Method for producing fiber, method for producing non-woven fabric, and non-woven fabric

Abstract

A non-woven fabric containing fibers, the non-woven fabric containing the following component A and component B inside the fibers, the non-woven fabric containing the component A in an amount of 50-95% by mass and the component B in an amount of 5-50% by mass with respect to the mass of the entire non-woven fabric, the number-average fiber diameter of the fibers contained in the non-woven fabric being 4 [mu] m or less, and the number-average fiber diameter of the fibers contained in the non-woven fabric being 4 [mu] m or less. The sheet width of the non-woven fabric is 50 mm or more. Wherein component A: a thermoplastic resin having a curing point of 100 DEG C or less; component B: a compound having a curing point higher than the curing point of the resin having the highest curing point among the thermoplastic resins and having a melting point of less than 150 DEG C.

Description

Technical Field

[0001] The present invention relates to nonwoven fabrics. Background Art

[0002] Low melting point thermoplastic resins with a melting point below 100°C have a low processing temperature and require less equipment investment and energy consumption, so they have attracted much attention as fiber raw materials for nonwoven fabrics (for example, Patent Document 1).

[0003] In addition, several techniques for manufacturing nonwoven fabrics containing ultrafine fibers (for example, fiber diameter of 10 μm or less) using the above low melting point thermoplastic resins have been proposed (for example, Patent Documents 2 to 5). Ultrafine fibers are used in various situations such as filters, sanitary materials, battery separators, and medical materials. For example, they are being studied as support materials in the medical field.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-70207

[0007] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2020-169201

[0008] Patent Document 3: Japanese Patent Application Laid-Open No. 2013-520583

[0009] Patent Document 4: International Publication No. 2006 / 022430

[0010] Patent Document 5: Japanese Patent Application Laid-Open No. 10-500741 Summary of the Invention

[0011] The present invention provides a nonwoven fabric containing the following Component A and Component B inside the fibers.

[0012] Preferably, the above Component A is 50% by mass or more and 95% by mass or less based on the total mass of the nonwoven fabric.

[0013] Preferably, the above Component B is 5% by mass or more and 50% by mass or less based on the total mass of the nonwoven fabric.

[0014] The number average fiber diameter of the fibers contained in the above nonwoven fabric is preferably 4 μm or less.

[0015] The sheet width of the above nonwoven fabric preferably includes 50 mm or more.

[0016] Preferably, the above Component A is a thermoplastic resin having a curing point of 100°C or less.

[0017] Component B preferably contains a compound having a curing point higher than that of the resin having the highest curing point among the above thermoplastic resins and a melting point lower than 150°C.

[0018] In addition, the present invention provides a method for manufacturing fibers by spinning a thermoplastic resin composition containing Component A and Component B' described below.

[0019] Component A preferably contains a thermoplastic resin having a curing point of 100°C or lower.

[0020] Component B' preferably contains a compound having a curing point higher than that of the above thermoplastic resin and a melting point lower than the processing temperature.

[0021] With respect to the mass of the entire thermoplastic resin composition, the content of Component A is preferably 50% by mass or more and 95% by mass or less.

[0022] With respect to the mass of the entire thermoplastic resin composition, the content of Component B' is preferably 5% by mass or more and 50% by mass or less.

[0023] Preferably, there are steps (I) of heating and melting the above thermoplastic resin composition and step (II) of ejecting it from a nozzle.

[0024] Preferably, the above thermoplastic resin composition is spun with a fiber diameter of 4 μm or less.

[0025] The above and other features and advantages of the present invention will become clearer from the following description with appropriate reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a cross-sectional perspective view schematically showing an embodiment of the fiber constituting the non-woven fabric related to the present invention.

[0027] Figure 2 (A) of is a graph showing the results of DSC (cooling) for each of the thermoplastic resin of Component A, the compound of Component B, and the thermoplastic resin composition obtained by mixing the two in Example 1. (B) is a graph showing the relationship between their temperature and viscosity. (C) is a graph showing the relationship between their temperature and elastic modulus.

[0028] Figure 3 (A) of is a substitute photograph of the drawing showing the fiber state of the non-woven fabric sample obtained in Example 1. (B) is a graph showing the number distribution of its fiber diameter. (C) is a graph showing the volume distribution of its fiber diameter.

[0029] Figure 4 It is a substitute photograph of the drawing showing the state of the sample obtained in Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention relates to a method for producing a wide-width nonwoven fabric containing ultrafine fibers and the ultrafine fibers constituting the nonwoven fabric.

[0031] When producing ultrafine fibers using the above-mentioned low-melting thermoplastic resin, there are difficulties in productivity with existing technologies, and industrialization is practically impossible. Specifically, in the electrospinning method (melt method, solution method) or meltblowing method to make the fibers thinner, there is usually a restriction that the discharge amount from the nozzle has to be suppressed and spinning has to be slow.

[0032] Moreover, the low-melting thermoplastic resin is also likely to maintain its fluidity after being discharged from the nozzle in a molten state or a solution state. Therefore, there are cases where it exhibits liquid behavior and is insufficiently stretched, or it is welded in a state of insufficient cooling and becomes an aggregate. As a result, lumps (shots) or broken fibers (fly-like substances) are likely to occur, and it is difficult to stably form fibers with good productivity. Therefore, it is necessary to further reduce the discharge amount, inevitably making the spinning speed extremely slow. For example, it has to be set at a low speed of about 1 / 100 to 1 / 1000 of the spinning speed generally required in industrial production in the production line, with the discharge amount per nozzle set at about 0.001 g / minute·nozzle.

[0033] Due to such an extreme suppression of the discharge amount, the industrial production of nonwoven fabrics of ultrafine fibers using a low-melting thermoplastic resin is difficult and limited to a small scale at the test piece level. Therefore, it is difficult to efficiently mass-produce a wide-width nonwoven fabric of ultrafine fibers with a desired width (for example, a high-quality nonwoven fabric with a sufficient width required for actual products such as filters) using existing production lines. From the perspective of industrial production, there is an urgent need to develop a wide-width nonwoven fabric composed of ultrafine fibers. Regarding this problem point and its solution, it is not disclosed in the above-mentioned Patent Documents 1 to 5.

[0034] The nonwoven fabric of the present invention is a wide-width nonwoven fabric containing ultrafine fibers. The ultrafine fibers constituting the above nonwoven fabric can be mass-produced efficiently by the fiber manufacturing method of the present invention.

[0035] Hereinafter, the nonwoven fabric of the present invention and the method for producing the fibers constituting the nonwoven fabric will be described.

[0036] The nonwoven fabric of the present invention preferably contains a thermoplastic resin with a curing point of 100°C or lower (hereinafter referred to as Component A) and a compound with a curing point higher than that of the thermoplastic resin and a melting point lower than 150°C (hereinafter referred to as Component B) inside the fibers.

[0037] Relative to the mass of the entire non-woven fabric of the present invention, it preferably contains 50% by mass or more and 95% by mass or less of the above-mentioned Component A and 5% by mass or more and 50% by mass or less of the above-mentioned Component B. The above-mentioned content ratios of Component A and Component B respectively refer to the ratios when the mass of the entire non-woven fabric of the present invention is 100% by mass.

