Nonwoven fabric and manufacturing method thereof, laminate, clothing, and miscellaneous goods

Abstract

To provide a nonwoven fabric having excellent tear strength in addition to sufficient water pressure resistance.SOLUTION: A nonwoven fabric consists of fibers made of thermoplastic resin. Number average fiber diameter of the fibers is 10 nm or more and 500 nm or less. Percentage of fibers having fiber diameter of 100 nm or more and 5000 nm or less in the nonwoven fabric is 5% or more and 50% or less. Percentage of fibers having fiber diameter of 10 nm or more and 5000 nm or less is 99% or more. Zero shear viscosity at 230°C is 50.0 Pa s or more and 500.0 Pa s or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a nonwoven fabric and a method for producing the same. [Background technology]

[0002] The melt-blowing method, one of the methods for producing nonwoven fabrics, is widely recognized as a method capable of mass-producing nonwoven fabrics made of fibers with an average fiber diameter of approximately 2 to 5 μm. In recent years, various studies have been conducted to determine whether nonwoven fabrics containing fibers with a fiber diameter of less than 1 μm can be obtained. For example, Patent Document 1 proposes a nonwoven fabric made of a thermoplastic polymer, having an average fiber diameter of 50 nm to 800 nm and a fiber diameter variation rate within a specific range. It is described that this nonwoven fabric can provide low pressure loss and high collection performance. Furthermore, Patent Document 2 proposes a nonwoven fabric having an average fiber diameter of 5 μm or less and a fiber diameter cumulative frequency of 100 nm to 200 nm within a specific range. It is described that this nonwoven fabric provides a large surface area and fine voids, making it suitable for use in filters. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-23391 [Patent Document 2] International Publication No. 2017 / 142021 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology disclosed in Patent Document 1, the tear strength is relatively low, so there is still room for improvement in processability. On the other hand, in the technology disclosed in Patent Document 2, a certain number of fibers with large diameters are contained, so there is a problem that the water pressure resistance is very low.

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a nonwoven fabric that has sufficient water pressure resistance and also excellent tear strength. [Means for solving the problem]

[0006] As a result of extensive research, the inventors of the present invention have found that by adjusting the number-average fiber diameter of the fibers constituting a nonwoven fabric and the zero shear viscosity of the nonwoven fabric to specific ranges, the tear strength can be improved to some extent, but not sufficiently. Therefore, as a result of further extensive research, they have found that by adjusting the ratio of fibers having a certain fiber diameter to a specific range, a nonwoven fabric can be obtained that has high water pressure resistance and excellent tear strength. Furthermore, they have found that this nonwoven fabric also has excellent moisture permeability and breathability.

[0007] The present invention has been completed based on these findings, and provides the following inventions.

[0008] [1] A nonwoven fabric made of fibers made of a thermoplastic resin, The number average fiber diameter of the fibers is 10 nm or more and 500 nm or less, The nonwoven fabric is The ratio of fibers having a fiber diameter of 100 nm or more and 5000 nm or less is 5% or more and 50% or less, The proportion of fibers having a fiber diameter of 10 nm or more and 5000 nm or less is 99% or more, moreover, The zero shear viscosity at 230°C is 50.0 Pa·s or more and 500.0 Pa·s or less. Nonwoven fabric.

[0009] [2] The nonwoven fabric according to [1], which has at least one endothermic peak in the range of 30.0°C to 125.0°C in differential scanning calorimetry.

[0010] [3] The nonwoven fabric according to [1] or [2], wherein the proportion of fibers having a fiber diameter of 10 nm or more and 100 nm or less is 50% or more and 95% or less.

[0011] [4] The nonwoven fabric according to any one of [1] to [3] above, wherein the fiber diameter distribution of the fibers is 1.50 or more and 3.50 or less.

[0012] [5] A laminate comprising the nonwoven fabric according to any one of [1] to [4].

[0013] [6] Clothing comprising the laminate described in [5] above.

[0014] [7] Miscellaneous goods including the laminate described in [5].

[0015] [8] Thermoplastic resin P soluble in alkaline aqueous solution A1 and, Thermoplastic resin P insoluble in alkaline aqueous solution B1 and, a step of melt-spinning the raw material resin from the discharge holes of the spinneret and collecting the spun yarn in a collecting device below to form a fiber sheet; The thermoplastic resin P of the fiber sheet A1 a step of treating the compound with an alkaline aqueous solution to elute the compound; A method for producing a nonwoven fabric comprising forming a nonwoven fabric composed of fibers made of a thermoplastic resin, The number average fiber diameter of the fibers is 10 nm or more and 500 nm or less, The nonwoven fabric is The ratio of fibers having a fiber diameter of 100 nm or more and 5000 nm or less is 5% or more and 50% or less, The proportion of fibers having a fiber diameter of 10 nm or more and 5000 nm or less is 99% or more, moreover, The zero shear viscosity at 230°C is 50.0 Pa·s or more and 500.0 Pa·s or less. Method for manufacturing nonwoven fabric.

[0016] [9] The raw material resin is the thermoplastic resin P A1 and the thermoplastic resin P B1 and further, the thermoplastic resin P B2 The method for producing a nonwoven fabric according to [8] above,

[0017]

[10] The method for producing a nonwoven fabric according to [8] or [9], wherein the raw material resins are all thermoplastic resins kneaded in a twin or more screw extruder. [Effects of the Invention]

[0018] According to the present invention, a nonwoven fabric can be obtained that has high water pressure resistance, moisture permeability, breathability, and excellent tear strength. Because this nonwoven fabric has the above-mentioned properties, it is suitable for use as a laminate, and further as clothing containing this laminate. DETAILED DESCRIPTION OF THE INVENTION

[0019] The nonwoven fabric of the present invention is a nonwoven fabric composed of fibers made of a thermoplastic resin, the fibers having a number average fiber diameter of 10 nm or more and 500 nm or less, the proportion of fibers having a fiber diameter of 100 nm or more and 5000 nm or less in the nonwoven fabric is 5% or more and 50% or less, and the proportion of fibers having a fiber diameter of 10 nm or more and 5000 nm or less in the nonwoven fabric is 99% or more, and further, the zero shear viscosity at 230°C is 50.0 Pa s or more and 500.0 Pa s or less.

[0020] The components will be described in detail below, but the present invention is not limited to the scope of the following description as long as it does not deviate from the gist of the present invention.

[0021] [Thermoplastic resin] The fibers constituting the nonwoven fabric of the present invention are made of a thermoplastic resin. Examples of such thermoplastic resins include polyolefins, polyesters, polyamides, acid-modified polyolefins (e.g., various types of maleic anhydride-modified polypropylene "UMEX (registered trademark)" manufactured by Sanyo Chemical Industries, Ltd.), and "MARICON (registered trademark)" manufactured by Osaka Gas Chemicals Co., Ltd. Mixtures of these may also be used. Examples of polyolefins include polypropylene and polyethylene (including high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE)), as well as mixtures and copolymers thereof. Examples of polyesters include polyethylene terephthalate, polybutylene terephthalate, and mixtures and copolymers thereof. Examples of polyamides include polyamide 6, polyamide 6,6, and mixtures and copolymers thereof. Among these, polyolefins are preferred because they tend to have a small contact angle with water, thereby improving the water pressure resistance of the nonwoven fabric. Among polyolefins, polypropylene and high density polyethylene are more preferred because they have a particularly large contact angle with water and can further improve the water pressure resistance of the nonwoven fabric.

[0022] Such thermoplastic resins may contain various additives such as inorganic substances such as titanium oxide, silica, barium oxide, and calcium carbonate, colorants such as carbon black, dyes, and pigments, flame retardants, fluorescent brighteners, antioxidants, charge stabilizers, antistatic agents, and ultraviolet absorbers.

[0023] The melting point of the thermoplastic resin is preferably greater than 125° C. and not greater than 230° C., and more preferably greater than 125° C. and not greater than 200° C. Thermoplastic resins having melting points within the above range are suitable for thermal bonding at relatively low temperatures, and are preferred because they are less likely to impair the mechanical properties of other nonwoven fabrics, woven fabrics, knitted fabrics, etc. when they are laminated on the nonwoven fabric of the present invention.

