Gas separation membrane

Abstract

The present invention relates to a gas separation membrane for separating carbon dioxide from a gas mixture containing carbon dioxide, the gas separation membrane including a polycarbonate-polyorganosiloxane copolymer (A), the polycarbonate-polyorganosiloxane copolymer (A) including a polycarbonate block (A-1) including only repetition of a structure unit represented by the general formula (I) and a polyorganosiloxane block (A-2) including repetition of a structure unit represented by the general formula (II), wherein the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass to 70% by mass inclusive. [In the formulas, R1, R2, R3, R4, X, a, and b are as defined in the specification.]

Description

Gas separation membrane

[0001] The present invention relates to gas separation membranes, the use of polymeric membranes, and methods for separating carbon dioxide from gas mixtures containing carbon dioxide.

[0002] Carbon dioxide contained in exhaust gases from power plants, factories, etc. is thought to be one of the causes of global warming. Therefore, various methods for separating and recovering carbon dioxide from exhaust gases have been studied. Patent Document 1 discloses a gas-permeable membrane, which is a polymer with a specific structure whose main chain is a siloxane bond (-Si-O-Si-), as a polymer membrane with high gas permeability.

[0003] Furthermore, polycarbonate-polyorganosiloxane copolymers (hereinafter sometimes abbreviated as "PC-POS copolymers") have attracted attention due to their excellent properties, such as high impact resistance, chemical resistance, and flame retardancy. Therefore, they are expected to be widely used in various fields, including electrical and electronic equipment and the automotive industry. In particular, they are being used extensively in housings for mobile phones, mobile PCs, digital cameras, video cameras, power tools, and other everyday items. However, the application of polycarbonate-polyorganosiloxane copolymers as gas separation membranes for separating carbon dioxide has not yet been considered.

[0004] Japanese Patent Application Publication No. 2018-15678

[0005] The technology disclosed in Patent Document 1 was insufficient in selectivity and permeation rate for carbon dioxide gas. Furthermore, the mechanical strength of the gas-permeable membrane was insufficient. The present invention relates to a gas separation membrane for separating carbon dioxide from a mixed gas containing carbon dioxide, which has excellent carbon dioxide selectivity and permeation rate and also has excellent mechanical strength.

[0006] The present inventors have found that the above-mentioned problems can be solved by a gas separation membrane containing a specific polycarbonate-polyorganosiloxane copolymer. Specifically, the present invention relates to the following [1] to [8]: [1] A gas separation membrane for separating carbon dioxide from a mixed gas containing carbon dioxide, the gas separation membrane comprising a polycarbonate-polyorganosiloxane copolymer (A), the polycarbonate-polyorganosiloxane copolymer (A) comprising a polycarbonate block (A-1) consisting only of repeating structural units represented by the following general formula (I) and a polyorganosiloxane block (A-2) containing repeating structural units represented by the following general formula (II), and the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass or more and 70% by mass or less.

[0007]

[0008] [In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO2-, -O-, or -CO-. R 3 and R 4 each independently represent hydrogen, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. a and b each independently represent an integer of 0 to 4.] [2] The gas separation membrane according to [1], wherein the average chain length n of the polyorganosiloxane block (A-2) is 20 to 150. [3] The gas separation membrane according to [1] or [2], wherein a and b in the general formula (I) are 0, and X is an isopropylidene group. [4] R in the general formula (II) 3 and R 4[5] The gas separation membrane according to any one of [1] to [3], wherein the product of the carbon dioxide permeability coefficient (unit: Barrer) and the membrane thickness (unit: μm) is 5.0 × 10 ３ The gas separation membrane according to any one of [1] to [4], wherein the mixed gas containing carbon dioxide is an exhaust gas. [6] The gas separation membrane according to any one of [1] to [5], wherein the mixed gas containing carbon dioxide is an exhaust gas. [7] Use of a polymer membrane containing a polycarbonate-polyorganosiloxane copolymer (A) for separating carbon dioxide from a mixed gas containing carbon dioxide, wherein the polycarbonate-polyorganosiloxane copolymer (A) contains a polycarbonate block (A-1) consisting only of repeating structural units represented by the following general formula (I) and a polyorganosiloxane block (A-2) containing repeating structural units represented by the following general formula (II), wherein the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass or more and 70% by mass or less.

[0009]

[0010] [In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO2-, -O-, or -CO-. R 3 and R 4each independently represent hydrogen, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. a and b each independently represent an integer of 0 to 4.] [8] A method for separating carbon dioxide from a gas mixture containing carbon dioxide, comprising a step of contacting the gas mixture containing carbon dioxide with a gas separation membrane, wherein the gas separation membrane comprises a polycarbonate-polyorganosiloxane copolymer (A), the polycarbonate-polyorganosiloxane copolymer (A) comprises a polycarbonate block (A-1) consisting only of repeating structural units represented by the following general formula (I), and a polyorganosiloxane block (A-2) containing repeating structural units represented by the following general formula (II), and the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass or more and 70% by mass or less.

[0011]

[0012] [In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO2-, -O-, or -CO-. R 3 and R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. a and b each independently represent an integer of 0 to 4.

[0013] According to the present invention, it is possible to provide a gas separation membrane for separating carbon dioxide from a gas mixture containing carbon dioxide, which has excellent carbon dioxide selectivity and permeability, as well as excellent mechanical strength. Furthermore, by applying this technology, it is possible to provide the use of a polymer membrane and a method for separating carbon dioxide from a gas mixture containing carbon dioxide.

[0014] The gas separation membrane of the present invention is a gas separation membrane for separating carbon dioxide from a mixed gas containing carbon dioxide, the gas separation membrane comprising a polycarbonate-polyorganosiloxane copolymer (A), the polycarbonate-polyorganosiloxane copolymer (A) comprising a polycarbonate block (A-1) consisting solely of repeating structural units represented by the following general formula (I) and a polyorganosiloxane block (A-2) comprising repeating structural units represented by the following general formula (II), and the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass or more and 70% by mass or less.

[0015] [In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO2-, -O-, or -CO-. R 3 and R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. a and b each independently represent an integer of 0 to 4.

[0016] The gas separation membrane of the present invention will be described in detail below. In this specification, the definitions that are considered to be preferable can be adopted arbitrarily, and a combination of preferable definitions can be considered more preferable. In this specification, the expression "XX to YY" means "XX or more and YY or less."

[0017] [Gas Separation Membrane] The gas separation membrane of the present invention is a gas separation membrane for separating carbon dioxide from a mixed gas containing carbon dioxide, comprising a specific polycarbonate-polyorganosiloxane copolymer (A). <Polycarbonate-Polyorganosiloxane Copolymer (A)> The gas separation membrane of the present invention comprises a polycarbonate block (A-1) consisting solely of repeating structural units represented by the following general formula (I) and a polyorganosiloxane block (A-2) containing repeating structural units represented by the following general formula (II), in which the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass or more and 70% by mass or less.

[0018]

[0019] [In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO2-, -O-, or -CO-. R 3 and R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. a and b each independently represent an integer of 0 to 4.

[0020] (Polycarbonate Block (A-1)) The polycarbonate block (A-1) consists solely of repeating structural units represented by the above general formula (I).

