JP2001138425A - Waterproof/moisture permeable nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waterproof/moisture permeable nonwoven fabric excellent in moisture permeability, waterproofness, handling properties and strength. SOLUTION: A waterproof/moisture permeable nonwoven fabric (1) is constituted by integrally laminating an extremely fine fiber layer comprising extremely fine fibers with a mean fiber diameter of 0.1-5 μm and a synthetic long fiber layer comprising synthetic long fibers with a mean fiber diameter of 6-50 μm and the extremely fine fiber layer forming the nonwoven fabric has a dense structure wherein single fibers are mutually brought into close contact with other while holding a single fiber shape substantially and this nonwoven fabric has water pressure resistance of 4.9 kPa or more, water repellency of 50 or more and moisture permeability of 1,000 g/m2.24 hr or more. A waterproof/ moisture permeable nonwoven fabric (2) is constituted by interposing a sheetlike article having a softening point lower than that of synthetic long fibers between the extremely fine fiber layer and the synthetic long fiber layer. A waterproof/ moisture permeable nonwoven fabric (3) is constituted by further laminating the synthetic long fiber layer comprising synthetic long fibers with a mean fiber diameter of 6-50 μm on the extremely fine fiber layer of the integrally laminated nonwoven fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof / breathable nonwoven fabric, and more particularly to a waterproof / breathable nonwoven fabric useful for building materials, agricultural materials, civil engineering materials, packaging materials, etc., which require waterproofness and moisture permeability. About.

[0002]

2. Description of the Related Art In recent years, three-dimensional mesh fiber nonwoven fabrics having excellent moisture permeability and waterproofness have been widely used as building materials. For example, Japanese Unexamined Patent Publication (Kokai) No. 3-167362 discloses that an ultrafine fiber nonwoven fabric having an average fiber diameter of 8 μm or less and an average basis weight of 22 to 100 g / m ² has a fineness of about 1 to 15 denier and an average basis weight of 70 to 150 g / m ^{2 on} both sides. Laminated fiber non-woven fabric,
Agricultural sheets have been proposed that have strength and light-shielding properties as well as air permeability, moisture permeability and waterproofness. But,
Since the thickness of this sheet is large and its opacity is high, when this sheet is used as a building material, the back surface is not visible at the time of mounting work, so that the workability is poor. In addition, Japanese Unexamined Patent Publication
No. 216038 discloses an ultrafine fiber nonwoven fabric having a basis weight of 30 g / m ² or more and an average fiber diameter of 5 μm or less, and an average fiber diameter of 10 μm or less.
A moisture-permeable and waterproof sheet in which a 40 μm core-sheath type composite fiber nonwoven fabric is partially bonded and integrated has been proposed. However, since the laminated sheet is only partially adhered and integrated, it is inferior in strength, and there is a difference between the moisture-permeable effect and the waterproof effect at the joined and non-joined portions, and the effective moisture permeability and The current situation is that waterproofness cannot be obtained. As the improved product, a composite sheet of a microporous film and a nonwoven fabric has been proposed, but the microporous film is easily broken.
There were problems such as easy curling.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a waterproof / moisture permeable nonwoven fabric which is excellent in moisture permeability and waterproofness, and excellent in handleability and strength. is there.

[0004]

Means for Solving the Problems As a result of diligent studies on the above-mentioned problems, the present inventor has found that an ultrafine fiber layer having a specific fiber diameter and a synthetic long fiber layer are entirely laminated and integrated. The present inventors have found that the above-mentioned object can be achieved by maintaining a fine-grained structure in the ultrafine fiber layer, and have reached the present invention. That is, the invention claimed in the present application is as follows.

