JP2001146633A - Fluororesin fiber and sheet and their production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluororesin fiber giving a sheet having excellent performance to collect fine dust and toner, entanglement of constituent fibers and dimensional stability and exhibiting small deformation in fabrication, a sheet manufactured with the fiber and their production process. SOLUTION: The fluororesin fiber is a drawn single fiber split into plural split fibers. The number of the split fibers has distribution in the direction of fiber length and the minimum fineness of the split fiber is <=0.1 dtex. The fiber can be produced by spinning, baking and thermally drawing a fluororesin and fibrillating the produced fluororesin fiber by water-jet punch treatment or grinding or beating treatment. A sheet made of the fiber base containing the above fluororesin fiber is subjected to water-jet punch treatment or grinding or beating treatment to effect the fibrillation of the fluororesin fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to heat resistance, chemical resistance, low coefficient of friction or low dielectric constant,
The present invention relates to a fluororesin-based fiber capable of providing a sheet-like material having excellent entanglement, further having a small elongation and excellent dimensional stability, and having a small deformation during molding, a sheet-like material, and a method for producing the same. is there.

[0002]

2. Description of the Related Art Fluororesin-based fibers are unique in comparison with other polymer materials because of their excellent properties, such as heat resistance, chemical resistance, low coefficient of friction or low dielectric constant, and are used for industrial materials. Widely used. Furthermore, woven fabrics, knitted fabrics, nonwoven fabrics, papers, and the like are known as sheet-like products using fluororesin-based fibers. Above all, the tetrafluoroethylene resin fiber is produced by mixing 3d (3.3 dte) by a manufacturing method in which fine particles of the polytetrafluoroethylene resin and a polymer substance are mixed and spun.
x) Fine fibers of the order of magnitude are obtained commercially.

[0003] However, with respect to the toner encapsulant, finer toner particles have been developed due to the colorization of the toner, and the fineness of the fibers used for the encapsulant has been required. From the viewpoint of improving collection efficiency, finer fibers are required.Furthermore, even in printed circuit board materials, it is not preferable that variations in the dielectric constant depending on the location due to miniaturization of the circuit occur. In addition, finer fibers are required. Further, when a paper made by wet papermaking is used as a material for a printed circuit board, the currently commercially available expanded PTFE fiber is:
There is a problem that the entanglement between the fibers is weak and papermaking cannot be performed without a binder.

[0004] Therefore, by using an undrawn yarn of PTFE fiber and utilizing the flexibility and surface properties of the undrawn yarn, the adhesiveness of the undrawn yarn or the adhesiveness of a spinning aid contained in the undrawn yarn, A paper-like material consisting only of fluorine fibers has been obtained (Japanese Patent Laid-Open No. 3-99793). However, the paper-like material obtained by this method has drawbacks in that since the undrawn yarn is used, the paper-like material has a large elongation, is inferior in dimensional stability, and has a large deformation during molding.

[0005] On the other hand, with regard to the fineness of the tetrafluoroethylene resin fiber, according to JP-A-63-126911,
It has been proposed that by mixing seawater-island composite spinning by mixing tetrafluoroethylene resin fine particles and a polymer substance, an ultrafine product of the fiber can have a fineness of 0.09 d (0.1 dtex). However, there is no evidence that the microfibers obtained by such techniques are commercially available.

Further, according to Utility Model Registration No. 2571634, a window glass stabilizer in which a fluororesin-based fiber is tufted or needle-punched into a nap-up fabric, and abrasion treatment is performed with a sheet glass to form a fibrillated tip and is worn out. Has been proposed to be obtained. However, in the sheet-like material obtained by this technique, only the ends of the fibers are fibrillated and worn away, and the fineness of the entire sheet-like material required for a toner sealing material, a filter material, and a material for a printed circuit board is required. It was completely inadequate for making the fibers finer, and it was also completely insufficient for strengthening the entanglement between the fibers.

Further, since the fluororesin-based fiber has an extremely small coefficient of friction between the single fibers, for example, when cut into a predetermined size from a raw material of felt, the single fibers are detached from the cut surface,
There was a problem that it became a kind of garbage and generated dust.

