JP2008031569A - Method for producing nonwoven fabric - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a nonwoven fabric, which is capable of producing a nonwoven fabric having highly balanced longitudinal/transverse strength in one stage. <P>SOLUTION: One or more webs are formed from a fiber raw material composed of staple fibers by a roller carding machine (combing web-forming machine) 12 and the constitution fibers of the web or the laminated web of the web are entangled and bonded to form the nonwoven fabric. First fiber (non-crimped fiber) composed mainly of a bundled fiber tow or fiber bundle having little crimp and second fiber (crimped fiber) composed of a crimped fiber are used as the fiber raw material, the fibers are blended at a prescribed ratio and supplied to a roller card 12, and the opened (combed) fiber aggregate is peeled from the doffers 24, 24A of the roller card 12 while being beaten by fly combs 26, 26A to form webs 28, 28A. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a nonwoven fabric through a step of forming a web using a fiber-type web forming machine such as carding or garnet. More specifically, the invention relates to a method for manufacturing a nonwoven fabric, which is easy to adjust the ratio of the vertical / horizontal strength, and particularly suitable for manufacturing a nonwoven fabric having a vertical / horizontal strength ratio close to 1.

  Conventional non-woven fabrics using crimped short staple synthetic fibers are superior in either the vertical or horizontal direction due to the nature of the manufacturing method, and the vertical / horizontal strength balance is excellent. It was not taken.

  In order to solve this, 1) Another non-woven fabric with a different balance of length and width compared to the non-woven fabric is bonded in the online process or offline process. 2) The non-woven fabric is warped in the post process or in the horizontal direction. The fiber orientation balance was relaxed by pulling it extremely, and the vertical and horizontal balance was maintained.

  However, in the above method 1), the production is not completed in one step, and an extra man-hour is required. Furthermore, since another nonwoven fabric is required, the cost increases. In the above method 2), there is a limit to the tension, and the level of vertical / horizontal balance is not as high as that until the reverse.

Although it does not affect the patentability of the present invention, for example, Patent Documents 1 and 2 exist as known literatures for manufacturing nonwoven fabrics having excellent vertical strength.
Japanese Unexamined Patent Publication No. 7-3604 (abstract, claims, etc.) Japanese Patent Laid-Open No. 61-70060 (claims, fields of industrial use, etc.)

  In view of the above, it is an object of the present invention to provide a method for producing a nonwoven fabric capable of producing a nonwoven fabric having an excellent balance of vertical and horizontal strength in one step.

  The present inventors have advanced the development to achieve the above-mentioned problems, and include non-crimped fibers mainly composed of bundled fibers with almost no crimps, or thermoplastic synthetic fibers having crimps, etc. When the web is formed by mixing the crimped fibers made of, and separating the fibers that have been spread (opened) transferred to the doffer in the fiber web forming machine such as a roller card from the doffer with a doffer comb, By adopting a fly comb as a doffer comb and hitting it, the thick fiber bundle is turned sideways, and the finely spread fibers are turned sideways to form a web, which solves the above problems. (A nonwoven fabric with controlled vertical / horizontal balance can be provided in one step), and the present invention has been conceived.

In a method for producing a nonwoven fabric by forming one or more webs from a fiber material of short fibers using a fiber-type web forming machine, and entangled the constituent fibers of the web or the laminated web of the webs,
As said fiber raw material, the 1st fiber (non-crimped fiber) which consists of a bundle-like fiber (bundle strand or tow) with almost no crimps, or has a bundle-like fiber as a main component, and a fiber having crimps The second fibers (crimped fibers) made of the above are mixed at a predetermined ratio and supplied to a fiber-forming web forming machine, and the fiber assembly after opening (crimping) is fried from the doffer or cylinder of the web-forming machine. It is characterized in that it is peeled off with a comb to form a web.

Said structure WHEREIN: As said fiber raw material, while setting it as the mass mixing ratio of said 1st fiber / said 2nd fiber = 30 / 70-90 / 10, the basis weight of a web (one sheet) is 20-100 g / it is preferable that the m ^2. If the first fiber is too small, it is difficult to secure the transverse strength of the nonwoven fabric. On the other hand, if the second fiber is too small, the fibers are not entangled and the web is difficult to form.

