JP2986569B2 - Elastic nonwoven fabric for surface material of disposable diaper and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a disposable diaper table.
The present invention relates to a stretchable nonwoven fabric suitable for a face material and a method for producing the same.

[0002]

2. Description of the Related Art For example, U.S. Pat. S. P. 3,485,
708. In addition, by applying such a kind of technology, a fiber web composed of a mixture of a heat-crimpable fiber and a non-heat-crimpable fiber is entangled with a fiber, and then subjected to a heat treatment. A technique for obtaining a nonwoven fabric is known from JP-A-63-309,657.

[0003]

A nonwoven fabric containing heat-crimped fibers and entangled with fibers under the action of fluid pressure as described in the above technique generally has elasticity. Like non-stretch non-woven fabric,
Or more useful. In addition, diapers
When used as a surface material , water absorption and moisture absorption are often required. In the case of the prior art, if a nonwoven fabric is manufactured using a fiber web obtained by mixing a hydrophilic fiber such as a pulp fiber or a rayon fiber with a heat-crimpable fiber which is generally hydrophobic, such a need is satisfied. be able to. However, since these hydrophilic fibers are not substantially heat-crimpable and have substantially no elasticity, mixing them with the nonwoven fabric impairs the elasticity that the heat-crimpable fibers should originally provide. Will be. Therefore, the elasticity and water absorbency / hygroscopicity of this nonwoven fabric are not necessarily a trade-off problem, but if it is intended to impart water absorbency / hygroscopicity to the nonwoven fabric, the elasticity tends to be sacrificed. Problem.

Accordingly, the present invention provides a method of laminating and fabricating a non-woven fabric by mainly using hydrophilic fibers for the first fiber web and mainly using heat-crimpable fibers for the second fiber web. , To solve such problems.

[0005]

The gist of the present invention to solve the above problems is as follows.

According to the present invention, a hydrophobic fiber composed of an eccentric sheath-core type or side-by-side conjugate fiber which is crimped to exhibit elasticity and a hydrophilic fiber which does not substantially exhibit elasticity are mixed.
A stretchable nonwoven fabric having a basis weight of 20 to 250 g / m ² formed by entanglement, wherein the nonwoven fabric contains a relatively large amount of the hydrophilic fiber on one surface layer side, and on a back layer side facing the surface layer side. is used, characterized in that are entangled with each other without relying on the elasticity includes many relatively hydrophobic fibers showing a and intervention of these fibers melt or binder
It is in a stretchable nonwoven fabric for the surface material of disposable diapers .

Further, according to the present invention, a fibrous web is entangled with a fiber under the action of jetting a high-pressure fluid, and thereafter, the web is heat-treated to develop a fiber crimp.
A method of manufacturing a stretchable nonwoven fabric / m ^2, a first fiber 30 to 70 wt% consisting of an eccentric sheath-core type or side-by-side type composite fibers showing a stretchable crimped at a given temperature, elasticity Second fibers 30 that do not substantially exhibit
5 to 125 g / m ^{2 based} on a mixture of
The first fiber web and the first fiber 90 to 100% by weight
And a basis weight of 8 to 10% by mixing 0 to 10% by weight of the second fiber.
A second fiber web of 200 g / m ² is laminated and placed on a support at a weight ratio of the first fiber web: the second fiber web = 1: 3 to 3: 1, and the high-pressure fluid is subjected to First
A disposable disposable dispenser characterized by spraying from the fiber web side to act, and then developing the crimp at a given temperature .
A method for producing the nonwoven fabric for a surface material of a diaper .

[0008]

In the nonwoven fabric and the method of manufacturing the same according to the present invention, the nonwoven fabric is formed by entanglement of the first fiber web and the second fiber web in a laminated state. The first fiber web portion can form a hydrophilic surface layer portion on the nonwoven fabric by selecting a hydrophilic fiber as the second fiber. The second fiber web portion contains a relatively large amount of thermally crimped fibers, and can form a highly elastic back layer portion facing the surface layer portion. Such a back layer portion can exert its elasticity to a hydrophilic surface layer portion via fiber entanglement. Therefore, even if the hydrophilic fiber is non-stretchable, if the non-woven fabric according to this manufacturing method,
Compared to a conventional nonwoven fabric in which the same amount of heat-crimped stretchable fiber and non-stretchable hydrophilic fiber are simply mixed, the surface layer is more hydrophilic and the entire nonwoven fabric has more elasticity. A rich nonwoven fabric can be obtained. Therefore,
It is useful as a surface material for disposable diapers.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a schematic process diagram showing an example of a method for producing a nonwoven fabric 1 according to the present invention. This process includes a web supply unit 2, a fluid entanglement process 3, a drying / heat treatment process 4, a winding process 5, and the like.

