Nonwoven fabric, production method thereof, moisture regulator, and laminate

Abstract

To provide a nonwoven fabric applicable to moisture regulator of polyester made by copolymerizing polyethylene glycol, achieving excellent moisture absorption and desorption, having both of self moisture controllability and dimension stability, through density control of the nonwoven fabric.SOLUTION: The nonwoven fabric includes fiber that contains polyester. The polyester is a copolymerized polyester containing copolymerized polyethylene glycol having a number average molecular weight of 1000 or more and 35000 or less in an amount of 5 mass% or more and 70 mass% or less. The nonwoven fabric has a density of 0.01 g / cm3 or more and less than 0.15 g / cm3.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a nonwoven fabric that combines self-sustaining moisture control properties with dimensional stability. [Background technology]

[0002] In recent years, homes have become more airtight and insulated to reduce energy consumption and provide a comfortable living environment. For example, moisture-proof sheets, airtight tape, and insulation materials are used inside walls and under floors to achieve high airtightness. In addition, insulation materials are used on exterior walls, under floors, and in the attic to achieve high insulation.

[0003] Highly airtight and highly insulated homes minimize the flow of air in and out of the outdoors, which poses a challenge for them: internal condensation within building materials such as walls. Internal condensation can be suppressed by using porous materials such as diatomaceous earth and silica gel, which are moisture-absorbing and desorbing materials. However, excessive moisture absorption can lead to an "overly dry" state, with low humidity levels in the living space. For this reason, it is important for moisture-absorbing and desorbing materials to not only have moisture-absorbing properties, but also to have the ability to independently regulate humidity levels in the living space, independently maintaining the appropriate humidity level.

[0004] Furthermore, since moisture-absorbing and desorbing materials are used in limited spaces such as inside walls, it is important to suppress changes in apparent dimensions when absorbing and releasing moisture. However, if the moisture absorption amount is too high, the material will swell too much when absorbing moisture, and the insulation material near the material will also absorb moisture, causing internal condensation. In other words, it is important for moisture-absorbing and desorbing materials to have a good balance between self-sustaining moisture control and dimensional stability.

[0005] To date, natural wood, diatomaceous earth plaster walls, panel-shaped wall materials, and various nonwoven fabrics have been proposed as moisture-absorbing and desorbing materials, and among these, nonwoven fabrics have attracted attention as a material that is highly flexible and can be applied to a variety of shapes. For example, Patent Document 1 proposes an absorbent nonwoven fabric that is made of absorbent fibers containing a thermoplastic absorbent resin copolymerized with polyalkylene glycol. It is described that this nonwoven fabric has high absorbency and water retention without significantly compromising strength, making it suitable for use in applications requiring water absorption and moisture absorption / desorption.

[0006] Furthermore, Patent Document 2 proposes a moisture-absorbing fiber structure that is a nonwoven fabric having a specific density and basis weight, in which water-absorbing and moisture-absorbing fibers and organic chemical fibers are bonded together with a thermal adhesive. It is described that this provides a moisture-absorbing fiber structure that is excellent in both moisture absorption amount and moisture absorption rate and has washing durability.

[0007] Patent Document 3 proposes a building material that is made of two or more types of fibers, at least one of which is a thermally adhesive fiber. It describes that the material has high porosity and high rigidity, is lightweight and easy to work with, and also has high humidity control properties due to the use of moisture absorbing and releasing fibers. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-299424 [Patent Document 2] Japanese Patent Publication No. 2020-76176 [Patent Document 3] Japanese Patent Application Laid-Open No. 2009-97207 Summary of the Invention [Problem to be solved by the invention]

[0009] The technology described in Patent Document 1 is a nonwoven fabric composed of water-absorbent fibers containing a water-absorbent thermoplastic resin copolymerized with polyalkylene glycol, and if the water-absorbent fiber content is at a specific level, it can have excellent water absorption and water retention properties.However, even so, such water-absorbent thermoplastic resins have a structure that makes it easy for moisture to be trapped inside the resin and difficult for moisture to be released, so they have the problem of being poor in terms of self-sustaining moisture control and dimensional stability.

[0010] The technology described in Patent Document 2 is a nonwoven fabric in which cross-linked acrylate fibers and polyester fibers are fixed together as moisture absorbing and releasing fibers with a thermal adhesive, while the technology described in Patent Document 3 is a mixed fiber nonwoven fabric in which cross-linked acrylate fibers are used as moisture absorbing and releasing fibers, core-sheath polyester fibers are used as thermally adhesive fibers, and polyester fibers are used as reinforcing fibers. Both Patent Documents 2 and 3 are mixed fiber nonwoven fabrics with polyester fibers, and while the high polyester fiber content provides a certain degree of dimensional stability, the cross-linked acrylate fibers have low moisture releasing properties, resulting in an issue of poor self-standing moisture control.

[0011] Therefore, an object of the present invention is to provide a nonwoven fabric that is excellent in moisture absorption and release and that can simultaneously achieve self-sustaining moisture control properties and dimensional stability. [Means for solving the problem]

[0012] Means for Solving the Problems The present inventors have conducted extensive research in order to achieve the above-mentioned object, and as a result have discovered that a nonwoven fabric composed of fibers containing a polyester in which the number average molecular weight of polyethylene glycol and the copolymerization amount thereof are within a specific range, and in which the density is within a specific range, can provide a nonwoven fabric that is excellent in moisture absorption and release properties and can achieve both self-sustaining moisture control properties and dimensional stability.

[0013] The present invention aims to solve the above problems, and provides the following inventions.

[0014] [1] A nonwoven fabric made of fibers containing polyester, wherein the polyester is a copolymerized polyester obtained by copolymerizing 5% by mass or more and 70% by mass or less of polyethylene glycol having a number average molecular weight of 1,000 to 35,000, and the density of the nonwoven fabric is 0.01 g / cm 3 More than 0.15g / cm 3 Less than 100% nonwoven fabric.

[0015] [2] The nonwoven fabric according to [1], wherein the copolymerized polyester has a polyester structure consisting of repeating units of an esterification reaction product of an aromatic dicarboxylic acid and an alkylene glycol, and the alkylene glycol is 1,4-butanediol.

[0016] [3] The nonwoven fabric according to [1] or [2], wherein the change in fiber diameter of the fibers in a wet state is 1.01 times or more and 2.50 times or less.

[0017] [4] The nonwoven fabric according to any one of [1] to [3] above, wherein the nonwoven fabric is three-dimensionally entangled.

[0018] [5] The nonwoven fabric according to any one of [1] to [4], wherein the nonwoven fabric contains one or more compounds selected from the group consisting of alkali metal halides, alkaline earth metal halides, ammonium halides, and betaine, and the content of the compounds is 0.1% by mass or more and 5.0% by mass or less.

[0019] [6] The nonwoven fabric according to any one of [1] to [5], which satisfies the following formula 1: (MR2-MR1)×m≧10 (Formula 1) Here, MR2 is the moisture absorption rate of the nonwoven fabric when the ambient temperature is 30°C and the humidity is 90%RH, MR1 is the moisture absorption rate of the nonwoven fabric when the ambient temperature is 20°C and the humidity is 65%RH, and m is the basis weight of the nonwoven fabric (g / m 2 )

[0020] [7] The nonwoven fabric according to any one of [1] to [6], wherein the nonwoven fabric is a long-fiber nonwoven fabric.

[0021] [8] A humidity conditioner comprising the nonwoven fabric according to any one of [1] to [7] above.

[0022] [9] A laminate comprising the humidity-conditioning material according to [8] above and a heat insulating material.

[0023]

[10] A method for producing a fiber web, comprising the steps of: melt-spinning a copolymer polyester obtained by copolymerizing 5% by mass or more and 70% by mass or less of polyethylene glycol having a number average molecular weight of 1,000 to 35,000 from a spinneret; and depositing the fibers on a moving collecting surface to form a fiber web, the method comprising the steps of: 3 More than 0.15g / cm 3 The method for producing a nonwoven fabric according to any one of the above [1] to [7], wherein a nonwoven fabric having a thickness of less than 1 / 2 mm is formed.

[0024]

[11] The method for producing a nonwoven fabric according to

[10] , wherein the step of forming the fibers is a spunbonding method or a meltblowing method.

