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Patent US20060057350 - Nanofiber aggregate, polymer alloy fiber, hybrid fiber, fibrous structures ... - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inAdvanced Patent SearchPatentsThe present invention provides an aggregate of nanofibers having less spread of single fiber fineness values that can be used in wide applications without limitation to the shape and the kind of the polymer, and a method for manufacturing the same. The present invention is an aggregate of nanofibers...http://www.google.com/patents/US20060057350?utm_source=gb-gplus-sharePatent US20060057350 - Nanofiber aggregate, polymer alloy fiber, hybrid fiber, fibrous structures, and processes for production of themAdvanced Patent SearchPublication numberUS20060057350 A1Publication typeApplicationApplication numberUS 10/532,082PCT numberPCT/JP2003/013477Publication dateMar 16, 2006Filing dateOct 22, 2003Priority dateOct 23, 2002Also published asEP1564315A1, EP1564315A4, EP1564315B1, US8460790, US20110183563, WO2004038073A1Publication number10532082, 532082, PCT/2003/13477, PCT/JP/2003/013477, PCT/JP/2003/13477, PCT/JP/3/013477, PCT/JP/3/13477, PCT/JP2003/013477, PCT/JP2003/13477, PCT/JP2003013477, PCT/JP200313477, PCT/JP3/013477, PCT/JP3/13477, PCT/JP3013477, PCT/JP313477, US 2006/0057350 A1, US 2006/057350 A1, US 20060057350 A1, US 20060057350A1, US 2006057350 A1, US 2006057350A1, US-A1-20060057350, US-A1-2006057350, US2006/0057350A1, US2006/057350A1, US20060057350 A1, US20060057350A1, US2006057350 A1, US2006057350A1InventorsTakashi Ochi, Akira Kishiro, Shuichi NonakaOriginal AssigneeTakashi Ochi, Akira Kishiro, Shuichi NonakaExport CitationBiBTeX, EndNote, RefManPatent Citations (14), Non-Patent Citations (1), Referenced by (76), Classifications (45), Legal Events (1) External Links: USPTO, USPTO Assignment, EspacenetNanofiber aggregate, polymer alloy fiber, hybrid fiber, fibrous structures, and processes for production of them
US 20060057350 A1Abstract
The present invention provides an aggregate of nanofibers having less spread of single fiber fineness values that can be used in wide applications without limitation to the shape and the kind of the polymer, and a method for manufacturing the same. The present invention is an aggregate of nanofibers made of a thermoplastic polymer having single fiber fineness by number average in a range from 1�10−7 to 2�10−4 dtex and single fibers of 60% or more in fineness ratio have single fiber fineness in a range from 1�10−7 to 2�10−4 dtex. Images(17) Claims(39)
1. An aggregate of nanofibers made of a thermoplastic polymer, wherein single fiber fineness by number average is in a range from 1�10−7 to 2�10−4 dtex and 60%, in fineness ratio, or more of single fibers are in a range from 1�10−7 to 2�10−4 dtex in single fiber fineness. 3. (canceled) 4. The aggregate of nanofibers according to claim 1, wherein 50%, in fineness ratio, or more of single fibers that constitute the aggregate of nanofibers are in a section having a width of 30 nm in diameter of the single fibers. 5-6. (canceled) 7. The aggregate of nanofibers according to claim 1, wherein the thermoplastic polymer comprises one selected from among polyester, polyamide and polyolefin. 8. The aggregate of nanofibers according to claim 1, that has a strength of 1 cN/dtex or higher. 9. (canceled) 10. The aggregate of nanofibers according to claim 1, that has a rate of elongation at absorbing water of 5% or higher in the longitudinal direction of the yarn. 11. The aggregate of nanofibers according to claim 1, that contains a functional chemical agent. 12. A fibrous material that includes the aggregate of nanofibers according to claim 1. 13. (canceled) 14. The fibrous material according to claim 12, wherein the aggregate of nanofibers is encapsulated in a hollow space of a hollow fiber. 15. The fibrous material according to claim 14, wherein the hollow fiber has multitude of pores measuring 100 nm or less in diameter in the longitudinal direction. 16. The fibrous material according to claim 12, that contains a functional chemical agent. 17. The fibrous material according to claim 12, wherein the fibrous material is selected from among yarns, a wad of cut fibers, package, woven fabric, knitted fabric, felt, nonwoven fabric, synthetic leather and sheet. 18. The fibrous material according to 17, wherein the fibrous material is a laminated nonwoven fabric made by stacking a sheet of nonwoven fabric that includes the aggregate of nanofibers and a sheet of other nonwoven fabric. 19. The fibrous material according to claim 12, wherein the fibrous material is a fibrous article selected from among clothing, clothing materials, products for interior, products for vehicle interior, livingwares, environment-related materials, industrial materials, IT components and medical devices. 