[0038] (Method for measuring the curing point)

[0039] The above-mentioned "curing point" is also called the curing temperature, which refers to the peak temperature of the first exothermic peak when the sample is gradually heated and melted by differential scanning calorimetry (DSC) and then cooled at 5°C / min. The specific measurement is carried out as follows. First, the non-woven fabric is washed and dried with a solvent that does not dissolve the fibers, such as water. Then, a slice is cut out to make the mass 1 mg, and the constituent components to be measured are extracted. In the case where the non-woven fabric is assembled into a product, it is carried out after taking out the non-woven fabric by only peeling or cutting out this part. The extracted constituent components are sealed in an aluminum sample pan and heated, and gradually heated at 5°C / min. By heating, after the heating temperature reaches 200°C, it is gradually cooled at 5°C / min within 600 seconds. Then, the measurement is ended when the temperature reaches 0°C.

[0040] Among them, the above-mentioned peak temperature refers to the temperature at which the heated component starts to solidify from the molten state by cooling. The above-mentioned "molten state" refers to the state in which the above-mentioned component flows when an external force is applied, for example, it refers to the state of being heated above the melting point of the target component. The above-mentioned "solidification" refers to crystallization, and in the case where crystallization cannot be observed, it refers to glass transition.

[0041] (Method for measuring the content ratios of Component A and Component B)

[0042] The constituent components extracted by the extraction method of each constituent component shown in the above (Method for measuring the curing point) are dissolved in the deuterated solvents that are soluble in each of them, and each constituent component is identified using proton NMR. Thus, the constituent components corresponding to Component A and B are identified.

[0043] Then, the components are extracted from the fiber aggregate with a solvent that can dissolve the identified Component A or B, and thus their content ratios are obtained.

[0044] For example, the fiber aggregate is immersed in an organic solvent that can dissolve Component B for 24 hours to extract Component B. The fiber is taken out from the organic solvent and dried under reduced pressure at 40°C -0.04 MPa for 24 hours. Then, the weight of the dried fiber is measured, and thus the mass% of Component B can be measured.

[0045] Content ratio of Component B (% by mass) = 100 - (mass of fiber after reduced pressure drying / initial mass of fiber) × 100

[0046] For each of the above-identified constituent components, the fiber to be measured is measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS) to detect whether it can be detected within the fiber shape. If constituent components corresponding to Components A and B can be detected from within the fiber shape, it is determined that they are contained inside the fiber.

[0047] The mass content of Component A relative to the entire nonwoven fabric is 50% by mass or more and 95% by mass or less, and it is the main base agent of the constituent fibers of the nonwoven fabric of the present invention. Since the curing point of such a thermoplastic resin is 100°C or lower, a decrease in the viscosity and elasticity of the constituent fibers containing it as the main base agent occurs at a lower temperature. Thus, the nonwoven fabric of the present invention can reduce the temperature for bonding by embossing or the like and becomes a nonwoven fabric with high processability. In addition, it is easy to spin in the manufacturing method described later, and thermal bonding or the like can be performed at a low temperature, so energy consumption and equipment investment can be suppressed.

[0048] From the above viewpoints, the curing point of the thermoplastic resin contained in Component A is preferably 75°C or lower, more preferably 60°C or lower.

[0049] In addition, the curing point of the thermoplastic resin contained in Component A is actually 0°C or higher.

[0050] The melting point of the thermoplastic resin contained in Component A is preferably 150°C or lower, more preferably 120°C or lower, and further preferably 90°C or lower. Thereby, the temperature for bonding by embossing or the like can be reduced, and the processability becomes higher.

[0051] In addition, the above melting point is preferably 50°C or higher. Thereby, the shape stability in a high-temperature environment such as in summer is improved.

[0052] From the viewpoint of further enhancing the above effects, the content ratio of Component A relative to the mass of the entire nonwoven fabric is preferably set to 60% by mass or more, more preferably 65% by mass or more, and further preferably 70% by mass or more.

[0053] In addition, from the viewpoint of further enhancing the effects brought about by Component B described later, the content ratio of Component A relative to the mass of the entire nonwoven fabric is preferably set to 95% by mass or less, more preferably less than 90% by mass, and further preferably 85% by mass or less.

[0054] Component B can moderately increase the curing point of the constituent fibers of the non-woven fabric of the present invention from the curing point of Component A alone by having a curing point higher than that of the resin having the highest curing point among the thermoplastic resins contained in Component A and having a mass content of 5% by mass or more and 50% by mass or less based on the total mass of the non-woven fabric. In addition, in the manufacturing method described later, during the process of stretching and cooling the molten liquid of the thermoplastic resin composition (Component A + Component B) ejected from the nozzle, the compound contained in Component B is likely to cure earlier than the thermoplastic resin contained in Component A.

[0055] In addition, in the manufacturing method described later, as the entire thermoplastic resin composition, due to the moderate increase in the curing point, the reference temperature at which the viscosity and elastic modulus increase sharply from the molten state is also moderately increased compared to the case of Component A alone. As a result, the timing of curing after ejection becomes good. Moreover, Component A, which is the main base of the fiber, is stretched in a molten state, while Component B compensates for the strength of the extremely fine diameter of 4 μm or less, enabling good stretching and good fibrillation. In addition, since the melting point of Component B is lower than 150°C, Component B is likely to exist in a molten state in the molten liquid ejected from the nozzle under the processing temperature environment of the manufacturing method described later. As a result, in the manufacturing method described later, the mixing and melting property of Component B and Component A is improved, the occurrence of resin blocks with Component B as the core is suppressed, and nozzle clogging or fiber breakage is less likely to occur.

[0056] As a result, defects such as pores in the non-woven fabric of the present invention are reduced. In addition, the occurrence of lumps is suppressed, the fiber diameter is finer, and its uniformity is improved. Moreover, the non-woven fabric of the present invention has excellent tactile properties.

[0057] From the viewpoint of making the above effects better, the difference between the curing point of the compound contained in Component B and the curing point of the resin having the highest curing point among the thermoplastic resins contained in Component A is preferably 5°C or more.

[0058] In addition, from the viewpoint of suppressing excessive energy consumption, the difference is preferably 100°C or less, more preferably 60°C or less.

[0059] From the viewpoint of making the above effects better, the melting point of the compound contained in Component B is preferably lower than 150°C, more preferably 135°C or less, and further preferably 120°C or less.

[0060] In addition, from the viewpoint of facilitating the operation during raw material supply, the melting point of the compound contained in Component B is preferably 30°C or more, more preferably 40°C or more, and further preferably 50°C or more.

[0061] From the viewpoint of further improving the compatibility of component A and component B in the manufacturing method described below, the difference in melting point between the thermoplastic resin contained in component A and the compound contained in component B is preferably more than 0°C and 100°C or less, more preferably 60°C or less, and still more preferably 50°C or less, in the combination with the largest difference.

[0062] By setting it within this temperature range, kneading can be performed without overheating one of the raw materials, and kneading with sufficient compatibility time can be carried out.

[0063] From the viewpoint of further enhancing the above-described effect, the content ratio of component B relative to the total mass of the nonwoven fabric is preferably set to 10% by mass or more, more preferably more than 10% by mass.

