Polyester resin composition, polyester nonwoven fabric, and method for producing the same.

Abstract

To provide a polyester nonwoven fabric having suppressed shrinkage ratio under a high temperature environment at low cost and a polyester resin suitable for the nonwoven fabric.SOLUTION: A nonwoven fabric formed of fibers of polyester resin composition is provided. The polyester resin composition includes 90 mass% or more of a first resin with respect to mass of the polyester resin composition. The first resin is a polymer of an acid component and an alcohol component. The acid component includes 90 mol% or more of a terephthalic acid component with respect to total amount of the acid component. The alcohol component includes 90 mol% or more of an ethylene glycol component with respect to total amount of the alcohol component. The polyester resin composition constituting the nonwoven fabric satisfies followings 1) to 3): 1) having 0.25 to 0.45 of intrinsic viscosity; 2) having 250°C to 260°C of melting point; and 3) having 185°C to 235°C of temperature-falling crystallization temperature.SELECTED DRAWING: None

Description

Technical Field

[0001] The present disclosure relates to polyester resins composition and also relates to nonwoven fabrics and methods for producing the same. polyester

Background Art

[0002] teeth As nonwoven fabrics made from thermoplastic resins by there are, for example, melt-blown nonwoven fabrics produced by the melt-blown method. Melt-blown nonwoven fabrics are used in various applications such as filters, sound-absorbing materials, and heat-insulating materials.

[0003] of The melt-blown method is a process for producing a web of ultrafine fibers directly from a thermoplastic polymer. In a typical example of the production process of the melt-blown method, the molten thermoplastic polymer is passed through a die including small-diameter orifices arranged densely, and the material refined into ultrafine fibers by hot air at high temperature and high speed is accumulated to obtain a melt-blown nonwoven fabric

[0004] sex I ended up doing it. but heat

[0005]

[0006] It is insufficient. Therefore, heat Meltblown nonwoven fabrics with suppressed shrinkage rates are known (see, for example, Patent Documents 1 and 2).

[0005] Patent Document 1 describes a heat-stable nonwoven web comprising meltblown fibers, each of which is a blend polymer fiber containing a blend of poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET), exhibiting an average weight ratio of PBT to PET of about 35:65 to about 65:35; and short fibers constituting about 10% to about 60% by weight of the total weight of the fiber material of the web, wherein the heat-stable nonwoven web exhibits a thermal shrinkage of less than about 10%.

[0006] Patent Document 2 describes a method for producing a meltblown nonwoven fabric in which a meltblown nonwoven fabric made of polyethylene terephthalate meltblown fibers is subjected to dry heat treatment at 180°C or lower to obtain a meltblown nonwoven fabric with a hot water surface shrinkage rate of 20% or less. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Special Publication No. 2017-519127 [Patent Document 2] Japanese Patent Application Publication No. 3-45768 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] The following analysis is given from the perspective of this disclosure.

[0009] In the heat-stable nonwoven web described in Patent Document 1, PET is mixed with 35% by mass or more of PBT to obtain a level of heat shrinkage equivalent to that of PBT. However, in some cases thereFurthermore, since it uses expensive PBT, the cost advantage is not significant. Also, when PET is mixed with other resins, the melting point of the mixed resin is generally lower than that of PET. For this reason, the heat-stable nonwoven fabric web described in Patent Document 1 has a lower melting point than the PET meltblown nonwoven fabric.

[0010] In the manufacturing method for meltblown nonwoven fabric described in Patent Document 2, the degree of crystallinity of PET is increased by annealing the nonwoven fabric after its production. However, such a method requires processes and equipment for annealing, which is undesirable from the standpoint of manufacturing costs.

[0011] Therefore, there is a need for inexpensive materials with a high melting point and a crystallization rate suitable for the meltblown process, as well as nonwoven fabrics with a low thermal shrinkage rate in high-temperature environments. [Means for solving the problem]

[0012] According to one aspect of the present invention, a nonwoven fabric made of fibers of a polyester resin composition is provided. The polyester resin composition is a first resin comprising 90% by mass or more of the total mass of the polyester resin composition. and talc powder and / or acetate powder The first resin is a polymer of an acid component and an alcohol component. The acid component contains 90 mol% or more of terephthalic acid relative to the total amount of acid components. The alcohol component contains 90 mol% or more of ethylene glycol relative to the total amount of alcohol components. The talc powder is present in an amount of 0.3% to 7% by mass relative to the mass of the polyester resin composition. The acetate powder is present in an amount of 0.05% to 0.5% by mass relative to the mass of the polyester resin composition. The nonwoven fabric is a meltblown nonwoven fabric. The polyester resin composition constituting the nonwoven fabric satisfies the following conditions 1) to 3). 1) 0.25 dl / g ~0.45 dl / g It has an intrinsic viscosity; 2) It has a melting point of 250°C to 260°C; 3) It has a cooling crystallization temperature of 185°C to 235°C.

[0013] According to a second aspect of the present invention, a polyester resin for manufacturing nonwoven fabrics composition It will be provided. The polyester resin composition contains a first resin in an amount of 90% by mass or more relative to the mass of the polyester resin composition, and talc powder and / or acetate powder. The first resin is a polymer of an acid component and an alcohol component. The acid component contains 90 mol% or more of terephthalic acid component relative to the total amount of acid components. The alcohol component contains 90 mol% or more of ethylene glycol component relative to the total amount of alcohol components. The talc powder is in an amount of 0.3% to 7% by mass relative to the mass of the polyester resin composition. The acetate powder is in an amount of 0.05% to 0.5% by mass relative to the mass of the polyester resin composition. The nonwoven fabric is a meltblown nonwoven fabric. Polyester resin compositionsatisfies the following a) to c): a) having an intrinsic viscosity of 0.30 dl / g to 0.50 dl / g; b) having a melting point of 250°C to 260°C; c) having a crystallization temperature on cooling of 185°C to 235°C.

[0014] According to a third aspect of the present invention, Add talc powder and / or acetate powder to the polyester resin. a polyester resin satisfying the following a) to c) composition is prepared, and a nonwoven fabric manufacturing step of manufacturing a polyester nonwoven fabric from the polyester resin composition are included, and a method for manufacturing a polyester nonwoven fabric is provided. The talc powder is present in an amount of 0.3% to 7% by mass relative to the total mass of the polyester resin and talc powder. The acetate powder is present in an amount of 0.05% to 0.5% by mass relative to the total mass of the polyester resin and acetate powder. The polyester nonwoven fabric is a meltblown nonwoven fabric. The method for manufacturing a polyester nonwoven fabric does not include a heating step of heating the nonwoven fabric at a temperature of 150°C or higher: a) having an intrinsic viscosity of 0.30 dl / g to 0.50 dl / g; b) having a melting point of 250°C to 260°C; c) having a crystallization temperature on cooling of 185°C to 235°C.