[0025]

[12] A method for producing a nonwoven fabric according to

[10] or

[11] , comprising a step of three-dimensionally entangling the formed fiber web. [Effects of the Invention]

[0026] According to the present invention, by using polyester copolymerized with polyethylene glycol and controlling the density of the nonwoven fabric, it is possible to provide a nonwoven fabric that has excellent moisture absorption and release properties and is capable of achieving both self-sustaining moisture control properties and dimensional stability. DETAILED DESCRIPTION OF THE INVENTION

[0027] [polyester] The nonwoven fabric of the present invention is a nonwoven fabric made of fibers containing polyester.

[0028] The polyester is a copolymerized polyester obtained by copolymerizing 5% by mass or more and 70% by mass or less of polyethylene glycol having a number average molecular weight of 1000 to 35000. More specifically, the polyester is obtained by copolymerizing polyethylene glycol and / or an ester-forming derivative thereof, which will be described later, during the polycondensation reaction of dicarboxylic acid and / or an ester-forming derivative thereof with alkylene glycol.

[0029] As the dicarboxylic acid and / or its ester-forming derivative, it is preferable to use aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and phthalic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexanecarboxylic acid, etc. Among them, terephthalic acid is more preferable because it provides excellent spinning stability during nonwoven fabric production and allows the production of nonwoven fabrics with higher strength.

[0030] The alkylene glycol is preferably selected from 1,4-butanediol, 1,3-propanediol, ethylene glycol, or a combination thereof. Among them, 1,4-butanediol is more preferred because it has high crystallinity, excellent spinning stability during nonwoven fabric production, and can produce nonwoven fabrics with higher moldability and strength.

[0031] The number-average molecular weight of the polyethylene glycol, which is a copolymerization component in the present invention, is 1000 or more, preferably 3000 or more, more preferably 4000 or more, and even more preferably 7000 or more, thereby providing a nonwoven fabric with higher moisture absorption and release properties and better self-sustaining moisture control, as described below. On the other hand, by setting the upper limit of the number-average molecular weight of the polyethylene glycol to 35000 or less, preferably 20000 or less, thread breakage due to thickness variations during spinning can be suppressed, resulting in a nonwoven fabric with higher strength.

[0032] The number average molecular weight of the polyethylene glycol can be measured and calculated using gel permeation chromatography (GPC), specifically as follows. (1) A 12 mg measurement sample is taken from the nonwoven fabric and placed in a sealable vial, to which 1 mL of 28% by mass ammonia water is added, and the sample is heated at 120°C for 5 hours to dissolve the sample. (2) After cooling, add 1.5 mL of 6 mol / L hydrochloric acid and adjust the volume to 5 mL with purified water. After centrifugation, filter through a 0.45 μm filter to obtain the filtrate. (3) The filtrate is subjected to GPC measurement using a measuring device such as a differential refractive index detector "RID-20A" manufactured by Shimadzu Corporation. (4) The number average molecular weight of the polyethylene glycol in the nonwoven fabric is calculated using a molecular weight calibration curve prepared using standard samples of known molecular weight.

[0033] The copolymerization rate of polyethylene glycol, a copolymerization component in the present invention, is 5% by mass or more and 70% by mass or less relative to the copolymerized polyester. A copolymerization rate of 5% by mass or more, preferably 10% by mass or more, more preferably 25% by mass or more, and even more preferably 45% by mass or more, results in a nonwoven fabric with higher moisture absorption and release properties and excellent self-sustaining humidity control, as described below. On the other hand, by setting the upper limit of the copolymerization rate to 70% by mass or less, preferably 60% by mass or less, and more preferably 55% by mass or less, it is possible to suppress thread breakage due to thickness changes during spinning, thereby resulting in a nonwoven fabric with higher strength. Furthermore, it is possible to suppress expansion of the thermoplastic fibers that make up the nonwoven fabric, thereby resulting in a nonwoven fabric with higher dimensional stability.

[0034] The copolymerization rate of polyethylene glycol in the nonwoven fabric can be measured and calculated using a nuclear magnetic resonance (NMR) spectrometer. Specifically, it is as follows. (1) 50 mg of a measurement sample is collected from the nonwoven fabric and dissolved in 1 mL of deuterated hexafluoroisopropanol (HFIP). (2) As a measuring device, for example, "AL-400" manufactured by JEOL Ltd. is used, and the measuring conditions are as follows: 1 NMR measurement is performed using 128 H-NMR scans. (3) The copolymerization rate (mass%) of polyethylene glycol in the nonwoven fabric is calculated from the integral value of the CH2 peak in polyethylene glycol obtained by NMR measurement and the integral value of (H) of the benzene ring in the polyester polymer.

[0035] [Polyester fiber] The fibers constituting the nonwoven fabric of the present invention contain the polyester. The fibers may be fibers made of a single component, composite fibers made of multiple components, or so-called mixed fibers made of a mixture of multiple types of fibers.

[0036] As the composite fiber, a composite fiber in which a high melting point polymer such as polyethylene terephthalate is used as a core component or island component, and a copolymer polyester copolymerized with the above polyethylene glycol is arranged as a sheath component or sea component is preferred.

[0037] When the fibers constituting the nonwoven fabric are core-sheath composite fibers, the copolymerization rate of polyethylene glycol in the sheath component can be measured and calculated using a nuclear magnetic resonance (NMR) spectrometer. Specifically, it is as follows. (1) 50 mg of a measurement sample is collected from the nonwoven fabric and dissolved in 1 mL of deuterated hexafluoroisopropanol (HFIP). (2) As a measuring device, for example, "AL-400" manufactured by JEOL Ltd. is used, and the measuring conditions are as follows: 1 NMR measurement is performed using 128 H-NMR scans. (3) The copolymerization rate (mass%) of polyethylene glycol in the nonwoven fabric is calculated from the integral value of the CH2 peak in polyethylene glycol obtained by NMR measurement and the integral value of (H) of the benzene ring in the polyester polymer. (4) A measurement sample is again taken from the nonwoven fabric and treated with alkali to dissolve the sheath component, leaving only the core component in the yarn. (5) Dissolve 50 mg of the sample obtained in (4) in 1 mL of deuterated hexafluoroisopropanol (HFIP). (6) The solution of (5) is placed and the NMR measurement of (2) is carried out, and the copolymerization rate (mass%) of polyethylene glycol in the core component is calculated from the integral value of the CH2 peak in the polyethylene glycol and the integral value of (H) of the benzene ring in the polyester polymer. (7) The copolymerization rate (mass%) of polyethylene glycol in the core component is subtracted from the copolymerization rate (mass%) of polyethylene glycol in the nonwoven fabric, and the result is divided by the sheath mass ratio. The sheath mass ratio is calculated by observing the cross section of the nonwoven fabric yarn, as described below.

[0038] By using composite fibers, the nonwoven fabric has higher strength and dimensional stability.

[0039] Although the strength of the nonwoven fabric is good even when it is a mixed fiber type that mixes fibers made only of high-melting point polymers with fibers made only of copolymer polyester copolymerized with polyethylene glycol, the specific surface area of ​​the copolymer polyester is larger in the composite fiber, and it has good moisture absorption and release properties when used as a humidity conditioner.

[0040] The composite form of the composite fiber can be, for example, a sheath-core type such as a concentric sheath-core type or an eccentric sheath-core type, or an islands-in-sea type, because it can improve the specific surface area of ​​the copolymer polyester. The cross-sectional shape of the fiber can be, for example, a circular cross section, a flat cross section, a polygonal cross section, a multilobal cross section, a hollow cross section, or the like. A concentric sheath-core type composite form and a circular or flat cross-sectional fiber shape are preferred, because they result in a nonwoven fabric with higher strength and excellent moisture absorption and release properties.

[0041] In core-sheath composite fibers, the core component is a high-melting-point polymer and the sheath component is a low-melting-point polymer, and the melting point difference between them is preferably 15°C or more and 45°C or less. That is, the melting point of the sheath component is preferably [(melting point of core component) - 45]°C or more and [(melting point of core component) - 15]°C or less. By having a melting point difference of 15°C or more (the melting point of the sheath component is [(melting point of core component) - 15]°C or less), preferably 20°C or more, only the low-melting-point polymer of the sheath component can be bonded during the fiber web formation process, maintaining the strength of the high-melting-point polymer disposed in the core. This results in a nonwoven fabric with excellent mechanical strength. On the other hand, by having the melting point difference of 45°C or less (the melting point of the sheath component is [(melting point of core component) - 45]°C or more), preferably 40°C or less, excessive bonding of the low-melting-point polymer of the sheath component can be suppressed during the fiber web formation process. This prevents a decrease in the specific surface area of ​​the sheath component, resulting in a nonwoven fabric with better moisture absorption and release properties. Furthermore, it also prevents decomposition of the low-melting-point polymer of the sheath component during spinning, thereby suppressing yarn breakage and resulting in a nonwoven fabric with excellent mechanical strength.