[0021] In the above general formula (I), R 1 and R 2 The halogen atoms independently represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 1 and R 2Examples of alkyl groups that R each independently represent include methyl, ethyl, n-propyl, isopropyl, various butyl groups (the term "various" includes linear and branched groups, and the same applies hereinafter in the specification), various pentyl groups, and various hexyl groups. 1 and R 2 The alkoxy groups independently represented by the formula (I) include those having the above alkyl group as the alkyl group moiety.

[0022] Examples of the alkylene group represented by X include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a hexamethylene group, and an alkylene group having 1 to 5 carbon atoms is preferred. Examples of the alkylidene group represented by X include an ethylidene group and an isopropylidene group. Examples of the cycloalkylene group represented by X include a cyclopentanediyl group, a cyclohexanediyl group, and a cyclooctanediyl group, and an alkylene group having 5 to 10 carbon atoms is preferred. Examples of the cycloalkylidene group represented by X include a cyclohexylidene group, a 3,5,5-trimethylcyclohexylidene group, and a 2-adamantylidene group, and an alkylidene group having 5 to 10 carbon atoms is preferred, and an alkylidene group having 5 to 8 carbon atoms is more preferred. The aryl moiety of the aryl alkylene group represented by X includes aryl groups having 6 to 14 ring carbon atoms such as a phenyl group, a naphthyl group, a biphenyl group, and an anthryl group, and the alkylene group includes the alkylenes described above. The aryl moiety of the aryl alkylidene group represented by X includes aryl groups having 6 to 14 ring carbon atoms such as a phenyl group, a naphthyl group, a biphenyl group, and an anthryl group, and the alkylidene group includes the alkylidene groups described above.

[0023] a and b each independently represent an integer of 0 to 4, preferably 0 to 2, and more preferably 0 or 1. Among these, preferably a and b are 0 and X is a single bond, an alkylene group having 1 to 8 carbon atoms, or an alkylidene group having 2 to 8 carbon atoms, more preferably a and b are 0 and X is an alkylidene group having 3 carbon atoms, and even more preferably a and b are 0 and X is an isopropylidene group.

[0024] The polycarbonate-polyorganosiloxane copolymer (A) preferably contains substantially no polycarbonate blocks other than the polycarbonate block (A-1). The polycarbonate block refers to a block structure containing repeating structural units represented by the following general formula (V):

[0025]

[0026] [In the formula, R 100 represents an organic group. 100 preferably represents a divalent aliphatic hydrocarbon group having 2 to 40 carbon atoms, a divalent alicyclic hydrocarbon group having 3 to 40 carbon atoms, or a divalent aromatic hydrocarbon group having 6 to 20 carbon atoms, and these groups may be substituted with a substituent and may contain at least one atom selected from the group consisting of an oxygen atom, a nitrogen atom, a sulfur atom, and a halogen atom.]

[0027] Examples of polycarbonate blocks that do not constitute the polycarbonate block (A-1) include polycarbonate blocks obtained using dihydroxydiarylfluorenes such as 9,9-bis(4-hydroxyphenyl)fluorene (also referred to as "BFL") and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene (also referred to as "BCFL") as dihydric phenol compounds. "Substantially free" means that the content of polycarbonate blocks other than the polycarbonate block (A-1) in the polycarbonate-polyorganosiloxane copolymer (A) is preferably 5% by mass or less, more preferably 1% by mass or less, even more preferably 0.5% by mass or less, and even more preferably 0% by mass, based on the total polycarbonate blocks. In other words, the content of the polycarbonate block (A-1) in all polycarbonate blocks is preferably 95% by mass or more, more preferably 99% by mass or more, even more preferably 99.5% by mass or more, and even more preferably 100% by mass.

[0028] (Polyorganosiloxane Block (A-2)) The polyorganosiloxane block (A-2) is a block structure present between the two most adjacent polycarbonate bonds on the main chain of the polycarbonate-polyorganosiloxane copolymer (A), and contains at least one repeat of the structural unit represented by the above general formula (II). 3 and R 4 The halogen atoms independently represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 3 and R 4 Examples of alkyl groups that R each independently represent include methyl, ethyl, n-propyl, isopropyl, various butyl groups, various pentyl groups, and various hexyl groups. 3 and R 4 The alkoxy groups each independently represent include those in which the alkyl group moiety is the above-mentioned alkyl group. 3 and R 4 Examples of the aryl group that each R represents independently include a phenyl group and a naphthyl group. 3 and R 4 are each preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and more preferably a methyl group.

[0029] Average Chain Length of Polyorganosiloxane Block (A-2) The average chain length n of the polyorganosiloxane block (A-2) contained in the polycarbonate-polyorganosiloxane copolymer (A) is preferably 20 to 150, more preferably 25 to 90, even more preferably 30 to 50, and even more preferably 35 to 45. If the average chain length is within the above range, a gas separation membrane having superior carbon dioxide selectivity and permeation amount, as well as mechanical strength, can be obtained. The average chain length of the polyorganosiloxane block (A-2) refers to the number of —SiR groups contained in the polyorganosiloxane block (A-2) that are present between the two most adjacent polycarbonate bonds on the main chain of the polycarbonate-polyorganosiloxane copolymer (A). ３ R４ The average number of repeating units represented by the general formula (II) contained in the polyorganosiloxane block (A-2) is n-1. The average chain length n of the polyorganosiloxane block (A-2) contained in the polycarbonate-polyorganosiloxane copolymer (A) is calculated by nuclear magnetic resonance (NMR) measurement.

[0030] - Content of polyorganosiloxane block (A-2) The content of polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) (also referred to as the polyorganosiloxane amount) is 20% by mass or more and 70% by mass or less. If the polyorganosiloxane amount in the polycarbonate-polyorganosiloxane copolymer (A) is within the above range, a gas separation membrane having excellent carbon dioxide selectivity and permeation rate, as well as mechanical strength, can be obtained. In one preferred embodiment of the present invention, the content of polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is preferably 30% by mass or more and 70% by mass or less, more preferably 35% by mass or more and 65% by mass or less, and even more preferably 40% by mass or more and 60% by mass or less. If the amount of polyorganosiloxane in the polycarbonate-polyorganosiloxane copolymer (A) is within the above range, a gas separation membrane having excellent carbon dioxide selectivity and permeation rate, as well as mechanical strength, can be obtained. In another preferred embodiment of the present invention, the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is preferably 20% by mass or more and 60% by mass or less, more preferably 20% by mass or more and 50% by mass or less, and even more preferably 20% by mass or more and 30% by mass or less. If the amount of polyorganosiloxane in the polycarbonate-polyorganosiloxane copolymer (A) is within the above range, a gas separation membrane having carbon dioxide selectivity and permeation rate and superior mechanical strength can be obtained. In this specification, the "content of polyorganosiloxane block (A-2) in polycarbonate-polyorganosiloxane copolymer (A)" refers to the percentage of the mass of the general formula (II) relative to the total mass of the polycarbonate block (A-1), the general formula (II), and, if necessary, the terminal structure derived from the terminal terminator contained in the polycarbonate-polyorganosiloxane copolymer (A), as described below. The content of polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is calculated by nuclear magnetic resonance (NMR) measurement. Specifically, 1H NMR measurement is carried out, and the value is calculated from the integral values ​​of the peak derived from formula (I), the peak derived from formula (II), and the peak derived from the terminal group.

