KR20240046863A - Spunbond nonwoven fabric and separator containing it - Google Patents

Abstract

The object of the present invention is to provide a spunbond nonwoven fabric for use as a separation membrane support such as a reverse osmosis membrane, which does not cause bleeding or membrane peeling during membrane forming process, and has dimensional stability and mechanical strength. The present invention is a spunbond nonwoven fabric comprising a core sheath-type composite fiber containing polyester as a core component and a copolymerized polyester as a sheath component, and the melting point of the sheath component is [(melting point of core component) -45]°C or higher [( The melting point of the core component is -15]°C or lower, and the copolymerization component of the cis component is polyethylene glycol in a copolymerization amount of 2% to 15% by mass or/and a copolymerization amount of 2.5 mol% to 7.5 mol% based on the total acid component. It is an isophthalic acid component containing a metal sulfonate group, and the contact angle with water on the surface of the spunbond nonwoven fabric is 0° or more and 80° or less.

Description

Spunbond nonwoven fabric and separator containing it

The present invention is a spunbond nonwoven fabric that achieves both suppression of membrane peeling and mechanical strength when forming a filtration membrane used in water treatment, and is suitable for a support for a filtration membrane.

Nonwoven fabrics are sheet-shaped fabrics in which fibers are intertwined without weaving, and are broadly classified into spunbond nonwoven fabrics, dry staple fiber nonwoven fabrics, and paper-based nonwoven fabrics, depending on the differences in raw materials, web formation methods, and sheeting methods. Among non-woven fabrics, spunbond non-woven fabric is made from long fibers and is obtained through integrated processing from spinning to winding of the non-woven fabric, so it is excellent in productivity and processability and is used in a wide range of fields such as sanitary materials, civil engineering and construction materials, and industrial materials. is unfolding. In particular, it is suitably used for water treatment purposes as a living material.

As a general water treatment method, impurities are removed from water using a filtration membrane having pores. For example, microfiltration membranes and ultrafiltration membranes are used for water treatment at water purification plants, and reverse osmosis membranes are used for seawater desalination.

Since filtration membranes used in water treatment are sometimes used under high pressure, non-woven fabric is used as a separation membrane support from the viewpoint of supplementing strength.

The film forming method of a filtration membrane (separation membrane) used in water treatment involves forming a film by softening a polymer solution containing a separation membrane forming component on a support. Therefore, the nonwoven fabric used as a support is required to be free from film unevenness or pinhole defects due to backing due to over-permeation of the film forming solution, peeling of film components, fluffing, etc., and for this purpose, excellent weight uniformity per unit area is required. Examples of challenges include stability, membrane adhesion, and surface smoothness.

Additionally, in the case of a reverse osmosis membrane support that is often used under high pressure, high mechanical strength, dimensional stability, and membrane peel strength that can withstand high pressure are required. Here, the membrane peeling strength refers to the degree to which mechanical strength is provided to the separator support having membrane adhesiveness to prevent the separator from easily peeling off. Additionally, membrane adhesion indicates whether the permeability of the separation membrane forming component into the separation membrane support is good or bad.

Additionally, in order to improve filtration performance, the separation membrane is used as a separation element unit having a structure in which several layers are laminated rather than a single layer. Since the improvement in filtration performance is proportional to the number of layers of the separation membrane in the separation element unit, thinning the separation membrane support is also exemplified as an issue.

Conventionally, a paper-based nonwoven fabric with excellent rigidity has been proposed to suppress curvature of the support when coating a separator forming component (see Patent Document 1). In addition, it is a separator support with small warpage during film forming processing and excellent dimensional stability, which includes composite fibers in which a low-melting point polymer is arranged around a high-melting point polymer, and the low-melting point polymers are bonded to each other by heat compression during production. A spunbond nonwoven fabric has been proposed (see Patent Document 2). On the other hand, as an environmentally conscious separation membrane support, a spunbond nonwoven fabric containing composite fibers using raw materials derived from biomass resources has been proposed (see Patent Document 3). Additionally, as a separator support with low fluff generation and excellent dimensional stability and durability, a tricot fabric comprising a core sheath-type composite fiber in which a low-melting point polymer is arranged around a high-melting point polymer has been proposed (see Patent Document 4). . In addition, a spunbond nonwoven fabric has been proposed that has high breathability and rigidity, and is flexible and has excellent tactile feel (see Patent Document 5). In addition, a paper-based nonwoven fabric with excellent fabric quality and strength that can handle high pressure conditions when used as a separation membrane for seawater desalination or a separation membrane support for concentration concentration, etc. has been proposed (see Patent Document 6). In addition, thermoplastic nonwoven fabrics with excellent water absorption and water retention properties have been proposed as materials for sanitary materials and materials related to general living (see Patent Document 7).

Japanese Patent Publication No. 2012-67409 Japanese Patent Publication No. 2016-29221 Japanese Patent Publication No. 2018-138704 International Publication No. 2018/147251 International Publication No. 2019/146660 Japanese Patent Publication No. 2010-194478 Japanese Patent Publication No. 2006-299424

The technology described in Patent Documents 1 and 6 uses single fibers cut to a fiber length of 5 mm as binder fibers that thermally bond to the main fibers in the construction of the paper-based nonwoven fabric, so the generation of fluff increases and the mechanical strength decreases. It has the problem of poor weight uniformity and surface smoothness per unit area.

In addition, the technology described in Patent Documents 2 and 3 is a spunbond nonwoven fabric using core-sheath composite fibers with polyethylene terephthalate as the sheath portion, which contains no copolymerization components other than melting point control, and has low affinity with the separator and permeability of the separator. It has the problem that it becomes insufficient, the adhesiveness decreases, and peeling of the separator easily occurs.

The technology described in Patent Document 4 is a tricot fabric using a core sheath type composite fiber with a low melting point polyester 20 to 35°C lower than the melting point of the core portion as the sheath portion, and it is difficult to use it as a separator support of a certain thickness or less. Additionally, when a separator is formed on a tricot fabric, the permeability of the separator into the support becomes insufficient, adhesion decreases, and peeling of the separator easily occurs.

The technology described in Patent Document 5 is a spunbond nonwoven fabric composed of single-component fibers containing a polyester resin copolymerized with polyethylene glycol, and has the problem of low mechanical strength as a separator support that requires use under high pressure.

The technology described in Patent Document 7 is a nonwoven fabric composed of absorbent fibers containing a thermoplastic absorbent resin copolymerized with polyethylene glycol, and when used as a separation membrane support due to poor uniformity in weight per unit area, backing or bleeding due to overpermeation of the membrane forming solution. It has the problem of low mechanical strength.

Therefore, the present invention aims to provide a separator support such as a reverse osmosis membrane that uses a spunbond nonwoven fabric with adjustable mechanical strength and sheet thickness, has excellent adhesion to the separator, and prevents separation of the separator during film formation. did.

The present invention seeks to solve the above problems, and according to the present invention, the following invention is provided.

[1] It is a spunbond nonwoven fabric containing core sheath-type composite fibers in which the core component is polyester and the sheath component is copolyester,

The melting point of the cis component is [(melting point of core component) -45]°C or more and [(melting point of core component)-15]°C or less,

The copolymerization component of the cis component is

Polyethylene glycol with a copolymerization amount of 2% by mass or more and 15% by mass or less,

or/and

It is an isophthalic acid component containing a metal sulfonate group in a copolymerization amount of 2.5 mol% to 7.5 mol% based on the total acid component,

The contact angle with water on the surface of the spunbond nonwoven fabric is 0° or more and 80° or less,

Spunbond nonwoven fabric.

[2] The spun as described in [1] above, wherein the cis component is a copolymerized polyester obtained by copolymerizing 2% by mass or more and 15% by mass or less of polyethylene glycol, and the contact angle with water on the surface of the spunbond nonwoven fabric is 5° or more and 80° or less. Bonded non-woven fabric.

[3] The spunbond nonwoven fabric according to the above [1] or [2], wherein the polyethylene glycol molecular weight of the cis component is 1000 to 35000.

[4] The spunbonded nonwoven fabric according to the above [1] to [3], wherein the arithmetic average roughness of the surface of the spunbonded nonwoven fabric is 0.1 ㎛ or more and 10 ㎛ or less.

[5] The spunbond nonwoven fabric according to the above [1] to [4], wherein the composite mass ratio of the core component and the sheath component of the core sheath type composite fiber is 95:5 to 50:50.

[6] The cis component is a copolymerized polyester copolymerized with an isophthalic acid component containing a metal sulfonate group in an amount of 2.5 mol% or more and 7.5 mol% or less relative to the total acid component, and the contact angle with water on the surface of the spunbond nonwoven fabric is 0° or more. A spunbond nonwoven fabric as described in [1] above, which is smaller than 70°.

[7] The spunbonded nonwoven fabric according to [1] or [6], wherein the spunbonded nonwoven fabric has a density of 0.5 g/cm3 to 1.8 g/cm3.

[8] The spunbond nonwoven fabric according to [6] or [7] above, wherein the composite mass ratio of the core component and the sheath component of the core sheath type composite fiber is 90:10 to 60:40.

[9] A separator comprising the spunbond nonwoven fabric according to any of [1] to [8] above and a polymer component as a component,

The polymer component is at least one selected from the group consisting of polysulfone, polyether sulfone, polyaryl ether sulfone, polyimide, polyvinylidene fluoride, and cellulose acetate, and the penetration rate of the polymer component into the spunbond nonwoven fabric is 5%. Separator, not more than 70%.

According to the present invention, by using a spunbond nonwoven fabric with a small contact angle with water, the permeability of the separator forming component is improved, high membrane peeling strength is obtained, and a separator support that prevents membrane peeling during film formation is obtained. .

[Core sheath type composite fiber]

The core component of the core sheath type composite fiber included in the spunbond nonwoven fabric of the present invention is polyester, polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, and polybutylene succinate. and the like, and also include copolymers thereof. Polyethylene terephthalate and polybutylene terephthalate are preferably used because they have excellent strength.

The sheath component of the core sheath type composite fiber in the present invention is copolymerized with 2% by mass or more and 15% by mass or less of polyethylene glycol, or/and isophthalic acid component containing a metal sulfonate group in an amount of 2.5 mol% to 7.5 mol% based on the total acid components. It is a copolymerized polyester copolymerized by mol%, and when polycondensation reaction is carried out between dicarboxylic acid and/or its ester-forming derivative and alkylene glycol, polyethylene glycol, metal sulfonate group-containing isophthalic acid and/or its ester-forming derivative It is a copolymerization of .

Examples of the dicarboxylic acid and/or its ester-forming derivative include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, and phthalic acid, aliphatic dicarboxylic acids such as adipic acid and sebacic acid, and alicyclic acids such as cyclohexanecarboxylic acid. It is preferable to use group dicarboxylic acids, etc. Additionally, the alkylene glycol is preferably selected from 1,4-butanediol, 1,3-propanediol, ethylene glycol, or a combination thereof.