[0008]

SUMMARY OF THE INVENTION In view of the background of the prior art, the present invention provides a fluororesin-based fiber without impairing its properties such as heat resistance, chemical resistance, low dielectric constant and low coefficient of friction. Provides a sheet-like material that excels in collecting finer dust and toner, excels in entanglement between constituent fibers, has low elongation, has excellent dimensional stability, and has little deformation during molding. It is intended to provide a fluororesin-based fiber, a sheet-like material, and a method for producing the same, which can be performed.

[0009]

The present invention employs the following means in order to solve the above problems. That is, the fluororesin-based fiber of the present invention is a stretched single fiber having a split fiber divided into a plurality of fibers, and the number of the split fibers has a distribution in a length direction of the fiber, In addition, the minimum fineness of the split fibers is 0.1 dtex or less.

[0010] The method of producing such a fluororesin fiber is as follows: spinning by matrix spinning, emulsion spinning, or paste extrusion, firing, and then hot drawing the fluororesin fiber to obtain a water jet punch. Or fibrillation by crushing or beating.

Further, the method for producing a sheet-like material according to the present invention comprises:
After spinning by a matrix spinning method, an emulsion spinning method or a paste extrusion method, firing, and then performing a water jet punch treatment on a sheet-like material composed of a fiber base material containing a fluororesin-based fiber obtained by hot drawing,
Alternatively, the fluororesin fibers are fibrillated by crushing or beating.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made to solve the above problems, that is, fine dust and fine particles without impairing the properties of the fluororesin fiber, such as heat resistance, chemical resistance, low dielectric constant and low coefficient of friction. Fluororesin that has excellent toner collecting properties, excellent entanglement between constituent fibers, low elongation and excellent dimensional stability, and can provide a sheet-like material with small deformation during molding. The system fiber was studied diligently, and when it was made into a fiber having a specific fibril,
It is surprisingly sought to solve these problems at once.

The minimum fineness of the fluororesin fiber of the drawn yarn provided by the present invention is preferably 0.1 dtex or less. Because fibrillated fibers with a minimum fineness of 0.1 dtex or less, when formed into a sheet, exhibit a filter function that efficiently filters fine dust contained in strong acids, strong alkalis, high-temperature chemicals, or high-temperature gases. I found that I can do it.

As the fluororesin fiber of the present invention, any fiber may be used as long as 90% or more of the repeating structural units of the polymer are composed of monomers containing at least one fluorine atom in the main chain or side chain. However, a fiber composed of a monomer having a large number of fluorine atoms is more preferable. For example, an ethylene tetrafluoride-hexafluoropropylene copolymer (FE)
P), a tetrafluoroethylene-perfluoroalkoxy group copolymer (PFA) or a tetrafluoroethylene-olefin copolymer (ETFE) can be exemplified. More preferably, polytetrafluoroethylene (PTFE) is used from the viewpoint of heat resistance or dielectric constant.

The fluororesin fiber is preferably produced by a conventionally known matrix spinning method, and a fiber obtained by conventionally known emulsion spinning or paste extrusion may be used without any problem.

The matrix spinning method referred to herein is described, for example, in Japanese Patent Publication No. 42-3691 (US Pat. No. 2,771).
No. 2,444), this is a production method in which a dispersion of polytetrafluoroethylene using a viscose matrix as a matrix is wet-spun, then fired and heat-fused at 340 to 400 ° C., and then hot-drawn. Further, the emulsion spinning method is to mix a suitable binder such as a cellulose-based binder into an emulsion solution of polytetrafluoroethylene, spin the mixture, desorb the emulsion solvent, and further sinter and stretch the yarn. This is a production method capable of removing only the binder component. Furthermore, the paste extrusion method is a production method in which a rod-shaped material is molded from a mixture of polytetrafluoroethylene powder and a wax-like lubricant, the lubricant is removed, and then a stretching treatment is performed.

