Resin composition for hollow fiber element tube sheets, hollow fiber element, separation membrane module, and method for producing dehydrated organic compounds

Abstract

To provide a hollow fiber element that offers excellent durability under high temperatures, particularly under high-temperature and high-pressure environments with organic vapor, and that can improve airtightness in separation membrane modules. [Solution] The present invention provides a resin composition for hollow fiber element tube sheets comprising an epoxy composition and a curing agent, wherein the following fracture strength retention rate, measured in the state of a 0.2 mm thick film-like cured product, is 75% or more. Breaking strength retention rate (%) = B1 / B0 × 100 B1: Breaking strength (MPa) at 23°C after immersion in ethanol at 130°C for 120 hours. B0: Breaking strength (MPa) at 23°C before immersion in ethanol.

Description

[Technical Field]

[0001] The present invention relates to a resin composition for a tube sheet in a hollow fiber element in which a bundle of fibers made of a number of hollow fiber membranes having selective permeability is integrally fixed to the tube sheet, and to the hollow fiber element itself. [Background technology]

[0002] Hollow fiber type separation membrane modules have the advantage of a large membrane area per unit volume, as well as superior pressure resistance and self-supporting properties, making them industrially advantageous and widely used.

[0003] In hollow fiber separation membrane modules, generally, at least one end of a bundle of fibers consisting of numerous hollow fiber membranes with selective permeability is fixed and bound by a tubular sheet formed from a cured material such as an epoxy composition.

[0004] Patent Document 1 describes a hollow fiber element for organic vapor separation in which the hardened material, which is a hollow fiber element tube sheet, has a glass transition temperature of 160°C or higher, a minimum elongation at break of 7.0% or higher, and an elution rate of less than 5%. Furthermore, Patent Document 1 describes a hollow fiber element that has sufficient durability to maintain airtightness between the internal and external spaces of the hollow fiber membrane even when used under high temperature and high pressure organic vapor. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] International Publication No. 2010 / 101140 [Overview of the project] [Problems that the invention aims to solve]

[0006] However, the inventor has found that there is still room for improvement in terms of durability such as prevention of elution and cracking under high temperature, especially under organic vapor in a high temperature and high pressure environment, when the resin composition described in Patent Document 1 is made into a cured product.

Means for Solving the Problems

[0007] The present invention provides the following. 〔1〕 A resin composition for a hollow fiber element tube sheet, comprising an epoxy composition and a curing agent, wherein the following fracture strength retention rate R1 measured in the state of a film-shaped cured product with a thickness of 0.2 mm is 75% or more. A resin composition for a hollow fiber element tube sheet. Fracture strength retention rate R1 (%) = B1 / B0 × 100 B1: Fracture strength (MPa) at 23 ° C after immersion in ethanol at 130 ° C for 120 hours B0: Fracture strength (MPa) at 23 ° C before immersion in ethanol 〔2〕 The resin composition for a hollow fiber element tube sheet according to 〔1〕, wherein the alcohol elution rate when immersed in ethanol at 130 ° C for 120 hours, measured in the state of a film-shaped cured product with a thickness of 0.2 mm, is 2% or less. 〔3〕 The resin composition for a hollow fiber element tube sheet according to 〔1〕 or 〔2〕, wherein the fracture strength B0 at 23 ° C, measured in the state of a film-shaped cured product with a thickness of 0.2 mm, is 30 MPa or more. 〔4〕 The epoxy composition contains 20 to 90% by mass of an epoxy compound (a1) having a ring structure with an epoxy equivalent of 110 or less and 10 to 60% by mass of an epoxy compound (a2) having a ring structure with an epoxy equivalent of 150 or more and 500 or less. The resin composition for a hollow fiber element tube sheet according to any one of 〔1〕 to 〔3〕. 〔5〕 The epoxy compound (a1) is an epoxy compound having three or more epoxy groups on one ring structure, and the epoxy compound (a2) is a bisphenol A type epoxy compound. The resin composition for a hollow fiber element tube sheet according to 〔4〕. 〔6〕 The curing agent is an amine compound having the structure of the following formula (1), the resin composition for hollow fiber element tube sheets according to any one of [1] to [5]. [ka] (In the formula, A 1 (This is a divalent group represented by any of the following formulas (2-1), (2-2), (2-3), (2-4), and (2-5).) [ka] (In the formula, A 2 , A 3 and A 4 These are, independently, divalent organic groups with 1 to 18 carbon atoms. [7] A 1 The resin composition for hollow fiber element tube sheets according to [6], wherein is a divalent group represented by any of the above formulas (2-1), (2-2), and (2-3). [8] A hollow fiber element in which at least one end of a bundle of multiple hollow fiber membranes is fixed and bound by a tube sheet formed of a cured product of a resin composition for hollow fiber element tube sheets described in any one of items [1] to [7]. [9] A separation membrane module in which the hollow fiber elements described in [8] are housed in a pressure vessel.

[10] A gas separation system having the separation membrane module described in [9].

[11] A method for producing a dehydrated organic compound using the gas separation system described in

[10] .

[12] A hollow fiber membrane element for a separation membrane module configuration, wherein at least one end of a plurality of hollow fiber membranes is fixed and bonded by a tubular sheet formed from a cured epoxy composition, The cured material is a hollow fiber element, measured in a 0.2 mm thick film form, with a fracture strength retention rate of 75% or more. Breaking strength retention rate R1 (%) = B1 / B0 × 100 B1: Breaking strength (MPa) at 23°C after immersion in ethanol at 130°C for 120 hours. B0: Breaking strength (MPa) at 23°C before immersion in ethanol. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition for hollow fiber element tube sheets, hollow fiber elements, and separation membrane modules that exhibit excellent durability, such as prevention of elution and cracking, under high temperatures, particularly in the presence of organic vapors in high-temperature and high-pressure environments. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a cross-sectional view showing the structure of one embodiment of the separation membrane module of the present invention. [Figure 2] Figure 2 is a schematic diagram showing an example of the hollow fiber element manufacturing method of the present invention. [Figure 3] Figure 3 is a schematic diagram showing the cracking tests for the examples and comparative examples. [Modes for carrying out the invention]

[0010] Preferred embodiments of the present invention will be described below. The following describes in detail the resin composition for hollow fiber element tube sheets of the present invention, the hollow fiber element, the separation membrane module, and a method for producing a dehydrated organic compound using the separation membrane module.

[0011] <Resin composition for hollow fiber element tube sheets, hollow fiber element> In the present invention, a hollow fiber element is a bundle of hollow fibers, each consisting of a number of hollow fiber membranes having at least selective permeability, to which at least one end is fixed and bound by a tube sheet formed from a cured resin composition for hollow fiber element tube sheets. The fixing and binding are performed while maintaining the open ends of the hollow fibers.

[0012] Figure 1 is a schematic cross-sectional view of an example of a separation membrane module using a hollow fiber element according to this embodiment. The separation membrane module shown in Figure 1 is used for gas separation. The pressure vessel 40 in the separation membrane module 10 shown in Figure 1 has a cylindrical body with both ends open and two lids that close the openings at both ends. The outer frame of the pressure vessel 40 has a mixed gas inlet 38, a carrier gas inlet 39, a permeable gas outlet 42, and a non-permeable gas outlet 41. A bundle of threads 30, formed by bundling together a number of hollow fiber membranes 20 having selective permeability, is built into the pressure vessel 40 as a hollow fiber element in the following manner. That is, the bundle of threads 30 is fixed at the end on the permeable gas outlet 42 side in the figure by a first tube sheet 50a formed from a cured product of the resin composition for hollow fiber element tube sheets, and at the end on the non-permeable gas outlet 41 side in the figure by a second tube sheet 50b also formed from a cured product of the resin composition for hollow fiber element tube sheets, thereby forming a hollow fiber element as a whole. In this hollow fiber element, each hollow fiber membrane 20 forming the hollow fiber bundle 30 penetrates the tube sheets 50b and 50a and is fixed in an open state. In the separation membrane module 10 shown in Figure 1, a mixed gas is introduced from the mixed gas inlet 38, components that permeate through the hollow fiber membrane 20 are discharged from the permeate gas outlet 42, and components that do not permeate are discharged from the non-permeate gas outlet 41.

