JP3126510B2 - Super absorbent nonwoven material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nonwoven material containing fibers having a very high water absorption capacity.

[0002]

2. Description of the Related Art A water-absorbing polymer is becoming popular as a material for sanitary articles and the like. In recent years, a so-called polymer having a water absorbing capacity of several tens to several hundreds times its own weight has been further improved. Ultra superabsorbent polymers have also been developed. In this way, the ultra-high water-absorbing polymer, which has several hundred times its own water absorption capacity, can be used not only for conventional sanitary materials, but also for civil engineering, medical, agricultural and horticultural, food packaging, and new functions. Numerous application fields such as the material field are conceivable.

However, it is difficult to form the current superabsorbent polymer into a free shape, and it is often used in the form of granules or the like. For this reason, even if an application to a new application is considered as described above, there are many cases where the processing is an obstacle when actually trying to apply.

On the other hand, if the shape is fibrous, it is possible to use a highly water-absorbing polymer uniformly and by mixing it with other materials by using a weaving technique such as knitting or non-woven fabric, and the subsequent molding process is easy. Therefore, the shape of the material is convenient. However, superabsorbent polymers have extremely low strength,
When this is converted into a fiber, only a yarn that cannot withstand general use can be obtained by itself. For this reason, JP-A-58-3114
No. 9 discloses the use of a superabsorbent polymer and a strong polymer in combination using a composite spinning technique. However, the lower the ratio of the superabsorbent polymer, the lower the water absorbing ability, and this is an obstacle to the application to new uses.

[0005] Irrespective of the composite spinning technology, a method of producing a fabric by using a yarn consisting of a superabsorbent polymer alone with other fibers is disclosed in JP-A-3-97948 and JP-A-397948. Japanese Patent Application Laid-Open No. 45768/45 describes that a nonwoven fabric is formed in combination with a heat-fusible fiber, and Japanese Patent Application Laid-Open No. 2-80236 describes that a nonwoven fabric is formed in combination with a high crimp fiber.

[0006]

However, the prior art as described above has the following problems. That is, when a fiber having a water absorbing capacity several hundred times its own weight is used as the highly water-absorbing fiber, the fiber swells and its volume increases when water is absorbed. Moreover, such superabsorbent fibers generally have low strength.

For this reason, as disclosed in JP-A-3-97948 and JP-A-3-45769, the nonwoven fabric structure is reinforced by using heat-fused fibers. If the structure of the nonwoven fabric is fixed only by the fusion fibers, it becomes difficult to absorb the volume enlargement, and the water absorption cannot be actually increased.

In Japanese Patent Application Laid-Open No. 2-80236,
Instead of using the heat-fused fibers in the intermediate layer, instead of using the heat-fused fibers in the upper and lower layers, reinforcement is performed, and the intermediate layer is disclosed to be used in combination with a high crimped fiber to enhance cushioning properties.
Even if the middle layer can absorb the volume expansion of the high water-absorbing fiber, the upper and lower layers cannot absorb the volume expansion of the high water-absorbing fiber, so that the water absorption cannot be increased after all.

An object of the present invention is to solve such a problem, and an object of the present invention is to provide a nonwoven fabric material having extremely large water absorption performance and having sufficient strength as various material materials.

[0010]

According to the present invention, a water absorption amount of 10 g is provided.
/ G or more superabsorbent nonwoven fabric layer comprising a superabsorbent nonwoven fabric layer having an elongation of 50% or more is laminated and partially integrated on at least one surface of the superabsorbent nonwoven fabric material. It is.

The superabsorbent fiber used in the present invention is obtained by immersing a sample in a beaker containing 200 cc of 0.9% saline, leaving the sample to stand for 5 minutes, then taking out the sample and leaving it on a 10-mesh wire net for 1 minute. The water absorption determined by the difference from the weight before water absorption is extremely high at 10 g / g or more.
It has water absorption capacity of 0 times or more. In addition, for fiberization, it is preferable to perform spinning using the superabsorbent polymer alone, and it is difficult to maintain the water absorbing ability by using a composite spinning means or the like.

Examples of such superabsorbent fibers include, for example, those comprising a water-insoluble chain polymer containing an ester cross-link, for example, JP-A-63-159405 and JP-A-63-159440. There is one described in.

The fineness of the fiber is generally 1
The denier is preferably from 30 to 30 denier, and the staple having a fiber length of from 5 to 150 mm is desirably formed into a nonwoven fabric.

The water-absorbent nonwoven fabric layer of the present invention is composed of the above-mentioned superabsorbent fibers. The content of the superabsorbent fibers is preferably at most about 90% by weight from the viewpoint of strongness. The content is preferably about 10% by weight or more at which the effect is remarkable. Further, it is preferable to use a high-crimped fiber as described later in the water-absorbent nonwoven fabric layer because the water-absorbing performance is improved. Of course, the water-absorbent nonwoven fabric layer has another third
A component may be contained. The basis weight of the water-absorbing nonwoven fabric layer may be appropriately selected according to the use of the present invention.
の も の 250 g / m ² are easy to handle.