[0031] A preferred embodiment of the polyorganosiloxane block (A-2) containing the repeating unit represented by the above general formula (II) is a block unit represented by any one of the following general formulas (II-I) to (II-III).

[0032]

[0033] [In the formula, R 3 ~R 6 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, and a plurality of R 3 ~R 6 may be the same or different. Y is -R 7 O-, -R 7 COO-, -R 7 NH-, -R 7 NR 8 -, -COO-, -S-, -R 7 COO-R 9 -O- or -R 7 O-R 10 The R represents —O—, and the plurality of Ys may be the same or different. 7 represents a single bond, a linear, branched or cyclic alkylene group, an aryl-substituted alkylene group, a substituted or unsubstituted arylene group, or a diarylene group. 8 represents an alkyl group, an alkenyl group, an aryl group, or an aralkyl group. 9 represents a diarylene group. 10 represents a linear, branched, or cyclic alkylene group, or a diarylene group. β represents a divalent group derived from a diisocyanate compound, or a divalent group derived from a dicarboxylic acid or a dicarboxylic acid halide. n is as defined above. p is an integer of 1 or more and n-2 or less.]

[0034] R 3 ~R 6The halogen atoms independently represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 3 ~R 6 Examples of alkyl groups that R each independently represent include methyl, ethyl, n-propyl, isopropyl, various butyl groups, various pentyl groups, and various hexyl groups. 3 ~R 6 The alkoxy groups each independently represent include those in which the alkyl group moiety is the above-mentioned alkyl group. 3 ~R 6 Examples of the aryl group that each R represents independently include a phenyl group and a naphthyl group. 3 ~R 6 is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. 3 ~R 6 are preferably all methyl groups.

[0035] Y indicates -R 7 O-, -R 7 COO-, -R 7 NH-, -R 7 NR 8 -, -R 7 COO-R 9 -O- or -R 7 O-R 10 In —O—, R 7 is bonded to the Si atom. In -COO- represented by Y, the C atom is bonded to the Si atom. In -R represented by Y, 7 O-, -R 7 COO-, -R 7 NH-, -R 7 NR 8 -, -R 7 COO-R 9 -O- or -R 7 O-R 10 R in -O- 7 The linear or branched alkylene group represented by R is an alkylene group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms. 7The cyclic alkylene group represented by the formula (I) includes a cycloalkylene group having 5 to 15 carbon atoms, preferably 5 to 10 carbon atoms.

[0036] R 7 The aryl-substituted alkylene group represented by may have a substituent such as an alkoxy group or an alkyl group on the aromatic ring, and its specific structure can be, for example, the structure of the following general formula (i) or (ii). 7 represents an aryl-substituted alkylene group, the alkylene group is bonded to the Si atom. 7 O-, -R 7 COO-, -R 7 NH-, -R 7 NR 8 -, -R 7 COO-R 9 -O- or -R 7 O-R 10 In —O—, the arylene group is R 7 is bonded to an oxygen atom, carbon atom, or nitrogen atom adjacent to the

[0037]

[0038] [In the formula, c represents a positive integer, and is usually an integer of 1 to 6.]

[0039] R 7 , R 9 and R 10 The diarylylene group represented by the formula (I) is a group in which two arylene groups are linked directly or via a divalent organic group, and specifically, -Ar 1 -W-Ar 2 -, where Ar 1 and Ar 2 represents an arylene group, and W represents a single bond or a divalent organic group. The divalent organic group represented by W is, for example, an isopropylidene group, a methylene group, a dimethylene group, or a trimethylene group. R 7 , Ar 1 and Ar 2Examples of the arylene group represented by the formula (I) include arylene groups having 6 to 14 ring carbon atoms, such as a phenylene group, a naphthylene group, a biphenylene group, and an anthrylene group. These arylene groups may have any substituent, such as an alkoxy group or an alkyl group.

[0040] R 8 The alkyl group represented by R is a straight or branched chain alkyl group having 1 to 8 carbon atoms, preferably 1 to 5 carbon atoms. 8 The alkenyl group represented by R is a straight-chain or branched-chain alkenyl group having 2 to 8 carbon atoms, preferably 2 to 5 carbon atoms. 8 Examples of the aryl group represented by R include a phenyl group and a naphthyl group. 8 Examples of the aralkyl group represented by R include a phenylmethyl group and a phenylethyl group. 10 The linear, branched or cyclic alkylene group represented by R 7 is the same as:

[0041] Y is preferably —R 7 O- and R 7 is an aryl-substituted alkylene group. 7 is more preferably a residue of a phenolic compound having an alkyl group, and even more preferably an organic residue derived from allylphenol or an organic residue derived from eugenol. Note that with respect to p in formula (II-II), it is preferable that p=n-p-2.

[0042] β represents a divalent group derived from a diisocyanate compound or a divalent group derived from a dicarboxylic acid or a dicarboxylic acid halide, and examples thereof include divalent groups represented by the following general formulas (iii) to (vii).

[0043]

[0044] For example, examples of the block unit represented by the following general formula (II-I) include block units represented by the following general formulae (II-I-1) to (II-I-11).

[0045]

[0046] In the above general formulae (II-I-1) to (II-I-11), R3 ~R 6 , n-1 and R 8 is the same as above, and the preferred ones are also the same. c represents a positive integer, usually an integer of 1 to 6. Among these, from the viewpoint of ease of polymerization of polyorganosiloxane, the block unit represented by the above general formula (II-I-1) is preferred. Furthermore, from the viewpoint of ease of availability, the block unit represented by the above general formula (II-I-2) and the block unit represented by the above general formula (II-I-3) are preferred.

[0047] Another preferred embodiment of the polyorganosiloxane block (A-2) is a block unit represented by the following general formula (II-IV).

[0048]

[0049] [wherein R 3 and R 4　 is the same as above. r×m is equal to n above.] The average chain length of the polyorganosiloxane block represented by general formula (II-IV) is (r×m), and the range of (r×m) is the same as n above.

[0050] Another preferred embodiment of the polyorganosiloxane block (A-2) is a block unit represented by the following general formula (IV).

[0051]

[0052] [In the formula, R ２１ ~R ２４ are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. ２５ is an alkyl group having 1 to 6 carbon atoms, a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms. ２ is a divalent aliphatic group having 1 to 10 carbon atoms, and m is the average chain length and is an integer of 10 or more.

[0053] R ２１ ~R ２４The halogen atoms independently represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. ２１ ~R ２４ Examples of alkyl groups that R each independently represent include methyl, ethyl, n-propyl, isopropyl, various butyl groups, various pentyl groups, and various hexyl groups. ２１ ~R ２４ The alkoxy groups each independently represent include those in which the alkyl group moiety is the above-mentioned alkyl group. ２１ ~R ２４ Examples of the aryl group that each independently represents include a phenyl group and a naphthyl group.

[0054] R ２５ Examples of the alkyl group having 1 to 6 carbon atoms represented by R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, various butyl groups, various pentyl groups, and various hexyl groups. ２５ Examples of the halogen atom represented by R include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. ２５ The alkoxy group having 1 to 6 carbon atoms represented by R is a group in which the alkyl group moiety is the above-mentioned alkyl group. ２５ Examples of the aryl group having 6 to 14 carbon atoms include a phenyl group, a toluyl group, a dimethylphenyl group, and a naphthyl group.