  It is desirable that the bundled fibers constituting the first fiber have a chopped strand number of 1 to 100 k. When the number of bundle fibers is too small, it is difficult to turn the sideways (CD) when knocked down with a comb, and it is difficult to secure the transverse strength of the nonwoven fabric. On the other hand, when the number is too large, the second fibers are likely to be relatively insufficient. In the same manner as described above, it becomes difficult to form a web.

  It is desirable that the material of the first fiber is an inorganic fiber and the material of the second fiber is a thermoplastic synthetic fiber. This is because inorganic fibers are mainly chopped strands that are not twisted, and many have high strength. In addition, thermoplastic synthetic fibers are mainly twisted and have a wide selection.

  Moreover, it is desirable that the thermoplastic synthetic fiber includes 50% or more of an adhesive fiber made of a heat fusion component or containing a heat fusion component. When a heat treatment step is included during the production of the nonwoven fabric, or when the nonwoven fabric is thermoformed, a high strength nonwoven fabric or molded product can be obtained.

  And each said manufacturing method is applicable to the method of adjusting and adjusting the length / width strength ratio of the said nonwoven fabric to the range of 25/75-90/10.

  In the present invention, non-crimped fibers and crimped fibers are mixed, and a fiber bundle of non-crimped fibers (chopped strands) is intentionally left and transferred to a doffer, and the fiber bundle is fly-comb (doffer comb) The fiber orientation is in the transverse direction (CD). In this state, the web is formed by peeling off from the doffer, so that it is possible to obtain a nonwoven fabric excellent in the vertical and horizontal fiber orientation in one step.

  That is, in the method for producing a nonwoven fabric of the present invention, the fiber bundle having the doffer remaining in the reed web-forming machine is turned sideways by hitting the fiber bundle with a fly comb, and the fiber bundle having no fiber bundle remaining is warped. Remove the web as it is facing to make a web. A nonwoven fabric having excellent vertical and horizontal balance can be produced by entanglement of the constituent fibers as they are or by stacking two or more webs.

  With the nonwoven fabric of the present invention, it is possible to obtain a nonwoven fabric with an excellent vertical / horizontal balance in a single process simply by changing the mechanical conditions, which can be expected to be applied to a wide variety of products and cost performance. (Compared to cost effectiveness)

  Hereinafter, the present invention will be described in detail based on embodiments. In the following description, the blending units (“%”, “ratio”, etc.) are mass (weight) units unless otherwise specified. Further, the present embodiment will be described by taking as an example the case where the fiber assembly is peeled off from the doffer with a doffer comb (fly comb), but can also be applied to the case where the fiber assembly is peeled off directly from the main cylinder without using the doffer.

  The method for producing a nonwoven fabric of the present invention is a nonwoven fabric in which one or more webs are formed from short fiber raw materials using a fiber-type web forming machine, and the constituent fibers of the web or the laminated web of the webs are entangled. In the method, the first is mainly composed of bundle fibers (tow) with almost no crimps or mainly bundle fibers (tow 50% or more). The fibers and the second fibers made of crimped fibers are mixed in a predetermined ratio and supplied to the fiber-type web forming machine, and the fibers (aggregates) transferred to the doffer in the web forming machine are beaten with a doffer comb. Peeling to form a web.

  The flowchart of the nonwoven fabric manufacturing apparatus provided with the fiber type web forming machine in FIG. 1 is shown.

  Here, a roller card 12 is taken as an example of a fiber type web forming machine, but a garnet machine can be used instead. Moreover, although the thing provided with the heat melting furnace (drying furnace) 13 which performs fiber entanglement by thermal bonding entanglement is taken for an example, it replaces with the heat melting furnace 13 and replaces with mechanical entanglement apparatuses, such as a needle lock, or uses together. Of course, it is also possible. The mechanical entanglement device is usually arranged in front of the example of the hot melting furnace.

  The raw material fibers supplied to the hopper 14 in a mixed state at a predetermined ratio are supplied from the feeder 18 to the main cylinder 16 of the roller card 12 through the take-in roll 19 and the transfer roll 20. The main cylinder 16 has a plurality of strippers 21 / workers 22 (three sets in the illustrated example) arranged on the outer periphery, and fibers (aggregates) between the walker 22 and the main cylinder 16 are arranged. Carded. That is, by repeating the transition of the fibers (aggregates) on the main cylinder 16 to the stripper 21 / walker 22 and the return from the walker 22 to the main cylinder 16, the fibers (aggregates) are finely (opened). Done.