Effects of the Invention

[0015] The polyester nonwoven fabric of the present disclosure has high heat resistance.

[0016] The polyester resin of the present disclosure composition is suitable for manufacturing a polyester nonwoven fabric with high heat resistance.

[0017] According to the method for manufacturing a polyester nonwoven fabric of the present disclosure, a polyester nonwoven fabric with high heat resistance can be manufactured without requiring a heating step after nonwoven fabric production.

[0018] The nonwoven fabric of the present disclosure polyester has high heat resistance.

Modes for Carrying Out the Invention

[0019] Preferred forms of each of the above aspects are described below.

[0020] According to a preferred form of the first aspect above, Talc powder is Relative to the mass of the polyester resin composition 0.5 Mass%~ 5 mass% That is .

[0021] According to the preferred form of the first viewpoint described above, Acetate powder is, Relative to the mass of the polyester resin composition 0.1 Mass%~ 0.4 mass% That is .

[0022] According to the preferred embodiment of the first viewpoint described above, when a nonwoven fabric that has not been heated to 150°C or higher after fabrication is heated at 180°C for 15 minutes, the unidirectional length shrinkage rate is 10% or less based on the length before heating.

[0023] According to the preferred embodiment of the first viewpoint described above, the degree of crystallinity measured for the polyester resin composition constituting the nonwoven fabric, which has not been heated to 150°C or higher after the nonwoven fabric was manufactured, is 50% or higher.

[0024] According to the preferred form of the first viewpoint described above, The average fiber diameter of the fibers in the nonwoven fabric is between 0.1 μm and 20 μm. .

[0025] According to the preferred embodiment of the third viewpoint described above, the talc powder is, relative to the total mass of the polyester resin and the talc powder, 0.5 Mass%~ 5 This is expressed in mass percent. The acetate powder is, relative to the total mass of the polyester resin and the acetate powder, 0.1 Mass%~ 0.4 It is expressed as mass percent.

[0026] According to the preferred form of the third viewpoint described above, The average fiber diameter of the fibers in the nonwoven fabric is between 0.1 μm and 20 μm. .

[0027] A nonwoven fabric according to the first embodiment of this disclosure will now be described. The nonwoven fabric of this disclosure is a nonwoven fabric composed of fibers of a polyester resin composition. The nonwoven fabric of this disclosure can be, for example, a meltblown nonwoven fabric, a chemical bond nonwoven fabric, a spunbond nonwoven fabric, etc. Of these, a meltblown nonwoven fabric is preferred from the viewpoint of versatility and ease of manufacture.

[0028] The polyester resin composition comprises a first resin. The first resin is a polyester resin that is a copolymer of an acid component (polycarboxylic acid) and an alcohol component (polyol, polyhydroxy compound). In this disclosure, polycarboxylic acid means a compound having multiple carboxyl groups. Polyol or polyhydroxy compound means a compound having multiple hydroxyl groups. In this disclosure, unless otherwise specified, the polyester resin may also include molded articles.

[0029] The acid component mainly consists of terephthalic acid. The terephthalic acid content is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 100 mol% relative to the total amount of acid components. If the terephthalic acid content is less than 90 mol%, the melting point of the polyester resin decreases.

[0030] The acid component may contain other acid components, to the extent that it does not alter the essential properties of the polyester resin of this disclosure. Examples of other acid components include isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, succinic acid, dimer acid, 1,4-cyclohexadicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, trimellitic acid, and derivatives thereof. These other acid components may be included individually or in any proportion of two or more.

[0031] The alcohol component mainly consists of an ethylene glycol component. The ethylene glycol component content is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 100 mol% relative to the total amount of alcohol components. If the ethylene glycol component content is less than 90 mol%, the melting point of the polyester resin decreases.

[0032] The alcohol component may contain other alcohol components, to the extent that it does not alter the essential properties of the polyester resin of this disclosure. Examples of other alcohol components include 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), polyethylene glycol, polytetramethylene glycol, and derivatives thereof. These other alcohol components may be included individually or in any proportion of two or more.

[0033] The first resin may contain a polymerization catalyst.

[0034] The first resin is described later. This disclosure It can be made of polyester resin.

[0035] The first resin is preferably polyethylene terephthalate (PET).

[0036] The first resin is preferably 90% by mass or more, and preferably 95% by mass or more, relative to the mass of the polyester resin composition. twist Preferably, it is 100% by mass. If the first resin is less than 90% by mass, the heat resistance will decrease.

[0037] The polyester resin composition may further contain a second resin in addition to the first resin. The second resin may be, for example, a polyester resin. Examples of the second resin include polybutylene terephthalate.

[0038] The polyester resin composition further comprises powder. The powder corresponds to a crystal nucleating agent, which will be described later. The powder can be at least one selected from the group consisting of talc and acetates. Examples of acetates include sodium acetate and potassium acetate.

[0039] The amount of talc powder is preferably 0.3% by mass or more relative to the mass of the polyester resin composition. For example, the amount of talc powder can be 0.5% by mass or more, 1% by mass or more, 2% by mass or more, or 3% by mass or more, relative to the mass of the polyester resin composition. The amount of talc powder is preferably 7% by mass or less relative to the mass of the polyester resin composition. For example, the amount of talc powder can be 5% by mass or less, or 2% by mass or less, relative to the mass of the polyester resin composition.

[0040] The acetate powder is preferably at least 0.05% by mass relative to the mass of the polyester resin composition. For example, the acetate powder can be at least 0.1% by mass, at least 0.2% by mass, or at least 0.3% by mass relative to the mass of the polyester resin composition. The acetate powder is preferably at least 0.5% by mass relative to the mass of the polyester resin composition. For example, the acetate powder can be at least 0.4% by mass, at least 0.3% by mass, or at least 0.2% by mass relative to the mass of the polyester resin composition.

[0041] The average particle size of the powder is preferably 5 μm or less. If it exceeds 5 μm, it will affect the nonwoven fabric. of This can cause nozzle contamination or clogging during the manufacturing process. The average particle size of the powder can be measured, for example, using a laser diffraction / scattering particle size distribution analyzer.

[0042] The intrinsic viscosity (IV value) of the polyester resin composition is 0.25 dl / g (10 2 cm 3It is preferable that the intrinsic viscosity is 0.45 dl / g or higher. If the intrinsic viscosity is less than 0.25 dl / g, the strength of the nonwoven fabric will decrease, which may cause problems during use. It is preferable that the intrinsic viscosity (IV value) of the polyester resin composition is 0.45 dl / g or less. If the intrinsic viscosity exceeds 0.45 dl / g, the performance as a nonwoven fabric will decrease, such as the heat shrinkage rate increasing.