(1) A nonwoven fabric in which an ultrafine fiber layer having an average fiber diameter of 0.1 to 5 μm and a synthetic long fiber layer having an average fiber diameter of 6 to 50 μm are laminated and integrated over the entire surface. The fiber layer has a dense structure in which single fibers are closely adhered while substantially maintaining a single fiber shape, and the nonwoven fabric is
A waterproof / breathable nonwoven fabric having a water pressure resistance of 4.9 kPa or more, a water repellency of 50 or more, and a moisture permeability of 1000 g / m ² · 24 hr or more. (2) The waterproof / breathable material according to (1), wherein a sheet having a softening point lower than the softening point of the synthetic fiber is interposed between the ultrafine fiber layer and the synthetic fiber layer. Non-woven fabric. (3) The waterproof / moisture permeable nonwoven fabric according to (1), wherein a synthetic fiber long fiber layer having an average fiber diameter of 6 to 50 μm is further laminated on the ultrafine fiber layer of the laminated and integrated nonwoven fabric.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The waterproof / moisture permeable nonwoven fabric of the present invention has an average fiber diameter of 0.1 to 5 μm, preferably 0.5 to 5 μm.
It is a nonwoven fabric in which a 4 μm ultrafine fiber layer and a synthetic long fiber layer having an average fiber diameter of 6 to 50 μm, preferably 8 to 30 μm are laminated and integrated over the entire surface. The average fiber diameter of the ultrafine fiber layer is 0.1
If it is less than μm, the fiber layer is easily densified and the waterproof property is easily improved, but the air permeability and the moisture permeability are reduced, and the strength is also reduced. On the other hand, when the average fiber diameter exceeds 5 μm, air permeability and moisture permeability are improved, but it is difficult to make the fiber layer denser, and the waterproofness is reduced. When the average fiber diameter of the synthetic fibrous long fiber layer is less than 6 μm, the strength is insufficient, and when it exceeds 50 μm, the strength is improved, but the processability of lamination integration and waterproofness are reduced.

[0007] The ultrafine fiber layer may include one or two or more types of heat, such as a polyolefin resin such as polyethylene and polypropylene, a polyester resin, a polyamide resin, a polyurethane resin, a copolymerized polypropylene resin and a copolymerized polyester resin. Ultrafine fibers obtained by a melt blow method using a plastic resin are used, and can be obtained in the form of a nonwoven fabric. Among the ultrafine fibers, hydrophobic polyolefin-based ultrafine fibers are particularly preferable. The basis weight of the ultrafine fiber layer is preferably from 10 to 70 g / m ² , more preferably from 15 to 50 g / m ² .

[0008] The synthetic fibrous long fiber layer includes known synthetic fibrous long fibers, for example, polyolefin fibers such as polyethylene and polypropylene, polyester fibers, polyamide fibers, copolypropylene fibers, copolyester fibers, copolyamide fibers. And one or more types of long fibers such as conjugate fibers are used, and these can be obtained by forming a nonwoven fabric by a known spunbonding method, thermal bonding method, or the like. The synthetic fiber layer may be composed of the same fiber material and the same fiber diameter, or may be composed of two or more different fiber materials and different fiber diameters. Further, the cross section of the fiber is not limited to a round shape, but may be a flat shape, an irregular shape, or the like. The basis weight of the synthetic fiber long fiber layer is 20 to 100 g /
m ² is preferable, and more preferably 25 to 69 g / m ² .

The waterproof / moisture permeable nonwoven fabric according to the present invention is prepared by, for example, thermocompression bonding the entire surface of a two-layer laminated web of an ultrafine fiber layer and a synthetic long fiber layer, or laminating an ultrafine fiber nonwoven fabric and a synthetic long fiber nonwoven fabric. It is obtained by laminating and integrating the whole surface by thermocompression bonding. In the present invention, even when the single fibers are crushed by the thermocompression bonding, the ultrafine fiber layer adheres to the single fibers while keeping the shape of the single fibers substantially, and is thermocompression-bonded to form a dense structure. is necessary.
By making the ultrafine fiber layer a dense structure as described above,
Excellent waterproofness, moisture permeability and air permeability can be obtained.

In the thermocompression bonding described above, the entire surface of the lamination surface of the ultrafine fiber layer and the synthetic fiber layer is pressed evenly, and the ultrafine fibers adhere to the voids of the long fiber layer and are integrated so as to be buried, thereby forming a dense structure. And By having such a dense structure in which the thin fibers and the thick fibers are integrated, the thickness of the nonwoven fabric can be reduced, and excellent moisture permeability and water resistance can be obtained, and the strength can be improved. . For the thermocompression bonding, a known pair of smooth rolls, a felt calender, or the like can be used.The conditions of the thermocompression bonding are preferably appropriately selected depending on the constituent fiber material, fiber diameter, and the like. A temperature equal to or higher than the softening point and equal to or lower than the melting point, preferably a temperature obtained by adding 20 ° C. to the softening point, and set in a temperature range obtained by subtracting 20 ° C. from the melting point (for example, 80 to 240 ° C.), and the pressure is 5 to 100 kg. / Cm ² . The thermocompression bonding can be performed using one or a combination of two or more of a pair of smooth rolls (for example, a metal roll and a resin roll, a metal roll and a rubber roll, a metal roll and a paper roll, a pair of metal rolls, etc.) and a fercalender. it can.

