Long-fiber non-woven fabric and method for producing same

Abstract

The present invention relates to a long-fiber non-woven fabric comprising a single-component fiber having a polyester resin as the main component, the long-fiber non-woven fabric being characterized in that: the average value of the weight per unit area of the long-fiber non-woven fabric is 40 g / m2 to 170 g / m2 (inclusive), and the average value of the transmission brightness of the long-fiber non-woven fabric is 150 to 250 (inclusive); the long fiber nonwoven fabric has a coefficient of variation of transmitted light brightness of 5.0% or more and 11.0% or less. Provided is a long-fiber nonwoven fabric which has excellent flexibility and mechanical strength and is suitable for post-processing such as resin processing.

Description

Technical Field

[0001] This invention relates to long fiber nonwoven fabrics. Background Technology

[0002] Due to its excellent balance between performance and cost, long-fiber nonwoven fabrics are widely used not only in applications requiring mechanical strength, such as civil engineering and industrial materials, but also in applications requiring hand feel and softness, such as footwear, bags, clothing, automotive interior materials, interior decoration, and furniture.

[0003] For example, Patent Document 1 describes a nonwoven sheet for civil engineering, which is a nonwoven fabric composed of long fibers formed from thermoplastic synthetic polymers, in which a hydrophilic resin binder is attached and fixed. It describes that this provides a high-strength nonwoven sheet for civil engineering with excellent self-settling properties in water, excellent water layability, and, since the hydrophilic agent is a resin binder, it has an environmentally friendly effect as it is not easily dissolved.

[0004] Furthermore, Patent Document 2 describes an interior decorative surface material, which is an interior decorative surface material formed by laminating nonwoven fabric on the back of a surface sheet using an adhesive formed from thermoplastic resin. The nonwoven fabric is characterized by being composed of cotton fibers, wherein the fibers maintain their shape through three-dimensional interweaving. It is described that this provides an interior decorative surface material with excellent cushioning, moisture absorption, and sound absorption properties.

[0005] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 11-100821 Patent Document 2: Japanese Patent Application Publication No. 2013-252660 Summary of the Invention

[0006] The problem that the invention aims to solve Regarding the nonwoven sheet disclosed in Patent Document 1, in order to achieve its effect, the weight per unit area must be increased and a certain thickness must be achieved. Therefore, although the mechanical strength is excellent, there is a tendency for the transverse rigidity of the nonwoven fabric to become stronger. Furthermore, the softness is not sufficient depending on the application.

[0007] Furthermore, regarding the nonwoven fabric disclosed in Patent Document 2, since there is an adhesive formed from thermoplastic resin on the back side of the surface sheet, there is a problem of high sheet rigidity and poor flexibility.

[0008] Methods for solving problems In order to achieve the above objectives, the inventors of this application have conducted repeated and in-depth research and have obtained the following insights: by making the unit area weight, the average value of transmitted light brightness and its coefficient of variation (CV value) of long fiber nonwoven fabric within a specific range, it is possible to obtain long fiber nonwoven fabric that not only has excellent softness and mechanical strength, but also can be easily processed by resin processing and other post-processing.

[0009] This invention is based on these insights, and the following invention is provided according to this invention.

[0010] [1] Long fiber nonwoven fabric, which is a long fiber nonwoven fabric composed of single-component fibers with polyester resin as the main component, wherein the average unit area weight of the long fiber nonwoven fabric is 40 g / m². 2 Above 170g / m 2 The average transmittance of the long-fiber nonwoven fabric is between 150 and 250, and the coefficient of variation of the transmittance of the long-fiber nonwoven fabric is between 5.0% and 11.0%.

[0011] [2] The long fiber nonwoven fabric as described in [1] above, wherein the average single fiber diameter of the single component fiber is above 8.0 μm and below 20.0 μm.

[0012] [3] The long fiber nonwoven fabric as described in [1] or [2] above, wherein the coefficient of variation of the unit area weight of the long fiber nonwoven fabric is more than 10% and less than 20%.

[0013] [4] The long fiber nonwoven fabric as described in any one of [1] to [3] above, wherein the average thickness of the long fiber nonwoven fabric is more than 0.30 mm and less than 1.20 mm, and the coefficient of variation of the thickness of the long fiber nonwoven fabric is more than 2.0% and less than 8.0%.

[0014] [5] The long-fiber nonwoven fabric as described in any one of [1] to [4] above, wherein the average apparent density of the long-fiber nonwoven fabric is 0.05 g / cm³. 3 Above 0.17g / cm 3 The coefficient of variation for apparent density is between 10.0% and 20.0%.

[0015] [6] The long fiber nonwoven fabric as described in any one of [1] to [5] above, wherein the transverse stiffness of the long fiber nonwoven fabric is more than 40N and less than 500N.

[0016] [7] A method for manufacturing long-fiber nonwoven fabric, wherein the manufacturing method yields a long-fiber nonwoven fabric with an average transmittance of 150 to 250 and a coefficient of variation of transmittance of 5.0% to 11.0%. The method for manufacturing the long-fiber nonwoven fabric includes: The process of forming a single-component fiber with polyester resin as the main component involves melting and extruding a thermoplastic resin with polyester resin as the main component from a spinneret, and then using an ejector to draw and stretch the thermoplastic resin. The process of forming a fiber web, wherein the single-component fibers are stacked on a moving collecting surface; The process of forming a temporary welded sheet includes passing the fiber web through a pair of heated rollers; and The process of mechanically interlacing the temporary welded pieces, The spinning speed during traction is between 3,000 m / min and 6,000 m / min. The surface temperature T of the hot roller S (°C) satisfies the following equation 1, The linear pressure of the hot roller is above 90 N / cm and below 1,000 N / cm. The mechanical weaving is achieved through hydroentangling and / or acupuncture. T m -120≤T S ≤T m -50 (Equation 1) Among them, T m (°C) is the melting point of the polyester resin.

[0017] The effects of the invention According to the present invention, long-fiber nonwoven fabrics with excellent softness, mechanical strength and easy post-processing such as resin processing can be obtained. Detailed Implementation

[0018] The long-fiber nonwoven fabric of the present invention is a long-fiber nonwoven fabric composed of single-component fibers with polyester resin as the main component, and the average weight per unit area of ​​the aforementioned long-fiber nonwoven fabric is 40 g / m². 2 Above 170g / m 2 Hereinafter, the average transmittance of the aforementioned long-fiber nonwoven fabric is 150 to 250, and the coefficient of variation of the transmittance of the aforementioned long-fiber nonwoven fabric is 5.0% to 11.0%. The constituent elements 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 depart from its spirit, and various modifications can be made without departing from the spirit of the present invention.