[0064] In addition, the content ratio of component B relative to the total mass of the nonwoven fabric is preferably set to 40% by mass or less, more preferably 35% by mass or less, and still more preferably 30% by mass or less. By setting it below the above upper limit, it can be sufficiently compatible with component A by a melt kneader such as an extruder, and the above-described effect can be further enhanced.

[0065] The nonwoven fabric of the present invention can be manufactured into a good nonwoven fabric by using the manufacturing method described below, by including the above-described component A and component B as constituent components of the constituent fibers. As a result, the number average fiber diameter of the nonwoven fabric of the present invention is extremely fine, 4μm or less, and the sheet width is wide.

[0066] The number average fiber diameter refers to the fiber diameter measured by the following method, and represents the average fiber diameter of the entire constituent fibers of the nonwoven fabric of the present invention. From the viewpoint of making the skin feel of the nonwoven fabric softer and smoother, such a number average fiber diameter is preferably 3μm or less, more preferably 2μm or less.

[0067] In addition, from the viewpoint of maintaining fiber strength, the above number average fiber diameter is preferably 0.1μm or more, more preferably 0.2μm or more.

[0068] (Method for measuring the number average fiber diameter of the constituent fibers of the nonwoven fabric of the present invention)

[0069] From the two-dimensional image obtained by scanning electron microscope observation, 100 fibers are arbitrarily selected, excluding defects such as lumps of constituent fibers, cross-sections of constituent fibers, and polymer droplets, and the width orthogonal to the length direction (fiber length direction) of each fiber is measured. The sum of these values is divided by the number of fibers measured to obtain the number average fiber diameter of the nonwoven fabric to be measured. In addition, when the cross-section orthogonal to the length direction of the constituent fiber is not circular, the above fiber diameter is converted into an equivalent circle diameter.

[0070] In the non-woven fabric of the present invention, from the viewpoint of further improving the softness and smoothness of the skin feel, the median fiber diameter of the constituent fibers is preferably 2 μm or less, more preferably 1.5 μm or less, and still more preferably 1 μm or less.

[0071] In addition, from the viewpoint of maintaining fiber strength, the median fiber diameter of the constituent fibers is preferably 0.1 μm or more, more preferably 0.2 μm or more.

[0072] The median fiber diameter mentioned here refers to the fiber diameter at which the cumulative frequency is 50% (median value) of the whole in the frequency distribution (histogram) of the fiber diameters obtained by the above-described method for measuring the number-average fiber diameter.

[0073] In the non-woven fabric of the present invention, in addition to satisfying the above conditions for the number-average fiber diameter, the above conditions for the median fiber diameter are also satisfied. As a result, the number of finer fibers increases, and the cleaning and wiping property and the skin adhesion are improved.

[0074] In the non-woven fabric of the present invention, the above-mentioned "sheet width" refers to the length of the longest line segment connecting the outer connection lines through the center of the plane of the non-woven fabric of the present invention. For example, when the plane is a circle, it is the diameter; when it is an ellipse, it is the major axis. In the case of a quadrilateral, it is the length of the longest line segment among the lines passing through the center and connecting two opposite sides as described above. In the case of a square, it corresponds to the length of one side; in the case of a rectangle, it corresponds to the length of the long side. In the case of a planar shape such as a polygon that is not included in the above shapes, the equivalent circle diameter calculated from the area is regarded as the above sheet width. However, in the case of a continuous sheet, since the center of the plane is not determined, for convenience, the length in the width direction orthogonal to the length direction is taken as the sheet width.

[0075] Since the ejection amount from the nozzle of the non-woven fabric made of fibers having the same fiber diameter by the existing method is significantly low, it takes a long time to produce a sheet having a wide sheet width and is not practical. In contrast, since the constituent fibers of the non-woven fabric of the present invention contain the above-mentioned component A and component B, the above-mentioned extremely fine fiber diameter can be efficiently and rapidly formed in the manufacturing method described later, resulting in a non-woven fabric having an improved uniformity of the above-mentioned extremely fine fiber diameter and a larger area. The above-mentioned sheet width of the non-woven fabric of the present invention is preferably 50 mm or more, more preferably 100 mm or more, still more preferably 150 mm or more, still more preferably 200 mm or more, and still more preferably 300 mm or more.

[0076] In addition, the longer the above-mentioned sheet width is, the better. From the viewpoint of suppressing an increase in the width of the manufacturing apparatus, the upper limit is actually 3000 mm or less.

[0077] From the viewpoint of the dimensions required for the actual product, "sheet width" / "length orthogonal to the sheet width" is preferably 8 or less, more preferably 4 or less, still more preferably 2 or less, and particularly more preferably 1.5 or less.

[0078] Also from the viewpoint of the dimensions required for the actual product, "sheet width" / "length orthogonal to the sheet width" is actually 1 or more.

[0079] In the nonwoven fabric of the present invention, Component A may contain various thermoplastic resins having a curing point of 100°C or lower.

[0080] For example, Component A may contain one or more selected from polyolefin resins, polyester resins, aliphatic polyamide resins, vinyl-based polymer resins, acrylic-based polymer resins, polyvinyl acetate, polyvinyl acetate-ethylene copolymers, and polyether resins.

[0081] As the polyolefin resin, one or more selected from polyethylene, polypropylene, and ethylene-α-olefin copolymers may be contained.

[0082] As the polyester resin, one or more selected from aliphatic polyesters, semi-aromatic polyesters, polybutylene terephthalate, polylactic acid, polyhydroxyalkanoates, and liquid crystal polymers may be contained.

[0083] As the aliphatic polyester, one or more selected from polycaprolactone, polybutylene succinate, polybutylene succinate adipate, polyglycolic acid, and polydioxanone may be contained.

[0084] As the semi-aromatic polyester, one or more selected from polyethylene terephthalate and polybutylene terephthalate may be contained.

[0085] As the aliphatic polyamide resin, one or more selected from nylon 6 and nylon 66 may be contained.

[0086] As the vinyl-based polymer resin, one or more selected from polyvinyl chloride, polyvinylidene chloride, and polystyrene may be contained.

[0087] As the acrylic-based polymer resin, one or more selected from polyacrylic acid, polyacrylate, polymethacrylic acid, and polymethacrylate may be contained.

[0088] As the polyether resin, polyethylene oxide may be contained.

[0089] Among them, from the viewpoint of improving the compatibility with Component B, Component A preferably contains one or more selected from polyester resins and polyether resins.

[0090] The aliphatic polyester resin is preferably biodegradable. Thus, when the constituent fibers of the nonwoven fabric of the present invention flow out into the environment (for example, when the nonwoven fabric of the present invention is used as a cosmetic material and the fibers flow out during washing for reuse, etc.), the impact on the environment can be reduced. Herein, the "biodegradability" means that the biodegradation degree of the polyester measured according to JIS K6953-1 is 30% or more.

[0091] As the biodegradable aliphatic polyester resin, it is preferably composed of one or more selected from polycaprolactone (hereinafter also referred to as PCL), polybutylene succinate, polybutylene adipate succinate, polydioxanone, and polyglycolic acid.

[0092] As the biodegradable polyether resin, it is preferably composed of polyethylene oxide.

[0093] In addition, from the viewpoints of improving processability and biodegradability, it is more preferable to also contain PCL in the polyester resin.

