flow.