JP2000234253A - Bulky nonwoven fabric, its production and wiping material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bulky nonwoven fabric capable of corresponding to various uses, having many ridge-like parts on the surface and excellent in design and functionality, and further to provide an inexpensive wiping material capable of highly wiping off various dirt attached to an object. SOLUTION: This bulky nonwoven fabric is obtained by jetting a high- pressure water-current on a fiber web obtained by laminating the second fiber layer substantially not heat-shrinkable at the temperature at which the first fiber layer is heat-shrunk, at least on one surface of the first fiber layer having heat-shrinkable properties, at <=1.5 mm interval to interlace the web previously, placing the previously interlaced web on a supporter for forming opening, jetting the high-pressure water current to the web at 2-15 mm interval in a stripe shape in the direction crossing to the longitudinal direction to form opening parts arranged in the stripe shape, subjecting the web with the opening parts to a heating treatment to provide the objective bulky nonwoven fabric having stripe-shaped low density region 3 and ridge-like parts 2 extending in the longitudinal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bulky nonwoven fabric having a large number of ridges on its surface and excellent in design and functionality, and is used for dry wipers, wet wipers, and water around kitchens and bathrooms. The present invention is useful for a wiping material such as a cleaning wiper, a packaging material, a female material of a hook-and-loop fastener, and particularly relates to a wiping material using a bulky nonwoven fabric.

[0002]

2. Description of the Related Art Conventionally, there have been proposed various bulky nonwoven fabrics in which two or more fiber layers having different heat shrinkage rates are laminated and one fiber layer is thermally shrunk to form irregularities in the other fiber layer. Have been. For example, JP-A-60-17164 discloses a nonwoven fabric obtained by laminating a long-fiber nonwoven fabric and a non-woven fabric having a large heat shrinkability and forming a ridge on the surface of the long-fiber nonwoven fabric, and JP-A-63-309657. Discloses a nonwoven fabric comprising a heat-shrinkable fiber and a non-shrinkable fiber, in which the non-shrinkable fiber bends due to the shrinkage of the heat-shrinkable fiber, and a large number of ridges are formed on the surface of the nonwoven fabric. Also, the present applicant has proposed a nonwoven fabric in which streaky entangled portions and a large number of ridge-shaped convex portions are formed in portions other than the entangled portions as disclosed in JP-A-9-158022.

[0003]

However, these nonwoven fabrics have the following problems. JP-A-60-171
No. 64 and Japanese Unexamined Patent Publication (KOKAI) Showa No. 63-309657, both of which have two fiber layers integrated by fiber entanglement treatment by needle punching or high pressure columnar water flow, and then heat shrinkage stress of one fiber layer is increased. The other fiber layer is made to "swell" by utilizing the ridges, and the ridges formed by the swelling of the fiber layer are randomly formed on the entire nonwoven fabric. When these are used as cleaning materials, fine dust and dirt are collected in the ridges or in the space between the ridges, but relatively large debris such as bread crumbs are sufficiently collected. And damage the object to be wiped.

In the non-woven fabric disclosed in Japanese Patent Application Laid-Open No. 9-158022, a ridge-shaped convex portion is formed in a streak-like entangled portion and a portion other than the entangled portion. However, since the high-density region is formed in the streak-like entangled portion, dirt is easily clogged in the streak-like entangled portion, and the life as a cleaning material is short. The present invention has been made to solve such a problem, and an object of the present invention is to provide a bulky nonwoven fabric having excellent design and functionality having a large number of ridges on a surface that can be used for various applications. It is still another object of the present invention to provide an inexpensive and highly wiping material for wiping various dirt attached to an object.

[0005]

In order to achieve the above object, the bulky nonwoven fabric of the present invention is a nonwoven fabric in which a first fiber layer and a second fiber layer are integrated by entanglement of fibers, and has a width of 3 mm. The following low-density streaks extend in the longitudinal direction at intervals of 2 to 15 mm, and ridges are present between the streaks of the second fiber layer. By adopting such a configuration, a nonwoven fabric having excellent design properties and functionality capable of responding to various uses can be obtained.

[0006] It is desirable that three or more ridges exist between the streaks of the second fiber layer of the bulky nonwoven fabric of the present invention per 1 cm in the longitudinal direction.

[0007] The streaky low-density region in the bulky nonwoven fabric of the present invention is desirably formed by an opening.