[0094] In any of the above cases, as the resin having a curing point of 100°C or lower, it is preferably to satisfy the conditions of the weight-average molecular weight described below.

[0095] As the thermoplastic resin contained in Component A as the main base of the fiber, from the viewpoint of forming the nonwoven fabric of the present invention having the above-mentioned finer fiber diameter and larger area, the weight-average molecular weight is preferably 200,000 g / mol or less, more preferably 150,000 g / mol or less, and still more preferably 100,000 g / mol or less.

[0096] From the viewpoint of smoothly stretching in a molten state during spinning, the weight-average molecular weight of the thermoplastic resin contained in Component A is preferably 5,000 g / mol or more, more preferably 10,000 g / mol or more.

[0097] (Method for measuring weight-average molecular weight)

[0098] For Components A and B identified according to the above-mentioned (Method for measuring the content ratio of Components A and B), immerse the nonwoven fabric sheet to be measured in a solvent that dissolves only one of Components A and B, separate the solvent and the residue, and then dry it to separate Component A or Component B.

[0099] The molecular weight of Component B is determined by the measurement of the above-mentioned (Method for measuring the content ratio of Components A and B).

[0100] For the separated Component A, gel permeation chromatography was used to measure the weight-average molecular weight in terms of polystyrene under the following conditions. As polystyrene standard samples, polystyrene samples with known weight-average molecular weights and different weight-average molecular weights were used (for example, monodisperse polystyrene manufactured by Tosoh Corporation (model numbers: F450, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000, A500, and A300)). A molecular weight calibration curve was prepared in advance, and the results of this calibration curve were compared with those of the test sample to perform the measurement.

[0101] <Gel Permeation Chromatography Conditions>

[0102] · Measuring device: HLC-8220GPC (manufactured by Tosoh Corporation)

[0103] · Chromatographic column: GMHHR-H + GMHHR-H (manufactured by Tosoh Corporation)

[0104] · Eluent: 1 mmol FARMIN DM20 (manufactured by Kao Corporation) / CHCl3

[0105] · Eluent flow rate: 1.0 mL / min

[0106] · Column temperature: 40 °C

[0107] · Detector: RI

[0108] · Sample concentration: 0.1 vol% (chloroform solution)

[0109] · Sample injection volume: 100 mL

[0110] In the nonwoven fabric of the present invention, the compound contained in Component B preferably has a weight-average molecular weight of 1000 g / mol or less. By avoiding the use of polymers, the compatibility with the thermoplastic resin of Component A is improved.

[0111] The compound contained in Component B is actually 100 g / mol or more.

[0112] As the compound contained in Component B, various compounds can be used that have a solidification point higher than the solidification point of the resin with the highest solidification point among the thermoplastic resins contained in Component A and have a melting point lower than 150 °C.

[0113] For example, Component B may contain one or more selected from fatty acids, higher alcohols, fatty acid amide compounds, polyol organic acid ester compounds, waxes, sphingolipids, alkyl ammonium salts, and fatty acid metal salts.

[0114] As the fatty acid, for example, it may contain one or more selected from stearic acid, behenic acid, myristic acid, and palmitic acid.

[0115] As the higher alcohol, for example, it may contain one or more selected from cetyl alcohol, myristyl alcohol, and stearyl alcohol.

[0116] As the fatty acid amide compound, for example, it may contain one or more selected from stearic acid monoamide, oleic acid amide, erucic acid amide, and ethylene-bis-stearic acid amide.

[0117] As the polyol organic acid ester compound, for example, it may contain one or more selected from the ester compounds of polyol and fatty acid, the ester compounds of polyol and polycarboxylic acid, and the ester compounds of polyol and hydroxy acid.

[0118] The ester compound may be a monoester, a diester, or a triester.

[0119] As the polyol organic acid ester compound, for example, it may contain one or more selected from glycerol fatty acid ester compounds, polyglycerol fatty acid ester compounds, sucrose fatty acid ester compounds, and sorbitan fatty acid ester compounds.

[0120] As the glycerol fatty acid ester compound, for example, it may contain one or more selected from behenyl glyceride, stearic acid glyceride, and 12-hydroxy stearic acid glyceride.

[0121] As the polyglycerol fatty acid ester compound, for example, it may contain one or more selected from polyglycerol stearate and polyglycerol behenate.

[0122] As the sucrose fatty acid ester compound, for example, it may contain one or more selected from sucrose stearate compounds and sucrose behenate glyceride.

[0123] As the sorbitan fatty acid ester compound, for example, it may contain one or more selected from sorbitan distearate, sorbitan monostearate, and sorbitan tribehenate.

[0124] As the wax, for example, it may contain one or more selected from various plant-based waxes such as paraffin wax and carnauba wax.

[0125] As the sphingolipid, for example, it may contain one or more selected from ceramide, glycosphingolipid, and sphingomyelin.

[0126] As the alkylammonium salt, for example, it may contain one or more selected from distearyldimethylammonium chloride.

[0127] As the fatty acid metal salt, for example, it may contain one or more selected from zinc stearate, magnesium stearate, and calcium stearate.

[0128] Among the specific examples of the above compounds, as the compound satisfying the conditions of Component B, it preferably satisfies the above conditions of the weight-average molecular weight.

[0129] From the viewpoint of making it compatible with Component A, Component B preferably contains one or more selected from fatty acids, higher alcohols, fatty acid amide compounds, polyol organic acid ester compounds, waxes, and fatty acid metal salts.

[0130] In addition, from the viewpoint of further improving the compatibility between Component B and Component A, it is preferred that Component A contains a polar aliphatic polyester resin, and Component B contains one or more selected from fatty acids, higher alcohols, and ester compounds of polyols and fatty acids.

[0131] At this time, the above ester compound preferably has a skeleton in which carbon atoms are bonded to each other by single bonds, and more preferably the skeleton is a straight chain.

[0132] Among them, Component B is also more preferably one or more selected from stearic acid, behenic acid, myristyl alcohol, and glyceryl behenate. By selecting these components, a nonwoven fabric with a fine fiber diameter can be obtained.

[0133] Among the compounds contained in Component B, the compound having a salt structure, particularly a metal salt structure, is preferably 5% by mass or less, more preferably 3% by mass or less, and still more preferably 1% by mass or less. Thereby, it is possible to prevent the charge from propagating and escaping in Component B in the fiber during the electrostatic spinning process.

[0134] In addition, among the compounds contained in Component B, the compound having a salt structure, particularly a metal salt structure, is preferably more than 0% by mass, more preferably 0.5% by mass or more. Thereby, the electrostatic spinning treatment can be effectively carried out.

[0135] The "salt structure" mentioned here refers to a structure having a positive charge part and a negative charge part and ionizing when melted. For example, a structure having a positive charge part and a negative charge part in one molecule (also called zwitterion, intramolecular salt) and being in a neutral state as one molecule can be cited. In addition, it can also be a structure in which a salt is formed between multiple molecules of a cationic compound having a positive charge part in one molecule and an anionic compound having a negative charge part in one molecule.

[0136] In such a nonwoven fabric of the present invention, it is preferred that the core layer of the fiber formed by Component A extends in the length direction of the fiber (fiber length direction), and Component B is disposed on the fiber surface (i.e., the surface of the thermoplastic fiber). In this case, Component B exists inside the fiber and a part of it appears on the fiber surface side. In addition, Component B existing inside the fiber can be mixed with Component A.