The fluororesin fibers of the present invention also include fibrous materials obtained by slitting rods obtained by the paste extrusion method. Furthermore, after forming the polytetrafluoroethylene powder into a cylindrical shape under high temperature and high pressure, cut it into a thin and wide film shape along the outer circumference, further slit, and heat-stretch to obtain a fibrous shape. Objects can be used without any problem.

The fluororesin-based fiber having the split fiber according to the present invention is produced by a water jet punching process. The water pressure of the water jet punching process is 4.9 × 10 ⁶ N / m ^{2 to} 19.6 × 10 ⁶ N / m.
m ² is good. When the water pressure is less than 4.9 × 10 ⁶ N / m ² , the fiber does not split due to insufficient physical impact, and at a high pressure exceeding 19.6 × 10 ⁶ N / m ² ,
This is because the nozzle of the water jet punch device cannot withstand the water pressure and breaks.

The processing time of the water jet punch is preferably 5 to 20 seconds. If the processing time is less than 5 seconds, the physical impact is short, so that the fibers are not split. If the processing time is more than 20 seconds, the fibers are entangled on the sample conveyor of the water jet machine, so that the fibers are easily entangled. Is not peeled off, or
This is because the split fibers are finely cut and flow with the treated water.

As for the form of the drawn fiber at the time of the water jet punching treatment, it is preferable to continuously perform the water jet punching treatment while winding the filament of the fluorine fiber or winding it directly from the bobbin. When wound in a skein, the total fineness is preferably 300,000 dtex or less. This is because if the yarn amount exceeds 300,000 dtex, the area directly hit by the water flow becomes small, and a sufficient physical impact cannot be obtained.

Furthermore, the fluororesin fiber having the split fiber of the present invention can be fibrillated or pulped by mechanical crushing or beating.
The mechanical crushing means can be obtained, for example, by putting the fibers into a mortar and continuously treating the fibers with a pestle for 60 minutes or more. The fluororesin fiber pulp obtained preferably has a freeness of 800 ml or less. Because the freeness is higher than 800 ml, it means that the fibers are not well divided. Such freeness is measured based on JIS P-8121 (Canadian standard type).

The sheet-like material of the present invention preferably contains the fluororesin fiber in an amount of preferably at least 5% by weight, more preferably at least 20% by weight, further preferably at least 50% by weight. This is because a sheet-like material having a content of the fluororesin-based fiber of less than 5% by weight cannot capture fine dust when used as a filter, and exhibits only the same collection efficiency as a conventional filter. It is. Further, in the case of a sheet-like material having a content of the fluororesin-based fiber of less than 50% by weight, when used as a material for a printed circuit board, the dispersibility of the fiber is poor, and the dielectric constant of each part of the sheet-like material is not uniform. This is because only a certain kind of printed board material can be obtained.

Further, the sheet-like article of the present invention can provide a sheet-like article in which the voids in the sheet-like article are miniaturized or the dispersibility of the fluororesin fiber is improved. Such a sheet-shaped material is used to provide a toner sealing material for a color printer which is reduced to fine particles, or a filter material capable of capturing finer dust, a material for a printed circuit board which does not vary in dielectric constant depending on a place, and the like. It is used effectively for

Further, according to the sheet-like material of the present invention, it is possible to provide a printed board material by wet papermaking without using a binder using only the drawn yarn of the fluororesin fiber. Such printed circuit board materials are:
Since the drawn yarn of the fluororesin fiber is used, a material for a printed circuit board which is excellent in dimensional stability with small elongation and small in deformation at the time of molding processing is provided as compared with a material using an undrawn yarn. be able to.

Further, the present invention has a problem that, for example, when cut into a predetermined size from a raw material of felt, a single fiber is detached from a cut surface and is generated as a kind of dust. By using a drawn yarn fluororesin-based fiber in which the entanglement between fibers is increased, it is possible to provide a sheet-like material in which the detachment of the fluororesin-based fiber is extremely small.