The first fibrous layer in the bulky nonwoven fabric of the present invention is a fibrous layer containing at least 30% by weight of a heat-shrinkable fiber having a maximum heat shrinkage of at least 50%.
This is desirable in that many ridges can be obtained in the second fiber layer. Further, it is desirable that the second fiber layer is a fiber layer which does not substantially thermally shrink at the temperature at which the first fiber layer thermally shrinks, since a ridge-like object can be easily obtained.

[0009] The bulky nonwoven fabric of the present invention is characterized in that the first fibrous layer having the property of being thermally contracted by heat is provided on at least one surface of the first fiber layer.
A second material that does not substantially thermally shrink at a temperature at which the fiber layer thermally shrinks;
A fiber layer is laminated, a pre-entangled web preliminarily entangled by spraying a high-pressure water stream at an interval of 1.5 mm or less onto this is placed on a support for forming an opening, and is placed in a direction orthogonal to the longitudinal direction. Two
A high-pressure water stream is sprayed at intervals of 15 mm to form streaked aligned openings, and then heat-treated to thermally shrink the first fibrous layer, thereby causing the second fiber between the streaks. It can be manufactured by forming a ridge on the fiber layer.

By using the bulky nonwoven fabric of the present invention as a wiping material, various kinds of dirt attached to an object can be wiped off at a high cost at a low cost. Less than,
The contents of the present invention will be described.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The bulky nonwoven fabric of the present invention is a nonwoven fabric in which a first fiber layer and a second fiber layer are integrated by entanglement of fibers. The structure extends in the longitudinal direction at an interval of 2 to 15 mm, and a ridge exists between the streaks of the second fiber layer. One example of the form of the bulky nonwoven fabric of the present invention is shown in FIG. The streak-like low-density region having a width of 3 mm or less here refers to a row in which the number of constituent fibers is clearly smaller than that of the ridges formed in the second fiber layer. In addition, the longitudinal direction refers to the machine arrangement direction in the nonwoven fabric manufacturing process. This is shown in FIG. 2 and FIG.
Compared with the conventional nonwoven fabric having a large number of ridges on the surface, the nonwoven fabric of FIG. 2 has the ridges formed at random over the entire nonwoven fabric, and the nonwoven fabric of FIG. The nonwoven fabric has a region and is clearly different in design from the bulky nonwoven fabric of the present invention.

[0012] In the bulky nonwoven fabric of the present invention, the width of the streak-like low-density region is preferably 3 mm or less, more preferably 1-2 mm. If the width of the low-density region exceeds 3 mm, the ratio of the streaks becomes too large, and the effect of the ridges is not sufficiently exhibited. The interval between the streak-like low-density regions is preferably 2 to 15 mm. More preferably, the distance is 3 to 7 mm. If the interval is less than 2 mm, the surface area occupied by the ridges is too small, and if it exceeds 15 mm, there is not much difference from the conventional nonwoven fabric in which ridges are formed on the entire nonwoven fabric.

It is preferable that there are three or more ridges between the stripes per cm in the longitudinal direction. More preferably, the number is 5 to 8 per 1 cm in the longitudinal direction. If the number of ridges is less than 3, fine dust cannot be sufficiently collected by the ridges when used as a wiping material.

Preferred examples of the fibers constituting the first fiber layer of the present invention include heat-shrinkable fibers that shrink by heat. In the present invention, it is preferable to use a heat-shrinkable fiber having a maximum heat shrinkage of at least 50%. Here, the maximum heat shrinkage refers to the largest heat shrinkage of the heated fiber while maintaining the shape of the fiber. When the maximum heat shrinkage is less than 50%, the heat shrinkage of the first fiber layer is insufficient and the number of ridges formed on the second fiber layer is reduced, resulting in poor bulkiness.

In the present invention, the maximum heat shrinkage is at least 5
0% heat shrinkable fiber, melting peak temperature Tm
It is preferable to use a fiber made of a resin containing 70% by weight or more of an ethylene-propylene random copolymer having (C) in the range of 130 <Tm <145. Here, the melting peak temperature refers to the temperature at which the DSC curve shows the highest value when the heat of fusion of the resin is measured by a differential scanning calorimeter (DSC). If the melting peak temperature is lower than 130 ° C., the resin will exhibit rubber-like elasticity, and the fiber will have poor card permeability. On the other hand, if the temperature exceeds 145 ° C., the heat shrinkage of the fiber becomes about the same as ordinary polypropylene, which is not preferable.