  (1) As the first fiber (bundle-shaped crimped fiber), what is called a chopped strand (cut tow) is used. The number of constituent fibers of the fiber bundle (tow) is preferably in the range of 1K (1000) to 100K (100,000), more preferably in the range of 3k to 24k, and the cut length is in the range of 20 to 70 mm. Furthermore, it is desirable that it exists in the range of 35-60 mm.

  Moreover, the characteristic (tow) of the first fiber has a tensile strength (JIS L1015; the same applies hereinafter): 1 to 7 GPa, further 0.3 to 0.8 GPa, and a flexural modulus (JIS L1015; the same applies hereinafter): 100 to 1000 GPa. Furthermore, it is desirable to use one having 200 to 500 GPa, average fineness: 1 to 100 dtex, and further 3 to 12 dtex.

  The material of the first fiber (non-crimped fiber) is not limited to the material as long as it satisfies the above characteristics, and may be an organic synthetic fiber. Fiber), glass fiber, basalt fiber, alumina fiber and the like are desirable.

  (2) As the second fibers (crimped fibers), those having a crimping degree of 5 to 20 pieces / inch, and further 8 to 13 pieces / inch are used. And other characteristics of the second fiber are, from the viewpoint of card passing property, tensile strength: 0.1-1 GPa, further 0.3-0.8 GPa, flexural modulus: 0.4-20 GPa, It is desirable to use 2-10 GPa, average fineness: 1-100 dtex, and further 3-12 dtex.

  The material of the second fiber is not particularly limited as long as it has the above-mentioned characteristics, but usually thermoplastics such as polypropylene (PP), polyethylene (PE), polyester (PET), nylon, aramid, etc. from which crimped products can be easily obtained. Use synthetic fibers. The cut length is preferably in the range of 21 to 200 mm, and more preferably in the range of 51 to 76 mm.

  Normally, the orientation of the fibers (aggregates) that move from the cylinder 16 of the roller card 12 to the doffer 24 and come to the fly comb 26, which is the stripping position, is almost vertical when the roller card is viewed in the machine direct direction. That is, the non-woven fabric prepared by thermal bonding and / or mechanical entanglement bonding (needle punching) of the web as it is peeled off (spun) from the doffer 24 is vertical (warp) according to its fiber orientation. Or it becomes excellent only in the tensile strength of the side (weft).

  However, when the mixed raw fiber composed of non-crimped fibers (first fibers) is crimped into the crimped fibers (second fibers), mixed and dispersed, and put into the roller card 12 through the hopper 14, the tensile strength A balanced nonwoven fabric can be obtained. The reason is estimated as follows.

  By feeding the mixed raw material fibers into the roller card 12 (main cylinder 16 via the take-in roll 19 and transfer roll 20) with the fiber bundle of the first fibers remaining almost, the doffer 24 (24A In the fiber assembly that has shifted to (), the fiber bundle remains in the vertical direction (MD: machine direction) without crimping even after fibering (opening). The fiber bundle of the non-crimped fibers in the vertical direction on the doffer 24 (24A) is hit with the fly comb 26 (26A) so that the fiber bundle is turned sideways and peeled off from the doffer 24 (24A). It is taken (spun) to form the web 28 (28A).

  That is, in the case of crimped fibers, there are differences depending on the denier, cut length, and supply amount of the fibers, but until the fiber lump almost disappears during the carding process, and the fibers become one by one. The fibers are spread and each is lightly entangled to form a web shape and move to the doffer 24 (24A). However, the non-crimped fiber remains as a fiber bundle in a state of being almost floated independently without entanglement of fibers due to its rigidity. By hitting the floated fiber bundle with a fly comb, the MD fiber bundle is oriented in the cross direction (CD). The phenomenon suitable for CD is more noticeable as the fiber bundle is thicker.

  In other words, when you want to gain a balanced balance, select the one with a large number of tow (fiber bundles) and leave many thick fiber bundles when they are peeled off (spun) from the card. I will increase the amount of fiber that faces. However, the thickness of the fiber bundle can also be controlled (adjusted) depending on the state of pre-opening before the card is inserted and the state of the action inside the card.

  In addition, the roller card used for said carding will not be specifically limited if a synthetic fiber can be carded. It is desirable to include at least a transfer roll 20, a main cylinder 16, and doffers 24 and 24A. The doffer comb used must be the fly combs 26 and 26A. In the case of a rotary comb, the fiber bundle is discharged as it is faced.