20. A liquid containing the aggregate of nanofibers according to claim 1 dispersed therein. 21. A polymer alloy fiber that has islands-in-sea structure consisting of two or more kinds of organic polymers of different levels of solubility, wherein the island component is made of a low solubility polymer and the sea component is made of a high solubility polymer, while the diameter of the island domains by number average is in a range from 1 to 150 nm, 60% or more of the island domains in area ratio have sizes in a range from 1 to 150 nm in diameter, and the island components are dispersed in linear configuration. 22. (canceled) 23. The polymer alloy fiber according to claim 21, wherein, among the island domains included in the polymer alloy fiber, 60%, in area ratio, or more of the island domains are in a section having a width of 30 nm in diameter of the island domains. 24. The polymer alloy fiber according to claim 21, wherein the content of the island component is in a range from 10 to 50% by weight of the entire fiber. 25-26. (canceled) 27. A polymer alloy fiber that is a conjugated fiber comprising the polymer alloy according to claim 21 and another polymer that are conjugated together. 28. The polymer alloy fiber according to claim 21, wherein the value of CR that is a measure of crimping characteristic is 20% or more, or the number of crimps is five per 25 mm or more. 29. The polymer alloy fiber according to claim 21, that has Uster unevenness is 5% or less. 30. The polymer alloy fiber according to claim 21, that has a strength of 1.0 cN/dtex or higher. 31. A fibrous material that includes the polymer alloy fiber according to claim 21. 32. The fibrous material according to claim 31, wherein the fibrous material is selected from among yarns, a wad of cut fibers, package, woven fabric, knitted fabric, felt, nonwoven fabric, synthetic leather and sheet. 33. The fibrous material according to claim 31, that includes the polymer alloy fibers and other fibers. 34. The fibrous material according to claim 31, wherein the fibrous material is a fibrous article selected from among clothing, clothing materials, products for interior, products for vehicle interior, livingwares, environment-related materials, industrial materials, IT components and medical devices. 35-38. (canceled) 39. A polymer alloy pellet that has islands-in-sea structure comprising two kinds of organic polymers of different levels of solubility, wherein the island component is made of a low solubility polymer and the sea component is made of a high solubility polymer, while melt viscosity of the high solubility polymer is 100 Pa.s or lower, or difference in melting point between the high solubility polymer and the low solubility polymer is in a range from −20 to +20� C. 40. An organic/inorganic hybrid fiber that includes the aggregate of nanofibers according to claim 1 in a proportion of 5 to 95% by weight, wherein at least part of the inorganic material exists within the aggregate of nanofibers. 41. A fibrous material that includes the organic/inorganic hybrid fiber according to claim 40. 42-45. (canceled) 46. A porous fiber wherein 90% by weight or more of the composition consists of an inorganic material, while multitude of pores are provided in the longitudinal direction and mean pore diameter of the pores in the cross section in the minor axis direction is in a range from 1 to 100 nm. 47. A fibrous material that includes the porous fibers according to claim 46. 48-51. (canceled)
TECHNICAL FIELD [0001] The present invention relates to an aggregate of nanofibers. It also relates to a polymer alloy fiber that serves as a precursor for the aggregate of nanofibers. Further it relates to a hybrid fiber and a fibrous material that include the aggregate of nanofibers. The present invention also includes a method for manufacturing the aforementioned articles. BACKGROUND ART [0002] Polymers manufactured through polycondensation such as polyester typified by polyethylene terephthalate (hereinafter abbreviated as PET) and polybutylene terephthalate (hereinafter abbreviated as PBT), and polyamide typified by nylon 6 (hereinafter abbreviated as N6) and nylon 66 (hereinafter abbreviated as N66) have been preferably used-in such applications as clothes and industrial materials, because of the favorable mechanical properties and heat resistance of these fibers. Polymers manufactured through addition polymerization typified by polyethylene (hereinafter abbreviated as PE) and polypropylene (hereinafter abbreviated as PP), in contrast, have been preferably used mainly in industrial applications, because