Further, as the fiber whose apparent fiber length is shortened by heat, besides heat-shrinkable fiber, latent crimpable fiber which develops three-dimensional crimp by heat can also be used.
In the present invention, it is preferable to use a fiber that exhibits 25 or more three-dimensional crimps per 25 mm by heating.
If the number is less than 25, the entire fiber layer cannot be sufficiently shrunk. Preferably, the number is 30 to 60. When such latently crimpable fibers are used, the first fiber layer after heat shrinkage has elasticity, so that the finally obtained nonwoven fabric has elasticity.

The heat-shrinkable fiber or latently crimpable fiber is
It is preferable that the first fiber layer contains 30% by weight or more. If the amount is less than 30% by weight, the shrinkage of the first fiber layer is insufficient. If these fibers are contained in an amount of 30% by weight or more, other fibers can be mixed in the first fiber layer. Fibers to be mixed are not particularly limited, and recycled fibers such as rayon, semi-synthetic fibers such as acetate, acrylic fibers, polyamide fibers such as nylon 6, nylon 66,
One or more selected from polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, and polyolefin fibers such as polyethylene and polypropylene can be used. In particular, when using a hydrophobic fiber such as a fiber made of the above-mentioned ethylene-propylene random copolymer, when the first fiber layer is formed by mixing with a rayon fiber which is a hydrophilic fiber,
This is preferable because the formation failure due to the impact of the high-pressure water flow is suppressed, and the entanglement of the fibers by the high-pressure water flow becomes strong. Of course, the first fiber layer may be composed of only heat shrinkable fibers or latently crimpable fibers.

The form of the first fiber layer may be a card web such as a parallel web made of staple fibers, a cross web, a semi-random web, a random web, a wet papermaking web or an air-laid web made of short fibers having a fiber length of 25 mm or less. Any of a spunbonded nonwoven fabric made of long fibers and a melt-blown nonwoven fabric may be used. However, considering workability, the first fiber layer is preferably a card web made of staple fibers. The basis weight of the first fiber layer is preferably 10 to 30 g / m ² . If it is less than 10 g / m ^2, it is difficult to form a uniform fibrous web, and if it exceeds 30 g / m ² , the shrinkage rate does not change.

Next, the second fiber layer will be described. Second
The fiber layer forms a large number of ridges by heat shrinkage of the first fiber layer. Therefore, the material constituting the second fiber layer is not particularly limited as long as it does not substantially shrink at the temperature at which the first fiber layer thermally shrinks.
For example, recycled fibers such as rayon, semi-synthetic fibers such as acetate, acrylic fibers, polyamide fibers such as nylon 6, nylon 66, polyester fibers such as polyethylene terephthalate and polybutylene terephthalate, and polyolefin fibers such as polyethylene and polypropylene. One or two or more can be arbitrarily selected from among them. The fiber shape and the like are not particularly limited, and conjugate fibers and fibers having an irregular cross section can be used arbitrarily.

When the bulky nonwoven fabric of the present invention is used as a wet wiper such as a wet tissue or a towel, the second fiber layer may be composed mainly of hydrophilic fibers. Among them, rayon fiber is preferably used because it is rich in water absorption and staple fibers of a certain length are easily available. When used as a cleaning wiper around water in a kitchen or bathroom, it is preferable that the second fiber layer is composed of 20% by weight or more of hydrophilic fiber or acrylic fiber. Further, when used as a dry wiper, the ratio of hydrophobic fibers such as polyester may be appropriately changed.

The form of the second fiber layer is not particularly limited either. For example, a card web such as a parallel web made of staple fibers, a cross web, a semi-random web or a random web, or a wet papermaking web made of short fibers having a fiber length of 25 mm or less. And air-laid webs, spunbonded nonwoven fabrics made of long fibers, and melt-blown nonwoven fabrics. The basis weight of the second fiber layer may be appropriately determined depending on the application, but is preferably 10 to 60 g / m ² in consideration of the confounding property in the high-pressure water jet method described later.

The first fiber layer and the second fiber layer are integrated by entanglement of the fibers. As a method of integrating by confounding, a needle punch method, a high-pressure water jet method, or the like can be used. In the present invention, the pore size is 0.05 to 0.1.
A preferred method is to inject a high-pressure water stream from a nozzle having 5 mm orifices formed at regular intervals in a direction perpendicular to the longitudinal direction. At this time, in order to improve the entanglement strength between the fibers, it is preferable to form a preliminary entangled web by jetting a high-pressure water stream at an interval of 1.5 mm or less and preliminary entanglement.
The water pressure at this time is preferably 1 to 6 MPa.
If the water pressure is less than 1 MPa, the entanglement of the fibers cannot be said to be sufficient, and the surface of the non-woven fabric becomes fuzzy. Water pressure is 6MP
If the value exceeds a, the fibers are greatly entangled with each other and become a dense nonwoven fabric, and when used as a wiping material, a sufficient space for collecting dust cannot be obtained.

