JP2019093309A - Gas separation membrane, gas separation module, gas separation device, and gas separation method - Google Patents

Abstract

To provide: a gas separation membrane having a gas separation layer that is excellent in both gas permeability and gas separation selectivity, exhibits excellent gas permeability and gas separation selectivity even under high pressure conditions, and is also less susceptible to influence of impurities such as toluene present in natural gas; and a gas separation module, a gas separation device and a gas separation method that use the gas separation membrane.SOLUTION: A gas separation membrane 10 contains a crosslinked polyimide compound, and has a crosslinked structure mediated by at least one linking group selected from among formulas (A-1) to (A-12), where Rto Reach independently represent a hydroxyl group, a halogen atom, an alkoxy group, or an aryloxy group.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a gas separation membrane, a gas separation module, a gas separation apparatus, and a gas separation method.

  Materials made of polymer compounds have gas permeability that is unique to each material. Based on its properties, a desired gas component can be selectively permeated and separated by a membrane composed of a specific polymer compound. As an industrial application of this gas separation membrane, it is considered to separate and recover it from a large-scale carbon dioxide source at a thermal power plant, cement plant, steel plant blast furnace, etc. in relation to the problem of global warming. It is done. And this membrane separation technology is focused as a solution to environmental problems that can be achieved with relatively small energy. On the other hand, natural gas and biogas (gases generated by biological excrement, organic fertilizers, biodegradable substances, sewage, garbage, fermentation of energy crops etc., anaerobic digestion) are mainly mixed gas containing methane and carbon dioxide As a means for removing such impurities such as carbon dioxide, a membrane separation method has been studied (Patent Document 1).

In the purification of natural gas using a membrane separation method, excellent gas permeability and gas separation selectivity are required in order to separate the gas more efficiently. In order to realize this, various membrane materials have been studied, and as a part thereof, examinations have been made on gas separation membranes using a polyimide compound.
In an actual plant, the membrane is plasticized due to high pressure conditions and the effects of impurities (for example, benzene, toluene, xylene) present in natural gas, and this causes a problem of reduced gas separation selectivity. Therefore, the gas separation membrane not only improves gas permeability and gas separation selectivity, but also plasticization resistance that can maintain high gas permeability and gas separation selectivity even under high pressure conditions and the presence of the above-mentioned impurities. Desired. As a means for solving the problem, research and development has been conducted to crosslink polyimide.
For example, Patent Document 2 shows that a crosslinked polyimide membrane obtained by self-condensing a polyimide having a hydroxyl group and a carboxy group by high temperature treatment has excellent performance in both gas permeability and gas separation selectivity even under high pressure. It is stated that indicated.
Further, in Non-Patent Document 1, a gas separation membrane having an asymmetric hollow fiber structure in which a polyimide compound crosslinked with a specific ester group exhibited excellent performance and high resistance even in the presence of impurities such as toluene It is described.

In order to obtain a practical gas separation membrane, it is necessary to thin the gas separation layer to ensure sufficient gas permeability, and also to realize a high degree of gas separation selectivity. As a method of thinning the gas separation layer, there is a method of using a polymer compound such as a polyimide compound as an asymmetric membrane by a phase separation method, and making a portion contributing to separation a thin layer called a dense layer or a skin layer. In this asymmetric membrane, the portion other than the dense layer is made to function as a support layer responsible for the mechanical strength of the membrane.
In addition to the above asymmetric membrane, the gas separation layer responsible for the gas separation function and the support layer responsible for the mechanical strength are separate materials, and the gas separation layer having the gas separation ability is a thin layer on the gas permeable support layer. The form of the composite film to be formed is also known.

Unexamined-Japanese-Patent No. 2007-297605 U.S. Published Patent 2015/0093510

Journal of Membrane Science, 2011, Vol. 369, p. 490-498

In general, gas permeability and gas separation selectivity are under the so-called trade-off rule of one another. Therefore, although either the gas permeability or gas separation selectivity of the gas separation layer can be improved by adjusting the copolymerization component of the polyimide compound used for the gas separation layer, both characteristics can be compatible at a high level. It is considered difficult to do.
In addition to methane gas, various higher order hydrocarbon gases such as propane and butane exist in natural gas. Therefore, not only the separation performance of methane but also the performance that can efficiently separate hydrocarbon gases in general is required for gas separation membranes.

  The present invention is excellent in both gas permeability and gas separation selectivity, exhibits excellent gas permeability and gas separation selectivity even under high pressure conditions, and is also affected by impurities such as toluene present in natural gas. It is an object of the present invention to provide a gas separation membrane having a gas separation layer which is hard to be received. Another object of the present invention is to provide a gas separation module, a gas separation apparatus, and a gas separation method using the gas separation membrane.

  As a result of intensive investigations in view of the above problems, the present inventors introduce a hydrophilic polar group to a polyimide compound constituting a gas separation layer, and further, a compact, hydrophilic cross-linked group having a relatively short chain length. It has been found that by introducing a gas separation membrane which is excellent in both gas permeability and gas separation selectivity even under high pressure and shows excellent resistance to impurities such as toluene. The present invention has been completed based on these findings.

上記式中、Ｒ^ａ、Ｒ^ｂおよびＲ^ｃはそれぞれ独立に、水酸基、ハロゲン原子、アルコキシ基またはアリールオキシ基を示す。
［２］
上記連結基が、下記（Ｂ−１）〜（Ｂ−６）からなる群から選ばれる少なくとも１種である、［１］に記載のガス分離膜。

［３］
上記架橋ポリイミド化合物が、式（Ｉ−ａ）で表される繰り返し単位の少なくとも一種を含む、［１］又は［２］に記載のガス分離膜。

式（Ｉ−ａ）中、Ｒは下記式（Ｉ−１）〜（Ｉ−２８）のいずれかで表される４価の基を示す。Ｒ^３は置換基を示す。ｍ１は０〜３の整数である。Ｘ^ａは−Ｂ（ＯＨ）−Ｏ−、−Ｐ（＝Ｏ）（ＯＨ）−Ｏ−又は−Ｐ（ＯＨ）−Ｏ−を示す。
ここでＸ^１〜Ｘ^３は単結合又は２価の連結基を、Ｌは−ＣＨ＝ＣＨ−又は−ＣＨ_２−を、Ｒ^１及びＲ^２は水素原子又は置換基を示し、＊は式（Ｉ−ａ）中のカルボニル基との結合部位を示す。

［４］
上記式（Ｉ−ａ）において、Ｒが下記式（Ｉ−ａ１）で表される、［３］に記載のガス分離膜。

［５］
上記架橋ポリイミド化合物が、下記式（Ｉ−ａ２）で表される繰り返し単位を含む、［１］〜［４］のいずれかにガス分離膜。

式（Ｉ−ａ２）中、Ｒ^Ｉ _４は水素原子、アルキル基又はハロゲン原子を示す。Ｘ^ａは−Ｂ（ＯＨ）−Ｏ−、−Ｐ（＝Ｏ）（ＯＨ）−Ｏ−又は−Ｐ（ＯＨ）−Ｏ−から選択される基を示す。
［６］
上記ガス分離膜が、上記ガス分離層をガス透過性の支持層上側に有するガス分離複合膜である、［１］〜［５］のいずれかに記載のガス分離膜。
［７］
上記支持層が、ガス分離層側の多孔質層と、その逆側の不織布層とからなる、［６］に記載のガス分離膜。
［８］
分離処理されるガスが二酸化炭素とメタンの混合ガスである場合において、４０℃、５ＭＰａにおける二酸化炭素の透過速度が２０ＧＰＵ超であり、二酸化炭素とメタンとの透過速度比（Ｒ_ＣＯ２／Ｒ_ＣＨ４）が１５以上である、［１］〜［７］のいずれかに記載のガス分離膜。
［９］
分離処理されるガスが二酸化炭素とブタンの混合ガスである場合において、４０℃、５ＭＰａにおける二酸化炭素の透過速度が２０ＧＰＵ超であり、二酸化炭素とブタンとの透過速度比（Ｒ_ＣＯ２／Ｒ_{Ｃ４Ｈ１０}）が４０以上である、［１］〜［７］のいずれかに記載のガス分離膜。
［１０］
二酸化炭素及び炭化水素ガスを含むガスから二酸化炭素を選択的に透過させるために用いられる、［１］〜［９］のいずれかに記載のガス分離膜。
［１１］
［１］〜［１０］のいずれかに記載のガス分離膜を具備するガス分離モジュール。
［１２］
［１１］に記載のガス分離モジュールを備えたガス分離装置。
［１３］
［１］〜［９］のいずれかに記載のガス分離膜を用いたガス分離方法。 The above task has been achieved by the following means.
[1]
A gas separation membrane comprising a crosslinked polyimide compound, wherein the crosslinked polyimide compound has a crosslinked structure via at least one connecting group selected from the group consisting of the following (A-1) to (A-12): Has a gas separation membrane.

In the above formulae, R ^a , R ^b and R ^c each independently represent a hydroxyl group, a halogen atom, an alkoxy group or an aryloxy group.
[2]
The gas separation membrane according to [1], wherein the linking group is at least one selected from the group consisting of (B-1) to (B-6) below.

[3]
The gas separation membrane as described in [1] or [2] in which the said crosslinked polyimide compound contains at least 1 type of a repeating unit represented by Formula (Ia).

In formula (I-a), R represents a tetravalent group represented by any of the following formulas (I-1) to (I-28). R ³ represents a substituent. m1 is an integer of 0 to 3. X ^a represents -B (OH) -O-, -P (= O) (OH) -O- or -P (OH) -O-.
Here, X ^{1 to} X ^{3 each} represent a single bond or a divalent linking group, L represents -CH = CH- or -CH _2- , R ¹ and R ^{2 each} represent a hydrogen atom or a substituent, and * represents a formula ( The binding site to the carbonyl group in I-a) is shown.

[4]
The gas separation membrane as described in [3] in which R is represented by a following formula (I-a1) in said formula (I-a).

[5]
The gas separation membrane is any of [1]-[4] in which the said crosslinked polyimide compound contains the repeating unit represented by a following formula (I-a2).

In formula (I-a2), R ^I ₄ represents a hydrogen atom, an alkyl group or a halogen atom. X ^a represents a group selected from -B (OH) -O-, -P (= O) (OH) -O- or -P (OH) -O-.
[6]
The gas separation membrane according to any one of [1] to [5], wherein the gas separation membrane is a gas separation composite membrane having the gas separation layer on the upper side of a gas permeable support layer.
[7]
The gas separation membrane according to [6], wherein the support layer comprises a porous layer on the gas separation layer side and a non-woven fabric layer on the opposite side thereof.
[8]
When the gas to be separated and processed is a mixed gas of carbon dioxide and methane, the permeation rate of carbon dioxide at 40 ° C. and 5 MPa is more than 20 GPU, and the permeation rate ratio of carbon dioxide to methane (R _CO2 / R _CH4 ) Is 15 or more, The gas separation membrane in any one of [1]-[7].
[9]
When the gas to be separated and processed is a mixed gas of carbon dioxide and butane, the permeation rate of carbon dioxide at 40 ° C. and 5 MPa is more than 20 GPU, and the permeation rate ratio of carbon dioxide to butane (R _CO2 / R _{C4 H10} ) Is 40 or more, The gas separation membrane in any one of [1]-[7].
[10]
The gas separation membrane according to any one of [1] to [9], which is used to selectively permeate carbon dioxide from a gas containing carbon dioxide and a hydrocarbon gas.
[11]
The gas separation module which comprises the gas separation membrane in any one of [1]-[10].
[12]
[11] A gas separation apparatus comprising the gas separation module according to [11].
[13]
The gas separation method using the gas separation membrane in any one of [1]-[9].

The numerical range represented by "-" in this specification is a meaning which includes the numerical value described before and after that as a lower limit and an upper limit.
In the present specification, when there are a plurality of substituents, linking groups and the like (hereinafter referred to as substituents and the like) represented by specific symbols, or when a plurality of substituents and the like are defined simultaneously or alternatively, The substituents and the like mean that they may be the same or different. The same applies to the definition of the number of substituents and the like. Moreover, when there exists repetition of several partial structure represented by the same display in Formula, each partial structure thru | or repeating unit may be same or different. Also, even if not particularly mentioned, it means that when a plurality of substituents and the like are adjacent, they may be linked to each other or condensed to form a ring.

In the present specification, the term "compound" or "group" is used in the meaning including the compound or group itself as well as the salts thereof and the ions thereof. Moreover, it is a meaning including the derivative which changed a part of structure in the range which show | plays the target effect.
In the present specification, with respect to a substituent which does not specify substitution or non-substitution (the same applies to a linking group), it is a meaning that the group may have any substituent within a range that produces a desired effect. . This is also the same as for compounds in which no substitution or substitution is specified.
When a substituent is referred to in the present specification, unless otherwise specified, the following substituent group Z is the preferable range.

  The gas separation membrane, the gas separation module, and the gas separation device of the present invention are excellent in gas permeability even under high pressure conditions, and also excellent in gas separation performance. In addition, even when used for the separation of a gas containing an impurity such as toluene, the decrease in gas separation performance hardly occurs.

  According to the gas separation method of the present invention, gas can be separated with excellent gas permeability and excellent gas separation selectivity even under high pressure conditions. In addition, even if impurities are present in the gas to be separated, excellent gas separation performance is maintained.

1 is a cross-sectional view schematically showing an embodiment of a gas separation composite membrane of the present invention. It is sectional drawing which shows typically another embodiment of the gas-separation composite film of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The gas separation membrane of the present invention contains a specific crosslinked polyimide compound in the gas separation layer.

[Crosslinked polyimide compound]
The crosslinked polyimide compound used in the present invention has a crosslinked structure via at least one type of linking group selected from the group consisting of the following (A-1) to (A-12).