  Note that the fly comb 26 (26A) is as shown in FIG. 2, and includes a plurality of comb plates 36 (four in the illustrated example) having a wavy tip side in parallel with the rotating shaft 35 that rotates swayingly. It is attached via the arm 37. In the illustrated example, 38 is a swing arm mounting block of the fly comb 26 (26A).

  Moreover, the roller card | curd 12 can respectively form (spin) the web from which fiber orientation differs by using a single doffer type, a double doffer type, a triple doffer type, or a 2 series straight card.

  The case of the double doffer type roller card 12 shown in FIG. 1 will be described as an example.

  Since the first fibers (non-crimped fibers) are transferred to the first doffer 24 in a thick fiber bundle state, a web having a large number of first fibers facing the side is formed from the first doffer 24. Further, since the first dough 24A is transferred in a state of a thin fiber bundle in which the opening of the first fibers has progressed, the first fibers (non-crimped fibers) from the second doffer 24A have a vertical orientation. A web with a large amount of is formed. This is because the opening of the fiber proceeds between the first doffer and the second doffer.

  In other words, by superimposing two webs at the same time, it is possible to obtain an apparently single web with a balance of vertical and horizontal fiber orientation.

  In addition, since the double doffer is overlapped with the web having a different opening degree as compared with the single doffer, the vertical / horizontal balance is easily obtained, and the productivity is improved by almost twice.

  Furthermore, the fiber orientation greatly changes in the subsequent process of the web. After the web is discharged, the web is laminated with a general cross layer, and the fibers are entangled with a needle punch to form a sheet. In this construction method, in the web state discharged in the carding process, the non-crimped fiber bundle is discharged sideways, but by laminating with a cross layer, the direction of the fiber bundle is the direct direction of the needle punching machine ( When viewed in the (feeding direction), the direction is reversed in the vertical direction, and further, it is possible to increase the strength in the vertical direction by pulling during the needle punching process. In this method, the vertical / horizontal balance can be freely adjusted by a combination of the fiber orientation in the carding process and the needle punching process.

However, in this method, webs with a lot of primary fibers (non-crimped fibers) (many fiber bundles) are weakly entangled with each other, so the web itself is weak in strength and has a lot of scale. It is necessary to increase the number of webs to be increased to some extent. For this reason, it is very difficult to produce a nonwoven fabric having a basis weight lower than about 100 g / m ² .

  Therefore, as another construction method, there is a construction method in which the web discharged from the card is laminated by a cross layer and then mechanically entangled by needle punching, and is melted and cooled and solidified as shown in FIG.

  In this case, more than half of the thermoplastic synthetic fiber, which is a constituent fiber of the second fiber (crimped fiber), is used as an adhesive fiber. As the adhesive fiber, either a single-type heat-sealing fiber or a composite-type heat-sealing fiber may be used. Polypropylene (PP) fiber or polyethylene (PE) fiber can be preferably used as the single-type heat fusion fiber. The composite heat-sealing fiber is a fiber having a predetermined cross section made of polymers having different melting points, and includes a core-sheath type (core-sheath type), a parallel type (side-by-side type), and the like. PP / PE, PP / EVA, PET / PE, PET / PET, and the like are known as this composite heat-fusible fiber.

The first fiber (non-crimped fiber) and the second fiber (crimped fiber) are usually mixed with the former / the latter = 30/70 to 90/10, preferably 50/50 to 70/30. To do. When the ratio of the second fibers (crimped fibers) is too small, there are few thermal bonding entanglement points between the fibers, and it is difficult to obtain sufficient strength for the nonwoven fabric. On the other hand, if the ratio of the first fibers (non-crimped fibers) is too small, the fiber bundles facing the web-like weft that moves from the roller card to the doffer will decrease, and it will be difficult to adjust the vertical and horizontal strength. Become. In addition, the basis weight of the web (one sheet) is preferably 30 to 100 g / m ² .

In the case of this construction method, the web discharged from the card is formed into a sheet as it is, so there is a limit on the upper limit weight (for example, 100 g / m ² ) depending on the card capacity. If the basis weight exceeds the upper limit, the dispersibility is extremely lowered, which may lead to lump unevenness or damage to the card.

  In order to obtain a sheet by heat melting and solidifying as described above, the webs 28 and 28A containing adhesive fibers (hot melt adhesive components) are passed through the heat melting furnace 13 while being sandwiched between the pressure conveyors 32 and 32, and heated. Then, it is cooled in the cooling furnace 15 in the sandwiched state.