[0042] The melting point of the high-melting-point polymer of the core component is preferably 160°C or higher and 320°C or lower. When a nonwoven fabric composed of the core-sheath composite fibers is formed, it has good weaving properties, resulting in a nonwoven fabric with excellent strength and dimensional stability. The lower limit of the melting point range of the high-melting-point polymer of the core component is preferably 160°C or higher, more preferably 170°C or higher, and even more preferably 180°C or higher, resulting in a nonwoven fabric with excellent mechanical strength, dimensional stability, and durability. On the other hand, the upper limit of the melting point range of the high-melting-point polymer of the core component is preferably 320°C or lower, more preferably 300°C or lower, and even more preferably 280°C or lower, thereby reducing the spinning temperature during fabric formation, particularly suppressing decomposition of the copolymerized polyester of the sheath component. Suppressing polymer decomposition reduces thread breakage during spinning, resulting in a nonwoven fabric with even better mechanical strength.

[0043] The melting points of the core component and sheath component of the core-sheath composite fiber constituting the nonwoven fabric are measured and calculated by the following method. (1) A 5 mg measurement sample is taken from the nonwoven fabric, and as a pretreatment, it is melted at 290°C for 5 minutes under a nitrogen stream, and then rapidly cooled to room temperature at 50°C / min. (2) Using a differential scanning calorimeter (DSC, for example, "Q-2000" manufactured by TA Instruments), the melting point is measured under the following conditions. Heating rate: 2°C / min Measurement temperature: -20℃ to 300℃ (3) The melting points (°C) of the core component and sheath component obtained in (2) are rounded to the first decimal place. (4) A measurement sample is again taken from the nonwoven fabric and treated with alkali to dissolve the sheath component, leaving only the core component in the yarn. (5) 5 mg of the sample obtained in (4) is collected and pretreated in the same manner as in (1). (6) The pretreated sample of (5) is subjected to DSC measurement in the same manner as described in (2) to measure the melting point of the core component. (7) Determine the melting point of the sheath component from the melting points obtained in (3) and (6).

[0044] When the fibers constituting the nonwoven fabric of the present invention are core-sheath composite fibers, the composite mass ratio (core:sheath) is preferably 20% by mass or more but less than 100% by mass for the sheath component. By setting the composite mass ratio of the sheath component to preferably 20% by mass or more, more preferably 50% by mass or more, and even more preferably 80% by mass or more, the amount of copolymerized polyester in the nonwoven fabric increases, resulting in a nonwoven fabric with excellent moisture absorption and release properties when used as a humidity conditioner. On the other hand, by setting the composite mass ratio of the core component to preferably 80% by mass or less, more preferably 50% by mass or less, and even more preferably 20% by mass or less, the decrease in the mechanical strength of the nonwoven fabric can be suppressed, resulting in a nonwoven fabric with excellent dimensional stability.

[0045] The core and sheath components of the core-sheath composite fibers contained in the nonwoven fabric of the present invention may contain titanium dioxide (TiO2) particles to reduce friction with various contacting objects such as guides and rollers during the nonwoven fabric manufacturing process, thereby improving processability, adjust the color tone of the product, and improve adhesiveness and thermal conductivity during the fiber web formation process. This reduces thread breakage, resulting in a nonwoven fabric with excellent mechanical strength. The amount of particles added to the polymer and their particle size can be varied depending on the application. However, a content of 0.01% to 10% by mass of the polyester, a number-average particle size of 0.05 μm to 5 μm, and a concentration of coarse particles with a particle size of 4 μm or more in the range of 1,000 particles / 0.4 mg or less are preferred, as they provide particularly good processability, color, and thermal conductivity.

[0046] The single filament fineness of the fibers constituting the nonwoven fabric of the present invention is preferably 0.1 dtex or more and 20 dtex or less. A single filament fineness of preferably 0.1 dtex or more, more preferably 1 dtex or more, stabilizes spinnability during nonwoven fabric production, resulting in a nonwoven fabric with a more uniform basis weight. On the other hand, the upper limit of the single filament fineness is preferably 20 dtex or less, more preferably 10 dtex or less, which increases the number of fibers per unit basis weight and results in a nonwoven fabric with higher mechanical strength. The nonwoven fabric of the present invention may contain a blend of fibers with different finenesses.

[0047] When the density of the polyester constituting the fiber is known, the single fiber fineness can be determined by randomly collecting 10 small samples from the nonwoven fabric, taking photographs at 500 to 3000 magnifications using a scanning electron microscope (for example, the VHX-2000 manufactured by Keyence Corporation), measuring the diameters of 10 single fibers from each sample, a total of 100 single fibers, and then correcting the average value for the density of the polymer and rounding off to one decimal place.

[0048] The average single fiber diameter of the fibers constituting the nonwoven fabric of the present invention is preferably 5.0 μm or more and 50.0 μm or less. By setting the average single fiber diameter to preferably 5.0 μm or more, more preferably 8.0 μm or more, and even more preferably 10.0 μm or more, spinnability during nonwoven fabric production is stabilized, resulting in a nonwoven fabric with uniform basis weight and excellent rigidity. On the other hand, by setting the upper limit of the average single fiber diameter to preferably 50.0 μm or less, more preferably 40.0 μm or less, and even more preferably 35.0 μm or less, the number of fibers per unit basis weight is increased, resulting in a nonwoven fabric with excellent mechanical strength and moisture absorption / desorption properties.

[0049] The nonwoven fabric of the present invention preferably exhibits a fiber diameter change of 1.01 to 2.50 times in a wet state. A fiber diameter change of preferably 1.01 or more, more preferably 1.50 or more, and even more preferably 1.80 or more results in a nonwoven fabric with higher water absorption and excellent moisture absorption. On the other hand, the upper limit of the fiber diameter change is preferably 2.50 or less, more preferably 2.30 or less, and even more preferably 2.10 or less, resulting in a nonwoven fabric in which moisture evaporates quickly from a wet state and the time required to recover the moisture absorption and desorption performance before the wet state is short. Furthermore, volume change when wet can be suppressed, resulting in a nonwoven fabric with excellent dimensional stability.

[0050] The change in fiber diameter is calculated as follows. (1) A 1.0 g measurement sample is taken from the nonwoven fabric and left to stand for 24 hours in a thermo-hygrostat (for example, "LHU-123" manufactured by Espec Corporation) that is regulated at a temperature of 20°C and a humidity of 65% RH. (2) The sample of (1) is observed using an X-ray CT (for example, "nano3DX" manufactured by Rigaku Corporation) and the fiber diameter R1 before wetting is calculated. (3) Take another 1.0 g measurement sample from the nonwoven fabric and immerse it in distilled water at 25°C for 15 minutes. (4) After immersion in distilled water, the sample is attached to tape and fixed on the film, and then the sample is placed in a container filled with distilled water and sealed. (5) The sample of (4) is observed by the X-ray CT of (2) and the fiber diameter R2 after wetting is calculated. (6) The change in fiber diameter is calculated by dividing the fiber diameter after wetting R2 by the fiber diameter before wetting R1. (7) For (2) to (6), a total of 30 fibers are measured, and the arithmetic mean value (times) is calculated by rounding off to two decimal places.

[0051] The change in fiber diameter of the nonwoven fabric in a wet state can be adjusted by the molecular weight and / or copolymerization amount of polyethylene glycol.

[0052] [Nonwoven fabric] Examples of the nonwoven fabric of the present invention include long-fiber nonwoven fabrics, dry-process short-fiber nonwoven fabrics, and paper-made nonwoven fabrics. Among these, long-fiber nonwoven fabrics are preferred because they allow for integrated processing from spinning to winding of the nonwoven fabric, are excellent in productivity and processability, and the strength of the nonwoven fabric is excellent. Long-fiber nonwoven fabrics made from copolymerized polyesters have excellent mechanical strength, and can be used to obtain humidity conditioners with excellent durability.