In the web supply step 2, the first fiber web 6 and the second fiber web 7 are conveyed to conveyors 21 and 22, respectively.
Supplied by In the laminated conveyor 23, the first fiber web 6 is laminated on the second fiber web 7 to form a laminated web 8. The first fiber web 6 has a basis weight of 5 to 125 g / m ^2.
30 to 70% by weight of the first heat-crimpable fiber, and 30% by weight of the non-stretchable second fiber having substantially no heat-crimpability.
It is a fiber mixture that accounts for ~ 70% by weight. A typical example of the heat-crimpable first fiber is a so-called composite fiber in which a two-component polymer is composited in a sheath-core type or a bimetal type. In the case of a sheath-core type, an eccentric sheath-core type is preferable in that crimpability is generally good.
In this embodiment, a bimetallic composite fiber (EP-SH fiber manufactured by Chisso Polypro Fiber Co., Ltd.) composed of polypropylene and modified polypropylene is used. Such a conjugate fiber is crimped when heat-treated at a specific temperature, and the crimped fiber exhibits excellent elasticity, but is generally hydrophobic and poor in water absorption. On the other hand, the non-stretchable second fibers that do not substantially exhibit elasticity include fibers that do not exhibit substantial thermal crimping at the heat treatment temperature at which the first fibers are crimped and that do not exhibit elasticity. . For this, natural fibers such as pulp fibers and rayon fibers and general synthetic fibers can be selected according to the heat treatment temperature. However, in the present invention, the use of natural fibers is preferred for imparting hydrophilicity to the nonwoven fabric 1. In this embodiment, rayon fiber is used. The second fiber web 7 has a basis weight of 8 to 200 g / m ² , and the first fiber is 90 to 100% by weight, and the second fiber is 0 to 10% by weight. More preferably, the first fiber is 1
00% by weight. In the lamination, the weight ratio of the first fiber web 6 to the second fiber web 7 is set in the range of 1: 3 to 3: 1, and the fineness of the first fiber and the second fiber is 0.5 to 6 d (denier). it is our disposable above the nonwoven fabric 1 in the range of le)
Suitable for use as a surface material for diapers .

The web 8 formed by laminating is transferred to a transfer belt 23.
Is transferred to the mesh belt 31 in the confounding process step 3.
In the entanglement processing step 3, high pressure jet water 33 is jetted from the jet nozzle 32 to the laminated web 8 from the first fiber web 6 side, and the fibers constituting the laminated web 8 are entangled with each other.
After the spraying process, the laminated web 8 is sandwiched between dehydration rollers 35 which are vertically arranged, pressed and subjected to dehydration treatment. Mesh belt 31
Is a water receiving tray for draining the jet water 33. The nonwoven fabric in which the fibers are entangled using the injection pressure of the fluid in this way is different from the nonwoven fabric in which the fibers are thermally melted or bonded by a binder, and is extremely flexible and thus is suitable as a surface material of a disposable diaper. is there. The details of the technique of entanglement of the fiber with the fluid can be based on known materials such as the above-cited references.

The laminated web 8 having been subjected to the fiber entanglement treatment is sent to a drying / heat treatment step 4 on a transfer belt 41.
The laminated web 8 is heated at 60 ° C.
After the hot air drying treatment for 0 minutes, the first fibers are crimped in the processing chamber 43 at 120 ° C. for about 10 minutes. The processing chamber 44 is a cooling chamber that blows room temperature air to the laminated web 8. The laminated web 8 that has exited the processing chamber 44 becomes the nonwoven fabric 1 as a finished product.

In the winding step 5, the nonwoven fabric 1 is rolled.
Into a product.

Here, the side of the nonwoven fabric 1 facing the spray nozzle 32 is temporarily referred to as the surface layer side, and the side contacting the mesh belt 31 is referred to as the back layer side. The surface layer side is mainly composed of the first fiber web 6, and the back layer side is mainly composed of the second fiber web 7. Therefore, if non-stretchable but hydrophilic fibers such as pulp fibers and rayon fibers are used as the second fibers, the nonwoven fabric 1 can be made hydrophilic mainly on the surface layer side, and can have high water absorbing power. . In addition, the back layer side is mainly a crimped elastic first fiber, and the second fiber has only 10% by weight at most, so that the original elasticity of the first fiber is exhibited. Moreover, since the fibers of the first fiber web 6 and the second fiber web 7 are entangled and integrated with each other between the surface layer side and the back layer side, the elasticity of the back layer side is easily extended to the surface layer side. And the entire nonwoven fabric 1 has excellent elasticity. However, it may be desirable that the nonwoven fabric 1 has some elasticity on the surface layer side and some water absorbency on the back layer side. For example, if only the back layer expands and contracts, but the surface layer does not expand,
This is because wrinkles and tearing are likely to occur on the surface side, and delamination between the front and back sides may occur. If the water absorption of the back layer is too poor, the water absorption of the surface layer reaches the saturation level immediately, and the dry touch feeling on the surface layer may be easily lost. Therefore, the first fiber web 6 contains 30 to 70% by weight.
Of the first fiber, and 10% by weight of the second fiber web 7
The second fiber is mixed as the upper limit to avoid such a problem as much as possible.