[0055] Q 2 The divalent aliphatic group having 1 to 10 carbon atoms represented by is preferably a linear or branched divalent saturated aliphatic group having 1 to 10 carbon atoms. The number of carbon atoms in the saturated aliphatic group is preferably 1 to 8, more preferably 2 to 6, even more preferably 3 to 6, and still more preferably 4 to 6. m is the average chain length and is an integer of 10 or more. It is preferably 30 to 70, more preferably 30 to 60, even more preferably 30 to 50, and even more preferably 35 to 45.

[0056] A specific embodiment of the repeating unit (A-3) is a structure represented by the following formula (IV-I).

[0057]

[0058] [In the formula, m is as defined above.]

[0059] In a preferred embodiment of the polycarbonate-polyorganosiloxane copolymer (A), the main chain of the polycarbonate-polyorganosiloxane copolymer (A) consists solely of the polycarbonate block (A-1), the polyorganosiloxane block (A-2), and, if necessary, a terminal structure derived from a terminal terminator described below.

[0060] (Physical Properties of Polycarbonate-Polyorganosiloxane Copolymer (A)) The viscosity average molecular weight Mv of the polycarbonate-polyorganosiloxane copolymer (A) is preferably 12,000 to 30,000, more preferably 13,500 to 25,000, even more preferably 15,000 to 23,000, and even more preferably 16,000 to 21,000. If the viscosity average molecular weight Mv is within the above range, a gas separation membrane having better carbon dioxide selectivity and permeation rate, as well as mechanical strength, can be obtained. The viscosity average molecular weight (Mv) of the polycarbonate-polyorganosiloxane copolymer (A) can be appropriately adjusted by using a molecular weight modifier (terminal capping agent) or the like to achieve the desired molecular weight.

[0061] The viscosity average molecular weight (Mv) is a value calculated from the intrinsic viscosity [η] of a methylene chloride solution at 20° C. using the Schnell formula below.

[0062]

[0063] (Method for producing polycarbonate-polyorganosiloxane copolymer (A)) The polycarbonate-polyorganosiloxane copolymer (A) can be produced by known production methods such as interfacial polymerization (phosgene method), pyridine method, transesterification method, etc. In particular, when the interfacial polymerization method is used, the separation process of the organic phase containing the polycarbonate-polyorganosiloxane copolymer and the aqueous phase containing unreacted materials, catalyst residues, etc. is easy, and the organic phase containing the polycarbonate-polyorganosiloxane copolymer and the aqueous phase are easily separated in each washing process such as alkali washing, acid washing, and pure water washing. Therefore, the polycarbonate-polyorganosiloxane copolymer can be obtained efficiently. As a method for producing a polycarbonate-polyorganosiloxane copolymer, for example, the method described in JP 2014-80462 A can be referenced.

[0064] In the interfacial polymerization method (phosgene method), for example, a polycarbonate oligomer is prepared in advance by polymerizing a dihydric phenol compound with a carbonate precursor such as phosgene, and then the polycarbonate oligomer, polyorganosiloxane, and optionally a dihydric phenol compound are polymerized to produce the PC-POS copolymer (S-1). Specifically, the polycarbonate oligomer and polyorganosiloxane prepared in advance, which will be described later, are dissolved in a water-insoluble organic solvent (e.g., methylene chloride), and an alkaline compound aqueous solution (e.g., sodium hydroxide aqueous solution) of a dihydric phenol compound (e.g., bisphenol A) is added. The copolymer can be produced by an interfacial polycondensation reaction using a tertiary amine (e.g., triethylamine) or a quaternary ammonium salt (e.g., trimethylbenzylammonium chloride) as a polymerization catalyst in the presence of a terminal terminator (a monohydric phenol such as p-tert-butylphenol). The polycarbonate-polyorganosiloxane copolymer (A) can also be produced by copolymerizing a polyorganosiloxane, a dihydric phenol compound, and phosgene, a carbonate ester, or a chloroformate.

[0065] As the polyorganosiloxane used as the raw material, those represented by the following general formula (1), (2) and / or (3) can be used.

[0066]

[0067] [In the formula, R 3 ~R 6 , Y, β, n and p are as defined above.] R 3 ~R 6 Specific examples and preferred values ​​of Y, β, n, and p are as described above. Z represents a hydrogen or halogen atom, and multiple Zs may be the same or different. For example, polyorganosiloxanes represented by general formula (1) include compounds of the following general formulas (1-1) to (1-11).

[0068]

[0069] In the above general formulas (1-1) to (1-11), R 3 ~R 6 , n-1 and R 8 is the same as above, and the preferred ones are also the same. c represents a positive integer, usually an integer of 1 to 6. Among these, from the viewpoint of ease of polymerization of polyorganosiloxane, phenol-modified polyorganosiloxane represented by the above general formula (1-1) is preferred. Furthermore, from the viewpoint of ease of availability, α,ω-bis[3-(o-hydroxyphenyl)propyl]polydimethylsiloxane, which is one of the compounds represented by the above general formula (1-2), and α,ω-bis[3-(4-hydroxy-3-methoxyphenyl)propyl]polydimethylsiloxane, which is one of the compounds represented by the above general formula (1-3), are preferred.

[0070] Alternatively, a polyorganosiloxane represented by the following general formula (4) may be used as the polyorganosiloxane raw material.

[0071]

[0072] [In the formula, R 3 , R 4 , r and m are the same as above.]

[0073] Alternatively, polyorganosiloxanes represented by the following general formula (5) or (6) may be used as the polyorganosiloxane raw material.

[0074]

[0075] [In the formula, R ２１ ~R ２５ , Q ２ and m are the same as above.]

[0076]

[0077] [In the formula, m is the same as defined above.]

[0078] The method for producing the polyorganosiloxane is not particularly limited. For example, according to the method described in JP-A-11-217390, cyclotrisiloxane and disiloxane are reacted in the presence of an acidic catalyst to synthesize an α,ω-dihydrogenorganopentasiloxane, and then a phenolic compound (e.g., 2-allylphenol, 4-allylphenol, eugenol, 2-propenylphenol, etc.) is added to the α,ω-dihydrogenorganopentasiloxane in the presence of a hydrosilylation catalyst to produce a crude polyorganosiloxane. According to the method described in Japanese Patent No. 2662310, octamethylcyclotetrasiloxane and tetramethyldisiloxane are reacted in the presence of sulfuric acid (an acidic catalyst), and the resulting α,ω-dihydrogenorganopolysiloxane is subjected to an addition reaction with a phenolic compound or the like in the presence of a hydrosilylation catalyst, as described above, to obtain a crude polyorganosiloxane. The α,ω-dihydrogenorganopolysiloxane can be used by adjusting the chain length n appropriately depending on the polymerization conditions, or a commercially available α,ω-dihydrogenorganopolysiloxane can be used. Specifically, the α,ω-dihydrogenorganopolysiloxane described in Japanese Patent Laid-Open No. 2016-098292 can be used.