[0019] [Single-component fibers with polyester resin as the main component] First, the long-fiber nonwoven fabric of the present invention is composed of single-component fibers with polyester resin as the main component. In the fibers of the present invention, "with polyester resin as the main component" means that the polyester resin accounts for more than 50% by mass of the single-component fiber. Furthermore, "single-component fiber" refers to a fiber whose cross-section is substantially occupied by a single component. That is, in the present invention, "single-component fiber with polyester resin as the main component" refers to a fiber formed from a single polyester resin or a fiber composed of a single polyester resin and additives described later. Therefore, composite fibers formed from multiple polyester resins, such as concentric core-sheath type composite fibers, eccentric core-sheath type composite fibers, parallel type composite fibers, or island-island type composite fibers, are excluded from the single-component fibers of the present invention.

[0020] Polyester resins are polymers with acid and glycol components as monomers. In this invention, polyester resin refers to a polyester resin in which the monomer accounts for 80 mol% to 100 mol% of the molar fraction in the repeating unit. In this invention, the acid component can be aromatic carboxylic acids such as phthalic acid (ortho-form), isophthalic acid, and terephthalic acid; aliphatic dicarboxylic acids such as adipic acid and sebacic acid; and alicyclic dicarboxylic acids such as cyclohexane carboxylic acid. Furthermore, the glycol component can be ethylene glycol, diethylene glycol, and polyethylene glycol.

[0021] Specific examples of the aforementioned polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polypropylene terephthalate (PTT), polyethylene naphthalate (PEN), polylactic acid (PLA), and polybutylene succinate (PBS).

[0022] In these polyester resins, additives such as crystallizing nucleating agents, matting agents, pigments, mildew inhibitors, antibacterial agents, flame retardants, metal oxides, aliphatic diamides and / or alkyl-substituted aliphatic monoamides, and hydrophilic agents may be added without impairing the effects of the present invention. Among these, metal oxides such as titanium oxide have the following effects: improving spinnability by reducing surface friction of the fibers and preventing fiber-to-fiber bonding; and improving the bonding properties between fibers constituting the long-fiber nonwoven fabric by increasing thermal conductivity during the welding and forming of the long-fiber nonwoven fabric using hot rollers. Furthermore, aliphatic diamides such as ethylene bis-stearamide and / or alkyl-substituted aliphatic monoamides improve the release properties between the hot roller and the nonwoven web, and improve conveyability.

[0023] Examples of cross-sectional shapes for the single-component fibers of the present invention include circular cross-sections, elliptical cross-sections, capsule-shaped flat cross-sections, polygonal cross-sections such as triangles and quadrilaterals, multi-leaf cross-sections, and hollow cross-sections. Among these, from the viewpoint of ensuring uniform fiber interweaving without excessive fiber cutting during the needle punching process described later, using a circular cross-section is preferred.

[0024] The average single fiber diameter of the single-component fibers of the present invention is preferably 8.0 μm or more and 20.0 μm or less. Regarding the range of this average single fiber diameter, the lower limit is preferably 8.0 μm or more, more preferably 8.5 μm or more, and even more preferably 9.0 μm or more, thereby resulting in a long-fiber nonwoven fabric with superior mechanical strength. On the other hand, regarding the range of the average single fiber diameter, by preferably setting the upper limit to 20.0 μm or less, more preferably 19.5 μm or less, and even more preferably 19.0 μm or less, the uniformity of the long-fiber nonwoven fabric can be improved, forming a long-fiber nonwoven fabric with a dense surface. When resin is impregnated into the long-fiber nonwoven fabric, uneven resin impregnation can be reduced.

[0025] It should be noted that, in this invention, the average single fiber diameter (μm) of the single component fiber is a value obtained by the following method.

[0026] (i) Ten small samples of 10 mm × 10 mm were randomly collected from long fiber nonwoven fabric.

[0027] (ii) Take photographs of the surface of the collected small sample pieces at magnification of 500x to 2,000x using a scanning electron microscope or similar instrument to measure the fiber diameter.

[0028] (iii) Randomly select 10 fibers from the photographs of each small sample, for a total of 100 fibers, and determine their diameters. In cases where the cross-sectional shape of the fiber is not circular, first determine the cross-sectional area of ​​a single fiber, calculate the diameter if the cross-section is considered circular, and then determine the diameter of the single fiber.

[0029] (iv) The average single fiber diameter is calculated by rounding the arithmetic mean (μm) of the above diameters to the second decimal place.

[0030] [Long-fiber nonwoven fabric] The long-fiber nonwoven fabric of the present invention is composed of single-component fibers with the aforementioned polyester resin as the main component. In this invention, "long-fiber nonwoven fabric" refers to long-fiber nonwoven fabric obtained by the manufacturing method described later, and does not include nonwoven fabric (short-fiber nonwoven fabric) composed only of fibers cut to a certain length (e.g., 100 mm).

[0031] Furthermore, in the long-fiber nonwoven fabric of the present invention, "longitudinal direction of the long-fiber nonwoven fabric" refers to the sheet conveying direction during the manufacture of the long-fiber nonwoven fabric, that is, the winding direction of the nonwoven fabric roller, also known as the MD direction. Additionally, "transverse direction of the long-fiber nonwoven fabric" refers to the sheet conveying direction during the manufacture of the long-fiber nonwoven fabric, that is, the direction perpendicular to and intersecting the winding direction of the nonwoven fabric roller, also known as the CD direction. In other words, when the longitudinal direction can be determined from the appearance of the long-fiber nonwoven fabric, that is, when the winding direction of the nonwoven fabric roll can be uniquely determined, this direction is taken as the longitudinal direction, and the direction orthogonal within the surface of the nonwoven fabric is taken as the transverse direction.

[0032] On the other hand, in cases where the long fiber nonwoven fabric is cut or not in a rolled state, and the longitudinal direction cannot be determined based on its appearance, the longitudinal and transverse directions are determined by the following steps.

[0033] (a) In the plane of the long fiber nonwoven fabric, determine any one direction, and collect 5 test pieces with a length of 30 cm and a width of 5.0 cm at equal intervals along that direction.

[0034] (b) Similarly, five test pieces, each 30 cm long and 5.0 cm wide, were collected at equal intervals in directions that were rotated 30, 60, and 90 degrees from the direction of collection.

[0035] (c) For each test piece in each direction, the tensile strength of each test piece was determined based on the method for determining the tensile strength of long-fiber nonwoven fabrics shown in (c-1) to (c-2) below. It should be noted that the tensile strength (N / 5cm) was determined according to 6.3 "Tensile Strength and Elongation" of JIS L1913:2010 "General Test Methods for Long-Fiber Nonwoven Fabrics", using the values ​​measured below.

[0036] (c-1) Apply load until the sample breaks under the conditions of clamping interval of 20cm and tensile speed of 100±10mm / min.

[0037] (c-2) Take the strength of the sample under maximum load as the tensile strength (N / 5cm), calculate the average value of 5 points, and round the first decimal place as the tensile strength of the long fiber nonwoven fabric.