In contrast to the above-described manufacturing method, the second fiber web 7
Is a surface layer side, and there is a manufacturing method in which both webs 6 and 7 are laminated and passed through the entanglement processing step 3 so that the first fiber web 6 is on the back layer side. However, the entanglement of the fibers by the jet water 33 tends to be the densest on the surface side where the jet water 33 directly collides. Therefore, such a manufacturing method is the second method.
In order for the first fiber of the fiber web 7 to exhibit elasticity, entanglement tends to proceed to an excessive extent, which is not preferable.

Table 1 shows one of the examples and a comparative example to be compared with the examples. In all cases, the nonwoven fabric contains 70% by weight of the EP-SH fiber as a first fiber and 30% by weight of rayon fiber as a second fiber. The ratio of the first fiber web to the second fiber web in the production of the nonwoven fabric was 50:50 in Examples and 50:50 to 10 in Comparative Examples.
0: 0. The first fiber web: the second fiber web =
100: 0 means a nonwoven fabric consisting of a uniform mixture of the first fiber and the second fiber. As a measure of the stretchability of the nonwoven fabric, the area shrinkage (%) of the laminated web of the first fiber web and the second fiber web after undergoing the heat treatment step is shown. The amount of shrinkage is 10 × 10c parallel to the web traveling direction
The calculation was based on the change in the size of the m section. The greater the amount of shrinkage, the greater the amount of elongation required to restore the nonwoven fabric to the dimensions of the original web, for example. It indirectly means that this nonwoven fabric is rich in elasticity. Disposable
As a surface material of a diaper, it is generally preferable that this area shrinkage is 40% or more. In the comparative example, the shrinkage amount has not reached 40%.

The nonwoven fabric according to the present invention obtained as described above can be used as a surface material of a disposable diaper so that the surface side, which is usually rich in water absorption, is brought into contact with the skin. The back layer side having many crimped fibers has an advantage that the back layer sides can be easily thermally welded to each other by ultrasonic welding or the like.

[0019]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a schematic process diagram showing an example of a manufacturing method according to the present invention.

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Nonwoven fabric 6 1st fiber web 7 2nd fiber web 21, 22, 23, 31, 41 Support body (conveyor) 33 High pressure fluid

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B68G 5/00 D04H 1/42 G D02G 3/24 X D04H 1/42 A41B 13/02 BE

Claims (2)

(57) [Claims] 1. A basis weight 20 obtained by mixing and entanglement of a hydrophobic fiber comprising an eccentric sheath-core or side-by-side type conjugate fiber which exhibits crimpability and elasticity and a hydrophilic fiber which exhibits substantially no elasticity. A stretchable non-woven fabric of about 250 g / m ² , wherein the non-woven fabric contains a relatively large amount of the hydrophilic fiber on one surface layer side, and has the hydrophobic property on the back layer side facing the surface layer side. Disposable diapers characterized in that they contain a relatively large number of conductive fibers and the fibers are entangled with each other without melting or interposition of a binder
The nonwoven fabric for a surface material of the above. ^2. A method for producing a stretchable nonwoven fabric having a basis weight of 20 to 250 g / m ² , wherein a fiber web is entangled with fibers under the action of jetting a high-pressure fluid, and then the web is heat-treated to develop fiber crimps. A first fiber of 30 to 70% by weight composed of an eccentric sheath-core or side-by-side type composite fiber which is crimped at a given temperature and exhibits elasticity, and a hydrophilic fiber which does not substantially exhibit elasticity. A first fiber web having a basis weight of 5 to 125 g / m ² obtained by mixing 2 to 30% by weight of two fibers; 90 to 100% by weight of the first fiber;
10% by weight and a second fiber web having a basis weight of 8 to 200 g / m ² on a support at a weight ratio of the first fiber web: second fiber web = 1: 3 to 3: 1. are laminated in placed, the high pressure fluid to act by spraying from the first fiber web side, said for surface materials of disposable diapers, characterized in that the expression of the crimp at a given temperature and thereafter Manufacturing method of nonwoven fabric.