[0053] The density of the nonwoven fabric of the present invention is 0.01 g / cm 3 More than 0.15g / cm 3 The density is less than 0.01 g / cm 3 or more, preferably 0.05 g / cm 3 More preferably, 0.09 g / cm 3 By setting the density to above 0.15 g / cm, the amount of fiber per unit volume increases, resulting in a nonwoven fabric with excellent moisture absorption and release properties and self-sustaining moisture conditioning properties, as described below. 3 less than 0.13 g / cm 3 or less, more preferably 0.11 g / cm 3 When the thickness is equal to or less than 100 mm, the nonwoven fabric has excellent breathability, quick-drying properties, and dimensional stability.

[0054] The nonwoven fabric of the present invention contains one or more compounds selected from the group consisting of alkali metal halides, alkaline earth metal halides, ammonium halides, and betaine, and the content of the compound is preferably 0.1% by mass or more and 5.0% by mass or less.

[0055] The compound is preferably any one of sodium chloride, potassium chloride, magnesium chloride, calcium chloride, ammonium chloride, and betaine. Among them, sodium chloride, calcium chloride, and betaine are more preferable in terms of ease of handling, suppression of foreign matter generation, and excellent spinning stability. Of course, it is also preferable to contain multiple types of compounds, and for example, sodium chloride, calcium chloride, betaine, etc. may be used in combination.

[0056] The content of the compound is preferably 0.1% by mass or more and 5.0% by mass or less. A content of preferably 0.1% by mass or more, more preferably 1.0% by mass or more, results in a nonwoven fabric with excellent moisture absorption and release properties and the self-sustaining moisture control ability described below. On the other hand, the upper limit of the content is preferably 5.0% by mass or less, more preferably 3.0% by mass or less, which can suppress the generation of foreign matter and improve spinning stability.

[0057] The nonwoven fabric of the present invention preferably has moisture absorptive and desorptive properties. By using a nonwoven fabric having moisture absorptive and desorptive properties, it can be used as a humidity conditioner having self-sustaining humidity control properties.

[0058] The moisture absorption and desorption properties of the nonwoven fabric of the present invention can be evaluated by multiplying the difference between MR2 and MR1 in the following formula (1) by the basis weight m (hereinafter, the value calculated by formula (1) will be referred to as the "moisture absorption amount"). The larger the moisture absorption amount, the higher the moisture absorption and desorption properties and the more self-sustaining moisture control properties can be exhibited. Moisture absorption amount = (MR2-MR1)×m (Formula 1) Here, MR2 is the moisture absorption rate of the nonwoven fabric when the ambient temperature is 30°C and the humidity is 90%RH, MR1 is the moisture absorption rate of the nonwoven fabric when the ambient temperature is 20°C and the humidity is 65%RH, and m is the basis weight of the nonwoven fabric (g / m 2 )

[0059] The moisture absorption amount is 10 g / m 2 The moisture absorption amount is preferably 10 g / m or more. 2 More preferably, 40 g / m 2 More preferably, 70 g / m 2More than 90 g / m 2 By satisfying the above, the nonwoven fabric has high moisture absorption and release properties, and when used as a humidity control material, it can improve the self-sustaining humidity control ability that leads the living space to an appropriate humidity.

[0060] The moisture absorption amount is calculated as follows. (1) Take a 1.0 g measurement sample from the nonwoven fabric and pre-dry it with hot air at 60°C for 30 minutes. (2) After drying in (1), the measurement sample is left to stand for 24 hours in a constant temperature and humidity chamber (such as the "LHU-123" manufactured by Espec Corporation) that is conditioned at a temperature of 20°C and a humidity of 65% RH, and the sample mass W1 after standing is measured. (3) After measuring the mass in (2), the measurement sample is left to stand for 24 hours in a constant temperature and humidity chamber conditioned at a temperature of 30°C and a humidity of 90% RH, and the mass W2 of the sample after standing is measured. (4) After measuring the mass in (3), the measurement sample is dried with hot air at 105°C for 120 minutes, and the mass W3 of the dried sample is measured. (5) Using the sample mass measured in (2), (3), and (4), calculate the moisture absorption rate MR1 when the sample is left standing for 24 hours in an atmosphere at a temperature of 20°C and a humidity of 65% RH, and the moisture absorption rate MR2 when the sample is left standing for 24 hours in an atmosphere at a temperature of 30°C and a humidity of 90% RH using the following formulas i and ii. MR1={(W1-W3) / W3}×100 (formula i) MR2={(W2-W3) / W3}×100 (formula ii) (6) The moisture absorption rates (MR1 and MR2) calculated in (5) and the basis weight (g / m2) calculated by the method described below. 2 ) and calculate the moisture absorption amount (g / m) of the nonwoven fabric from the following formula: 2 ) is calculated using formula iii Moisture absorption amount = (MR2-MR1)×m (Formula iii).

[0061] The moisture absorption capacity of the nonwoven fabric can be adjusted by the molecular weight of polyethylene glycol, the amount of copolymerization, the density of the nonwoven fabric, and / or the addition of a compound.

[0062] The basis weight of the nonwoven fabric of the present invention is 40 g / m 2 More than 800g / m 2 The weight of the nonwoven fabric is preferably 40 g / m or less. 2 More preferably, 200 g / m 2 More preferably, 400 g / m 2 By setting the density to 800 g / m or more, the amount of fiber per unit area increases, resulting in a nonwoven fabric with excellent moisture absorption / release properties and self-sustaining moisture control properties. 2 Less than 500 g / m 2 or less, more preferably 450 g / m 2 When the thickness is equal to or less than 100 μm, the nonwoven fabric has excellent breathability, quick drying properties, and dimensional stability.

[0063] The thickness of the nonwoven fabric of the present invention is preferably 1 mm or more and 30 mm or less. The thickness of the nonwoven fabric is preferably 1 mm or more, more preferably 2 mm or more, and even more preferably 3 mm or more, to provide a nonwoven fabric with excellent mechanical strength and durability. On the other hand, the upper limit of the thickness of the nonwoven fabric is preferably 30 mm or less, more preferably 15 mm or less, and even more preferably 10 mm or less, to provide a nonwoven fabric with reduced rigidity and excellent handleability.

[0064] The breathability of the nonwoven fabric of the present invention is 30 cm 3 / cm 2 The air permeability is preferably 30 cm / s or more. 3 / cm 2 / sec or more, preferably 40cm 3 / cm 2 / sec or more, more preferably 50cm 3 / cm 2 / sec or more, the moisture absorption effect can be demonstrated even within the nonwoven fabric, resulting in a nonwoven fabric with a higher overall moisture absorption capacity.In addition, the moisture release ability after moisture absorption is also improved, resulting in a nonwoven fabric with excellent self-sustaining moisture control properties.

[0065] The air permeability is calculated as follows. (1) Five 20 cm x 20 cm test pieces are taken from the nonwoven fabric and attached to one end (intake side) of the cylinder of a Frangill-type tester (for example, "FX-3340" manufactured by TEXTEST Co., Ltd.). (2) After the test specimen is attached, adjust the suction fan using the rheostat so that the inclined barometer indicates a pressure of 125 Pa. (3) In (2), the amount of air passing through the test piece (cm) is calculated from the pressure indicated by the vertical barometer and the type of air hole used. 3 / cm 2 / seconds). (4) The remaining four test pieces are similarly measured and calculated, and the arithmetic mean value (cm 3 / cm 2 / seconds) to the nearest integer.

[0066] [Nonwoven fabric manufacturing method] The nonwoven fabric of the present invention comprises a step of forming fibers by melt-spinning a copolymer polyester, in which 5% by mass or more and 70% by mass or less of polyethylene glycol having a number average molecular weight of 1,000 to 35,000 is copolymerized, from a spinneret, and a step of depositing the fibers on a moving collecting surface to form a fiber web, and the nonwoven fabric has a density of 0.01 g / cm 3 More than 0.15g / cm 3 Each step of the method for producing a nonwoven fabric will be described in more detail below.

[0067] (Fiber forming process) In this step, a copolymer polyester copolymerized with 5% by mass or more and 70% by mass or less of polyethylene glycol having a number average molecular weight of 1,000 to 35,000 is melt-spun from a spinneret to form fibers.