In the above formulae, R ^a , R ^b and R ^c each independently represent a hydroxyl group, a halogen atom, an alkoxy group or an aryloxy group.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom, a fluorine atom, a chlorine atom or a bromine atom is more preferable, and a fluorine atom or a chlorine atom is more preferable.

The alkoxy group is preferably an alkoxy group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms, and examples thereof include methoxy, ethoxy, butoxy and 2-ethylhexyloxy Be
The aryloxy group is preferably an aryloxy group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyloxy, 1-naphthyloxy and 2-naphthyloxy Etc.

  The specific linking group is preferably at least one selected from the group consisting of (B-1) to (B-6) below.

  Among these linking group group (B), preferred are groups directly bonded from carbon atoms of the main chain of the polyimide compound. Specifically, (B-1), (B-3) and (B-5) may be mentioned.

  It is preferable that the said crosslinked polyimide compound contains at least 1 type of the repeating unit represented by Formula (I-a).

In formula (I-a), R represents a tetravalent group represented by any of the following formulas (I-1) to (I-28). R ³ represents a substituent. m1 is an integer of 0 to 3. X ^a represents -B (OH) -O-, -P (= O) (OH) -O- or -P (OH) -O-.

Examples of the substituent that can be taken as R ³ include groups selected from Substituent Group Z described later.

  m1 is an integer of 0 to 3, preferably 1 to 3.

Here, X ^{1 to} X ^{3 each} represent a single bond or a divalent linking group, L represents -CH = CH- or -CH _2- , R ¹ and R ^{2 each} represent a hydrogen atom or a substituent, and * represents a formula ( The binding site to the carbonyl group in I-a) is shown. R is preferably a group represented by formula (I-1), (I-2) or (I-4), and is a group represented by (I-1) or (I-4) Is more preferable, and a group represented by (I-1) is particularly preferable.

In the formulas (I-1), (I-9) and (I-18), X ^{1 to} X ^{3 each} represent a single bond or a divalent linking group. As the divalent linking group, —C (R ^x ) ₂ — (R ^x represents a hydrogen atom or a substituent. When R ^x is a substituent, they may be linked to each other to form a ring), -O-, -SO _2- , -C (= O)-, -S-, -NR ^Y- (where R ^Y is a hydrogen atom, an alkyl group (preferably a methyl group or an ethyl group) or an aryl group (preferably a phenyl group) _{group)), - C 6 H 4} - ( phenylene group), or a combination thereof, more preferably a single bond or -C ^(R _{x) 2} - are more preferable. When R ^x represents a substituent, specific examples thereof include a group selected from Substituent Group Z, and in particular, an alkyl group (a preferred range is the same as the alkyl group shown in Substituent Group Z) Some are preferable, an alkyl group having a halogen atom as a substituent is more preferable, and trifluoromethyl is particularly preferable. In Formula (I-18), X ³ is linked to any one of the two carbon atoms described on the left side or one of the two carbon atoms described on the right side. Means to

In the above formulas (I-4), (I-15), (I-17), (I-20), (I-21) and (I-23), L is -CH = CH- or -CH ₂ Indicates-.

R < ¹ > and R < ² > show a hydrogen atom or a substituent in said Formula (I-7). Examples of such a substituent include groups selected from Substituent Group Z described later. R ¹ and R ² may be bonded to each other to form a ring.
R ¹ and R ² are preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom, a methyl group or an ethyl group, and still more preferably a hydrogen atom.

  The carbon atom shown in formulas (I-1) to (I-28) may further have a substituent. Specific examples of the substituent include groups selected from the following Substituent Group Z, and among them, an alkyl group or an aryl group is preferable.

  In the above formula (I-a), R is preferably represented by the following formula (I-a1).

  It is preferable that the said crosslinked polyimide compound contains the repeating unit represented by following formula (I-a2).

In formula (I-a2), R ^I ₄ represents a hydrogen atom, an alkyl group or a halogen atom. X ^a is as defined in formula (I-a). Here, as a halogen atom, it is synonymous with having demonstrated by the said coupling group group A, The preferable range is also the same. The alkyl group may be linear or branched and may have a cyclic structure. The alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, still more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and most preferably 1 to 4 carbon atoms. Preferred specific examples of this alkyl group include, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, s-butyl, isobutyl, cyclobutyl, n-hexyl and cyclohexyl, and methyl is particularly preferable. preferable.

  When the repeating unit constituting the crosslinked polyimide compound used in the present invention "has at least one selected from the linking group group A", this highly polar crosslinked linking group is hydrophobic with respect to impurities such as toluene It is difficult to swell, and when such a crosslinked polyimide compound is used in a gas separation layer, it is possible to achieve both excellent gas separation selectivity and excellent gas permeability at a high level, and also be excellent in plastic resistance. It becomes.

(Crosslinked structure)
In the present invention, the crosslinked structure of the crosslinked polyimide resin has at least one linking group selected from the above linking group group. The preferable range is also the same as that described in the section of the connecting group group.
The crosslinking density in the crosslinked polyimide compound means, for example, the density of the polyimide compound reacted with the crosslinking agent. That is, it means the density of the structural formula after the reaction represented by the following [Chemical formula 13 to Chemical formula 17].

[Crosslinked polyimide resin]
(Crosslinking site ratio [η])
In the present invention, the ratio [η] (the number of crosslinking sites / the number of imide groups) of the imide group of the above-mentioned polyimide compound and the crosslinking site in the above-mentioned crosslinked polyimide resin is 0.0001 to 0.45, 0. It is preferably 01 to 0.3, more preferably 0.01 to 0.2, and still more preferably 0.01 to 0.1. Furthermore, when setting the low crosslinking site ratio, 0.05 or less is preferable, 0.04 or less is more preferable, and 0.02 or less is particularly preferable.

In the present specification, “crosslinking site ratio [η]” is based on the number of crosslinkable functional groups that have been crosslinked, and may be introduced into the polyimide compound, and the number of crosslinkable functional groups that have not been crosslinked is It is the excluded calculated value (ratio). By setting this value to the above lower limit value or higher, the film is plasticized under the condition of high CO ₂ concentration or by the influence of aromatic compounds such as benzene, toluene and xylene contained in natural gas or hydrocarbon impurities such as hexane and heptane. It is possible to minimize the decrease in separation selectivity associated with On the other hand, by setting the upper limit value or less, it is possible to minimize the decrease in gas permeability accompanied by the improvement of the crosslinking density, and further to improve the mechanical strength such as cracking and brittleness at the time of bending.
In order to make this crosslinking site ratio into a desired range, the proportion of functional crosslinking groups (eg, the density of crosslinking functional groups [γ] described later) is appropriately adjusted during synthesis of the polyimide compound, or the crosslinking reaction conditions are changed. It is possible to carry out by adjusting the crosslinking conversion rate (for example, the ratio of the number of crosslinked functional groups to the total number of crosslinking functional groups (crosslinking conversion rate) [α]). ] = [Γ] x [α] / 200. Here, with regard to the denominator, since the polyimide has two imide groups per constituent unit component, it is 200 × 100. Specifically, the crosslinking site ratio is increased by increasing the compositional ratio of the monomer having a crosslinking site within a predetermined range, enhancing the reactivity, polyfunctionalizing or using a material having another crosslinking substituent. [Η] can be increased.

(Crosslinkable functional group density [γ])
R ^P -O-B (-O-R ^P ) -O-R in the structural formula after reaction represented by the following [Chemical Formula 13 to Chemical Formula 17] with respect to the repeating unit represented by Formula (I-a) The ratio of numbers such as ^P is called crosslinkable functional group density [γ]. The preferable range of this γ {(number of such as R ^P -O-B (-O-R ^P ) -O-R ^P ) / (number of repeating units represented by the formula (I-a))} is 0 And more preferably 0.003 to 0.56.

  The crosslinkable functional group density can be adjusted by the preparation amount of the substrate (monomer) when synthesizing the polyimide compound.

(Crosslinking conversion rate [α])
The crosslinking conversion ratio [α] of the present invention is a Raman spectroscopy measurement of a film (for example, in the case of borate crosslinking, a peak of boron-oxygen bond (700 to 900 cm ⁻¹ )) and solid state NMR (various: 11B) spectra It can be calculated by the decrease before and after crosslinking. 20% or more and 100% or less is preferable, 50% or more and 94% or less is more preferable, and 30% or more and 89% or less is more preferable.

The crosslinking conversion ratio can be adjusted by the crosslinking conditions of the polyimide compound, and the kind or addition amount of the crosslinking agent, or the temperature in the crosslinking reaction, substrate concentration, heat quantity, light quantity of actinic radiation and / or irradiation time By adjusting, the crosslinking conversion can be adjusted. Specifically, for example, in order to increase the reaction rate in the crosslinking reaction, the total energy of heat or light energy is increased, or in the case of a material, the reactivity of the crosslinking agent is increased (for example, substitution with halogen having high elimination ability) Compounds of boron or phosphorus, etc. For example, in the case of a boron-based crosslinking agent, BCl ₃ is more reactive than B (OH) ₃ ) or by increasing the amount of the crosslinking agent. To raise the activity.

  Although the example of a crosslinking reaction is shown by reaction scheme below, this invention is not limited and interpreted to this. In addition, polymer shows a "polyimide residue" in a following formula.

反応式：３Ｒ^Ｐ−ＯＨ ＋ Ｂ（Ｒ^３）_３（この一番目の反応は、架橋の１つ前の段階と理解される。以下同様。）
⇒ Ｒ^Ｐ−Ｏ−Ｂ（Ｒ^３）_２ ＋ Ｒ^３Ｈ
⇒ Ｒ^Ｐ−Ｏ−Ｂ（Ｒ^３）−Ｏ−Ｒ^Ｐ ＋ Ｒ^３Ｈ
⇒ Ｒ^Ｐ−Ｏ−Ｂ（−Ｏ−Ｒ^Ｐ）−Ｏ−Ｒ^Ｐ ＋ Ｒ^３Ｈ
ここで、Ｒ^Ｐは、ポリイミド化合物（ポリマー）の残基を表す。Ｒ^３は、ハロゲン原子、水酸基、アルコキシ基又はアリールオキシ基を示す。 (1) Boric acid (borate) crosslinking

Reaction formula: 3R ^P -OH + B (R ³ ) ₃ (This first reaction is understood to be one step before crosslinking. The same applies hereinafter.)
^P R ^P- O-B (R ³ ) ₂ + R ³ H
^P R ^P -O-B (R ³ ) -O-R ^P + R ³ H
^P R ^P -O-B (-O-R ^P ) -O-R ^P + R ³ H
Here, R ^P represents a residue of a polyimide compound (polymer). R ³ represents a halogen atom, a hydroxyl group, an alkoxy group or an aryloxy group.

反応式：２Ｒ^Ｐ−Ｂ（ＯＨ）_２ ＋ Ｘ_１−Ｌ_１−Ｘ_２
⇒ Ｒ^Ｐ−Ｂ（ＯＨ）−Ｏ−Ｌ_１−Ｘ_２ ＋ ＨＸ_１
⇒ Ｒ^Ｐ−Ｂ（ＯＨ）−Ｏ−Ｌ_１−Ｏ−Ｂ（ＯＨ）−Ｒ^Ｐ ＋ ＨＸ_２
ここで、Ｒ^Ｐは、上記と同義である。Ｘ_１は、ハロゲン原子、水酸基、アルコキシ基又はアリールオキシ基を示す。Ｌ_１は、ホウ素原子、リン原子、アルキレン基又はアリーレン基を示す。Ｘ_２は、ハロゲン原子、水酸基、アルコキシ又はアリールオキシ基を示す。 (2) Boric acid (borate) crosslinking

Reaction formula: 2R ^P- B (OH) ₂ + X _1- L _1- X ₂
R R ^P- B (OH)-O L _1- X ₂ + HX ₁
R R ^P- B (OH)-O L _1- O B (OH)-R ^P + HX ₂
Here, R ^P is as defined above. X ₁ represents a halogen atom, a hydroxyl group, an alkoxy group or an aryloxy group. L ₁ represents a boron atom, a phosphorus atom, an alkylene group or an arylene group. X ₂ represents a halogen atom, a hydroxyl group, an alkoxy or an aryloxy group.

反応式：３Ｒ^Ｐ−ＯＨ ＋ Ｐ（Ｒ^３）_３
⇒ Ｒ^Ｐ−Ｏ−Ｐ−（Ｒ^３）_２ ＋ Ｒ^３Ｈ
⇒ Ｒ^Ｐ−Ｏ−Ｐ（Ｒ^３）−Ｏ−Ｒ^Ｐ ＋ Ｒ^３Ｈ
⇒ Ｒ^Ｐ−Ｏ−Ｐ（−Ｏ−Ｒ^Ｐ）−Ｏ−Ｒ^Ｐ ＋ Ｒ^３Ｈ
ここで、Ｒ^ＰとＲ^３は、それぞれ上記と同義である。 (3) (phosphite crosslink)

Reaction formula: 3R ^P -OH + P (R ³ ) ₃
^P R ^P -O-P- (R ³ ) ₂ + R ³ H
^P R ^P -O-P (R ³ ) -O-R ^P + R ³ H
^P R ^P -O-P (-O-R ^P ) -O-R ^P + R ³ H
Here, R ^P and R ³ are as defined above.