[0013] As mentioned above, conventional resin compositions for hollow fiber element tube sheets had room for improvement in durability, particularly in preventing leaching and cracking when used under high-temperature conditions, especially under high-temperature, high-pressure, and organic vapor conditions, after curing. However, the inventors have found a resin composition for hollow fiber element tube sheets that is more durable under these conditions than conventional compositions by satisfying specific parameters. Specifically, the resin composition for hollow fiber element tube sheets of the present invention has a fracture strength retention rate of 75% or more, measured in the form of a 0.2 mm thick film-like cured product, more preferably 80% or more, particularly preferably 85% or more, and particularly preferably 90% or more. Breaking strength retention rate R1 (%) = B1 / B0 × 100 B1: Breaking strength (MPa) at 23°C after immersion in ethanol at 130°C for 120 hours. B0: Breaking strength at 23°C under standard conditions (MPa) (breaking strength before immersion in ethanol)

[0014] When the resin composition for hollow fiber element tube sheets of the present invention, having the aforementioned fracture strength retention rate, is cured to form a tube sheet, the tube sheet becomes less susceptible to elution by organic compounds such as ethanol, and also exhibits excellent toughness, making it less prone to cracking even when exposed to high temperature and high pressure, particularly under organic vapors such as ethanol, and then dried.

[0015] The fracture strength retention ratio R1 of the resin composition for hollow fiber element tube sheets of the present invention may be greater than 100% if the decrease in elastic modulus is small and the elongation at fracture improves after ethanol immersion. A larger R1 tends to reduce cracking of the tube sheet, but it is usually 120% or less.

[0016] The cured product of the resin composition for hollow fiber element tube sheets of the present invention preferably has a breaking strength B1 of 30 MPa or more, more preferably 35 MPa or more, more preferably 40 MPa or more, and even more preferably 45 MPa or more. Furthermore, while a higher breaking strength B1 value tends to reduce tube sheet cracking in the cured product of the resin composition for hollow fiber element tube sheets, it is usually 60 MPa or less.

[0017] The cured product of the resin composition for hollow fiber element tube sheets of the present invention has excellent toughness, and its breaking strength B0 is preferably 30 MPa or higher, more preferably 35 MPa or higher, and even more preferably 40 MPa or higher. Furthermore, the cured product of the resin composition for hollow fiber element tube sheets tends to reduce tube sheet cracking as the breaking strength B0 value increases, but it is usually 60 MPa or lower.

[0018] The cured product of the resin composition for hollow fiber element tube sheets of the present invention preferably has an elution rate of 2% or less, more preferably 1.5% or less, even more preferably 1% or less, and particularly preferably 0.5% or less. The elution rate is the percentage of weight loss of a cured resin composition for hollow fiber element tube sheets when it is immersed in a high-temperature organic compound. In this specification, the elution rate is defined as the percentage of weight loss when ethanol at 130°C is selected as the high-temperature organic compound. The elution rate can be specifically measured by the method described in the examples below. Cured materials with a low elution rate exhibit excellent durability under high temperature, high pressure, and in the presence of organic vapors. The aforementioned elution rate can be calculated by multiplying the value obtained by dividing the change in dry weight (weight loss) before and after immersion in ethanol at 130°C for 120 hours using a sample with a thickness of approximately 0.2 mm, a length of 40 mm, and a width of 6 mm by the weight of the sample before immersion in ethanol, by 100.

[0019] The resin composition for hollow fiber element tube sheets of the present invention is preferably excellent in terms of strength and durability at high temperatures, and it is preferable that the following fracture strength retention rate R2 is high when the resin composition for hollow fiber element tube sheets is measured in the form of a 0.2 mm thick film-like cured product. Specifically, it is preferable that the cured product of the resin composition for hollow fiber element tube sheets of the present invention has a fracture strength retention rate R2 of 55% or more, more preferably 60% or more, particularly preferably 65% ​​or more, and particularly preferably 70% or more. Breaking strength maintenance rate R2(%)=B2 / B0×100 B2: Breaking strength (MPa) at 23°C after being held at 150°C for 10 minutes under normal atmospheric pressure. B0: Breaking strength at 23°C under standard conditions (MPa) (Breaking strength before holding at 150°C for 10 minutes)

[0020] The resin composition for hollow fiber element tube sheets having the aforementioned fracture strength retention ratio R2 exhibits excellent high-temperature durability even in the absence of organic vapors when cured, and can therefore be used for applications other than organic vapor separation. Examples of applications other than organic vapor separation include the separation of nitrogen and oxygen from air, the separation of carbon dioxide from mixed gases such as natural gas and biogas, dehumidification or humidification of air, hydrogen and helium separation from various mixed gases, seawater desalination and ultrapure water production, and removal of bacteria and viruses from water.

[0021] In the resin composition for hollow fiber element tube sheets of the present invention, a higher fracture strength retention rate R2 is preferable, but it is usually 100% or less.

[0022] The cured product of the resin composition for hollow fiber element tube sheets of the present invention preferably has a breaking strength B2 of 20 MPa or more, more preferably 23 MPa or more, even more preferably 26 MPa or more, and still more preferably 29 MPa or more. Furthermore, while a higher breaking strength B2 is preferable for the cured product of the resin composition for hollow fiber element tube sheets, it is usually 50 MPa or less.

[0023] The breaking strength can be measured by a tensile test. A tensile test is performed under the conditions of a tensile speed of 2 mm / min and a chuck distance of 20 mm, and the value obtained by dividing the maximum load by the cross-sectional area of ​​the sample before the test (maximum nominal stress) is defined as the breaking strength in this specification. The breaking strength sample may be obtained by curing the resin composition for hollow fiber element tube sheets, or it may be cut from the tube sheet of a separation membrane module.

[0024] For a resin composition for hollow fiber element tube sheets, the following conditions can be used for heat treatment to obtain a 0.2 mm thick film-like cured product for tensile testing: For example, the resin composition before curing can be heated at 60°C for 24 hours (15 hours) for primary curing, then the temperature is increased to 90°C at a rate of 0.25°C / min, maintained at 90°C for 2 hours, then the temperature is increased to 120°C at a rate of 0.25°C / min, maintained at 120°C for 2 hours, then the temperature is increased to 150°C at a rate of 0.25°C / min, maintained at 150°C for 2 hours, and finally the temperature is increased to 180°C at a rate of 0.25°C / min for 4 hours for post-curing. An atmospheric environment can be used during the heat treatment.