[0068] The main skeleton portion of this copolymer polyester is a polymer obtained by a condensation reaction of dicarboxylic acid or its ester-forming derivative and diol or its ester-forming derivative as the main components, and therefore the copolymer polyester can be produced by subjecting dicarboxylic acid or its ester-forming derivative and diol or its ester-forming derivative to an esterification reaction or an ester exchange reaction, followed by a polycondensation reaction.

[0069] The timing of addition of polyethylene glycol as a copolymerization component may be any stage, such as before the esterification reaction or transesterification reaction, from the time when the esterification reaction or transesterification reaction is substantially completed until the start of the polycondensation reaction, or after the polycondensation reaction is substantially completed, etc. However, from the viewpoint of obtaining a copolymerized polyester with excellent moisture absorption, it is preferable to add polyethylene glycol from the time when the esterification reaction or transesterification reaction is substantially completed until the start of the polycondensation reaction.

[0070] In the copolymer polyester of the present invention, the method for producing the copolymer polyester preferably involves carrying out an esterification reaction using an aromatic dicarboxylic acid and 1,4-butanediol.

[0071] In the copolymer polyester of the present invention, the number average molecular weight and copolymerization rate of the polyethylene glycol, which is a copolymer component, are as described above.

[0072] The copolymerized polyester of the present invention preferably contains titanium dioxide particles. The titanium dioxide particles are produced by various methods, such as wet and dry methods, and are added to the polyester reaction system after being subjected to pretreatment such as pulverization and classification as necessary. The particles may be added to the polyester reaction system at any stage, but adding the particles after the esterification reaction or transesterification reaction has essentially been completed is preferred because this improves dispersibility in the polymer.

[0073] The copolymerized polyester of the present invention preferably contains one or more compounds selected from the group consisting of alkali metal halides, alkaline earth metal halides, ammonium halides, and betaine. The compounds may be added at any stage, but are preferably added after the esterification reaction or transesterification reaction is substantially completed, since this improves the dispersibility of the compounds in the polymer.

[0074] The copolymer polyester of the present invention, due to its excellent moisture absorption properties, is prone to absorb moisture. When melt-spun, it is preferable to contain an antioxidant to prevent a decrease in yarn strength due to hydrolysis. The antioxidant may be added at any stage, but adding it after the esterification reaction or transesterification reaction is substantially complete is preferable because it prevents the deactivation of the antioxidant and improves resistance to oxidative degradation. Furthermore, the antioxidant is preferably added by melt-kneading the copolymer polyester after production, because this results in a fiber with excellent mechanical properties.

[0075] The type of antioxidant is preferably a phenol-based antioxidant and / or a phosphorus-based antioxidant, and these antioxidants may be used alone or in combination of two or more kinds.

[0076] The phenolic antioxidant is not particularly limited as long as it is a known phenolic antioxidant. Specifically, pentaerythritol-tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenol)propionate) (manufactured by BASF, Irganox® 1010 (IR1010)) and 2,2′-dimethyl-2,2′-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)dipropane-1,1′-diyl bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoate] (manufactured by Sumitomo Chemical Co., Ltd., "SUMILIZER® GA-80") are preferred because of their high effects of inhibiting oxidative decomposition and polymer yellowing.

[0077] The phosphorus-based antioxidant is not particularly limited as long as it is a compound containing phosphorus. Specifically, 4,4'-butylidenebis(3-methyl-6-t-butylphenylditridecylphosphite) (manufactured by Johoku Chemical Industry Co., Ltd., "JPH-1200") is preferred because it can reduce the number of yarn breaks during spinning.

[0078] The polyester prepared by the above method is melt-spun from a spinneret to form fibers. In this case, it is preferable that the copolymerized polyester copolymerized with polyethylene glycol is vacuum-dried, then melt-metered in an extruder, and fed to a spinneret to be spun into long fibers. Furthermore, it is preferable that the step of forming the fibers is a spunbonding method or a melt-blowing method.

[0079] In the spunbonding method, a resin is melted and spun through a spinneret, and the resulting filaments are cooled and solidified. The resulting filaments are then drawn and stretched by compressed air injected from an ejector installed below the spinneret without being wound up. The spinneret and ejector may be of various shapes, such as round or rectangular. A preferred embodiment of the method is to use a combination of a rectangular spinneret and a rectangular ejector, since this method uses a relatively small amount of compressed air and is less likely to cause fusion or friction between the filaments.

[0080] In the melt-blowing method, a resin is melted and spun from a spinneret, and hot air is sprayed at a certain angle onto the discharge port to refine the fibers. The spinneret that can be used may be round, triangular, rectangular, Y-shaped, or the like. Among these, round discharge ports are preferred because they offer excellent process stability during the spinning process.

[0081] In order to improve the strength of the long fibers, which contributes to the mechanical strength of the nonwoven fabric, and to suppress deformation such as bending and curling of the nonwoven fabric, the spinning speed is preferably 2000 m / min or more and 5500 m / min or less. By setting the spinning speed to preferably 2000 m / min or more, more preferably 3000 m / min or more, and even more preferably 3500 m / min or more, the long fibers can be oriented and crystallized to a higher degree. On the other hand, in order to suppress excessive orientation and crystallization of the long fibers, the spinning speed is preferably set to 5500 m / min or less, more preferably 5000 m / min or less, and even more preferably 4500 m / min or less. The spinning speed can be controlled in the spunbonding method by adjusting the suction pressure during suction drawing using high-speed suction gas, and in the meltblowing method by adjusting the hot air volume.

[0082] (Process for forming a fiber web) In this process, the fibers obtained in the previous process are deposited on a moving collecting surface to form a fiber web composed of copolymer polyester. Specifically, the copolymer polyester fibers are landed on a net conveyor that is sucked by air from the back side, and collected as a fiber web.

[0083] The collected fiber web is preferably transported at a transport speed of 5 m / min or more and 1200 m / min or less.

[0084] The material of the net used for collection is not particularly limited, and examples include metal nets such as stainless steel, iron, and nickel, as well as resin nets made of polyester or fluororesin, rubber nets, etc. Among these, it is preferable to use a resin net from the viewpoint of collection properties and releasability from the conveyor.

[0085] In another preferred embodiment, the collected fiber web is temporarily bonded by contacting one side of the web with a hot flat roll on a net, which prevents the surface layer of the fiber web from turning over or being blown away while being transported on the net, thereby improving transportability from collection of the yarns to thermal bonding.

[0086] Furthermore, it is preferable to laminate a plurality of layers of collected fiber webs or thermally bonded nonwoven fabrics, since this improves productivity and uniformity of texture.

[0087] (Process for integrating the fiber web) Furthermore, it is also preferable to subject the fiber web obtained in the previous step to the following [i] or [ii]. In this case, it is also preferable to use a fiber web in which multiple layers are laminated.

[0088] ([i] Step of three-dimensionally entangling the fiber web) The process may include a step of three-dimensionally entangling the fiber web obtained in the previous step. Specifically, needle punching or water jet punching is preferred because it allows the density to be maintained within a desired range. Among these, needle punching is preferred because it provides strong entanglement and high dimensional stability after moisture absorption and desorption.

[0089] ([ii] Step of thermally bonding the fiber web) In addition, the process may include a step of continuously thermally bonding the fiber web obtained in the (step of forming a fiber web). Specifically, preferred methods involve heat-sealing using various rolls, such as a heat-embossing roll, a pair of upper and lower rolls each having an engraved (uneven) surface, a heat-embossing roll consisting of a combination of a roll with one flat (smooth) surface and a roll with an engraved (uneven) surface, and a heat-calendering roll consisting of a pair of upper and lower flat (smooth) rolls. Among these, it is preferred to use a heat-embossing roll, a pair of upper and lower rolls each having an engraved (uneven) surface, or a heat-embossing roll consisting of a combination of a roll with one flat (smooth) surface and a roll with an engraved (uneven) surface. This not only increases productivity but also allows for the formation of bonded sections that improve the strength of the nonwoven fabric and non-bonded sections that allow for control of texture and density.

[0090] (Other post-processing processes) The nonwoven fabric of the present invention can be post-processed to the extent that the effects of the present invention are not impaired. Examples of post-processing include physical processing such as drilling and rubbing, and chemical processing such as hydrophilic treatment, electrostatic treatment, and antibacterial treatment. Of course, in the present invention, nonwoven fabrics obtained by performing these post-processing steps are also considered to be nonwoven fabrics of the present invention.