[0043] The intrinsic viscosity of the polyester resin composition is determined in a mixed solvent of phenol:tetrachloroethane = 60:40 (mass ratio). Polyester resin composition This is the intrinsic viscosity at 20°C, measured using an automatic viscometer equipped with an Ubbelohde viscometer after dissolving 0.5000 ± 0.0005 g.

[0044] The melting point of the polyester resin composition is preferably 250°C or higher. If it is below 250°C, the heat resistance will decrease. The melting point of the polyester resin composition is preferably 260°C or lower. If it exceeds 260°C, the thermal shrinkage rate may increase. The melting point of the polyester resin composition can be determined, for example, using a differential scanning calorimetry (DSC) device. Polyester resin composition It can be measured directly from there.

[0045] The cooling crystallization temperature of the polyester resin composition is preferably 185°C or higher. If it is less than 185°C, heat The shrinkage rate will be high. Preferably, the cooling crystallization temperature of the polyester resin composition is 235°C or lower. If it exceeds 235°C, the resin is more likely to adhere to the nozzle during nonwoven fabric manufacturing, leading to thread breakage and potentially poor appearance of the nonwoven fabric. The cooling crystallization temperature of the polyester resin composition can be determined, for example, using a differential scanning calorimetry (DSC) device. Polyester resin composition It can be measured directly from there.

[0046] The aforementioned cooling crystallization temperature is the exothermic peak associated with crystallization that appears when the material is held above its melting point using a DSC apparatus and then cooled at a rate of 10°C / min.

[0047] The powder can be used in the following methods: blending a masterbatch, which has been pre-mixed to a high concentration in a polyester resin using a kneader or the like, with a first resin to produce a nonwoven fabric; blending the first resin with the powder to produce a nonwoven fabric; or adding the powder to the first resin during its preparation, similar to a polymerization catalyst, and then producing a nonwoven fabric from the resulting first resin. any of Add using this method as well can The preferred method for adding talc is to use a masterbatch. The preferred method for adding acetate is to add it when preparing the first resin.

[0048] The nonwoven fabric disclosed herein, before being subjected to heat treatment above 150°C after manufacturing, is heated at 180°C for 15 minutes. heat It is preferable that the nonwoven fabric has a shrinkage rate of 10% or less. heat The shrinkage rate is preferably 8% or less, and more preferably 6% or less. heat If the shrinkage rate exceeds 10%, problems are more likely to occur during use. heat The shrinkage rate is preferably 10% or less in both the vertical and horizontal directions.

[0049] The heat shrinkage rate of nonwoven fabric is calculated by marking a line on a nonwoven fabric that has not been heat-treated above 150°C after manufacturing, and then heat-treating it at 180°C for 15 minutes, using the following formula. Thermal shrinkage rate (%) = [(L0 - L) / L0] × 100 L0: Length of the mark before heating L: Length of the mark after heating

[0050] It is preferable that the crystallinity of the polyester resin composition constituting the nonwoven fabric, which has not been subjected to heat treatment at 150°C or higher after manufacturing, is 50% or higher. The polyester resin composition in the nonwoven fabric of this disclosure may have a crystallinity of 55% or higher, 60% or higher, 65% or higher, 70% or higher, 75% or higher, or 80% or higher at the stage before heat treatment at 150°C or higher after manufacturing. If the crystallinity of the polyester resin composition is less than 50%, shrinkage is likely to occur in high-temperature environments.

[0051] The degree of crystallinity is determined by using a DSC instrument to analyze the nonwoven fabric under nitrogen. atmosphere During heating, the temperature was increased from 30°C to 300°C at a heating rate of 10°C / min, and the crystallization temperature (Tc), crystallization enthalpy (ΔHc), and melting point (Tm) were determined. and The heat of fusion (ΔHm) can be measured and calculated using the following formula. Crystallinity (%)=((ΔHm−ΔHc) / ΔHm)×100

[0052] The average fiber diameter of the fibers in the nonwoven fabric of this disclosure is preferably 0.1 μm or more, and more preferably 0.3 μm or more. The average fiber diameter of the fibers in the nonwoven fabric of this disclosure can be, for example, 1 μm or more, 2 μm or more, or 3 μm or more. If the average fiber diameter is less than 0.1 μm, the fibers become prone to breaking, and the strength of the nonwoven fabric also decreases. The average fiber diameter of the fibers in the nonwoven fabric of this disclosure is preferably 20 μm or less, and more preferably 15 μm or less. The average fiber diameter of the fibers in the nonwoven fabric of this disclosure can be, for example, 10 μm or less, 6 μm or less, or 5 μm or less. If the average fiber diameter exceeds 20 μm, the pore size of the nonwoven fabric tends to increase, and the performance of the nonwoven fabric (filter performance, etc.) decreases. The fiber diameter of the fibers can be measured with a scanning electron microscope. The average fiber diameter can be, for example, the average value of the fiber diameters of 100 fibers.

[0053] The method for manufacturing the nonwoven fabric described herein will be described later. This disclosure The method for manufacturing nonwoven fabrics according to this disclosure includes a step of preparing polyester resin. This disclosureThis process includes the step of producing polyester nonwoven fabric from polyester resin.

[0054] The method for manufacturing a nonwoven fabric according to the present disclosure includes at least one of the steps of preparing a polyester resin and manufacturing a nonwoven fabric, wherein before manufacturing the nonwoven fabric, This disclosure The process may further include adding talc powder and / or acetate powder to the polyester resin. The timing and amount of talc powder and / or acetate powder to be added should be referred to in accordance with the above description.

[0055] Nonwoven fabric manufacturing The method can be appropriately selected depending on the intended use of the nonwoven fabric. For example, the nonwoven fabric manufacturing One possible method is the meltblown method. When using the meltblown method, it is preferable to set the extrusion temperature within a range that allows the polyester resin to be meltblown while preventing thermal decomposition of the polyester resin. The conditions for the meltblown method can be set, for example, to an extrusion temperature of 260-280°C, a hot air temperature of 230-300°C, a hot air flow rate of 1,600 L / min or more, and a collection distance of 12 cm or less. The hot air temperature can be, for example, 280°C or less. The hot air flow rate can be, for example, 1,800 L / min or more. The hot air flow rate can be, for example, 2,200 L / min or less. The collection distance can be, for example, 10 cm or less. The collection distance can be, for example, 5 cm or more. If the extrusion temperature is below 260°C, the resin will solidify during nonwoven fabric production. If the extrusion temperature exceeds 280°C, the resin will decompose during nonwoven fabric production, resulting in poor strength and texture of the nonwoven fabric. If the hot air temperature is below 230°C, the nozzle cools down, making the resin more likely to solidify during nonwoven fabric production. If the hot air temperature exceeds 300°C, the fibers become more prone to breaking. If the collection distance exceeds 12 cm, the extruded fibers come into contact with the air and cool rapidly, making crystallization difficult. If the hot air flow rate is below 1,600 L / min, the fibers are not stretched, making crystallization difficult.