The sheet-like material in the present invention includes a woven fabric
There are knitted fabrics, nonwoven fabrics, and papers, and also includes structures obtained by combining these. These sheet materials are manufactured by a conventionally known method. By arranging the warp and weft at right angles and crossing it up and down, a woven fabric can be obtained, and a knitted fabric can be created by repeatedly making a loop with the thread and passing the thread through the loop again to make a loop can get. The nonwoven fabric can be obtained by carding short fibers to form a web molded body, and then tangling and integrating the fibers by needle punching or water jet punching. Paper can be obtained by wet papermaking. Since the paper obtained by the wet papermaking method is such that the fluororesin fibers of the drawn yarn constituting the paper are fibrillated and the drawn single fibers are divided into a plurality of fibers, the entanglement between the fibers is improved. In addition, it is possible to maintain the shape of the paper with 100% of the drawn resin, that is, without the binder.

The toner encapsulant of the present invention can be obtained by processing a fibril-divided fluororesin-based fiber into a woven fabric, nonwoven fabric or paper. By using the fibers, the voids of the toner sealing material can be miniaturized, and the sealing function for color toner, which is fine particles, can be sufficiently satisfied. In addition, the use of the fibrillated drawn fiber fluororesin-based fibers improves the entanglement between the fibers, so that even when the fibers are cut to a predetermined size, very few fibers are detached from the cut surface, and the generation of dust can be prevented. This toner encapsulant can be obtained by heat-treating, for example, a flocked material of the above-mentioned fibrillated drawn yarn fluororesin-based fiber to form a felt, and the like.

The filter material of the present invention can be obtained by processing the fibrillated drawn fiber fluororesin-based fiber into a woven fabric, nonwoven fabric or paper. This processing method can also be obtained by arranging a cut cotton of the drawn polytetrafluoroethylene fiber according to the present invention on a base cloth using, for example, polytetrafluoroethylene, and performing, for example, needle punching to integrate with the base cloth. Can be. By processing the filter material using the fibers, the surface area of the filter is dramatically improved, and the collection efficiency is improved. Furthermore, since the surface area of the filter is increased and the amount of ventilation of the filter can be suppressed to the same level as a filter made of non-fibrillated fluororesin fiber, a filter material with low pressure loss and high collection efficiency is provided. can do.

The printed circuit board material of the present invention can be obtained by processing fibril-drawn drawn resin fluororesin fibers into woven fabric or paper. It can be obtained by laminating a copper foil on a woven fabric or paper made of the fiber, and subjecting the thermosetting resin to vacuum pressing using an adhesive. By using at least one selected from the group consisting of an epoxy resin, a polyimide resin, a phenol resin, a fluororesin and an isocyanate resin as the thermosetting resin, it is possible to provide a resin having excellent practicability in terms of heat resistance.

The above-mentioned vacuum press treatment is a treatment in which a sample obtained by laminating a copper foil on a woven fabric or paper made of the fiber is placed in a vacuum atmosphere, set at a temperature higher than the thermosetting temperature of the thermosetting resin, and further applied pressure. It is. By etching the surface of the copper-clad laminate obtained by the vacuum press treatment, a sample for permittivity measurement can be obtained.

By processing a material for a printed circuit board using the fluororesin-based fiber, the dispersibility of the constituent fibers is improved,
A printed circuit board material having a uniform dielectric constant can be obtained.

As a method for obtaining a sheet-like material comprising a fluororesin fiber of the fibrillated drawn yarn of the present invention,
It can be obtained by processing a conventional stretched fluororesin-based fiber that has not been split into a sheet-like material by a known method, followed by a water jet punch treatment. According to this method, the surface of the sheet can be selectively fibrillated, and the fibrillation ratio can be adjusted by the processing conditions of the water jet punch.