[0091] [Uses of nonwoven fabric] The nonwoven fabric of the present invention can be a nonwoven fabric obtained by three-dimensionally entanglement of long-fiber nonwoven fabrics, and exhibits excellent moisture absorption and release properties and self-sustaining humidity control properties, so it is preferable to use the nonwoven fabric as a humidity control material.

[0092] This humidity-conditioning material can be used as a building material as an interior sheet inserted under the floor, ceiling, or wall of a house, warehouse, or transport shed, as well as in vehicle interior materials, household humidity-conditioning materials used in containers or storage, bedding, clothing, etc. In particular, because of its property of removing excess moisture in high-humidity environments that make people uncomfortable and providing a comfortable space, it is suitably used for residential building materials and vehicle interior materials.

[0093] When the nonwoven fabric of the present invention is used for applications such as residential building materials or automotive interior materials, it is also preferable to form a laminate comprising the humidity control material and a heat insulating material, which can easily adjust the humidity and temperature in the space to a level that people feel comfortable. [Example]

[0094] The nonwoven fabric of the present invention will be specifically described below based on examples, but of course, these are merely examples and the present invention is not limited to these.

[0095] [Measurement method] The physical properties of the nonwoven fabric and the fibers constituting the nonwoven fabric, as well as the physical properties in the examples, were measured by the following methods. However, unless otherwise specified, the physical properties were measured according to the above-mentioned methods.

[0096] (1) Melting point of polymer (℃) The melting point of the polymer was measured and calculated by the above-mentioned method using a differential scanning calorimeter (DSC) "Q-2000" manufactured by TA Instruments.

[0097] (2) Molecular weight of polyethylene glycol (PEG) The molecular weight of polyethylene glycol was measured and calculated by the above-mentioned method using a differential refractive index detector "RID-20A" manufactured by Shimadzu Corporation as a measuring device for gel permeation chromatography (GPC).

[0098] (3) Copolymerization rate (mass%) of PEG in the fibers constituting the nonwoven fabric The copolymerization rate of PEG was measured and calculated by the above-mentioned method using a measuring device "AL-400" manufactured by JEOL Ltd.

[0099] (4) Average single yarn fineness (dtex) The average single yarn fineness was measured and calculated using a scanning electron microscope "VHX-2000" manufactured by Keyence Corporation according to the method for measuring the single yarn fineness described above.

[0100] (5) Weight of nonwoven fabric (g / m 2 ) The basis weight was determined by taking three 30 cm x 50 cm pieces of nonwoven fabric, measuring the mass of each sample, and converting the average of the obtained values ​​into a value per unit area, and rounding off to the first decimal place.

[0101] (6) Thickness of nonwoven fabric (mm) The thickness of the nonwoven fabric was measured by randomly collecting 10 small samples, clamping the nonwoven fabric sample between an anvil and spindle with a diameter of 6 mm using a micrometer manufactured by Mitutoyo Corporation, measuring two points at equal intervals within the small sample to the nearest 0.01 mm, and rounding off the average value of a total of 20 points to the nearest 1 decimal place.

[0102] (7) Density of nonwoven fabric (g / cm 3 ) The basis weight of the nonwoven fabric was divided by the thickness of the nonwoven fabric, and the result was rounded off to two decimal places.

[0103] (8) Breathability of nonwoven fabric (cm 3 / cm 2 / sec) The breathability of the nonwoven fabric was measured by the above-mentioned method using a Frangill type tester "FX-3340" manufactured by TEXTEST Co., Ltd.

[0104] (9) Change in fiber diameter of nonwoven fabric (fold) The change in fiber diameter of the nonwoven fabric was measured using the X-ray CT "nano3DX" manufactured by Rigaku Corporation by the above-mentioned method.

[0105] (10) Moisture absorption of nonwoven fabric (g / m 2 ) The moisture absorption amount of the nonwoven fabric was measured and calculated using a thermo-hygrostat (such as "LHU-123" manufactured by Espec Corporation) according to the method described in the specification.

[0106] (11) Self-sustaining humidity control of nonwoven fabric The self-sustaining moisture conditioning ability of the nonwoven fabric was evaluated on a five-level scale from SS to C according to the amount of moisture absorption described above. · SS: With a moisture absorption capacity of 90 or more, it has excellent performance in maintaining the appropriate humidity level in living spaces, making it suitable for use as a humidity control material. · S: The moisture absorption capacity is 70 or more, and it has excellent performance in maintaining the appropriate humidity level in living spaces, making it suitable for use as a humidity control material. A: The moisture absorption amount is 40 or more, and it has the ability to maintain the appropriate humidity level in living spaces, so it can be used as a humidity control material. B: The moisture absorption rate is 10 or more, and the performance of maintaining the appropriate humidity level in a living space is somewhat inferior, but it can be used as a humidity control material. C: The moisture absorption amount is less than 10, and the performance of maintaining the appropriate humidity in the living space is poor, making it difficult to use as a humidity control material.

[0107] (12) Dimensional stability of nonwoven fabric The dimensional stability of the nonwoven fabric was evaluated by the thickness ratio of the nonwoven fabric at each temperature and humidity. Specifically, the thickness ratio was calculated by measuring the thickness (L1) of the nonwoven fabric when conditioned at 20°C and 65% RH and the thickness (L2) of the nonwoven fabric when conditioned at 30°C and 90% RH using the method described above (6). Thickness ratio = L2 / L1 (formula) Then, the thickness ratio was evaluated on a scale of S to C. · The S:thickness ratio is less than 1.10, and dimensional changes during moisture absorption and desorption can be sufficiently suppressed, making it suitable for use as a humidity conditioner. A: The thickness ratio is 1.10 or more and less than 1.20, and dimensional changes during moisture absorption and desorption can be suppressed, making it suitable for use as a humidity conditioner. · B: The thickness ratio is 1.20 or more and less than 1.30, and although dimensional changes occur when absorbing and releasing moisture, the effects are not significant, so the film can be used as a humidity-regulating material. C: The thickness ratio is 1.30 or more, and the dimensional change during moisture absorption and release is large, making it difficult to use as a humidity-regulating material.

[0108] (13) Quick-drying nonwoven fabric The quick-drying property of the nonwoven fabric was evaluated by the residual moisture content. Specifically, a test piece of 1 g (W'1) was cut out from a nonwoven fabric that had been conditioned at 20°C and 65% RH for 24 hours, immersed in distilled water for 15 minutes, and then centrifuged to remove the moisture adhering to the surface of the nonwoven fabric. After that, the nonwoven fabric was left to stand in an environment of 20°C and 50% RH, and the mass (W'2) was measured and calculated using the following formula: Residual moisture percentage (%)=((W'2 / W'1)-1)×100 (formula) The time required for the residual moisture content to reach 1% or less was evaluated on a 4-level scale from S to C. ·S: The time required for the residual moisture content to reach 1% or less is less than 1 hour, and the moisture release performance is very excellent, making it suitable for use as a humidity conditioner. A: The time required for the residual moisture content to reach 1% or less is 1 hour or more and less than 1.5 hours, and the moisture release performance is excellent, making it suitable for use as a humidity conditioner. B: The time required for the residual moisture content to reach 1% or less is 1.5 hours or more but less than 2 hours. The moisture release performance is slightly inferior, but the impact is not significant, and the material can be used as a humidity control material. C: It takes more than 2 hours for the residual moisture content to reach 1% or less, and the moisture release performance is poor, making it difficult to use as a humidity control material.

[0109] (14) Moisture-regulating properties of nonwoven fabrics The moisture conditioning ability of the nonwoven fabric was evaluated by the following method. Specifically, a test piece was cut out from the nonwoven fabric so that the moisture absorption amount was 0.20 g, and the sample was dried with hot air at 105°C for 30 minutes. Thereafter, the moisture was conditioned at 23°C and 95% RH. 2 The sample was placed in the sealed container, and the time it took for the humidity inside the sealed container to fall below 70% RH was measured until it fell below 60% RH. The sample was evaluated on a four-level scale from S to C according to the time it took. · S: The time required for the humidity to drop below 60% RH is 12 hours or more, which is within the range where humidity does not decrease in the living space, and the material can be suitably used as a humidity conditioner. A: The time required for the humidity to drop below 60% RH is 6 hours or more and less than 12 hours, which is within the range that does not affect the low humidity in living spaces, and the material can be suitably used as a humidity-conditioning material. B: The time required for the humidity to drop below 60% RH is between 2 and 6 hours, and the humidity in the living space is slightly lowered, but not significantly, so the material can be used as a humidity-regulating material. C: It takes less than two hours for the humidity to drop below 60% RH, which may affect the humidity level in living spaces, making it difficult to use as a humidity-regulating material.