[0056] The method for manufacturing nonwoven fabrics according to this disclosure preferably does not involve a heat treatment (annealing treatment) in which the manufactured nonwoven fabric is heated to 150°C or higher. This eliminates the need for processes and equipment for heat treatment, thereby reducing manufacturing costs.

[0057] The polyester resin composition in the nonwoven fabric of this disclosure has PET as its main structure. Therefore, the nonwoven fabric of this disclosure has high heat resistance.

[0058] The polyester resin composition in the nonwoven fabric of this disclosure has a high degree of crystallinity. Therefore, shrinkage of the nonwoven fabric is suppressed even when the nonwoven fabric is used in a high-temperature environment.

[0059] Since the nonwoven fabric disclosed herein has PET as its basic structure, it can be manufactured at low cost.

[0060] The nonwoven fabrics disclosed herein can be applied, for example, to filters, sound-absorbing materials, heat-insulating materials, and the like.

[0061] The polyester resin of this disclosure is a resin for manufacturing a nonwoven fabric according to the first embodiment. For example, the polyester resin of this disclosure may be the resin before melting for manufacturing the nonwoven fabric, or the resin in a molten state. The powder according to the first embodiment can act as a crystal nucleating agent to promote the crystallization of the polyester resin after it has melted.

[0062] This disclosure Polyester resins are copolymers of an acid component (polycarboxylic acid) and an alcohol component (polyol, polyhydroxy compound).

[0063] The acid component mainly consists of terephthalic acid. The terephthalic acid content is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 100 mol% relative to the total amount of acid components. If the terephthalic acid content is less than 90 mol%, the melting point of the polyester resin decreases.

[0064] The acid component may contain other acid components, to the extent that it does not alter the essential properties of the polyester resin of this disclosure. Examples of other acid components include isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, adipic acid, sebacic acid, succinic acid, dimer acid, 1,4-cyclohexadicarboxylic acid, dimethyl terephthalate, dimethyl isophthalate, trimellitic acid, and derivatives thereof. These other acid components may be included individually or in any proportion of two or more.

[0065] The alcohol component mainly consists of an ethylene glycol component. The ethylene glycol component content is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 100 mol% relative to the total amount of alcohol components. If the ethylene glycol component content is less than 90 mol%, the melting point of the polyester resin decreases.

[0066] The alcohol component may contain other alcohol components, to the extent that it does not alter the essential properties of the polyester resin of this disclosure. Examples of other alcohol components include 1,3-propanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), polyethylene glycol, polytetramethylene glycol, and derivatives thereof. These other alcohol components may be included individually or in any proportion of two or more.

[0067] This disclosure The polyester resin is preferably polyethylene terephthalate (PET).

[0068] This disclosureThe intrinsic viscosity (IV value) of the polyester resin is preferably 0.3 dl / g or higher. If the intrinsic viscosity is less than 0.3 dl / g, it may be difficult to produce a high-strength nonwoven fabric. This disclosure The intrinsic viscosity (IV value) of the polyester resin is preferably 0.5 dl / g or less. If the intrinsic viscosity exceeds 0.5 dl / g, it becomes difficult to produce nonwoven fabrics with low heat shrinkage.

[0069] The above intrinsic viscosity was measured at 20°C using an automatic viscometer equipped with an Ubbelohde viscometer, after dissolving 0.5000±0.0005g of polyester resin in a mixed solvent of phenol:tetrachloroethane = 60:40 (mass ratio).

[0070] This disclosure The melting point of the polyester resin is preferably 250°C or higher. If it is below 250°C, its heat resistance will decrease. This disclosure The melting point of the polyester resin is preferably 260°C or lower. A melting point exceeding 260°C may result in a higher thermal shrinkage rate. This disclosure The melting point of polyester resin can be measured, for example, using a differential scanning calorimetry (DSC) device.

[0071] This disclosure The cooling crystallization temperature of the polyester resin is preferably 185°C or higher. If it is below 185°C, heat The rate of contraction will increase. This disclosure The cooling crystallization temperature of the polyester resin is preferably 235°C or lower. If it exceeds 235°C, the resin is more likely to adhere to the nozzle during the manufacturing of the nonwoven fabric, which can cause thread breakage and other problems, potentially resulting in a poor appearance of the nonwoven fabric. This disclosure The cooling crystallization temperature of polyester resins can be measured, for example, using a differential scanning calorimetry (DSC) device.

[0072] This disclosureThe polyester resin can be used as a masterbatch for manufacturing the nonwoven fabric according to the first embodiment. When the polyester resin is used as a masterbatch, the amount of the powder acting as a crystal nucleating agent can be 30% by mass or more, 40% by mass or more, or 45% by mass or more, based on the total mass of the polyester resin masterbatch and the powder. The amount of the powder acting as a crystal nucleating agent can be 70% by mass or less, 60% by mass or less, or 55% by mass or less, based on the total mass of the polyester resin masterbatch and the powder.

[0073] This disclosure Polyester resin can be used as a raw material for manufacturing a nonwoven fabric according to the first embodiment.

[0074] This disclosure Polyester resins can be produced by known methods. For example, ester prepolymers may be produced by direct esterification using unsubstituted polycarboxylic acids as starting materials, or by transesterification reactions using esterified products such as dimethyl esters as starting materials. From the viewpoint of production efficiency, direct esterification reactions are preferred.

[0075] Direct esterification reactions can be carried out, for example, by charging the raw materials into a reaction vessel equipped with a heating device, a stirrer, and a distillation tube, raising the temperature while stirring under atmospheric pressure and an inert gas atmosphere, and allowing the reaction to proceed while distilling off the water produced by the reaction. Direct esterification can be carried out at a rate of 0-3 kg / cm³. 2 The reaction can be carried out at 240°C to 270°C under pressure G, preferably at 245°C to 255°C. The reaction time can be, for example, 3 to 7 hours.