[0137] In addition, asFigure 1 As in the case of the constituent fiber 1 shown, preferably, the component B covers the peripheral surface of the core layer 2 of the component A as the skin layer 3. At this time, the interface of the component concentration between the skin layer 3 of the component B and the core layer 2 of the component A does not necessarily have to be clear, and is preferably blurred. The skin layer 3 of the component B may cover the entire fiber surface or may cover it partially. In the case of partial coverage, it may be an island structure configuration in which a certain region of the skin layer 3 of the component B includes a region where the skin layer 3 of the component B is absent, or it may be a configuration in which there are regions where the skin layer 3 of the component B exists and regions where it does not exist.

[0138] The core layer 2 and the skin layer 3 can be formed as follows in the manufacturing method described later.

[0139] If the components A and B with different solidification points are spun, the higher the solidification point, the earlier it solidifies during spinning and thus becomes more stable. As an interface between air and the molten resin, a stable interface can be formed, so the component that is easily cured tends to appear on the air side. Therefore, although the components A and B are present inside the fiber, depending on the difference in solidification points, the core layer 2 and the skin layer 3 are also formed.

[0140] Next, a preferred embodiment of the manufacturing method of the fiber constituting the non-woven fabric of the present invention will be described.

[0141] The manufacturing method of the fiber of the present embodiment uses a thermoplastic resin composition. The thermoplastic resin composition preferably contains, based on the total mass thereof, 50% by mass or more and 95% by mass or less of a thermoplastic resin having a solidification point of 100°C or lower (hereinafter referred to as component A.); and 5% by mass or more and 50% by mass or less of a compound having a solidification point higher than the solidification point of the resin having the highest solidification point among the above thermoplastic resins and a melting point lower than the processing temperature (hereinafter referred to as component B'). Preferably, the steps of (I) heating and melting the thermoplastic resin composition and (II) ejecting it from a nozzle are performed. Thereby, it is preferable to spin the fiber with a fiber diameter of 4 μm or less. In addition, the component B' can be set to have the same properties as the component B shown in the non-woven fabric of the present invention described above, and may contain the compounds shown as specific examples of the component B.

[0142] In addition, the above "processing temperature" refers to the temperature of the heat applied in the manufacturing method of the present invention, mainly referring to the temperature heated for the heating and melting in the step (I). It also refers to the temperature of the heating fluid ejected in the step (II) described later. This processing temperature can be appropriately set according to the melting point of the resin having the highest melting point among the thermoplastic resins contained in the component A as the main base of the fiber. Considering the melting point of the component B', the above processing temperature is higher than the melting point of the resin having the highest melting point among the thermoplastic resins contained in the component A (for example, 20°C or more and 200°C or less higher than the melting point). For example, it is set to 150°C.

[0143] Component A preferably has a content ratio of 60% by mass or more, more preferably 65% by mass or more, and still more preferably 70% by mass or more, based on the total mass of the above thermoplastic resin composition.

[0144] In addition, component A preferably has a content ratio of 95% by mass or less, more preferably less than 90% by mass, and still more preferably 85% by mass or less, based on the total mass of the above thermoplastic resin composition.

[0145] Component B' preferably has a content ratio of 10% by mass or more, more preferably more than 10% by mass, based on the total mass of the above thermoplastic resin composition.

[0146] In addition, component B' preferably has a content ratio of 40% by mass or less, more preferably 35% by mass or less, and still more preferably 30% by mass or less, based on the total mass of the above thermoplastic resin composition.

[0147] Thereby, the effects of component A and component B' in the manufacturing method described in the above non-woven fabric related description can be further improved.

[0148] In the step (I) above, for example, component A and component B' are introduced into a housing connected to the hopper via the hopper. These component A and component B' are heated and melted in the housing to produce a molten liquid of the above thermoplastic resin composition (hereinafter, also simply referred to as a resin mixed molten liquid). The resin mixed molten liquid is extruded toward a nozzle for ejection by the rotation of a screw and supplied to an ejection port at the tip of the nozzle. The nozzle in this case can be one or multiple.

[0149] Next, in the step (II) above, the supplied resin mixed molten liquid is ejected from the nozzle for spinning. The ejected resin mixed molten liquid is stretched and cooled as it moves away from the ejection port at the tip of the nozzle and gradually solidifies into fibers. At this time, by appropriately setting the aperture diameter of the ejection port at the tip of the nozzle, fibers with a fiber diameter of 4 μm or less can be spun. In addition, as described above, since the resin mixed molten liquid of component A and component B is spun, even if the ejection speed is not set to a low speed at the level of the existing test piece production, but is carried out at a high speed (for example, 0.5 g / min to 5 g / min) industrially implemented in an actual production line, it is not easy to generate lumps (shots) and fiber breakage (fly-like substances). Thereby, it is possible to uniformly, efficiently, and stably fiberize into ultrafine fibers with a number average fiber diameter of 4 μm or less.

[0150] In the process of (II) above, the ejection speed of the molten liquid of the above thermoplastic resin composition from the nozzle is preferably set to 0.1 g / minute·nozzle or more, more preferably set to 0.2 g / minute·nozzle or more, and further preferably set to 0.5 g / minute·nozzle or more.

[0151] In addition, from the viewpoint of making the diameter of the spun fibers finer, the ejection speed of the molten liquid of the above thermoplastic resin composition from the nozzle is preferably set to 20 g / minute·nozzle or less, more preferably set to 10 g / minute·nozzle or less.

[0152] From the viewpoint of further improving the uniform spinning property at an extremely fine fiber diameter, the viscosity of the resin mixed molten liquid at the time of nozzle ejection is preferably 1 Pa·s or more, more preferably 2 Pa·s or more, and further preferably 5 Pa·s or more.

[0153] In addition, from the viewpoint of easily reducing the viscosity to make the fibers finer, the viscosity of the resin mixed molten liquid at the time of nozzle ejection is preferably 40 Pa·s or less, more preferably 20 Pa·s or less, and further preferably 15 Pa·s or less.

[0154] (Method for measuring the viscosity of the resin mixed molten liquid)

[0155] The measurement of the melt viscosity is carried out using a rotational rheometer. Specifically, the measurement is carried out using an MCR305 device manufactured by Anton Paar GmbH. The measuring fixture uses parallel plates, and the viscosity is measured at a shear rate of 0.1 s -1 . Regarding the temperature during measurement, it is set to a temperature matching the spinning conditions. The sample is placed on the plate. After the resin melts, the slit is set to 1 mm, and the part protruding from the Φ50 mm parallel plate is trimmed off. Then, wait until the sample reaches the measurement temperature, and then start the measurement. The viscosity value is obtained using the value after 100 seconds from the start of rotation as the measurement value.

[0156] The method for manufacturing the fibers of the present embodiment preferably performs the injection treatment of the heating fluid in the process of (II) above. This injection is performed on the state of the resin mixed molten liquid ejected from the nozzle before it is completely cured. By the heat of the injected heating fluid, the ejected resin mixed molten liquid can be stretched more actively, and finer fibers can be formed. The injection of the heating fluid can be carried out along the ejection direction of the resin mixed molten liquid, or in a direction intersecting the ejection direction.