[0110] [polyester] The polyesters (copolyesters) used in the examples and comparative examples were obtained as follows.

[0111] (Polyester A) Butanediol (BDO) was heated to 100°C, and then a titanium catalyst, tetra-n-butoxytitanate (TBT) (manufactured by Tokyo Chemical Industry Co., Ltd.), was mixed to obtain a catalyst solution.

[0112] Terephthalic acid (TPA) (manufactured by Tokyo Chemical Industry Co., Ltd.) as the dicarboxylic acid component, butanediol (BDO) (manufactured by Tokyo Chemical Industry Co., Ltd.) as the diol component, and the catalyst solution obtained by the above method as the esterification reaction catalyst were charged into an esterification reactor equipped with a rectification column. After the esterification reaction was initiated under a reduced pressure of 93 kPa at a temperature of 160°C, the esterification reaction was finally carried out under conditions of a temperature of 235°C, and after completion of the esterification reaction, initial polymerization (500 torr x 60 minutes) was carried out.

[0113] Polyethylene glycol (PEG) with a number-average molecular weight of 1000 ("PEG1000" manufactured by Sanyo Chemical Industries, Ltd.) was added to the polycondensation tank at 50% by mass. Furthermore, an antioxidant, pentaerythritol-tetrakis(3-(3,5-di-t-butyl-4-hydroxyphenol)propionate) (Irganox® 1010 manufactured by BASF) and a titanium oxide slurry were added to the polycondensation tank, and the reaction product obtained in the esterification reaction tank was transferred. After the temperature of the polycondensation tank reached 250°C, the catalyst solution obtained by the above method was added as a polycondensation reaction catalyst, and a polycondensation reaction was carried out to obtain a copolymerized polybutylene terephthalate (PBT-PEG) with a melting point of 220°C and containing 0.2% by mass of titanium oxide.

[0114] Next, the obtained PBT-PEG was blended with 2,2'-dimethyl-2,2'-(2,4,8,10-tetraoxaspiro[5.5]undecane-3,9-diyl)dipropane-1,1'-diyl bis[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)propanoate] (manufactured by Sumitomo Chemical Co., Ltd., "SUMILIZER" (registered trademark) GA-80) as a phenolic antioxidant and 4,4'-butylidenebis(3-methyl-6-t-butylphenylditridecylphosphite) (manufactured by Johoku Chemical Industry Co., Ltd., JPH-1200) as a phosphorus-based antioxidant, and the blend was melt-kneaded to obtain Polyester A.

[0115] (Polyester B to E) Polyesters B to E were obtained in the same manner as polyester A, except that polyester A used polyethylene glycol (PEG) with a number average molecular weight of 1,000, polyester B used PEG with a number average molecular weight of 3,400 ("PEG4000S" manufactured by Sanyo Chemical Industries, Ltd.), polyester C used PEG with a number average molecular weight of 8,300 ("PEG6000S" manufactured by Sanyo Chemical Industries, Ltd.), polyester D used PEG with a number average molecular weight of 20,000 ("PEG20000" manufactured by Sanyo Chemical Industries, Ltd.), and polyester E used PEG with a number average molecular weight of 35,000 ("PEG35000" manufactured by Sigma-Aldrich).

[0116] (Polyester F~N) In polyester C, the copolymerization rate of PEG with a number average molecular weight of 8,300 ("PEG6000S" manufactured by Sanyo Chemical Industries, Ltd.) was 50 mass%, but the PEG copolymerization rate was changed as shown in Table 1. Copolymer polyesters F to N were obtained in the same manner as copolymer polyester C.

[0117] (Polyester O-T) Copolymer polyesters O to T were obtained in the same manner as copolymer polyester C, except that alkali metal halides and the like were further added to polyester C in amounts as shown in Table 1.

[0118] (Polyester X) Polyester X was obtained in the same manner as Polyester A, except that in the step of obtaining Polyester A, polyethylene glycol (PEG) having a number average molecular weight of 1000 ("PEG1000" manufactured by Sanyo Chemical Industries, Ltd.) was not added.

[0119] (Polyester Y) In an esterification reactor, bis-2-hydroxyethyl terephthalate and its oligomers were melted at 250°C under atmospheric pressure. A mixed slurry of terephthalic acid (TPA) (Tokyo Chemical Industry Co., Ltd.) as a dicarboxylic acid component and ethylene glycol (EDO) (Mitsubishi Chemical Corporation) as a diol component was sequentially added under atmospheric pressure and temperature control at 240-250°C. The generated water was distilled off, resulting in the esterification reaction, yielding bis-2-hydroxyethyl terephthalate and its oligomers. Half of the resulting bis-2-hydroxyethyl terephthalate oligomers was transferred to a polycondensation reactor. After the temperature of the polycondensation reactor reached 250°C, antimony trioxide was added as a polycondensation catalyst, cobalt acetate and phosphoric acid as additives, and titanium dioxide slurry as a pigment. Polycondensation reaction was then carried out to yield Polyester Y, a polyethylene terephthalate (PET) (not a copolymer) with a melting point of 255°C and containing 0.3% by weight of titanium dioxide.

[0120] [Table 1]

[0121] [Example 1] (Fiber forming process) The polyester A was melt-extruded using a single-screw extruder and metered using a gear pump, and then fed to a rectangular spinneret at a spinneret temperature of 250°C. After spinning, the resulting mixture was sucked by an ejector at a spinning speed of 4000 m / min to obtain fibers.

[0122] (Process for forming a fiber web) Subsequently, the obtained fibers were landed on a net conveyer that was sucked by air from the back side to obtain a fiber web made of polyester A. Thereafter, the collected fiber web was transported at a speed of 10 m / min.

[0123] (A process for three-dimensionally entangling a fiber web) Subsequently, a dimethyl silicone smoothing agent was sprayed onto the fiber web made of polyester A obtained as described above at a concentration of 0.05% by mass relative to the fiber component, and the needle density was 100 times / cm. 2 The needle punching process was carried out under the conditions of 420 g / m 2 , thickness 4.2mm, density 0.10g / cm 3 The results are shown in Table 2.

[0124] The air permeability of the obtained nonwoven fabric was 58 cm 3 / cm 2 / sec, the fiber diameter change was 1.20 times, and the moisture absorption amount was 20.

[0125] [Example 2-5] Nonwoven fabrics were obtained in the same manner as in Example 1, except that in the (step of forming fibers) polyester B to polyester E were used instead of polyester A. The results are shown in Table 2.

[0126] By increasing the number average molecular weight of the PEG copolymer polyester from 1,000 (Example 1) to 8,300 (Example 3), the moisture absorption amount increased to 84, and the self-sustaining moisture control and humidity conditioning properties tended to improve. Furthermore, by further increasing the number average molecular weight to 35,000 (Example 5), the moisture absorption amount increased to 97, but there was a large amount of thick and thin fibers during spinning, and spinnability tended to decrease.

[0127] [Table 2]

[0128] [Examples 6-12] Nonwoven fabrics were obtained in the same manner as in Example 3, except that in the (step of forming fibers) polyester F to L were used instead of polyester C. The results are shown in Table 3.

[0129] By decreasing the copolymerization rate of PEG in the copolyester from 50% by mass (Example 3) to 5% by mass (Example 6), the moisture absorption amount tended to decrease to 16. On the other hand, by increasing the copolymerization rate of PEG to 70% by mass (Example 12), the moisture absorption amount increased to 118, but spinnability tended to decrease due to the generation of thick and thin fibers during spinning, and dimensional stability and quick-drying properties tended to decrease.

[0130] [Comparative Example 1] A nonwoven fabric was obtained in the same manner as in Example 3, except that in the (step of forming fibers) polyester X was used instead of polyester A. The results are shown in Table 3.

[0131] The nonwoven fabric obtained in Comparative Example 1 was not copolymerized with PEG, and therefore had a low moisture absorption amount and was poor in self-sustaining moisture absorption and moisture conditioning properties.