[0024] In the present invention, the melting point of the thermoplastic resin is a value measured and calculated by the following method. (1) Randomly collect test pieces of approximately 2 mg from the nonwoven fabric, excluding the edges. (2) The test piece is placed in a differential scanning calorimeter (for example, the DSC6200 manufactured by Seiko Instruments Inc.), and the temperature is increased to 300°C at a rate of 10°C / min in a nitrogen atmosphere until melted, and then the temperature is decreased to 20°C by air cooling. (3) The sample that has become solid again is subjected to differential scanning calorimetry in a nitrogen atmosphere at a temperature increase rate of 10°C / min and a measurement temperature range of 20 to 300°C. (4) The temperature at the apex of the endothermic peak in the obtained measurement results (DSC curve) is taken as the melting point (°C). If multiple endothermic peaks are observed, the temperature at the apex of the peak with the greatest endothermic amount is taken as the melting point (°C). (5) Repeat steps (1) to (4) twice, and round off the arithmetic mean (°C) of the melting points (°C) obtained in each measurement to the nearest tenth.

[0025] [fiber] The fibers constituting the nonwoven fabric of the present invention are made of the thermoplastic resin. The number-average fiber diameter of these fibers is 10 nm or more and 500 nm or less. When the lower limit of this number-average fiber diameter range is 10 nm or more, preferably 20 nm or more, and more preferably 40 nm or more, the nonwoven fabric has excellent breathability and moisture permeability. On the other hand, when the upper limit of the number-average fiber diameter range is 500 nm or less, preferably 450 nm or less, and more preferably 400 nm or less, the maximum pore size of the nonwoven fabric is small, resulting in a nonwoven fabric with high water pressure resistance.

[0026] In the present invention, the number average fiber diameter (nm) of the fibers is a value measured and calculated by the following method. (1) Cut out 10mm x 5mm measurement samples from three points across the width of the nonwoven fabric (two at the side edges and one at the center), plus five points spaced 5cm apart in the longitudinal direction, for a total of 15 points. At this time, check that the samples do not contain any obvious defects in appearance, such as shot (polymer clumps resulting from thread breakage). If any are found, remove the measurement sample in question and cut out the remaining measurement samples of the above dimensions at random from positions that do not contain the defects. (2) Using a scanning electron microscope (SEM, for example, the S-5500 manufactured by Hitachi High-Technologies Corporation), photographs of the surface of the nonwoven fabric are taken from the cut-out measurement samples at a magnification of 30,000x, for a total of 15 photographs. (3) Measure the width (nm) of all fibers in the photograph where the width of the fiber side surface can be clearly seen. Even if the cross-sectional shape of the fiber is flat or irregular, as described above, measure the width of the fiber side surface as the fiber diameter. (4) Repeat steps (2) and (3) for all measurement samples. (5) The arithmetic mean value (nm) of all the obtained fiber diameters is rounded to the nearest integer.

[0027] [Nonwoven fabric] The nonwoven fabric of the present invention is composed of the above-mentioned fibers. The proportion of fibers having a fiber diameter of 100 nm or more and 5000 nm or less is 5% or more and 50% or less, and the proportion of fibers having a fiber diameter of 10 nm or more and 5000 nm or less is 99% or more. Only by satisfying both of these requirements can a nonwoven fabric have high water pressure resistance and excellent moisture permeability and breathability.

[0028] First, the nonwoven fabric of the present invention has a ratio of fibers having a fiber diameter of 100 nm or more and 5000 nm or less of 5% or more and 50% or less. The ratio here refers to the ratio by number (proportion of fibers). By ensuring that the ratio of fibers in this fiber diameter range is 5% or more, preferably 7% or more, and more preferably 10% or more, the breathability and tear strength of the nonwoven fabric are improved. On the other hand, by ensuring that the ratio of fibers in this fiber diameter range is 50% or less, preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less, the water pressure resistance of the nonwoven fabric is improved.

[0029] Next, the nonwoven fabric of the present invention has a fiber ratio of 99% or more having a fiber diameter of 10 nm or more and 5000 nm or less. The ratio here also refers to a ratio by number (proportion by number). A nonwoven fabric having a fiber ratio of less than 99% having a fiber diameter of 10 nm or more and 5000 nm or less is not preferred because it cannot achieve both high water pressure resistance and excellent breathability.

[0030] In the present invention, the percentage of fibers having a fiber diameter of 100 nm or more and 5000 nm or less, and the percentage of fibers having a fiber diameter of 10 nm or more and 5000 nm or less refer to values ​​obtained by measuring the number average fiber diameter of fibers, calculating the percentage of the number of fibers using the following formulas 1 and 2 based on all fiber diameter values ​​obtained by carrying out the calculation methods (1) to (4), and rounding the obtained value (%) to one decimal place. [Percentage of fibers with a fiber diameter of 100 nm or more and 5000 nm or less (%)] = [Number of fibers with a fiber diameter of 100 nm or more and 5000 nm or less (number of fibers)] ÷ [Total number of measured fibers (number of fibers)] × 100 (Equation 1) [Percentage of fibers with a fiber diameter of 10 nm or more and 5000 nm or less (%)] = [Number of fibers with a fiber diameter of 10 nm or more and 5000 nm or less (number of fibers)] ÷ [Total number of measured fibers (number of fibers)] × 100 (Equation 2) The proportion of fibers with a fiber diameter of 100 nm or more and 5000 nm or less can be adjusted by the combination of thermoplastic resins constituting the raw material resin (described later) and the hot air pressure in the spinning process, and the proportion of fibers with a fiber diameter of 10 nm or more and 5000 nm or less can be adjusted by the zero shear viscosity of the raw material resin and the spinning temperature.

[0031] The nonwoven fabric of the present invention preferably has a fiber diameter of 10 nm or more and 100 nm or less in a proportion of 50% or more and 95% or less. By making the proportion of fibers in this fiber diameter range preferably 50% or more, more preferably 60% or more, and even more preferably 65% ​​or more, it is possible to improve water pressure resistance. On the other hand, by making the proportion of fibers in this fiber diameter range preferably 95% or less, more preferably 93% or less, and even more preferably 90% or less, it is possible to obtain a nonwoven fabric with excellent breathability.

[0032] In the present invention, the percentage of fibers having a fiber diameter of 10 nm or more and 100 nm or less refers to the value obtained by calculating the percentage of the number of fibers using the following formula 3 based on all the fiber diameter values ​​obtained by measuring the number average fiber diameter of fibers and performing calculation methods (1) to (4), and rounding the obtained value (%) to one decimal place. [Percentage of fibers with a fiber diameter of 10 nm or more and 100 nm or less (%)] = [Number of fibers with a fiber diameter of 10 nm or more and 100 nm or less (number of fibers)] ÷ [Total number of measured fibers (number of fibers)] × 100 (Equation 3) The ratio of fibers having a fiber diameter of 10 nm or more and 100 nm or less can be adjusted by the hot air pressure in the spinning process, the discharge amount of the raw material resin, and the like.

[0033] Furthermore, the nonwoven fabric of the present invention preferably has a fiber diameter distribution of 1.50 or more and 3.50 or less. A fiber diameter distribution of preferably 1.50 or more, more preferably 1.55 or more, and even more preferably 1.60 or more results in a nonwoven fabric with excellent breathability. On the other hand, a fiber diameter distribution of preferably 3.50 or less, more preferably 3.00 or less, and even more preferably 2.75 or less results in a nonwoven fabric with higher water pressure resistance.

[0034] In the present invention, the fiber diameter distribution of fibers refers to values ​​measured and calculated by the following method. (1) Measure the number average fiber diameter of the fibers, and calculate the weight average fiber diameter (nm) from all the fiber diameter values ​​obtained by performing the calculation methods (1) to (4) using the following formula 4. [Weight average fiber diameter (nm)]=Σ[{Fiber diameter (nm)} 2 ] ÷ Σ [fiber diameter (nm)] (Equation 4) (2) Divide the weight average fiber diameter (nm) obtained in (1) by the number average fiber diameter (nm) (before rounding), and round the resulting value to two decimal places.