The copolymerization amount of polyethylene glycol, which is a copolymerization component of the sheath component of the core sheath type composite fiber in the present invention, is 2% by mass or more and 15% by mass or less with respect to the copolyester. The amount of copolymerization is preferably 4% by mass or more, more preferably 8% by mass or more, so that the permeability of the separation membrane forming component can be improved. On the other hand, by setting the copolymerization amount to preferably 14% by mass or less, thread breakage due to tension during spinning can be suppressed, and further, the strength of the spunbond nonwoven fabric can be increased.

By keeping the copolymerization amount of polyethylene glycol within the above range, hydrophilicity improves and the contact angle of the spunbond nonwoven fabric with respect to water decreases. As a result, permeability with the separation membrane forming component is improved. As the hydrophilicity of the non-woven fabric surface improves, the polymer components that make up the separator quickly penetrate into the non-woven fabric, and the adhesion between the non-woven fabric and the separator becomes stronger.

In addition, the amount of polyethylene glycol copolymerization in the spunbond nonwoven fabric and the amount of copolymerization of polyethylene glycol in the sheath component of the core sheath type composite fiber contained in the spunbond nonwoven fabric can be measured and calculated using a nuclear magnetic resonance (NMR) device. there is. Specifically, it is as follows.

(1) 50 mg of measurement sample is taken from the spunbond nonwoven fabric and dissolved in 1 mL of deuterated hexafluoroisopropanol (HFIP).

(2) As a measuring device, for example, “AL-400” manufactured by Nippon Electronics Co., Ltd. is used, and as measuring conditions, NMR measurement is performed at ¹ H-NMR and 128 integration times.

(3) The amount of polyethylene glycol copolymerization (% by mass) in the spunbond nonwoven fabric is calculated from the integral value of the CH ₂ peak in polyethylene glycol obtained from NMR measurement and the integral value of (H) of the benzene ring in the polyethylene terephthalate structure. .

(4) A measurement sample is again taken from the spunbond nonwoven fabric, treated with alkali, and the sheath component is eluted to produce a yarn containing only the core component.

(5) 50 mg of the sample obtained in (4) is dissolved in 1 mL of deuterated hexafluoroisopropanol (HFIP).

(6) NMR measurement was performed similarly to (2) and (3), and the amount of polyethylene glycol copolymerization in the core component was determined based on the integral value of the CH ₂ peak in polyethylene glycol and the integral value of (H) of the benzene ring in the polyethylene terephthalate structure. Calculate (mass%).

(7) Calculated by subtracting the amount of polyethylene glycol copolymerization (% by mass) in the core component from the amount (% by mass) of polyethylene glycol in the spunbond nonwoven fabric and dividing by the cis ratio. Additionally, the sheath ratio is calculated by observing the yarn cross section of the spunbond nonwoven fabric.

The molecular weight of polyethylene glycol, which is a copolymerization component of the sheath component of the core sheath type composite fiber in the present invention, is preferably 1,000 or more and 35,000 or less in terms of number average molecular weight. The number average molecular weight of polyethylene glycol is set to 1000 or more, more preferably 3000 or more, further preferably 4000 or more, and particularly preferably 7000 or more. As a result, the hydrophilicity of the nonwoven fabric can be improved, the permeability with the separator forming component can be improved, and the adhesion between the nonwoven fabric and the separator is improved. On the other hand, by setting the number average molecular weight to 35,000 or less, more preferably 20,000 or less, a decrease in reactivity during copolymerization can be suppressed, and when a nonwoven fabric is used as a separator support, elution of the internal material of the support into water can be suppressed. . In addition, thread breakage due to the posture during spinning can be suppressed, and further, the strength of the spunbond nonwoven fabric can be increased.

In addition, the number average molecular weight of polyethylene glycol in the sheath component of the core sheath type composite fiber contained in the spunbond nonwoven fabric can be measured and calculated by using gel permeation chromatography (GPC). Specifically, as a measuring device, for example, “Differential Refractive Index Detector 2410” manufactured by Waters, etc. is used, and measurement conditions are as follows. That is, 50 mg of the measurement sample is collected in a sealable vial, 1 mL of 28 mass% ammonia water is added, and the sample is dissolved by heating at 120°C for 5 hours. After leaving to cool, add 1.5 mL of 6 mol/L hydrochloric acid and dilute to 5 mL with purified water. After centrifugation, it is filtered through a 0.45㎛ filter, and the filtrate can be analyzed by GPC. The number average molecular weight of polyethylene glycol can be calculated using a molecular weight calibration curve created using known molecular weight standard data.

The metal sulfonate group-containing isophthalic acid component of the sheath component of the core sheath type composite fiber in the present invention includes sodium 4-sulfoisophthalate, potassium 4-sulfoisophthalate, and sodium 5-sulfoisophthalate. , 5-sulfoisophthalate potassium salt, 5-sulfoisophthalate barium salt, etc. Among them, 5-sulfoisophthalate sodium salt and 5-sulfoisophthalate potassium salt are preferable, and 5-sulfoisophthalate sodium salt is especially preferable because of their excellent polycondensation properties. In addition, these metal sulfonate group-containing isophthalic acid components may be of one type of chemical structure, or may be used of a combination of two or more types.

Examples of the above-mentioned ester-forming derivatives of isophthalic acid containing a metal sulfonate group include alkyl esters such as methyl ester and ethyl ester, acid halides such as acid chloride and acid bromide, and isophthalic anhydride. For example, because of excellent polycondensation reactivity, alkyl esters such as methyl ester and ethyl ester are preferable, and methyl ester is especially preferable.

Additionally, the copolymerization amount of the isophthalic acid component containing a metal sulfonate group in the sheath component of the core sheath type composite fiber in the present invention is 2.5 mol% or more and 7.5 mol% or less with respect to the total acid component. Permeability with the separation membrane forming component can be improved by setting it to 2.5 mol% or more, preferably 3.0 mol% or more, relative to the total acid component. On the other hand, by setting the copolymerization amount to 7.5 mol% or less, preferably 7.0 mol% or less, based on the total acid component, yarn breakage due to an increase in the extensional viscosity of the cis component during spinning can be suppressed, and further, spunbond nonwoven fabric. The intensity can be increased.

By setting the isophthalic acid component containing a metal sulfonate group within the above range, hydrophilicity improves and the contact angle of the spunbond nonwoven fabric with respect to water decreases. As a result, the polymer solution constituting the separator quickly penetrates into the nonwoven fabric, the adhesion between the nonwoven fabric and the separator is strengthened, and a spunbond nonwoven fabric excellent as a separator support can be obtained.

In addition, the amount of isophthalic acid component containing a metal sulfonate group in the spunbond nonwoven fabric and the amount of isophthalic acid component containing a metal sulfonate group in the sheath component of the core sheath type composite fiber constituting the spunbond nonwoven fabric were determined using a nuclear magnetic resonance (NMR) device. It can be measured and calculated by using it. Specifically, it is as follows.

(1) 50 mg of measurement sample is taken from the spunbond nonwoven fabric and dissolved in 1 mL of deuterated hexafluoroisopropanol (HFIP).

(2) As a measuring device, for example, “AL-400” manufactured by Nippon Electronics Co., Ltd. is used, and as measuring conditions, NMR measurement is performed under ¹³ C-NMR and 128 integration times.

(3) The amount of isophthalic acid component containing a metal sulfonate group in the spunbond nonwoven fabric based on the integrated value of the carbon (C) peak bonded to the sulfonate group obtained from NMR measurement and the integrated value of carbon (C) in the polyethylene terephthalate structure. Calculate .

(4) A measurement sample is again taken from the spunbond nonwoven fabric, treated with alkali, and the sheath component is eluted to produce a yarn containing only the core component.

(5) 50 mg of the sample obtained in (4) is dissolved in 1 mL of deuterated hexafluoroisopropanol (HFIP).

(6) NMR measurement was performed similarly to (2) and (3), and the spunbond nonwoven fabric was measured based on the integrated value of the carbon (C) peak bonded to the sulfonate group and the integrated value of carbon (C) in the polyethylene terephthalate structure. Calculate the amount of isophthalic acid component containing a metal sulfonate group.

(7) Calculated by subtracting the amount of the isophthalic acid component containing a metal sulfonate group in the core component from the amount of the isophthalic acid component containing a metal sulfonate group in the spunbond nonwoven fabric and dividing by the cis ratio. Additionally, the sheath ratio is calculated by observing the yarn cross section of the spunbond nonwoven fabric.

The fibers constituting the spunbond nonwoven fabric of the present invention may be so-called mixed fibers that are a mixture of multiple types of fibers.

The core component and sheath component of the core sheath type composite fiber contained in the spunbond nonwoven fabric of the present invention reduce friction with contact objects such as various guides and rollers in the nonwoven fabric manufacturing process and improve process passability and color tone of the product. For the purpose of adjusting or improving thermal conductivity and adhesion in the process of thermocompression bonding the spunbond nonwoven fabric, titanium dioxide (TiO ₂ ) particles may be included. Titanium dioxide particles are manufactured by various wet and dry methods, and if necessary, are subjected to pretreatment such as grinding and classification, and then added to the reaction system of copolyester. The addition of particles to the copolyester reaction system may be at any stage, but addition after substantially completing the esterification reaction or transesterification reaction is preferable because the dispersibility in the polymer improves. The amount of particles added to the polymer and the particle size can be changed depending on the application, but the coarse particles are 0.01% to 10% by mass with respect to the copolyester, the average particle size is 0.05㎛ to 5㎛, and the particle size is 4㎛ or more. If it is in the range of 0.4 mg/unit or less, process passability, color tone, and thermal conductivity become particularly good, so it is preferable.

The composite form of the core sheath type composite fiber includes a concentric core sheath type and an eccentric core sheath type since thermal bonding points between fibers can be efficiently obtained as a nonwoven fabric. In addition, the cross-sectional shape of the fiber includes a circular cross-section, a flat cross-section, a polygonal cross-section, a multi-lobed cross-section, and a hollow cross-section.

When the composite form is a concentric core sheath type, the cross-sectional shape of the fiber is preferably a circular cross-section or a flat cross-section, and the adhesion of the fibers by heat compression can be strengthened, and further thinning of the nonwoven fabric can be achieved. By thinning the nonwoven fabric, the number of stacks of separation membranes per separation element unit can be increased, and filtration performance can be improved. By using core sheath-type composite fibers, the fibers in the non-woven fabric can be firmly bonded to each other by heat compression during non-woven fabric production, and compared to the mixed fiber type that mixes fibers made only of high-melting point polymers and fibers made only of low-melting point polymers, , a nonwoven fabric with little variation in the adhesive point on the sheet and a uniform weight per unit area is obtained.