[0132] [Comparative Examples 2 and 3] Nonwoven fabrics were obtained in the same manner as in Example 3, except that in the (step of forming fibers) polyester M and polyester N were used instead of polyester C. The results are shown in Table 3.

[0133] The nonwoven fabric obtained in Comparative Example 2 had a low moisture absorption amount and was poor in self-sustaining moisture absorption and moisture conditioning properties due to the low copolymerization rate of PEG in the copolymer polyester.

[0134] The nonwoven fabric obtained in Comparative Example 3 had poor spinnability due to the occurrence of thick and thin fibers during spinning caused by an excessive copolymerization rate of PEG in the copolyester. In addition, the amount of moisture absorption was very high, and the fabric had poor dimensional stability and quick-drying properties.

[0135] [Table 3]

[0136] [Examples 13-16] In the (step of forming a fiber web), nonwoven fabrics were obtained in the same manner as in Example 3, except that the basis weight during nonwoven fabric production was changed as shown in Table 4 so that the density of the nonwoven fabric would be as shown in Table 4. The results are shown in Table 4.

[0137] The density of the nonwoven fabric is 0.10 g / cm 3 (Example 3) to 0.01 g / cm 3 (Example 13) 3 / cm 2 / sec, but the moisture absorption rate tended to decrease to 10 as the amount of yarn in the nonwoven fabric decreased. On the other hand, when the density was increased to 0.15 g / cm 3 When the air permeability is increased to 30 cm 3 / cm 2 / sec, but as the amount of yarn in the nonwoven fabric increased, the moisture absorption rate tended to increase up to 125. Also, dimensional stability and quick-drying properties tended to decrease.

[0138] [Comparative Examples 4 and 5] In the (step of forming a fiber web), nonwoven fabrics were obtained in the same manner as in Example 3, except that the basis weight during nonwoven fabric production was changed as shown in Table 4 so that the density of the nonwoven fabric would be as shown in Table 4. The results are shown in Table 4.

[0139] The nonwoven fabric obtained in Comparative Example 4 had a low moisture absorption amount and was poor in self-sustaining moisture absorption and moisture conditioning properties due to the low density of the nonwoven fabric.

[0140] The nonwoven fabric obtained in Comparative Example 5 was inferior in breathability, dimensional stability, and quick-drying property due to an excessively high density of the nonwoven fabric.

[0141] [Example 17] A nonwoven fabric was obtained in the same manner as in Example 3, except that in the step of three-dimensionally entangling the fiber web, the bonding method for the nonwoven fabric was changed from the needle punch method to the water jet method. The results are shown in Table 4.

[0142] By changing the adhesive method from the needle punch method (Example 3) to the water jet method (Example 17), there was no change in the amount of moisture absorption, but the adhesiveness decreased, and the dimensional stability and quick-drying properties tended to decrease.

[0143] Comparative Example 6 In the process of three-dimensionally entangling the fiber web, the bonding method of the nonwoven fabric was changed from the needle punch method to a thermocompression bonding method in which the nonwoven fabric is passed between a metal uneven roll with perfectly circular convex portions uniformly arranged in a houndstooth pattern as the upper roll and a flat roll as the lower roll, and the surface temperature of the upper and lower rolls is 170°C and the linear pressure is 588 N / cm. Furthermore, the density of the nonwoven fabric is changed to 0.50 g / cm. 3 A nonwoven fabric was obtained in the same manner as in Example 3, except that the above-mentioned change was made. The results are shown in Table 4.

[0144] The nonwoven fabric obtained in Comparative Example 6 had a low moisture absorption capacity and poor self-sustaining moisture absorption and moisture conditioning properties due to the thickness of the nonwoven fabric being thin and the high density of the nonwoven fabric caused by excessive bonding of the nonwoven fabric pieces together by thermocompression bonding.

[0145] [Table 4]

[0146] [Examples 18-23] Nonwoven fabrics were obtained in the same manner as in Example 3, except that in the (step of forming fibers) polyester O to P were used instead of polyester C. The results are shown in Table 5.

[0147] By adding 1.0 mass % sodium chloride (Example 19) to Example 3, which did not contain any compound such as an alkali metal halide, the moisture absorption amount tended to increase to 90 without any change in spinnability. On the other hand, when 5.0 mass % sodium chloride (Example 21) was added, the moisture absorption amount increased to 125 g / m 2 However, the added sodium chloride became a foreign substance, which resulted in many thread breaks during spinning and a tendency for spinnability to decrease.

[0148] On the other hand, the addition of calcium chloride or betaine tended to increase the moisture absorption without affecting the spinnability.

[0149] [Table 5]

[0150] [Examples 24-26] A nonwoven fabric was obtained in the same manner as in Example 3, except that the (fiber forming step) was changed as follows. The results are shown in Table 6.

[0151] (Fiber forming process) Polyester Y was used as the core component, and polyester C was used as the sheath component. The core component and sheath component were melted at 290°C and 250°C, respectively, and spun out of fine holes at a spinneret temperature of 290°C in a core:sheath mass ratio of 80:20 (Example 24), 50:50 (Example 25), or 20:80 (Example 26). The spinning was then carried out using an ejector at a spinning speed of 4000 m / min to spin concentric sheath-core filaments (circular cross section) whose entire surface was covered with polyester C.

[0152] By changing the fibers constituting the nonwoven fabric from polyester C single fibers (Example 3) to polyester Y / polyester C core-sheath composite fibers, the strength of the nonwoven fabric improved, but the moisture absorption capacity tended to decrease due to the reduced ratio of polyester C.

[0153] [Table 6]

Claims

1. A nonwoven fabric made of fibers containing polyester, the polyester is a copolymerized polyester obtained by copolymerizing 5% by mass or more and 70% by mass or less of polyethylene glycol having a number average molecular weight of 1,000 to 35,000, The density of the nonwoven fabric is 0.01 g / cm ３ 0.15g / cm or more ３ Less than 100% nonwoven fabric.

2. 2. The nonwoven fabric according to claim 1, wherein the copolymerized polyester has a polyester structure consisting of repeating units of an esterification reaction product of an aromatic dicarboxylic acid and an alkylene glycol, and the alkylene glycol is 1,4-butanediol.

3. 3. The nonwoven fabric according to claim 1, wherein the fiber diameter change in a wet state is 1.01 times or more and 2.50 times or less.

4. The nonwoven fabric according to claim 1 or 2, wherein the nonwoven fabric is three-dimensionally entangled.

5. 3. The nonwoven fabric according to claim 1, wherein the nonwoven fabric contains one or more compounds selected from the group consisting of alkali metal halides, alkaline earth metal halides, ammonium halides, and betaine, and the content of the compounds is 0.1% by mass or more and 5.0% by mass or less.

6. The nonwoven fabric according to claim 1 or 2, wherein the nonwoven fabric satisfies the following formula 1: (MR ２ - MR １ ) × m ≥ 10 ··· (Equation 1) Here, MR ２ is the moisture absorption rate of the nonwoven fabric at an ambient temperature of 30°C and a humidity of 90% RH. MR １ is the moisture absorption rate of the nonwoven fabric at an ambient temperature of 20°C and a humidity of 65% RH, m is the basis weight of the nonwoven fabric (g / m ２ )

7. The nonwoven fabric according to claim 1 or 2, wherein the nonwoven fabric is a long-fiber nonwoven fabric.

8. A humidity conditioner comprising the nonwoven fabric according to claim 1 or 2.

9. A laminate comprising the humidity conditioner according to claim 8 and a heat insulating material.

10. a step of melt-spinning a copolymer polyester obtained by copolymerizing 5% by mass or more and 70% by mass or less of polyethylene glycol having a number average molecular weight of 1,000 to 35,000 from a spinneret to form a fiber; and depositing the fibers onto a moving collection surface to form a fibrous web; Density is 0.01 g / cm ３ 0.15g / cm or more ３ The method of claim 1 , wherein the nonwoven fabric is formed having a thickness of less than 1 / 2 mm.

11. The method for producing a nonwoven fabric according to claim 10, wherein the step of forming the fibers is a spunbonding method or a meltblowing method.

12. The method for producing a nonwoven fabric according to claim 10 or 11, further comprising a step of three-dimensionally entangling the formed fiber web.

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