[0035] The fiber diameter distribution of the fibers can be adjusted by the combination of thermoplastic resins constituting the raw material resin, which will be described later, or the hole diameter of the spinneret used in the spinning process.

[0036] Additionally, the nonwoven fabric of the present invention has a zero shear viscosity at 230°C of 50 Pa·s or more and 500 Pa·s or less. By setting the lower limit of this zero shear viscosity range to 50 Pa·s or more, preferably 60 Pa·s or more, the nonwoven fabric will have high tear strength and excellent durability. On the other hand, by setting the upper limit of the zero shear viscosity range to 500 Pa·s or less, preferably 450 Pa·s or less, the nonwoven fabric will have excellent tear strength.

[0037] In the present invention, the zero shear viscosity of a nonwoven fabric refers to a value measured and calculated as follows. (1) Two test pieces are taken from any position on the nonwoven fabric. The amount taken is sufficient to fill the space between the parallel plates of the rheometer described below, i.e., sufficient to fill a cylinder with a base radius of 10 mm and a height of 0.5 mm. This amount should be at least 0.15 g and adjusted according to the specifications of the measuring device. (2) Using a rheometer (for example, "Reosol G3000" manufactured by UBM Corporation), set the parallel plates on which the above test pieces are set, and measure the melt viscosity when strain is applied at angular frequencies of 1.26 rad / sec, 3.14 rad / sec, 6.28 rad / sec, 12.57 rad / sec, 31.42 rad / sec, and 62.83 rad / sec. (3) The relationship between angular frequency and melt viscosity is linearly approximated for the results obtained from the two test pieces. (4) The melt viscosity value calculated by extrapolating the linear approximation to 0 rad / sec is defined as the zero shear viscosity.

[0038] The zero shear viscosity of the nonwoven fabric of the present invention at 230°C can be controlled by the melt flow rate and molecular weight distribution of the thermoplastic resin, the temperature and residence time of the extruder or spinning machine in the spinning process, etc.

[0039] The nonwoven fabric of the present invention preferably has at least one endothermic peak in the range of 30.0° C. to 125.0° C. in differential scanning calorimetry (DSC). Having an endothermic peak in this range allows the nonwoven fabric to have higher tear strength.

[0040] The presence or absence of an endothermic peak can be confirmed by the following method. (1) A test piece of approximately 2 mg is randomly taken from the nonwoven fabric, excluding the edges, and set in the differential scanning calorimeter. (2) Differential scanning calorimetry is performed on the set sample in a nitrogen atmosphere at a temperature rise rate of 10°C / min within a measurement temperature range of 20 to 300°C, and the obtained measurement results (DSC curve) are checked for the presence or absence of at least one endothermic peak within the range of 30°C to 125°C. (3) Repeat steps (1) and (2) twice, and if an endothermic peak is found both times, it is determined that the endothermic peak is in the above range. If one of the two times shows an endothermic peak and the other does not, repeat the procedure once more, and if the result shows an endothermic peak, it is determined that the endothermic peak is in the above range.

[0041] The nonwoven fabric of the present invention preferably has a porosity of 25.0% or more and 99.0% or less. A porosity of preferably 25.0% or more, more preferably 40.0% or more, results in a nonwoven fabric with higher moisture permeability. Furthermore, a porosity of preferably 99.0% or less, more preferably 90.0% or less, results in a nonwoven fabric with better mechanical properties such as tensile strength and tear strength.

[0042] In the present invention, the void ratio (%) of a nonwoven fabric refers to a value measured and calculated as follows. (1) The thickness (μm) of the nonwoven fabric is determined as described in the following (1-1) to (1-2). (1-1) Ten test pieces measuring 7.0 cm x 7.0 cm are cut out from the area of ​​the nonwoven fabric excluding 30 mm from the edge. (1-2) Using a thickness measuring device (for example, "HKT-Lite1.0F" manufactured by Fuji Work Co., Ltd.), measure the thickness (μm) when a pressure of 0.5 kPa is applied. (1-3) Perform the measurement in (1-2) for all samples, and round off the arithmetic mean value of the measurement results to the first decimal place. (2) Weight of nonwoven fabric (g / m 2 ) is calculated as described in (2-1) to (2-2) below. (2-1) Three test pieces measuring 250 mm x 250 mm are cut out from the nonwoven fabric, excluding a 30 mm area at the edge. (2-2) Weigh each test piece and measure the unit area (1 m 2 ) converted to mass (g) per unit mass (g / m 2 ) and round off to the first decimal place to obtain an integer value. (3) The basis weight (g / m 2 ) and thickness (μm), density of the thermoplastic resin that makes up the nonwoven fabric (g / cm 3 ) to round the value obtained from the following formula 5 to two decimal places. Porosity (%) = [1 - (weight (g / m 2 ) / Thickness (μm) / Density (g / cm 3 ))〕×100 ···(Equation 5).

[0043] The porosity (%) of the nonwoven fabric of the present invention can be adjusted by the hot air pressure in the melt-spinning step described below, the amount of raw resin discharged, and the like.

[0044] The nonwoven fabric of the present invention has an air permeability of 0.1 cm 3 / (cm 2 · seconds) or more 10.0cm 3 / (cm 2 The air permeability is preferably 0.1 cm sec. 3 / (cm 2 sec) or more, preferably 0.3 cm 3 / (cm 2 seconds), more preferably 0.5 cm 3 / (cm 2sec.), when used in the waterproof layer of clothing, the nonwoven fabric can easily release water vapor generated by sweating, etc., to the outside of the body, thereby further suppressing the drop in body temperature. 3 / (cm 2 · seconds) or less, preferably 7.0 cm 3 / (cm 2 sec) or less, more preferably 5.0 cm 3 / (cm 2 By achieving a water-resistant resistance of less than 100 sq. m (1.5 s), the nonwoven fabric can better prevent the penetration of virus droplets and other particles when used as a water-resistant layer in protective clothing.

[0045] In the present invention, the breathability (cm 3 / (cm 2 · seconds)) refers to the value measured and calculated as follows: (1) Five measurement samples measuring 100 mm x 100 mm are cut out from the area of ​​the nonwoven fabric excluding the edge 30 mm. (2) Place one measurement sample in a breathability evaluation device (e.g., the FX3340 manufactured by Textest Co., Ltd.), and measure based on "Method A (Fragile method)" described in "8.26 Breathability" of JIS L1096:2010 "Testing methods for woven and knitted fabrics." (3) Perform the measurement (2) on all measurement samples and calculate the arithmetic mean value of the five measurements.

[0046] The breathability of the nonwoven fabric of the present invention can be adjusted by the spinning temperature and hot air temperature in the melt spinning step described below.

[0047] [Nonwoven fabric manufacturing method] Next, a preferred embodiment for producing the nonwoven fabric of the present invention will be specifically explained, but the present invention is not limited to this embodiment.

[0048] The method for producing the nonwoven fabric of the present invention comprises the steps of: A1 and thermoplastic resin P, which is insoluble in alkaline aqueous solution. B1A step of melt-spinning a raw material resin consisting of the above from a discharge hole of a spinneret, and collecting the spun yarn in a collecting device below to form a fiber sheet; A1 and a step of treating the resulting nonwoven fabric with an alkaline aqueous solution to dissolve the thermoplastic resin fibers. Each step will be described below.

[0049] (a) forming a fiber sheet In this process, a thermoplastic resin P soluble in an alkaline aqueous solution is used. A1 and thermoplastic resin P, which is insoluble in alkaline aqueous solution. B1 The raw resin material is melt-spun through the discharge holes of the spinneret, and the spun yarn is collected in a collecting device below to form a fiber sheet.