The core component constituting the core sheath type composite fiber is a high melting point polymer, and the sheath component is a low melting point polymer, and the melting point difference is 15°C to 45°C. That is, the melting point of the cis component is [(melting point of core component) -45]°C or more and [(melting point of core component)-15]°C or less. The melting point difference is 15°C or more (i.e., the melting point of the cis component is [(melting point of the core component)-15]°C or less, the same applies hereinafter), preferably 20°C or more (the melting point of the cis component is [(melting point of the core component)-15]°C or less), preferably 20°C or more (i.e., the melting point of the cis component is [(melting point of the core component)-15]°C or less) 20]°C or lower), only the low-melting point polymer of the cis component can be bonded in the thermocompression bonding process, and the strength of the high-melting point polymer disposed in the core portion can be maintained. This can improve the mechanical strength of the nonwoven fabric. In addition, the weight per unit area of the nonwoven fabric can be controlled by thermocompression, the permeability with the separator forming component can be improved, and the adhesion with the separator can be improved. In addition, by combining improved adhesion and mechanical strength, the peel strength of the separator can be improved, the generation of fluff on the surface of the nonwoven fabric can be suppressed, and surface smoothness and dimensional stability can also be improved. Additionally, since the thickness of the nonwoven fabric is also suppressed, the number of separation membrane layers per separation element unit can be increased, and filtration performance can be improved.

On the other hand, the melting point difference is 45°C or lower (the melting point of the cis component is [(melting point of the core component) -45]°C or higher), preferably 40°C or lower (the melting point of the cis component is [(melting point of the core component) -40]°C). By doing the above), excessive adhesion of the low melting point polymer of the cis component can be suppressed during heat compression. As a result, the weight per unit area of the nonwoven fabric can be controlled and a decrease in the permeability of the separator forming component into the nonwoven fabric is suppressed. Suppression of a decrease in the permeability of the separator forming component can suppress a decrease in the peel strength of the separator in order to improve the adhesion between the nonwoven fabric and the separator. In addition, even when producing a nonwoven fabric, the melting point difference with the high melting point polymer of the core component can be reduced, so decomposition of the low melting point polymer of the sheath component during spinning can be suppressed, and yarn breakage can be suppressed. You can. As a result, the mechanical strength of the nonwoven fabric can be improved, the generation of fluff can be suppressed, and surface smoothness can also be improved.

The melting point difference can be controlled to a desired range by the amount of polymer copolymerization. As the melting point control substance in the low melting point polymer of the cis component, a dicarboxylic acid component is preferable in consideration of copolymerization into polyester, and includes isophthalic acid, cyclohexane dicarboxylic acid, naphthalenedicarboxylic acid, and adipic acid. , sebacic acid is more preferable, and isophthalic acid, which has good polymerizability during copolymerization, is even more preferable. It is preferable that these dicarboxylic acid components are 5 mol% or more and 25 mol% or less relative to the total acid components from the viewpoint of controlling the melting point. The dicarboxylic acid component is preferably 5 mol% or more, more preferably 8 mol% or more, and even more preferably 11 mol% or more. On the other hand, by setting the dicarboxylic acid component to 25 mol% or less, more preferably 22 mol% or less, the melting point difference between the high melting point polymer and the low melting point polymer can be controlled to a desired range.

The melting point of the high melting point polymer of the core component is preferably 160°C to 320°C when using the spunbond nonwoven fabric of the present invention as a separation membrane support from the viewpoint of obtaining a separation membrane with good film forming properties and excellent durability. The melting point of the high-melting point polymer is more preferably 170°C or higher, and even more preferably 180°C or higher, so that the mechanical strength and dimensional stability are excellent even after passing through the heating process when manufacturing the separation membrane or separation element unit. On the other hand, the melting point of the high melting point polymer is more preferably 300°C or lower, and still more preferably 280°C or lower, so that the spinning temperature can be suppressed and decomposition of the polymer can be suppressed. By suppressing decomposition of the polymer, thread breakage during spinning can be reduced, and the mechanical strength of the nonwoven fabric can be obtained.

In addition, the method for measuring and calculating the melting points of the core component and sheath component from the spunbond nonwoven fabric is the following method.

(1) 5 mg of a measurement sample is taken from the spunbond nonwoven fabric, and as 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, etc.), the melting point is measured under the following conditions.

·Temperature increase rate: 2℃/min

·Measurement temperature: -20℃ to 300℃

(3) The melting points (°C) of the core component and cis component obtained in (2) are rounded to one decimal place.

(4) A measurement sample is again taken from the spunbond nonwoven fabric, treated with alkali, and the sheath component is eluted to produce a yarn containing only the core component.

(5) 5 mg of the sample obtained in (4) is collected, and pretreatment is performed in the same manner as in (1).

(6) DSC measurement is performed similarly to (2) and (3), and the melting point of the core component is measured.

(7) Determine the melting point of the cis component from the melting point obtained in (4) and (6).

The composite mass ratio (core:sheath) of the core sheath type composite fiber in the present invention is 50% by mass to 95% by mass of the core component (composite mass ratio (core:sheath) is 95:5 to 50:50). It is desirable. The core component is 50% by mass or more (composite mass ratio (core: sheath) is ~50:50, the same applies hereinafter), more preferably 60% by mass or more (~60:40), even more preferably 70% by mass or more ( ~70:30), the low melting point polymer of the cis component can suppress excessive adhesion during heat compression. Therefore, the weight per unit area of the nonwoven fabric can be controlled, and a decrease in the permeability of the separator forming component into the nonwoven fabric can be suppressed. Suppression of a decrease in permeability of the separator forming component can suppress a decrease in the peel strength of the separator in order to improve adhesion to the separator. On the other hand, the composite mass ratio of the core components is 95 mass% or less (95:5 ~), more preferably 90 mass% or less (90:10 ~), and even more preferably 80 mass% or less (80: By setting it to 20~), the weight per unit area of the nonwoven fabric can be controlled so that the low melting point polymer of the cis component can easily adhere. By controlling the weight per unit area of the nonwoven fabric, the permeability of the separator forming component is improved and the adhesiveness of the separator is improved. By improving adhesion, the peel strength of the separator can also be improved.

The single yarn fineness of the core sheath type composite fiber constituting the spunbond nonwoven fabric is preferably 0.1 dtex to 3.0 dtex, more preferably 0.3 dtex to 2.5 dtex, and still more preferably 0.5 dtex to 2.0 dtex. If the single yarn fineness of the filaments constituting the spunbond nonwoven fabric is 0.1 dtex or more, there is little decrease in radioactivity during the production of the spunbond nonwoven fabric, and when used as a separator support, breathability can be maintained, so the polymer solution softened during film formation It is possible to obtain a good spunbond nonwoven fabric that penetrates quickly into the separator support and has less membrane peeling. On the other hand, if the single yarn fineness of the filaments constituting the spunbonded nonwoven fabric is 3.0 dtex or less, when used as a separator support, the density can be increased, so overpermeation during polymer solution stretching is less and a good spunbonded nonwoven fabric can be obtained. Additionally, core-sheath composite fibers of different fineness may be mixed.

The average single fiber diameter of the core sheath type composite fibers constituting the spunbond nonwoven fabric is preferably 3 μm to 30 μm, more preferably 5 μm to 25 μm, and still more preferably 7 μm to 20 μm. If the average single fiber diameter of the filaments constituting the spunbonded nonwoven fabric is 3㎛ or more, there is little decrease in radioactivity during the production of the spunbonded nonwoven fabric, and when used as a separator support, breathability can be maintained, so it is flexible during film formation. The polymer solution quickly penetrates into the separator support, and a good spunbond nonwoven fabric with less membrane peeling can be obtained. On the other hand, if the average single fiber diameter of the filaments constituting the spunbond nonwoven fabric is 30㎛ or less, when used as a separator support, the density can be increased, so overpermeation during polymer solution stretching is less and a good spunbonded nonwoven fabric can be obtained. Additionally, core-sheath composite fibers having different average single fiber diameters may be mixed.

[Spunbond nonwoven fabric]

The present invention is a spunbond nonwoven fabric manufactured by the spunbond method. Spunbond nonwoven fabric, which is a long-fiber nonwoven fabric composed of thermoplastic filaments, when used as a separator support, can suppress unevenness and membrane defects during polymer solution stretching due to fluffing, which tend to occur when using short-fiber nonwoven fabric. In addition, spunbond nonwoven fabric has excellent mechanical strength, and when used as a separator support, a highly durable separator can be obtained.

The spunbond nonwoven fabric of the present invention can be used as a single layer or by laminating multiple layers of nonwoven fabric, but it can easily adjust the uniformity of weight per unit area, density distribution in the thickness direction, and smoothness of the front and back surfaces. , it is preferable to use them in a stacked manner. When stacking, the number of layers is preferably 2 to 5, and if the number of layers is 2 or more, sufficient uniformity of weight per unit area is obtained compared to a single layer. Additionally, by setting the number of layers to 5 or less, wrinkles and separation between layers can be suppressed during lamination. The spunbond nonwoven fabric laminated in this way is suitably used because, even when used as a separator support, the presence of interlayers suppresses over-permeation during polymer solution casting and reduces back-bleeding.

The amount of polyethylene glycol copolymerization of the spunbond nonwoven fabric in the present invention is 2% by mass or more and 15% by mass or less with respect to the copolyester. The amount of copolymerization is preferably 4% by mass or more, more preferably 8% by mass or more, so that the permeability of the separation membrane forming component can be improved. On the other hand, by setting the copolymerization amount to preferably 14% by mass or less, yarn breakage due to the attitude during spinning can be suppressed, and further, the strength of the spunbond nonwoven fabric can be increased.

By keeping the copolymerization amount of polyethylene glycol within the above range, hydrophilicity improves and the contact angle of the spunbond nonwoven fabric with respect to water decreases. As a result, permeability with the separation membrane forming component is improved. As the hydrophilicity of the non-woven fabric surface improves, the polymer components that make up the separator quickly penetrate into the non-woven fabric, and the adhesion between the non-woven fabric and the separator becomes stronger.

In addition, the amount of polyethylene glycol copolymerization of the spunbond nonwoven fabric refers to the value measured and calculated by the method described above.

The amount of the isophthalic acid component containing a metal sulfonate group in the spunbond nonwoven fabric in the present invention is 2.5 mol% or more and 7.5 mol% or less with respect to the total acid components. Permeability with the separation membrane forming component can be improved by setting it to 2.5 mol% or more, preferably 3.0 mol% or more, relative to the total acid component. On the other hand, by setting the copolymerization amount to 7.5 mol% or less, preferably 7.0 mol% or less, based on the total acid component, yarn breakage due to an increase in the extensional viscosity of the cis component during spinning can be suppressed, and further, spunbond The strength of nonwoven fabric can be increased.

By setting the isophthalic acid component containing a metal sulfonate group within the above range, hydrophilicity improves and the contact angle of the spunbond nonwoven fabric with respect to water decreases. As a result, the polymer solution constituting the separator quickly penetrates into the nonwoven fabric, the adhesion between the nonwoven fabric and the separator is strengthened, and a spunbond nonwoven fabric excellent as a separator support can be obtained.