反応式：３Ｒ^Ｐ−ＯＨ ＋ Ｐ（＝Ｏ）（Ｒ^３）_３
⇒ Ｒ^Ｐ−Ｏ−Ｐ（＝Ｏ）−（Ｒ^３）_２ ＋ Ｒ^３Ｈ
⇒ Ｒ^Ｐ−Ｏ−Ｐ（＝Ｏ）（Ｒ^３）−Ｏ−Ｒ^Ｐ ＋ Ｒ^３Ｈ
⇒ Ｒ^Ｐ−Ｏ−Ｐ（＝Ｏ）（−Ｏ−Ｒ^Ｐ）−Ｏ−Ｒ^Ｐ ＋ Ｒ^３Ｈ
ここで、Ｒ^ＰとＲ^３は、それぞれ上記と同義である。 (4) (phosphonate crosslink)

Reaction formula: 3R ^P -OH + P (= O) (R ³ ) ₃
^P R ^P -O-P (= O)-(R ³ ) ₂ + R ³ H
^P R ^P -O-P (= O) (R ³ ) -O-R ^P + R ³ H
^{⇒ R P -O-P (=} O) (- O-R P) -O-R P + R 3 H
Here, R ^P and R ³ are as defined above.

反応式：２Ｒ^Ｐ−Ｐ（＝Ｏ）（ＯＨ）_２ ＋ Ｘ_１−Ｌ_１−Ｘ_２
⇒ Ｒ^Ｐ−Ｐ（＝Ｏ）（ＯＨ）−Ｏ−Ｌ_１−Ｘ_２ ＋ ＨＸ_１
⇒ Ｒ^Ｐ−Ｐ（＝Ｏ）（ＯＨ）−Ｏ−Ｌ_１−Ｏ−Ｐ（＝Ｏ）（ＯＨ）−Ｒ^Ｐ ＋ ＨＸ_２
ここで、Ｒ^Ｐ、Ｘ_１、Ｌ_１及びＸ_２は、それぞれ上記と同義である。 (5) (phosphonate crosslink)

Reaction formula: 2R ^P- P (= O) (OH) ₂ + X _1- L _1- X ₂
R R ^P- P (= O) (OH)-O L _1- X ₂ + H X ₁
R R ^P- P (= O) (OH)-O-L _1- O-P (= O) (OH)-R ^P + HX ₂
Here, R ^P , X ₁ , L ₁ and X ₂ are as defined above.

  The polyimide compound used in the present invention may have a repeating unit represented by the following formula (II-a) or (II-b) in addition to the repeating unit represented by the above formula (I-a) .

In said formula (II-a) and (II-b), R is synonymous with R in a formula (I-a), and its preferable form is also the same. R ^{4 to} R ^{6 each} represent a substituent. As a substituent, the group chosen from the substituent group Z mentioned later is mentioned.
R ⁴ is preferably an alkyl group, a carboxy group or a halogen atom. L1 indicating the number of R ⁴ is an integer from 0 to 4, when ^{R 4} is an alkyl group, l1 is preferably 1 to 4, more preferably 2 to 4, more preferably 3 or 4 When R ⁴ is a carboxy group, 11 is preferably 1 to 2, more preferably 1. When R ⁴ is an alkyl group, the carbon number of the alkyl group is preferably 1 to 10, more preferably 1 to 5, still more preferably 1 to 3, and particularly preferably methyl, Ethyl or trifluoromethyl.
In the formula (II-a), two linking sites to be incorporated into the polyimide compound of the diamine component (that is, a phenylene group capable of having R ⁴ ) are preferably located at the meta position or the para position.

It is preferred that R ⁵ and R ⁶ represent an alkyl group or a halogen atom, or a group which forms a ring with X ^{4 in combination} with each other. Also preferred is a form in which two R ⁵ are linked to form a ring, and a form in which two R ⁶ are linked to form a ring. There is no particular limitation on the structure in which R ⁵ and R ⁶ are connected, but it is preferable to form a ring by a single bond, -O- or -S- as a connecting group. M1 and n1 indicating the number of R ⁵ and R ⁶ are integers of 0 to 4, preferably 1 to 4, more preferably 2 to 4, and still more preferably 3 or 4. When R ⁵ and R ⁶ are alkyl groups, the number of carbon atoms of the alkyl group is preferably 1 to 10, more preferably 1 to 5, still more preferably 1 to 3, and particularly preferably Is methyl, ethyl or trifluoromethyl.
In the formula (II-b), two linking sites to be incorporated into the polyimide compound of two phenylene groups (that is, two phenylene groups capable of having R ⁵ and R ⁶ ) in the diamine component are X ⁴ links Preferably, they are located at the meta or para position relative to one another relative to the site.

X ⁴ represents a single bond or a divalent linking group. Examples of the divalent linking group X ⁴ can take the above formula (I-1), (I -9) and (I-18) in the same meaning as ^X 1 to X ^3, its preferred embodiments are also the same is there.
However, the repeating unit included in the repeating unit represented by Formula (I-a) is not included in the repeating unit represented by Formula (II-a).

  The polyimide compound used in the present invention is represented by the repeating unit represented by the above formula (I-a), the repeating unit represented by the above formula (II-a), and the above formula (II-b) in the structure. The ratio of the molar amount of the repeating unit represented by the formula (I-a) in the total molar amount of the repeating unit to be mixed is preferably 10 to 100 mol%, and is 50 to 100 mol% Is more preferably 70 to 100 mol%, still more preferably 80 to 100 mol%, and particularly preferably 90 to 100 mol%. In the total molar amount of the repeating unit represented by the above formula (I-a) and the repeating unit represented by the above formula (II-a) and the repeating unit represented by the above formula (II-b) When the proportion of the molar amount of the repeating unit represented by the formula (I-a) is 100 mol%, the polyimide compound is a repeating unit represented by the above formula (II-a) and the above formula (I It means that it does not have any of the repeating units represented by II-b).

  The polyimide compound used in the present invention is composed of the repeating unit represented by the above formula (I-a) or has a repeating unit other than the repeating unit represented by the above formula (I-a), It is preferable that remainder other than the repeating unit represented by said Formula (I-a) consists of a repeating unit represented by said Formula (II-a) or said Formula (II-b). Here, “composed of the repeating unit represented by the above formula (II-a) or the above formula (II-b)” means an embodiment comprising the repeating unit represented by the above formula (II-a), the above formula 3) an aspect comprising the repeating unit represented by (II-b), and an aspect comprising the repeating unit represented by the above formula (II-a) and the repeating unit represented by the above formula (II-b) Meaning including one aspect.

Substituent group Z:
An alkyl group (preferably an alkyl group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 10 carbon atoms, and examples thereof include methyl, ethyl, iso-propyl, tert-butyl and n-octyl And n-decyl, n-hexadecyl etc., cycloalkyl groups (preferably having 3 to 30 carbon atoms, more preferably 3 to 20 carbon atoms, and particularly preferably 3 to 10 carbon atoms. For example, cyclopropyl, cyclopentyl, cyclohexyl etc., alkenyl groups (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 10 carbon atoms; And vinyl, allyl, 2-butenyl, 3-pentenyl and the like), an alkynyl group (preferably having a carbon number of 2 to 2). The alkynyl group is preferably an alkynyl group having 0, more preferably 2 to 20 carbon atoms, particularly preferably 2 to 10 carbon atoms, and examples thereof include propargyl, 3-pentynyl and the like), aryl groups (preferably 6 to 30 carbon atoms) The aryl group is preferably an aryl group having 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and anthranyl), an amino group (amino group, alkylamino group, An amino group containing an arylamino group and a heterocyclic amino group, preferably an amino group having 0 to 30 carbon atoms, more preferably 0 to 20 carbon atoms, and particularly preferably 0 to 10 carbon atoms, such as amino, methylamino, dimethylamino , Diethylamino, dibenzylamino, diphenylamino, ditolylamino etc.), alkoxy group The alkoxy group is preferably an alkoxy group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms, and examples thereof include methoxy, ethoxy, butoxy and 2-ethylhexyloxy). An aryloxy group (preferably an aryloxy group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyloxy, 1-naphthyloxy, 2-naphthyloxy and the like And heterocyclic oxy groups (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms), such as pyridyloxy, pyrazyloxy, Pyrimidyloxy, quinolyloxy etc.),

  Acyl group (preferably an acyl group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, such as acetyl, benzoyl, formyl, pivaloyl and the like), and alkoxy A carbonyl group (preferably an alkoxycarbonyl group having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 12 carbon atoms, and examples thereof include methoxycarbonyl and ethoxycarbonyl), and aryloxy A carbonyl group (preferably an aryloxycarbonyl group having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, and particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonyl and the like), an acyloxy group ( The number of carbon atoms is preferably 2 to 30, more preferably 2 to 20, and particularly preferably Or an acyloxy group having 2 to 10 carbon atoms, and examples thereof include acetoxy, benzoyloxy and the like), an acylamino group (preferably having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 carbon atoms And 2 to 10 acylamino groups, such as acetylamino and benzoylamino).

  Alkoxycarbonylamino group (preferably an alkoxycarbonylamino group having 2 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, and particularly preferably 2 to 12 carbon atoms, such as methoxycarbonylamino, etc., aryl An oxycarbonylamino group (preferably an aryloxycarbonylamino group having 7 to 30 carbon atoms, more preferably 7 to 20 carbon atoms, and particularly preferably 7 to 12 carbon atoms, and examples thereof include phenyloxycarbonylamino and the like). , Sulfonylamino group (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfonylamino, benzenesulfonylamino and the like) and sulfamoyl group. (Preferably having a carbon number of 0 to 30, more preferably 0 to 20 carbon atoms, particularly preferably a sulfamoyl group having 0 to 12 carbon atoms, for example sulfamoyl, methylsulfamoyl, dimethylsulfamoyl, and the like phenylsulfamoyl.),

  An alkylthio group (preferably an alkylthio group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples include methylthio and ethylthio), and an arylthio group (preferably The arylthio group is preferably an arylthio group having 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, and particularly preferably 6 to 12 carbon atoms, and examples thereof include phenylthio and the like, heterocyclic thio groups (preferably 1 to 30 carbon atoms). More preferably a heterocyclic thio group having 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include pyridylthio, 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio and the like. Can be mentioned),

  A sulfonyl group (preferably a sulfonyl group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and includes, for example, mesyl, tosyl, etc.), a sulfinyl group (preferably It is a sulfinyl group having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and particularly preferably 1 to 12 carbon atoms, and examples thereof include methanesulfinyl and benzenesulfinyl, etc., and ureido group (preferably 1 carbon atom). A ureido group having a carbon number of 1 to 30, more preferably 1 to 20, particularly preferably 1 to 12, and examples thereof include ureide, methyl ureido and phenyl ureido), phosphoric acid amide group (preferably carbon number) A phosphoric acid amide group having 1 to 30, more preferably 1 to 20 carbons, particularly preferably 1 to 12 carbons; Diethyl phosphate amide, phenyl phosphate amide, etc.), hydroxy group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom, more preferably fluorine atom) ,

Cyano group, carboxy group, oxo group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, heterocyclic group (preferably 3 to 7-membered heterocyclic group, not aromatic heterocyclic but not aromatic) The hetero ring may be a hetero ring, and examples of the hetero atom constituting the hetero ring include a nitrogen atom, an oxygen atom and a sulfur atom Preferably, the carbon number is 0 to 30, more preferably a hetero ring having 1 to 12 carbon atoms. Specific examples thereof include imidazolyl, pyridyl, quinolyl, furyl, thienyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, carbazolyl, azepinyl and the like), silyl group (preferably having carbon atoms) A silyl group having 3 to 40, more preferably 3 to 30, and particularly preferably 3 to 24 carbon atoms; For example, trimethylsilyl, triphenylsilyl and the like), silyloxy groups (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, and particularly preferably 3 to 24 carbon atoms, for example, trimethylsilyloxy And triphenylsilyloxy etc.) and the like. These substituents may be further substituted by any one or more substituents selected from the above-mentioned Substituent Group Z.
In the present invention, when there is a plurality of substituents in one structural site, those substituents are linked to each other to form a ring, or condensed with a part or all of the above structural sites to be aromatic. It may form a ring or an unsaturated heterocyclic ring.

When the compound or substituent or the like contains an alkyl group, an alkenyl group or the like, these may be linear or branched, and may be substituted or unsubstituted. Further, when the aryl group, the heterocyclic group and the like are contained, they may be monocyclic or fused ring, and may be substituted or unsubstituted.
In the present specification, those which are described only as substituents are the ones referring to this substituent group Z unless otherwise specified, and when only the name of each group is described ( For example, in the case where only “alkyl group” is described), preferred ranges and specific examples in the corresponding group of this substituent group Z apply.

  The molecular weight of the polyimide compound used in the present invention can not generally be measured or determined in general because it is insolubilized in a solvent when it is a crosslinked film. As a precursor before crosslinking, the weight average molecular weight of the polyimide is preferably 10,000 to 1,000,000, more preferably 15,000 to 500,000, and still more preferably 20,000 to 200,000. It is.

  In the present specification, unless otherwise specified, the molecular weight and the degree of dispersion are values measured using a GPC (gel filtration chromatography) method, and the molecular weight is a polystyrene-equivalent weight average molecular weight. The gel packed in the column used in the GPC method is preferably a gel having an aromatic compound as a repeating unit, and examples thereof include a gel composed of a styrene-divinylbenzene copolymer. It is preferable to use 2 to 6 columns in a connected state. Examples of the solvent to be used include ether solvents such as tetrahydrofuran, and amide solvents such as N-methyl pyrrolidinone. The measurement is preferably performed at a solvent flow rate of 0.1 to 2 mL / min, and most preferably 0.5 to 1.5 mL / min. By performing the measurement within this range, the load on the device is not applied, and the measurement can be performed more efficiently. The measurement temperature is preferably 10 to 50 ° C, and most preferably 20 to 40 ° C. The column and carrier to be used can be appropriately selected according to the physical properties of the polymer compound to be measured.