[0050] (a-1) Raw resin The raw material resin used in this process is a thermoplastic resin P that is soluble in an alkaline aqueous solution. A1 and thermoplastic resin P, which is insoluble in alkaline aqueous solution. B1 It consists of:

[0051] In the present invention, a thermoplastic resin soluble in an alkaline aqueous solution refers to a thermoplastic resin having a dissolution rate of 1.0 g / hour or more in an alkaline aqueous solution (aqueous sodium hydroxide solution with a concentration of 1% by mass) shown below, and a thermoplastic resin that does not satisfy the above condition is considered to be a thermoplastic resin insoluble in an alkaline aqueous solution.

[0052] The elution rate (g / min) of a thermoplastic resin into an alkaline aqueous solution refers to a value measured and calculated as follows. (1) 5.0 g of thermoplastic resin pellets (for example, a thermoplastic resin strand extruded with a diameter of 1.5 mm and cut into 2 mm lengths) and 150 mL of a 1% by mass aqueous sodium hydroxide solution are sealed in a pot compatible with a rotary pot dyeing tester (for example, the "MINICOLOR" dyeing tester manufactured by Texam Giken Co., Ltd.), and the pot is set in the rotary pot dyeing machine. (2) The temperature of the pot is raised to 80°C at a rate of 3°C / min while stirring at a rotation speed of 30 rpm, and once 80°C is reached, the temperature is maintained at 30 rpm for 30 minutes. (3) After 30 minutes have passed, immediately remove the pot from the testing machine and cool it in water. After that, remove the remaining thermoplastic resin from the pot and dry it in a hot air oven at 110°C for 15 minutes, and measure the mass after drying. (4) Round the value calculated from the following formula 6 to the nearest whole number. Dissolution rate (g / h) = (5.0 - (mass of thermoplastic resin remaining without dissolution)) × 2 (Equation 6).

[0053] And, thermoplastic resin P soluble in alkaline aqueous solution A1 Examples of such a copolymer include a copolymer containing polyethylene terephthalate, 5-sodium sulfoisophthalic acid, and polyethylene glycol as repeating units (hereinafter, sometimes referred to as SSIA-PEG copolymerized PET), and polylactic acid. In particular, SSIA-PEG copolymerized PET, which has a melting point of 260°C or less, is preferred because it is easy to make ultrafine fibers by the melt-blowing method and it is easy to control the fiber diameter of the fibers that make up the final nonwoven fabric.

[0054] In addition, thermoplastic resin P, which is insoluble in alkaline aqueous solution, B1 The thermoplastic resin is one that will become the thermoplastic resin of the fibers that make up the final nonwoven fabric, and is preferably one of those mentioned above.

[0055] In addition, thermoplastic resin P, which is insoluble in alkaline aqueous solution, B1 The zero shear viscosity at 230°C is preferably 50 Pa·s or more and 500 Pa·s or less. By making the zero shear viscosity preferably 50 Pa·s or more, more preferably 55 Pa·s or more, the thermoplastic resin P A1 This improves the dispersibility of the polymer in the fiber, making it easier to control the structure of the final nonwoven fabric. Furthermore, by setting the zero shear viscosity to preferably 500 Pa s or less, and more preferably 450 Pa s or less, the pressure loss in the spinneret during the spinning process can be reduced, resulting in a raw material with excellent processability.

[0056] In the present invention, the thermoplastic resin P is insoluble in an alkaline aqueous solution. B1 The zero shear viscosity refers to a value measured and calculated as follows. (1) Thermoplastic resin P that is insoluble in alkaline aqueous solution B1 The amount to be sampled should be sufficient to fill the space between the parallel plates of the rheometer described below, i.e., sufficient to fill a cylinder with a base radius of 10 mm and a height of 0.5 mm. This amount should be at least 0.15 g and adjusted according to the specifications of the measuring device. (2) Using a rheometer (for example, "Reosol G3000" manufactured by UBM Corporation), set the parallel plates on which the above test pieces are set, and measure the melt viscosity when strain is applied at angular frequencies of 1.26 rad / sec, 3.14 rad / sec, 6.28 rad / sec, 12.57 rad / sec, 31.42 rad / sec, and 62.83 rad / sec. (3) The relationship between angular frequency and melt viscosity is linearly approximated for the results obtained from the two test pieces. (4) The melt viscosity value calculated by extrapolating the linear approximation to 0 rad / sec is defined as the zero shear viscosity.

[0057] In addition, the thermoplastic resin P soluble in an alkaline aqueous solution in the raw material resin used in the method for producing the nonwoven fabric of the present invention A1 The mass fraction of the thermoplastic resin P soluble in an alkaline aqueous solution is preferably 60% by mass or more and 95% by mass or less. A1 By setting the mass fraction of the structure-forming resin to be preferably 60 mass % or more, more preferably 65 mass % or more, and even more preferably 70 mass % or more, it becomes easier to disperse the structure-forming resin and to control the structure of the final nonwoven fabric. A1 By setting the mass fraction of the nonwoven fabric to preferably 95% by mass or less, more preferably 93% by mass or less, and even more preferably 90% by mass or less, productivity of the nonwoven fabric is improved.

[0058] The raw material resin used in the method for producing the nonwoven fabric of the present invention includes a thermoplastic resin P B1 In order to improve the dispersibility of the thermoplastic resin P A1 and thermoplastic resin P B1 Thermoplastic resin P that is compatible with both B2 For example, the thermoplastic resin P A1 SSIA-PEG copolymer PET, thermoplastic resin P B1 When polypropylene is used as the thermoplastic resin P B2 Examples of suitable thermoplastic resins include acid-modified polyolefins such as maleic anhydride-modified polypropylene (for example, various types of "UMEX (registered trademark)" manufactured by Sanyo Chemical Industries, Ltd.), and compatibilizer masterbatch "MARICON (registered trademark)" manufactured by Osaka Gas Chemicals Co., Ltd. B2 The mass fraction of the thermoplastic resin P is preferably 0.1% by mass or more and 10% by mass or less of the total raw materials. B1 It is preferable to appropriately adjust the mass fraction of the catalyst.

[0059] Furthermore, various additives may be added to the raw material resin used in the method for producing the nonwoven fabric of the present invention, within the scope of not impairing the effects of the present invention, such as inorganic substances such as titanium oxide, silica, barium oxide, calcium carbonate, carbon black, colorants such as dyes and pigments, flame retardants, fluorescent brighteners, antioxidants, charge stabilizers, antistatic agents, or ultraviolet absorbers.

[0060] In the method for producing the nonwoven fabric of the present invention, it is preferable that the raw material resin is obtained by kneading all of the thermoplastic resins constituting the raw material resin in an extruder with two or more screws. A1 Thermoplastic resin P B1 This is preferable because the components are well dispersed and the structure of the final nonwoven fabric can be easily controlled. The twin or more screw extruder used in this case may be directly connected to the spinning machine.

[0061] (a-2) Melt spinning The spinneret used in the melt spinning in this process preferably has multiple discharge holes. The shapes of the discharge holes that can be used include round, triangular, rectangular, and Y-shaped. Round discharge holes are preferred because they provide excellent process stability during the spinning process. In the case of round discharge holes, their diameter is preferably 0.08 mm or more and 1.0 mm or less. Setting the diameter of the discharge holes to preferably 0.08 mm or more, more preferably 0.10 mm or more, reduces the risk of hole clogging and improves productivity. Setting the diameter of the discharge holes to preferably 1.0 mm or less, more preferably 0.70 mm or less, and even more preferably 0.50 mm or less improves the distribution of the resin within the spinneret, enabling the production of a uniform nonwoven fabric.