[0157] From the viewpoint of making the above stretching more effective, the temperature of the above heating fluid is preferably higher than the curing point of the resin having the highest curing point among the thermoplastic resins contained in Component A.

[0158] Specifically, the difference between the temperature of the heating fluid and the curing point of the resin having the highest curing point among the thermoplastic resins contained in Component A is preferably 30°C or more, more preferably 40°C or more, and still more preferably 50°C or more.

[0159] In addition, from the viewpoint of suppressing resin decomposition, the difference between the temperature of the heating fluid and the curing point of the thermoplastic resin of Component A is preferably 200°C or less, more preferably 150°C or less, and still more preferably 130°C or less.

[0160] The method for manufacturing the fiber of the present embodiment preferably performs electrospinning treatment in the step (II) above. This electrospinning treatment can be carried out together with the above-described jet treatment of the heating fluid, or can be carried out in place of the jet treatment of the heating fluid.

[0161] The electrospinning treatment, also known as the electric field spinning method (electrospinning method), is a treatment in which a nozzle for ejecting resin is directly or indirectly charged, and an electric charge is imparted to the resin for spinning. Thereby, stretching can be carried out more actively, and finer fibers can be formed. For example, at a corresponding position spaced apart from the nozzle, a charging electrode and a high-voltage generating device connected to the charging electrode are arranged. With this configuration, a high voltage can be applied between the tip of the nozzle and the charging electrode to form an electric field therebetween, and the resin mixed melt ejected from the tip of the nozzle can be charged. The charging electrode is preferably made of a conductive material such as metal, or is covered with a dielectric material.

[0162] In the method for manufacturing the fiber of the present embodiment, in addition to Component A and Component B', other preparations may also be contained as long as the effects of the present invention are not impaired. For example, from the viewpoint of increasing the above-mentioned charge amount, a charge control agent, a lubricant, an antistatic agent, a hydrophilic agent, a surfactant, a plasticizer, etc. can be mentioned. In addition, an antioxidant, a neutralizing agent, a light stabilizer, an ultraviolet absorber, etc. can also be contained.

[0163] Through the step of collecting and forming into a sheet the fibers obtained by the method for manufacturing the fiber of the present embodiment in this way, the non-woven fabric of the present invention described above can be suitably manufactured. For example, the resin mixed melt ejected from the tip of the nozzle can be cooled and stretched while being collected in the collection part and stacked into a sheet to form a non-woven fabric. From the viewpoint of improving the collectability, the above-mentioned collection part preferably has a collection electrode and a high-voltage generating device connected to the collection electrode. The collection electrode and the high-voltage generating device of this collection part can also serve as the above-mentioned charging electrode and high-voltage generating device, or can be provided separately from them.

[0164] In the method for manufacturing the nonwoven fabric of the present embodiment, as described above, ultrafine fibers can be manufactured uniformly, efficiently, and at high speed from the resin melt mixture of Component A and Component B'. Therefore, the nonwoven fabric of the present invention with a larger area can be industrially and efficiently manufactured in an actual production line. That is, industrial production (mass production) of the nonwoven fabric of the present invention with a number-average fiber diameter of 4 μm or less and a wide sheet width can be achieved.

[0165] The method for manufacturing the nonwoven fabric of the present embodiment preferably employs a melting method using a melt. As other methods, a solution method using a polymer solution obtained by dissolving a polymer in a solvent for spinning can be cited. The melting method does not require processes such as solvent recovery, so it can be efficiently manufactured using a production line, and there is no need to worry about residual solvents in the manufactured products, enabling stable production. Therefore, it is preferred.

[0166] In the method for manufacturing the fibers of the present embodiment, as described for the nonwoven fabric of the present invention above, the fiber diameter of the above fibers is preferably 2 μm or less, more preferably 1.5 μm or less, and further preferably 1 μm or less.

[0167] The fiber diameter of the above fibers is preferably 0.1 μm or more, more preferably 0.2 μm or more.

[0168] In the method for manufacturing the nonwoven fabric of the present embodiment, as described for the nonwoven fabric of the present invention above, the number-average fiber diameter of the constituent fibers of the above nonwoven fabric is preferably 3 μm or less, more preferably 2 μm or less.

[0169] The above number-average fiber diameter is preferably 0.1 μm or more, more preferably 0.2 μm or more.

[0170] In addition, in the method for manufacturing the nonwoven fabric of the present embodiment, as described for the nonwoven fabric of the present invention above, the fiber median diameter of the constituent fibers of the above nonwoven fabric is preferably 2 μm or less, more preferably 1.5 μm or less, and further preferably 1 μm or less.

[0171] The above fiber median diameter is preferably 0.1 μm or more, more preferably 0.2 μm or more.

[0172] Examples

[0173] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these explanations. In addition, in the present examples, "parts" and "%" are based on mass unless otherwise specified. In Tables 1 to 3, "←" means the same content as in the left column, and "-" means that there is no value corresponding to the item.

[0174] (Examples 1 to 4)

[0175] The thermoplastic resin of Component A was set as PCL “Capa6250” (trade name, manufactured by Ingevity Corporation), and the compound of Component B was set as stearic acid “Lunac S-70V” (trade name, manufactured by Kao Corporation). A thermoplastic resin composition was prepared by mixing them in the proportions shown in Table 1. A molten liquid of the thermoplastic resin composition was prepared, and spinning was carried out using one nozzle with the pore diameter shown in Table 1 under the spinning conditions shown in Table 1. Simultaneously with the spinning, it was trapped in a sheet form to form nonwoven fabric specimens for Examples 1 to 4. In Example 1, the results of DSC (cooling) of Component A, Component B, and the thermoplastic resin composition obtained by mixing the two are as Figure 2 shown.

[0176] (Example 5)

[0177] The compound of Component B was set as behenic acid “NAA-222S” (trade name, manufactured by NOF Corporation). Except for this, a nonwoven fabric specimen was prepared in the same manner as in Example 2.

[0178] (Example 6)

[0179] The compound of Component B was set as behenic acid. Except for this, a nonwoven fabric specimen was prepared in the same manner as in Example 4.

[0180] (Example 7)

[0181] The compound of Component B was set as glyceryl behenate “Sunsoft No.8100-C” (trade name, manufactured by Sun Chemical Corporation). Except for this, a nonwoven fabric specimen was prepared in the same manner as in Example 2.

[0182] (Example 8)

[0183] The compound of Component B was set as distearyldimethylammonium chloride “Varisoft TA 100” (trade name, manufactured by Evonik Operations GmbH). Except for this, a nonwoven fabric specimen was prepared in the same manner as in Example 2.

[0184] (Example 9)

[0185] The compound of Component B was set as N-(hexadecyloxyhydroxypropyl)-N-hydroxyethyl hexadecanamide “SphingolipidE” (trade name, manufactured by Kao Corporation). Except for this, a nonwoven fabric specimen was prepared in the same manner as in Example 2.

[0186] (Example 10)

[0187] As an antistatic agent, sodium stearoyl lactate (SSL) (manufactured by Musashino Chemical Laboratory, Ltd.) was applied with a negative charge shown in Table 2. Except for this, a nonwoven fabric specimen was prepared in the same manner as in Example 7.