[0076] The transesterification reaction can be carried out, for example, by charging the raw materials into a reaction vessel equipped with a heating device, a stirrer, and a distillation tube, adding a reaction catalyst, and raising the temperature while stirring under atmospheric pressure and an inert gas atmosphere, while allowing the reaction to proceed while distilling off the methanol produced by the reaction. The reaction temperature can be, for example, 150°C to 270°C, and is preferably 160°C to 260°C. The reaction time is, for example, about 3 to 7 hours.

[0077] At least one metal compound can be used as a catalyst for the transesterification reaction. Preferred metal elements include, for example, sodium, potassium, calcium, titanium, lithium, magnesium, manganese, zinc, tin, and cobalt. Of these, titanium and manganese compounds are preferred because they are highly reactive and produce a good color tone in the resulting resin. The amount of transesterification catalyst added is usually preferably 5 ppm to 1000 ppm, and more preferably 10 ppm to 100 ppm, relative to the polyester resin produced.

[0078] After the transesterification reaction is complete, it is desirable to add an equimolar or greater amount of phosphorus compound to the transesterification catalyst to further proceed with the transesterification reaction. Examples of phosphorus compounds include phosphoric acid, phosphorous acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trimethyl phosphite, triethyl phosphite, and tributyl phosphite. Of these, trimethyl phosphate is particularly preferred. The amount of phosphorus compound used is preferably 5 ppm to 1000 ppm, and more preferably 20 ppm to 100 ppm, relative to the mass of the polyester resin produced.

[0079] Following a direct esterification or transesterification reaction, a polymerization catalyst is added to the ester prepolymer, and a polycondensation reaction is carried out further until the desired molecular weight is achieved. As the catalyst in the polymerization reaction, for example, tetra-n-butyl titanate can be used. The catalyst addition rate can be, for example, 1 ppm to 10 ppm relative to the amount of resin produced. The polycondensation reaction can be carried out, for example, by gradually increasing the temperature and reducing the pressure inside the reaction vessel after adding the polymerization catalyst. The pressure inside the vessel is preferably reduced to, for example, 0.4 kPa or less, preferably 0.2 kPa or less. The temperature inside the vessel is preferably increased to, for example, 250°C to 290°C. The polymerization reaction can be carried out, for example, under reduced pressure until a predetermined melt viscosity is achieved, with the final internal pressure of the vessel being 150 Pa or less. After that, the internal pressure can be increased to, for example, 0.5 MPa, and the reaction product can be pushed out from the bottom of the vessel and recovered. For example, the reaction product can be extruded into water in a strand shape, cooled, and then cut to obtain a pellet-shaped polyester resin.

[0080] The polymerization catalyst is preferably a titanium compound. Using a titanium compound can increase the cooling crystallization temperature of the polyester resin produced.

[0081] Other catalysts besides titanium compounds can be used as polymerization catalysts. For example, germanium oxide can be used as a polymerization catalyst. When using germanium oxide, the catalyst addition rate can be, for example, 50 ppm to 300 ppm relative to the amount of resin produced.

[0082] The polyester resin of this disclosure may be appropriately blended with various additives such as antioxidants, heat stabilizers, lubricants, antistatic agents, plasticizers, ultraviolet absorbers, and pigments, as long as they do not impair the effects of this disclosure. These additives may be blended in either the polymerization reaction step or the processing / molding step. Examples of antioxidants include hindered phenol antioxidants, phosphorus antioxidants, and sulfur antioxidants, with hindered phenol antioxidants being particularly preferred. The amount added should preferably be around 100 ppm to 5000 ppm.

[0083] This disclosure The intrinsic viscosity (IV value) of polyester resin is 0.3 dl / g (10 2 cm 3 It is preferable that the intrinsic viscosity is 0.5 dl / g or higher. If the intrinsic viscosity is less than 0.3 dl / g, the strength will decrease when the fabric is made into a nonwoven, which may cause problems during the manufacturing and use of the nonwoven. The intrinsic viscosity (IV value) of the polyester resin of this disclosure is preferably 0.5 dl / g or less. If the intrinsic viscosity exceeds 0.5 dl / g, the melt viscosity will increase, requiring molding at high temperatures when manufacturing the nonwoven, resulting in a decrease in strength. Alternatively, the fiber diameter will increase, leading to a larger pore size and higher heat shrinkage rate of the nonwoven, thus reducing the performance of the nonwoven.

[0084] The above intrinsic viscosity was measured at 20°C using an automated viscometer equipped with an Ubbelohde viscometer, after dissolving 0.5000 ± 0.0005 g of the sample in a mixed solvent of phenol:tetrachloroethane = 60:40 (mass ratio).

[0085] The melting point of the polyester resin of this disclosure is preferably 250°C or higher. If it is below 250°C, the melting point is low. Therefore The heat resistance decreases. Preferably, the melting point of the polyester resin of this disclosure is 260°C or lower. If it exceeds 260°C, the molding temperature increases, the degree of crystallinity decreases when it is made into a nonwoven fabric, and in a high-temperature environment... heat The shrinkage rate may be high. The melting point can be measured, for example, using a differential scanning calorimetry (DSC) device.

[0086] This disclosure The cooling crystallization temperature of polyester resin is preferably 185°C or higher. Below 185°C, the crystallization rate of the resin is slow. Therefore When made into nonwoven fabric heatThe shrinkage rate increases. Preferably, the cooling crystallization temperature of the polyester resin of this disclosure is 235°C or lower. If it exceeds 235°C, the resin is more likely to adhere to the nozzle when manufacturing the nonwoven fabric, causing thread breakage and potentially resulting in a poor appearance of the nonwoven fabric. The cooling crystallization temperature can be measured, for example, using a differential scanning calorimetry (DSC) device.

[0087] The polyester resin of this disclosure may contain talc. Preferably, the amount of talc is 0.3% by mass or more relative to the total mass of the polyester resin and powder. If the amount of talc is less than 0.3% by mass, the cooling crystallization temperature will be lower, and the thermal shrinkage rate of the nonwoven fabric will be higher. For example, the amount of talc can be 0.5% by mass or more, 1% by mass or more, 2% by mass or more, or 3% by mass or more relative to the total mass of the polyester resin and powder. Preferably, the amount of talc is 7% by mass or less relative to the total mass of the polyester resin and powder. For example, the amount of talc can be 5% by mass or less, or 2% by mass or less, relative to the total mass of the polyester resin and powder. If the amount of talc exceeds 7% by mass, talc may accumulate in the nozzle of the nonwoven fabric manufacturing apparatus, making it difficult to produce the desired nonwoven fabric.