Next, the pre-entangled web is placed on a support for forming holes, and the web is placed in a direction perpendicular to the longitudinal direction.
A high-pressure water stream is jetted at intervals of mm to form streaks and aligned apertures. In the present invention, the interval between the streak-like low-density regions is adjusted to a predetermined interval based on the interval between the orifices and the shrinkage rate in the width direction during the heat shrinking process. The water pressure at this time is preferably 3 to 6 MPa.
If the water pressure is less than 3 MPa, clear pores cannot be obtained, and a low-density region is hardly formed. On the other hand, if the water pressure exceeds 6 MPa, the formation tends to be disordered, the number of fibers in the low-density region is too small, and the strength of the nonwoven fabric is significantly reduced.

Examples of the support for forming openings include a pattern net formed by weaving monofilaments and metal wires, and a roll provided with protrusions. The obtained aperture shape is not particularly limited, and may be any of a circle, an ellipse, a rhombus, a rectangle, and the like. The opening pattern is formed in a staggered shape, a lattice shape, or the like, in which the openings are arranged in one row or two rows in the longitudinal direction, or a mixture thereof. The opening has a hole diameter of 0.5.
What is necessary is just 3 mm. If the pore diameter exceeds 3 mm, the trapping effect when used as a wiping material is insufficient, and if it is less than 0.5 mm, the pores disappear after heat treatment, and a low-density region is not formed. .

Subsequently, the integrated laminated nonwoven fabric is subjected to a heat treatment at a temperature at which the heat-shrinkable fibers in the first fiber layer shrink, so that the first fiber layer is shrunk and the second fiber layer between the streaks is formed. To form a ridge. On the other hand, the openings arranged in the longitudinal direction are deformed in a random direction by the contraction action,
The width also becomes narrow in accordance with the contraction to form a streak-like low-density region. The method of the heat treatment is not particularly limited. For example, the heat treatment may be performed using a hot air penetration dryer, a pin tenter, or the like while the nonwoven fabric is over-fed. At this time, the number of ridges per 1 cm in the longitudinal direction of the nonwoven fabric can be easily adjusted by the overfeed ratio (the inlet speed of the processing machine × 100 / the outlet speed of the processing machine). For example, when the overfeed rate is increased, the number of obtained ridges increases, and the overfeed rate is preferably 80% or more, and more preferably 100 to 140%. Further, the width of the streak-like low-density region can be easily adjusted by controlling the width by a pin tenter or the like, heat treatment temperature, heat treatment speed, and the like.

The bulky nonwoven fabric thus obtained is
It is particularly effective when used as a cleaning material such as a dry wiper, a wet wiper, and a wiper for washing water around a kitchen or a bathroom.For example, when used as a dry wiper, small debris such as dust and dust are mainly ridge-shaped. The relatively large debris such as bread crumbs can be collected in the streak-like low density area, resulting in a long-life wiper. At this time, a surfactant such as liquid paraffin may be attached. When used as a wet wiper, the use of hydrophilic fibers as the main component is effective and rich in wettability, and a large amount of dirt can be collected and held in a streak-like low-density region.

When used as a wiper for washing around water, it is preferable to use mainly acrylic fibers which are excellent in hydrophilicity and lipophilicity. Fineness is 0.3 ~
3 dtex is preferred in terms of the surface area of the fiber and the rigidity of the fiber. In addition, on the surface of the fiber, acrylic fibers with streaks having a large number of groove recesses in the length direction are excellent in the effect of scraping dirt off the cleaning surface and adsorbing, 5 μm length per 10 μm perimeter of fiber
It is preferable that there are three or more of the above nonwoven fabrics for cleaning. Such an acrylic fiber is, for example, Toleron T
733 (trade name, manufactured by Toray Industries, Inc.). The obtained cleaning wiper can collect a large amount of dirt mainly in a streak-like low-density region, and can collect a part of small dirt with a ridge. Further, even when used in combination with a detergent, the streak-like low-density region contributes to the foaming property of the detergent, and the object can be washed smoothly.