of the favorable mechanical properties, resistance to chemicals and lightness of these fibers. [0003] The polyester fiber and the polyimide fiber, in particular, have been used in the applications for clothes and therefore have been subjected to vigorous researches for not only to modify the polymer but also to improve the properties by controlling the cross sectional shape of the fiber or using an extremely fine fiber. One of such attempts resulted in ultrafine polyester fibers made by using an islands-in-sea multi-component fiber, that was used in an epoch making new product of synthetic leather having the touch of suede. These ultrafine fibers have been applied to the manufacture of ordinary clothes, and are used in the development of clothes that have excellent hands like peach skin which can never be obtained with ordinary fibers. The ultrafine fibers, those have found applications not only for clothes but also for livingwares such as wiping cloth and industrial materials, have secured a position of its own in the area of synthetic fibers today. [0004] Recently, in particular, applications of the ultrafine fibers have been expanded to texturing cloth for the surface of a computer hard disk as described in Japanese Unexamined Patent Publication No. 2001-1252, and medical supplies such as cell adsorbing material as described in Japanese Unexamined Patent Publication No. 2002-172163. [0005] Accordingly, there has been demand for further finer fibers in order to make a synthetic leather of higher quality and clothes of excellent feeling. In the meantime, to increase the storage capacity of a hard disk with increased recording density, it is necessary to make the surface of the hard disk smoother from the mean surface roughness of 1 nm or more at the present to 0.5 nm or less. For this purpose, nanofibers having further decreased thickness have been required to make a texturing cloth for texturing the hard disk surface. [0006] In medical applications, too, nanofibers having the same size as the fibers that constitute living organs have been in demand in order to improve the affinity with the living cells. [0007] However, the present islands-in-sea multi-component spinning technology has a limitation of 0.04 dtex (equivalent diameter 2 μm) for improving the single fiber fineness, which cannot fully meet the needs for the nanofibers. While methods for making ultrafine fibers from polymer blend fibers are disclosed in Japanese Unexamined Patent Publication No. 3-113082 and in Japanese Unexamined Patent Publication No. 6-272114, a single fiber fineness that can be achieved by these technologies is 0.001 dtex (equivalent diameter 0.4 μm) at the best, which also cannot fully meet the needs for the nanofibers. [0008] A method for making an ultrafine fiber from polymer blend fibers using a static mixer is disclosed in U.S. Pat. No. 4,686,074. The ultrafine fibers manufactured by this technology were also not fine enough to meet the needs for the nanofibers. [0009] Meanwhile a technology called the electrospinning has been in spotlight as a promising technology that can manufacture ultrafine fibers. The electrospinning is a process in which a polymer is dissolved in an electrolysis solution and is extruded through a spinneret while applying a high voltage in a range from several thousands of volts to thirty kilovolts to the polymer solution, so as to generate a high speed jet of the polymer solution that subsequently deflects and expands, thereby producing the ultrafine fibers. This technology may produce, depending on the circumstance, yarns having a single fiber fineness on the order of 10−5 dtex (equivalent single fiber diameter several tens of nanometers), that is one hundredth or less in fineness and one tenth or less in diameter of the yarn produced by the conventional polymer blending technology. While this technology is mainly applied to bio-polymer such as collagen and water-soluble polymer, electrospinning may also be applied to thermoplastic polymer that is dissolved in an organic solvent. However, as is pointed out in Polymer, vol.40, 4585 (1999), the strings that constitute the ultrafine fibers are often connected by beads (about 0.5 μm in diameter) that is formed from a stagnant polymer drop, thus resulting in a large spread of single fiber fineness values in an aggregate of ultrafine fibers. Although attempts have been made to suppress the generation of the beads so as to generate a fiber of uniform diameter, there still remains a significant spread of single fiber fineness values (Polymer, Vol. 43, 4403 (2002)). Also because the form of the aggregate of fibers obtained by the electrospinning is limited to nonwoven fabric and the aggregate of