In addition, the amount of the isophthalic acid component containing a metal sulfonate group in the spunbond nonwoven fabric refers to the value measured and calculated by the method described above.

The weight per unit area of the spunbond nonwoven fabric of the present invention is preferably 20 g/m2 to 150 g/m2. The weight per unit area is more preferably 30 g/m2 or more, and even more preferably 40 g/m2 or more, so that when the nonwoven fabric is used as a separator support, high mechanical strength and excellent dimensional stability are achieved. On the other hand, the weight per unit area is more preferably 120 g/m 2 or less, and even more preferably 90 g/m 2 or less, so that when non-woven fabric is used as a separator support, the thickness of the separator is reduced, and the number of separator layers per separator unit is reduced. can be increased, and filtration performance can be improved.

The weight per unit area of each spunbond nonwoven fabric to be laminated is not limited at all as long as the weight per unit area of the final separator support is in the range of 20 g/m2 to 150 g/m2, for example, 3 with a weight per unit area of 10 g/m2. It is determined appropriately depending on the product design, such as a single stack or two stacks of 30 g/m2.

The thickness of the spunbond nonwoven fabric of the present invention is appropriately determined depending on the application or product design, but is preferably 0.01 mm to 1.00 mm, and more preferably 0.03 mm to 0.80 mm. If the thickness of the spunbond nonwoven fabric is 0.01 mm or more, a spunbond nonwoven fabric with excellent mechanical strength and durability can be obtained. On the other hand, if the thickness of the spunbond nonwoven fabric is 1.00 mm or less, the rigidity does not become too high and the handling properties are excellent. Additionally, when used as a separator support, the thickness is preferably 0.03 mm to 0.20 mm, more preferably 0.04 mm to 0.16 mm, and still more preferably 0.05 mm to 0.12 mm. If the thickness is 0.03 mm or more, the mechanical strength and dimensional stability as a separator support are excellent. On the other hand, if the thickness of the nonwoven fabric is 0.20 mm or less, the separator forming component can penetrate into the nonwoven fabric, and the adhesion between the nonwoven fabric and the separator is improved, thereby achieving high membrane peel strength.

The density of the spunbond nonwoven fabric of the present invention is preferably 0.5 g/cm3 to 1.8 g/cm3. The density is more preferably 0.6 g/cm3 or more, and even more preferably 0.7 g/cm3 or more, so that high mechanical strength and excellent dimensional stability are achieved when used as a separator support. On the other hand, the density is more preferably 1.4 g/cm3 or less, and even more preferably 1.0 g/cm3 or less, so that when used as a separator support, the thickness of the separator is reduced and the number of layers of the separator per separator unit is reduced. can be increased, and filtration performance can be improved.

The spunbond nonwoven fabric of the present invention preferably has an arithmetic mean roughness of the surface of the nonwoven fabric of 0.1 μm or more and 10 μm or less. By setting the arithmetic average roughness to 0.1 ㎛ or more, more preferably 0.2 ㎛ or more, when used as a separator support, breathability can be maintained, so that the polymer solution softened during film formation quickly penetrates into the interior of the separator support, and adheres to the separator. With improved properties, it is possible to provide a separator support with excellent membrane peeling strength and less peeling from the separator. On the other hand, by setting the arithmetic mean roughness to 10 ㎛ or less, more preferably 8 ㎛ or less, when used as a separator support, surface smoothness is improved and the polymer solution constituting the separator can be uniformly formed on the surface of the membrane substrate, It is possible to provide a separator support with excellent membrane peeling strength with little peeling from the separator.

The spunbond nonwoven fabric of the present invention has a contact angle with water on the surface of the spunbond nonwoven fabric of 0° or more and 80° or less. The contact angle with water is set to 0° or more, preferably 5° or more, more preferably 10° or more, especially preferably 15° or more, so that when used as a separation membrane support, the back of the polymer solution constituting the separation membrane It is possible to suppress bleeding, and when forming a composite membrane, a separator composed of a polymer component can maintain a sufficient thickness as a support layer. On the other hand, by setting the contact angle with water to 80° or less, preferably less than 70°, more preferably 50° or less, and even more preferably 40° or less, the hydrophilicity of the surface of the nonwoven fabric is improved, and it can be used as a separator support. When doing so, the polymer solution constituting the separator quickly penetrates into the nonwoven fabric, the adhesion with the separator is improved, and a separator support with excellent peel strength with less peeling from the separator can be provided.

In order for the spunbond nonwoven fabric of the present invention to be used for water treatment purposes, it is desirable to be able to suppress the amount of leaching of the internal material into water, and the amount of leaching is measured according to the water method test (JIS S3200-7:2010 "Waterwork Appliances - Leaching Performance Test Method" 」) is defined by the total organism carbon content (TOC amount). The amount of TOC is an indicator of water contamination, and the specified value in tap water is 3 mg/L or less, and spunbond nonwoven fabrics used for water treatment must meet this standard. Therefore, the TOC amount of the spunbonded nonwoven fabric of the present invention is preferably 3.0 mg/L or less, more preferably 2.5 mg/L or less, and even more preferably 1.5 mg/L or less, so that the spunbond nonwoven fabric can be used as a separator support. When used, it can indicate that there are few impurities in the separated liquid.

[Method for manufacturing spunbond nonwoven fabric]

Next, the manufacturing method of the spunbond nonwoven fabric of the present invention will be described in detail.

The spunbond method for producing spunbond nonwoven fabric is to melt the resin, spin it from a spinneret, cool and solidify the obtained yarn, pull it with an ejector, stretch it, collect it on a moving net, and form it into a fiber web. , a manufacturing method that requires a heat bonding process. The shape of the spinneret or ejector used can be various, such as circular or rectangular. Among them, it is a preferable mode to use a combination of a rectangular spinneret and a rectangular ejector from the viewpoint that the amount of compressed air used is relatively small and fusion or abrasion of threads is unlikely to occur.

In the present invention, the copolyester containing polyester as the core component, polyethylene glycol as the cis component, and/or isophthalic acid component containing a metal sulfonate group is vacuum dried, melted in an extruder, measured, and supplied to a spinneret. Released as long fibers. The discharged long fiber yarn is cooled, solidified, and pulled and stretched by compressed air sprayed from the ejector.

In order to improve the strength of the long fibers that contribute to the mechanical strength of the nonwoven sheet, the spinning speed is preferably 2000 m/min or more, more preferably 3000 m/min or more, and even more preferably 3500 m/min or more. It can be highly oriented and crystallized. On the other hand, excessive orientation crystallization of long fibers impairs thermal adhesiveness, and the spinning speed is preferably 5500 m/min or less, more preferably 5000 m/min or less, and even more preferably 4500 m/min or less. In addition, excessive orientation crystallization causes shrinkage of the fibers and causes deformation such as bending or rounding of the spunbond nonwoven fabric, so the above spinning speed is preferable. In the case of the spunbond method, the spinning speed can be controlled by adjusting the suction pressure during suction stretching by high-speed suction gas.

Next, the obtained long fibers are collected on a moving net, formed into a fiber web, and integrated by continuous heat compression and entanglement, etc., to obtain a spunbond nonwoven fabric.

Subsequently, the obtained spunbond nonwoven fabric is laminated and heat-compressed to obtain a separator support. As a method, a method of laminating temporary bonded spunbond nonwoven fabrics obtained by the spunbond method and then bonding them by thermal compression is preferable. Thermocompression bonding includes methods such as thermal bonding using a combination of flat rolls, piece rolls, etc., and entangling using needle punches, water jet punches, etc.; however, unevenness or pinhole defects in the film may occur due to fluffing, etc. It is desirable to have excellent weight uniformity and surface smoothness per unit area. Therefore, it is preferable to integrate the nonwoven fabric sheet with a pair of upper and lower flat rolls. In addition, by suppressing fiber fusion and irregularities on the surface of the spunbond nonwoven fabric and maintaining its shape, when used as a separator support, the separator forming component penetrates into the nonwoven fabric and the adhesive properties of the separator are obtained, so the heated metal roll and A heat compression method using a non-heated elastic roll is also preferably used. Examples of the elastic roll include so-called paper rolls such as paper, cotton, and aramid paper, and rolls made of resin such as urethane resin, silicone resin, and hard rubber.

[Uses of spunbond nonwoven fabric]

The separation membrane using the spunbond nonwoven fabric of the present invention is a separation membrane formed by forming a membrane with a separation function on a spunbond nonwoven fabric after heat compression, that is, a separation membrane support, and examples include microfiltration membrane, ultrafiltration membrane, nanofiltration membrane and reverse osmosis membrane. Semipermeable membranes such as these can be mentioned.

As a method of manufacturing the separation membrane, a method of forming a separation membrane by softening a polymer solution on at least one surface of a separation membrane support to form a membrane having a separation function is preferably used. In addition, when the separation membrane is a semipermeable membrane, it is also preferable that the membrane having the separation function be a composite membrane including a support layer and a semipermeable membrane layer (in this case, the support layer may not have a separation function).

The polymer component in the polymer solution that is flexible on the separation membrane support has a separation function after film formation, and this polymer component includes a group consisting of polysulfone, polyethersulfone, polyarylethersulfone, polyimide, polyvinylidene fluoride, and cellulose acetate. It is preferable that it is at least one type selected from. Among these, from the viewpoint of chemical, mechanical and thermal stability, a solution of polysulfone or a solution of polyarylether sulfone is preferably used. The solvent can be appropriately selected depending on the film forming material. Additionally, in the case where the separation membrane is a composite membrane including a support layer and a semipermeable membrane layer, a crosslinked polyamide membrane obtained by polycondensation of a polyfunctional acid halide and a polyfunctional amine, etc. is preferably used as the semipermeable membrane.

In the separator comprising the spunbond nonwoven fabric of the present invention, the penetration rate of the polymer solution into the nonwoven fabric is preferably 5% or more and 70% or less, more preferably 10% or more and 60% or less, and even more preferably 15% or more. It is less than 50%. In addition, the penetration rate of the polymer solution is calculated as the area occupied by the polymer component per unit area of the nonwoven fabric by performing cross-sectional observation after forming the separator.

((Area occupied by polymer component)/(Area of non-woven fabric)) × 100 = Penetration rate (%)

As the penetration rate improves, the adhesion between the separator composed of polymer components and the spunbond nonwoven fabric, which is the separator support, improves, and high membrane peel strength can be obtained. On the other hand, the penetration rate of the polymer solution is preferably 70% or less, more preferably 60% or less, and even more preferably 50% or less. By setting it to 50% or less, spillage of the polymer solution can be suppressed, and when forming a composite membrane, the separator composed of the polymer component can maintain a sufficient thickness as a support layer.

The peeling strength of the separation membrane from the separation membrane support of the present invention is preferably 0.30 N/15 mm or more at any location, more preferably 0.70 N/15 mm or more, and still more preferably 1.00 N/15 mm or more. As the membrane peeling strength improves, peeling of the separator from the spunbond nonwoven fabric can be suppressed and film forming properties improve. Additionally, it is possible to provide a separation membrane that can prevent fluctuations in operating pressure or delamination under high pressure when used as a separation element unit.