The nonwoven fabric material of the present invention is obtained by laminating the following stretchable nonwoven fabric layer on at least one surface of such a water-absorbent nonwoven fabric layer. The stretchable non-woven fabric layer is preferably a non-woven fabric having an elongation of 50% or more and having an elongation of 50% or more in both directions of the process.
cm or less is preferred.

Such a high elongation nonwoven fabric can be obtained by various methods, for example, International Publication WO 88/0938.
As described in Japanese Patent Laid-Open Publication No. H10-207, heat treatment is applied to a conjugate fiber formed by joining two kinds of components having different heat shrinkages in an eccentric shape such as side-by-side to obtain a high crimped fiber in which a spiral crimp is developed. The method used and the Japanese Patent Publication No. 1-30945
As described in Japanese Patent Application Publication No. JP-B 64-8746 and Japanese Patent Publication No. 64-8746, there is a method using a high elastic fiber such as a polyurethane elastic filament.

The present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the present nonwoven fabric using a high crimp fiber,
Reference numeral 1 denotes a superabsorbent fiber, and 2 denotes a heat-sealed fiber. The water-absorbent nonwoven fabric layer (A) has a network structure in which the crossing portions (3) of the fibers are fused by melting the heat-fused fibers.

As the heat-fusible fiber (2) to be mixed with the superabsorbent fiber (1), various known heat-fusible fibers can be used, and a high melting point component such as polyester or polyamide is used in the core, and polyethylene or polyamide is used in the sheath. A core-sheath composite spinning using a low melting point component such as a polymerized polyester is preferable, and 80 to 150
What can be fused at about ° C is mentioned.

The fineness of the heat-fused fiber (2) is preferably 1 to 30 denier, which is almost the same as that of the superabsorbent fiber.
It is recommended to use a staple of 100 mm. It is preferable that the heat-fusible fiber (2) is uniformly mixed with the superabsorbent fiber (1) in the range of 90 to 10% by weight.

The stretchable nonwoven fabric layer (B) uses the heat-fusible fiber (2) and the high crimped fiber (4). The high crimped fiber (4) includes polyethylene terephthalate and metal. Examples thereof include those bonded with a so-called cationic dyeable polyester obtained by copolymerizing a sulfonate group and the like.
Preferably, the denier is 20 and the fiber length is 30 to 100 mm.
Further, 10 to 90% by weight of the high crimped fiber (4) and 90 to 10% by weight of the heat fusible fiber (2) are uniformly mixed to obtain a basis weight of 1%.
It is preferable to form a nonwoven fabric of about 0 to 50 g / m ² ,
Such a raw material is heat-treated under a free tension to develop a spiral crimp to have an elongation of 50% or more.

Next, FIG. 2 is a cross-sectional view of the present nonwoven fabric using high elasticity fibers. The water-absorbent nonwoven fabric layer (A) is the same as FIG. Made of high elasticity fiber (5), polyisocyanate compound is added to thermoplastic polyurethane elastic body, spouted with high-speed air flow, deposited and collected in sheet form, and self-heat-bonded at the intersection. It is a non-woven fabric at least. In the case of such a non-woven fabric, the polyurethane elastic filament is 3
It is an ultrafine monofilament of 0 μm or less, and has a fine three-dimensional network structure. The basis weight of the nonwoven fabric is preferably about 20 to 100 g / m ² , although it depends on the use.
The stress at% elongation will be less than 500 g / cm.

The present nonwoven fabric material is such that the water-absorbent nonwoven fabric layer (A) and the stretchable nonwoven fabric layer (B) are laminated and partially integrated. As a method of partially integrating the water-absorbing nonwoven fabric layer (A) and the stretchable nonwoven fabric layer (B), a needling method, an embossing method, a bonding method, or the like can be employed. % Or less. Here, the bonding area is, for example, the design area of the embossed surface of the roll in the case of the embossing method, and is calculated in accordance with this in other bonding methods.

In FIG. 1, since the same heat-sealing fiber (2) is used for the water-absorbent nonwoven fabric layer (A) and the stretchable nonwoven fabric layer (B), the heat bonding fibers contained in both nonwoven fabric layers are used. (2)
The most efficient method is to integrate by fusing.
Therefore, heating and pressing may be performed with an embossing roll in which a polka dot pattern or the like is engraved. When a material such as urethane is used as shown in FIG. 2, it is possible to perform fusion using a high-frequency welding machine or the like.

Further, whether or not the superabsorbent fiber (1) is made to appear on the surface of the nonwoven fabric may be selected according to the use of the nonwoven fabric material, but the superabsorbent fiber (1) is not made to appear on the surface. For example, it is better to avoid the ordinary needle punching method. According to the above-mentioned heat fusion method, the superabsorbent fiber (1) can be seen on the surface of the nonwoven fabric material (the surface of the stretchable nonwoven fabric layer (B)). There is no.