[0188] (Example 11)

[0189] The thermoplastic resin of Component A was set as two kinds of PCL with weight-average molecular weights as shown in Table 2. Except for this, a non-woven fabric specimen was produced in the same manner as in Example 10.

[0190] (Example 12)

[0191] The compound of Component B was set as glyceryl stearate “EXCEL S-95” (trade name, manufactured by Kao Corporation). Except for this, a non-woven fabric specimen was produced in the same manner as in Example 2.

[0192] (Example 13)

[0193] The compound of Component B was set as stearic monoamide “ALFLOW S-10” (trade name, manufactured by NOF Corporation). Using one nozzle with the pore diameter shown in Table 2, spinning was carried out under the spinning conditions shown in Table 2. Except for this, a non-woven fabric specimen of Example 13 was produced in the same manner as in Example 2.

[0194] (Example 14)

[0195] The compound of Component B was set as myristyl alcohol “KALCOL 4098” (trade name, manufactured by Kao Corporation). The temperature of the heating fluid was set to 130 °C. Except for this, the same operations as in Example 13 were carried out to produce a non-woven fabric specimen of Example 14.

[0196] (Example 15)

[0197] The compound of Component B was set as zinc stearate “ZINC STEARATE G” (trade name, manufactured by NOF Corporation). The heating temperature and the heating fluid temperature during the formation of the molten liquid were set to 150 °C. Except for this, a non-woven fabric specimen was produced in the same manner as in Example 13.

[0198] (Example 16)

[0199] The compound of Component B was set as glyceryl behenate. The addition amount was set to 5% by mass. The heating temperature during the formation of the molten liquid was set to 120 °C. Except for this, a non-woven fabric specimen was produced in the same manner as in Example 15.

[0200] (Example 17)

[0201] The addition amount of Component B was set to 11% by mass. Except for this, a non-woven fabric specimen was produced in the same manner as in Example 16.

[0202] (Example 18)

[0203] The addition amount of Component B was set to 40% by mass. Except for this, a non-woven fabric specimen was produced in the same manner as in Example 16.

[0204] (Comparative Example 1)

[0205] Spinning was carried out in the same manner as in Example 1 except that the compound of Component B was not used. However, fibrillation was not possible and a nonwoven fabric could not be produced.

[0206] (Comparative Example 2)

[0207] The additive of Component B was set to lauryl alcohol “KALCOL 2098” (trade name, manufactured by Kao Corporation), and the spinning conditions were as shown in Table 3. Otherwise, a nonwoven fabric specimen was produced in the same manner as in Example 2.

[0208] (Comparative Example 3)

[0209] The additive of Component B was set to sodium N-stearoyl-N-methyltaurate “NIKKOL-SMT” (trade name, manufactured by Nikko Chemicals Co., Ltd.), the heating temperature during the formation of the molten liquid was set to 180 °C, and the spinning conditions were as shown in Table 3. Otherwise, an attempt was made to spin in the same manner as in Example 2, but a nonwoven fabric could not be produced due to nozzle clogging.

[0210] (Comparative Example 4)

[0211] The additive of Component B was set to glyceryl behenate, the addition amount was set to 1% by mass, and the spinning conditions were as shown in Table 3. Otherwise, a nonwoven fabric specimen was produced in the same manner as in Example 2.

[0212] (Comparative Example 5)

[0213] An attempt was made to spin with the additive of Component B being glyceryl behenate and the addition amount being 60% by mass, but mixing was not possible and spinning could not be carried out.

[0214] [Table 1]

[0215] Table 1

[0216]

[0217] [Table 2] Table 2

[0218]

[0219] [Table 3]

[0220] Table 3

[0221]

[0222] In Comparative Example 1, curing did not occur during spinning. As Figure 4 shown, the molten thermoplastic resin composition agglomerated and fibers could not be formed. In contrast, in Example 1, as Figure 3As shown in (A) to (C) thereof, ultrafine fibers with a median fiber diameter of around 1 μm were uniformly formed. As a result, as shown in Table 1, a nonwoven fabric sample with a sheet width of 300 mm could be manufactured with a number-average fiber diameter of 1.9 μm and a fiber median diameter of 0.7 μm.

[0223] In addition, in Examples 2 to 18, the fibers were well formed and made into nonwoven fabrics, and nonwoven fabric samples with the number-average fiber diameter, fiber median diameter, and sheet width shown in Tables 1 and 2 could be manufactured.

[0224] The present invention has been described in connection with its embodiments and examples, but unless otherwise specified, the present invention is not limited to any details of the description, and can be broadly interpreted as long as it does not deviate from the spirit and scope of the invention shown in the scope of the appended claims.

[0225] This application claims priority based on Japanese Patent Application No. 2022-189675 filed in Japan on November 28, 2022, and their contents are incorporated herein by reference as part of the description of this specification.

[0226] Symbol Explanation

[0227] 1. Constituent fiber; 2. Core layer of Component A; 3. Skin layer of Component B.

Claims

1. A method for manufacturing a fiber, characterized in that: it includes a step (I) of heating and melting a thermoplastic resin composition and a step (II) of ejecting from a nozzle, and spinning is carried out with a fiber diameter of 4 μm or less. The thermoplastic resin composition contains, based on the total mass of the thermoplastic resin composition, 50% by mass or more and 95% by mass or less of the following component A and 5% by mass or more and 50% by mass or less of the following component B'. Component A: A thermoplastic resin having a curing point of 100°C or lower. Component B': A compound having a curing point higher than the curing point of the resin having the highest curing point among the thermoplastic resins and a melting point lower than the processing temperature.

2. The method for manufacturing a fiber according to claim 1, characterized in that: in the step (II), jet treatment of a heating fluid is carried out.

3. The method for manufacturing a fiber according to claim 1 or 2, characterized in that: the temperature of the heating fluid is higher than the curing point of the resin having the highest curing point among the thermoplastic resins contained in component A, and the difference is preferably 30°C or more and 200°C or less, more preferably 40°C or more and 150°C or less, and further preferably 50°C or more and 130°C or less.

4. The method for manufacturing a fiber according to any one of claims 1 to 3, characterized in that: in the step (II), electrostatic spinning treatment is carried out.

5. The method for manufacturing a fiber according to any one of claims 1 to 4, characterized in that: in the step (II), the ejection speed of the molten liquid of the thermoplastic resin composition from the nozzle is set to 0.1 g / minute·nozzle or more, preferably 0.1 g / minute·nozzle or more and 20 g / minute·nozzle or less, more preferably 0.2 g / minute·nozzle or more and 10 g / minute·nozzle or less, and further preferably 0.5 g / minute·nozzle or more and 10 g / minute·nozzle or less.

6. The method for manufacturing a fiber according to any one of claims 1 to 5, characterized in that: component B' contains one or more selected from fatty acids, higher alcohols, fatty acid amide compounds, polyol organic acid ester compounds, waxes, sphingolipids, alkyl ammonium salts, and fatty acid metal salts.

7. The method for manufacturing a fiber according to any one of claims 1 to 6, characterized in that: component A contains a thermoplastic resin having a curing point of 0°C or higher and 75°C or lower, preferably 0°C or higher and 60°C or lower.

8. The method for manufacturing a fiber according to any one of claims 1 to 7, characterized in that: the processing temperature is higher than the melting point of the resin having the highest melting point among the thermoplastic resins, and the difference is 20°C or more and 200°C or less.