[0025] The resin composition for hollow fiber element tube sheets of the present invention contains an epoxy composition and a curing agent. The epoxy composition is a composition containing one or more compounds having two or more epoxy groups (epoxy compounds). The curing agent is a compound that can cure the epoxy composition. The following terms are explained below in relation to the resin compositions for hollow fiber element tube sheets. The term "ring structure" as used herein does not include epoxy rings. Preferably, the "ring structure" as used herein is an aromatic ring. In this specification, the number of "ring structures" is counted as 1 for both a single ring and a single fused ring. The number of "rings" is counted as 1 for a single ring, and for a single fused ring, the number of rings constituting that fused ring is counted. For example, "biphenyl" has two ring structures and two rings. "Naphthyl" has one ring structure and two rings. "Binaphthyl" has two ring structures and four rings. Furthermore, the "number of constituent atoms of the linking group" refers to the number of atoms that connect the rings in the shortest possible way, in the case of a linking group that connects rings to rings. For biphenyl linking groups, this number is 0, and for bisphenol A linking groups, it is 1. In the case of a linking group that connects a ring to an epoxy group, this number refers to the number of atoms that connect the ring to the epoxy group in the shortest possible way, in the case of glycidylphenyl ether, it is 2. Furthermore, in this specification, when a linking group is a combination of an alkylene group and other divalent groups (such as -O-), the other divalent groups shall not be adjacent to each other. Furthermore, unless otherwise specified in this specification, the following linking groups and ring structures include those in which the hydrogen atoms in the constituting groups (e.g., alkylene groups) are substituted with substituents. Examples of such substituents include halogen atoms, hydroxyl groups, alkyl groups, and alkyl halides. In this specification, examples of halogen atoms include fluorine, chlorine, bromine, and iodine. In this specification, hydrocarbon groups include, as monovalent groups, alkyl groups, alkenyl groups, cycloalkyl groups, cycloalkylalkyl groups, aryl groups, and arylalkyl groups. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl groups, butyl, isobutyl, tertiary butyl, amyl, isoamyl, tertiary amyl, hexyl, isohexyl, and octyl. Examples of cycloalkyl groups include cyclohexyl. Examples of cycloalkylalkyl groups include cyclohexylethyl. Examples of alkenyl groups include vinyl, 2-propenyl, 3-butenyl, 2-butenyl, 4-pentenyl, 3-pentenyl, 2-hexenyl, 3-hexenyl, 5-hexenyl, 2-heptenyl, 3-heptenyl, and 4-heptenyl. Examples of aryl groups include phenyl, methylphenyl, dimethylphenyl, ethylphenyl, and naphthyl. Examples of arylalkyl groups include benzyl and phenethyl. Furthermore, if the hydrocarbon group is divalent or higher, it can be a group corresponding to the various monovalent hydrocarbon groups mentioned above. For example, alkylene groups include linear and branched groups. Examples of linear alkylene groups include methylene, ethylene, n-propylene, n-butylene, and hexylene groups, while examples of branched alkylene groups include isopropylene, isobutylene, and 2-methylpropylene groups. For example, an arylene group is a group obtained by removing one hydrogen atom from the various aryl groups mentioned above.

[0026] In the resin composition for hollow fiber element tube sheets of the present invention, it is preferable that the epoxy composition contains 20 to 90% by mass of an epoxy compound (a1) having a ring structure with an epoxy equivalent of 110 or less, and 10 to 60% by mass of an epoxy compound (a2) having a ring structure with an epoxy equivalent of 150 to 500. By adopting the above composition, which combines two epoxy compounds having a rigid ring structure and different crosslinking properties in specific amounts, the resin composition for hollow fiber element tube sheets makes it easier to obtain a cured product having the above-mentioned fracture strength retention rate. The epoxy equivalent can be measured by a method compliant with JIS K7236:2001.

[0027] The ring structure in epoxy compound (a1) is a ring with 5 or more members, and can be a monoring or a fused ring. From the viewpoint of the cured resin composition having excellent durability at high temperatures, especially under high temperature and pressure conditions and in the presence of organic vapor, the number of ring structures in epoxy compound (a1) is preferably 3 or less, more preferably 2 or less, and most preferably 1. Furthermore, if the epoxy compound (a1) has two or more ring structures, it has a structure in which multiple ring structures are linked by a linking group L1. When a structure has multiple ring structures linked by a linking group L1, the linking group L1 can be a single bond, -O-, -S-, or -NR. 11 Examples include -, -CO-, -SO2-, or alkylene groups having 1 to 5 carbon atoms, or combinations thereof. The number of constituent atoms of the linking group L1 that connects the rings is preferably 5 or less, more preferably 3 or less, and particularly preferably 1 or less. 11 This is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, preferably with 5 or fewer carbon atoms, and more preferably with 3 or fewer carbon atoms.

[0028] The ring structure in the epoxy compound (a1) is a ring of 5-membered or more. As the ring structure in the epoxy compound (a1), an aromatic ring is preferable in that the cured product of the resin composition is excellent in durability under high temperatures, particularly under high temperature and high pressure and in the presence of organic vapor. As the aromatic ring, a hydrocarbon aromatic ring in which the atoms constituting the ring structure are carbon and a heteroaromatic ring in which the atoms constituting the ring structure are carbon atoms and heteroatoms are known. Examples of the hydrocarbon aromatic ring include a benzene ring, a naphthalene ring, an anthracene ring, etc. Examples of the heteroaromatic ring include a pyridine ring, a pyrazine ring, a pyrrole ring, a quinoline ring, a quinoxaline ring, a furan ring, a benzofuran ring, a thiophene ring, a benzothiophene ring, an oxazole ring, a thiazole ring, an imidazole ring, a pyrazole ring, an indole ring, a carbazole ring. The ring structure in the epoxy compound (a1) being a hydrocarbon aromatic ring is preferable in that the cured product of the resin composition is further excellent in durability under high temperatures, particularly under high temperature and high pressure and in the presence of organic vapor, more preferably a benzene ring or a naphthalene ring, and particularly preferably a benzene ring.

[0029] The epoxy compound (a1) is preferably an epoxy compound having three or more epoxy groups on one ring structure in that the cured product of the resin composition is further excellent in durability under high temperatures, particularly under high temperature and high pressure and in the presence of organic vapor. Here, having an epoxy group on the ring structure includes not only the case where the epoxy group is directly bonded to the atoms constituting the ring, but also the case where the epoxy group is bonded to the atoms constituting the ring via a linking group L2. Examples of the linking group L2 include -O-, -S-, -NR 12 -, -CO-, -CO-O-, -CO-NR 12 -, -CO-S-, -N<, a carbon atom, an alkylene group having 1 to 7 carbon atoms or a group combining these, and -O-, -NR 12 -, -N<, an alkylene group having 1 to 7 carbon atoms or a group combining these are more preferable, and a group combining -O- and an alkylene group having 1 to 7 carbon atoms, or a group combining -N< and an alkylene group having 1 to 5 carbon atoms is particularly preferable. The number of constituent atoms of the linking group L2 is preferably 5 or less, more preferably 1 to 3, and particularly preferably 2. Here, R 12This is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, with a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms being more preferred.

[0030] The epoxy compound (a1) may have any of the following epoxy group-containing groups: a glycidyl group, an alicyclic epoxy group, etc. However, having a glycidyl group is particularly preferable because it provides superior durability of the cured resin composition at high temperatures, especially under high temperature and pressure conditions and in the presence of organic vapors. The epoxy compound (a1) preferably has a glycidyl ether group and / or a glycidylamino group as the glycidyl group-containing group, and is particularly preferred to have a glycidylamino group. The glycidylamino group is preferably a bifunctional group.