The stretchable non-woven fabric layer (B) can maintain the strength of the non-woven fabric material if it is laminated on at least one surface of the water-absorbent non-woven fabric layer (A).
However, it is a matter of course that a sandwich structure may be used by using a stretchable nonwoven fabric layer (B) on both sides of the water-absorbent nonwoven fabric layer (A).

In any case, if the amount of the high water-absorbing fiber (1) used is 10% by weight or more based on the whole nonwoven fabric material, a material having a sufficient water absorbing ability will be obtained. still,
It is a matter of course that the nonwoven fabric material may be subjected to various post-processing such as dyeing, softening, flameproofing, and antibacterial.

[0027]

The nonwoven fabric material of the present invention comprises fibers having a very high water absorption. Such fibers are usually inferior in strength and difficult to form into a nonwoven fabric or the like, but in the present invention, the strength is maintained by forming a laminated structure with another nonwoven fabric.

Further, the high water-absorbing fiber swells greatly at the time of water absorption, and a desired amount of water absorption cannot be expected unless a space of such an enlarged volume is secured. By using a high material and partially integrating the nonwoven fabric, the nonwoven fabric elongates when absorbing water to form the space.

[0029]

【Example】

Examples 1 and 2 A copolymer containing sodium acrylate, acrylic acid, hydroxypropyl methacrylate, and methyl acrylate was spun according to the method described in JP-A-63-159440, and 8d, 51 mm high water-absorbing fiber staples. (B) was obtained. The strength of the super absorbent fiber staple is 1
g / d, elongation was 2.5%, and water absorption was 70 g / g.

Further, polyethylene terephthalate is used for the core,
Polyethylene terephthalate copolymerized with a 4d, 51 mm heat-bonded fiber staple (Belcombi 4080 manufactured by Kanebo) (b) composed of a conjugate fiber having a copolymer polyester (softening point 110 ° C.) disposed on a sheath and 5-sodium-sulfoisophthalic acid A 2.5d, 51 mm composite fiber staple (c) obtained by joining (intrinsic viscosity 0.529) and polyethylene terephthalate (intrinsic viscosity 0.634) side by side is mixed, and after carding, mixed with a cross wrapper. A web was prepared and subjected to preliminary light needle punching to obtain a water-absorbent nonwoven fabric.

On the other hand, the composite fiber staple (c) and the heat bonding fiber staple (b) were mixed to produce a mixed web in the same manner. Next, the two nonwoven fabrics were stacked and subjected to a dry heat treatment at 140 ° C. under free tension to fuse the heat-fused fibers. After the two nonwoven fabrics were integrated, embossing was performed at 130 ° C. to partially adhere. Table 1 shows the results.

[0032]

[Table 1]

Comparative Example 1 A nonwoven fabric was prepared in exactly the same manner as in Example 1 except that a mixed web of 2.5d, 51 mm staple made of polyethylene terephthalate and heat-bonded fiber staple (b) was used as the mixed web. The material was obtained. Table 1 shows the results. As is clear from the table, the nonwoven fabric material according to the present invention exhibits extremely large water absorption.

Example 3 The staples having high water absorption fiber of Example 1 (A) and the staples of heat-bonding fiber (Belcomi 4080 manufactured by Kanebo) (B) were used.
Water-absorbent nonwoven fabric was obtained in the same manner as in Example 1 by mixing cotton at a weight ratio of 0:20. On the other hand, a melt-blown non-woven fabric (Espansionone manufactured by Kanebo) having an elongation of 400% and a stress of 100 g / cm at the time of 100% elongation formed by self-bonding polyurethane elastic filaments, and the water-absorbing non-woven fabric are laminated. Partially bonded by a welding machine. Table 2 shows the results.

[0035]

[Table 2]

Comparative Example 2 A nonwoven fabric material was obtained in the same manner as in Example 2, except that the bonding was performed over the entire surface by a wet method.
Table 2 shows the results. As is clear from the table, the nonwoven fabric material according to the present invention exhibits extremely large water absorption.

[0037]

Industrial Applicability The present invention is a nonwoven material which is excellent in water absorbency and has no stickiness because the superabsorbent fiber does not appear on the surface and is excellent in safety, and is extremely useful for various uses. is there.

Examples of such uses include, but are not particularly limited to, water-absorbent mats, food trays, curing sheets, inoculum mats, waterproof tapes, and sweat-absorbing pads.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a nonwoven fabric material of the present invention using a high crimp fiber.

FIG. 2 is a cross-sectional view of the nonwoven fabric material of the present invention using a high elasticity fiber.

Claims (1)

(57) [Claims] 1. An elongation of at least 50% on at least one surface of a water-absorbent nonwoven fabric layer made of superabsorbent fibers having a water absorption of 10 g / g or more.
Highly water-absorbent nonwoven material characterized in that the above elastic nonwoven layer is laminated and partially integrated.