[0062] The spinning temperature in the melt spinning in this step, i.e., the temperature of the discharge surface of the spinneret, is preferably set to (the melting temperature of the resin with the highest melting point among the resins contained in the raw material resins + 30°C) or higher (the melting temperature of the resin with the highest melting point among the resins contained in the raw material resins + 100°C). For example, in the case of thermoplastic resin P A1 As a result, SSIA-PEG copolymer PET with a melting point of 230°C, thermoplastic resin P B1 When polypropylene with a melting point of 160°C is used as the spinning material, the spinning temperature is preferably set to approximately 260°C or higher and 330°C or lower. By setting the spinning temperature at or above (the melting temperature of the resin with the highest melting point among the resins contained in the raw material resins + 30°C), the viscosity of the spun raw material resin decreases, and the production of ultra-thin fibers is promoted. Furthermore, by setting the spinning temperature at or below (the melting point of the resin with the highest melting point among the resins contained in the raw material resins + 100°C), and more preferably at or below (the melting point of the resin with the highest melting point among the resins contained in the raw material resins + 80°C), thermal decomposition and hydrolysis of the raw material resin in the spinning machine are suppressed, and spinnability is improved.

[0063] Examples of spinning methods used in the melt spinning in this step include melt-blowing and spunbonding. Among these, the melt-blowing method is preferred because it is a spinning method suitable for making ultra-thin fibers and because a fiber sheet is formed by self-fusion of the fibers simultaneously with collection, eliminating the need for a step such as thermal bonding. A preferred embodiment of the melt-blowing method as the spinning method will be described below.

[0064] When melt-blowing is used in the melt spinning of this process, the hot air temperature is preferably between (spinning temperature - 10°C) and (spinning temperature + 10°C) relative to the spinning temperature. By setting the hot air temperature between (spinning temperature - 10°C) and (spinning temperature + 10°C), and more preferably between (spinning temperature - 5°C) and (spinning temperature + 5°C), the change in viscosity of the raw resin immediately after extrusion is suppressed, improving spinnability. However, the hot air temperature here refers to the temperature of the hot air measured at a position 5 mm upstream from the hot air outlet surface in the direction of the hot air flow path.

[0065] When the melt-blowing method is used in the melt spinning process in this step, the hot air pressure is preferably 0.01 MPa or more and 0.40 MPa or less. Setting the hot air pressure to preferably 0.01 MPa or more, more preferably 0.03 MPa or more, and even more preferably 0.05 MPa or more promotes ultra-thin fibers. Setting the hot air pressure to preferably 0.40 MPa or less, more preferably 0.30 MPa or less, and even more preferably 0.20 MPa or less makes it difficult for fibers to become thick or thin, resulting in a fiber sheet with good texture. Note that the hot air pressure referred to here refers to the pressure of the hot air measured at a position 5 mm upstream from the hot air outlet surface in the direction of the hot air flow path.

[0066] (a-3) Collection of spun yarn Furthermore, the spun yarn obtained by the melt spinning is collected in a collecting device below to form a fiber sheet.

[0067] In this step, the distance from the spinneret to the collector is preferably 3 cm or more and 100 cm or less. By making the distance from the spinneret to the collector preferably 3 cm or more, more preferably 5 cm or more, and even more preferably 10 cm or more, the elastic modulus of the fiber sheet can be improved. Furthermore, by making the distance preferably 100 cm or less, more preferably 80 cm or less, and even more preferably 50 cm or less, a fiber sheet with good texture can be obtained, and the quality of the final nonwoven fabric can also be improved.

[0068] The collection device in this process has the function of collecting and transporting fibers by generating negative pressure using a blower or the like installed directly below a mesh structure made of metal or synthetic resin, and examples of such devices include conveyor-type and drum-type devices.

[0069] (b) Thermoplastic resin P A1 Eluting In this step, the thermoplastic resin P of the fiber sheet obtained in the previous step A1 is eluted by treatment with an alkaline aqueous solution.

[0070] The alkaline aqueous solution referred to here refers to an aqueous solution having a pH of 10.0 or higher, and examples of solutes include sodium hydroxide, potassium hydroxide, etc. As such an aqueous solution, a sodium hydroxide aqueous solution having a concentration of 0.1% by mass or more and 4.0% by mass or less is preferably used.

[0071] In the method for producing the nonwoven fabric of the present invention, the thermoplastic resin P A1 The processing temperature when dissolving the thermoplastic resin P A1 (glass transition temperature of thermoplastic resin P + 10°C) or higher, B1 For example, the melting point of the thermoplastic resin P is preferably 40°C or less. A1 SSIA-PEG copolymer PET, thermoplastic resin P B1When polypropylene is used as the thermoplastic resin, the treatment temperature is preferably in the range of about 60°C to 120°C, and particularly preferably in the range of 75°C to 100°C. A1 The glass transition temperature of the thermoplastic resin P is set at 10°C or higher. A1 The thermoplastic resin P can be easily dissolved, improving productivity. B1 By setting the melting temperature of the thermoplastic resin P at -40°C or lower, B1 This prevents the polymer from melting, and the breathability and water pressure resistance of the final nonwoven fabric are not impaired.

[0072] In this step, methods for treating the fiber sheet with an alkaline aqueous solution include immersing the fiber sheet in an alkaline aqueous solution, spraying the alkaline aqueous solution onto the fiber sheet at high pressure, etc. Among these, immersing the fiber sheet in an alkaline aqueous solution allows the entire fiber sheet to be treated uniformly, thereby producing a high-quality nonwoven fabric.

[0073] In this process, the fiber sheet is treated with an alkaline aqueous solution to form a thermoplastic resin P A1 After dissolving the thermoplastic resin P, it is preferable to immerse the sheet in water. By doing so, the alkaline aqueous solution remaining in the sheet and the dissolved thermoplastic resin P can be removed. A1 In particular, it is a preferred embodiment to include a washing step in addition to the immersion in water. By including a washing step by spraying water on the thermoplastic resin P at the same time as the immersion, the thermoplastic resin P A1 This allows for more efficient removal of the oxidizing agent, and the contact angle of the final nonwoven fabric with water is improved, resulting in a nonwoven fabric with excellent water pressure resistance.

[0074] In the method for producing a nonwoven fabric of the present invention, methods for removing moisture from a sheet treated with an alkaline aqueous solution include air drying at room temperature, suction removal of remaining water while conveying the sheet on a suction conveyor, hot air treatment to evaporate water, and a combination of suction by a suction conveyor and hot air treatment. Among these, when hot air treatment is performed, the hot air temperature is preferably 50°C or higher and 110°C or lower. Setting the hot air temperature to 50°C or higher allows the sheet to be dried efficiently, improving productivity. On the other hand, setting the hot air temperature to 110°C or lower prevents fusion of the fibers constituting the sheet, thereby maintaining the breathability of the final nonwoven fabric.

[0075] (c) Finishing process (electret processing, post-processing) In the method for producing a nonwoven fabric of the present invention, the sheet that has undergone the above steps may be used as a nonwoven fabric as is, but it is also preferable to subject the sheet to various finishing steps, as in the general method for producing a nonwoven fabric, to produce a nonwoven fabric. Of course, the sheet obtained by these finishing steps is also considered to be a nonwoven fabric of the present invention.

[0076] The nonwoven fabric manufacturing method of the present invention can also be subjected to electret processing. Electret processing improves dust collection performance when used as a waterproof layer in protective clothing. Specifically, for example, a method (corona discharge method) can be used in which the sheet obtained in the above process is placed in contact with a ground electrode, and while the ground electrode and the fiber sheet are moved together, high voltage is applied using a non-contact voltage application electrode to continuously perform electret processing to obtain a nonwoven fabric. Alternatively, a method (hydrocharge method) can be used in which the sheet obtained in the above process is electretized by spraying a jet or a stream of water droplets onto the sheet obtained in the above process at a pressure sufficient to penetrate the interior of the fiber sheet, thereby obtaining a nonwoven fabric with a uniform mixture of positive and negative charges. Of these methods, the corona discharge method is preferred because it allows for efficient electretization.

[0077] In the method for producing a nonwoven fabric of the present invention, post-processing such as water-repellent processing and pleating can also be carried out depending on the intended use of the nonwoven fabric.