[0031] The epoxy equivalent of epoxy compound (a1) is 110 or less, preferably 108 or less, more preferably 106 or less, even more preferably 104 or less, particularly preferably 102 or less, and even more preferably 100 or less. Furthermore, the epoxy equivalent is preferably 70 or more, more preferably 75 or more, even more preferably 80 or more, even more preferably 85 or more, and particularly preferably 90 or more. By keeping the epoxy equivalent within the above range, the cured product of the resin composition exhibits excellent durability at high temperatures, especially under high temperature and high pressure and in the presence of organic vapor. Although not limited, the molecular weight of epoxy compound (a1) is preferably 180 to 450, more preferably 200 to 400, and particularly preferably 240 to 350.

[0032] Examples of epoxy compounds (a1) include compounds represented by the following formula (3).

[0033] [ka] R represents an alkyl group having 1 to 3 carbon atoms, a fluorinated alkyl group having 1 to 3 carbon atoms, or a hydrogen atom. In this specification, examples of fluorinated alkyl groups having 1 to 3 carbon atoms include trifluoromethyl, trifluoroethyl, pentafluoropropyl, and hexafluoroisopropyl.

[0034] From the viewpoint that the resulting cured product exhibits superior durability under high temperatures, particularly under high temperature and pressure conditions and in the presence of organic vapor, the content of epoxy compound (a1) in the epoxy composition is preferably 20% by mass or more, more preferably 23% by mass or more, even more preferably 25% by mass or more, and even more preferably 28% by mass or more. Also from a similar viewpoint, the content of epoxy compound (a1) in the epoxy composition is preferably 90% by mass or less, more preferably 89% by mass or less, even more preferably 88% by mass or less, and even more preferably 86% by mass or less.

[0035] Since the resulting cured product exhibits superior durability under high temperatures, particularly under high temperature and pressure conditions and in the presence of organic vapor, bisphenol A type epoxy compounds are preferred as epoxy compounds (a2). Examples of bisphenol A type epoxy compounds include those represented by the following formula (4).

[0036] [ka] n represents a number between 0 and 100.

[0037] The epoxy equivalent of epoxy compound (a2) is 150 or more, may be 160 or more, may be 170 or more, and may be 180 or more. The epoxy equivalent of epoxy compound (a2) is 500 or less, preferably 400 or less, more preferably 300 or less, even more preferably 250 or less, and particularly preferably 200 or less.

[0038] From the viewpoint that the cured resin composition exhibits superior durability under high temperatures, particularly under high temperature and pressure conditions and in the presence of organic vapor, the content of epoxy compound (a2) in the epoxy composition is preferably 10% by mass or more, more preferably 13% by mass or more, and even more preferably 15% by mass or more. Also from a similar viewpoint, the content of epoxy compound (a2) in the epoxy composition is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 40% by weight or less, and even more preferably 30% by weight or less.

[0039] Furthermore, the epoxy composition may also contain epoxy compounds other than those exemplified above as epoxy compound (a1) and epoxy compound (a2). Preferably, the epoxy compound is a ring-structured epoxy compound. For example, a ring-structured epoxy compound (a3) ​​with an epoxy equivalent of 105 or more, particularly more than 110 and less than 150, is particularly preferred. The content of epoxy compound (a3) ​​in the epoxy composition is preferably 0 to 60% by mass. In this specification, if epoxy compound (a1) is a compound with one ring, epoxy compound (a2) is preferably a compound with two or more rings, and even if the epoxy equivalent is 110 or less, it can be distinguished from epoxy compound (a1) by having such a number of rings. The amounts of epoxy compounds (a1) and (a3) ​​described herein correspond to this method of distinction.

[0040] In epoxy compound (a3) ​​having a ring structure with an epoxy equivalent of 105 or more, particularly between 110 and 150, the aforementioned ring structure can be an aliphatic ring or an aromatic ring, but an aromatic ring is preferred in terms of superior strength retention effect. Examples of aromatic rings are those listed in epoxy compound (a1). The ring structure in epoxy compound (a3) ​​may be a monoring or a fused ring. Epoxy compound (a3) ​​may have a structure in which the ring structures are linked by a linking group L4. The linking group L4 that connects the rings can be a single bond, -O-, -S-, or -NR. 11Examples include -, -CO-, -SO2-, alkylene groups having 1 to 7 carbon atoms, or groups combining these. The number of constituent atoms of the linking group L4 is preferably 5 or less, more preferably 1 to 3, and particularly preferably 1. The linking group L4 may be an alkylene group, or an alkylene group with -O-, -S-, -NR 11 -, -CO-, CO-NR 11 - or a combination of -CO-S-, -O-, -S-, -NR 11 -, -CO-, or -SO2- are preferred. The number of carbon atoms in the linking group L4 is preferably 12 or less, and particularly preferably 7 or less.

[0041] The ring structure in epoxy compound (a3) ​​is preferably a hydrocarbon aromatic ring, more preferably a benzene ring or a naphthalene ring, and particularly preferably a benzene ring, from the standpoint of excellent strength maintenance. The number of ring structures in epoxy compound (a3) ​​may be one or two or more, but two or more is preferred from the standpoint of excellent strength maintenance, 2 to 4 is preferred, 2 to 3 is more preferred, and 2 is particularly preferred.

[0042] The epoxy compound (a3) ​​is preferably a compound having two or more epoxy groups on one or more ring structures, more preferably a compound having two to three epoxy groups on one or more ring structures, particularly preferably a compound having two epoxy groups on one or more ring structures, and most preferably a compound having two epoxy groups on two or more ring structures. Having epoxy groups on a ring structure includes not only cases where the epoxy groups are directly bonded to the atoms constituting the ring, but also cases where the epoxy groups are bonded to the atoms constituting the ring via a linking group L2. The preferred linking group L2 is the same as for epoxy compound (a1). The epoxy compound (a3) ​​preferably has a glycidyl ether group or a glycidylamino group as a glycidyl group-containing group, and particularly preferably a glycidylamino group. The glycidylamino group is preferably a bifunctional group.

[0043] The epoxy equivalent of epoxy compound (a3) ​​is preferably less than 150, more preferably 140 or less, and even more preferably 130 or less. The epoxy equivalent of epoxy compound (a3) ​​is preferably greater than 110, more preferably 111 or more, and even more preferably 114 or more.

[0044] The molecular weight of epoxy compound (a3) ​​is preferably 1000 or less, and more preferably 600 or less. The molecular weight of epoxy compound (a3) ​​is preferably 50 or more, and more preferably 80 or more.

[0045] Examples of epoxy compounds (a3) ​​include compounds represented by the following formula (5).

[0046] [ka] Ep stands for epoxy group, R ’’ Each independently represents a methylene group or -C(R''')2-, and each independently represents an alkyl group with 1 to 3 carbon atoms, a fluorinated alkyl group with 1 to 3 carbon atoms, or a hydrogen atom. m1, p1, m2, and p2 are each numbers of 1 or 2, and m1+p1=3, m2+p2=3. L5 is a (m1+1) valence group, and L6 is a (m2+1) valence group. The number of constituent atoms of L5 and L6 is preferably 2 or 3. If L5 and L6 are divalent, a group combining a methylene group and -O- is preferred, and if they are trivalent, a group combining a methylene group and -N< is preferred. L5 and L6 are each R ’’ It is preferable to bond to it in a meta or para position.

[0047] From the standpoint of further improving the toughness of the cured product and its durability under high temperature and high pressure conditions and in the presence of organic vapor, the content of epoxy compound (a3) ​​in the epoxy composition is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 95% by mass or more.