The use of the spunbond nonwoven fabric of the present invention is assumed to be a support membrane for water treatment, but other uses include, for example, filters, filter substrates, industrial materials such as wire press winding materials, wallpaper, moisture-permeable waterproofing sheets, and roof lowers. Construction materials such as flooring materials, sound insulating materials, insulation materials, and sound absorbing materials, household materials such as wrapping materials, pouch materials, sign materials, and printing materials, civil engineering materials such as weed control sheets, drainage materials, ground reinforcement materials, sound insulating materials, and sound absorbing materials, mulching materials, and shading materials. It can also be suitably used for agricultural materials such as seats, vehicle materials such as ceiling materials and spare tire cover materials, etc.

Example

Below, the spunbond nonwoven fabric of the present invention will be described in detail based on examples. These are examples, and the present invention is not limited to these. The physical property values of the above-described separator support, the spunbond nonwoven fabric constituting the separator support, and the core sheath type composite fibers constituting the spunbond nonwoven fabric, as well as each physical property value in the examples, were measured by the following method.

(1) Melting point of polymer (℃)

The melting point of the polymer was measured using differential scanning calorimetry (DSC).

Device: “Q-2000” manufactured by TA Instruments

Temperature increase rate: 2℃/min,

Measuring temperature: -20℃ to 300℃.

(2) Radioactivity evaluation

Copolymerized polyester was used as the cis component, discharged from the pores at a spinneret temperature of 300°C and a predetermined composite mass ratio, and then spun at a spinning speed of 4000 m/min by an ejector. Based on the number of yarn breaks, the spinability was S, It was evaluated in three levels, A and B.

Rating S: No thread breaks per hour

Evaluation A: The number of thread breaks per hour is between 1 and 10 times.

Evaluation B: The number of thread breaks per hour is 11 or more.

(3) Single yarn fineness (dtex)

For single yarn fineness, 10 small samples were randomly collected from the spunbond nonwoven fabric, photographs were taken at 500 to 3000 times with a scanning electron microscope (“VHX-2000” manufactured by Keyence Co., Ltd.), and 10 samples were taken from each sample. The diameters of a total of 100 single fibers were measured, and their average values were obtained by correcting the density of the polymer and rounding off to two decimal places.

(4) Average single fiber diameter (㎛)

For the average single fiber diameter, 10 small samples were randomly collected from the spunbond nonwoven fabric, photographs were taken at 500 to 3000 times with a scanning electron microscope (“VHX-2000” manufactured by Keyence Co., Ltd.), and 10 samples were taken from each sample. The diameters of a total of 100 single fibers were measured one by one, and their average value was obtained by rounding to one decimal place.

(5) Amount of polyethylene glycol copolymerization (% by mass) in the spunbond nonwoven fabric, and the amount of copolymerization (% by mass) of polyethylene glycol in the sheath component of the core sheath type composite fiber contained in the spunbond nonwoven fabric.

The copolymerization amount of polyethylene glycol was measured and calculated by the method described above using “AL-400” manufactured by Nippon Electronics Co., Ltd. as a measuring device.

(6) Copolymerization amount (mol%) of the isophthalic acid component containing a metal sulfonate group relative to the total acid component in the sheath component of the core sheath type composite fiber of the spunbond nonwoven fabric, the core sheath type composite fiber contained in the spunbond nonwoven fabric Copolymerization amount (mol%) of the isophthalic acid component containing a metal sulfonate group relative to the total acid component in the cis component of

The amount of copolymerization of the isophthalic acid component containing a metal sulfonate group relative to the total acid component in the cis component was measured and calculated by the method described above using “AL-400” manufactured by Nippon Electronics Co., Ltd. as a measuring device. was carried out.

(7) Weight per unit area of spunbond nonwoven fabric (g/㎡)

Three 30cm x 50cm spunbond nonwoven fabrics were sampled, the weight of each sample was measured, and the average of the obtained values was converted to per unit area and rounded to one decimal place.

(8) Thickness of spunbond nonwoven fabric (mm)

The thickness of the spunbond nonwoven fabric was determined by randomly collecting 10 small piece samples, using a micrometer manufactured by Mitsutoyo Co., Ltd., sandwiching the nonwoven fabric with an anvil and spindle with a diameter of 6 mm, and measuring 2 points within the small piece sample. Measurements were made at equal intervals to the nearest 0.01 mm, and the average value of the total of 20 points was rounded to three decimal places.

(9) Density of spunbond nonwoven fabric (g/cm3)

The weight per unit area of the spunbond nonwoven fabric was divided from the thickness of the spunbond nonwoven fabric and rounded to three decimal places.

(10) Arithmetic surface roughness of spunbond nonwoven fabric (㎛)

The arithmetic surface roughness (Ra) of the spunbond nonwoven fabric was determined by the line roughness at 1000 μm using a light transmission method using a laser microscope. For level 1, the measurement position was changed and measured 10 times, and the average value excluding the maximum and minimum values was rounded to the first decimal place and calculated. As the arithmetic surface roughness decreases, the smoothness of the surface of the nonwoven fabric improves, and the adhesion of the separator to the nonwoven fabric improves.

Device: “VK-X200” manufactured by Keyence Corporation.

(11) Contact angle of spunbond nonwoven fabric with water (°)

The contact angle (°) of the surface of the spunbond nonwoven fabric with water was obtained by depositing a 2 μL droplet containing ion-exchanged water on the spunbonded nonwoven fabric and obtaining it from an image taken 1 second after the contact. For level 1, the measurement position was changed and measurements were made 10 times, the average value was calculated excluding the maximum and minimum values, the contact angle with water was calculated, and the contact angle with water was rounded to one decimal place. A lower contact angle means that the hydrophilicity of the surface of the nonwoven fabric improves. As the hydrophilicity increases, the penetration rate of the separator components into the nonwoven fabric improves, and the adhesion of the separator to the nonwoven fabric improves. In addition, in Tables 1 to 6, the measurement results of the contact angle (°) of the surface of the spunbond nonwoven fabric with water are simply abbreviated as “contact angle (°).”

(12) TOC amount of spunbond nonwoven fabric (mg/L)

The TOC amount of the spunbond nonwoven fabric is based on JIS S3200-7:2010 "Waterwork Appliances - Leaching Performance Test Method", and the nonwoven fabric is immersed in ion exchanged water for 1 hour at 25°C so that the bath ratio for the spunbonded nonwoven fabric is 100. The nonwoven fabric after immersion was washed six times with 50 mL of ion-exchanged water and immersed again for 16 hours at 25°C. 0.5 mL of 2 mol/L hydrochloric acid was added dropwise to 20 mL of the solution after immersion, and after bubbling for 15 minutes, TOC analysis was performed. The lower the TOC amount, the smaller the amount of internal substances eluted with water, indicating that there are fewer impurities in the solution after filtration.

Device: Table-top TOC measuring instrument (“TNC-6000” manufactured by Toray Engineering Co., Ltd.)

In addition, in Tables 1 to 6, the measurement results of the TOC amount (mg/L) of the spunbond nonwoven fabric are simply abbreviated as “TOC amount (mg/L).”

(13) Penetration rate (%) of polymer components into spunbond nonwoven fabric

The penetration rate of the polymer component constituting the separator into the spunbond nonwoven fabric was calculated as the area occupied by the polymer component per unit area of the spunbond nonwoven fabric by performing cross-sectional observation after forming the separator on the surface of the spunbond nonwoven fabric. The higher the penetration rate, the higher the adhesion between the spunbond nonwoven fabric and the separator, and the separator does not peel off from the spunbond nonwoven fabric and the film forming property improves.

((Area occupied by polymer component)/(Area of non-woven fabric))×100=Penetration rate (%)

In addition, in Tables 1 to 6, the measurement results of the penetration rate (%) of the polymer component into the spunbond nonwoven fabric are abbreviated as “PSf penetration rate (%).”

(14) Peel strength of separator (N/15㎜)

The produced polysulfone separation membrane (PSf membrane) was cut into 15 mm in the overall width direction and 13 cm in the length direction, and a Kikusui Tape Co., Ltd. keycraft tape was attached to the PSf membrane surface, and the PSf layer at one end was 8 cm in the longitudinal direction. The material is removed from the separator support, the PSf layer is fixed on one side of the gripping part of the constant-speed extension type tensile tester, and the spunbond nonwoven fabric as the separator support is fixed on the other side, the gripping interval is 15 mm, and the tensile speed is 15 mm/min. Under these conditions, the strength is measured, the average value of the strength from the stable gripping distance of 15 mm to 75 mm is calculated, the value rounded to three decimal places is taken as the film peel strength, and the average value (N/ 15 mm) was taken as the peeling strength of the separator (average value of (N=5)). In addition, in Tables 1 to 6, the measurement results of the peel strength of the separator (N/15 mm) are indicated as “Peel strength of the PSf film (N/15 mm).”

[Example 1]

Polyethylene terephthalate (PET) with a melting point of 255°C and 0.3% by mass of titanium oxide was used as a core component, an isophthalic acid component of 11.5mol% relative to the total acid component, and polyethylene glycol (PEG) with a number average molecular weight of 20000 ( 2% by mass of PEG20000 manufactured by Sanyo Kasei Kogyo Co., Ltd. was copolymerized, and copolymerized polyethylene terephthalate (PET/I-PEG) with a melting point of 230°C and containing 0.2% by mass of titanium oxide was used as the cis component. The core component and sheath component are melted at a temperature of 295°C and 270°C, respectively, discharged from the pores at a spindle temperature of 300°C and a mass ratio of core:sheath=80:20, and then spun at a spinning speed of 4000 m/min by an ejector. It was formed into a concentric core sheath-shaped filament (circular cross-section) whose entire surface was covered with polyethylene terephthalate containing polyethylene glycol, and collected as a fiber web on a moving net conveyor. The collected fiber web is heat-bonded using an upper and lower pair of emboss rolls at a heat bonding temperature of 120°C, and the single yarn fineness of the constituent filaments is 1.9 dtex, the average single fiber diameter is 14 ㎛, and the weight per unit area is. This 35g/m2 spunbond nonwoven fabric was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were overlapped and heat-compressed to produce a spunbonded nonwoven fabric with a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, and an arithmetic mean surface roughness of 10 ㎛. A bonded nonwoven laminate was obtained. The contact angle of the obtained spunbond nonwoven fabric laminate was 70°, and the TOC amount was 0.9 mg/L.

A polymer solution containing polysulfone (PSf) dissolved in N,N-dimethylformamide (DMF) was casted on the obtained spunbond nonwoven laminate to form a separator film. At this time, the penetration rate into the polysulfone nonwoven fabric laminate was 12%, and the peeling strength of the polysulfone film from the nonwoven fabric laminate was 0.88 N/15 mm. The results are shown in Table 1.