[0078] [Laminate] Because the nonwoven fabric of the present invention has the above-mentioned properties, another preferred embodiment is a laminate containing the nonwoven fabric. Examples of laminate structures include a structure in which a spunbonded nonwoven fabric is laminated on both sides of the nonwoven fabric of the present invention (a spunbonded nonwoven fabric / nonwoven fabric of the present invention / spunbonded nonwoven fabric structure; hereinafter, this may be referred to as an SMS structure), and a structure in which a woven or knitted fabric is laminated on both sides of the nonwoven fabric of the present invention. Laminates with an SMS structure are suitable for use as protective clothing, and laminates with a structure in which a woven or knitted fabric is laminated on both sides of the nonwoven fabric of the present invention are suitable for use as breathable, waterproof outdoor clothing.

[0079] When laminating a spunbonded nonwoven fabric and the nonwoven fabric of the present invention, from the viewpoint of improving the quality of the laminate, it is preferable to perform the lamination offline (producing the spunbonded nonwoven fabric and the nonwoven fabric of the present invention separately and laminating them together).

[0080] Methods for bonding a spunbond nonwoven fabric to the nonwoven fabric of the present invention include thermal bonding using various rolls, such as a heat embossing roll, each of which has an engraved (uneven) surface on a pair of upper and lower rolls, a heat embossing roll consisting of a combination of one roll with a flat (smooth) surface and the other with an engraved (uneven) surface, and a heat calender roll consisting of a combination of upper and lower flat (smooth) rolls, as well as ultrasonic bonding, which involves thermal welding using ultrasonic vibrations from a horn. Among these, the use of a heat embossing roll, each of which has an engraved (uneven) surface on a pair of upper and lower rolls, or a heat embossing roll consisting of a combination of one roll with a flat (smooth) surface and the other with an engraved (uneven) surface, is preferred because of its excellent productivity, ability to impart strength to the partial thermally bonded areas, and ability to maintain moisture permeability in areas other than the partial thermally bonded areas (non-bonded areas).

[0081] The surface material of the hot embossing roll is preferably made of metal in order to obtain a sufficient thermal adhesion effect and to prevent the engraving (concave and convex portions) of one embossing roll from being transferred to the surface of the other roll.

[0082] The embossed adhesion area ratio using such a hot embossing roll is preferably 3% or more and 30% or less. By making the embossed adhesion area ratio preferably 3% or more, more preferably 5% or more, and even more preferably 8% or more, it is possible to obtain mechanical properties such as tensile strength, tear strength, and fluff resistance that are practical for use as a laminated nonwoven fabric. On the other hand, by making the embossed adhesion area ratio preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less, it is possible to ensure breathability. Even when using a bonding method such as ultrasonic bonding, it is preferable that the embossed adhesion area ratio be in a similar range.

[0083] The embossed bond area ratio here refers to the proportion of the thermally bonded area in the entire laminated nonwoven fabric. Specifically, when thermal bonding is performed using a pair of uneven rolls, it refers to the proportion of the area in the entire laminated nonwoven fabric where the convex parts of the upper roll and the convex parts of the lower roll overlap and abut the nonwoven fabric layer (thermally bonded area). When thermal bonding is performed using an uneven roll and a flat roll, it refers to the proportion of the area in the entire laminated nonwoven fabric where the convex parts of the uneven roll abut the nonwoven fabric layer (thermally bonded area). Furthermore, when ultrasonic bonding is performed, it refers to the proportion of the area in the entire laminated nonwoven fabric that is thermally welded by ultrasonic processing (thermally bonded area).

[0084] The shapes of the thermally bonded portions formed by the hot embossing roll or ultrasonic bonding can be circular, elliptical, square, rectangular, parallelogram, rhombus, regular hexagon, regular octagon, etc. Furthermore, it is preferable that the thermally bonded portions are uniformly spaced at regular intervals in the longitudinal direction (machine direction) and width direction of the laminated nonwoven fabric. This reduces the variation in strength of the laminated nonwoven fabric.

[0085] The surface temperature of the hot embossing roll during thermal bonding is preferably between (the melting point of the resin used - 50°C) and (the melting point of the resin used - 15°C). By setting the surface temperature of the hot embossing roll to be preferably at least -50°C, more preferably at least -45°C, higher than the melting point of the resin used, a laminated nonwoven fabric with practically acceptable mechanical properties, such as tensile strength, tear strength, and fluff resistance, can be obtained. Furthermore, by setting the surface temperature of the hot embossing roll to be preferably at most -15°C, more preferably at most -20°C, higher than the melting point of the resin used, excessive thermal bonding can be suppressed, and a highly breathable laminated nonwoven fabric can be obtained.

[0086] In addition, when the nonwoven fabric of the present invention contains two or more raw materials and two or more melting points are observed, it is preferable to adjust the temperature so that the lowest of the observed melting points is within the above range.

[0087] The linear pressure of the hot embossing roll during thermal bonding is preferably 10 N / cm or more and 500 N / cm or less. By setting the roll linear pressure to preferably 10 N / cm or more, more preferably 50 N / cm or more, even more preferably 100 N / cm or more, and even more preferably 150 N / cm, a laminated nonwoven fabric with practically usable mechanical properties such as tensile strength, tear strength, and fluff resistance can be obtained. On the other hand, by setting the linear pressure of the hot embossing roll to preferably 500 N / cm or less, more preferably 400 N / cm or less, and even more preferably 300 N / cm or less, a laminated nonwoven fabric with excellent breathability and flexibility can be obtained.

[0088] In the present invention, in order to adjust the thickness of the laminated nonwoven fabric, thermocompression bonding can be performed using a thermal calender roll consisting of a pair of upper and lower flat rolls before and / or after thermal bonding using the above-mentioned thermal embossing roll. The pair of upper and lower flat rolls refers to metal rolls or elastic rolls with smooth surfaces, and is configured by pairing two metal rolls or two metal rolls, or by pairing a metal roll and an elastic roll.

[0089] The elastic roll in the present invention refers to a roll made of a material having higher elasticity than a metal roll, and examples thereof include paper rolls made of paper, cotton, aramid paper, etc., and resin rolls made of urethane resin, epoxy resin, silicone resin, polyester resin, hard rubber, and mixtures of these.

[0090] Furthermore, when the nonwoven fabric of the present invention is laminated with a woven or knitted fabric, it is preferable to laminate the fabric offline from the viewpoint of improving the quality of the laminate.

[0091] When the nonwoven fabric of the present invention is bonded to a woven or knitted fabric, methods include laminating the layers or bonding the layers together using an adhesive such as a hot-melt adhesive. When bonding the layers together using a hot-melt adhesive, the bonding area ratio is preferably 3% or more and 30% or less. By setting the bonding area ratio to preferably 3% or more, more preferably 5% or more, and even more preferably 8% or more, the laminated nonwoven fabric can achieve mechanical properties such as tensile strength and tear strength sufficient for practical use. On the other hand, by setting the bonding area ratio to preferably 30% or less, more preferably 25% or less, and even more preferably 20% or less, breathability and moisture permeability can be ensured.

[0092] The laminate of the present invention may be provided with a functional agent, which may include, but is not limited to, a hydrophilic agent, a water repellent, an oil repellent, an antistatic agent, an antibacterial agent, an antiviral agent, a deodorizer, an aromatic agent, a cooling agent, and the like.

[0093] The method for applying the functional agent is not particularly limited, and for example, impregnation, spraying, kiss roll, etc. can be used.

[0094] [Clothing, miscellaneous goods] The nonwoven fabric of the present invention has high water pressure resistance and excellent breathability and moisture permeability, making it suitable for use as a water-resistant layer in clothing such as protective clothing and breathable, waterproof wear for outdoor sports. Examples of such clothing include tops such as T-shirts, polo shirts, dress shirts, blouses, wrap tops, cut-and-sew tops, sweaters, vests, hoodies, sweatshirts, turtlenecks, cardigans, tank tops, and tube tops; outerwear such as coats, blazers, jackets, windbreakers, cloaks, capes, aprons, and mantles; trousers such as slacks, jeans, and shorts; skirts; dresses such as cocktail dresses, one-piece dresses, and gowns; formal wear, suits, uniforms, and underwear. It is preferable that at least a portion of the front, back, sleeves, collar, facing, hem, inseam, and lining of these garments, or at least a portion of the clothing materials and accessories such as buttons, interlining, and pockets, be made of the nonwoven fabric.