[0079] Polycarbonate oligomers can be produced by reacting a dihydric phenol with a carbonate precursor such as phosgene or triphosgene in an organic solvent such as methylene chloride, chlorobenzene, or chloroform. When producing a polycarbonate oligomer using a transesterification method, it can also be produced by reacting a dihydric phenol with a carbonate precursor such as diphenyl carbonate. As the dihydric phenol, it is preferable to use a dihydric phenol represented by the following general formula (viii):

[0080]

[0081] In the formula, R 1 , R 2 , a, b and X are as defined above.

[0082] Examples of dihydric phenols represented by the general formula (viii) include bis(hydroxyphenyl)alkane diphenols such as 2,2-bis(4-hydroxyphenyl)propane (bisphenol A), bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, and 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane; 4,4'-dihydroxydiphenyl; bis(4-hydroxyphenyl)cycloalkane; bis(4-hydroxyphenyl)oxide; bis(4-hydroxyphenyl)sulfide; bis(4-hydroxyphenyl)sulfone; bis(4-hydroxyphenyl)sulfoxide; and bis(4-hydroxyphenyl)ketone. These dihydric phenols may be used alone or in combination of two or more. Among these, bis(hydroxyphenyl)alkane dihydric phenols are preferred, and bisphenol A is more preferred. When bisphenol A is used as the dihydric phenol compound, the resulting PC-POS copolymer has the general formula (i) in which X is an isopropylidene group and a=b=0.

[0083] Examples of dihydric phenol compounds other than bisphenol A include bis(hydroxyaryl)alkanes, bis(hydroxyaryl)cycloalkanes, dihydroxyaryl ethers, dihydroxydiaryl sulfides, dihydroxydiaryl sulfoxides, dihydroxydiaryl sulfones, dihydroxydiphenyls, dihydroxydiarylfluorenes, dihydroxydiaryladamantanes, etc. These dihydric phenol compounds may be used alone or in combination of two or more.

[0084] Examples of bis(hydroxyaryl)alkanes include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, bis(4-hydroxyphenyl)diphenylmethane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, bis(4-hydroxyphenyl)naphthylmethane, 1,1-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3-chlorophenyl)propane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, and 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane.

[0085] Examples of bis(hydroxyaryl)cycloalkanes include 1,1-bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,5,5-trimethylcyclohexane, 2,2-bis(4-hydroxyphenyl)norbornane, 1,1-bis(4-hydroxyphenyl)cyclododecane, etc. Examples of dihydroxyaryl ethers include 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy-3,3'-dimethylphenyl ether, etc.

[0086] Examples of dihydroxydiaryl sulfides include 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, etc. Examples of dihydroxydiaryl sulfoxides include 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, etc. Examples of dihydroxydiaryl sulfones include 4,4'-dihydroxydiphenyl sulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone, etc.

[0087] Examples of dihydroxydiphenyls include 4,4'-dihydroxydiphenyl, etc. Examples of dihydroxydiaryladamantanes include 1,3-bis(4-hydroxyphenyl)adamantane, 2,2-bis(4-hydroxyphenyl)adamantane, 1,3-bis(4-hydroxyphenyl)-5,7-dimethyladamantane, etc.

[0088] Other dihydric phenol compounds include, for example, 4,4'-[1,3-phenylenebis(1-methylethylidene)]bisphenol, 10,10-bis(4-hydroxyphenyl)-9-anthrone, and 1,5-bis(4-hydroxyphenylthio)-2,3-dioxapentane.

[0089] A terminal terminator (molecular weight regulator) can be used to adjust the molecular weight of the resulting PC-POS copolymer. Examples of terminal terminators include monohydric phenols such as phenol, p-cresol, p-tert-butylphenol, p-tert-octylphenol, p-cumylphenol, p-nonylphenol, m-pentadecylphenol, and p-tert-amylphenol. These monohydric phenols may be used alone or in combination of two or more.

[0090] After the interfacial polycondensation reaction, the mixture is appropriately allowed to stand to separate into an aqueous phase and an organic solvent phase [separation step], the organic solvent phase is washed (preferably with a basic aqueous solution, an acidic aqueous solution, and water in that order) [washing step], and the resulting organic phase is concentrated [concentration step]. Then, the resulting organic phase is dried [drying step] to obtain a polycarbonate-polyorganosiloxane copolymer (A).

[0091] <Gas Separation Membrane> The gas separation membrane of the present invention contains a polycarbonate-polyorganosiloxane copolymer (A). The content of the polycarbonate-polyorganosiloxane copolymer (A) in the gas separation membrane is preferably 80% by mass or more, more preferably 95% by mass or more, even more preferably 99% by mass, and even more preferably 100% by mass. When the content of the polycarbonate-polyorganosiloxane copolymer (A) in the gas separation membrane is within the above range, a gas separation membrane having better carbon dioxide selectivity and permeation amount, as well as better mechanical strength, can be obtained.

[0092] The thickness of the gas separation membrane of the present invention is preferably from 1 μm to 1000 μm, more preferably from 5 μm to 500 μm, and even more preferably from 10 μm to 250 μm. If the thickness of the gas separation membrane is within this range, the gas separation membrane will have better carbon dioxide permeation rate and tear strength.

[0093] The gas separation membrane may contain other additives, such as hydrolysis stabilizers, antioxidants, ultraviolet absorbers, flame retardants, flame retardant assistants, reinforcing materials, fillers, impact-improving elastomers, crosslinking agents, pigments, and dyes, as long as the additives do not impair the effects of the present invention.

[0094] (Antioxidant) A specific example of the other additives is an antioxidant. By blending an antioxidant into the polycarbonate resin composition, it is possible to suppress oxidative degradation of the polycarbonate resin composition when it is melted, and to suppress coloration and the like due to oxidative degradation. As the antioxidant, a phosphorus-based antioxidant and / or a phenol-based antioxidant is preferably used.

[0095] Examples of phenolic antioxidants include hindered phenols such as n-octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, 2,6-di-tert-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), and pentaerythrityl tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]. Among these antioxidants, those having a pentaerythritol diphosphite structure, such as bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and triphenylphosphine are preferred.

[0096] Examples of commercially available phenolic antioxidants include Irganox 1010 (trade name, manufactured by BASF Japan Ltd.), Irganox 1076 (trademark, manufactured by BASF Japan Ltd.), Irganox 1330 (trade name, manufactured by BASF Japan Ltd.), Irganox 3114 (trade name, manufactured by BASF Japan Ltd.), BHT (trade name, manufactured by Takeda Pharmaceutical Co., Ltd.), CYANOX 1790 (trade name, manufactured by SOLVAY), and Sumilizer GA-80 (trade name, manufactured by Sumitomo Chemical Co., Ltd.).