(Synthesis of polyimide compound)
The polyimide compound used in the present invention can be synthesized by condensation polymerization of a bifunctional acid anhydride (tetracarboxylic acid dianhydride) having a specific structure and a diamine having a specific structure. As the method, for example, a general book (for example, Ikuo Imai and Takuo Yokota, “Latest Polyimide-Basics and Applications”, NTS Co., Ltd., August 25, 2010, p. , Etc.) can be implemented with appropriate reference.

  In the synthesis of the polyimide compound used in the present invention, at least one kind of tetracarboxylic acid dianhydride which is one of the raw materials is represented by the following formula (IV). It is preferable that all the tetracarboxylic dianhydrides used as a raw material are represented by following formula (IV).

  In formula (IV), R has the same meaning as R in formula (I-a) above, and the preferred range is also the same.

  Specific examples of the tetracarboxylic acid dianhydride that can be used in the present invention include those shown below.

  In addition, in the synthesis of the polyimide compound which can be used in the present invention, at least one kind of diamine compound which is another raw material is represented by the following formula (V).

Wherein ^(V), R ^3, m1 and ^{X a} has the same meaning as ^R 3, m1 and ^{X a} in each formula (I-a), thereof it is also the same preferable ranges.
Moreover, in addition to the diamine compound represented by said Formula (V) as a diamine compound used as a raw material in the synthesis | combination of the polyimide compound which can be used for this invention, following formula (VII-a) or following formula (VII-b) The diamine compound represented by these may be used.

Wherein (VII-a), ^{R 4} and l1 are each synonymous with ^{R 4} and l1 in the above formula (II-a). The diamine compound represented by Formula (V) is not contained in the diamine compound represented by Formula (VII-a).
Wherein ^{(VII-b), R 5} , R 6, X 4, m1 and n1 are the same meanings as ^{R 5, R 6, X 4} , m1 and n1 in the formula (II-b).

  As a diamine represented by a formula (VII-a) or (VII-b), what is shown below can be used, for example.

  The monomer represented by the above formula (IV) and the monomer represented by the above formula (V), (VII-a) or (VII-b) may be used in advance as an oligomer or prepolymer. The polyimide compound used in the present invention may be any of a block copolymer, a random copolymer and a graft copolymer.

The polyimide compound used in the present invention can be obtained by mixing each of the above-mentioned raw materials in a solvent and subjecting it to condensation polymerization in the usual manner as described above.
The above solvent is not particularly limited, but is an ester organic solvent such as methyl acetate, ethyl acetate or butyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, aliphatic such as dicyclopentanone or cyclohexanone Ketone organic solvents, ether organic solvents such as ethylene glycol dimethyl ether, dibutyl ether, tetrahydrofuran, methylcyclopentyl ether, dioxane etc., amide organics such as N-methyl pyrrolidone, 2-pyrrolidone, dimethylformamide, dimethylimidazolidinone, dimethylacetamide Examples thereof include solvents, sulfur-containing organic solvents such as dimethylsulfoxide and sulfolane. These organic solvents are suitably selected in the range which makes it possible to dissolve the reaction substrate tetracarboxylic acid dianhydride, the diamine compound, the polyamic acid which is the reaction intermediate, and the polyimide compound which is the final product. It is a thing. Preferably, an ester type (preferably butyl acetate), an aliphatic ketone type (preferably, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, diacetone alcohol, cyclopentanone, cyclohexanone), an ether type (diethylene glycol monomethyl ether, methyl cyclopentyl ether), an amide Solvents of a system (preferably N-methyl pyrrolidone) and a sulfur-containing system (dimethyl sulfoxide, sulfolane) are preferred. Moreover, these can be used combining 1 type, or 2 or more types of solvent.

  There is no particular limitation on the polymerization reaction temperature, and a temperature which can be usually employed in the synthesis of a polyimide compound can be employed. Specifically, it is preferably −50 to 250 ° C., more preferably −25 to 225 ° C., still more preferably 0 ° C. to 200 ° C., and particularly preferably 20 ° C. to 190 ° C.

  A polyimide compound is obtained by imidating the polyamic acid produced | generated by said polymerization reaction by carrying out the dehydration ring-closing reaction within a molecule | numerator. As a method of dehydrating and ring closing, a general book (for example, Ikuo Imai and Takuo Yokota, "Latest Polyimide-Basics and Applications", NTS Co., Ltd., August 25, 2010, p. 3 to 49, etc.) can be referred to. For example, a thermal imidization method of heating to 120 ° C. to 200 ° C. to remove by-produced water and removing it out of the system, or in the presence of a basic catalyst such as pyridine, triethylamine or DBU, acetic anhydride or dicyclohexyl Methods such as so-called chemical imidization using a dehydration condensation agent such as carbodiimide or triphenyl phosphite are suitably used.

Specific preferred examples of the polyimide compound are listed below, but the present invention is not limited thereto. When obtaining the crosslinked polyimide compound (crosslinked film) of the present invention, it is achieved by appropriately combining these polyimide compounds (polymers) and a crosslinking agent described later.

Next, preferable specific examples of the crosslinking agent which can be used in combination with the polymer of the present invention are listed below, but the present invention is not limited thereto.

  In the present invention, the polyimide compound may have a borate, phosphite or phosphonate (for example, the above formulas R-1 to R-8) structure in advance, and in this case, a crosslinking agent (not having these) The crosslinking may be carried out by the above formulas R-9 to R-13). Alternatively, the polyimide compound may be crosslinked with a crosslinking agent (the above formulas R-1 to R-8) having no borate, phosphite or phosphonate structure in the polyimide compound.

  In the present invention, the total concentration of tetracarboxylic acid dianhydride and diamine compound in the polymerization reaction solution of the polyimide compound is not particularly limited, but it is preferably 5 to 70% by mass, more preferably 5 to 50% by mass Is more preferable, and more preferably 5 to 30% by mass.

[Gas separation membrane]
(Gas separation composite membrane)
In the gas separation composite membrane, which is a preferred embodiment of the gas separation membrane of the present invention, a gas separation layer containing a specific polyimide compound is formed on the upper side of the gas permeable support layer. This composite membrane is the meaning that the coating liquid (dope) which makes the above-mentioned gas separation layer is applied to at least the surface of the porous support (herein, the term application includes the aspect attached to the surface by immersion) It is preferable to form by carrying out.
FIG. 1 is a longitudinal sectional view schematically showing a gas separation composite membrane 10 according to a preferred embodiment of the present invention. 1 is a gas separation layer, 2 is a support layer consisting of a porous layer. FIG. 2 is a cross-sectional view schematically showing a gas separation composite membrane 20 according to another preferred embodiment of the present invention. In this embodiment, in addition to the gas separation layer 1 and the porous layer 2, a non-woven fabric layer 3 is added as a support layer.
1 and 2 show an embodiment in which the permeate gas is enriched in carbon dioxide by selectively permeating carbon dioxide from a mixed gas of carbon dioxide and methane.

  In the present specification, "support layer upper side" means that another layer may be interposed between the support layer and the gas separation layer. In addition, regarding the expression of upper and lower, unless otherwise specified, the side to which the gas to be separated is supplied is referred to as “upper”, and the side from which the separated gas is discharged is referred to as “lower”.

  In the gas separation composite membrane of the present invention, the gas separation layer may be formed and disposed on the surface or the inner surface of the porous support (support layer), and at least on the surface, it is easily formed into a composite membrane. be able to. By forming the gas separation layer on at least the surface of the porous support, a composite membrane having the advantage of combining high separation selectivity with high gas permeability and mechanical strength can be obtained. The film thickness of the separation layer is preferably as thin as possible under the conditions of imparting high gas permeability while maintaining mechanical strength and separation selectivity.

  In the gas separation composite membrane of the present invention, the thickness of the gas separation layer is not particularly limited. The thickness of the gas separation layer is preferably 0.01 to 5.0 μm, and more preferably 0.05 to 2.0 μm.

The porous support (porous layer) that is preferably applied to the support layer is not particularly limited as long as it is for the purpose of meeting mechanical strength and high gas permeability. It may be a material. Preferably, it is a porous membrane of an organic polymer, and its thickness is 1 to 3000 μm, preferably 5 to 500 μm, and more preferably 5 to 150 μm. The pore structure of this porous membrane usually has an average pore diameter of 10 μm or less, preferably 0.5 μm or less, more preferably 0.2 μm or less. The porosity is preferably 20 to 90%, more preferably 30 to 80%.
Here, that the support layer has “gas permeability” means that carbon dioxide is supplied to the support layer (a film consisting of only the support layer) at a temperature of 40 ° C. with the total pressure on the gas supply side being 4 MPa. It means that the permeation rate of carbon dioxide is 1 × 10 ⁻⁵ cm ³ (STP) / cm ² · sec · cmHg (10 GPU) or more. Furthermore, the gas permeability of the support layer is such that the carbon dioxide permeation rate is 3 × 10 ⁻⁵ cm ³ (STP) when carbon dioxide is supplied at a total pressure on the gas supply side of 4 MPa at a temperature of 40 ° C. It is preferable that it is cm < ² > * sec * cmHg (30 GPU) or more, It is more preferable that it is 100 GPU or more, It is more preferable that it is 200 GPU or more. As materials for the porous membrane, conventionally known polymers such as polyolefin resins such as polyethylene and polypropylene, fluorine-containing resins such as polytetrafluoroethylene, polyvinyl fluoride and polyvinylidene fluoride, polystyrene, cellulose acetate, polyurethane And various resins such as polyacrylonitrile, polyphenylene oxide, polysulfone, polyether sulfone, polyimide and polyaramid. The shape of the porous membrane may be any shape such as a flat plate, a spiral, a tube, and a hollow fiber.

  In the gas separation composite membrane of the present invention, it is preferable that a support is formed in order to further impart mechanical strength to the lower part of the support layer forming the gas separation layer. Examples of such a support include woven fabric, non-woven fabric, net and the like, but non-woven fabric is suitably used in view of film forming property and cost. As the non-woven fabric, fibers made of polyester, polypropylene, polyacrylonitrile, polyethylene, polyamide or the like may be used alone or in combination. The non-woven fabric can be produced, for example, by forming main fibers and binder fibers uniformly dispersed in water with a circular net or a long net, and drying with a dryer. Moreover, it is also preferable to perform pressure heat processing by sandwiching the non-woven fabric between two rolls for the purpose of removing fluff and improving mechanical properties.

<Method for producing gas separation composite membrane>
Preferably, the method for producing a composite membrane of the present invention comprises applying a coating solution containing the above-mentioned polyimide compound onto a support to form a gas separation layer. Although content of the polyimide compound in a coating liquid is not specifically limited, It is preferable that it is 0.1-30 mass%, and it is more preferable that it is 0.5-10 mass%. When the content of the polyimide compound is too low, when forming a film on a porous support, the layer easily penetrates the lower layer, which increases the possibility of causing defects in the surface layer contributing to separation. In addition, when the content of the polyimide compound is too high, the film may be filled at a high concentration in the pores when forming a film on a porous support, and the permeability may be lowered. The gas separation membrane of the present invention can be appropriately produced by adjusting the molecular weight, structure, composition and solution viscosity of the polymer of the separation layer.

-Organic solvent-
The organic solvent used as the medium of the coating solution is not particularly limited, but hydrocarbon organic solvents such as n-hexane and n-heptane, ester organic solvents such as methyl acetate, ethyl acetate and butyl acetate, Lower alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, aliphatic ketones such as diacetone alcohol, cyclopentanone, cyclohexanone, ethylene glycol , Diethylene glycol, triethylene glycol, glycerin, propylene glycol, ethylene glycol monomethyl or monoethyl ether, propylene glycol methyl ether, dipropylene glycol methyl ether, tripez Ether compounds such as pyrene glycol methyl ether, ethylene glycol phenyl ether, propylene glycol phenyl ether, diethylene glycol monomethyl or monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl or monoethyl ether, dibutyl ether, tetrahydrofuran, methylcyclopentyl ether, dioxane, etc. Solvents, N-methylpyrrolidone, 2-pyrrolidone, dimethylformamide, dimethylimidazolidinone, dimethylsulfoxide, dimethylacetamide and the like can be mentioned. These organic solvents are suitably selected in the range that they do not adversely affect the support etc., but preferably they are ester (preferably butyl acetate), alcohol (preferably methanol, ethanol, isopropanol) , Isobutanol), aliphatic ketones (preferably, methyl ethyl ketone, methyl isobutyl ketone, diacetone alcohol, cyclopentanone, cyclohexanone), ethers (ethylene glycol, diethylene glycol monomethyl ether, methylcyclopentyl ether) are preferable, more preferably fat Family ketone type, alcohol type and ether type. Moreover, these can be used combining 1 type or 2 types or more.

<Other Layers Between Support Layer and Gas Separation Layer>
In the gas separation composite membrane of the present invention, another layer may be present between the support layer and the gas separation layer. A siloxane compound layer is mentioned as a preferable example of another layer. By providing the siloxane compound layer, the irregularities on the outermost surface of the support can be smoothed, and the separation layer can be easily thinned. As a siloxane compound which forms a siloxane compound layer, the thing in which a principal chain consists of polysiloxane, and the compound which has a siloxane structure and a non-siloxane structure in a principal chain are mentioned.
In the present specification, the term "siloxane compound" means an organopolysiloxane compound unless otherwise specified.

-Siloxane compound whose main chain is composed of polysiloxane-
As a siloxane compound which the principal chain consists of polysiloxane which can be used for a siloxane compound layer, 1 type (s) or 2 or more types of polyorganosiloxane represented by following formula (1) or (2) are mentioned. Also, these polyorganosiloxanes may form a crosslinking reaction product. As the cross-linking reaction, for example, a compound represented by the following formula (1) is crosslinked by a polysiloxane compound having a group capable of linking by reacting with the reactive group X ^S of the formula (1) at both ends And other forms of compounds.