[0038] (d) The direction with the highest measured value is designated as the longitudinal direction of the long-fiber nonwoven fabric, and the direction orthogonal to the longitudinal direction is designated as the transverse direction. Where there are two or more directions with the highest tensile strength, the direction orthogonal to these directions with the lowest tensile strength is designated as the longitudinal direction of the long-fiber nonwoven fabric, and the direction orthogonal to the designated longitudinal direction is designated as the transverse direction. Furthermore, where there are two or more directions with the highest tensile strength, and the tensile strengths in the directions orthogonal to these directions are equal (e.g., all four directions have equal tensile strengths), any one of these four directions is designated as the longitudinal direction, and the direction orthogonal to the designated longitudinal direction is designated as the transverse direction. In any case, it is self-evident that the transverse direction orthogonal to the longitudinal direction exists within the same nonwoven fabric surface, and not in a direction outside the surface.

[0039] Furthermore, regarding the long-fiber nonwoven fabric of the present invention, the average transmittance of the aforementioned long-fiber nonwoven fabric is 150 to 250, and the coefficient of variation of the transmittance of the aforementioned long-fiber nonwoven fabric is 5.0% to 11.0%. By satisfying both of these conditions, not only are the softness and mechanical strength excellent, but also the resin impregnation unevenness can be reduced when the resin is impregnated in the long-fiber nonwoven fabric.

[0040] First, the average transmittance of the aforementioned long-fiber nonwoven fabric of the present invention is 150 to 250. Regarding the range of this average transmittance, by setting its lower limit to 150 or more, preferably 160 or more, and more preferably 170 or more, the monofilaments constituting the long-fiber nonwoven fabric provide adequate resistance when impregnated with resin, thus suppressing impregnation defects. On the other hand, regarding the range of the average transmittance, by setting its upper limit to 250 or less, preferably 240 or less, and more preferably 230 or less, a long-fiber nonwoven fabric with less resin impregnation unevenness is obtained when impregnated with resin.

[0041] Next, the coefficient of variation of the transmitted light intensity of the aforementioned long-fiber nonwoven fabric of the present invention is 5.0% or more and 11.0% or less. Regarding the range of this coefficient of variation of transmitted light intensity, by setting its lower limit to 5.0% or more, preferably 5.5% or more, and more preferably 6.0%, local impregnation unevenness can be suppressed when resin is impregnated. On the other hand, regarding the range of the coefficient of variation of transmitted light intensity, by setting its upper limit to 11.0%, preferably 10.5%, and more preferably 10.0% or less, partial impregnation loss can be suppressed when resin is impregnated.

[0042] It should be noted that, in this invention, the average value and coefficient of variation of the light transmittance of the long fiber nonwoven fabric are values ​​determined by the following steps.

[0043] (i) Cut three 15cm×15cm test pieces from long fiber nonwoven fabric.

[0044] (ii) The test piece is placed on a black drawing paper with an L value of 30.0 or less as measured by a colorimeter (e.g., Konica Minolta Co., Ltd. "CR-20") as a background, and is placed in a scanner (e.g., Seiko Epson Co., Ltd. "GT-X750" etc.).

[0045] (iii) Read in at a resolution of 1,200 dpi by an image scanner.

[0046] (iv) Next, the read image file is processed using image processing software (e.g., "AT-Image Ver. 4.6", which can perform image processing such as binarization and Fourier transform of the information read by the scanner). The average value (arithmetic mean), standard deviation (σ), and coefficient of variation (%) of the transmitted light intensity are calculated, and each value is rounded to the second decimal place. It should be noted that the coefficient of variation (%) of the transmitted light intensity is calculated using the following formula.

[0047] [Coefficient of variation of transmitted light intensity (%)] = [Standard deviation of transmitted light intensity (σ)] / [Average value of transmitted light intensity] × 100 (Equation).

[0048] In addition, in order to make the average value and coefficient of variation of the transmitted light brightness of the aforementioned long fiber nonwoven fabric within the above-mentioned range, it can be achieved by making the average single fiber diameter within the above-mentioned range and using a rectangular ejector, fiber opener, etc., to adjust the unit area weight and thickness to the range described later when forming the fiber web.

[0049] The average weight per unit area of ​​the long-fiber nonwoven fabric of this invention is 40 g / m². 2 Above 170g / m 2 The following is a range for the average weight per unit area, with its lower limit set at 40 g / m². 2 The above is preferably 45g / m 2 The above, more preferably 50g / m 2 This results in a long-fiber nonwoven fabric with excellent mechanical strength. On the other hand, regarding the range of the average weight per unit area mentioned above, its upper limit is set at 170 g / m². 2 The preferred value is 165g / m³. 2 The following is more preferably 160g / m 2 This results in a lightweight and highly maneuverable long-fiber nonwoven fabric.

[0050] Furthermore, the coefficient of variation of the unit area weight of the long-fiber nonwoven fabric of the present invention is preferably 10% or more and 20% or less. Regarding the range of this coefficient of variation, by setting its lower limit to preferably 10% or more, more preferably 11% or more, and even more preferably 12% or more, local impregnation unevenness can be suppressed when resin impregnation is performed. On the other hand, regarding the range of the coefficient of variation, by setting its upper limit to 20%, preferably 19%, and more preferably 18% or less, local impregnation deficiency can be suppressed when resin impregnation is performed.

[0051] It should be noted that, in this invention, the average value and coefficient of variation of the unit area weight of the long fiber nonwoven fabric are values ​​determined through the following steps.

[0052] (i) Excluding the area 5cm from both ends of the long fiber nonwoven fabric, collect 10 test pieces of 1cm×1cm each in the longitudinal and transverse directions, for a total of 100 pieces.

[0053] (ii) Weigh each of the following under standard conditions (g), using the mass per 1m 2 mass (g / m 2 Let (g) represent the value, and calculate the weight per unit area w of each test piece. i It should be noted that i is the number (an integer from 1 to 100) corresponding to each test piece.

[0054] (iii) Calculate the average value (arithmetic mean, g / m²) of the 100 test pieces. 2 ), standard deviation (g / m 2 The coefficient of variation (%) is rounded to the nearest integer. It should be noted that the coefficient of variation (%) for weight per unit area is calculated using the following formula.

[0055] [Coefficient of variation of weight per unit area (%)] = [Standard deviation of weight per unit area (g / m²)] 2 ) / [average weight per unit area (g / m²)] 2 )]×100 (formula).

[0056] The average thickness of the long-fiber nonwoven fabric in this invention is preferably 0.30 mm to 1.20 mm, and the coefficient of variation of the thickness of the long-fiber nonwoven fabric is preferably 2.0% to 8.0%. By satisfying both of these conditions, the long-fiber nonwoven fabric exhibits excellent mechanical strength and softness. When impregnated with resin, the roll diameter during the manufacturing of the long-fiber nonwoven fabric does not become excessive, ensuring sufficient winding length and reducing the need for roll-changing operations.