fibers obtained is not oriented and not crystallized, in many cases, having far less strength compared to ordinary fibrous articles, there has been a limitation to the application of the technology. Moreover, there have been such problems that sizes of the fibrous articles manufactured by the electrospinning process are limited to about 100 cm2 at the most, and productivity is as low as several grams per hour at the best that is far lower than with the ordinary melt spinning processes. Furthermore, requirement for the application of a high voltage and the tendency of the organic solvent and the ultrafine fibers to be suspended in air were additional problems. [0010] An atypical method for manufacturing nanofibers is disclosed in Science, Vol. 285, 2113 (1999), according to which a polymerization catalyst is supported on a meso-porous silica so as to polymerize PE thereon, thereby to produce PE nanofiber chips measuring 30 to 50 nm (equivalent to 5�10−6 dtex to 2�10−5 dtex) in diameter. However, what can be obtained with this method is mere wad-like aggregate of nanofibers, which makes it impossible to draw a fiber therefrom. Also the polymer that can be processed with this method is limited to PE manufactured through addition polymerization. Polymers manufactured through polycondensation such as polyester and polyamide require dehydration in the process of polymerization, and there is a fundamental difficulty for applying the method to these fibers. Thus there has been a significant hurdle for practical application of the nanofibers obtained by this method. DISCLOSURE OF THE INVENTION [0011] The present invention provides an aggregate of nanofibers having less spread of single fiber fineness values that can be used in wide applications without limitation to the shape and the kind of the polymer, and a method for manufacturing the same. [0012] The present invention encompasses the following constitutions. (1) An aggregate of nanofibers made of a thermoplastic polymer, wherein single fiber fineness by number average is in a range from 1�10−7 to 2�10−4 dtex and single fibers of 60%, in fineness ratio, or more of single fibers are in a range from 1�10−7 to 2�10−4 dtex in single fiber fineness. (2) The aggregate of nanofibers according to (1), having a morphology like filament-yarn and/or a morphology like spun yarn. (3) The aggregate of nanofibers according to (1) or (2), wherein the single fiber fineness by number average is in a range from 1�10−7 to 1�10−4 dtex and single fibers of 60%, in fineness ratio, or more of single fibers are in a range from 1�10−7 to 1�10−4 dtex in single fiber fineness. (4) The aggregate of nanofibers according to any one of (1) to (3), wherein single fibers of 50%, in fineness ratio, or more of the single fibers that constitute the aggregate of nanofibers are in a section having a width of 30 nm in diameter of the single fibers. (5) The aggregate of nanofibers according to any one of (1) to (4), wherein the thermoplastic polymer comprises a polymer made through polycondensation. (6) The aggregate of nanofibers according to any one of (1) to (5), wherein the thermoplastic polymer has a melting point of 160� C. or higher. (7) The aggregate of nanofibers according to any one of (1) to (6), wherein the thermoplastic polymer comprises one selected from among polyester, polyamide and polyolefin. (8) The aggregate of nanofibers according to any one of (1) to (7), that has a strength of 1 cN/dtex or higher. (9) The aggregate of nanofibers according to any one of (1) to (8), that has a ratio of moisture adsorption of 4% or higher. (10) The aggregate of nanofibers according to any one of (1) to (9), that has a rate of elongation at absorbing water of 5% or higher in the longitudinal direction of the yarn. (11) The aggregate of nanofibers according to any one of (1) to (10), that contains a functional chemical agent. (12) A fibrous material that includes the aggregate of nanofibers according to any one of (1) to (11). (13) The fibrous material according to (12), wherein a mass per unit area of the fiber is in a range from 20 to 2000 g/m2. (14) The fibrous material according to (12) or (13), wherein the aggregate of nanofibers is encapsulated in a hollow space of a hollow fiber. (15) The fibrous material according to (14), wherein the hollow fiber has multitude of pores measuring 100 nm or less in diameter in the longitudinal direction. (16) The fibrous material according to any one of (12) to (15), that contains a functional chemical agent. (17) The fibrous material according to any one of (12) to (16), wherein the fibrous material is selected from among yarns, a wad of cut fibers, package, woven fabric, knitted fabric, felt, nonwoven fabric, synthetic