Further, the bulky nonwoven fabric of the present invention can be used as a wrapping material, a female material of a hook-and-loop fastener and the like in addition to the wiping material.

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be specifically described with reference to embodiments. In addition, the thickness of the obtained nonwoven fabric and the wiping property (collection rate, retention rate) when dry were measured by the following methods, respectively.

[Thickness] Thickness measuring machine (trade name: THICKNESS
GAUGE model CR-60A manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd.)
The measurement was performed with a load of 3 g / cm ² applied to the obtained nonwoven fabric.

[Wipeability] Collection rate: Spread 0.5 g of bread crumbs uniformly on a glass surface, and apply it to a flooring cleaning tool manufactured by Kao Corporation (wiping area 10 cm × 26 cm, handle length 34 cm, weight 235 g). Attach a non-woven fabric whose weight has been measured in advance, and place 5
The weight of the nonwoven fabric after one reciprocation was measured after moving a distance of 60 cm with a load of 00 g placed thereon, and the difference in weight before and after wiping was defined as the collected amount (g). And the amount collected /
The collection rate (%) was obtained by multiplying 0.5 by 100. Retention rate: The cleaning tool collected above was dropped five times from a height of about 10 cm, and the weight difference between the weight of the nonwoven fabric after falling five times and the weight of the nonwoven fabric before wiping was defined as the retention amount. Then, the value obtained by multiplying the retained amount / collected amount by 100 was defined as the retention ratio (%).

Example 1 The first fiber layer was made of an ethylene-propylene random copolymer having a melting peak temperature (Tm) of 138 ° C. and a maximum heat shrinkage of 150 ° C. at 92 ° C.
%, Fineness of 2.2 dtex, and a heat-shrinkable fiber having a fiber length of 51 mm were formed into a card web having a basis weight of 10 g / m ² using a parallel card. As the second fiber layer, fineness is 1.7 dtex, fiber length is 40 mm
60% by weight of polyethylene terephthalate fiber of 40% by weight rayon fiber, 1.7dtex fineness and 51mm fiber length
And a web having a basis weight of 20 g / m ² was prepared using a parallel card and laminated on the first fiber layer.

Next, a high-pressure columnar water stream having a water pressure of 3 MPa was jetted from a nozzle provided with orifices having a hole diameter of 0.12 mm at intervals of 0.6 mm onto a 90-mesh support onto the second fiber layer side of the laminated web, The fibers were pre-entangled to form a pre-entangled web. Next, on a support for forming an opening (25-mesh plain woven fabric manufactured by Japan Filcon Co., Ltd.), a high-pressure columnar structure with a water pressure of 4 MPa was provided on the first fiber layer side from a nozzle having orifices having a hole diameter of 0.15 mm at intervals of 7 mm. A water flow was jetted to obtain a nonwoven fabric in which one row and two rows of apertures were formed in a streak shape in the longitudinal direction.

Using a pin tenter, the obtained non-woven fabric was
30 ° C., overfeed rate 130%, width shrinkage rate {(inlet width−outlet width) × 100 / inlet width} = 20% and 3
Heat treatment is performed for 0 seconds to shrink the heat-shrinkable fiber, and FIG.
A bulky nonwoven fabric as described above was obtained.

[Example 2] A pre-entangled web was formed into a support for forming holes (25-mesh plain fabric manufactured by Nippon Filcon Co., Ltd.).
On the first fiber layer side, there are three orifices with a hole diameter of 0.15 mm.
A bulky nonwoven fabric was obtained in the same manner as in Example 1, except that a high-pressure columnar water stream having a water pressure of 3 MPa was jetted from nozzles provided at mm intervals.

Example 3 Overfeed rate was 80%
A bulky nonwoven fabric was obtained in the same manner as in Example 1 except that the above conditions were satisfied.

Example 4 As the second fiber layer, a fineness of 1.
A bulky nonwoven fabric was obtained in the same manner as in Example 1, except that acrylic fibers (Trelon T733, manufactured by Toray Industries, Inc.) having a fiber length of 5 dtex and a fiber length of 38 mm were used.

[Comparative Example 1] The laminated web of Example 1
On a 0-mesh support, a high-pressure columnar water stream with a water pressure of 4 MPa is jetted from a nozzle provided with orifices having a hole diameter of 0.13 mm at intervals of 1 mm on a 0-mesh support. Width shrinkage 20
% For 30 seconds to shrink the heat-shrinkable fibers to obtain the nonwoven fabric shown in FIG.