[0057] First, the average thickness of the long-fiber nonwoven fabric is preferably 0.30 mm to 1.20 mm. For this average thickness range, by setting its lower limit to 0.30 mm or more, more preferably 0.32 mm or more, and even more preferably 0.34 mm or more, sufficient mechanical strength as a long-fiber nonwoven fabric can be obtained. On the other hand, for the aforementioned average thickness range, by setting its upper limit to 1.20 mm or less, more preferably 1.18 mm or less, and even more preferably 1.16 mm or less, the roll diameter during the manufacture of the long-fiber nonwoven fabric will not become excessive, ensuring sufficient winding length and reducing roll-changing operations during resin impregnation processing.

[0058] Furthermore, the coefficient of variation of the thickness of the long-fiber nonwoven fabric of the present invention is preferably 2.0% or more and 8.0% or less. Regarding the range of this coefficient of variation, by setting its lower limit to 2.0% or more, more preferably 2.5% or more, and even more preferably 3.0% or more, local impregnation unevenness can be suppressed when resin impregnation is performed. On the other hand, regarding the range of the coefficient of variation of the thickness, by setting its upper limit to 8.0%, preferably 7.5%, and more preferably 7.0% or less, partial impregnation loss can be suppressed when resin impregnation is performed.

[0059] It should be noted that, in this invention, the average thickness and coefficient of variation of the long fiber nonwoven fabric are values ​​determined through the following steps.

[0060] (i) Excluding the area 5cm from both ends of the long fiber nonwoven fabric, collect 10 test pieces of 1cm×1cm each in the longitudinal and transverse directions, for a total of 100 pieces.

[0061] (ii) The thickness t of each test piece was measured using a thickness gauge (e.g., "Litematic VL-50-B" manufactured by Mitutoyo Co., Ltd.). i It should be noted that i is the number (an integer from 1 to 100) corresponding to each test piece.

[0062] (iii) Calculate the average value (mm), standard deviation (mm), and coefficient of variation (%) of 100 test pieces, rounding each to the third decimal place. It should be noted that the coefficient of variation (%) of the thickness is calculated using the following formula.

[0063] [Coefficient of variation of thickness (%)] = [Standard deviation of thickness (mm)] / [Average thickness (mm)] × 100 (Formula).

[0064] Preferably, the average apparent density of the long-fiber nonwoven fabric of the present invention is 0.05 g / cm³. 3 Above 0.17g / cm 3The coefficient of variation of the apparent density of the long-fiber nonwoven fabric is preferably 10.0% to 20.0%. By satisfying both of these conditions, a long-fiber nonwoven fabric with high mechanical strength and moderate softness is produced, which is also a long-fiber nonwoven fabric with excellent workability during resin impregnation processing.

[0065] First, the average apparent density of the long-fiber nonwoven fabric is preferably 0.05 g / cm³. 3 Above 0.17g / cm 3 The following pertains to the range of the average apparent density, with its lower limit preferably set at 0.05 g / cm³. 3 The above, more preferably 0.06 g / cm³ 3 The above is further preferred to be 0.07 g / cm³. 3 This results in a long-fiber nonwoven fabric with high mechanical strength in sheet form. On the other hand, regarding the range of the average apparent density, its upper limit is preferably 0.17 g / cm³. 3 The following is more preferably 0.16 g / cm³. 3 The following is a further preferred value: 0.15 g / cm³ 3 The following results in a long-fiber nonwoven fabric with moderate softness, which is an excellent long-fiber nonwoven fabric for resin impregnation processing.

[0066] Furthermore, the coefficient of variation of the apparent density of the long-fiber nonwoven fabric of the present invention is preferably 10.0% or more and 20.0% or less. Regarding the range of this coefficient of variation, by setting its lower limit to 10.0% or more, more preferably 10.5% or more, and even more preferably 11.0% or more, local impregnation unevenness can be suppressed when resin impregnation is performed. On the other hand, regarding the range of the coefficient of variation of the apparent density, by setting its upper limit to 20.0%, preferably 19.5%, and more preferably 19.0% or less, local impregnation defects can be suppressed when resin impregnation is performed.

[0067] It should be noted that, in this invention, the average value and coefficient of variation of the apparent density of the long fiber nonwoven fabric refer to the values ​​obtained through the following steps.

[0068] (i) The weight per unit area w of the aforementioned test pieces i (g / m 2 Thickness t i (mm), the apparent density d of each test piece is calculated using the following formula. i (g / cm) 3 ).

[0069] d i =w i / t i / 1,000 (formula) (ii) Calculate the average apparent density d of the 100 test pieces using the following formula. ave (Arithmetic mean, g / cm³) 3 ), standard deviation d sdev (g / cm) 3 ), coefficient of variation d CV (%), average value d ave Standard deviation d sdev Rounding is performed to the third decimal place; coefficient of variation d CV Round the first decimal place.

[0070] d ave =∑d i / 100 (formula) [Mathematical Expression 1] d CV =d sdev / d ave ×100 (formula).

[0071] In the long-fiber nonwoven fabric of the present invention, the transverse stiffness is preferably 40N or more and 500N or less. By making the transverse stiffness of this long-fiber nonwoven fabric preferably 40N or more, more preferably 45N or more, and even more preferably 50N or more, a long-fiber nonwoven fabric with higher mechanical strength is obtained. On the other hand, by making the transverse stiffness of the long-fiber nonwoven fabric preferably 500N or less, more preferably 450N or less, and even more preferably 400N or less, a long-fiber nonwoven fabric with moderate softness is obtained, resulting in excellent workability during resin impregnation processing.

[0072] It should be noted that, in this invention, the transverse stiffness of the long-fiber nonwoven fabric is determined by the "6.7.5 Handle-O-Meter method" of JIS L 1913:2010 "General Nonwoven Fabrics Test Method" and the following steps.

[0073] (i) Collect test pieces with a longitudinal length of 200 mm and a transverse length of 200 mm from three points on the long fiber nonwoven fabric.

[0074] (ii) At a position 67 mm from any side, measure different parts of the back of the watch in both the longitudinal and transverse directions and read the highest value (N).

[0075] (iii) Find the sum of the highest values ​​of the four sides and calculate the average of the three values.

[0076] (iv) The first decimal place of the above arithmetic mean is rounded to the nearest whole number and is taken as the transverse stiffness (N) of the long fiber nonwoven fabric.

[0077] In the long-fiber nonwoven fabric of the present invention, the longitudinal tensile strength is preferably 90 N / 5 cm or more and 1,100 N / 5 cm or less. By making the longitudinal tensile strength of this long-fiber nonwoven fabric preferably 90 N / 5 cm or more, more preferably 95 N / 5 cm or more, and even more preferably 100 N / 5 cm or more, a long-fiber nonwoven fabric with higher mechanical strength is obtained. On the other hand, the longitudinal tensile strength of the long-fiber nonwoven fabric is preferably 1,100 N / 5 cm or less, more preferably 1,050 N / 5 cm or less, and even more preferably 1,000 N / cm or less, a long-fiber nonwoven fabric with moderate softness is obtained, and the workability during resin impregnation processing becomes excellent.