[0097] Examples of phosphorus-based antioxidants include triphenyl phosphite, diphenyl nonyl phosphite, diphenyl(2-ethylhexyl) phosphite, tris(2,4-di-tert-butylphenyl) phosphite, tris(nonylphenyl) phosphite, diphenyl isooctyl phosphite, 2,2'-methylenebis(4,6-di-tert-butylphenyl)octyl phosphite, diphenyl isodecyl phosphite, diphenyl mono(tridecyl) phosphite, phenyl diisodecyl phosphite, phenyl di(tridecyl) phosphite, tris(2-ethylhexyl) phosphite, tris(isodecyl) phosphite, tris(tridecyl) phosphite, dibutyl hydrogen phosphite, trilauryl trithiophosphite, tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite, 4,4'-isopropylidenediphenol dodecyl phosphite, sphite, 4,4'-isopropylidenediphenol tridecyl phosphite, 4,4'-isopropylidenediphenol tetradecyl phosphite, 4,4'-isopropylidenediphenol pentadecyl phosphite, 4,4'-butylidenebis(3-methyl-6-tert-butylphenyl)ditridecyl phosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl -4-methylphenyl)pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, distearyl-pentaerythritol diphosphite, phenyl bisphenol A pentaerythritol diphosphite, tetraphenyl dipropylene glycol diphosphite, 1,1,3-tris(2-methyl-4-di-tridecylphosphite-5-tert-butylphenyl)butane, 3,4,5,6-dibenzo-1,Examples of such phosphine include 2-oxaphosphine, triphenylphosphine, diphenylbutylphosphine, diphenyloctadecylphosphine, tris(p-tolyl)phosphine, tris(p-nonylphenyl)phosphine, tris(naphthyl)phosphine, diphenyl(hydroxymethyl)phosphine, diphenyl(acetoxymethyl)phosphine, diphenyl(β-ethylcarboxyethyl)phosphine, tris(p-chlorophenyl)phosphine, tris(p-fluorophenyl)phosphine, benzyldiphenylphosphine, diphenyl(β-cyanoethyl)phosphine, diphenyl(p-hydroxyphenyl)phosphine, diphenyl(1,4-dihydroxyphenyl)-2-phosphine, and phenylnaphthylbenzylphosphine.

[0098] Examples of commercially available phosphorus-based antioxidants include Irgafos 168 (trade name, manufactured by BASF Japan Ltd.), Irgafos 12 (trade name, manufactured by BASF Japan Ltd.), Irgafos 38 (trade name, manufactured by BASF Japan Ltd.), Adeka STAB 2112 (trade name, manufactured by ADEKA Corporation), Adeka STAB C (trade name, manufactured by ADEKA Corporation), Adeka STAB 329K (trade name, manufactured by ADEKA Corporation), Adeka STAB PEP36 (trade name, manufactured by ADEKA Corporation), JC-263 (trade name, manufactured by Johoku Chemical Industry Co., Ltd.), Sandstab P-EPQ (trade name, manufactured by Clariant), and Doverphos S-9228PC (trade name, manufactured by Dover Chemical Co., Ltd.).

[0099] The above antioxidants can be used alone or in combination of two or more. The content of the antioxidant in the gas separation membrane of the present invention is preferably 0.001 to 0.5 parts by mass, more preferably 0.01 to 0.3 parts by mass, and even more preferably 0.05 to 0.3 parts by mass, per 100 parts by mass of the gas separation membrane. If the content of the antioxidant per 100 parts by mass of the gas separation membrane is within the above range, a sufficient antioxidant effect can be obtained.

[0100] The gas separation membrane of the present invention may be composed of either a membrane containing the polycarbonate-polyorganosiloxane copolymer (A) alone or a laminate in which a membrane containing the polycarbonate-polyorganosiloxane copolymer (A) is disposed on a support. Examples of the support include woven fabric and nonwoven fabric. Examples of woven fabric and nonwoven fabric include those using fibers made of polyester, polypropylene, polyacrylonitrile, polyethylene, polyamide, etc.

[0101] The gas separation membrane of the present invention is a gas separation membrane for separating carbon dioxide from a mixed gas containing carbon dioxide. Examples of gases other than carbon dioxide contained in the mixed gas include carbon monoxide, nitrogen, oxygen, hydrogen, hydrogen sulfide, nitrogen oxides, sulfur oxides, silane compounds, fluorine, chlorine, rare gases, and hydrocarbon compounds. Examples of nitrogen oxides include nitric oxide and nitrogen dioxide. Examples of sulfur oxides include sulfur monoxide, sulfur dioxide, and sulfur trioxide. Examples of silane compounds include monosilane and disilane. Examples of rare gases include helium and argon. Examples of hydrocarbon compounds include methane, ethane, ethylene, propane, propylene, butane, and butylene. Examples of preferred mixed gases include exhaust gases from factories, power plants, automobiles, and the like.

[0102] (Production Method) The gas separation membrane of the present invention can be produced by a known method. For example, the gas separation membrane can be obtained by using a melt-kneaded product of the polycarbonate-polyorganosiloxane copolymer (A) or the resulting pellets as a raw material, and by various methods for producing a molded article, such as injection molding, injection compression molding, extrusion molding, blow molding, press molding, vacuum molding, foam molding, cast molding, spin coating molding, and blade molding.

[0103] (Physical Properties of Gas Separation Membrane) The gas separation membrane of the present invention has excellent carbon dioxide selectivity. Carbon dioxide selectivity can be determined, for example, by the total gas permeability (GTR) of oxygen and nitrogen. Ｏ２+Ｎ２ Gas permeability GTR of carbon dioxide ＣＯ２ The gas permeability ratio GTR is defined as the ratio of ＣＯ２ / GTR Ｏ２+Ｎ２The gas separation membrane of the present invention can be evaluated by the above gas permeability ratio GTR ＣＯ２ / GTR Ｏ２+Ｎ２ is preferably 10.0 or more, more preferably 10.2 or more, and even more preferably 10.4 or more.

[0104] The gas separation membrane of the present invention also has excellent carbon dioxide permeability. The carbon dioxide permeability can be evaluated, for example, by the carbon dioxide permeability coefficient. The gas separation membrane of the present invention preferably has a product of the carbon dioxide permeability coefficient (unit: Barrer) and the membrane thickness (unit: μm) of 5.0×10 ３ or more, more preferably 1.0 × 10 ４ More preferably, 1.0×10 ５ The gas permeability ratio and the carbon dioxide permeability coefficient are measured in accordance with the differential pressure method of JIS K 7126-1:2006. Specifically, under the test temperature condition of 23°C as described in the examples, one side separated by a gas separation membrane is kept in vacuum (low pressure side), and a mixed gas (N ２ :O ２ :CO ２ The pressure difference was set to 1 atmosphere, and the N permeated through the gas separation membrane to the low pressure side was ２ and O ２ Total and CO ２ The amount of gas is measured by gas chromatography.

[0105] The gas separation membrane of the present invention also has excellent mechanical strength. The mechanical strength can be evaluated, for example, by the notched crescent tear strength in accordance with JIS K6252-1:2015. The gas separation membrane of the present invention has a notched crescent tear strength in the MD direction measured in accordance with JIS K6252-1:2015 of preferably 10 kN / m or more, more preferably 30 kN / m or more, and even more preferably 100 kN / m or more.

[0106] (Use) The gas separation membrane of the present invention can be used, for example, in an exhaust gas purification device comprising the gas separation membrane of the present invention.

[0107] <Use for separating carbon dioxide from a mixed gas containing carbon dioxide> The present invention also provides use of a polymer membrane containing the polycarbonate-polyorganosiloxane copolymer (A) for separating carbon dioxide from a mixed gas containing carbon dioxide.

[0108] <Method for Separating Carbon Dioxide from a Gas Mixture Containing Carbon Dioxide> The present invention also provides a method for separating carbon dioxide from a gas mixture containing carbon dioxide. Specifically, the method for separating carbon dioxide of the present invention comprises a step of contacting the gas mixture containing carbon dioxide with the gas separation membrane described above.