leather and sheet. (18) The fibrous material according to (17), wherein the fibrous material is a laminated nonwoven fabric made by stacking a sheet of nonwoven fabric that includes the aggregate of nanofibers and a sheet of other nonwoven fabric. (19) The fibrous material according to any one of (12) to (18), wherein the fibrous material is a fibrous article selected from among clothing, clothing materials, products for interior, products for vehicle interior, livingwares, environment-related materials, industrial materials, IT components and medical devices. (20) A liquid containing the aggregate of nanofibers according to any one of (1) to (11) dispersed therein. (21) A polymer alloy fiber that has islands-in-sea structure consisting of two or more kinds of organic polymers of different levels of solubility, wherein the island component is made of a low solubility polymer and the sea component is made of a high solubility polymer, a diameter of the island domains by number average is in a range from 1 to 150 nm, 60% or more of the island domains in area ratio have sizes in a range from 1 to 150 nm in diameter, and the island components are distributed in linear configuration. (22) The polymer alloy fiber according to (21), wherein a diameter of the island domains by number average is in a range from 1 to 100 nm and 60%, in area ratio, or more of the island domains are in a range from 1 to 100 nm in diameter of the island domains. (23) The polymer alloy fiber according to (21) or (22), wherein, among the island domains included in the polymer alloy fiber, 60%, in area ratio, or more of the island domains are in a section having a width of 30 nm in diameter of the island domains. (24) The polymer alloy fiber according to any one of (21) to (23), wherein the content of the island component is in a range from 10 to 30% by weight of the entire fiber. (25) The polymer alloy fiber according to any one of (21) to (24), wherein the sea component is made of a polymer that is highly soluble to aqueous alkaline solution or hot water. (26) The polymer alloy fiber according to any one of (21) to (25), wherein the island component has a melting point of 160� C. or higher. (27) A polymer alloy fiber that is a conjugated fiber of the polymer alloy according to any one of (21) to (26) and another polymer that are conjugated together. (28) The polymer alloy fiber according to any one of (21) to (27), wherein the value of CR that is a measure of crimping characteristic is 20% or more, and the number of crimps is five per 25 mm or more. (29) The polymer alloy fiber according to any one of (21) to (28), wherein Uster unevenness is 5% or less. (30) The polymer alloy fiber according to any one of (21) to (29), that has a strength of 1.0 cN/dtex or higher. (31) A fibrous material that includes the polymer alloy fiber according to any one of (21) to (30). (32) The fibrous material according to (31), wherein the fibrous material is selected from among yarns, wad of cut fibers, package, woven fabric, knitted fabric, felt, nonwoven fabric, synthetic leather and sheet. (33) The fibrous material according to (31) or (32), that includes the polymer alloy fibers and other fibers. (34) The fibrous material according to any one of (31) to (33), wherein the fibrous material is a fibrous article selected from among clothing, clothing materials, products for interior, products for vehicle interior, livingwares, environment-related materials, industrial materials, IT components and medical devices. (35) A method for manufacturing a polymer alloy fiber through melt spinning of a polymer alloy that is made by melt blending of a low solubility polymer and a high solubility polymer, wherein the following conditions (1) to (3) are satisfied: [0048] (1) the low solubility polymer and the high solubility polymer that have been weighed independently are fed separately into a kneader and are blended under molten condition; [0049] (2) the content of the low solubility polymer in the polymer alloy is in a range from 10 to 50% by weight; and [0050] (3) the melt viscosity of the high solubility polymer is 100 Pa.s or lower, or difference in melting point between the high solubility polymer and the low solubility polymer is in a range from −20 to +20� C. (36) The method for manufacturing a polymer alloy fiber according to (35), wherein melt blending is carried out in a twin-screw extrusion-kneader and length of the kneading section of the twin-screw extrusion-kneader is from 20 to 40% of the effective length of a screw. (37) The method for manufacturing a polymer alloy fiber according to (35), wherein melt blending is carried out in a static mixer and the number of splits carried out in the static mixer is 