  Here, as the pinching conveyors 32 and 32, a glass cloth belt coated with a heat-resistant fluororesin, a glass fiber whose surface is coated with a fluororesin, or a mesh belt using an aramid fiber can be suitably used. If these belts are not coated with a fluororesin, the molten resin will adhere to the belt surface, making it impossible to release the mold, making it impossible to obtain a heat-bonded nonwoven fabric.

  The heating temperature at this time is equal to or higher than the temperature at which the molten component of the adhesive fiber melts, and is preferably 180 ° C. or higher when the molten component is polypropylene.

  In this case, since the web laminates 28 and 28A are continuously heated and cooled, the transition from the adhesive fibers to the interface of the hot melt component to the web laminate is performed smoothly, and the temperature change from heating to cooling is further achieved. Since there is a time lag, it becomes easy to melt the melted component by pressing, and a sheet having high strength can be obtained.

  Hereinafter, the present invention will be described specifically by way of examples. In addition, the tensile strength (tensile strength) in an Example was measured according to the method prescribed | regulated to "JISL-1085".

  In the following, a heat melting furnace 13 that is a heating and melting means used was one in which hot air that passed through a heat exchanger heated by circulation of heat medium oil at 270 ° C. circulated. As the pinching conveyors 32 and 32 for laminating and pressing the webs, an aramid mesh conveyor coated with a fluororesin was used.

<Example 1>
As fibers used in the nonwoven fabric, non-crimped fibers are carbon fibers (the number of tow fibers: 12K, fiber length: 35 mm, mixing ratio: 50%), thermoplastic synthetic fibers are polypropylene short fibers (melting point: 170 ° C., fineness: 6.6 dtex, fiber length: 51 mm, mixing ratio: 50% by weight) were each fed to a blender and blended.

  Then, this mixed cotton is put into the hopper 14, and from the feeder 18, the main cylinder 16, the first and second doffers 24, 24 A, the fly comb (doffer) through the take-in roll 19 and the transfer roll 20 having a width of 2000 mm. Comb) 26 and 26 A were continuously fed to the roller card 12 provided with the feeder 18.

While continuously laminating the webs 28 and 28A prepared by the roller card 12, the webs 28 and 28A were sandwiched between the press conveyors 32 and 32, and fed into a hot furnace to be melted. When the material temperature at that time was confirmed with a thermolabel, it was 185 ° C. Furthermore, after passing through a cooling furnace in which air at normal temperature circulates continuously after heat melting, solidification was performed, and then separation from the pressure-carrying conveyors 32 and 32 was performed to prepare a nonwoven fabric having a basis weight of 50 g / m ² .

  When the tensile strength of the nonwoven fabric was measured, the warp was 30 N / 5 cm, and the width was 24 N / 5 cm.

<Example 2>
Example 1 was prepared in the same manner as in Example 1 except that the rotation speed of the main cylinder 16 was increased by 25%. When the tensile strength of the nonwoven fabric was measured, the warp was 42 N / 5 cm and the width was 15 N / 5 cm.

<Example 3>
Non-crimped fibers are basalt fibers (number of tows: 6K, fiber length: 50 mm, mixing ratio: 70% by weight), thermoplastic synthetic fibers are polyester short fibers (fineness: 3.3 dtex, fibers) (Length: 51 mm, mixing ratio: 30%) are fed to the blender and blended, and then the cylinder rotation speed of the spreader that passes when the blended cotton (fiber assembly) is fed to the hopper is the minimum machine capacity requirement. By lowering to 120 min ⁻¹ , the opened state of the basalt fiber was suppressed.

This mixed cotton was continuously supplied to a roller card 12 equipped with a take-in roll 19 having a width of 1300 mm, a transfer roll 20, a main cylinder 16, three sets of strippers 21 / walker 22, a first doffer 24, and a fly comb 26. At this time, the speed of the main cylinder 16 was reduced to the minimum mechanical capacity condition (200 min ⁻¹ ) to suppress the opened state of the basalt fiber.

The web obtained from the card was put into the cross layer as it was and the web was laminated. Further, the obtained web sheet was pulled by applying a 160% difference in speed between the first roll and the final roll in the drafting process, and then subjected to needle punching to prepare a nonwoven fabric. The needle point at this time was 100 points / cm ² .