In the formula (1), R ^S is a non-reactive group, and is preferably an alkyl group (preferably having 1 to 18 carbon atoms, more preferably an alkyl group having 1 to 12 carbon atoms) or an aryl group (preferably 6 to 6 carbon atoms). 15, more preferably an aryl group having 6 to 12 carbon atoms, still more preferably phenyl).
X ^S is a reactive group and is selected from a hydrogen atom, a halogen atom, a vinyl group, a hydroxyl group, and a substituted alkyl group (preferably having 1 to 18 carbon atoms, more preferably having 1 to 12 carbon atoms) It is preferably a group.
Y ^S and Z ^S are the above R ^S or X ^S.
m is a number of 1 or more, preferably 1 to 100,000.
n is a number of 0 or more, preferably 0 to 100,000.

Wherein ^{(2), X S, Y} S, Z S, R S, m and n are ^X S of each formula ^{(1), Y S, Z} S, R S, and m and n synonymous.

In the above formulas (1) and (2), when the non-reactive group R ^S is an alkyl group, examples of the alkyl group include methyl, ethyl, hexyl, octyl, decyl and octadecyl. . Also, if a non-reactive group R is a fluoroalkyl group, the fluoroalkyl group, _{e.g., -CH 2 CH 2 CF 3,} -CH 2 CH 2 C 6 F 13 and the like.

In the above formulas (1) and (2), when the reactive group X ^S is a substituted alkyl group, examples of the alkyl group include a hydroxyalkyl group having 1 to 18 carbon atoms and an aminoalkyl having 1 to 18 carbon atoms. Group, carboxyalkyl group having 1 to 18 carbon atoms, chloroalkyl group having 1 to 18 carbon atoms, glycidoxyalkyl group having 1 to 18 carbon atoms, glycidyl group, epoxycyclohexyl alkyl group having 7 to 16 carbon atoms, A C4-C18 (1-oxa cyclo butane 3-yl) alkyl group, a methacryloxy alkyl group, and a mercapto alkyl group are mentioned.
Preferably the number of carbon atoms of the alkyl group constituting the hydroxyalkyl groups is an integer of 1 to 10, for _example, -CH _{2 CH 2} CH ₂ OH.
Preferably the number of carbon atoms of the alkyl group constituting the amino alkyl group is an integer of 1 to 10, for _{example, -CH 2 CH 2 CH 2 NH 2} .
Preferably the number of carbon atoms of the alkyl group constituting the carboxyalkyl group is an integer of 1 to 10, for _example, -CH ₂ CH ₂ CH ₂ COOH.
Preferably the number of carbon atoms of the alkyl group constituting the chloroalkyl group is an integer of 1 to 10, for example, -CH 2 _Cl and the like.
The preferable carbon number of the alkyl group which comprises the said glycidoxy alkyl group is an integer of 1-10, for example, 3-glycidyl oxypropyl is mentioned.
The preferable carbon number of the said C7-C16 epoxy cyclohexyl alkyl group is an integer of 8-12.
The preferred carbon number of the C1-C18 (1-oxacyclobutan-3-yl) alkyl group is an integer of 4-10.
Preferred number of carbon atoms of the alkyl group constituting the methacryloxy group is an integer of 1 to 10, for _{example, -CH 2 CH 2 CH 2 -OOC} -C (CH 3) = CH 2 and the like.
Preferred number of carbon atoms of the alkyl group constituting the mercaptoalkyl group represents an integer of 1 to 10, for _example, -CH _{2 CH 2} CH ₂ SH.
Preferably, m and n are numbers such that the molecular weight of the compound is 5,000 to 1,000,000.

In the above formulas (1) and (2), a siloxane unit (wherein the number is m) having no reactive group and a reactive group-containing siloxane unit (wherein the structural unit is represented by the number represented by n) There is no particular limitation on the distribution of the constituent units represented by That is, in the formulas (1) and (2), (Si (R ^S ) (R ^S ) -O) units and (Si (R ^S ) (X ^S ) -O) units may be randomly distributed. .

-Compounds having a siloxane structure and a non-siloxane structure in the main chain-
As a compound which has a siloxane structure and a non-siloxane structure in a principal chain which can be used for a siloxane compound layer, the compound represented by following formula (3)-(7) is mentioned, for example.

Wherein ^{(3), R} S, m and n are respectively the same as ^R S, m and n in formula (1). R ^L is —O— or —CH ₂ —, and R ^S1 is a hydrogen atom or methyl. Both ends of Formula (3) are preferably an amino group, a hydroxyl group, a carboxy group, a trimethylsilyl group, an epoxy group, a vinyl group, a hydrogen atom or a substituted alkyl group.

  In Formula (4), m and n are respectively synonymous with m and n in Formula (1).

  In Formula (5), m and n are respectively synonymous with m and n in Formula (1).

  In Formula (6), m and n are respectively synonymous with m and n in Formula (1). It is preferable that an amino group, a hydroxyl group, a carboxy group, a trimethylsilyl group, an epoxy group, a vinyl group, a hydrogen atom, or a substituted alkyl group is bonded to both ends of the formula (6).

  In Formula (7), m and n are respectively synonymous with m and n in Formula (1). It is preferable that an amino group, a hydroxyl group, a carboxy group, a trimethylsilyl group, an epoxy, a vinyl group, a hydrogen atom, or a substituted alkyl group is bonded to both ends of the formula (7).

  In the above formulas (3) to (7), the siloxane structural unit and the non-siloxane structural unit may be distributed randomly.

  The compound having a siloxane structure and a non-siloxane structure in the main chain preferably contains 50 mol% or more, and more preferably 70 mol% or more of siloxane structural units based on the total number of moles of all repeating structural units. .

  The weight average molecular weight of the siloxane compound used in the siloxane compound layer is preferably 5,000 to 1,000,000 from the viewpoint of achieving both thin film formation and durability. The method of measuring the weight average molecular weight is as described above.

Further, preferable examples of the siloxane compound constituting the siloxane compound layer are listed below.
Polydimethylsiloxane, polymethylphenylsiloxane, polydiphenylsiloxane, polysulfone / polyhydroxystyrene / polydimethylsiloxane copolymer, dimethylsiloxane / methylvinylsiloxane copolymer, dimethylsiloxane / diphenylsiloxane / methylvinylsiloxane copolymer, methyl -3,3,3-trifluoropropylsiloxane / methylvinylsiloxane copolymer, dimethylsiloxane / methylphenylsiloxane / methylvinylsiloxane copolymer, diphenylsiloxane / dimethylsiloxane copolymer-terminated vinyl, polydimethylsiloxane-terminated vinyl, One or more selected from polydimethylsiloxane terminated H, and dimethylsiloxane / methylhydrosiloxane copolymer. In addition, the form which has formed the crosslinking reaction substance is also included in these.

In the composite film of the present invention, the thickness of the siloxane compound layer is preferably 0.01 to 5 μm, and more preferably 0.05 to 1 μm from the viewpoint of smoothness and gas permeability.
The gas permeability at 40 ° C. and 4 MPa of the siloxane compound layer is preferably 100 GPU or more, more preferably 300 GPU or more, and still more preferably 1000 GPU or more in carbon dioxide transmission rate.

(Gas separation asymmetric membrane)
The gas separation membrane of the present invention may be an asymmetric membrane. The asymmetric membrane can be formed by a phase conversion method using a solution containing a polyimide compound. The phase conversion method is a known method in which a polymer solution is brought into contact with a coagulating solution to form a film while phase conversion is performed, and in the present invention, a so-called dry-wet method is suitably used. In the dry-wet method, the solution on the surface of the polymer solution in the form of a film is evaporated to form a thin dense layer, and then immersed in a coagulating solution (a solvent compatible with the solvent of the polymer solution and the polymer is insoluble). This is a method of forming fine pores to form a porous layer by utilizing phase separation phenomenon occurring at that time, which is proposed by Rob Srilajan et al. (Eg, US Pat. No. 3,133,132). It is.

  In the gas separation asymmetric membrane of the present invention, the thickness of the surface layer contributing to gas separation, which is called a dense layer or a skin layer, is not particularly limited. The thickness of the surface layer is preferably 0.01 to 5.0 μm, and more preferably 0.05 to 1.0 μm, from the viewpoint of imparting practical gas permeability. On the other hand, the porous layer below the dense layer plays a role of lowering mechanical resistance while reducing resistance of gas permeability, and its thickness is particularly large as long as self-supporting property as an asymmetric membrane is given. It is not limited. The thickness is preferably 5 to 500 μm, more preferably 5 to 200 μm, and still more preferably 5 to 100 μm.

  The gas separation asymmetric membrane of the present invention may be a flat membrane or a hollow fiber membrane. The asymmetric hollow fiber membrane can be produced by a dry-wet spinning method. The dry-wet spinning method is a method of producing an asymmetric hollow fiber membrane by applying the dry-wet method from a spinning nozzle to a polymer solution having a hollow fiber shape. More specifically, the polymer solution is discharged from a nozzle into a hollow fiber target shape, and after passing through an atmosphere of air or nitrogen gas immediately after the discharge, the polymer is not substantially dissolved and compatible with the solvent of the polymer solution It is a method of immersing in a coagulating solution having the following to form an asymmetric structure, then drying it, and if necessary, heat treatment to produce a separation membrane.

  The solution viscosity of the solution containing the polyimide compound discharged from the nozzle is 2 to 17000 Pa · s, preferably 10 to 1500 Pa · s, particularly preferably 20 to 1000 Pa · s at the discharge temperature (eg 10 ° C.), hollow It is preferable because the shape after discharge such as thread can be stably obtained. Immersion in a coagulating solution is performed by immersing in a primary coagulating solution to coagulate to the extent that the shape of a membrane such as hollow fiber can be maintained, then wound on a guide roll, and then immersed in a secondary coagulating solution to sufficiently immerse the entire membrane. It is preferable to coagulate into It is efficient to dry the coagulated membrane after replacing the coagulating solution with a solvent such as hydrocarbon. The heat treatment for drying is preferably carried out at a temperature lower than the softening point or secondary transition point of the polyimide compound used.

<Protective layer on upper side of gas separation layer>
The gas separation membrane of the present invention may be provided with a siloxane compound layer in contact with the gas separation layer as a protective layer on the gas separation layer.
It is preferable that Si ratio of the said siloxane compound layer before and behind immersion in chloroform represented by following Numerical formula (I) exists in the range of 0.6-1.0.

Formula (I)
Si ratio = (Si-Kα X-ray intensity after chloroform immersion) / (Si-Kα X-ray intensity before chloroform immersion)

  For the Si ratio, the siloxane compound layer is immersed in chloroform at 25 ° C. for 12 hours, and the surface of the siloxane compound layer before and after this immersion is irradiated with X-rays, and the peak (2θ = X) of the Si-Kα X-ray (1.74 keV) It is calculated by measuring the intensity of 144.6 deg. The measuring method of Si-K alpha X-ray intensity is described, for example in Unexamined-Japanese-Patent No. 6-88792. When immersion in chloroform lowers the Si-Kα X-ray intensity as compared to before immersion, it means that a low molecular weight component is present and this is eluted. Therefore, after immersion in chloroform, the smaller the degree of decrease in the Si-Kα X-ray intensity, the more the polymer constituting the siloxane compound layer is made to mean that it is difficult to elute in chloroform.

When the Si ratio of the siloxane compound layer is in the range of 0.6 to 1.0, the siloxane compound can be densely and uniformly present in the layer, and film defects can be effectively prevented, and gas separation can be achieved. Performance can be further enhanced. In addition, it is possible to further suppress the use under high pressure, high temperature and high humidity conditions, and the plasticization of the gas separation layer due to an impurity component such as toluene.
0.7-1.0 are preferable, as for Si ratio of the siloxane compound layer in this invention, 0.75-1.0 are more preferable, 0.8-1.0 are more preferable, 0.85-1.0 Is particularly preferred.

In the siloxane compound layer in the present invention, each of the siloxane compounds is ^* -O-M-O- ^* , ^* -S-M-S- ^* , ^* -NR ^a C (= O)- ^* , ^* -NR ^b C _{^{(= O) NR b - *}} , * -O-CH 2 -O- *, * -S-CH 2 CH 2 - *, * -OC (= O) O- *, * -CH (OH) CH 2 _{^{OCO- *, 2 O- * * -CH}} (OH) CH, 2 S- * * -CH (OH) CH, * -CH (OH) CH 2 NR c - *, * -CH (CH 2 OH) CH _{^{2 OCO- *, * -CH (CH}} 2 OH) CH 2 O- *, * -CH (CH 2 OH) CH 2 S- *, * -CH (CH 2 OH) CH 2 N (R c) 2 - _{^{*, * -CH 2 CH 2 -}} *, * -C (= O) O - N + (R d) 3 - *, * -S It is preferable to have a structure linked via a linking group selected from O ₃ ^- N ⁺ (R ^e ) _3- ^* and ^* -PO ₃ ^- N ⁺ (R ^f ) _3- ^* .
In the formula, M represents a divalent to tetravalent metal atom. R ^a , R ^b , R ^c _, R ^d , R ^e and R ^{f each} represent a hydrogen atom or an alkyl group. ^{* Indicates} a linking site.

  Examples of the metal atom M include aluminum (Al), iron (Fe), beryllium (Be), gallium (Ga), vanadium (V), indium (In), titanium (Ti), zirconium (Zr), and copper. (Cu), cobalt (Co), nickel (Ni), zinc (Zn), calcium (Ca), magnesium (Mg), yttrium (Y), scandium (Sc), chromium (Cr), manganese (Mn), molybdenum Metal atoms selected from (Mo) and boron (B) can be mentioned, among which metal atoms selected from Ti, In, Zr, Fe, Zn, Al, Ga and B are preferable, and selected from Ti, In, and Al Metal atoms are more preferable, and Al is more preferable.