[0033]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. (Example 1) PTFE multifilament (TOYOFLON400D-60F-2 manufactured by Toray Fine Chemicals)
00) is wound into a skein 600 times, water jet punched for 15 seconds, and fibrillated. Water pressure is 14.
It is 7 × 10 ⁶ N / m ² . The obtained multifilament 1 was cut into 70 mm to obtain a staple fiber 1. Next, a woven fabric made of PTFE multifilament (TOYOFLON # 4 manufactured by Toray Fine Chemicals Co., Ltd.)
378), the fibrillated staple fibers 1 are arranged on both sides of the front and back sides, and then 350 × 10 ⁴ fibers / m ²
Needle punching and integrated with felt processing
I got (Example 2) Multifilament 1 obtained in Example 1
Was cut into 2.0 mm to obtain a staple fiber 2. This staple fiber 2 is provided with a fluorinated surfactant Surflon (SURFLON S- manufactured by Asahi Glass Co., Ltd.).
131) was added thereto in an amount of 1% by weight, dispersed in water, and subjected to wet papermaking to obtain Paper 1. Further, an epoxy resin (EPICLON 1 manufactured by Dainippon Ink and Chemicals, Inc.) was added to the paper 1.
121N-80M) and kept at 155 ° C. for 10 minutes to semi-harden the resin. Five resin-impregnated sheets are laminated, and copper foil (JTC-1 / 2 Oz manufactured by Nikko Gould Foil Co., Ltd.) is provided on the upper and lower sides, and integrated,
Vacuum press treatment was performed at 2.94 × 10 ⁶ N / m ² at 60 ° C. for 60 minutes to obtain printed circuit board material 1. (Example 3) PTFE staple fiber (TOYOFLON 6.7d × 70m, manufactured by Toray Fine Chemicals)
m), and a woven fabric made of PTFE multifilament (TOYOF manufactured by Toray Fine Chemicals Co., Ltd.)
LON # 4378) on both sides, 350x
Needle punching treatment was performed at 10 ⁴ needles / m ² , and integrated to obtain a felt processed product. This felted product is subjected to water pressure 14.
Water jet punching was performed at 7 × 10 ⁶ N / m ² for 15 seconds to obtain a felt processed product 2 having a fibrillated surface. (Example 4) PTFE staple fiber (TOYOFLON 6.7d × 70m manufactured by Toray Fine Chemicals)
m), 1% by weight of a fluorinated surfactant Surflon (SURFLON S-131 manufactured by Asahi Glass Co., Ltd.) was added, and the mixture was collected in a mortar with a small amount of water, and crushed by 12%.
By carrying out for 0 minutes, fibrillated (pulp) PTFE fiber 1 having a freeness of 700 ml was obtained. Paper was obtained by subjecting the PTFE fiber 1 to wet papermaking. Further, the paper is impregnated with an epoxy resin (EPICLON 1121N-80M manufactured by Dainippon Ink and Chemicals, Inc.),
The resin was held at 155 ° C. for 10 minutes to partially cure the resin. Five such resin-impregnated sheets are laminated, and copper foil (JTC-1 / 2 Oz manufactured by Nikko Gould Foil Co., Ltd.) is provided on the upper and lower sides to be integrated, and is integrated at 170 ° C. and 2.94 × 10 ⁶ N / m ² .
Printed board material 2 by vacuum pressing for 0 minutes
I got (Example 5) The paper 1 obtained in Example 2 was heated at 160 ° C for 2 hours.
The sheet was calendered under the condition of 9.4 × 10 ⁶ N / m ² to form a bond by heat fusion to obtain a sheet 1 with improved strength. (Comparative Example 1) Fabric made of PTFE multifilament (TOYOFLON # 43 manufactured by Toray Fine Chemicals)
78) PTFE staple fiber (TOYOFLON 6.7dx manufactured by Toray Fine Chemicals Co., Ltd.)
70 mm), and needle punching was performed at 350 × 10 ⁴ needles / m ² to obtain a felt processed product 3. (Comparative Example 2) PTFE staple fiber (TOYOFLON 6.7d x 20mm, manufactured by Toray Fine Chemicals)
) Was made by wet paper making, but the sheet strength was weak and could not be processed into paper. Therefore, 50% by weight of an aqueous epoxy resin binder is added to the PTFE staple fiber,
After the wet papermaking, the paper was kept at 155 ° C. for 10 minutes, and the resin was semi-cured to obtain a resin-impregnated sheet. This resin impregnated sheet is
The copper foil (JTC-1 / 2 Oz manufactured by Nikko Gould Foil Co., Ltd.) was provided on the top and bottom, and integrated,
Vacuum press treatment was performed at 0 ° C. and 2.94 × 10 ⁶ N / m ² for 60 minutes to obtain printed circuit board material 3. (Comparative Example 3) PTFE obtained by emulsion spinning method
Using 50% of PTFE unstretched yarn cut to a length of 4 mm and 50% of PTFE fiber stretched and cut to a length of 6 mm, the raw material of which is stirred and mixed in water,
Paper 2 was obtained by wet papermaking. The paper 2 was subjected to a heat treatment at 400 ° C. for 1 minute using a far-infrared heater, and further subjected to a heat treatment at 380 ° C. for 2 hours using an electric thermostat.