[0078] It should be noted that, in this invention, the longitudinal tensile strength of the long-fiber nonwoven fabric is as described above. According to section 6.3 "Tensile strength and elongation" of JIS L1913:2010 "General long-fiber nonwoven fabric test method", the tensile testing machine used is the Tensilon universal testing machine "RTG-1250" manufactured by A&D Corporation or a testing machine with equivalent performance, and the following values ​​are measured.

[0079] (1) Collect 5 test pieces with a length of 30cm and a width of 5.0cm at equal intervals along the longitudinal direction.

[0080] (2) Apply a load until the sample breaks under the conditions of a clamping interval of 20cm and a tensile speed of 100±10mm / min.

[0081] (3) Set the strength of the sample under maximum load as tensile strength (N / 5cm), calculate the average value of 5 points, and round the first decimal place.

[0082] The applications of the long-fiber nonwoven fabric of this invention are not particularly limited. However, due to its uniform weight per unit area, softness, and excellent mechanical strength, it is particularly suitable for applications requiring mechanical strength, such as civil engineering, agriculture, forestry, and industrial materials. It is also suitable for applications requiring a soft feel, such as footwear, bags, clothing, automotive interior materials, interior decoration, and furniture. Of course, its applications are not limited to these; it can also be used as an abrasive cloth, wiping cloth, etc.

[0083] [Manufacturing method of long fiber nonwoven fabric] The method for manufacturing the long-fiber nonwoven fabric of the present invention will be described in detail.

[0084] The manufacturing method of the long-fiber nonwoven fabric of the present invention yields a long-fiber nonwoven fabric with an average transmittance of 150 to 250 and a coefficient of variation of transmittance of 5.0% to 11.0%. The method for manufacturing the long-fiber nonwoven fabric includes: The process of forming a single-component fiber with polyester resin as the main component involves melting and extruding a thermoplastic resin with polyester resin as the main component from a spinneret, and then using an ejector to draw and stretch the thermoplastic resin. The process of forming a fiber web, wherein the single-component fibers are stacked on a moving collecting surface; The process of forming a temporary welded sheet includes passing the fiber web through a pair of heated rollers; and The process of mechanically interlacing the temporary welded pieces, The spinning speed during traction is between 3,000 m / min and 6,000 m / min. The surface temperature T of the hot roller S (°C) satisfies the following equation 1, The linear pressure of the hot roller is above 90 N / cm and below 1,000 N / cm. The mechanical weaving is achieved through hydroentangling and / or acupuncture. T m -120≤T S ≤T m -50 (Equation 1) Among them, T m (°C) is the melting point of the polyester resin.

[0085] (1) Process of forming single-component fibers with polyester resin as the main component First, in this process, a thermoplastic resin with polyester resin as the main component is melt-extruded from a spinneret. Here, "thermoplastic resin with polyester resin as the main component" refers not only to the aforementioned polyester resin itself, but also to thermoplastic resin containing more than 50% by mass of the aforementioned polyester resin.

[0086] In the aforementioned spinneret, the shape of the ejection orifice, corresponding to the cross-sectional shape of the single-component fiber, can be circular, elliptical, polygonal, multi-lobed, or a combination thereof. Among these, from the viewpoint of efficiently achieving interweaving of the single-component fibers and ensuring their firm interweaving, a circular cross-section is a more preferred method.

[0087] In addition, the temperature T in the spinneret of the aforementioned thermoplastic resin P (°C) Preferably, it satisfies the following formula 2.

[0088] Tm ≤T P ≤T m +70 (Equation 2) Among them, T m (°C) is the melting point of the aforementioned polyester resin.

[0089] Furthermore, the temperature T in the spinneret of the aforementioned thermoplastic resin P (°C) More preferably, it satisfies the following formula 2-1, and even more preferably, it satisfies the following formula 2-2.

[0090] T m +10≤T P ≤T m +60 (Equation 2-1) T m +20≤T P ≤T m +50 (Equation 2-2) Among them, T m (°C) is the melting point of the aforementioned polyester resin. By setting it to the above range, especially by setting it to Formula 2-1 and Formula 2-2, it is easier to cool the filaments ejected from the spinneret, suppress the fusion of fibers with each other, and make it easier to spin stably even fine fiber diameters.

[0091] In addition, the temperature T of the aforementioned spinneret C (°C) Preferably, it satisfies the following formula 3.

[0092] T m ≤T C ≤T m +70 (Equation 3) Among them, T m (°C) is the melting point of the aforementioned polyester resin.

[0093] In addition, the aforementioned thermoplastic resin is drawn and stretched using an ejector. In this way, a single-component fiber with polyester resin as the main component is formed.

[0094] The spinning speed during the aforementioned traction is 3,000 m / min to 6,000 m / min. By setting the spinning speed to 3,000 m / min or more, preferably 3,500 m / min or more, long-fiber nonwoven fabrics with excellent mechanical strength can be obtained. On the other hand, by setting the spinning speed to 6,000 m / min or less, preferably 5,500 m / min or less, long-fiber nonwoven fabrics with higher uniformity and less unevenness can be obtained.

[0095] (2) Process of forming fiber web Next, in this process, the aforementioned single-component fibers are deposited on a moving collecting surface, thereby forming a fiber web. "Deposited on a moving collecting surface" means, for example, deposited on a rotating mesh conveyor belt, where the belt portion is a perforated plate, a mesh, or a porous material. To prevent the deposited single-component fibers from falling into the mesh conveyor belt or clogging the perforated plate or porous material (hereinafter referred to as "perforated portions, etc."), the size of the perforated portions is preferably appropriately set considering the thermoplastic resin constituting the single-component fibers and the fiber diameter of the single-component fibers. It should be noted that the belt portion can be made of metal or synthetic resin. Furthermore, it is preferable to provide a fiber-opening plate at a certain distance above the moving collecting surface where the aforementioned single-component fibers are deposited, thereby restricting the fiber arrangement and allowing it to deposit.

[0096] (3) The process of forming temporary welded pieces In addition, during this process, the aforementioned fiber web is passed through a pair of hot rollers. This forms a temporary welded sheet.

[0097] At this time, the surface temperature T of the aforementioned hot roller S (°C) satisfies the following equation 1.

[0098] T m -120≤T S ≤T m -50 (Equation 1) Among them, T m (°C) is the melting point of the aforementioned polyester resin. Furthermore, the surface temperature T of the aforementioned hot roller... S (°C) More preferably, it satisfies Equation 1-1 below, and even more preferably, it satisfies Equation 1-2.