The alkyl group that can be taken as R ^a , R ^b , R ^c _, R ^d , R ^e and R ^f preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and still more preferably 1 to 1 carbon atoms. 7, particularly preferably an alkyl group having 1 to 4 carbon atoms. The alkyl group may be linear or branched, but is more preferably linear. Preferred specific examples of this alkyl group include, for example, methyl, ethyl, isopropyl, n-butyl, t-butyl, pentyl, hexyl, heptyl, octyl and 1-ethylpentyl.

  By having a structure in which the siloxane compounds are linked via the above-mentioned linking group, the Si ratio of the siloxane compound layer can be easily increased to within the range defined in the present invention.

  The reaction in which the siloxane compounds are linked via the linking group is described below.

< ^* -O-M-O- ^* >
The linking group ^* -O-M-O- ^* is, for example, a siloxane compound having a group (active hydrogen-containing group) having -OH, such as a hydroxy group, a carboxy group, a sulfo group, etc. It can be formed by ligand exchange reaction with the metal complex (crosslinking agent).

In formula, M is synonymous with the said metal atom M, and its preferable form is also the same. L ^L represents an alkoxy group, an aryloxy group, an acetylacetonato group, an acyloxy group, a hydroxy group or a halogen atom. y shows the integer of 2-4.
The alkoxy group that can be taken as L ^L preferably has 1 to 10 carbon atoms, more preferably 1 to 4 carbon atoms, and still more preferably 1 to 3 carbon atoms. Specific examples of the alkoxy group that can be taken as L ^L include, for example, methoxy, ethoxy, tert-butoxy and isopropoxy.
The carbon number of the aryloxy group that can be taken as L ^L is preferably 6 to 10, more preferably 6 to 8, and still more preferably 6 to 7. As a specific example of the aryloxy group which can be taken as L ^L , phenoxy, 4-methoxy phenoxy, and naphthoxy can be mentioned, for example.
The carbon number of the acyloxy group that can be taken as L ^L is preferably 2 to 10, more preferably 2 to 6, and still more preferably 2 to 4. Specific examples of the acyloxy group that can be taken as L ^L include, for example, acetoxy, propanoyloxy, pivaloyloxy and acetyloxy.
There is no restriction | limiting in particular in the halogen atom which can be taken as L ^L , A fluorine atom, a chlorine atom, a bromine atom, and an iodine atom are mentioned. Among them, chlorine atom is preferred.

  It is preferable that the metal complex represented by the said Formula (B) is soluble with respect to the organic solvent used for the coating liquid at the time of forming a siloxane compound layer. More specifically, the solubility of the metal complex represented by the above formula (B) in 100 g of tetrahydrofuran is preferably 0.01 to 10 g, and is preferably 0.1 to 1.0 g at 25 ° C. Is more preferred. When the metal complex represented by the said Formula (B) is soluble with respect to the said organic solvent, a more homogeneous metal bridge | crosslinking siloxane compound layer can be formed.

  Preferred specific examples of the metal complex represented by the above formula (B) include aluminum acetylacetonato, gallium acetylacetonato, indium acetylacetonato, zirconium acetylacetonato, cobalt acetylacetonato, calcium acetylacetonato, nickel acetyl Metal selected from acetonato, zinc acetylacetonato, magnesium acetylacetonato, ferric chloride, copper (II) acetate, aluminum isopropoxide, titanium isopropoxide, boric acid, and boron trifluoride diethyl ether complex And complexes.

It is as follows when an example of the said ligand exchange reaction is shown. The following example shows the case where the siloxane compound has a hydroxy group, but the same ligand exchange reaction proceeds even when the siloxane compound has an active hydrogen-containing group such as a carboxy group or a sulfo group, ^* - A linking group represented by O-MO- ^* is formed.

In the formula, R ^P represents a siloxane compound residue (that is, R ^P -OH represents a siloxane compound having a hydroxy group).
When M is a tetravalent metal atom (y = 4), R ^P —OH can usually coordinate up to four per one M (form of the above (a)). In the present invention, when M is a tetravalent metal atom, a form in which two R ^P —OHs are coordinated (form of the above (c)), and a form in which three RPs are coordinated (the above (b) ), and form) either in the form of four coordinating form ((a) above are also intended to be encompassed in the form having a linking group represented by ^* -O-M-O- ^*.
In addition, although not shown in the above formula, when the above-mentioned siloxane compound R ^P -OH is represented by R ^P1- (OH) _h (R ^P1 is a siloxane compound residue, h is an integer of 2 or more, ie 1 molecule Two or more OH present in one molecule of R ^P1- (OH) _h may be coordinated to one M) (when it is in a form having two or more hydroxy groups). This embodiment also ^* intended to be encompassed by embodiments having a ^-O-M-O-* a linking group represented.

When M is a trivalent metal atom (y = 3), R ^P -OH can usually coordinate up to three to one M (form of the above (d)). In the present invention, when M is a trivalent metal atom, a form in which two R ^P —OHs are coordinated (form of the above (e)), and a form in which three RPs are coordinated (the above (d) any form of) are also intended to be encompassed in the form having a linking group represented by ^* -O-M-O- ^*.
In addition, although not shown in the above formula, when the above-mentioned siloxane compound R ^P -OH is represented by R ^P1- (OH) _h (R ^P1 is a siloxane compound residue, h is an integer of 2 or more, ie 1 molecule Two or more OH present in one molecule of R ^P1- (OH) _h may be coordinated to one M) (when it is in a form having two or more hydroxy groups). This embodiment also ^* intended to be encompassed by embodiments having a ^-O-M-O-* a linking group represented.

When M is a divalent metal atom (y = 2), the form of the (f) is in the form having a linking group represented by the present invention defined by ^* -O-M-O- ^*.
In addition, although not shown in the above formula, when the above-mentioned siloxane compound R ^P -OH is represented by R ^P1- (OH) _h (R ^P1 is a siloxane compound residue, h is an integer of 2 or more, ie 1 molecule Two or more OH present in one molecule of R ^P1- (OH) _h may be coordinated to one M) (when it is in a form having two or more hydroxy groups). This embodiment also ^* intended to be encompassed by embodiments having a ^-O-M-O-* a linking group represented.

< ^* -S-M-S- ^* >
The above linked structure ^* -S-M-S- ^* can be formed, for example, by a ligand exchange reaction between a siloxane compound having a thiol group and the metal complex represented by the above formula (B). . This reaction is a reaction form in which R ^p -OH is replaced with R ^p -SH in the reaction for forming ^* -O-M-O- ^* described above. Since -SH is also an active hydrogen-containing group, a ligand exchange reaction can be performed in the same manner as described above.

< ^*- NR ^a C (= O)- ^* >
The above linking group ^* —NR ^a C (= O) — ^* is reacted, for example, with a siloxane compound having a carboxy group and a siloxane compound having an amino group in the presence of a dehydration condensation agent (eg, a carbodiimide compound). It can be formed by This reaction can be represented by the following formula.

R ^P -COOH + R ^P -N (R ^A ) ₂
R R ^P- C (= O)-NR ^A- R ^P + H ₂ O

In the above formula, R ^P represents a siloxane compound residue. In the left side, one of two R ^A linked to one N is a hydrogen atom, and the rest is a hydrogen atom or an alkyl group (that is, R ^{A on} the right side is a hydrogen atom or an alkyl group).
The linking group can also be formed by reacting a siloxane compound having a carboxy group with a compound having two or more amino groups as a crosslinking agent. Moreover, the said connection group can be formed also by making the siloxane compound which has an amino group, and the compound which has 2 or more of carboxy groups as a crosslinking agent react.

< ^*- NR ^b C (= O) NR ^b - ^* >
The linking group ^* -NR ^b C (= O) NR ^{b- *} can be formed, for example, by reacting a siloxane compound having an amino group with a chloroformate as a crosslinking agent. This reaction can be represented by the following formula.

2R ^P -N (R ^B ) ₂ + Cl-C (= O) -O-R ^Cl
P R ^P- R ^B N-C (= O)-NR ^B- R ^P + HCl + HO-R ^Cl

In the above formula, R ^P represents a siloxane compound residue, and R ^Cl represents an alcohol residue of chloroformate. One of the two R ^B is coupled to one of N in the left side is a hydrogen atom, the remainder is a hydrogen atom or an alkyl group (i.e., the right side of the R ^B is a hydrogen atom or an alkyl group).

_{^{<* -O-CH 2 -O- *}} >
The above linking group ^* -O-CH ₂ -O- ^* can be formed, for example, by reacting a siloxane compound having a hydroxy group with formaldehyde as a crosslinking agent. This reaction can be represented by the following formula.

2R ^P -OH + H-C (= O) -H
R R ^P -O-CH (O-R ^P ) -H + H ₂ O

In the above formula, R ^P represents a siloxane compound residue.

^{_{<* -S-CH 2 CH 2}} - *>
The linking group ^* -S-CH ₂ CH _2- ^* can be formed, for example, by reacting a siloxane compound having a thiol group with a siloxane compound having a vinyl group. This reaction can be represented by the following formula.

R ^P -SH + R ^P -CH = CH ₂
R R ^P -S-CH ₂ -CH ₂ -R ^P

In the above formula, R ^P represents a siloxane compound residue.
In addition, the said connection group can be formed also when making the siloxane compound which has a thiol group, and the compound which has 2 or more of vinyl groups as a crosslinking agent react. Moreover, the said connection group can be formed also by making the siloxane compound which has a vinyl group, and the compound which has 2 or more of thiol groups as a crosslinking agent react.

< ^*- OC (= O) O- ^* >
The linking group ^* -OC (= O) O- ^* can be formed, for example, by reacting a siloxane compound having a hydroxy group with a chloroformate as a crosslinking agent. This reaction can be represented by the following formula.

2R ^P -OH + Cl-C (= O)-O-R ^Cl
R R ^P -O-C (= O) -O-R ^P + HCl + HO-R ^Cl

In the above formula, R ^P represents a siloxane compound residue, and R ^Cl represents an alcohol residue of chloroformate.

< ^*- C (= O) O ^- N ⁺ (R ^d ) ₃ - ^* >
The above linking group ^* -C (= O) O ^- N ⁺ (R ^d ) _3- ^* can be formed, for example, by reacting a siloxane compound having a carboxy group with a siloxane compound having an amino group. . This reaction can be represented by the following formula.

R ^P -COOH + R ^P -N (R ^D ) ₂
R R ^P -CO-O ^-- N ⁺ H (R ^D ) ₂ -R ^P

In the above formula, R ^P represents a siloxane compound residue. R ^D represents a hydrogen atom or an alkyl group.
In addition, the said connection structure can be formed also by making the siloxane compound which has a carboxy group, and the compound which has 2 or more of amino groups as a crosslinking agent react. Moreover, the said connection group can be formed also by making the siloxane compound which has an amino group, and the compound which has 2 or more of carboxy groups as a crosslinking agent react.

_{^{<* -SO 3 - N + (}} R e) 3 - *>
The linking group _{^{* -SO 3 - N + (R}} e) 3 - * , for example, can be formed by reacting a siloxane compound having a sulfo group, a siloxane compound having an amino group. This reaction can be represented by the following formula.

R ^P -SO ₃ H + R ^P -N (R ^E ) ₂
R R ^P- SO _2- O ^-- N ⁺ H (R ^E ) _2- R ^P

In the above formula, R ^P represents a siloxane compound residue. R ^E represents a hydrogen atom or an alkyl group.
The above linking group can also be formed by reacting a siloxane compound having a sulfo group with a compound having two or more amino groups as a crosslinking agent. The above linking group can also be formed by reacting a siloxane compound having an amino group with a compound having two or more sulfo groups as a crosslinking agent.

_{^{<* -PO 3 H - N +}} (R f) 3 - *>
The connecting structure _{^{* -PO 3 H - N + (}} R f) 3 - * , for example, can be formed by reacting a siloxane compound having a phosphonic acid group, and a siloxane compound having an amino group. This reaction can be represented by the following formula.

R ^P -PO ₃ H ₂ + R ^P -N (R ^F ) ₂
R R ^P- P (= O) (OH)-O ^-- N ⁺ H (R ^F ) _2- R ^P

In the above formula, R ^P represents a siloxane residue. ^RF represents a hydrogen atom or an alkyl group.
The above linking group can also be formed by reacting a siloxane compound having a phosphonic acid group with a compound having two or more amino groups as a crosslinking agent. Moreover, the said connection group can also be formed by making the siloxane compound which has an amino group, and the compound which has 2 or more of sulfonic acid groups as a crosslinking agent react.

_{^{<* -CH (OH) CH 2}} OCO- *>
The linking group ^* -CH (OH) CH ₂ OCO- ^* can be formed, for example, by reacting a siloxane compound having an epoxy group and a siloxane compound having a carboxy group.
In addition, the above-mentioned linking group is produced by reacting a siloxane compound having an epoxy group with a compound having two or more carboxy groups as a crosslinking agent, or a siloxane compound having a carboxy group and an epoxy group as a crosslinking agent. It can also be formed by reacting with a compound having two or more.

_{^{<* -CH (OH) CH 2}} O- *>
The linking group ^* -CH (OH) CH ₂ O- ^* can be formed, for example, by reacting a siloxane compound having an epoxy group with a siloxane compound having a hydroxy group.
In addition, the above-mentioned linking group reacts a siloxane compound having an epoxy group with a compound having two or more hydroxy groups as a crosslinking agent, or a siloxane compound having a hydroxy group and an epoxy group as a crosslinking agent. It can also be formed by reacting with a compound having two or more.