The staple fibers 1 and pulped PTFE fibers 1 used in Examples 1 and 4 were measured for the number of split fibers. Moreover, the evaluation method of the sheet-like material produced in Examples 1-5 and Comparative Examples 1-3 was performed by the following method. Tables 1 and 2 show these results. [Number of divisions of fiber] An electron micrograph was taken at a magnification of 1000 times, and the diameter of the fiber existing every 5 μm in the length direction of the fiber was read. The number of divisions is determined from the ratio of the cross-sectional area of the undivided fiber to the cross-sectional area determined from the read fiber diameter. [Aeration] Measured by JIS L 1096 Frazier method. [Collection efficiency] Measured by gravimetric method. Wind speed 0.08m / s, used dust 10 kinds for JIS test, dust concentration 14 × 10 ^-3
The collection efficiency and the collection efficiency were calculated by measuring the amount of collection and leakage when dust was loaded on the sample under the conditions of kg / m ² and a dust loading time of 300 seconds. [Detachment from cut surface] A cut surface having a length of 3 cm was put into the sample with a single-edge razor for trimming made of stainless steel, and the number of single fibers detached from the cut surface was counted. [Dielectric constant] Measured by the method described in JIS C6481.
The copper foil of the printed circuit board material is processed into the specified shape by etching and then incorporated into the transformer bridge method measurement circuit and measured. The dielectric constant was calculated from the electrode area, the distance between the electrodes, and the capacitance of the measuring capacitor. The measurement frequency was 1 MHz. [Elongation] Measured by the method described in JIS P 8132. The size of the test piece was 200 mm in length and 15 mm in width, and the measurement was performed at a grip interval of 180 mm.

[0035]

[Table 1]

As is clear from the test results in Table 1, in the fibrillated fiber, the number of split fibers has a distribution in the length direction of the fiber.

[0037]

[Table 2]

As is apparent from Table 2, with respect to the felt-processed product, the collection efficiency is superior in the example, while the basis weight and the air permeability are almost the same as those in the example and the comparative example.
In addition, the example of the present invention is also excellent because the short fibers are separated from the cut surface. Furthermore, regarding materials for printed circuit boards,
The variation in the dielectric constant of the embodiment is smaller than that of the conventional material for printed circuit boards. In the case of a sheet-like material, a sheet-like material having lower elongation, better dimensional stability, and a more stable shape at the time of molding was obtained in the example than in the comparative example using an undrawn yarn.

[0039]