[0048] Examples of epoxy compounds (a1) include triglycidyl derivatives such as 4-amino-phenol, 3-aminophenol, 2-aminophenol, 4-amino-m-cresol, 4-amino-o-cresol, 2-ethyl-4-aminophenol, and 3-ethyl-4-aminophenol, but triglycidyl 4-aminophenol, which is a triglycidyl derivative of 4-aminophenol, is preferred. Examples of epoxy compounds (a2) include jER825, jER827, jER828, and jER834 from Mitsubishi Chemical Corporation, EPICLON840 and EPICLON850 from DIC Corporation, YD127 and YD-128 from Nippon Steel Chemical & Material Corporation, and ADEKA Resin EP-4100, EP-4300, EP-4400, EP-4520, and EP4530 from ADEKA Corporation, but jER828 from Mitsubishi Chemical Corporation (a liquid bisphenol A type epoxy compound) is preferred. Examples of epoxy compounds (a3) ​​include tetraglycidyldiaminodiphenylmethane, N,N,N',N'-tetraglycidyl-1,3-benzenedi(methaneamine), N,N,N',N'-tetraglycidyl-1,4-benzenedi(methaneamine), N,N'-(cyclohexane-1,3-diylbismethylene)bis(diglycidylamine), and N,N'-(cyclohexane-1,4-diylbismethylene)bis(diglycidylamine), but jER604 from Mitsubishi Chemical, ELM-434 from Sumitomo Chemical, and TETRAD-X and TETRAD-C from Mitsubishi Gas Chemical are preferred.

[0049] As the curing agent (B), an amine-based curing agent is preferred because it offers high water resistance and easily provides excellent mechanical properties. The amine-based curing agent can be an aromatic amine compound, an aliphatic amine compound, or a combination thereof. Aliphatic amine compounds include alicyclic amine compounds. Aromatic amine compounds are particularly preferred because they easily provide high-temperature durability for the cured product.

[0050] As a curing agent in resin compositions for hollow fiber element tube sheets, it is particularly preferable to use an amine compound having the structure of the following formula (1) because it is easier to obtain an effect of maintaining strength reduction under high temperature, especially under high temperature and high pressure and in the presence of organic vapor, and it is easier to produce cured products with a higher fracture strength retention rate. [ka] (In the formula, A 1 (This is a divalent group represented by any of the following formulas (2-1), (2-2), (2-3), (2-4), and (2-5).) [ka] (In the formula, A 2 , A 3 and A 4 These are, independently, divalent organic groups with 1 to 18 carbon atoms.

[0051] A 2 , A 3 and A 4 Organic groups with 1 to 18 carbon atoms represented by include alkylene groups, arylene groups, and combinations of alkylene and arylene groups. However, one or more of the methylene groups constituting each of the aforementioned alkylene groups are -O-, -S-, or -NR 13 -, -CO-, -CO-NR 13 -, -NR 13 It may be substituted with -CO-, -CO-S-, or -S-CO-. Note that such substitution of the methylene group is A 2 , A 3 and A 4 It is preferable that this occurs with respect to the methylene group constituting the main chain in the linking group represented by R 13 This is a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, with a hydrogen atom or a hydrocarbon group having 1 to 5 carbon atoms being preferred.

[0052] A 2 , A 3 and A 4Suitable examples of organic groups having 1 to 18 carbon atoms represented by the formulas (6-1) or (6-2) below include alkylene groups having 2 to 18 carbon atoms, or groups represented by the formulas (6-1) or (6-2) below.

[0053] [ka] (In the formula, R 8 , R 10 and R 13 Each of these is independently a hydrocarbon group having 1 to 3 carbon atoms, a halogen atom, or a hydroxyl group, and n8, n10, and n13 are each independently integers from 0 to 4. 12 This is either a directly bonded alkylene group having 1 to 6 carbon atoms, or an alkylene group having 1 to 6 carbon atoms, a phenylene group, or a group having 7 to 10 carbon atoms formed by a combination of an alkylene group and a phenylene group. However, one or more methylene groups in the alkylene group are -O-, -S-, or -NR. 14 -, -CO-, -CO-NR 14 -or-NR 14 It may also be substituted with -CO-. Such substitution of the methylene group is R 12 It is preferable that this occurs with respect to the methylene group constituting the main chain of the linking group represented by R 14 Examples include hydrogen atoms or hydrocarbon groups having 1 to 10 carbon atoms, with hydrogen atoms or hydrocarbon groups having 1 to 5 carbon atoms being preferred.

[0054] Among hardening agents, A 1 However, it is preferable that the divalent group is represented by any of the above formulas (2-1), (2-2), and (2-3) in order that the cured product of the resin composition has excellent toughness and excellent crack prevention and elution prevention effects at high temperatures, especially under high temperature and high pressure in organic vapor, and is a divalent group represented by any of the above formulas (2-1), (2-2), and (2-3), where A in formula (2-3) 2 It is more preferable that the group is represented by formula (6-1) or (6-2), and in particular a divalent group represented by either formula (2-1) or (2-2), with the divalent group represented by formula (2-1) being the most preferred.

[0055] Furthermore, due to its low melting point and ease of handling, if the curing agent is an aromatic amine compound represented by formula (1), then at least one of the two amino groups in formula (1) is a linking group A in the benzene ring to which the amino group is attached. 1 It is preferable that the amino group is bonded at the meta position. One of the two amino groups is the linking group A in the benzene ring to which the amino group is bonded. 1 In contrast, when bonded at the meta position, the other amino group is linked to the linking group A in the benzene ring to which the other amino group is bonded. 1 It is preferable that the bond is located at the meta or para position.

[0056] The active hydrogen equivalent of the curing agent is preferably 150 or less, more preferably 120 or less, even more preferably 110 or less, even more preferably 80 or less, and particularly preferably 60 or less. Furthermore, the active hydrogen equivalent is preferably 20 or more, preferably 30 or more, and particularly preferably 40 or more. The active hydrogen equivalent is the amount of active hydrogen that can react with the epoxy groups of the epoxy composition, and corresponds to the amine equivalent when the curing agent is an amine compound.

[0057] The amount of curing agent (especially aromatic amine compounds) used is preferably about 60% to 140% of the stoichiometric amount calculated from the epoxy equivalent of the epoxy composition. Furthermore, it is preferable that it is blended in a proportion of 80% to 120% of the stoichiometric amount. Within these ranges, the resin composition for hollow fiber element tube sheets hardens sufficiently, making it easier to form strong tube sheets, which is preferable.

[0058] The resin composition for hollow fiber element tube sheets of the present invention may contain components other than the epoxy composition and curing agent. Examples of components other than the epoxy composition and curing agent include resins other than epoxy resins (epoxy compounds), metals, metal oxides, aluminosilicates, and carbon materials. The amount of components other than the epoxy composition and curing agent in the resin composition for hollow fiber element tube sheets may be, for example, 50% by mass or less, or 30% by mass or less.

[0059] Examples of amine compounds having the structure of formula (1) include 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis(4-aminophenoxy)terephthalate, and 1,4-bisN,N'-(4'-aminophenyl)terephthalamide, but 3,4'-diaminodiphenyl ether is preferred.

[0060] The cured product of the resin composition for hollow fiber element tubes of the present invention can be obtained by heat treatment of an uncured resin composition for hollow fiber element tubes containing an epoxy composition and a curing agent.

[0061] As described above, the hollow fiber element of the present invention is characterized in which at least one end of a bundle of fibers consisting of multiple hollow fiber membranes is fixed and bound by a tube sheet formed from a cured product of the resin composition for hollow fiber element tube sheets. Regarding the tube sheet in this hollow fiber element, all of the preferred values ​​for the fracture strength retention rate, fracture strength, and elution rate described above apply.