_{^{<* -CH (OH) CH 2}} S- *>
The above linking group ^* -CH (OH) CH ₂ S- ^* can be formed, for example, by reacting a siloxane compound having an epoxy group with a siloxane compound having a thiol group.
In addition, the above-mentioned linking group is reacted with a siloxane compound having an epoxy group and a compound having two or more thiol groups as a crosslinking agent, or a siloxane compound having a thiol group and an epoxy group as a crosslinking agent. It can also be formed by reacting with a compound having two or more.

< ^* -CH (OH) CH ₂ NR ^c - ^* >
The linking group ^* -CH (OH) CH ₂ NR ^{c- *} can be formed, for example, by reacting a siloxane compound having an epoxy group with a siloxane compound having an amino group.
In addition, the above-mentioned linking group reacts a siloxane compound having an epoxy group and a compound having two or more amino groups as a crosslinking agent, or a siloxane compound having an amino group and an epoxy group as a crosslinking agent. It can also be formed by reacting with a compound having two or more.

^{_{<* -CH (CH 2 OH)}} CH 2 OCO- *>
The linking group ^{_{* -CH (CH 2 OH) CH}} 2 OCO- * in the formation of the above-mentioned _{^{* -CH (OH) CH 2 OCO-}} *, can be formed by replacing the epoxy group in an oxetanyl group.

^{_{<* -CH (CH 2 OH)}} CH 2 O- *>
The linking group ^{_{* -CH (CH 2 OH) CH}} 2 O- * in the formation of the above-mentioned _{^{* -CH (OH) CH 2 O-}} *, can be formed by replacing the epoxy group in an oxetanyl group.

^{_{<* -CH (CH 2 OH)}} CH 2 S- *>
The linking group ^{_{* -CH (CH 2 OH) CH}} 2 S- * , in the formation of the above-mentioned _{^{* -CH (OH) CH 2 S-}} *, can be formed by replacing the epoxy group in an oxetanyl group.

^{_{<* -CH (CH 2 OH)}} CH 2 NR c - *>
The linking group ^{_{* -CH (CH 2 OH) CH}} 2 NR c - * is above _{^{* -CH (OH) CH 2 NR}} c - * in the formation of, be formed by replacing the epoxy group in an oxetanyl group it can.

_{^{<* -CH 2 CH 2 - *}} >
The linking group ^* -CH ₂ CH _2- ^* can be formed, for example, by subjecting siloxane compounds having a vinyl group (such as a (meth) acryloyl group) to a polymerization reaction.
In the present invention, a structure linked via ^* -CH ₂ CH _2- ^* does not include a structure linked via ^* -S-CH ₂ CH _2- ^* .

  The siloxane compound layer may have one or two or more of the above connecting structures.

In the siloxane compound layer in the present invention, the linking structure of the siloxane compounds is the above ^* -O-MO- ^* , ^* -from the viewpoint of the reactivity for forming the linking structure and the chemical stability of the linking structure. _{^{S-M-S- *, *}} -O-CH 2 -O- *, * -S-CH 2 CH 2 - *, * -OC (= O) O- *, * -CH 2 CH 2 - *, And ^* -C (= O) O ^- N ⁺ (R ^d ) _3- ^* 1 type or 2 or more types of the connection structure through the connecting group chosen from ^* is desirable, ^* -OMO ^{* *} , ^{* -S-M-S- *, *} -O-CH 2 -O- * and _{^{* -S-CH 2 CH 2 -}} *, * -CH 2 CH 2 - * from connection structure via a linking group selected 1 type, or 2 or more types are more preferable, ^* -O-M-O- ^* and ^* -CH ₂ CH _2- ^{* are} selected 1 type or 2 types of linking structure via linking group are more preferable, ^* Linking structure via ^* -OMO ^{* *} and linking structure via ^* -CH ₂ CH _2- ^* It is further preferable to include.

The siloxane compound used as a raw material of the above-mentioned siloxane compound layer which is a protective layer (a siloxane compound before the formation of a linking structure via the above linking group) is particularly limited as long as it is a siloxane compound having a functional group giving the above linking structure There is no. Preferred examples of the polysiloxane compound include methacrylate-modified polydialkylsiloxane, methacrylate-modified polydiarylsiloxane, methacrylate-modified polyalkylaryl siloxane, thiol-modified polydialkylsiloxane, thiol-modified polydiarylsiloxane, and thiol-modified polyalkylaryl siloxane Hydroxy modified polydialkyl siloxane, hydroxy modified polydiaryl siloxane, hydroxy modified polyalkyl aryl siloxane, amine modified poly dialkyl siloxane, amine modified poly diaryl siloxane, amine modified poly alkyl aryl siloxane, vinyl modified poly dialkyl siloxane, vinyl modified poly diaryl siloxane , Vinyl-modified polyalkylaryl siloxanes, Voxy modified polydialkylsiloxane, carboxy modified polydiaryl siloxane, carboxy modified polyalkyl aryl siloxane, hydrosilyl modified polydialkyl siloxane, hydrosilyl modified polydiaryl siloxane, hydrosilyl modified polyalkyl aryl siloxane, epoxy modified polydialkyl siloxane, epoxy modified polydiaryl siloxane, One or more selected from epoxy-modified polyalkylaryl siloxanes, oxetanyl-modified polydialkylsiloxanes, oxetanyl-modified polydiarylsiloxanes, and oxetanyl-modified polyalkylaryl siloxanes.
Further, in the polysiloxane compounds exemplified above, the modification site by each functional group may be a terminal or a side chain. In addition, it is preferable that there are two or more denaturation sites in one molecule. Each functional group introduced by the above modification may further have a substituent.
There is no particular limitation on the amount ratio of the alkyl group to the aryl group in the above "polyalkylaryl siloxane". That is, the "polyalkylaryl siloxane" may have a dialkyl siloxane structure or a diaryl siloxane structure in its structure.
In the above-exemplified siloxane compounds, the carbon number of the alkyl group is preferably 1 to 10, more preferably 1 to 5, still more preferably 1 to 3, and particularly preferably methyl. Moreover, in the siloxane compound of the said illustration, 6-20 of carbon number of an aryl group is preferable, 6-15 are more preferable, 6-12 are more preferable, and phenyl is especially preferable.

The siloxane compound layer in the present invention preferably has at least one structure selected from the following (a) and (b).
(A) A structure having a structure represented by the following general formula (1a) and a structure represented by the following general formula (2a) or (3a)

(B) Structure represented by the following general formula (4a)

In the formula, R ^SL represents an alkyl group or an aryl group. L ^A represents a single bond or a divalent linking group. X ^A is ^{* -O-M 1 -O- *,} -S- * * -S-M 1, * -O-CH 2 -O- *, * -S-CH 2 CH 2 - *, * -OC The linking group is selected from (= O) O- ^* , ^* -CH ₂ CH _2- ^* , and ^* -C (= O) O ^- N ⁺ (R ^d ) _3- ^* . M ¹ represents Zr, Fe, Zn, B, Al or Ga, and R ^d represents a hydrogen atom or an alkyl group. a1 and b1 are integers of 2 or more (preferably 5 or more). " ^* " Shows a connection site. “**” indicates a linking site in a siloxane bond (ie, in the case of General Formulas (1a) to (3a), if ** is next to O atom, ** indicates a linking site to a Si atom, * When next to * is a Si atom, ** indicates an O atom and a linking site).
The terminal structure of the general formula (4a) is preferably a group selected from a hydrogen atom, a mercapto group, an amino group, a vinyl group, a carboxy group, an oxetane group, a sulfonic acid group and a phosphonic acid group.

When R ^SL and R ^{d each} represents an alkyl group, it is preferably an alkyl group having 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, still more preferably 1 to 3 carbon atoms, and particularly preferably methyl .
When the R ^SL is an aryl group, the carbon number thereof is preferably 6 to 20, more preferably 6 to 15, still more preferably 6 to 12, and particularly preferably a phenyl group.

If the ^{L A} is a divalent linking group, an alkylene group (preferably having from 1 to 10 carbon atoms, more preferably an alkylene group having 1 to 5 carbon atoms), an arylene group (having 6 to 20 carbon atoms, more preferably a carbon number 6-15 arylene group, more preferably the same meaning as ^{R SL} phenylene group), or ^-Si (R _SL) 2 -O- is preferred ^{(R SL} is the general formula (2a), a preferred form also the same. “O” in —Si (R ^SL ) ₂ —O— is linked to Si shown in the above general formula).

  It is preferable that the structure of said (a) has the repeating unit represented by following formula (5a) other than the structure represented by either of said General formula (1a)-(3a).

  It is also preferable that the repeating unit represented by the said Formula (5a) takes the structure where repeating units represented by the said Formula (5) mutually connected by the siloxane bond in a siloxane compound layer, and exists.

In the siloxane compound layer in the present invention, the content of the repeating unit represented by the above formula (5a) is preferably 0.01 to 0.55, and more preferably 0.03 to 0.40. More preferably, it is 0.05-0.25.
The content of the repeating unit represented by the formula (5a) was determined using the siloxane compound layer cut into 2.5 cm squares as a measurement sample, and the measurement sample was subjected to X-ray photoelectron spectroscopy (apparatus: Quantra SXM manufactured by Ulvac-PHI, Inc. Si2p (near 98 to 104 eV) under the conditions of X-ray source: Al-Kα ray (1490 eV, 25 W, 100 umφ), measurement area: 300 μm × 300 μm, Pass Energy 55 eV, Step 0.05 eV It can be determined by separating, quantifying and comparing the peaks of the component (103 eV) and the Q component (104 eV). That is, the fluorescent X-ray intensity [SA] of the Si-O binding energy peak of the repeating unit (Q component) represented by the formula (5a) and the structure (T component) other than the repeating unit represented by the formula (5a) [SA] / ([SA] + [ST]) is calculated based on the sum [ST] of the strengths of the Si-O bond energy peak of to give the content of the repeating unit represented by the formula (5a).

  In the present invention, the thickness of the siloxane compound layer is preferably 10 to 3,000 nm, and more preferably 100 to 1,500 nm.

(Applications and characteristics of gas separation membranes)
The gas separation membrane (composite membrane and asymmetric membrane) of the present invention can be suitably used as a gas separation and recovery method and a gas separation and purification method. For example, hydrogen, helium, carbon monoxide, carbon dioxide, hydrogen sulfide, oxygen, nitrogen, ammonia, sulfur oxides, nitrogen oxides, hydrocarbons such as methane and ethane, unsaturated hydrocarbons such as propylene, tetrafluoroethane, etc. The gas separation membrane can efficiently separate a specific gas from a gas mixture containing a gas such as a perfluoro compound of In particular, it is preferable to use a gas separation membrane for selectively separating carbon dioxide from a gas mixture containing carbon dioxide / hydrocarbon (methane).

In particular, when the gas to be separated and processed is a mixed gas of carbon dioxide and methane, the permeation rate of carbon dioxide at 40 ° C. and 5 MPa is preferably more than 20 GPU, more preferably more than 30 GPU, More preferably, it is 35 to 500 GPU. The permeation rate ratio of carbon dioxide to methane (R _CO2 / R _CH4 ) is preferably 15 or more, more preferably 20 or more, still more preferably 23 or more, and 25 to 50. Particularly preferred. R _CO2 indicates the permeation rate of carbon dioxide, and R _CH4 indicates the permeation rate of methane.
Note that 1 GPU is 1 × 10 ⁻⁶ cm ³ (STP) / cm ² · sec · cmHg.

(Other ingredients etc.)
Various polymer compounds can also be added to the gas separation layer of the gas separation membrane of the present invention in order to adjust the membrane physical properties. As the polymer compound, acrylic polymer, polyurethane resin, polyamide resin, polyester resin, epoxy resin, phenol resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl formal resin, shellac, vinyl resin, acrylic resin, rubber resin , Waxes and other natural resins can be used. Moreover, two or more of these may be used in combination.
Moreover, nonionic surfactant, cationic surfactant, and / or organic fluoro compound etc. can also be added for liquid physical-property adjustment.

  Specific examples of the surfactant include alkyl benzene sulfonate, alkyl naphthalene sulfonate, higher fatty acid salt, sulfonate of higher fatty acid ester, sulfate of higher alcohol ether, sulfonate of higher alcohol ether, higher alkyl Sulfonamide alkyl carboxylate, anionic surfactant such as alkyl phosphate, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, ethylene oxide adduct of acetylene glycol, Non-ionic surfactants such as ethylene oxide adduct of glycerin, polyoxyethylene sorbitan fatty acid ester, and other amphoteric surfaces such as alkyl betaine and amido betaine Active agents, silicone surface active agents, including such fluorine-based surfactant, can be appropriately selected from surfactants and derivatives thereof are known.

  In addition, a polymer dispersant may be included, and specific examples of the polymer dispersant include polyvinyl pyrrolidone, polyvinyl alcohol, polyvinyl methyl ether, polyethylene oxide, polyethylene glycol, polypropylene glycol, and polyacrylamide. Among them, polyvinyl pyrrolidone is preferably used.

  Although there is no restriction | limiting in particular in the conditions which form the gas separation membrane of this invention, -30-100 degreeC is preferable, -10-80 degreeC is more preferable, and 5-50 degreeC is especially preferable.

In the present invention, a gas such as air or oxygen may be made to coexist at the time of film formation, but it is desirable to be under an inert gas atmosphere.
In the gas separation membrane of the present invention, the content of the polyimide compound in the gas separation layer is not particularly limited as long as the desired gas separation performance can be obtained. From the viewpoint of further improving the gas separation performance, the content of the polyimide compound in the gas separation layer is preferably 20% by mass or more, more preferably 40% by mass or more, and 60% by mass or more. Is more preferable, and 70% by mass or more is particularly preferable. In addition, the content of the polyimide compound in the gas separation layer may be 100% by mass, but is usually 99% by mass or less.