[0088] The polyester resin of this disclosure may contain an acetate. For example, sodium acetate can be given as an acetate. Preferably, the amount of acetate is 0.05% by mass or more based on the total mass of the polyester resin and powder. For example, the amount of acetate can be 0.1% by mass or more, 0.2% by mass or more, or 0.3% by mass or more based on the total mass of the polyester resin and powder. If the amount of acetate is less than 0.05% by mass, the cooling crystallization temperature will be lower, and the thermal shrinkage rate of the nonwoven fabric will be higher. Preferably, the amount of acetate is 0.5% by mass or less based on the total mass of the polyester resin and powder. For example, the amount of acetate can be 0.4% by mass or less, 0.3% by mass or less, or 0.2% by mass or less based on the total mass of the polyester resin and powder. If the amount of acetate exceeds 0.5% by mass, the polymerization reaction may be inhibited or the durability of the nonwoven fabric may decrease.

[0089] The talc and acetate described above act as nucleating agents to promote crystallization of the polyester resin. The nucleating agent may be added beforehand when preparing the polyester resin, or it may be added after melting and compounding the polyester resin. The amount of nucleating agent relative to the amount of polyester resin can be set to be the same as the amount of the powder described above.

[0090] The polyester resin disclosed herein has PET as its basic structure, has a higher melting point than PBT, and possesses high heat resistance. Furthermore, due to the above-mentioned intrinsic viscosity and cooling crystallization temperature, the polyester resin disclosed herein has a melt viscosity and crystallization rate suitable for the meltblown process. In addition, because it has PET as its basic structure, the polyester resin disclosed herein can be manufactured at low cost.

[0091] The polyester resins and nonwoven fabrics of this disclosure may be impossible or impractical to identify directly by their composition, structure, properties, etc. In such cases, the polyester resins and nonwoven fabrics of this disclosure may be identified by their manufacturing methods.

[0092] The polyester resins of this disclosure are described below. polyester resin composition The polyester resin and nonwoven fabrics made therefrom will be described using examples. polyester resin composition The nonwoven fabrics are not limited to the following examples. [Examples]

[0093] [Test Example 1] -1 ~3 -1 ] stirrer, thermometer, and25.6 kg of terephthalic acid and 11.0 kg of ethylene glycol were charged into a reaction vessel equipped with a distillation tube, and the esterification reaction was carried out at 0.2 MPa and 250°C for 3 hours with stirring. After confirming that no more distillate water was being discharged from the reaction system, the pressure in the reaction system was returned to atmospheric pressure, and the reaction was carried out for an additional hour. Subsequently, the mixed solution of tetrabutyl titanate and ethylene glycol was prepared to a concentration of 10 ppm of Ti, and the mixed solution of triethyl phosphate and ethylene glycol was prepared to a concentration of 20 ppm of P. Yo It was added to [the mixture]. Then, the temperature was gradually increased while the pressure was reduced until the final temperature reached 280°C and the pressure 0.2 hPa. The reaction was continued until the torque value of the stirring blade corresponding to the intrinsic viscosity reached the desired value, and the polycondensation reaction was terminated. The obtained polyester resin was extracted in strand form from the outlet at the bottom of the reaction vessel, cooled in a water bath, and then cut into chips.

[0094] About the polyester resin that was manufactured 、 IV, melting point, and The cooling crystallization temperature was measured. Table 1 shows the composition and measurement results. In Tables 1 and 2, PET is polyethylene terephthalate. It is an abbreviation for PBT stands for polybutylene terephthalate. It is an abbreviation for In the section on polymerization catalysts, Ti is tetrabutyl titanate. meaning Ge is germanium dioxide meaning .

[0095] 1) Intrinsic viscosity (IV) A solution was prepared by dissolving 0.5000±0.0005g of each polyester resin in 50ml of a mixed solvent of 1,1,2,2-tetrachloroethane and phenol (1,1,2,2-tetrachloroethane:phenol = 40:60 (weight ratio)). The viscosity was then determined at 20°C using an automatic viscometer equipped with an Ubbelohde viscometer, based on the ratio of the flow time of the test solution to the flow time of the solvent (flow time of the test solution / flow time of the solvent).

[0096] 2) Melting point and cooling crystallization temperature 10 mg of polyester resin was weighed and isothermally maintained at 300°C for 3 minutes in a nitrogen atmosphere using a differential scanning calorimetry (DSC2500, TA Instruments). After cooling from 300°C to 30°C at a rate of 50°C / min, the endothermic behavior was observed while the temperature was increased from 30°C to 300°C at a rate of 10°C / min, and the melting point was measured. After reaching 300°C, the resin was isothermally maintained at 300°C for 3 minutes, and then cooled from 300°C to 30°C at a rate of 10°C / min. The cooling crystallization temperature was measured from the exothermic behavior.

[0097] [Test Examples 1-2 to 3-2] Using the obtained polyester resin, a meltblown nonwoven fabric was produced using a meltblown nonwoven fabric manufacturing machine (MBT-200, manufactured by Shinwa Kogyo Co., Ltd.) to achieve a basis weight of 50 g / m². 2 A meltblown nonwoven fabric was produced. The extrusion temperature was set to 280°C, the hot air used to blow the fibers was set to 300°C and 2000 L / min, and a nozzle with 401 holes, an inner diameter of 0.2Φ, and a length of 0.8 mm was used.

[0098] Regarding the nonwoven fabric produced, the IV, melting point, and other properties of the polyester resin constituting the nonwoven fabric are determined according to the method described above. and The cooling crystallization temperature was measured. Additionally, the average fiber diameter, heat shrinkage coefficient, and degree of crystallinity of the polyester resin were measured for the prepared nonwoven fabric. The measurement results are shown in Table 2.

[0099] 3) Average fiber diameter of the fiber Using a scanning electron microscope (SU3500, Hitachi High-Technologies Corporation), the diameters of 100 random fibers in the nonwoven fabric were measured, and the average of these 100 diameters was defined as the average fiber diameter.

[0100] 4) Thermal shrinkage rate After preparation, 10 cm long markings were made on the surface of the nonwoven fabric, which had not been heated above 150°C, in both the MD direction (winding direction of the nonwoven fabric) and the TD direction (perpendicular to the vertical direction). The nonwoven fabric was then heated in an oven at 180°C for 15 minutes. by The material was subjected to heat treatment. After heat treatment, the length of the markings was measured. The thermal shrinkage rate was calculated using the following formula. heat The contraction rate was calculated as the average of two measurements in the MD direction and two measurements in the TD direction. Thermal shrinkage rate (%) = [(L0 - L) / L0] × 100 In the formula, L0 is the length of the mark before heating, and L is the length of the mark after heating.