[0095] Furthermore, miscellaneous goods containing the nonwoven fabric are also one of the preferred embodiments, such as shoes and gloves.

[0096] Examples of the shoes include trekking shoes, hiking shoes, sneakers, pumps, loafers, boots, and spikes. Preferably, at least a portion of the upper, lining, insole, etc. of such shoes is made of the nonwoven fabric. [Example]

[0097] The present invention will now be described in detail with reference to examples, although the present invention is not limited to these examples.

[0098] [Measurement method] The values ​​of the various properties in the examples were determined by the following methods. In addition, unless otherwise specified, the measurements of the various physical properties were carried out according to the above methods.

[0099] (1) Number average fiber diameter (μm), weight average fiber diameter (μm), fiber diameter distribution (-), percentage of fibers with a fiber diameter of 100 nm or more and 5000 nm or less (%), percentage of fibers with a fiber diameter of 10 nm or more and 5000 nm or less (%) The scanning electron microscope used was the "S-5500" manufactured by Hitachi High-Technologies Corporation, and measurements and calculations were carried out as described above.

[0100] (2) Weight (g / m 2 ), porosity (%) A 250mm x 250mm square was cut out from the nonwoven fabric, excluding a 30mm area at the edge, and weighed. 2 The value converted into the weight per unit area was rounded to the nearest whole number to obtain an integer, which was used as the basis weight of the nonwoven fabric.

[0101] (3) Zero shear viscosity of nonwoven fabric at 230°C The rheometer used was "Reosol G3000" manufactured by UBM Corporation, and measurements were carried out as described above using parallel plates with a diameter of 20 mm.

[0102] (4) Presence or absence of an endothermic peak in the range of 30.0°C to 125.0°C As a differential scanning calorimeter (DSC), a "DSC6200" manufactured by Seiko Instruments Inc. was used, and measurements and calculations were carried out as described above.

[0103] (5) Tear strength of nonwoven fabric (N) Measurements were carried out using an Elmendorf tear tester "DA-3200" manufactured by Daiei Scientific Instruments Manufacturing Co., Ltd., based on the "D method (pendulum method)" described in JIS L1092:2010 "8.17 Tear strength."

[0104] (6) Breathability of nonwoven fabric (cm 3 / (cm 2 ·sec)) Measurements were carried out using the breathability evaluation device "FX3340" manufactured by Textest Co., Ltd., based on "Method A (Fragile method)" described in "8.26 Breathability" of JIS L1096:2010 "Testing methods for woven and knitted fabrics."

[0105] (7) Water pressure resistance of laminate (mmH2O) The nonwoven fabrics obtained in the examples and comparative examples were coated on both sides with a polypropylene resin sheet having an average single fiber diameter of 16.5 μm and a basis weight of 30 g / m 2A spunbond nonwoven fabric that had been heat-embossed at a linear pressure of 100 N / cm (embossed bond area ratio: 12%, thermally bonded area shape: round) was laminated on the nonwoven fabric, and then heat-embossed at a temperature of 110°C (90°C for the nonwoven fabrics of Examples 11 to 13 using polyethylene resins A to C) at a linear pressure of 100 N / cm (embossed bond area ratio: 15%, thermally bonded area shape: diamond) to obtain an SMS laminate. The water pressure resistance of the laminate was measured and calculated using a water pressure resistance evaluation device "FX3000-IV" manufactured by Textest Co., Ltd., based on "Method A (low water pressure method)" described in "7.1. Water resistance test (hydrostatic pressure method)" of JIS L1092:2009, "Testing methods for waterproofness of textile products." However, if the measured value exceeded 2000 mmH2O, the measurement was repeated based on "Method B (high water pressure method)" and the measurement result based on "Method B" was used as the water pressure resistance of the laminate.

[0106] [Raw material resin] In Examples 1 to 13 and Comparative Examples 1 to 3, the thermoplastic resins used to obtain the raw material resins are as follows. Polypropylene resin A (referred to as "PP-A" in Tables 1 to 3): "E3155E5" manufactured by Exxonmobil Corporation Polypropylene resin B (referred to as "PP-B" in Tables 1 to 3): "H7900" manufactured by LG Chemicals Polypropylene resin C (referred to as "PP-C" in Tables 1 to 3): "H7700" manufactured by LG Chemicals Polypropylene resin D (referred to as "PP-D" in Tables 1 to 3): "HP552R" manufactured by Lyondell Basell Polypropylene resin E (referred to as "PP-E" in Tables 1 to 3): "S10CL" manufactured by Prime Polymer Co., Ltd. Polyethylene resin A (referred to as "PE-A" in Tables 1 to 3): "ASPUN 6850" manufactured by Dow Chemical Company Polyethylene resin B (referred to as "PE-B" in Tables 1 to 3): "EL-Lene" manufactured by SCG Polyethylene resin C (referred to as "PE-C" in Tables 1 to 3): USI "LH5590" Polylactic acid resin (referred to as "PLA" in Table 1): Nature Works polylactic acid "6202D" ( SSIA-PEG copolymerized PET resin (referred to as "easily eluting PET" in Tables 1 to 3): A copolymer was used in which the repeating unit molar fraction was 83.0 mol% polyethylene terephthalate, 8.0 mol% 5-sodium sulfoisophthalic acid, and 9.0 mol% polyethylene glycol. The melting point and zero shear viscosity at 290°C of this SSIA-PEG copolymerized PET resin were measured, and the melting point was found to be 230°C, and the zero shear viscosity at 290°C was 350 Pa s. Compatibilizer resin α (referred to as "COM-α" in Tables 1 and 2): "UMEX 5200" manufactured by Sanyo Chemical Industry Co., Ltd. Compatibilizer resin β (referred to as "COM-β" in Table 1): Compatibilizer masterbatch for composite materials "Maricon J10000MB-G" manufactured by Osaka Gas Chemicals Co., Ltd. [Example 1] (Step of forming a fiber sheet) First, chips of polypropylene resin A, SSIA-PEG copolymerized PET resin, and compatibilizer resin α were dry-blended in a mass ratio of 20:78:2. These were fed into a twin-screw extruder with a shaft diameter D of 10 mm and a shaft length L of 30 mm at a rate of 30 g / min and kneaded at 290°C and a screw rotation speed of 300 rpm to obtain the raw resin.

[0107] Next, the obtained raw resin was extruded from a die with a hole diameter of 0.4 mm, 151 holes, and a hole pitch of 1 mm at a single-hole discharge rate of 0.2 g / min, and spun in a melt-blown spinning machine under conditions of a spin block temperature of 290°C, a hot air temperature of 320°C, and a hot air pressure of 0.15 MPa to obtain a fiber sheet.

[0108] (Thermoplastic resin P A1 (a step of eluting the This fiber sheet was immersed in a 1.0% by mass aqueous sodium hydroxide solution at 90°C for 60 minutes to elute the SSIA-PEG copolymerized PET resin. After elution, the sheet was washed with water and dried by blowing hot air at 90°C onto the sheet. The sheet was then dried to a basis weight of 20 g / m. 2 The results are shown in Table 1.

[0109] [Example 2] A sieve having a basis weight of 20 g / m was prepared in the same manner as in Example 1, except that polypropylene resin A was changed to polypropylene resin B. 2 The results are shown in Table 1.

[0110] [Example 3] A sieve having a basis weight of 20 g / m was prepared in the same manner as in Example 1, except that polypropylene resin A was changed to polypropylene resin C. 2 The results are shown in Table 1.

[0111] [Example 4] A 20 g / m2 PET film was prepared in the same manner as in Example 1, except that the mass ratio of polypropylene resin A, SSIA-PEG copolymerized PET resin, and compatibilizer resin α was changed to 5:94:1. 2 The results are shown in Table 1.