[0062] The hollow fiber membrane having selective permeability used in the hollow fiber element of the present invention is formed from a material suitable for the target of separation and the separation conditions. For example, it is preferably formed from materials such as elastomers and glassy polymers, exemplified by polybutadiene, polychloroprene, butyl rubber, silicone resin, polyethylene, polypropylene, ethylene-propylene copolymer, polystyrene, poly-4-methyl-1-pentene, polytetrafluoroethylene, polyvinylidene fluoride, tetrafluoroethylene-ethylene copolymer, polychlorotrifluoroethylene, cellulose acetate, polyvinyl chloride, polyvinyl alcohol, polymethyl methacrylate, polyamide, polysulfone, polyethersulfone, polyetheretherketone, polyimide, polyamideimide, polyetherimide, polyphenylene sulfide, polyarylate, and polycarbonate. In particular, hollow fiber membranes made of polyimide are preferred because they have excellent heat resistance, resistance to organic solvents, and permeability, and polyimide containing an aromatic skeleton is preferred, and hollow fiber membranes made of aromatic polyimide are particularly preferred. Here, aromatic polyimide refers to a polyimide in which the portion derived from the acid dianhydride has an aromatic structure, and furthermore, the portion derived from the diamine also contains an aromatic structure.

[0063] The structure of the hollow fiber membrane may be homogeneous or heterogeneous, such as a composite membrane or an asymmetric membrane. An asymmetric membrane made of aromatic polyimide is most suitable because it has excellent selectivity and permeability. A membrane with a film thickness of 20 to 200 μm and an outer diameter of 50 to 1000 μm is preferably used.

[0064] The hollow fiber bundle in this invention is formed by bundling together a large number of hollow fiber membranes having the aforementioned selectivity. Typically, about 100 to 1,000,000 hollow fiber membranes are bundled together. There are no particular restrictions on the shape of the bundled hollow fiber bundle. For example, the bundle may be formed by bundling hollow fiber membranes in a prismatic or plate-like shape, or it may be a tube sheet with a rectangular parallelepiped shape. From the viewpoint of ease of manufacture and pressure resistance of the container, cylindrical bundles of hollow fiber bundles and disc-shaped tube sheets are preferably used. The hollow fibers may be substantially parallel to the axis or at a certain angle, but it is preferable that they are bundled so as to be alternately intersecting at an angle of 5 to 30 degrees with respect to the axial direction.

[0065] In the hollow fiber element of the present invention, the tube sheet may be fixed to both ends of the hollow fiber bundle, or to only one end of the hollow fiber bundle. Furthermore, even in a hollow fiber element in which the tube sheet is fixed to both ends of the hollow fiber bundle, the other end may be closed as long as the opening of the hollow fiber is maintained at one end. In a hollow fiber element in which the tube sheet is fixed to only one end, the other end is configured so that the hollow fiber does not open by means of closing the end of the hollow fiber or folding back the hollow fiber. Preferably, the hollow fiber bundle is configured to be fixed by the tube sheet while maintaining the opening at both ends.

[0066] The hollow fiber element of the present invention preferably has a core tube that has the function of introducing gas to the approximate center of the hollow fiber bundle. The gas introduced to the approximate center of the hollow fiber bundle is preferably a carrier gas. The approximate center of the hollow fiber bundle referred to here is intended to spread the introduced gas throughout the entire hollow fiber, so it is sufficient to achieve this objective, and is not limited to the exact center.

[0067] Next, a preferred method for manufacturing the hollow fiber element of the present invention will be described. A known method is a preferred method for manufacturing the hollow fiber element of the present invention. A bundle of hollow fiber membranes 20 of a predetermined length and number is assembled into a hollow fiber bundle 30. The core tube is removed, or the core tube remains in place approximately in the center of the bundle. The bundle is then placed in a mold 11 (see Figure 2a) for forming a tube sheet at the end. The hollow fiber bundle and a cylindrical container are held substantially vertically with the end facing downwards. A schematic diagram of this state is shown in Figure 2b. A predetermined amount of a resin composition for hollow fiber element tube sheets, before curing, is injected into the mold 11 to form the tube sheet. Hereinafter, the resin composition for hollow fiber element tube sheets will also be simply referred to as the "resin composition." A schematic diagram of the state after the resin composition has been injected is shown in Figure 2c.

[0068] From the standpoint of moldability, the resin composition before curing is preferably liquid at the temperature at which the resin is injected. There are no particular restrictions on the viscosity of the resin composition before curing, but it is preferable that the viscosity at a temperature of 40°C is 0.1 Pa·s or more and less than 100 Pa·s. Here, the viscosity of the resin composition is measured using a rotational viscometer. After injecting the resin composition into the mold 11, the resin composition is heated by maintaining the mold and the hollow fiber bundle at a constant temperature. The temperature at this time is 100°C or less, preferably 30 to 80°C.

[0069] After the resin composition is heated, it is desirable to pre-cur it by heating it at a temperature between 25°C and 110°C until the resin composition loses its fluidity, in order to obtain a good cured resin composition. As a method for pre-curing, it is preferable to slowly heat the resin composition at a heating rate of 0.1°C / min to 10°C / min after the aforementioned heating to 110°C or lower. Subsequently, post-curing is preferable to prevent changes in physical properties during module operation. In this case, it is desirable to heat-treat the resin composition at a temperature above the module's operating temperature, for example, 120°C or higher, more preferably 160°C or higher.

[0070] After the resin composition has been cured, the tube sheet is cut, and the hollow fiber membrane is opened at the ends, thereby creating a hollow fiber element in which the hollow fiber remains open at the ends and is fixed to the tube sheet. In this case, when forming tubular sheets at both ends of a hollow fiber bundle, the procedure described above is used to form a tubular sheet at one end of the hollow fiber bundle, and then the same procedure is used to form a tubular sheet at the other end. Furthermore, when forming a carrier gas guide film 37 (see Figure 1) on a bundle of hollow fiber membranes, for example, a resin film can be wrapped around the hollow fiber membrane and glued to the tube sheet portion of the bundle of hollow fiber membranes, and then the bundle of hollow fiber membranes can be held in the state shown in Figure 2b to form the tube sheet.

[0071] <Separation Membrane Module> The separation membrane module in this invention is a device in which one or more hollow fiber elements of the present invention are housed in a pressure vessel. The separation membrane module of this invention has excellent airtightness due to the durability of the hollow fiber elements of the present invention under high temperatures, particularly under high temperatures and pressures and in the presence of organic vapor. The pressure vessel preferably has at least a mixed gas inlet, a permeable gas outlet, and a non-permeable gas outlet, and may also have a carrier gas inlet. The form of the separation membrane module is not particularly limited and may be a hollow feed type or a shell feed type, and may be a type that uses a carrier gas or a type that does not use a carrier gas. In the hollow feed type, as shown in the configuration of Figure 1, the mixed gas inlet and the non-permeable gas outlet are connected to the internal space of the hollow fiber membrane, and the permeable gas outlet is connected to the external space of the hollow fiber membrane. In this case, the carrier gas inlet is usually also connected to the external space of the hollow fiber membrane. Examples of materials for the pressure vessel include metal, resin, and fiber-reinforced plastic (FRP), and can be appropriately selected depending on the environment of the installation site and the conditions under which it is used. For applications requiring pressure resistance and heat resistance, metal, which combines strength and formability, is preferred, and stainless steel is more preferred. From the viewpoint of improving the pressure resistance of the pressure vessel, the cross-sectional shape of the pressure vessel is preferably elliptical or circular, and circular is more preferred. Within the module, the space leading to the internal space of the hollow fiber membrane and the space leading to the external space of the hollow fiber membrane are separated from each other, maintaining airtightness.