Further, the waterproof and moisture-permeable nonwoven fabric of the present invention
The water pressure resistance is 4.9 kPa (500 mmH_TwoO) above
Or 6.86 to 19.6 kPa (700 to 2000 m
mH _TwoO) and the water repellency is 50 or more, preferably 70
~ 100. Unless the water pressure of the non-woven fabric is less than 4.9 kPa
Or, if the water repellency is less than 50, it can withstand the outdoor environment.
Does not provide sufficient waterproofing when exposed to the elements
No. The moisture permeability of the waterproof / breathable nonwoven fabric is 1000 g / m
^Two24 hours or more, preferably 2000 to 7000 g /
m^Two・ 24 hours. 1000 g / m moisture permeability^Two・ 2
If it is less than 4 hours, dew condensation tends to occur in an indoor environment.
The waterproof / breathable nonwoven fabric according to the present invention has a point of preventing dew condensation.
Has excellent air permeability, for example, Gurley type
It is preferable that the temper is 50 seconds or less.

In the present invention, the weight of the waterproof / moisture permeable nonwoven fabric is preferably 30 to 150 g / m ² , and preferably 50 to 120 g / m ^2.
2 is more preferable, and the average apparent density is 0.2 to 0.1.
9 g / m ³ is preferable, and more preferably 0.3 to 0.8.
g / m ³ . The waterproof / moisture permeable nonwoven fabric can have a three-layer structure from the viewpoint of improving processability such as curl properties and mechanical properties such as strength. As such a nonwoven fabric having a three-layer structure, for example, a waterproof / breathable nonwoven fabric in which a sheet having a softening point lower than the softening point of the synthetic fiber is interposed between the microfiber layer and the synthetic fiber layer Or, a waterproof / moisture permeable nonwoven fabric obtained by further laminating a synthetic fiber long fiber layer having an average fiber diameter of 6 to 50 μm, preferably 8 to 30 μm on an ultrafine fiber layer of a nonwoven fabric obtained by laminating and integrating a microfine fiber layer and a synthetic fiber long fiber layer. No.

The sheet is not particularly limited as long as it has a softening point lower than the softening point of the synthetic fiber. Preferably, it has a softening point 20 ° C. or more lower than the softening point of the synthetic fiber. As such a sheet-like material, for example, polyethylene, polypropylene, polyolefin-based fibers such as copolymerized polypropylene, a sheath made of polyethylene and a core made of polyethylene terephthalate has a low softening point, and the core has a high softening point. Nonwoven fabrics composed of core-sheath type composite fibers, side-by-side type composite fibers, etc., tape yarn cloths, nets, perforated films and the like can be mentioned. The basis weight of the sheet is 10 to 100 g.
/ M ² is preferable, and more preferably 15 to 70 g / m ²
It is. The thickness is preferably from 0.01 to 1.0 mm, and more preferably from 0.01 to 0.5 mm.

According to the waterproof / moisture permeable nonwoven fabric of the present invention, an ultrafine fiber layer having a specific average fiber diameter and a synthetic long fiber layer are laminated and integrated on the entire surface, and the ultrafine fiber layer is composed of a single fiber By forming a dense structure while substantially maintaining the shape of the nonwoven fabric, the thickness of the nonwoven fabric can be reduced, the average apparent density of the fibers can be increased, and excellent waterproofness, moisture permeability and air permeability can be obtained. And the strength can be improved.

[0015]

The present invention will be described in more detail with reference to the following examples. In addition, each physical property in an example was measured by the following method. (1) Moisture permeability: JIS-L-1099 (40 ° C, RH90
(2) Waterproofness: JIS-L-1092 A method (water pressure resistance) and water repellency test (Spey test) (3) Air permeability: JIS-L-1096 B method (Gurley type) (4) Tensile strength : JIS-L-1096 (5) Tear strength: JIS-L-1096 D method (Pendulum method) (6) Apparent density: JIS-L-1096 Determined from basis weight and thickness. (7) Average fiber diameter: Take a 500x enlarged photograph with a microscope,
The values are shown as an average value of 10 pieces.