[0109] Although the mode of contacting the mixed gas with the gas separation membrane is not particularly limited, a preferred mode is to supply the mixed gas to one side of the gas separation membrane, allow the mixed gas to permeate the gas separation membrane, and recover a gas with an increased carbon dioxide concentration from the other side of the gas separation membrane. In such a mode, the pressure difference between the supply side and the recovery side of the mixed gas is preferably 0.01 atmospheres or more and 1000 atmospheres or less, more preferably 0.01 atmospheres or more and 1000 atmospheres or less. Note that 1 atmosphere = 0.101 MPa.

[0110] The present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples. The characteristic values ​​and evaluation results in each example were determined according to the following procedures.

[0111] (1) Average chain length and content of polyorganosiloxane block (A-2) １ The average chain length and content of the polyorganosiloxane block (A-2) were calculated from the integral ratio of the methyl groups of the polydimethylsiloxane constituting the polyorganosiloxane block (A-2) by H-NMR measurement. In this specification, polydimethylsiloxane may be abbreviated as PDMS. <Method for Quantifying the Average Chain Length of the Polyorganosiloxane Block (A-2)> ( １ H-NMR measurement conditions) NMR device: ECA-500 manufactured by JEOL RESONANCE Co., Ltd. Probe: 50TH5AT / FG2 Measurement nucleus: １H Observation range: -5 to 15 ppm Observation center: 5 ppm Pulse repetition time: 9 seconds Pulse width: 45° NMR sample tube: 5φ Sample amount: 30 to 40 mg Solvent: deuterated chloroform Measurement temperature: room temperature Number of accumulations: 256 (Method for calculating the average chain length of polyorganosiloxane block (A-2)) In the case of allylphenol-terminated polydimethylsiloxane A: integral value of the methyl group of the dimethylsiloxane portion observed in the vicinity of δ-0.02 to 0.5 B: integral value of the methylene group of allylphenol observed in the vicinity of δ 2.50 to 2.75 Chain length of polydimethylsiloxane = (A / 6) / (B / 4) In the case of eugenol-terminated polydimethylsiloxane A: integral value of the methyl group of the dimethylsiloxane portion observed in the vicinity of δ-0.02 to 0.5 B: integral value of methylene groups of eugenol observed in the vicinity of δ 2.40 to 2.70 Chain length of polydimethylsiloxane = (A / 6) / (B / 4)

[0112] <Method for quantifying the content of polyorganosiloxane block (A-2)> Example: Method for quantifying the amount of polydimethylsiloxane copolymerized in p-tert-butylphenyl (PTBP)-terminated polycarbonate copolymerized with allylphenol-terminated polydimethylsiloxane ( １ H-NMR measurement conditions) NMR device: ECA-500 manufactured by JEOL RESONANCE Co., Ltd. Probe: 50TH5AT / FG2 Measurement nucleus: １H Observation range: -5 to 15 ppm Observation center: 5 ppm Pulse repetition time: 9 seconds Pulse width: 45° Number of accumulations: 256 times NMR sample tube: 5φ Sample amount: 30 to 40 mg Solvent: deuterated chloroform Measurement temperature: room temperature (Method of calculating the content of polyorganosiloxane block (A-2)) A: integral value of the methyl group of bisphenol A (BPA part) observed around δ 1.5 to 1.9 B: integral value of the methyl group of the dimethylsiloxane part observed around δ -0.02 to 0.3 C: integral value of the butyl group of the p-tert-butylphenyl (PTBP) part observed around δ 1.2 to 1.4 a = A / 6 b = B / 6 c = C / 9 T = a + b + c f = a / T × 100 g = b / T × 100 h = c / T × 100 TW=f×254+g×74.1+h×149 PDMS (wt%)=g×74.1 / TW×100

[0113] (2) Viscosity Average Molecular Weight The viscosity average molecular weight (Mv) was calculated by measuring the viscosity of a methylene chloride solution at 20°C using an Ubbelohde viscometer, determining the intrinsic viscosity [η] from the viscosity, and then using the following formula (Schnell's formula):

[0114]

[0115] Synthesis Example 1: Production of Polycarbonate Oligomer A 5.6 mass % aqueous solution of sodium hydroxide was added with sodium dithionite (Na ２ S ２ O ４) was added to the solution to a concentration of 2000 ppm relative to the bisphenol A (BPA) to be dissolved later. BPA was dissolved in the solution to a BPA concentration of 13.5% by mass, to prepare an aqueous sodium hydroxide solution of BPA. This aqueous sodium hydroxide solution of BPA was continuously passed through a tubular reactor with an inner diameter of 6 mm and a tube length of 30 m at flow rates of 40 L / hr, methylene chloride at 15 L / hr, and phosgene at 4.0 kg / hr. The tubular reactor had a jacket, and cooling water was passed through the jacket to maintain the temperature of the reaction solution below 40°C. The reaction solution leaving the tubular reactor was continuously introduced into a 40 L baffled tank reactor equipped with swept-back blades, and a reaction was carried out by adding an aqueous sodium hydroxide solution of BPA at a flow rate of 2.8 L / hr, a 25% by mass aqueous sodium hydroxide solution at a flow rate of 0.07 L / hr, water at a flow rate of 17 L / hr, and a 1% by mass aqueous triethylamine solution at a flow rate of 0.64 L / hr. The reaction solution overflowing from the tank reactor was continuously withdrawn and allowed to stand, allowing the aqueous phase to be separated and removed, and the methylene chloride phase to be collected. The polycarbonate oligomer thus obtained had a concentration of 227 g / L and a chloroformate group concentration of 0.80 mol / L.

[0116] <Production Example 1: Production of polycarbonate-polyorganosiloxane copolymer> A 50 L separable flask equipped with a baffle plate and a mechanical stirrer with a stirring blade was charged with 15.8 L of the polycarbonate oligomer solution (PCO) produced in Synthesis Example 1 above, 20 L of methylene chloride, 1600 g of allylphenol-terminated polydimethylsiloxane having an average chain length n = 37, and 0.104 mL (72.2 mmol) of triethylamine (TEA), and a previously prepared aqueous sodium hydroxide solution A (NaOHaq) (101 g (2.53 mol) of sodium hydroxide dissolved in 1.16 L of ion-exchanged water) was added thereto under stirring, and the polycarbonate oligomer and allylphenol-terminated PDMS were reacted for 20 minutes. The obtained polymerization solution was mixed with a solution of p-tert-butylphenol (PTBP: manufactured by DIC Corporation) in methylene chloride [PTBP: 109 g (0.727 mol) dissolved in 434 mL of methylene chloride], an aqueous solution of sodium hydroxide B of BPA [bisphenol A: 1040 g (4.56 mol), NaOH: 658 g (16.5 mol), and sodium dithionite (Na ２ S ２ O ４ 0.031 g (11.9 mmol) of PEG-100 HCl dissolved in 9.62 L of ion-exchanged water was added, and the polymerization reaction was carried out for 20 minutes. After polymerization was completed, the reaction solution was transferred to a separatory funnel and allowed to stand to separate into an organic phase and an aqueous phase. The organic phase was then transferred to another separatory funnel. The mixture was washed sequentially with 4.45 L of a 0.03 mol / L aqueous NaOH solution and 4.25 L of a 0.2 mol / L hydrochloric acid solution, and then repeatedly washed with ion-exchanged water until the electrical conductivity of the aqueous phase after washing reached 10 μS / m or less. The organic phase obtained after washing was transferred to a tray and dried overnight at 48°C in an explosion-proof dryer (under a nitrogen atmosphere) to obtain a sheet-like PC-POS copolymer. This sheet-like PC-POS copolymer was cut into flakes to obtain PC-POS copolymer (A1). The PC-POS copolymer (A1) had a viscosity average molecular weight (Mv) of 18,300, an average chain length of the polyorganosiloxane block (A-2) of 37, and a content of the polyorganosiloxane block (A-2) of 28 mass%.