1�106or more. (38) The method for manufacturing a polymer alloy fiber according to any one of (35) to (37), wherein shear stress generated between a spinneret orifice wall and the polymer by the melt spinning operation is 0.2 MPa or less. (39) A polymer alloy pellet that has islands-in-sea structure comprising two kinds of organic polymers of different levels of solubility, wherein the island component is made of a low solubility polymer and the sea component is made of a high solubility polymer, while melt viscosity of the high solubility polymer is 100 Pa.s or lower, or difference in melting point between the high solubility polymer and the low solubility polymer is in a range from −20 to +20� C. (40) An organic/inorganic hybrid fiber that includes the aggregate of nanofibers according to any one of (1) to (11) in a proportion of 5 to 95% by weight, wherein at least part of the inorganic material exists within the aggregate of nanofibers. (41) A fibrous material that includes the organic/inorganic hybrid fiber according to (40). (42) A method for manufacturing the organic/inorganic hybrid fiber according to (40), wherein the aggregate of nanofibers is impregnated with an inorganic monomer and subsequently the inorganic monomer is polymerized. (43) A method for manufacturing the fibrous material according to (41), wherein the fibrous material that includes the aggregate of nanofibers is impregnated with an inorganic monomer and subsequently the inorganic monomer is polymerized. (44) A method for manufacturing a hybrid fiber, wherein the aggregate of nanofibers according to any one of (1) to (11) is impregnated with an organic monomer and subsequently the organic monomer is polymerized. (45) A method for manufacturing a fibrous material, wherein the fibrous material according to any one of (12) to (19) above is impregnated with an organic monomer and subsequently the organic monomer is polymerized. (46) A porous fiber wherein 90% by weight or more of the composition consists of an inorganic material, while multitude of pores are provided in the longitudinal direction and mean pore diameter of the pores in the cross section in the minor axis direction is in a range from 1 to 100 nm. (47) A fibrous material that includes the porous fibers according to (46). (48) A method for manufacturing the porous fiber, wherein nanofibers are removed from the organic/inorganic hybrid fiber, that is made by impregnating the aggregate of nanofibers with an inorganic monomer and subsequently polymerizing the inorganic monomer, thereby to obtain the porous fiber according to (46). (49) A method for manufacturing a fibrous material, wherein nanofibers are removed from a material that includes the organic/inorganic hybrid fiber, which is made by impregnating the fibrous material that includes the aggregate of nanofibers with an inorganic monomer and then polymerizing the inorganic monomer, thereby to obtain the fibrous material according to (47). (50) A method for manufacturing a nonwoven fabric, wherein the polymer alloy fibers according to any one of (21) to (30) are cut into fiber chips 10 mm or less in length, then the high solubility polymer is dissolved and papered without drying. (51) A method for manufacturing a nonwoven fabric, wherein, after forming a nonwoven fabric or a felt that includes the polymer alloy fibers according to any one of (21) to (30), the nonwoven fabric or the felt and a base fabric made of a low solubility polymer are bonded together, and then the high solubility polymer is dissolved. BRIEF DESCRIPTION OF THE DRAWINGS [0067] FIG. 1 is a TEM micrograph showing a cross section of fibers of an aggregate of nylon nanofibers according to Example 1 of the present invention. [0068] FIG. 2 is a TEM micrograph showing a cross section of polymer alloy fibers according to Example 1 of the present invention. [0069] FIG. 3 is an SEM micrograph showing the state of side view of fibers of an aggregate of nanofibers according to Example 1 of the present invention. [0070] FIG. 4 is an optical micrograph showing the state of side view of fibers of the aggregate of nanofibers according to Example 1 of the present invention. [0071] FIG. 5 is a graph showing the spread of single fiber fineness values of the nanofibers according to Example 1 of the present invention. [0072] FIG. 6 is a graph showing the spread of single fiber fineness values of the nanofibers according to Example 1 of the present invention. [0073] FIG. 7 is a graph showing the spread of single fiber fineness values of ultrafine fibers according to Comparative Example 4. [0074] FIG. 8 is a graph showing the spread of single fiber fineness values of the ultrafine fibers according to Comparative Example 