Example 1 A unit weight of 40 g / m ² obtained by a known spunbonding method
Polypropylene long-fiber nonwoven fabric (average fiber diameter 23 μm,
(Melting point: 173 ° C.)
^2. Polypropylene ultrafine fiber nonwoven fabric (average fiber diameter 1.7
μm, melting point 168 ° C.) and a pair of thermocompression rolls (combination of metal roll and paper roll, processing conditions: metal roll surface temperature 140 ° C., pressure 30 kg / cm ² , speed 20 m / min, microfiber nonwoven fabric and metal Roll contact)
Then, a nonwoven fabric laminated and integrated by heating and pressing was obtained. The obtained nonwoven fabric has a water pressure resistance of 14.7 kPa (1500 mmH
₂ O), water-repellent 100, moisture permeability 5200g / m ² · 24
hr, air permeability 2.5 sec / 100cc, tensile strength longitudinal direction 1
27N / 5cm, transverse direction 39N / 5cm, tear strength longitudinal direction 3.9N, transverse direction 4.9N, and had high waterproofness and moisture permeability and excellent mechanical strength. In addition, the average apparent density of the nonwoven fabric was 0.65 g / cm ³ , and it was confirmed that the ultrafine fiber nonwoven fabric was closely adhered while substantially maintaining the single-fiber shape, and had a dense structure by lamination and integration over the entire surface. Was.

Example 2 A nonwoven polyester long-fiber nonwoven fabric having a basis weight of 30 g / m ^{2 and} an average fiber diameter of 26 μm and a melting point of 26
0 ° C), and a sheath weight of 30 g / m by a spun bond method comprising a sheath made of polyethylene and a core made of polyethylene terephthalate.
² composite fiber non-woven fabric (average fiber diameter 16 μm, melting point 120
C. (sheath), 255 ° C. (core)) and a nonwoven polypropylene microfiber nonwoven fabric (average fiber diameter: 1.7 μm, melting point: 168 ° C.) with a basis weight of 30 g / m ² obtained by a melt blow method. Thermocompression bonding roll (combination of metal roll and resin roll, processing conditions: metal roll surface temperature 150)
At a temperature of 15 ° C., a pressure of 15 kg / cm ² , a speed of 20 m / min, and contact of the microfiber nonwoven fabric with the metal roll) to obtain a three-layer nonwoven fabric laminated and integrated by heating and pressing. The obtained nonwoven fabric has a water pressure resistance of 10.78 kPa (1100 mmH ₂ O),
Water repellency 100, moisture permeability 4100 g / m ² · 24 hr, air permeability 8.5 sec / 100 cc, tensile strength 176 N /
5cm, transverse direction 98N / 5cm, tensile strength longitudinal direction 7.8
N, 11.8 N in the horizontal direction, high water resistance and moisture permeability, and excellent mechanical strength. In addition, the average apparent density was 0.58 g / cm ³ , and it was confirmed that the ultrafine fiber nonwoven fabric was closely adhered to the entire surface by lamination and integration while substantially maintaining the single fiber shape, and had a dense structure.

[0018]

The waterproof / moisture permeable nonwoven fabric of the present invention has high water repellency and high water resistance, is excellent in waterproofness, air permeability and moisture permeability, has excellent mechanical properties, and further has good handleability. Since it is excellent, it can be suitably used as a waterproof base material such as a house wrap, a building material, a filter material, an agricultural material, a civil engineering material, a packaging material, and the like.

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Claims (3)

[Claims] 1. A nonwoven fabric in which an ultrafine fiber layer having an average fiber diameter of 0.1 to 5 μm and a synthetic long fiber layer having an average fiber diameter of 6 to 50 μm are laminated and integrated on the entire surface, and the ultrafine fiber forming the nonwoven fabric is provided. The layer has a dense structure in which single fibers are adhered to each other while substantially maintaining the single fiber shape, and the nonwoven fabric has a water pressure resistance of 4.9 kPa or more, a water repellency of 50 or more, and a moisture permeability of 1 or more.
A waterproof / moisture permeable nonwoven fabric having a weight of 000 g / m ² · 24 hr or more. 2. The waterproofing device according to claim 1, wherein a sheet-like material having a softening point lower than the softening point of the synthetic fiber is interposed between the ultrafine fiber layer and the synthetic fiber layer. Moisture permeable nonwoven fabric. 3. The waterproof / moisture permeable nonwoven fabric according to claim 1, wherein a synthetic fiber long fiber layer having an average fiber diameter of 6 to 50 μm is further laminated on the ultrafine fiber layer of the laminated and integrated nonwoven fabric.