[0099] T m -110≤T S ≤T m -60 (Equation 1-1) T m -100≤T S ≤T m -70 (Equation 1-2) Among them, T m (°C) is the melting point of the aforementioned polyester resin. This is achieved by raising the surface temperature T of the aforementioned hot roller. S When the temperature (°C) is within the above range, fiber crystallization can be minimized, and a long-fiber nonwoven fabric with higher interweaving properties can be obtained in the mechanical weaving process described later. In particular, by setting T within the above range... SHigher temperatures can further enhance the strength of temporary welded sheets, resulting in long-fiber nonwoven fabrics with excellent process passability. This is achieved by increasing the temperature (T) within the aforementioned range. S To achieve a lower temperature, during the mechanical weaving process described later, fiber breakage can be reduced, weaving properties can be improved, and a long-fiber nonwoven fabric with excellent hand feel can be obtained.

[0100] Furthermore, the linear pressure of the aforementioned hot roller is 90 N / cm or more and 1,000 N / cm or less. By setting this linear pressure to 90 N / cm or more, preferably 100 N / cm or more, a long-fiber nonwoven fabric with sufficient mechanical strength for conveying can be obtained. On the other hand, by setting the linear pressure to 1,000 N / cm or less, preferably 990 N / cm or less, excessive welding can be prevented, and fiber breakage can be further reduced and interlacing properties improved during the mechanical weaving process described later, resulting in a long-fiber nonwoven fabric with excellent hand feel.

[0101] As the aforementioned heated roller, a flat roller is particularly preferred. From the perspective of improving the strength of long-fiber nonwoven fabric, it is most preferable to use a pair of heated flat rollers for temporary welding.

[0102] In this invention, a "flat roller" refers to a metal roller or elastic roller whose surface has no unevenness. Furthermore, a pair of flat rollers refers to a pair of metal rollers or a pair of metal rollers and elastic rollers. An elastic roller is a roller formed from a material that is more elastic than a metal roller. Examples of elastic rollers include paper rollers (made of paper, cotton, aramid paper, etc.) and resin rollers formed from urethane resins, epoxy resins, silicone resins, polyester resins, and hard rubber, or mixtures thereof.

[0103] (4) Implementing mechanically interwoven processes Furthermore, in this process, the aforementioned temporary welded sheets are mechanically interlaced. This mechanical interlacing can be achieved through hydroentangling and / or needle punching. Specifically, examples include: performing hydroentangling only once; performing hydroentangling only multiple times; or performing needle punching only once; performing needle punching only multiple times; furthermore, performing hydroentangling and needle punching at least once each; etc. Among these, needle punching is preferred from the perspective of not using large amounts of water resources and achieving high uniformity of interlacing; specifically, performing needle punching only once or performing needle punching only multiple times is preferred.

[0104] The conditions for acupuncture vary depending on the shape and type of needles used. For example, it is preferable to set the needle depth to 5mm to 20mm and the needle density to 90 needles / cm². 2 ~310 roots / cm 2 The temporary weld patch is perforated on one side or both sides of the front and back, with a preferred needle density of 100 needles / cm. 2 ~300 strands / cm2 It should be noted that the needle depth mentioned here refers to the distance from the surface of the base plate during needle punching to the tip of the needle that is further inserted.

[0105] (5) Post-processing steps The long fiber nonwoven fabric of the present invention can be obtained through the above-mentioned processes and can be directly used for various purposes. In addition, depending on its use and purpose, various treatment agents such as opening and hydrophilic treatment can be applied, as well as layering with other materials, printing, resin processing, etc.

[0106] For example, hole-making can involve creating a through hole (through hole) that extends along the thickness direction, or it can involve creating a non-through hole that extends to the middle of the hole.

[0107] Furthermore, regarding the application of the treatment agent, a rolling and drying process can be incorporated as needed. There are no particular limitations on the method for adhering the treatment agent to the long-fiber nonwoven fabric; examples include coating with a liquid containing a dissolved or dispersed treatment agent, and impregnation. In addition to hydrophilic agents, examples of treatment agents include antibacterial agents, antioxidants, preservatives, matting agents, pigments, rust inhibitors, fragrances, and defoamers.

[0108] In addition, known methods of printing include gravure printing, stencil printing, screen printing, and offset printing.

[0109] In addition, regarding resin processing, resins such as polyurethane can also be impregnated or coated using known methods.

[0110] Example Next, the present invention will be described in detail based on embodiments. However, the present invention is not limited to these embodiments.

[0111] [Determination Method] The evaluation methods and measurement conditions used in the examples are described below. It should be noted that, unless otherwise specified, the measurements of each physical property are performed based on the aforementioned methods.

[0112] (1) Melting point of polyester (°C) The differential scanning calorimeter was used to perform the measurements using the "DSC-2 type" manufactured by Perkin Elmer Japan Co., Ltd.

[0113] (2) Intrinsic viscosity (IV) of polyester The intrinsic viscosity (IV) of polyester is determined and calculated using the following methods.

[0114] (i) Dissolve 8g of sample in 100mL of o-chlorophenol.

[0115] (ii) After placing the solution in an atmosphere at 25°C, calculate the relative viscosity using an Orstätten viscometer using the following formula. or r .

[0116] or r = or / or 0 = (t × d) / (t0 × d0) (in, or Indicates the viscosity of the polymer solution. or 0 represents the viscosity of o-chlorophenol, t represents the drop time of the solution (seconds), and d represents the density of the solution (g / cm³). 3 ), t0 represents the falling time of o-chlorophenol (seconds), and d0 represents the density of o-chlorophenol (g / cm³). 3 ). (iii) Next, based on relative viscosity or r The intrinsic viscosity (IV) is calculated using the following formula.

[0117] Intrinsic viscosity (IV) = 0.0242 or r +0.2634.

[0118] (3) Average single fiber diameter (μm) of single component fiber The average single fiber diameter of the single component fiber of the present invention was calculated using the above method with a scanning electron microscope "VHX-D510" manufactured by KEYENCE Co., Ltd.

[0119] (4) Average light transmittance of long-fiber nonwoven fabric (g / m²) 2 ) The average transmittance of long-fiber nonwoven fabric was measured and calculated using the aforementioned method.

[0120] (5) Coefficient of variation of light transmittance of long fiber nonwoven fabric (%) The coefficient of variation of the transmittance of long-fiber nonwoven fabric was determined and calculated using the aforementioned method.

[0121] (6) Average weight per unit area of ​​long fiber nonwoven fabric (g / m²) 2 ) The average weight per unit area of ​​long-fiber nonwoven fabric was determined and calculated using the aforementioned method.

[0122] (7) Coefficient of variation of unit area weight of long fiber nonwoven fabric (%) The coefficient of variation of the unit area weight of long fiber nonwoven fabric was determined and calculated using the aforementioned method.