[Separation method of gas mixture]
The gas separation method of the present invention is a method of separating a specific gas from a mixed gas of two or more components using the gas separation membrane of the present invention. The gas separation method of the present invention is a method including selectively permeating carbon dioxide from a mixed gas containing carbon dioxide and hydrocarbon gas (methane gas, butane gas, etc.). The pressure at the time of gas separation is preferably 0.5 to 10 MPa, more preferably 1 to 10 MPa, and still more preferably 2 to 7 MPa. The gas separation temperature is preferably -30 to 90 ° C, and more preferably 15 to 70 ° C. In the mixed gas containing carbon dioxide, methane gas and butane gas, the mixing ratio of carbon dioxide, methane gas and butane gas is not particularly limited. However, considering carbon dioxide and hydrocarbon gas (sum of methane gas and butane gas), carbon dioxide: carbonized Hydrogen gas = 1: 99-99: 1 (volume ratio) is preferable, and carbon dioxide: hydrocarbon gas = 5: 95-90: 10 is more preferable.

[Gas separation module or gas separation device]
A gas separation membrane module can be prepared using the gas separation membrane of the present invention. Examples of modules include spiral type, hollow fiber type, pleat type, tubular type, plate & frame type and the like.
Moreover, the gas separation composite membrane or the gas separation membrane module of the present invention can be used to obtain a gas separation apparatus having means for separating, recovering, or separating and purifying gas. The gas separation composite membrane of the present invention may be applied to, for example, a membrane used in combination with an absorbing liquid as described in JP-A-2007-297605 and / or a gas separation and recovery device as an absorption hybrid method.

  The present invention will be described in more detail based on the following examples, but the present invention is not limited by these examples.

[Composition example]
<Synthesis of Polyimide Compound (P-01)>

(Synthesis of Polyimide Compound (P-01))
In a 300 mL three-necked flask, 96.00 g of N-methyl pyrrolidone (NMP), 4.93 g (25 mmol) of 2,5-diaminophenol dihydrochloride, 1.85 g (25 mmol) of lithium carbonate are added, and a nitrogen stream 40 Stir for 30 minutes at ° C. After cooling to room temperature, 11.11 g (25 mmol) of 4,4 '-(hexafluoroisopropylidene) diphthalic anhydride was added, and the mixture was stirred for 30 minutes under a nitrogen stream. 47.98 g of toluene was added, and the mixture was heated to 180 ° C., stirred for 6 hours, and azeotropically distilled. After cooling to room temperature, it was diluted with 125.00 g of acetone, dropped into 1800.00 g of methanol, and the obtained polymer was suction filtered. The obtained polymer was washed with 200 g of methanol and air-dried at 70 ° C. to obtain 13.15 g of a polymer compound (P-01) consisting of the above structural units (repeating units).

<Synthesis of Polyimide Compound (P-02)>
In the synthesis of the above polyimide compound (P-01), the above polyimide compound (3) except that 3,3′-dihydroxybenzidine (5.41 g) was used instead of 2,5-diaminophenol dihydrochloride (4.93 g) A polyimide compound (P-02) (13 g) was obtained in the same manner as in the synthesis of P-01).

Polyimide compound (P-02)

Polyimide compound (P-06), (P-07)
Polymer compounds (P-06) and (P-07) were synthesized with reference to the description in U.S. Patent Publication No. US2015 / 0093510.

<Comparative polymer (C-01)>
The comparative polymer (C-01) was synthesized with reference to the description of US published patent US2015 / 0093510.

Comparative polymer (C-01)

<Comparative polymer (C-02)>
The comparative polymer (C-02) was synthesized with reference to the description of WO 2010/143647.

Comparative polymer (C-02)

Example 1 Preparation of Composite Membrane <Preparation of PAN Porous Membrane with Smooth Layer>
(Preparation of radiation curable polymer having dialkyl siloxane group)
In a 150 mL three-necked flask, 39 g of UV 9300 (manufactured by Momentive), 10 g of X-22-162C (manufactured by Shin-Etsu Chemical Co., Ltd.), DBU (1,8-diazabicyclo [5.4.0] undec-7-ene) 0. 007 g was added and dissolved in 50 g of n-heptane. This was maintained at 95 ° C. for 168 hours to obtain a radiation curable polymer solution having a poly (siloxane) group (viscosity 22.8 mPa · s at 25 ° C.).

(Preparation of polymerizable radiation curable composition)
5 g of the above radiation curable polymer solution was cooled to 20 ° C. and diluted with 95 g of n-heptane. To the resulting solution, 0.5 g of a photopolymerization initiator UV9380C (manufactured by Momentive) and 0.1 g of Organix TA-10 (manufactured by Matsumoto Fine Chemical Co., Ltd.) were added to obtain a polymerizable radiation curable composition. Prepared.

(Application of polymerizable radiation curable composition to porous support, formation of smooth layer)
After spin-coating the above-mentioned polymerizable radiation-curable composition using a PAN (polyacrylonitrile) porous film (a polyacrylonitrile porous film is present on a non-woven fabric and the film thickness is about 180 μm including the non-woven fabric) as a support, After UV treatment (Fusion UV System, Light Hammer 10, D-bulb) was performed under UV treatment conditions of UV intensity 24 kW / m and treatment time 10 seconds, it was dried. Thus, a 1 μm thick smooth layer having a dialkylsiloxane group was formed on the porous support.

<Fabrication of composite film>
The gas separation composite membrane shown in FIG. 2 was produced (the smooth layer is not shown in FIG. 2).
In a 30 ml brown vial, 0.08 g of the polyimide compound (P-01) and, as a cross-linking agent, ortho boric acid (manufactured by Wako Pure Chemical Industries, Ltd.) (0.5 mg, 5 mol%) mixed with 7.92 g of tetrahydrofuran for 30 minutes After stirring, the smooth layer was spin-coated on the PAN porous film provided with the smooth layer to form a gas separation layer containing a polyimide compound (P-01), to obtain a composite film. The thickness of the polyimide compound (P-01) layer was about 100 nm, and the thickness of the polyacrylonitrile porous film was about 180 μm including the non-woven fabric.
The molecular weight cut off of these polyacrylonitrile porous membranes was 100,000 or less. Further, the permeability of carbon dioxide at 40 ° C. and 5 MPa of this porous membrane was 25,000 GPU.

[Preparation of composite film] (with protective layer)
A protective layer was provided on the surface of the gas separation layer of the composite membrane prepared above according to the following procedure.
Vinyl Q resin (Gelest, product no. VQM-135) (10 g), hydrosilyl PDMS (Gelest, product no. HMS-301) (1 g), Karstedt catalyst (Aldrich, product no. 479 527) (5 mg), heptane A mixed solution obtained by mixing (90 g) was spin-coated on the surface of the gas separation layer of the composite membrane prepared in Example 1, dried at 80 ° C. for 5 hours, and cured. Thus, a gas separation composite membrane having a 500 nm-thick siloxane compound layer on the gas separation layer was obtained.

[Example 2 to Example 31] Preparation of Composite Membrane In <Preparation of Composite Membrane> in Example 1 above, the polyimide compound (P-P (P-01)) was mixed with 0.08 g of tetrahydrofuran and 7.92 g of tetrahydrofuran. Example 1 and Example 1 with the exception that -01) was changed as described in Table 1, and except that orthoboric acid (manufactured by Wako Pure Chemical Industries, Ltd.) was changed as described in Table 1 as a crosslinking agent. A composite membrane was produced in the same manner.

Comparative Examples 1 and 2 Preparation of Composite Membranes Composite membranes of Comparative Examples 1 and 2 were fabricated in the same manner as in Example 1 except that the cross-linking agent orthoboric acid was omitted.

Comparative Examples 3 to 4 Preparation of Hollow Fiber Membrane The procedure was carried out except that the above comparative polymer (C-01) or (C-02) was used instead of the above polyimide compound (P-01) or (P-02). In the same manner as in Example 1, hollow fiber membranes of Comparative Examples 3 to 4 were produced.

[Test Example 1] Evaluation of CO ₂ permeation rate and gas separation selectivity of gas separation membrane-1
The gas separation performance was evaluated as follows using the gas separation membranes (composite membranes) of the respective Examples and Comparative Examples.
The gas separation membrane was cut into a diameter of 5 cm together with the porous support (support layer) to prepare a permeation test sample. A mixed gas of carbon dioxide (CO ₂ ): methane gas (CH ₄ ): butane gas (C ₄ H ₁₀ ) at a ratio of 10:80:10 (volume ratio) is supplied on the gas supply side using a gas permeability measurement device manufactured by GTR Tech Co., Ltd. The total pressure was adjusted to 5 MPa, flow rate 500 mL / min, 40.degree. C. and supplied. The permeated gas was analyzed by gas chromatography. The gas permeability of the membranes was compared by calculating the gas permeation rate as the gas permeability (Permeance). The unit of the gas permeability (gas permeation rate) was expressed by GPU (GPE) unit [1 GPU = 1 × 10 ⁻⁶ cm ³ (STP) / cm ² · sec · cmHg]. Gas separation selectivity, permeation rate _{R CO2} ratio of CO ₂ to permeation rate _{R CH4} of CH ₄ of the film _(R CO2 _/ R _CH4), or _the transmission of CO ₂ with respect to the penetration rate _{R C4H10} of C _{4 H 10} Calculated as the ratio of rate R _CO2 (R _CO2 / R _{C4 H10} ).

Test Example 2 Toluene Exposure Test The gas separation membrane prepared in each of the above Examples and Comparative Examples was placed in a stainless steel container containing a petri dish covered with a toluene solvent to form a closed system. Then, after storing for 10 minutes under 25 ° C. conditions, the gas separation membrane was cut to a diameter of 5 cm in the same manner as in [Test Example 1] above, and a permeation test sample was produced to evaluate the gas separation performance. By exposure to toluene, the plasticization resistance of the gas separation membrane to impurity components such as benzene, toluene, and xylene can be evaluated.

Sample error rate [Evaluation of film formability]
Fifty samples of each of the gas separation membranes were prepared by the method described in each of the above Examples and Comparative Examples, and the hydrogen permeability of this 50 samples was measured, and the hydrogen permeability was 1 × 10 ⁶ ml / m ² · 24 h A sample exceeding atm was judged as a film with pinholes (sample error), and the sample error rate was determined from the following equation. Based on this sample error rate, the film forming property was evaluated according to the following evaluation criteria.
Sample error rate (%) = 100 × [number of sample errors / 50]
(Evaluation standard for film formation)
A: Error rate 5% or less B: Error rate 5% or more and 20% or less C: Error rate 20% or more

  The results of the above test examples are shown in Tables 1-1 and 1-2 below.

  From the above results, it was found that an excellent gas separation method, a gas separation module, and a gas separation apparatus provided with this gas separation module can be provided by using the gas separation membrane of the present invention.

1 gas separation layer 2 porous layer 3 non-woven fabric layer 10, 20 gas separation composite membrane

Claims (13)

A gas separation membrane comprising a crosslinked polyimide compound, wherein the crosslinked polyimide compound has a crosslinked structure via at least one connecting group selected from the group consisting of the following (A-1) to (A-12): Has a gas separation membrane.

In the above formulae, R ^a , R ^b and R ^c each independently represent a hydroxyl group, a halogen atom, an alkoxy group or an aryloxy group. The gas separation membrane according to claim 1, wherein the linking group is at least one selected from the group consisting of (B-1) to (B-6) below.

The gas separation membrane according to claim 1, wherein the crosslinked polyimide compound contains at least one of repeating units represented by formula (I-a).

In formula (I-a), R represents a tetravalent group represented by any of the following formulas (I-1) to (I-28). R ³ represents a substituent. m1 is an integer of 0 to 3. X ^a represents -B (OH) -O-, -P (= O) (OH) -O- or -P (OH) -O-.
Here, X ^{1 to} X ^{3 each} represent a single bond or a divalent linking group, L represents -CH = CH- or -CH _2- , R ¹ and R ^{2 each} represent a hydrogen atom or a substituent, and * represents a formula ( The binding site to the carbonyl group in I-a) is shown.

The gas separation membrane according to claim 3, wherein R in the above formula (I-a) is represented by the following formula (I-a1).

The gas separation membrane according to any one of claims 1 to 4, wherein the crosslinked polyimide compound contains a repeating unit represented by the following formula (I-a2).

In formula (I-a2), R ^I ₄ represents a hydrogen atom, an alkyl group or a halogen atom. X ^a represents a group selected from -B (OH) -O-, -P (= O) (OH) -O- or -P (OH) -O-.   The gas separation membrane according to any one of claims 1 to 5, wherein the gas separation membrane is a gas separation composite membrane having the gas separation layer on the upper side of a gas permeable support layer.   The gas separation membrane according to claim 6, wherein the support layer comprises a porous layer on the gas separation layer side and a non-woven fabric layer on the opposite side thereof. When the gas to be separated and processed is a mixed gas of carbon dioxide and methane, the permeation rate of carbon dioxide at 40 ° C. and 5 MPa is more than 20 GPU, and the permeation rate ratio of carbon dioxide to methane (R _CO2 / R _CH4 ) Is 15 or more, The gas separation membrane of any one of Claims 1-7. When the gas to be separated and processed is a mixed gas of carbon dioxide and butane, the permeation rate of carbon dioxide at 40 ° C. and 5 MPa is more than 20 GPU, and the permeation rate ratio of carbon dioxide to butane (R _CO2 / R _{C4 H10} ) Is 40 or more, The gas separation membrane of any one of Claims 1-7.   The gas separation membrane according to any one of claims 1 to 9, which is used to selectively permeate carbon dioxide from a gas containing carbon dioxide and a hydrocarbon gas.   A gas separation module comprising the gas separation membrane according to any one of claims 1 to 10.   A gas separation apparatus comprising the gas separation module according to claim 11.   A gas separation method using the gas separation membrane according to any one of claims 1 to 9.

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