[Example 2-4]

The same method as Example 1 was carried out except that 4 mass%, 8 mass%, and 14 mass% of PEG (PEG20000 manufactured by Sanyo Kasei Kogyo Co., Ltd.) with a number average molecular weight of 20000 was copolymerized, and polyethylene terephthalate containing polyethylene glycol was copolymerized. A spunbond nonwoven fabric with a single yarn fineness of 1.9dtex, an average single fiber diameter of 14㎛, and a weight per unit area of 35g/m2 of the constituent filaments covering the entire surface was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbond nonwoven laminate, Example 2, had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 9 μm, a contact angle of 60°, and a TOC amount of 1.1. It was mg/L. Additionally, the penetration rate of polysulfone was 13%, and the film peel strength was 1.03 N/15 mm.

Example 3 had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic average roughness of the surface of 8 μm, a contact angle of 40°, and a TOC amount of 1.4 mg/L. In addition, the penetration rate of polysulfone was 15%, and the film peel strength was 1.47 N/15 mm.

In Example 4, the weight per unit area was 70g/m2, the thickness was 0.10mm, the density was 0.70g/cm3, the arithmetic mean surface roughness was 6㎛, the contact angle was 15°, and the TOC amount was 2.5mg/L. Additionally, the penetration rate of polysulfone was 25%, and the film peel strength was 2.35 N/15 mm. The results are shown in Table 1.

[Example 5-7]

The same method as Example 1 was carried out except that 2% by mass, 8% by mass, and 14% by mass of PEG (PEG6000S manufactured by Sanyo Kasei Kogyo Co., Ltd.) with a number average molecular weight of 7000 was copolymerized, and polyethylene terephthalate containing polyethylene glycol was copolymerized. A spunbond nonwoven fabric with a single yarn fineness of 1.9dtex, an average single fiber diameter of 14㎛, and a weight per unit area of 35g/m2 of the constituent filaments covering the entire surface was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbond nonwoven laminate, Example 5, had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 11 μm, a contact angle of 65°, and a TOC amount of 0.7. It was mg/L. Additionally, the penetration rate of polysulfone was 10%, and the film peel strength was 0.71 N/15 mm.

Example 6 had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 9 μm, a contact angle of 60°, and a TOC amount of 1.2 mg/L. Additionally, the penetration rate of polysulfone was 13% and the film peel strength was 0.98N/15mm.

Example 7 had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 8 μm, a contact angle of 20°, and a TOC amount of 1.9 mg/L. In addition, the penetration rate of polysulfone was 21%, and the film peel strength was 1.96 N/15 mm. The results are shown in Table 1.

[Example 8]

As a cis component, 22 mol% of isophthalic acid component is copolymerized with respect to all acid components, and 8 mass% of PEG (PEG20000 manufactured by Sanyo Kasei Kogyo Co., Ltd.) with a number average molecular weight of 20000 is copolymerized, the melting point is 210°C, and titanium oxide is contained 0.2 mass%. The same method as Example 1 was carried out except that copolyester containing A spunbond nonwoven fabric weighing 35 g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The weight per unit area of the obtained spunbond nonwoven fabric laminate was 70 g/m2, the thickness was 0.07mm, the density was 1.00g/cm3, the arithmetic mean surface roughness was 5㎛, the contact angle was 41°, and the TOC amount was 2.3mg/L.

A polymer solution containing polysulfone dissolved in DMF was softened on the obtained spunbond nonwoven fabric laminate to form a separator film. At this time, the penetration rate into the polysulfone nonwoven fabric laminate was 11%, and the peeling strength of the polysulfone film from the nonwoven fabric laminate was 0.74 N/15 mm. The results are shown in Table 1.

[Example 9]

As a cis component, 8.0 mol% of the isophthalic acid component and 8 mass% of PEG (PEG20000 manufactured by Sanyo Kasei Kogyo Co., Ltd.) with a number average molecular weight of 20000 were copolymerized relative to the total acid components, and the melting point was 240°C, and titanium oxide was copolymerized at 0.2 mass%. The same method as Example 1 was carried out except that a copolyester containing polyester was used, and the entire surface of the constituent filament was covered with polyethylene terephthalate containing polyethylene glycol. A spunbond nonwoven fabric with a weight per area of 35 g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The weight per unit area of the obtained spunbond nonwoven fabric laminate was 70 g/m, thickness was 0.14 mm, density was 0.50 g/cm, surface arithmetic mean roughness was 11 μm, contact angle was 42°, and TOC amount was 1.5 mg/L.

A polymer solution containing polysulfone dissolved in DMF was softened on the obtained spunbond nonwoven fabric laminate to form a separator film. At this time, the penetration rate into the polysulfone nonwoven fabric laminate was 12%, and the peeling strength of the polysulfone film from the nonwoven fabric laminate was 0.93 N/15 mm. The results are shown in Table 1.

[Example 10-12]

14% by mass of PEG with a number average molecular weight of 1000 (PEG1000, manufactured by Sanyo Kasei Kogyo Co., Ltd.), PEG with a number average molecular weight of 3400 (PEG4000S, manufactured by Sanyo Kasei Kogyo Co., Ltd.), and PEG with a number average molecular weight of 35,000 (PEG35000, manufactured by Sigma Aldrich). was carried out in the same manner as in Example 1 except that 8 mass% copolymerization was performed, and the entire surface of the constituent filament covered with polyethylene terephthalate containing polyethylene glycol had a single yarn fineness of 1.9 dtex, an average single fiber diameter of 14 ㎛, and a per unit area. A spunbond nonwoven fabric weighing 35 g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbond nonwoven laminate, Example 10, had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 11 μm, a contact angle of 80°, and a TOC amount of 0.9. It was mg/L. Additionally, the penetration rate of polysulfone was 5%, and the film peel strength was 0.31 N/20 mm.

Example 11 had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 11 μm, a contact angle of 77°, and a TOC amount of 0.9 mg/L. Additionally, the penetration rate of polysulfone was 6% and the film peel strength was 0.34 N/15 mm.

Example 12 had a weight per unit area of 70 g/m2, a thickness of 0.06 mm, a density of 1.17 g/cm3, an arithmetic mean surface roughness of 8 μm, a contact angle of 20°, and a TOC amount of 3.5 mg/L. Additionally, the penetration rate of polysulfone was 8%, and the film peel strength was 0.41 N/20 mm. The results are shown in Table 2.

[Example 13-17]

Except that the mass ratio of the core component and the cis component was changed to 95:5, 90:10, 70:30, 60:40, and 50:50, the same method as Example 3 was carried out, and polyethylene terephthalate containing polyethylene glycol was used. A spunbond nonwoven fabric with a single yarn fineness of 1.9dtex, an average single fiber diameter of 14㎛, and a weight per unit area of 35g/m2 of the constituent filaments covering the entire surface was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbond nonwoven laminate of Example 13 had a weight per unit area of 70 g/m2, a thickness of 0.13 mm, a density of 0.54 g/cm3, an arithmetic mean surface roughness of 12 ㎛, a contact angle of 41°, and a TOC amount of 0.9 mg. It was /L. Additionally, the penetration rate of polysulfone was 8%, and the film peel strength was 0.39 N/15 mm.

Example 14 had a weight per unit area of 70 g/m2, a thickness of 0.12 mm, a density of 0.58 g/cm3, an arithmetic average roughness of the surface of 9 μm, a contact angle of 40°, and a TOC amount of 1.1 mg/L. Additionally, the penetration rate of polysulfone was 11% and the film peel strength was 0.76N/15mm.

Example 15 had a weight per unit area of 70g/m2, a thickness of 0.08mm, a density of 0.86g/cm3, an arithmetic mean surface roughness of 7㎛, a contact angle of 41°, and a TOC amount of 1.8mg/L. Additionally, the penetration rate of polysulfone was 14% and the film peel strength was 1.08 N/15 mm.

Example 16 had a weight per unit area of 70 g/m2, a thickness of 0.05 mm, a density of 1.40 g/cm3, an arithmetic mean surface roughness of 6 μm, a contact angle of 39°, and a TOC amount of 2.2 mg/L. In addition, the penetration rate of polysulfone was 12%, and the film peel strength was 0.83 N/15 mm.

Example 17 had a weight per unit area of 70 g/m2, a thickness of 0.04 mm, a density of 1.75 g/cm3, an arithmetic mean surface roughness of 5 μm, a contact angle of 40°, and a TOC amount of 2.7 mg/L. Additionally, the penetration rate of polysulfone was 7% and the film peel strength was 0.34 N/15 mm. The results are shown in Table 2.

[Example 18]

Polyethylene terephthalate (PET), which has a melting point of 255°C and contains 0.3% by mass of titanium oxide, is used as a core component, and isophthalic acid is used at 9.5mol% and sodium 5-sulfoisophthalate (SSIA) relative to the total acid component. A copolyester (PET/I-SSIA) copolymerized with 2.5 mol%, having a melting point of 230°C, and containing 0.2% by weight titanium oxide was used as the cis component. The core component and sheath component are melted at a temperature of 295°C and 270°C, respectively, discharged from the pores at a spindle temperature of 300°C and a mass ratio of core:sheath=80:20, and then spun at a spinning speed of 4000 m/min by an ejector. It was formed into a concentric core sheath-type filament (circular cross-section) whose entire surface was covered with polyethylene terephthalate containing a component derived from sodium 5-sulfoisophthalate, and collected as a fiber web on a moving net conveyor. The collected fiber web was thermocompressed using a pair of upper and lower emboss rolls to produce a spunbond nonwoven fabric with a single yarn fineness of constituent filaments of 1.4 dtex, an average single fiber diameter of 12 μm, and a weight per unit area of 35 g/m2.

Two sheets of the obtained spunbonded nonwoven fabric were overlapped and thermally compressed to produce a spunbonded nonwoven fabric with a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, and an arithmetic mean surface roughness of 12 ㎛. A bonded nonwoven laminate was obtained. The contact angle of the obtained spunbond nonwoven fabric laminate was 66°, and the TOC amount was 1.2 mg/L.

A polymer solution containing polysulfone (PSf) dissolved in N,N-dimethylformamide (DMF) was casted on the obtained spunbond nonwoven laminate to form a separator film. At this time, the penetration rate into the polysulfone nonwoven fabric laminate was 13%, and the peeling strength of the polysulfone film from the nonwoven fabric laminate was 0.54 N/15 mm. The results are shown in Table 3.

[Example 19]

As a cis component, 9.5 mol% of isophthalic acid and 5.0 mol% of sodium 5-sulfoisophthalate are copolymerized with respect to all acid components, and a copolyester with a melting point of 230°C and 0.2% by weight of titanium oxide is used. It was carried out in the same manner as in Example 18, and the entire surface of the constituent filament covered with polyethylene terephthalate containing a component derived from sodium 5-sulfoisophthalate had a single yarn fineness of 1.4 dtex, an average single fiber diameter of 12 μm, and a per unit area. A spunbond nonwoven fabric weighing 35 g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 18, to obtain a spunbonded nonwoven fabric laminate. The weight per unit area of the obtained spunbond nonwoven fabric laminate was 70 g/m2, the thickness was 0.09mm, the density was 0.78g/cm3, the arithmetic mean roughness of the surface was 12㎛, the contact angle was 64°, and the TOC amount was 1.4mg/L.