[0123] (8) Average thickness of long fiber nonwoven fabric (mm) The average thickness of the long-fiber nonwoven fabric was determined and calculated using the aforementioned method.

[0124] (9) Coefficient of variation of the thickness of long fiber nonwoven fabric (%) The coefficient of variation of the thickness of the long-fiber nonwoven fabric was determined and calculated using the aforementioned method.

[0125] (10) Average apparent density of long fiber nonwoven fabric (g / cm³) 3 ) The average apparent density of the long-fiber nonwoven fabric was determined and calculated using the aforementioned method.

[0126] (11) Coefficient of variation of apparent density of long fiber nonwoven fabric (%) The coefficient of variation of the apparent density of long-fiber nonwoven fabric was determined and calculated using the aforementioned method.

[0127] (12) Transverse stiffness (N) of long fiber nonwoven fabric The transverse stiffness of long-fiber nonwoven fabric is used as an indicator of its softness and is measured and calculated using the methods described above.

[0128] (13) Longitudinal tensile strength of long fiber nonwoven fabric (N / 5cm) The longitudinal tensile strength of the long-fiber nonwoven fabric was measured and calculated using the aforementioned method using a Tensilon universal testing machine "RTG-1250" manufactured by A&D Corporation as the tensile testing machine, and as an indicator of the mechanical strength of the long-fiber nonwoven fabric.

[0129] (14) Ease of post-processing of long fiber nonwoven fabrics As for the ease of post-processing of long-fiber nonwoven fabrics, resin processing was performed on the long-fiber nonwoven fabrics obtained in the Examples and Comparative Examples under the following conditions: a surfactant was impregnated into the long-fiber nonwoven fabric, and then resin was applied at 80 g / m². 2 The polyurethane resin is coated with a specific amount. Then, it is impregnated with a coagulating solution obtained from a mixture of water and dimethylformamide and dried at 140°C. It should be noted that the evaluation is conducted in five stages by 20 judges who have been engaged in the manufacture or development of long-fiber nonwoven fabrics for more than three years. The evaluation with the most ratings from the 20 judges is taken as the evaluation of the long-fiber nonwoven fabric. It should be noted that if there are multiple most rated ratings, the middle rating is taken. For example, if A and C are the most rated, B is taken; if B, C, and D are the most rated, C is taken. Furthermore, if there is no rating in the exact middle, the evaluation is conducted in an upward orientation manner. For example, if A and B are the most rated, A is taken; if A, B, and D are the most rated, B is taken.

[0130] A: The resin-rich areas and the areas where there is no resin at all are both absent, resulting in a uniform state with no resin unevenness.

[0131] B: Between A and C C: The presence of either resin-rich portions or completely resin-free portions indicates a certain degree of resin heterogeneity.

[0132] D: Between C and E E: This indicates a state of resin heterogeneity, where both resin-rich and resin-free portions exist equally.

[0133] [Polyester-based resin used] Next, details of the polyester resins used in the Examples and Comparative Examples will be described.

[0134] • Dried to a moisture content of less than 50 ppm by mass, with an intrinsic viscosity (IV) of 0.65 and a melting point T m Polyethylene terephthalate (hereinafter, including those referred to as "PET" in the table) is heated to 260°C. • Dried to a moisture content of less than 50 ppm by mass, with an intrinsic viscosity (IV) of 0.64, an isophthalic acid copolymerization rate of 11 mol%, and a melting point T m It is a copolymer of polyethylene terephthalate (hereinafter, including those denoted as "co-PET" in the table) at 230℃.

[0135] [Example 1] (The process of forming a single-component fiber with polyester resin as the main component) The aforementioned PET is melted at a temperature of 295°C. Then, it is spun out through the circular extrusion orifice of a spinneret at a spinneret temperature of 295°C. In addition, the spun polyester resin is drawn, sucked and stretched using an ejector at a spinning speed of 4,500 m / min to form a single-component fiber with polyester resin as the main component.

[0136] (The process of forming a fiber web) The obtained single-component fibers are stacked on a moving collecting surface to form a fiber web. At this point, the fiber arrangement is restricted by spraying the aforementioned single-component fibers from the fiber opener, and the moving collecting surface achieves a nonwoven fabric with a unit area weight of 115 g / m². 2 The moving mesh conveyor belt had its speed adjusted in this manner. Furthermore, the average single fiber diameter of the resulting fiber web was 12.4 μm.

[0137] (The process of forming a temporary welded piece) For the obtained nonwoven web, a pair of heated flat rollers are used as a pair of hot rollers, and the air is fed into these hot rollers to form a temporary welded sheet. At this time, the surface temperature of the hot rollers is maintained at 170℃ (T). m -90℃), so that the linear pressure of the hot roller is 589 N / cm.

[0138] (The process involves mechanical interweaving) The obtained temporary welded sheet is mechanically interlaced. Specifically, the needle depth is 5 mm and the needle count is 61 needles / cm on both the front and back sides. 2 Needle punching was performed under the specified conditions. The physical properties of the resulting nonwoven fabric are shown in Table 1.

[0139] [Example 2] In the process of mechanical interlacing, except for the number of hands being 122 per cm on each side of the watch back. 2 Except for needle punching under the same conditions, long-fiber nonwoven fabrics were obtained using the same method as in Example 1. The evaluation results of the obtained nonwoven fabrics are shown in Table 1.

[0140] [Example 3] In the process of forming the fiber web, the weight per unit area of ​​the resulting nonwoven fabric will be 115 g / m². 2 The method of adjusting the moving speed of the mesh conveyor belt was changed to 160g / m. 2 The moving speed of the mesh conveyor belt was adjusted in the same way as in Example 1, and long-fiber nonwoven fabric was obtained under the same conditions. The physical properties of the obtained nonwoven fabric are shown in Table 1.

[0141] [Example 4] In the process of forming the fiber web, the weight per unit area of ​​the resulting nonwoven fabric will be 115 g / m². 2 The method of adjusting the moving speed of the mesh conveyor belt is changed to 50g / m. 2 The moving speed of the mesh conveyor belt was adjusted in the same way as in Example 1, and long-fiber nonwoven fabric was obtained under the same conditions. The physical properties of the obtained nonwoven fabric are shown in Table 1.

[0142] [Table 1] [Comparative Example 1] In the process of forming the fiber web, the weight per unit area of ​​the resulting nonwoven fabric will be 115 g / m². 2 The method of adjusting the moving speed of the mesh conveyor belt was changed to 210g / m. 2 The moving speed of the mesh conveyor belt was adjusted in the same way as in Example 1, and long-fiber nonwoven fabric was obtained under the same conditions. The physical properties of the obtained nonwoven fabric are shown in Table 2.