9. The method for manufacturing a fiber according to any one of claims 1 to 8, characterized in that: based on the total mass of the thermoplastic resin composition, it contains 60% by mass or more and 95% by mass or less, preferably 65% by mass or more and less than 90% by mass, and more preferably 70% by mass or more and 85% by mass or less of component A.

10. The method for manufacturing a fiber according to any one of claims 1 to 9, characterized in that: Component B' is contained in an amount of 10% by mass or more and 40% by mass or less, preferably more than 10% by mass and 35% by mass or less, more preferably more than 10% by mass and 30% by mass or less, based on the total mass of the thermoplastic resin composition.

11. The method for producing a fiber according to any one of claims 1 to 10, characterized in that: The fiber diameter of the fiber is 0.1 μm or more and 2 μm or less, preferably 0.2 μm or more and 1.5 μm or less, more preferably 0.2 μm or more and 1 μm or less.

12. A method for producing a nonwoven fabric, characterized in that: It includes a step of collecting the fibers obtained by the method for producing a fiber according to any one of claims 1 to 11 and forming them into a sheet.

13. The method for producing a nonwoven fabric according to claim 12, characterized in that: The median fiber diameter of the constituent fibers of the nonwoven fabric is 0.1 μm or more and 2 μm or less, preferably 0.2 μm or more and 1.5 μm or less, more preferably 0.2 μm or more and 1 μm or less.

14. A nonwoven fabric containing fibers, characterized in that: The interior of the fiber contains the following component A and component B, Component A is contained in an amount of 50% by mass or more and 95% by mass or less, and component B is contained in an amount of 5% by mass or more and 50% by mass or less, based on the total mass of the nonwoven fabric. The number-average fiber diameter of the fibers contained in the nonwoven fabric is 4 μm or less. The sheet width of the nonwoven fabric is 50 mm or more. Component A: A thermoplastic resin having a curing point of 100 °C or lower. Component B: A compound having a curing point higher than that of the resin having the highest curing point among the thermoplastic resins and a melting point lower than 150 °C.

15. The nonwoven fabric according to claim 14, characterized in that: Component B contains a compound having a weight-average molecular weight of 1000 g / mol or less, preferably contains a compound having a weight-average molecular weight of 100 g / mol or more and 1000 g / mol or less.

16. The nonwoven fabric according to claim 14 or 15, characterized in that: Component B contains one or more selected from fatty acids, higher alcohols, fatty acid amide compounds, polyol organic acid ester compounds, waxes, sphingolipids, alkyl ammonium salts, and fatty acid metal salts. Preferably, component B contains one or more selected from fatty acids, higher alcohols, fatty acid amide compounds, polyglycerol fatty acid ester compounds, sucrose fatty acid ester compounds, and sorbitan fatty acid ester compounds.

17. The nonwoven fabric according to any one of claims 14 to 16, characterized in that: Among the compounds contained in component B, the proportion of the compound having a salt structure is more than 0% by mass and 5% by mass or less, preferably 0.5% by mass or more and 3% by mass or less, more preferably 0.5% by mass or more and 1% by mass or less.

18. The nonwoven fabric according to any one of claims 14 to 17, characterized in that: The median fiber diameter of the constituent fibers of the nonwoven fabric is 2 μm or less.

19. The nonwoven fabric according to any one of claims 14 to 18, characterized in that: Component A contains a thermoplastic resin with a solidification point of 0°C or higher and 75°C or lower, preferably 0°C or higher and 60°C or lower.

20. The non-woven fabric according to any one of claims 14 to 19, characterized in that: Component A contains a thermoplastic resin with a melting point of 50°C or higher and 150°C or lower, preferably 50°C or higher and 120°C or lower, more preferably 50°C or higher and 90°C or lower.

21. The non-woven fabric according to any one of claims 14 to 20, characterized in that: Relative to the mass of the entire non-woven fabric, it contains 60% by mass or more and 95% by mass or less of Component A, preferably 65% by mass or more and less than 90% by mass, more preferably 70% by mass or more and 85% by mass or less.

22. The non-woven fabric according to any one of claims 14 to 21, characterized in that: When it is the combination with the largest difference between the melting point of the thermoplastic resin contained in Component A and the melting point of the compound contained in Component B, the difference is preferably more than 0°C and 100°C or lower, more preferably more than 0°C and 60°C or lower, further preferably more than 0°C and 50°C or lower.

23. The non-woven fabric according to any one of claims 14 to 22, characterized in that: Component B contains a compound with a melting point of 30°C or higher and lower than 150°C, preferably 40°C or higher and 135°C or lower, more preferably 50°C or higher and 120°C or lower.

24. The non-woven fabric according to any one of claims 14 to 23, characterized in that: Relative to the mass of the entire non-woven fabric, it contains 10% by mass or more and 40% by mass or less of Component B, preferably more than 10% by mass and 35% by mass or less, more preferably more than 10% by mass and 30% by mass or less.

25. The non-woven fabric according to any one of claims 14 to 24, characterized in that: The number-average fiber diameter of the constituent fibers of the non-woven fabric is 0.1 μm or more and 3 μm or less, preferably 0.2 μm or more and 2 μm or less.

26. The non-woven fabric according to any one of claims 14 to 25, characterized in that: The fiber median diameter of the constituent fibers of the non-woven fabric is 0.1 μm or more and 2 μm or less, preferably 0.2 μm or more and 1.5 μm or less, more preferably 0.2 μm or more and 1 μm or less.

27. The non-woven fabric according to any one of claims 14 to 26, characterized in that: The sheet width of the non-woven fabric is 50 mm or more and 3000 mm or less, preferably 100 mm or more and 3000 mm or less, more preferably 150 mm or more and 3000 mm or less, further preferably 200 mm or more and 3000 mm or less, still more preferably 300 mm or more and 3000 mm or less.

28. The non-woven fabric according to any one of claims 14 to 27, characterized in that: The "sheet width" / "length orthogonal to the sheet width" of the non-woven fabric is 1 or more and 8 or less, preferably 1 or more and 4 or less, more preferably 1 or more and 2 or less, further preferably 1 or more and 1.5 or less.

29. The non-woven fabric according to any one of claims 14 to 28, characterized in that: The component A includes one or more selected from polyester resins and polyether resins.

30. The non-woven fabric according to any one of claims 14 to 29, characterized in that: The component A includes one or more selected from polycaprolactone, polybutylene succinate, polybutylene adipate succinate, polydioxanone and polyglycolic acid.

31. The non-woven fabric according to claim 30, characterized in that: The component A includes polycaprolactone.

32. The non-woven fabric according to any one of claims 14 to 31, characterized in that: The weight-average molecular weight of the thermoplastic resin contained in the component A is 5,000 g / mol or more and 200,000 g / mol or less, preferably 10,000 g / mol or more and 150,000 g / mol or less, more preferably 10,000 g / mol or more and 100,000 g / mol or less.

33. The non-woven fabric according to any one of claims 14 to 32, characterized in that: The component B includes one or more selected from stearic acid, behenic acid, myristyl alcohol and glyceryl behenate, preferably one or more selected from stearic acid, behenic acid and glyceryl behenate.

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