A polymer solution containing polysulfone dissolved in DMF was softened on the obtained spunbond nonwoven fabric laminate to form a separator film. At this time, the penetration rate into the polysulfone nonwoven fabric laminate was 16%, and the peeling strength of the polysulfone film from the nonwoven fabric laminate was 0.62 N/15 mm. The results are shown in Table 3.

[Example 20]

As a cis component, 9.5 mol% of isophthalic acid and 7.5 mol% of sodium 5-sulfoisophthalate are copolymerized with respect to all acid components, and a copolyester with a melting point of 230°C and 0.2% by weight of titanium oxide is used. It was carried out in the same manner as in Example 18, and the entire surface of the constituent filament covered with polyethylene terephthalate containing a component derived from sodium 5-sulfoisophthalate had a single yarn fineness of 1.4 dtex, an average single fiber diameter of 12 μm, and a per unit area. A spunbond nonwoven fabric weighing 35 g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 18, to obtain a spunbonded nonwoven fabric laminate. The weight per unit area of the obtained spunbond nonwoven fabric laminate was 70 g/m2, the thickness was 0.09mm, the density was 0.78g/cm3, the arithmetic mean surface roughness was 12㎛, the contact angle was 59°, and the TOC amount was 1.6mg/L.

A polymer solution containing polysulfone dissolved in DMF was softened on the obtained spunbond nonwoven fabric laminate to form a separator film. At this time, the penetration rate into the polysulfone nonwoven fabric laminate was 25%, and the peeling strength of the polysulfone film from the nonwoven fabric laminate was 0.67 N/15 mm. The results are shown in Table 3.

[Example 21]

As a cis component, 20 mol% of isophthalic acid and 5.0 mol% of sodium 5-sulfoisophthalate were copolymerized with respect to the total acid components, and a copolymer polyester with a melting point of 210°C and 0.2% by weight of titanium oxide was used. It was carried out in the same manner as in Example 18, and the entire surface of the constituent filament covered with polyethylene terephthalate containing a component derived from sodium 5-sulfoisophthalate had a single yarn fineness of 1.4 dtex, an average single fiber diameter of 12 ㎛, and a weight per unit area. This 35g/m2 spunbond nonwoven fabric was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The weight per unit area of the obtained spunbond nonwoven fabric laminate was 70 g/m2, the thickness was 0.04mm, the density was 1.75g/cm3, the arithmetic mean roughness of the surface was 12㎛, the contact angle was 62°, and the TOC amount was 25mg/L.

A polymer solution containing polysulfone dissolved in DMF was softened on the obtained spunbond nonwoven fabric laminate to form a separator film. At this time, the penetration rate into the polysulfone nonwoven fabric laminate was 11%, and the peeling strength of the polysulfone film from the nonwoven fabric laminate was 0.51 N/15 mm. The results are shown in Table 3.

[Example 22]

As a cis component, 5.0 mol% of isophthalic acid and 5.0 mol% of sodium 5-sulfoisophthalate are copolymerized with respect to the total acid components, except that a copolyester having a melting point of 240°C and containing 0.2% by weight of titanium oxide is used. It was carried out in the same manner as in Example 18, and the entire surface of the constituent filament covered with polyethylene terephthalate containing a component derived from sodium 5-sulfoisophthalate had a single yarn fineness of 1.4 dtex, an average single fiber diameter of 12 μm, and a per unit area. A spunbond nonwoven fabric weighing 35 g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The weight per unit area of the obtained spunbond nonwoven fabric laminate was 70 g/m2, the thickness was 0.12mm, the density was 0.58g/cm3, the arithmetic mean roughness of the surface was 12㎛, the contact angle was 65°, and the TOC amount was 1.8mg/L.

A polymer solution containing polysulfone dissolved in DMF was softened on the obtained spunbond nonwoven fabric laminate to form a separator film. At this time, the penetration rate into the polysulfone nonwoven fabric laminate was 19%, and the peeling strength of the polysulfone film from the nonwoven fabric laminate was 0.53 N/15 mm. The results are shown in Table 3.

[Example 23-26]

The same method as Example 19 was carried out except that the mass ratio of the core component and the cis component was changed to 95:5, 90:10, 60:40, and 50:50, and a component derived from sodium 5-sulfoisophthalate was added. A spunbond nonwoven fabric with a single yarn fineness of 1.4dtex, an average single fiber diameter of 12㎛, and a weight per unit area of 35g/m2 of the constituent filaments whose entire surface was covered with polyethylene terephthalate was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were overlapped, and laminated processing was performed in the same manner as in Example 19, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbond nonwoven laminate has a weight per unit area of 70 g/m2, a thickness of 0.11 mm, a density of 0.64 g/cm3, an arithmetic mean surface roughness of 12 μm, and a contact angle of 12 μm when core:sheath = 95:5. At 65°, the TOC amount was 1.0 mg/L. In addition, the penetration rate of polysulfone was 20%, and the film peel strength was 0.51 N/15 mm.

When core:sheath=90:10, the weight per unit area is 70g/㎡, the thickness is 0.10㎜, the density is 0.70g/㎤, the arithmetic average roughness of the surface is 12㎛, the contact angle is 62°, and the TOC amount is 1.2㎎/㎡. It was L. Additionally, the penetration rate of polysulfone was 17% and the film peel strength was 0.56N/15mm.

When core:sheath=60:40, the weight per unit area is 70g/㎡, the thickness is 0.04㎜, the density is 1.75g/㎤, the arithmetic average roughness of the surface is 12㎛, the contact angle is 63°, and the TOC amount is 2.5㎎/㎡. It was L. Additionally, the penetration rate of polysulfone was 12% and the film peel strength was 0.53 N/15 mm.

When core:sheath=50:50, the weight per unit area is 70g/㎡, the thickness is 0.03㎜, the density is 2.33g/㎤, the arithmetic average roughness of the surface is 12㎛, the contact angle is 62°, and the TOC amount is 3.0㎎/㎡. It was L. Additionally, the penetration rate of polysulfone was 8% and the film peel strength was 0.42N/15mm. The results are shown in Table 3.

[Example 27]

Polyethylene terephthalate (PET) with a melting point of 255°C and 0.3% by mass of titanium oxide was used as a core component, an isophthalic acid component of 9.5mol% relative to the total acid component, and PEG with a number average molecular weight of 7000 (Sanyo Kasei Kogyo Approved) Copolymerized polyethylene terephthalate (PET/I-PEG-) containing 8% by mass of PEG6000S (manufactured by Shiki Kaisha) and 5mol% of sodium 5-sulfoisophthalate (SSIA), with a melting point of 230°C and 0.2% by mass of titanium oxide. SSIA) was used as the cis component in the same manner as in Example 1, and the single yarn fineness of the constituent filament whose entire surface was covered with polyethylene terephthalate containing components derived from polyethylene glycol and sodium 5-sulfoisophthalate was 1.9. A spunbond nonwoven fabric with dtex, an average single fiber diameter of 14㎛, and a weight per unit area of 35g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbonded nonwoven fabric laminate was manufactured to have a weight per unit area of 70g/m2, a thickness of 0.09mm, a density of 0.78g/cm3, and an arithmetic mean surface roughness of 12㎛, and the spunbonded nonwoven fabric laminate was manufactured. got it The contact angle of the obtained spunbond nonwoven fabric laminate was 56°, and the TOC amount was 2.2 mg/L. Additionally, the penetration rate of polysulfone was 8% and the film peel strength was 0.68N/15mm. The results are shown in Table 4.

[Example 28]

Polyethylene terephthalate (PET) with a melting point of 255°C and 0.3% by mass of titanium oxide was used as a core component, an isophthalic acid component of 9.5mol% relative to the total acid component, and PEG with a number average molecular weight of 20,000 (Sanyo Kasei Kogyo Co., Ltd.) A copolymerized polyethylene terephthalate (PET/I-PEG- SSIA) was used as the cis component in the same manner as in Example 1, and the single yarn fineness of the constituent filament whose entire surface was covered with polyethylene terephthalate containing polyethylene glycol and sodium 5-sulfoisophthalate (SSIA) was 1.9. A spunbond nonwoven fabric with dtex, an average single fiber diameter of 14㎛, and a weight per unit area of 35g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbond nonwoven fabric laminate had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 11 μm, a contact angle of 35°, and a TOC amount of 2.5 mg/L. Additionally, the penetration rate of polysulfone was 11% and the film peel strength was 1.15 N/15 mm. The results are shown in Table 4.

[Example 29-31]

Polyethylene terephthalate (PET) with a melting point of 255°C and containing 0.3% by mass of titanium oxide is used as a core component, and 50% by mass of PEG (PEG6000S manufactured by Sanyo Kasei Kogyo Co., Ltd.) with a number average molecular weight of 7000 is included, and the melting point is Copolymerized polybutylene terephthalate (PBT-PEG) containing 0.2% by mass of titanium oxide at 220°C is mixed with polybutylene terephthalate (PBT) with a melting point of 220°C and containing 0.2% by mass of titanium oxide, and PEG was carried out in the same manner as in Example 1 except that 2% by mass, 8% by mass, and 14% by mass of copolymerized polybutylene terephthalate (PBT-PEG) was used as the cis component, and polybutylene containing polyethylene glycol was used. A spunbond nonwoven fabric whose entire surface was covered with terephthalate had a single yarn fineness of 1.9dtex, an average single fiber diameter of 14㎛, and a weight per unit area of 35g/m2 was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbond nonwoven laminate of Example 29 had a weight per unit area of 70 g/m2, a thickness of 0.10 mm, a density of 0.70 g/cm3, an arithmetic mean surface roughness of 11 ㎛, a contact angle of 65°, and a TOC amount of 0.5 mg. It was /L. Additionally, the penetration rate of polysulfone was 9% and the film peel strength was 0.69 N/15 mm.

Example 30 had a weight per unit area of 70 g/m2, a thickness of 0.10 mm, a density of 0.70 g/cm3, an arithmetic mean surface roughness of 9 μm, a contact angle of 60°, and a TOC amount of 1.0 mg/L. Additionally, the penetration rate of polysulfone was 11% and the film peel strength was 0.90 N/15 mm.

Example 31 had a weight per unit area of 70 g/m2, a thickness of 0.10 mm, a density of 0.70 g/cm3, an arithmetic average roughness of the surface of 8 μm, a contact angle of 20°, and a TOC amount of 1.7 mg/L. In addition, the penetration rate of polysulfone was 20%, and the film peel strength was 1.80 N/15 mm. The results are shown in Table 4.