[0143] [Comparative Example 2] In the process of forming the fiber web, the weight per unit area of ​​the resulting nonwoven fabric will be 115 g / m². 2 The method of adjusting the moving speed of the mesh conveyor belt was changed to 35g / m. 2 The moving speed of the mesh conveyor belt was adjusted in the same way as in Example 1, and long-fiber nonwoven fabric was obtained under the same conditions. The physical properties of the obtained nonwoven fabric are shown in Table 2.

[0144] [Comparative Example 3] In the process of mechanical interlacing, besides the needle depth being 15mm and the needle count being 233 needles / cm on both the front and back, 2 Except for needle punching under the same conditions as in Example 1, long-fiber nonwoven fabrics were obtained using the same method. The evaluation results of the obtained nonwoven fabrics are shown in Table 2.

[0145] [Comparative Example 4] In the (mechanical interlacing process), except for the number of hands being 35 per cm on each side of the watch back. 2 Except for needle punching under the same conditions as in Example 1, long-fiber nonwoven fabrics were obtained using the same method. The evaluation results of the obtained nonwoven fabrics are shown in Table 2.

[0146] [Table 2] [Comparative Example 5] In the process of forming the fiber web, no fiber opener is used for spraying, and the fiber web is captured and formed. Otherwise, long-fiber nonwoven fabric is obtained under the same conditions as in Example 1. The evaluation results of the obtained nonwoven fabric are shown in Table 3.

[0147] [Comparative Example 6] In the process of forming the fiber web, the single-hole ejection amount is adjusted so that the average single fiber diameter of 12.4 μm becomes 25.4 μm fiber without the use of a fiber-opening plate, and the fiber web is captured and formed. Otherwise, a long fiber nonwoven fabric is obtained under the same conditions as in Example 1.

[0148] Furthermore, in the (mechanical weaving process), except for needle punching at a needle depth of 15 mm, long-fiber nonwoven fabric was obtained using the same method as in Example 1. The evaluation results of the obtained nonwoven fabric are shown in Table 3.

[0149] [Comparative Example 7] In the process of forming a single-component fiber mainly composed of polyester resin, the aforementioned PET and CO-PET were melted at temperatures of 295°C and 280°C, respectively. Using PET as the core component and CO-PET as the sheath component, the fiber was spun from the nozzle of a circular spinneret at a spinneret temperature of 295°C with a core-to-sheath mass ratio of 80:20 to obtain a core-sheath type composite fiber (referred to as "PET / CO-PET" in Table 3). This core-sheath type composite fiber is not a single-component fiber, but for convenience, the spinning speed, average single fiber diameter, and presence or absence of a fiber opener are listed in the single-component fiber section of Table 3. Furthermore, in the process of forming a fiber web, except that the surface temperature of the hot roller was changed to 130°C, a long-fiber nonwoven fabric was obtained under the same conditions as in Example 1. The physical properties of the obtained nonwoven fabric are shown in Table 3.

[0150] [Table 3] The properties of the obtained long-fiber nonwoven fabrics are shown in Tables 1, 2, and 3. The unit area weight of the long-fiber nonwoven fabrics in Examples 1 to 4 is 40 g / m². 2 Above 170g / m 2 The average transmittance is between 150 and 250, and the coefficient of variation of transmittance is between 5.0% and 11.0%. Therefore, nonwoven fabrics with excellent softness and mechanical strength can be obtained, which are suitable for post-processing such as resin processing.

[0151] On the other hand, the long-fiber nonwoven fabric of Comparative Example 1 has a large coefficient of variation in unit area weight, high transverse stiffness, and poor softness. The long-fiber nonwoven fabric of Comparative Example 2 has excessively low transverse stiffness, resulting in poor mechanical strength. The long-fiber nonwoven fabrics of Comparative Examples 3-5 have low average light transmittance and poor post-processing properties. Furthermore, the long-fiber nonwoven fabric of Comparative Example 6 has large coefficients of variation in thickness and apparent density, high transverse stiffness, and poor softness. The long-fiber nonwoven fabric of Comparative Example 7 has high transverse stiffness and poor softness.

[0152] Industrial availability The long-fiber nonwoven fabric of this invention is particularly suitable for applications requiring mechanical strength, such as civil engineering, agriculture, forestry, and industrial materials, as well as applications requiring a soft feel, such as footwear, bags, clothing, automotive interior materials, interior decoration, and furniture. It is also suitable for applications such as abrasive cloths and wiping cloths.

Claims

1. Long-fiber nonwoven fabric, which is a long-fiber nonwoven fabric composed of single-component fibers with polyester resin as the main component, wherein, The average weight per unit area of ​​the long-fiber nonwoven fabric is 40 g / m². 2 The above 170g / m 2 The average transmittance of the long-fiber nonwoven fabric is between 150 and 250, and the coefficient of variation of the transmittance of the long-fiber nonwoven fabric is between 5.0% and 11.0%.

2. The long-fiber nonwoven fabric as described in claim 1, wherein, The average single fiber diameter of the single component fiber is above 8.0 μm and below 20.0 μm.

3. The long-fiber nonwoven fabric as described in claim 1 or 2, wherein, The coefficient of variation of the unit area weight of the long fiber nonwoven fabric is above 10% and below 20%.

4. The long-fiber nonwoven fabric as described in claim 1 or 2, wherein, The average thickness of the long-fiber nonwoven fabric is between 0.30 mm and 1.20 mm, and the coefficient of variation of the thickness of the long-fiber nonwoven fabric is between 2.0% and 8.0%.

5. The long-fiber nonwoven fabric as described in claim 1 or 2, wherein, The average apparent density of the long-fiber nonwoven fabric is 0.05 g / cm³. 3 Above 0.17g / cm 3 The coefficient of variation for apparent density is between 10.0% and 20.0%.

6. The long-fiber nonwoven fabric as described in claim 1 or 2, wherein, The transverse stiffness of the long-fiber nonwoven fabric is above 40N and below 500N.

7. A method for manufacturing long-fiber nonwoven fabric, wherein the manufacturing method yields a long-fiber nonwoven fabric with an average transmittance of 150 to 250 and a coefficient of variation of transmittance of 5.0% to 11.0%. The method for manufacturing the long-fiber nonwoven fabric includes: The process of forming single-component fibers with polyester resin as the main component, wherein, Thermoplastic resin, mainly composed of polyester resin, is melted and extruded from a spinneret, and then pulled and stretched using an ejector. The process of forming a fiber web, wherein the single-component fibers are stacked on a moving collecting surface; The process of forming a temporary welded sheet includes passing the fiber web through a pair of heated rollers; and The process of mechanically interlacing the temporary welded pieces, The spinning speed during traction is between 3,000 m / min and 6,000 m / min. The surface temperature T of the hot roller S (°C) satisfies the following equation 1, The linear pressure of the hot roller is above 90 N / cm and below 1,000 N / cm. The mechanical weaving is achieved through hydroentangling and / or acupuncture. T m -120≤T S ≤T m -50 (Equation 1) Among them, T m (°C) is the melting point of the polyester resin.

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