4. [0075] FIG. 9 is a graph showing the spread of single fiber fineness values of ultrafine fibers according to Comparative Example 5. [0076] FIG. 10 is a graph showing the spread of single fiber fineness values of the ultrafine fibers according to Comparative Example 5 [0077] FIG. 11 is a graph showing reversible elongation/contraction at absorbing water in Example 1 of the present invention. [0078] FIG. 12 is a diagram showing a spinning machine. [0079] FIG. 13 is a diagram showing a spinneret. [0080] FIG. 14 is a diagram showing a drawing machine. [0081] FIG. 15 is a diagram showing a spinning machine. [0082] FIG. 16 is a diagram showing a spinning machine. [0083] FIG. 17 is a diagram showing a spinning machine. [0084] FIG. 18 is a diagram showing a spun bond spinning machine. [0085] FIG. 19 is a graph showing an ammonia removing ratio. [0086] FIG. 20 is a graph showing a formaldehyde removing ratio. [0087] FIG. 21 is a graph showing a toluene removing ratio. [0088] FIG. 22 is a graph showing a hydrogen sulfide removing ratio.
DESCRIPTION OF REFERENCE NUMERALS [0000] 1: hopper 2: melting section 3: spin block 4: spinning pack 5: spinneret 6: cooling equipment 7: line of thread 8: thread-collecting finishing guide 9: first take-up roller 10: second take-up roller 11: wound yarn 12: weighing section 13: orifice length 14: orifice diameter 15: undrawn yarn 16: feed roller 17: first hot roller 18: second hot roller 19: third roller (room temperature) 20: drawn yarn 21: single-screw extrusion-kneader 22: static mixer 23: twin-screw extrusion-kneader 24: chip weighing machine 25: blending tank 26: ejector 27: fiber separating plate 28: separated line of thread 29: collector BEST MODE FOR CARRYING OUT THE INVENTION [0118] Thermoplastic polymers that can be preferably used for the manufacture of the aggregate of nanofibers of the present invention include polyester, polyamide, polyolefin, polyphenylene sulfide and the like. Among these, polycondensation polymers typified by polyester and polyamide are preferable because many thereof have high melting points. The polymer has a melting point of preferably 160� C. or higher which renders the nanofiber satisfactory heat resistance. For example, the melting point of polylactic acid (hereinafter abbreviated as PLA) is 170� C., that of PET is 255� C., and that of N6 is 220� C. The polymer may include particles, flame retarding agent, antistatic agent or the like added thereto. The polymer may also be copolymerized with other component to such an extent that the property of the polymer is not compromised. [0119] The nanofiber referred to in the present invention is a fiber having single fiber diameter in a range from 1 to 250 nm. An aggregate of such fibers is called the aggregate of nanofibers. [0120] According to the present invention, a mean value and spread of single fiber fineness values in the aggregate of nanofibers are important factors. A single fiber diameter is measured for 300 or more single fibers that are randomly sampled in the same cross section, through observation of the cross section of the aggregate of nanofibers with a transmission electron microscope (TEM). An example of the micrograph of the cross section of the nanofiber of the present invention is shown in FIG. 1. This measurement is made in at least five places, so as to measure the diameters of 1500 or more single fibers in all, thereby to determine the mean value and spread of single fiber fineness values in the aggregate of nanofibers. Positions to make these measurements are preferably separated by a distance of 10 m or more from each other, in order to ensure the uniformity of the fibrous article to be made from the aggregate of nanofibers. [0121] Mean value of the single fiber fineness is determined as follows. Fineness is calculated from the measured diameter of the single fiber and the density of the polymer that constitutes the single fiber, and these values are averaged. This mean value is referred to as “the single fiber fineness by number average” in the present invention. The value of density commonly used for the polymer is used in the calculation. According to the present invention, it is important that the single fiber fineness by number average is in a range from 1�10−7 to 2�10−4 dtex (equivalent to single fiber diameter from 1 to 150 nm). This is as thin as 1/100 to 1/100000 that of the ultrafine fiber made from the conventional islands-in-sea multi-component fiber, and enables it to make fabric for clothing that has touch feeling completely different from that of the ultrafine fibers of the prior art. When used as a texturing cloth for hard disk, it can make the hard disk surface far smoother than in the prior art. The single fiber fine