The basis weight of the nonwoven fabric was 300 g / m ² . Moreover, when the tensile strength of this nonwoven fabric was measured, the length was 216 N / 5 cm and the width was 208 N / 5 cm.

<Example 4>
In Example 3, the cylinder rotation speed of the opening machine when feeding to the hopper is increased by 50%, the rotation speed of the main cylinder of the card is increased by 50%, and the speed difference in the drafting process is made 110%. Prepared as in Example 3.

  When the tensile strength of the nonwoven fabric was measured, the warp was 134 N / 5 cm, and the width was 329 N / 5 cm.

<Comparative Example 1>
In Example 1, a nonwoven fabric was prepared in the same manner as in Example 1 except that the mixing ratio of polypropylene, which is a thermoplastic synthetic fiber, was 100%.

  The tensile strength of the nonwoven fabric was measured. As a result, the warp was 48 N / 5 cm and the width was 8 N / 5 cm.

<Comparative example 2>
In Example 1, a non-woven fabric was prepared in the same manner as in Example 1 except that the width of the card was 1500 mm and a rotary comb was used without using a fly comb.

  When the tensile strength of the nonwoven fabric was measured, the warp was 53 N / 5 cm, and the width was 11 N / 5 cm. As a result, the fiber orientation balance was large and turned vertically.

<Comparative Example 3>
In Example 1, a nonwoven fabric was prepared in the same manner as in Example 1 except that a stainless steel conveyor that was not subjected to fluororesin processing was used as the material of the mesh conveyor of the heating furnace to be used.

  However, the solidified molten resin could not be released while attached to the conveyor surface, and a nonwoven fabric could not be prepared.

<Results and discussion>
Table 1 shows the test results of the above Examples and Comparative Examples.

  From Table 1, the method of each example is the one with excellent vertical / horizontal strength balance (Examples 1 and 3), or the vertical / horizontal strength balance is within a predetermined range (3/1 to 1 / 3) It can be seen that a vertical strength higher than the horizontal strength (Example 2) and a horizontal strength higher than the vertical strength (Example 4) can be obtained. On the other hand, it can be seen that the nonwoven fabrics obtained by the methods of Comparative Examples 1 and 2 are each a nonwoven fabric having an extremely high vertical orientation in which the vertical strength is not much higher than the horizontal strength and is not well balanced.

It is a flowchart which shows an example of the apparatus used for the manufacturing method of the nonwoven fabric of this invention. It is a perspective view of the fly comb in the apparatus shown in FIG.

Explanation of symbols

12 Roller Card 13 Heat Melting Furnace 14 Hopper 16 Cylinder 24 First Doffer 24A Second Doffer 26, 26A Fly Comb 28, 28 Web 30 Nonwoven Fabric

Claims (6)

In a method for producing a nonwoven fabric by forming one or more webs from a fiber material of short fibers using a fiber-type web forming machine, and entangled the constituent fibers of the web or the laminated web of the webs,
As said fiber raw material, the 1st fiber (non-crimped fiber) which consists of a bundle-like fiber (bundle strand or tow) with almost no crimps, or has a bundle-like fiber as a main component, and a fiber having crimps The second fibers (crimped fibers) made of the above are mixed at a predetermined ratio and supplied to a fiber-forming web forming machine, and the fiber assembly after opening (crimping) is fried from the doffer or cylinder of the web-forming machine. A method for producing a nonwoven fabric, characterized in that a web is formed by peeling off with a comb. The fiber raw material has a mixing ratio of first fiber / second fiber = 30/70 to 90/10, and the basis weight of the web (one piece) is 20 to 100 g / m ^2. The manufacturing method of the nonwoven fabric of Claim 1.   The method for producing a nonwoven fabric according to claim 2, wherein the number of bundle fibers of the bundle-like fibers constituting the first fibers is 1 to 100 k.   4. The method for producing a nonwoven fabric according to claim 1, wherein the material of the first fiber is an inorganic fiber, and the material of the second fiber is a thermoplastic synthetic fiber.   The method for producing a nonwoven fabric according to claim 4, wherein the thermoplastic synthetic fiber includes 50% or more of an adhesive fiber made of a heat fusion component or containing a heat fusion component.   The method for producing a nonwoven fabric according to any one of claims 1 to 5, wherein a length / width ratio of the nonwoven fabric is adjusted to a range of 25/75 to 90/10.

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