[Example 32-34]

Polybutylene terephthalate (PBT), which has a melting point of 220°C and contains 0.3% by mass of titanium oxide, is used as a core component, and 50% by mass of PEG (PEG6000S, manufactured by Sanyo Chemical Industry Co., Ltd.) with a number average molecular weight of 7000 is copolymerized. , copolymerized polybutylene terephthalate (PBT-PEG), which has a melting point of 220°C and contains 0.2% by mass of titanium oxide, and copolymerized polybutylene terephthalate (PBT/I), which is a copolymerized isophthalic component, are mixed, and the isophthalic component amount is mixed. Copolymerized polybutylene terephthalate (PBT/I-PEG) copolymerized with 11.5 mol%, melting point of 200°C, 0.2 mass% titanium oxide, and 2 mass%, 8 mass%, and 14 mass% PEG was used as the cis component. Other than that, the same method as Example 1 was carried out, and the entire surface of the constituent filament covered with polybutylene terephthalate containing polyethylene glycol had a single yarn fineness of 1.9 dtex, an average single fiber diameter of 14 ㎛, and a weight per unit area of 35 g/unit. ㎡ of spunbond nonwoven fabric was manufactured.

Two sheets of the obtained spunbonded nonwoven fabric were stacked, and laminated processing was performed in the same manner as in Example 1, to obtain a spunbonded nonwoven fabric laminate. The obtained spunbond nonwoven laminate of Example 32 had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 10 μm, a contact angle of 64°, and a TOC amount of 0.6 mg. It was /L. Additionally, the penetration rate of polysulfone was 10%, and the film peel strength was 0.73 N/15 mm.

Example 33 had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 8 μm, a contact angle of 59°, and a TOC amount of 1.1 mg/L. Additionally, the penetration rate of polysulfone was 13% and the film peel strength was 1.00N/15mm.

Example 34 had a weight per unit area of 70 g/m2, a thickness of 0.09 mm, a density of 0.78 g/cm3, an arithmetic mean surface roughness of 7 μm, a contact angle of 21°, and a TOC amount of 1.7 mg/L. In addition, the penetration rate of polysulfone was 21%, and the film peel strength was 1.98 N/15 mm. The results are shown in Table 4.

[Comparative Example 1-3]

A spunbond nonwoven fabric was obtained in the same manner as in Example 1, except that the amount of polyethylene glycol copolymerization with a number average molecular weight of 20,000 used in Example 1 was changed as shown in Table 5.

Since the spunbond nonwoven fabric obtained in Comparative Example 1 did not copolymerize polyethylene glycol, the nonwoven fabric surface was rough, the contact angle did not decrease, and almost no penetration into the polysulfone nonwoven fabric was observed. In addition, the spunbond nonwoven fabric obtained in Comparative Example 2 had a small amount of polyethylene glycol copolymerization, and the surface roughness and contact angle were lower than those of Comparative Example 1, but the penetration rate of polysulfone was insufficient. In addition, the spunbond nonwoven fabric obtained in Comparative Example 3 has poor melt moldability due to the excessive amount of copolymerization of polyethylene glycol, frequent yarn breakage due to tension during composite spinning with the core component, and polysulfone due to an increase in density. The permeability became insufficient and high membrane peel strength could not be obtained. In addition, due to the generation of decomposition products and an increase in unreacted PEG, the amount of low molecular weight components increased and the amount of TOC also increased.

[Comparative Examples 4, 5]

A spunbond nonwoven fabric was obtained in the same manner as in Example 3, except that the copolymerization amount of the isophthalic acid component used in Example 3 was changed as shown in Table 5.

In the spunbond nonwoven fabric obtained in Comparative Example 4, the melting point of the cis component decreased due to the excessive copolymerization amount of the isophthalic acid component, and a melting point difference with the core component occurred, resulting in a decrease in radioactivity due to decomposition of the cis component. As radioactivity decreased, the amount of low-molecular-weight components increased due to the generation of decomposition products, and the amount of TOC also increased. In addition, due to the lower melting point of the cis component, excessive fusion of the fibers occurred during heat compression, and the increase in density caused the penetration rate of polysulfone to become insufficient, the adhesiveness of the separator decreased, and high membrane peel strength could not be obtained. .

The spunbond nonwoven fabric obtained in Comparative Example 5 had a small amount of copolymerization of the isophthalic acid component and a high melting point of the cis component, so fusion in thermal compression was insufficient, surface roughness increased, and surface smoothness decreased. In addition, because the density was low, the permeability of polysulfone was obtained, but the high membrane peel strength of polysulfone could not be obtained due to its low strength as a separator support. Additionally, the thickness of the nonwoven fabric increased and filtration performance deteriorated.

[Comparative Example 6]

A spunbond nonwoven fabric was obtained in the same manner as in Example 3 except that the core component used in Example 3 was polybutylene terephthalate (PBT) with a melting point of 220°C and 0.3% by mass of titanium oxide.

In the spunbond nonwoven fabric obtained in Comparative Example 6, since the melting point of the core component was lower than that of the sheath component, the core component was fused together with the sheath component during thermal compression, and the strength as a separator support became insufficient. Additionally, as the density increased, the penetration rate of polysulfone also became insufficient and high film peel strength could not be obtained.

[Comparative Example 7]

A spunbond nonwoven fabric was obtained in the same manner as in Example 3, except that the same copolyester as the cis component used in Example 3 was used in a spinneret for single components to obtain a fiber web of single component fibers.

Since the spunbond nonwoven fabric obtained in Comparative Example 7 is a single-component fiber, the mechanical strength to withstand high pressure as a separator support is insufficient, and the penetration rate of polysulfone is insufficient because the density increases due to fusion during heat compression. and high membrane peeling strength could not be obtained. Additionally, the amount of TOC also increased with the increase in unreacted PEG.

[Comparative Example 8-10]

A spunbond nonwoven fabric was obtained in the same manner as in Example 18, except that the copolymerization amount of sodium 5-sulfoisophthalate used in Example 18 was changed as shown in Table 6.

Since the spunbond nonwoven fabric obtained in Comparative Example 8 did not copolymerize sodium 5-sulfoisophthalate, the contact angle did not decrease and polysulfone did not penetrate into the nonwoven fabric. In addition, the spunbond nonwoven fabric obtained in Comparative Example 9 contained a small amount of sodium 5-sulfoisophthalate, and the contact angle was lower than that of Comparative Example 8, but the penetration rate of polysulfone was insufficient. In addition, the spunbond nonwoven fabric obtained in Comparative Example 10 has poor melt moldability due to the excessive copolymerization amount of sodium 5-sulfoisophthalate, frequent yarn breaks during composite spinning with the core component, and an increase in density. As a result, the permeability of polysulfone became insufficient and high film peel strength could not be obtained. In addition, the amount of low molecular weight components increased due to the generation of decomposition products, and the amount of TOC also increased.

[Comparative Examples 11, 12]

A spunbond nonwoven fabric was obtained in the same manner as in Example 19, except that the copolymerization amount of isophthalic acid used in Example 19 was changed as shown in Table 6.

In the spunbond nonwoven fabric obtained in Comparative Example 11, the melting point of the cis component decreased due to the excessive copolymerization amount of isophthalic acid, and a melting point difference with the core component occurred, resulting in decomposition of the cis component and lowering the radioactivity. As radioactivity decreased, the amount of low-molecular-weight components increased due to the generation of decomposition products, and the amount of TOC also increased. In addition, due to the lower melting point of the cis component, excessive fusion of the fibers occurred during heat compression, and the increase in density caused the penetration rate of polysulfone to become insufficient, the adhesiveness of the separator decreased, and high membrane peel strength could not be obtained. . In the spunbond nonwoven fabric obtained in Comparative Example 12, the amount of isophthalic acid copolymerization was small and the melting point of the cis component was high, so fusion through heat compression became insufficient. In addition, because the density was low, the permeability of polysulfone was obtained, but the high membrane peel strength of polysulfone could not be obtained due to its low strength as a separator support. Additionally, the thickness of the nonwoven fabric increased, resulting in a decrease in filtration performance.

[Comparative Example 13]

A spunbond nonwoven fabric was obtained in the same manner as in Example 19, except that polybutylene terephthalate with a melting point of 220°C and 0.3% by weight of titanium oxide was used as the core component used in Example 19.

In the spunbond nonwoven fabric obtained in Comparative Example 13, since the melting point of the core component was lower than that of the sheath component, the core component was fused together with the sheath component during thermal compression, resulting in insufficient strength as a separator support. Additionally, as the density increased, the penetration rate of polysulfone also became insufficient and high film peel strength could not be obtained.

Claims (9)

It is a spunbond nonwoven fabric containing core sheath-type composite fibers in which the core component is polyester and the sheath component is copolyester,
The melting point of the cis component is [(melting point of core component) -45]°C or more and [(melting point of core component)-15]°C or less,
The copolymerization component of the cis component is
Polyethylene glycol with a copolymerization amount of 2% by mass or more and 15% by mass or less,
or/and
It is an isophthalic acid component containing a metal sulfonate group in a copolymerization amount of 2.5 mol% or more and 7.5 mol% or less relative to the total acid component,
The contact angle with water on the surface of the spunbond nonwoven fabric is 0° or more and 80° or less,
Spunbond nonwoven fabric. The spunbond nonwoven fabric according to claim 1, wherein the cis component is a copolymerized polyester obtained by copolymerizing 2% by mass or more and 15% by mass or less of polyethylene glycol, and the contact angle with water on the surface of the spunbond nonwoven fabric is 5° or more and 80° or less. The spunbond nonwoven fabric according to claim 1 or 2, wherein the polyethylene glycol molecular weight of the cis component is 1,000 to 35,000. The spunbonded nonwoven fabric according to any one of claims 1 to 3, wherein the arithmetic mean roughness of the surface of the spunbonded nonwoven fabric is 0.1 μm or more and 10 μm or less. The spunbond nonwoven fabric according to any one of claims 1 to 4, wherein the composite mass ratio of the core component and the sheath component of the core sheath type composite fiber is 95:5 to 50:50. The method of claim 1, wherein the cis component is a copolymerized polyester obtained by copolymerizing an isophthalic acid component containing a metal sulfonate group in an amount of 2.5 mol% or more and 7.5 mol% or less relative to the total acid component, and the contact angle with water on the surface of the spunbond nonwoven fabric is Spunbond nonwoven fabric with an angle greater than 0° and less than 70°. The spunbonded nonwoven fabric according to claim 1 or 6, wherein the spunbonded nonwoven fabric has a density of 0.5 g/cm3 to 1.8 g/cm3. The spunbond nonwoven fabric according to claim 6 or 7, wherein the composite mass ratio of the core component and the sheath component of the core sheath type composite fiber is 90:10 to 60:40. A separator comprising the spunbond nonwoven fabric according to any one of claims 1 to 8 and a polymer component as components,
The polymer component is at least one selected from the group consisting of polysulfone, polyether sulfone, polyaryl ether sulfone, polyimide, polyvinylidene fluoride, and cellulose acetate, and the penetration rate of the polymer component into the spunbond nonwoven fabric is 5%. Separator, not more than 70%.