According to the present invention, the collecting effect, the toner sealing effect, and the like can be achieved without impairing the characteristics of the fluororesin fiber, such as heat resistance, chemical resistance, low dielectric constant and low coefficient of friction. Further, it is possible to provide a fluororesin-based fiber excellent in entanglement and dispersibility between constituent fibers, so that it is possible to provide a material particularly suitable for a toner sealing material, a filter material, and a material for a printed circuit board.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) D03D 15/00 D03D 15/00 A 4L047 D04B 1/16 D04B 1/16 4L048 D04H 1/42 D04H 1/42 N 4L055 D06C 11/00 D06C 11/00 A D21H 13/12 D21H 13/12 15/02 15/02 H05K 1/03 610 H05K 1/03 610T (72) Inventor Nobuhiro Hiroe Dojima Kita-ku, Osaka-shi, Osaka 1-6-20 Toray Fine Chemical Co., Ltd. (72) Inventor Iori Nakabayashi 1-1-1 Oe, Otsu-shi, Shiga Prefecture Toray Co., Ltd. Seta Plant F term (reference) 3B154 AA09 AA18 AB10 AB11 AB20 AB21 AB22 BA25 BB35 BB58 BB60 BF02 BF04 DA02 DA07 DA10 DA11 DA17 DA21 DA30 4D019 AA01 BA13 BB02 BB03 BB04 BB05 BC12 CA10 DA01 DA03 4L00 2 AA05 DA00 4L035 BB21 BB46 DD13 DD19 FF01 FF05 4L045 AA12 AA20 BA05 BA34 BA39 BA60 BB15 BB16 DA42 4L047 AA18 AB02 AB08 BA04 BA22 CA04 CB01 CB05 CB10 CC16 4L048 AA14 AA35 DA00 EB00 FA24 AF35 FA24 GA39

Claims (13)

[Claims] 1. A stretched single fiber having split fibers divided into a plurality of fibers, wherein the number of split fibers has a distribution in the length direction of the fibers, and A fluororesin-based fiber having a minimum fineness of 0.1 dtex or less. 2. When the number of split fibers of the fluororesin fiber is counted in the length direction of the fiber, the number of split fibers is from 1 to 65.
The fluororesin-based fiber according to claim 1, which is distributed between 00 fibers. 3. The method according to claim 1, wherein the fluororesin is polytetrafluoroethylene,
A resin comprising at least one selected from tetrafluoroethylene-hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkoxy group copolymer or tetrafluoroethylene-olefin copolymer The fluororesin-based fiber according to claim 1 or 2, wherein 4. A sheet-like material composed of a fiber base material, wherein the fibers constituting the fiber base material are stretched single fibers having split fibers divided into a plurality of fibers,
And a sheet-like article characterized in that the number of the split fibers has a distribution in the length direction of the fibers and that the split fibers include a fluororesin fiber having a minimum fineness of 0.1 dtex or less. . 5. The sheet according to claim 4, wherein the fluororesin fiber is contained in the sheet in an amount of 5% by weight or more. 6. The sheet according to claim 4, wherein the sheet is at least one selected from a woven fabric, a knitted fabric, a nonwoven fabric and a paper. 7. A sheet according to claim 6, wherein said paper comprises only drawn fluororesin fibers. 8. The sheet according to claim 4, wherein the sheet is for a filter material, a toner sealing material or a printed circuit board. 9. A fibril-forming fiber obtained by spinning by a matrix spinning method, an emulsion spinning method or a paste extruding method, firing, and then hot-drawing, by subjecting the fluororesin-based fired fiber to a water jet punch treatment. A method for producing a fluororesin fiber. 10. The water jet punching process has a water pressure of 4.9 × 10 ⁶ N / m ^{2 to} 19.6 × 10 ⁶ N / m ^2.
The method for producing a fluororesin fiber according to claim 9, wherein the treatment time is 5 to 20 seconds. 11. A method comprising spinning by matrix spinning, emulsion spinning or paste extrusion, firing, and then hot drawing to obtain a fibril by crushing or beating a fluororesin-based fiber. Of producing a fluororesin fiber. 12. A sheet made of a fibrous base material containing a fluororesin-based fiber obtained by spinning by a matrix spinning method, emulsion spinning method or paste extrusion method, followed by firing and then hot drawing, to form a water jet. Punch or crush or beat,
A method for producing a sheet-like material, comprising fibrillating the fluororesin fiber. 13. The water jet punching process, wherein the water pressure is 4.9 × 10 ⁶ N / m ^{2 to} 19.6 × 10 ⁶ N / m ^2.
The method according to claim 12, wherein the treatment time is 5 to 20 seconds.