[0072] <Gas Separation System> The gas separation system of the present invention uses at least one separation membrane module of the present invention. Examples of the gas separation system of the present invention include a system in which multiple separation membrane modules of the present invention are arranged in parallel and each separation membrane module shares a mixed gas inlet, a non-permeable gas outlet, a permeable gas outlet, and, if necessary, a carrier gas inlet, and a system in which multiple separation membrane modules of the present invention are connected in series.

[0073] <Gas separation method (method for producing dehydrated organic compounds)> The present invention describes a gas separation method using a gas separation system, particularly a method for producing dehydrated organic compounds. Dehydrated organic compounds are usually produced by separation of water-containing organic vapor, but in this case, the high temperature and high pressure conditions are particularly severe, making it easy for organic vapor to penetrate into the tube sheet, which can easily cause cracking in the tube sheet. In the method for producing a dehydrated organic compound using the gas separation system described above, either a hollow feed, in which the internal space of the hollow fiber membrane is the primary side (raw material gas supply side), or a shell feed, in which the external space of the hollow fiber membrane is the primary side, may be adopted.

[0074] In both shell feed and hollow feed configurations, the water-containing organic vapor mixture supplied from the mixed gas inlet to the primary space within the gas separation membrane module flows in contact with the surface of the hollow fiber membrane and is discharged outside the module through the non-permeable gas outlet. Meanwhile, the permeate gas that has permeated through the hollow fiber membrane is discharged outside the module through a permeate gas outlet located in the secondary space. Since the hollow fiber membrane has selective permeability, the permeate gas that has permeated through the membrane is rich in highly permeable components, while the non-permeable gas discharged from the non-permeable gas outlet has a reduced concentration of highly permeable components. The partial pressure of the highly permeable components is manipulated so that it is lower on the permeate side than on the supply side. For example, when using the separation membrane module shown in Figure 1, the water-containing organic vapor mixture is introduced from the mixed gas inlet 38 through the opening of the hollow fiber membrane into the internal space of the hollow fiber membrane 20. As the water-containing organic vapor mixture flows through the internal space of the hollow fiber membrane, the highly permeable components selectively permeate the membrane, and the permeated gas moves into the space between the tube sheets 50b and 50a where the hollow fiber bundle is housed. The non-permeable gas that does not permeate is discharged from the non-permeable gas outlet 41 through the space facing the other opening of the hollow fiber membrane. For example, water is enriched in the highly permeable components, and dehydrated organic compounds are obtained as non-permeable components.

[0075] In the above manufacturing method, permeation may be promoted by circulating a carrier gas over the secondary surface of the membrane. In this case, it is preferable that the carrier gas flows countercurrently with respect to the water-containing organic vapor mixture across the hollow fiber membrane. The carrier gas is not particularly limited as long as it does not contain highly permeable components, or at least the concentration of the highly permeable components is lower than that of the non-permeable gas. For example, nitrogen or air can be used. Alternatively, it is also preferable to circulate a portion of the non-permeable gas, from which the highly permeable components have been separated, to the carrier gas supply port and use it as the carrier gas.

[0076] In the example shown in Figure 1, a carrier gas guide film 37 is covered on the outer circumference of the hollow fiber bundle 30, from the point where the carrier gas is introduced until it is discharged. A core tube 70 is provided that penetrates the tube sheet 50b and is positioned along the hollow fiber bundle 30 approximately in the center of the bundle. A communication hole 15 is formed in the core tube, located near the tube sheet 50b on the carrier gas introduction side, connecting the internal space of the core tube with the hollow fiber bundle. When a carrier gas is used, the carrier gas is introduced from the carrier gas inlet 39 of the core tube 70, and then introduced from the communication hole 15 of the core tube 70 into the space between the tube sheets 50b and 50a where the hollow fibers are installed. The gas flows in contact with the outside of the hollow fiber membrane 20 and is discharged from the permeate gas outlet 42 along with the permeate gas from the hollow fiber membrane. Therefore, the flow of the mixed gas and carrier gas inside the module is countercurrent across the separation membrane.

[0077] In a method for producing a dehydrated organic compound using the gas separation method of the present invention, a mixed gas of water vapor and organic vapor can be suitably used as the mixed gas to be separated. The organic compounds mentioned above are preferably those with a boiling point of 0°C to 200°C at atmospheric pressure. The reason why the boiling point of the organic compounds is 0°C to 200°C is that it is practical when considering the operating temperature range of the hollow fiber membrane, the equipment for superheating the organic vapor mixture into vapor, the equipment for coagulating and recovering the purified and separated components, and the ease of handling. Organic compounds having a boiling point of 0°C or higher and 200°C or lower at atmospheric pressure include aliphatic alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, s-butanol, t-butanol, and ethylene glycol; alicyclic alcohols such as cyclohexanol; aromatic alcohols such as benzyl alcohol; organic carboxylic acids such as formic acid, acetic acid, propionic acid, and butyric acid; organic acid esters such as butyl acetate and ethyl acetate; ketones such as acetone and methyl ethyl ketone; cyclic ethers such as tetrahydrofuran and dioxane; organic amines such as butylamine and aniline; and mixtures of the above compounds.

[0078] In the method for producing dehydrated organic compounds using the separation system of the present invention, the water-containing organic compound is heated and evaporated by an evaporator (distillation) apparatus or the like, and supplied to the separation membrane module as a water-containing organic vapor mixture under atmospheric pressure to a pressurized state of approximately 0.1 to 10 atmospheres (gauge pressure). The water-containing organic vapor mixture supplied to the separation membrane module is preferably at a temperature of 80°C or higher, more preferably 100°C or higher, and even more preferably 120°C or higher. [Examples]

[0079] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. The compounds used in the following example are as follows: (1) Epoxy compound (a1) :jER630, manufactured by Mitsubishi Chemical Corporation, triglycidylaminophenol, epoxy equivalent: 98 (2) Epoxy compound (a2) :jER828, manufactured by Mitsubishi Chemical Corporation, liquid bisphenol A type epoxy compound, epoxy equivalent: 189 (3) Epoxy compound (a3) :jER604, manufactured by Mitsubishi Chemical Corporation, tetraglycidyldiaminodiphenylmethane, epoxy equivalent: 119 (4) Hardener (b1) :WANAMINE MDA-100, manufactured by Wanhua Chemical Group Co., Ltd., 4,4'-diaminodiphenylmethane, active hydrogen equivalent: 50 (5) Curing agent (b2): 3,4'-diaminodiphenyl ether, active hydrogen equivalent: 50

[0080] (Method for preparing cured resin compositions) (Examples 1-8, Comparative Examples 1-3) The epoxy compositions and curing agents listed in Table 1 (in parts by mass) were mixed to prepare the resin composition before curing. A cured product was prepared from the resin composition using the following method. (Method for preparing hardened material) A film formed by casting a resin composition was heated at 60°C for 24 hours to allow it to be primarily cured. Then, the temperature was increased to 90°C at a rate of 0.25°C / min and heated at 90°C for 2 hours. Next, the temperature was increased to 120°C at a rate of 0.25°C / min and heated at 120°C for 2 hours. Furthermore, the temperature was increased to 150°C at a rate of 0.25°C / min and heated at 150°C for 2 hours. Finally, the temperature was increased to 180°C at a rate of 0.25°C / min and heated at 180°C for 4 hours to allow it to cure, thereby creating a film made of cured resin composition with a thickness of approximately 0.20 mm. When mixing the epoxy compound and the curing agent, a solvent was used as needed.