[0101] 5) Degree of crystallinity After preparation, the nonwoven fabric, which has not been heated above 150°C, was subjected to a differential scanning calorimetry (DSC2500, TA Instruments) using nitrogen. atmosphere During heating, the temperature was increased from 30°C to 300°C at a heating rate of 10°C / min, and the crystallization temperature (Tc), crystallization enthalpy (ΔHc), and melting point (Tm) were determined. and The heat of fusion (ΔHm) was measured. (Method for calculating crystallinity) Crystallinity (%)=((ΔHm−ΔHc) / ΔHm)×100

[0102] [Test Example 4] -1 ] The polymerization catalyst was changed to 200 ppm germanium dioxide, as shown in Test Example 1. -1 ~3 -1 Similarly do, A polyester resin was prepared. Test Example 1 of the prepared polyester resin. -1 ~3 -1 In the same way 、 IV, melting point, and The cooling crystallization temperature was measured. Table 1 shows the composition and measurement results.

[0103] [Test Example 4-2] obtained polyester resin Using, Test Example 1 -2 Similarly hand A nonwoven fabric was prepared. Regarding the prepared nonwoven fabric, Test Example 1 -2 ~3 -2 Similarly, the IV, melting point, and cooling crystallization temperature of the polyester resin constituting the nonwoven fabric, as well as the average fiber diameter, heat shrinkage coefficient, and degree of crystallinity of the polyester resin, were measured. The measurement results are shown in Table 2.

[0104] [Test Example 5] -1 ] stirrer, thermometer, and In a reaction vessel equipped with a distillation tube, 26.5 kg of dimethyl terephthalate and 20.1 kg of a 1,4-butanediol mixed solution of 1,4-butanediol and tetrabutyl terephthalate were charged to a concentration of 50 ppm of titanium. Under stirring, the temperature was gradually increased from 150°C, and the transesterification reaction was carried out while distilling off methanol. The reaction finally reached 230°C and took 4 hours. After that, the temperature was gradually increased while the pressure was reduced until the final temperature was 240°C and the pressure was 0.2 hPa. The reaction was continued until the torque value of the stirring blade corresponding to the intrinsic viscosity reached the desired value, and the polycondensation reaction was terminated. The obtained polyester resin was extracted in strand form from the outlet at the bottom of the reaction vessel, cooled in a water bath, and then cut into chips.

[0105] Test Example 1 of the prepared polyester resin -1 ~3 -1 In the same way 、 IV, melting point, and The cooling crystallization temperature was measured. Table 1 shows the composition and measurement results.

[0106] [Test Example 5-2] obtained polyester resin Using, Test Example 1 -2 Similarly hand A nonwoven fabric was prepared. Regarding the prepared nonwoven fabric, Test Example 1 -2 ~3 -2 Similarly, the IV, melting point, and cooling crystallization temperature of the polyester resin constituting the nonwoven fabric, as well as the average fiber diameter, heat shrinkage coefficient, and degree of crystallinity of the polyester resin, were measured. The measurement results are shown in Table 2.

[0107] [Test Example 6] -1 ~11 -1 ] Test Example 1 -1 Similarly do A polyester resin was prepared. Test Example 1 of the prepared polyester resin. -1 ~3 -1 In the same way 、 IV, melting point, andThe cooling crystallization temperature was measured. Table 1 shows the composition and measurement results.

[0108] [Test Examples 6-2 to 11-2] Using the obtained polyester resin 、 A masterbatch containing 50% by weight of talc powder was prepared. The amount of talc added to the masterbatch is shown in Table 2. Yo The prepared polyester resin was then added during the nonwoven fabric production process, and the nonwoven fabric was manufactured. Regarding the manufactured nonwoven fabric, Test Example 1 -2 ~3 -2 Similarly, the temperature IV, melting point, and cooling crystallization temperature of the polyester resin composition constituting the nonwoven fabric, as well as the average fiber diameter, heat shrinkage rate, and degree of crystallinity of the polyester resin composition, were measured. The measurement results are shown in Table 2. Test Example 11 -2 In this case, frequent thread breakage occurred during the production of the nonwoven fabric, making it impossible to obtain the desired nonwoven fabric.

[0109] [Test Example 12] -1 ~17 -1 ] stirrer, thermometer, and 25.6 kg of terephthalic acid and 11.0 kg of ethylene glycol were charged into a reaction vessel equipped with a distillation tube, and sodium acetate powder was added in the amounts shown in Table 1. Yo The mixture was added and the esterification reaction was carried out at 0.2 MPa and 250°C for 3 hours under stirring. After confirming that no more distillate water was being discharged from the reaction system, the pressure in the reaction system was returned to atmospheric pressure and the reaction was carried out for an additional hour. Next, the mixed solution of tetrabutyl titanate and ethylene glycol was prepared to a concentration of 10 ppm of Ti, and the mixed solution of triethyl phosphate and ethylene glycol was prepared to a concentration of 20 ppm of P. Yo It was added to [the substance]. Then, the temperature was gradually increased while the pressure was reduced until the final temperature reached 280°C and the pressure 0.2 hPa. The reaction was continued until the torque value of the stirring blade corresponding to the intrinsic viscosity reached the desired value, and the polycondensation reaction was terminated. The obtained polyester resin was extracted in strand form from the outlet at the bottom of the reaction vessel, cooled in a water bath, and then cut into chips. Test Example 17 -1 In this case, polymerization reaction did not proceed, resulting in cutting defects. Therefore , pellets are collected can There wasn't any. Excess sodium acetate. powder This is thought to be due to a decrease in polymerization reactivity.

[0110] Test Example 1 of the prepared polyester resin -1 ~3 -1 In the same way 、 IV, melting point, and The cooling crystallization temperature was measured. Table 1 shows the composition and measurement results.

[0111] [Test Examples 12-2 to 17-2] obtained polyester resin Using the composition, Test Example 1 -2 Similarly hand A nonwoven fabric was prepared. Regarding the prepared nonwoven fabric, Test Example 1 -2 ~3 -2 Similarly, the temperature index (IV), melting point, and cooling crystallization temperature of the polyester resin composition constituting the nonwoven fabric, as well as the average fiber diameter, heat shrinkage coefficient, and degree of crystallinity of the polyester resin composition, were measured. The measurement results are shown in Table 2.