[0112] [Example 5] A sieve having a basis weight of 20 g / m was obtained by the same method as in Example 1, except that the mass ratio of polypropylene resin A, SSIA-PEG copolymerized PET resin, and compatibilizer resin α was changed to 10:89:1 and drying was performed by suction using a suction conveyor. 2 The results are shown in Table 1.

[0113] [Example 6] A 20 g / m2 PET film was prepared in the same manner as in Example 1, except that the mass ratio of polypropylene resin A, SSIA-PEG copolymerized PET resin, and compatibilizer resin α was changed to 30:67:3. 2 The results are shown in Table 1.

[0114] [Example 7] A fiber sheet having a basis weight of 20 g / m was prepared in the same manner as in Example 1, except that the treatment temperature and time in the step of treating the fiber sheet with an aqueous sodium hydroxide solution were changed to 25°C and 24 hours, respectively. 2 The results are shown in Table 1.

[0115] [Example 8] A sieve having a basis weight of 20 g / m was prepared in the same manner as in Example 1, except that the compatibilizer α was changed to the compatibilizer β. 2 The results are shown in Table 2.

[0116] [Example 9] A sieve having a basis weight of 20 g / m was prepared in the same manner as in Example 5, except that the compatibilizer α was changed to the compatibilizer β. 2 The results are shown in Table 2.

[0117] [Example 10] (Step of forming a fiber sheet) First, chips of polypropylene resin A and polylactic acid resin dry blended in a mass ratio of 10:90 were fed into a twin-screw extruder with a screw diameter D of 10 mm and L / D of 30 at a rate of 30 g / min, and kneaded at 260°C and a screw rotation speed of 300 rpm to obtain the raw material resin.

[0118] Next, the obtained raw resin was extruded from a die with a hole diameter of 0.4 mm, 151 holes, and a hole pitch of 1 mm at a single-hole output rate of 0.2 g / min, and spun in a melt-blown spinning machine under conditions of a spin block temperature of 260°C, a hot air temperature of 280°C, and a hot air pressure of 0.15 MPa to obtain a fiber sheet.

[0119] (Thermoplastic resin P A1 (a step of eluting the This fiber sheet was immersed in a 1.0% by mass aqueous sodium hydroxide solution at 90°C for 120 minutes to elute the SSIA-PEG copolymerized PET resin. After elution, the sheet was washed with water and dried by blowing hot air at 90°C onto the sheet. The sheet was then dried to a basis weight of 20 g / m. 2 The results are shown in Table 2.

[0120] [Example 11] (Step of forming a fiber sheet) First, chips of polyethylene resin A, SSIA-PEG copolymerized PET resin, and compatibilizer resin α were dry-blended in a mass ratio of 10:87:3. These were fed into a twin-screw extruder with a shaft diameter D of 10 mm and a shaft length L of 30 mm at a rate of 30 g / min and kneaded at 290°C and a screw rotation speed of 300 rpm to obtain the raw resin.

[0121] Next, the obtained raw resin was extruded from a die with a hole diameter of 0.4 mm, 151 holes, and a hole pitch of 1 mm at a single-hole discharge rate of 0.2 g / min, and spun in a melt-blown spinning machine under conditions of a spin block temperature of 290°C, a hot air temperature of 320°C, and a hot air pressure of 0.15 MPa to obtain a fiber sheet.

[0122] (Thermoplastic resin P A1 (a step of eluting the This fiber sheet was immersed in a 1.0% by mass aqueous sodium hydroxide solution at 75°C for 100 minutes to elute the easily eluted resin A. After elution, the sheet was washed with water and dried with hot air at 60°C, resulting in a basis weight of 20 g / m 2 The results are shown in Table 2.

[0123] [Example 12] A woven fabric having a basis weight of 20 g / m was prepared in the same manner as in Example 11, except that polyethylene resin A was changed to polyethylene resin B. 2 The results are shown in Table 2.

[0124] [Example 13] A woven fabric having a basis weight of 20 g / m was prepared in the same manner as in Example 11, except that polyethylene resin A was changed to polyethylene resin C. 2 The results are shown in Table 2.

[0125] [Comparative Example 1] A sieve having a basis weight of 20 g / m was prepared in the same manner as in Example 1, except that polypropylene resin A was changed to polypropylene resin D. 2The results are shown in Table 3.

[0126] Comparative Example 2 A sieve having a basis weight of 20 g / m was prepared in the same manner as in Example 1, except that polypropylene resin A was changed to polypropylene resin E. 2 The results are shown in Table 3.

[0127] Comparative Example 3 Polypropylene resin E was extruded from a die with a hole diameter of 0.12 mm, 151 holes, and a hole pitch of 0.4 mm at a single hole output rate of 0.1 g / min, and subjected to the melt-blowing method under the conditions of a spin block temperature of 290°C, a hot air temperature of 320°C, and a hot air pressure of 0.15 MPa, resulting in a basis weight of 20 g / m 2 The results are shown in Table 3.

[0128] [Table 1]

[0129] [Table 2]

[0130] [Table 3]

[0131] As shown in Tables 1 and 2, the nonwoven fabrics described in the Examples have high water pressure resistance and breathability, as well as excellent tear strength. In contrast, as shown in Table 3, the nonwoven fabric of Comparative Example 1 has high water pressure resistance and breathability, but poor tear strength. Furthermore, the nonwoven fabrics of Comparative Examples 2 and 3 have excellent tear strength, but are nonwoven fabrics with low water pressure resistance.

Claims

1. A nonwoven fabric made of fibers made of a thermoplastic resin, The number average fiber diameter of the fibers is 10 nm or more and 500 nm or less, The nonwoven fabric is The ratio of fibers having a fiber diameter of 100 nm or more and 5000 nm or less is 5% or more and 50% or less, The proportion of fibers having a fiber diameter of 10 nm or more and 5000 nm or less is 99% or more, moreover, The zero shear viscosity at 230 ° C. is 50.0 Pa s or more and 500.0 Pa s or less, Nonwoven fabric.

2. 2. The nonwoven fabric according to claim 1, which has at least one endothermic peak in the range of 30.0°C or higher and 125.0°C or lower in differential scanning calorimetry.

3. 3. The nonwoven fabric according to claim 1, wherein the proportion of fibers having a fiber diameter of 10 nm or more and 100 nm or less is 50% or more and 95% or less.

4. 3. The nonwoven fabric according to claim 1, wherein the fiber diameter distribution of the fibers is 1.50 or more and 3.50 or less.

5. A laminate comprising the nonwoven fabric according to claim 1 or 2.

6. Apparel comprising the laminate of claim 5.

7. Miscellaneous goods comprising the laminate according to claim 5.

8. Thermoplastic resin P soluble in alkaline aqueous solution Ａ１ and, Thermoplastic resin P insoluble in alkaline aqueous solution Ｂ１ and, a step of melt-spinning the raw material resin from the discharge holes of the spinneret and collecting the spun yarn in a collecting device below to form a fiber sheet; The thermoplastic resin P of the fiber sheet Ａ１ a step of treating the compound with an alkaline aqueous solution to elute the compound; A method for producing a nonwoven fabric comprising forming a nonwoven fabric composed of fibers made of a thermoplastic resin, The number average fiber diameter of the fibers is 10 nm or more and 500 nm or less, The nonwoven fabric is The ratio of fibers having a fiber diameter of 100 nm or more and 5000 nm or less is 5% or more and 50% or less, The proportion of fibers having a fiber diameter of 10 nm or more and 5000 nm or less is 99% or more, moreover, The zero shear viscosity at 230 ° C. is 50.0 Pa s or more and 500.0 Pa s or less, Method for manufacturing nonwoven fabric.

9. The raw material resin is the thermoplastic resin P Ａ１ and the thermoplastic resin P Ｂ１ and further, the thermoplastic resin P Ｂ２ The method for producing a nonwoven fabric according to claim 8, comprising:

10. The method for producing a nonwoven fabric according to claim 8 or 9, wherein the raw material resins are obtained by kneading all thermoplastic resins in an extruder having two or more screws.

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