[Comparative Example 2] A pre-entangled web was sprayed onto a first fiber layer side of a 90-mesh support by a high-pressure columnar water stream having a water pressure of 4 MPa from a nozzle provided with orifices having a hole diameter of 0.15 mm at intervals of 7 mm. Except for the above, a nonwoven fabric shown in FIG. 3 was obtained in the same manner as in Example 1.

Table 1 shows the performances of Examples 1 to 4 and Comparative Examples 1 and 2.

[0041]

[Table 1]

When the bulky nonwoven fabrics of Examples 1 to 3 were used as a dry wiper, the bread crumbs were considerably adhered to the streak-like low-density area, and the wiping property was light and good. This bulky nonwoven fabric was immersed in water, lightly squeezed, drained, and wiped with a dirty hand as a wet wiper. The bulky nonwoven fabric of Example 4 was soaked in water, lightly squeezed, drained, and wiped with a cup.
The tea astringency in the cup was easily wiped off. On the other hand, the nonwoven fabrics of Comparative Examples 1 and 2 all had a large amount of unwiped residue, and the wiping properties were not good.

[0043]

According to the bulky nonwoven fabric of the present invention, streaky low-density regions having a width of 3 mm or less extend in the longitudinal direction at intervals of 2 to 15 mm, and ridges between the streaks in the second fiber layer. The presence of a nonwoven fabric makes the nonwoven fabric excellent in design and functionality, and can cope with various uses that cannot be achieved by conventional nonwoven fabrics.

In particular, when used as a wiping material, streak-like low-density areas selectively collect relatively large debris, and fine debris is captured by a large number of ridges of 3 or more per cm in the longitudinal direction. It can be collected and used as a wiping material in all fields.

[Brief description of the drawings]

FIG. 1 shows a perspective view of a bulky nonwoven fabric of the present invention.

FIG. 2 is a perspective view of a conventional nonwoven fabric having many ridges on its surface.

FIG. 3 shows a perspective view of another conventional nonwoven fabric having a large number of ridges on its surface.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bulk nonwoven fabric 2 Ridge material 3 Low density area 4 High density area

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // A44B 18/00 A44B 18/00 F term (Reference) 3B074 AA02 AA08 AB01 AC02 AC03 3B100 DA00 4F100 AJ05B AK42B AK64A AL03A BA02 BA10A BA10B BA13 DC11A DC11B DD04B DD05A DD05B DG15A DG15B DG18B EC051 EC092 EJ422 GB15 GB71 GB90 JA03A JA03B JA13A JA13B JA15 YY00A YY00B 4L047 AA12 AA17 AA21 AB02 AB10 BA04 BD01

Claims (7)

[Claims] 1. A nonwoven fabric in which a first fiber layer and a second fiber layer are integrated by entanglement of fibers, wherein streaky low-density regions having a width of 3 mm or less extend in the longitudinal direction at intervals of 2 to 15 mm. A bulky nonwoven fabric characterized by having ridges between the streaks of the second fiber layer. 2. The ridge between the streaks of the second fiber layer,
The bulky nonwoven fabric according to claim 1, wherein three or more pieces are present per 1 cm in the longitudinal direction. 3. The bulky nonwoven fabric according to claim 1, wherein the streak-like low-density region is formed by an opening. 4. The heat-shrinkable fiber having a maximum heat shrinkage of at least 50%, wherein the first heat-shrinkable fiber has a maximum heat shrinkage of 30% by weight.
The bulky nonwoven fabric according to claim 1, which is a fiber layer containing the above. 5. The fiber layer according to claim 1, wherein the second fiber layer does not substantially shrink at a temperature at which the first fiber layer shrinks.
3. The bulky nonwoven fabric according to any one of 3. 6. A second fiber layer which does not substantially shrink at a temperature at which the first fiber layer thermally shrinks is laminated on at least one surface of the first fiber layer having the property of thermally shrinking by heat, and a high-pressure water flow The pre-entangled web preliminarily entangled by spraying at an interval of 1.5 mm or less is placed on a support for forming an opening,
A high-pressure water stream is streaked at intervals of 2 to 15 mm in a direction perpendicular to the longitudinal direction to form streaked aligned openings, and then heat-treated to heat the first fiber layer. A method for producing a bulky nonwoven fabric, wherein the bulky nonwoven fabric is contracted to form a ridge in the second fiber layer between the streaks. 7. A cleaning material using the bulky nonwoven fabric according to any one of claims 1 to 5.