[0112] Tables 1 and 2 are shown below. Yo In the case of nonwoven fabrics made using a resin having an intrinsic viscosity of 0.3 to 0.5 dl / g and a cooling crystallization temperature of 185°C to 235°C, the results are shown in Test Example 5. -2 PBT Nonwoven fabric made using It was found to have equivalent thermal shrinkage properties. Test Example 8 used a resin that satisfies the cooling crystallization temperature of 185°C to 235°C but has an intrinsic viscosity of 0.65 dl / g. -2 , and Test Example 14 -2 Regarding this, the melt viscosity is high when manufacturing nonwoven fabrics, and excessive residual strain remains when it is turned into yarn. heat This is thought to be due to increased shrinkage. Test Example 1: Nonwoven fabric was prepared using a polyester resin with a cooling crystallization temperature of less than 185°C without the addition of a crystal nucleating agent. -2 ~4 -2 In this case, the thermal shrinkage rate of the nonwoven fabric increased, and the degree of crystallinity of the polyester resin constituting the nonwoven fabric also decreased.

[0113] [Table 1]

[0114] [Table 2]

[0115] The nonwoven fabric and its manufacturing method, as well as the polyester resin of the present invention, have been described based on the above embodiments and examples, but are not limited to the above embodiments and examples. Within the scope of the present invention and based on the fundamental technical concept of the present invention, various modifications, changes, and improvements can be made to each disclosed element (including the elements described in the claims, specification, and drawings). Furthermore, within the scope of the claims of the present invention, a variety of combinations, substitutions, or selections of each disclosed element are possible.

[0116] Further issues, objectives, and embodiments (including modifications) of the present invention are also evident from the entire disclosure of the present invention, including the claims.

[0117] Regarding the numerical ranges described in this book, unless otherwise stated, it should be interpreted that any numerical value or range included within those ranges is specifically described in this book.

[0118] Some or all of the above embodiments may also be described as follows, but are not limited to the following description. the below described The appendix may also be combined with each claim described in the patent claims. [Note 1] It is a polymer of an acid component containing 90 mol% or more of terephthalic acid and an alcohol component containing 90 mol% or more of ethylene glycol. Polyester resins that satisfy the following a) to c): a) It has an intrinsic viscosity of 0.30 dl / g to 0.50 dl / g; b) Having a melting point of 250°C to 260°C; c) Cooling crystallization temperature at 185℃~235℃ to have do.

[0119] Polyester resins disclosed herein composition and polyester Nonwoven fabrics have excellent moldability and heat resistance. Therefore, the polyester resin of this disclosure composition and polyester Nonwoven fabrics can be used in a wide range of applications, such as filters, sound-absorbing materials, and heat-insulating materials.

Claims

1. It is a nonwoven fabric made of polyester resin fibers, The polyester resin composition comprises 90% by mass or more of a first resin relative to the mass of the polyester resin composition, and talc powder and / or acetate powder. The first resin is a polymer of an acid component and an alcohol component, The aforementioned acidic component contains 90 mol% or more of terephthalic acid relative to the total amount of acidic components. The aforementioned alcohol component contains 90 mol% or more of ethylene glycol component relative to the total amount of alcohol component. The talc powder is present in an amount of 0.3% to 7% by mass relative to the mass of the polyester resin composition. The acetate powder is present in an amount of 0.05% to 0.5% by mass relative to the mass of the polyester resin composition. The aforementioned nonwoven fabric is a meltblown nonwoven fabric. The polyester resin composition constituting the nonwoven fabric is a polyester nonwoven fabric that satisfies the following 1) to 3). 1) Having an intrinsic viscosity of 0.25 dl / g to 0.45 dl / g; 2) Having a melting point of 250°C to 260°C; 3) It has a cooling crystallization temperature of 185°C to 235°C.

2. The polyester nonwoven fabric according to claim 1, wherein the talc powder is 0.5% to 5% by mass relative to the mass of the polyester resin composition.

3. The polyester nonwoven fabric according to claim 1 or 2, wherein the acetate powder is 0.1% to 0.4% by mass relative to the mass of the polyester resin composition.

4. When a nonwoven fabric that has not been heated to 150°C or higher after manufacturing is heated to 180°C for 15 minutes, the unidirectional length shrinkage rate is 10% or less, relative to the length before heating. A polyester nonwoven fabric according to any one of claims 1 to 3.

5. The polyester nonwoven fabric according to claim 4, wherein the degree of crystallinity measured for the polyester resin composition constituting the nonwoven fabric, which has not been heated to 150°C or higher after the nonwoven fabric was manufactured, is 50% or higher.

6. The polyester nonwoven fabric according to any one of claims 1 to 5, wherein the average fiber diameter of the fibers in the nonwoven fabric is 0.1 μm or more and 20 μm or less.

7. A polyester resin composition for manufacturing nonwoven fabrics, The polyester resin composition comprises 90% by mass or more of a first resin and talc powder and / or acetate powder. The first resin is a polymer of an acid component and an alcohol component, The aforementioned acidic component contains 90 mol% or more of terephthalic acid relative to the total amount of acidic components. The aforementioned alcohol component contains 90 mol% or more of ethylene glycol component relative to the total amount of alcohol component. The talc powder is present in an amount of 0.3% to 7% by mass relative to the mass of the polyester resin composition. The acetate powder is present in an amount of 0.05% to 0.5% by mass relative to the mass of the polyester resin composition. The aforementioned nonwoven fabric is a meltblown nonwoven fabric. Polyester resin compositions that satisfy the following a) to c): a) Having an intrinsic viscosity of 0.30 dl / g to 0.50 dl / g; b) Having a melting point of 250°C to 260°C; c) It has a cooling crystallization temperature of 185°C to 235°C.

8. A preparation step of adding talc powder and / or acetate powder to a polyester resin to prepare a polyester resin composition that satisfies the following a) to c), The process includes a nonwoven fabric manufacturing step of producing a polyester nonwoven fabric from the polyester resin composition, The talc powder is present in an amount of 0.3% to 7% by mass relative to the total mass of the polyester resin and the talc powder. The amount of the acetate powder is 0.05% to 0.5% by mass relative to the total mass of the polyester resin and the acetate powder. The aforementioned polyester nonwoven fabric is a meltblown nonwoven fabric. A method for producing polyester nonwoven fabric, which does not include a heating step of heating the nonwoven fabric at a temperature of 150°C or higher: a) Having an intrinsic viscosity of 0.30 dl / g to 0.50 dl / g; b) Having a melting point of 250°C to 260°C; c) It has a cooling crystallization temperature of 185°C to 235°C.

9. The talc powder is present in an amount of 0.5% to 5% by mass relative to the total mass of the polyester resin and the talc powder. The method for producing a polyester nonwoven fabric according to claim 8, wherein the amount of acetate powder is 0.1% to 0.4% by mass relative to the total mass of the polyester resin and the acetate powder.

10. The method for producing a polyester nonwoven fabric according to claim 8 or 9, wherein the average fiber diameter of the fibers in the polyester nonwoven fabric is 0.1 μm or more and 20 μm or less.

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