[0081] [Table 1]

[0082] The cured films of the resin compositions obtained above were subjected to the following methods to measure their breaking strength in the standard state, after heating at 130°C in the presence of ethanol, and after heating at 150°C, as well as their elution rate during ethanol swelling. Cracking tests were also conducted on Examples 1 and 2 and Comparative Example 1. The results are shown in Table 2.

[0083] (Method for measuring fracture strength) A film made from the cured resin composition was cut into strips approximately 6 mm wide and 40 mm long to prepare test specimens. The breaking strength of each test specimen was measured using a tensile testing machine (Tensilon universal tester RTF-1350 (manufactured by A&D Co., Ltd.)) at a tensile speed of 2 mm / min and a chuck distance of 20 mm. The breaking strength under standard conditions was measured under controlled humidity conditions of 23°C and 50% RH. The measurement was performed after the test specimens were held under controlled humidity conditions for 10 hours or more. The average value of the measured values ​​for each of the 10 test specimens is shown in Table 2. This was defined as the breaking strength B0 under standard atmospheric conditions.

[0084] The aforementioned test specimen was placed in a sealed container (made of PTFE) with an internal volume of 50 ml, 20 ml of ethanol was added, and the specimen was immersed at 130°C for 120 hours. The fracture strength ratio measured immediately afterward was defined as the fracture strength B1 after heating in the presence of ethanol.

[0085] The test specimen was left standing in a sealed container at 150°C under 50% RH conditions for 10 minutes. After being removed from the container, the fracture strength ratio measured immediately was defined as the fracture strength B2 after heating at 150°C.

[0086] (Method for measuring elution rate) A film (0.2 mm thick) made from the cured resin composition was cut into strips approximately 6 mm wide and 40 mm long to form a sample, and its weight was measured to determine the weight before immersion. The sample was immersed in ethanol at 130°C for 120 hours in a sealed container, and then dried in a vacuum at 120°C for 72 hours. The weight of the dried sample was measured to determine the weight after immersion. The elution rate was calculated by dividing the difference between the weight before and after immersion by the weight of the sample before immersion and multiplying the result by 100.

[0087] <Cracking test> A hollow membrane with a diameter of 0.5 mm (the surface area of ​​one membrane is approximately 7.85 × 10⁻⁶). -5 m 2 A bundle of 1230 strands of the material (reference numeral 30 in Figure 3) was assembled, and a tube sheet 50, which is a cured product of the resin composition of the example and comparative example, was formed at one end of the bundle to have a diameter of 28.8 mm. The resulting hollow fiber elements were placed in an inner container 2 (inner diameter 44 mm) made of polytetrafluoroethylene (PTFE), and then 40 mL of ethanol was added to the inner container 2. The inner container 2 was placed in a stainless steel pressure vessel 1, and the pressure vessel 1 was left in a 130°C environment for 72 hours. Next, the hollow fiber elements that had been exposed to ethanol were dried at 130°C for 72 hours under atmospheric pressure. After drying, the tube sheets 50 were visually inspected and evaluated for cracks or no cracks according to the following criteria. Cracks present: Cracks were found on the side of the tube sheet when removed from ethanol, or after drying, cracks were observed between the hollow fibers and the tube sheet. No cracks: None of the above cracks were found.

[0088] [Table 2]

[0089] As shown in Table 2, in the examples of the present invention where the tensile strength retention rate R1 was 75% or higher, the elution rate after immersion in organic compounds under high temperature and high pressure was low, and no cracking of the tube sheet was observed even after drying after immersion in organic compounds under high temperature and high pressure. In contrast, in each comparative example where the tensile strength retention rate R1 was less than 75%, the elution rate after immersion in organic compounds under high temperature and high pressure was very high. Furthermore, in Comparative Example 1, cracking of the tube sheet was observed after drying after immersion in organic compounds under high temperature and high pressure. From these results, it can be concluded that by using the resin composition of the present invention as a hollow fiber element tube sheet, a tube sheet with excellent durability under high temperature, especially in the presence of organic vapor under high temperature and high pressure, and a separation membrane module with improved airtightness can be obtained. [Explanation of Symbols]

[0090] 38 Mixed gas inlet 39 Carrier gas inlet 42 Permeable gas outlet 41 Impermeable gas outlet 40 Pressure vessel 30 Hollow fiber bundle 20 Hollow fiber membrane 50(50a, 50b) tube sheet

Claims

1. A resin composition for hollow fiber element tube sheets comprising an epoxy composition and a curing agent, wherein the following fracture strength retention rate R was measured in the state of a 0.2 mm thick film-like cured product. １ A resin composition for hollow fiber element tube sheets, comprising 75% or more. R - Breaking strength retention rate １ (%) = B １ / B ０ ×100 B １ Breaking strength (MPa) at 23°C after immersion in ethanol at 130°C for 120 hours. B ０ Breaking strength (MPa) at 23°C before immersion in ethanol.

2. The resin composition for hollow fiber element tube sheets according to claim 1, wherein the alcohol elution rate measured in a 0.2 mm thick film-like cured material state after immersion in ethanol at 130°C for 120 hours is 2% or less.

3. Breaking strength B at 23°C, measured in the form of a 0.2 mm thick cured film. ０ The resin composition for hollow fiber element tube sheets according to claim 1 or 2, wherein the pressure is 30 MPa or more.

4. The epoxy composition comprises 20 to 90% by mass of an epoxy compound (a1) having a ring structure with an epoxy equivalent of 110 or less, and 10 to 60% by mass of an epoxy compound (a2) having a ring structure with an epoxy equivalent of 150 or more and 500 or less, as a resin composition for hollow fiber element tube sheets according to claim 1 or 2.

5. Epoxy compound (a1) is an epoxy compound having three or more epoxy groups on a single ring structure, and epoxy compound (a2) is a bisphenol A type epoxy compound. The resin composition for hollow fiber element tube sheets according to claim 4.

6. The resin composition for hollow fiber element tube sheets according to claim 1 or 2, wherein the curing agent is an amine compound having the structure of the following formula (1). 【Chemistry 1】 (In the formula, A １ This is a divalent group represented by any of the following formulas (2-1), (2-2), (2-3), (2-4), and (2-5). 【Chemistry 2】 (wherein, A ２ , A ３ and A ４ are each independently a divalent organic group having 1 to 18 carbon atoms.)

7. A １ The resin composition for hollow fiber element tube sheets according to claim 6, wherein is a divalent group represented by any one of the above formulas (2-1), (2-2), and (2-3).

8. A hollow fiber element in which at least one end of a bundle of fibers made up of a plurality of hollow fiber membranes is fixed and bound by a tube sheet formed from a cured product of the resin composition for hollow fiber element tube sheets described in claim 1 or 2.

9. A separation membrane module in which the hollow fiber element described in claim 8 is housed in a pressure vessel.

10. A gas separation system having the separation membrane module described in claim 9.

11. A method for producing a dehydrated organic compound using the gas separation system described in claim 10.

12. A hollow fiber element for a separation membrane module configuration, wherein at least one end of a plurality of hollow fiber membranes is fixed and bonded by a tubular sheet formed from a cured epoxy composition, The cured material is a hollow fiber element, measured in a 0.2 mm thick film form, with a fracture strength retention rate of 75% or more. Breaking strength retention rate (%) = B １ / B ０ ×100 B １ Breaking strength (MPa) at 23°C after immersion in ethanol at 130°C for 120 hours. B ０ Breaking strength (MPa) at 23°C before immersion in ethanol.

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