[0117] <Production Example 2: Production of polycarbonate-polyorganosiloxane copolymer> 14.9 L of polycarbonate oligomer solution (PCO), 18.9 L of methylene chloride, and 3,480 g of allylphenol-terminated polydimethylsiloxane were used. As the sodium hydroxide aqueous solution A, a solution prepared by dissolving 95.3 g (2.38 mol) of NaOH in 1.10 L of ion-exchanged water was used. 102 g (0.680 mol) of PTBP was used. As the sodium hydroxide aqueous solution B, 978 g (4.30 mol) of bisphenol A, 619 g (15.5 mmol) of NaOH, and 102 g (0.680 mol) of PTBP were used. ２ S ２ O ４ A PC-POS copolymer (A2) was obtained in the same manner as in Production Example 1, except that 1.96 g (11.3 mmol) of PEG-100 stearate was dissolved in 9.06 L of ion-exchanged water. The PC-POS copolymer (A2) had a viscosity-average molecular weight (Mv) of 17,900, an average chain length of the polyorganosiloxane blocks (A-2) of 38, and a polyorganosiloxane block (A-2) content of 46 mass%.

[0118] <Production Example 3: Production of polycarbonate-polyorganosiloxane copolymer> 14.7 L of polycarbonate oligomer solution (PCO), 18.7 L of methylene chloride, and 4770 g of allylphenol-terminated polydimethylsiloxane were used. As the sodium hydroxide aqueous solution A, a solution prepared by dissolving 94.1 g (2.35 mol) of NaOH in 1.08 L of ion-exchanged water was used. 95.8 g (0.639 mol) of PTBP was used. As the sodium hydroxide aqueous solution B, 966 g (4.24 mol) of bisphenol A, 612 g (15.5 mmol) of NaOH, and Na ２ S ２ O ４ A PC-POS copolymer (A3) was obtained in the same manner as in Production Example 1, except that 1.93 g (11.1 mmol) of PEG-100 methylcellulose (PEG-100 methylcellulose) was dissolved in 8.95 L of ion-exchanged water. The PC-POS copolymer (A3) had a viscosity-average molecular weight (Mv) of 17,400, an average chain length of the polyorganosiloxane blocks (A-2) of 38, and a polyorganosiloxane block (A-2) content of 55 mass%.

[0119] <Production Example 4: Production of polycarbonate-polyorganosiloxane copolymer> 14.7 L of polycarbonate oligomer solution (PCO), 18.7 L of methylene chloride, and 3,480 g of allylphenol-terminated polydimethylsiloxane were used. As the sodium hydroxide aqueous solution A, a solution prepared by dissolving 95.3 g (2.38 mol) of NaOH in 1.10 L of ion-exchanged water was used. 102 g (0.680 mol) of PTBP was used. As the sodium hydroxide aqueous solution B, 966 g (4.24 mol) of bisphenol A, 612 g (15.5 mmol) of NaOH, and 102 g (0.680 mol) of PTBP were used. ２ S ２ O ４ A PC-POS copolymer (A4) was obtained in the same manner as in Production Example 1, except that 1.93 g (11.3 mmol) of PC-POS copolymer (A-1) was dissolved in 8.95 L of ion-exchanged water. The PC-POS copolymer (A4) had a viscosity-average molecular weight (Mv) of 19,800, an average chain length of the polyorganosiloxane block (A-2) of 40, and a polyorganosiloxane block (A-2) content of 56 mass%.

[0120] <Production Example 5: Production of polycarbonate-polyorganosiloxane copolymer> 129 mL of polycarbonate oligomer solution (PCO), 171 mL of methylene chloride, 85.0 g of allylphenol-terminated polydimethylsiloxane, and 0.083 mL (0.60 mmol) of triethylamine (TEA) were used. As the sodium hydroxide aqueous solution A, a solution of 0.8 g (20 mmol) of NaOH in 10 mL of ion-exchanged water was used. As the methylene chloride solution of PTBP, a solution of 0.98 g (6.5 mmol) of PTBP in 10 mL of methylene chloride was used. As the sodium hydroxide aqueous solution B, a solution of 7.9 g (28 mmol) of bisphenol A, 5.4 g (136 mmol) of NaOH, and 0.083 mL (0.60 mmol) of triethylamine (TEA) were used. ２ S ２ O ４A PC-POS copolymer (A5) was obtained in the same manner as in Production Example 1, except that 0.02 g (0.11 mmol) of PC-POS copolymer (A-1) was dissolved in 80 mL of ion-exchanged water. The PC-POS copolymer (A5) had a viscosity-average molecular weight (Mv) of 17,900, an average chain length of the polyorganosiloxane block (A-2) of 40, and a polyorganosiloxane block (A-2) content of 65 mass%.

[0121] <Production Example 6: Production of polycarbonate-polyorganosiloxane copolymer> 12.4 L of polycarbonate oligomer solution (PCO), 14.7 L of methylene chloride, and 3045 g of allylphenol-terminated polydimethylsiloxane were used. As the sodium hydroxide aqueous solution A, a solution prepared by dissolving 57 g (1.43 mol) of NaOH in 0.653 L of ion-exchanged water was used. 41.7 g (0.278 mol) of PTBP was used. As the sodium hydroxide aqueous solution B, a solution containing 715 g (3.13 mol) of bisphenol A, 715 g (3.13 mol) of NaOH, and Na ２ S ２ O ４ A PC-POS copolymer (A6) was obtained in the same manner as in Production Example 1, except that 369 g (9.2 mmol) of PC-POS copolymer (A-1) was dissolved in 5.4 L of ion-exchanged water. The PC-POS copolymer (A6) had a viscosity-average molecular weight (Mv) of 24,900, an average chain length of the polyorganosiloxane block (A-2) of 37, and a polyorganosiloxane block (A-2) content of 55 mass%.

[0122] Examples 1 to 5 (1) Preparation of Gas Separation Membranes The PC-POS copolymers obtained in Production Examples 1 to 4 shown in Table 1 were melt-kneaded and pelletized, and these were extrusion-molded to obtain films having the thicknesses shown in Table 1.

[0123] (2) Evaluation Test of Carbon Dioxide Separation Performance The evaluation test of the carbon dioxide separation performance of the obtained gas separation membrane was carried out in accordance with the differential pressure method of JIS K 7126-1:2006. Specifically, one side separated by the gas separation membrane was kept in vacuum (low pressure side), and a mixed gas (N ２ :O ２ :CO ２= 8:1:1) was introduced, and nitrogen (N ２ ) and oxygen (O ２ ) and carbon dioxide (CO ２ The gas amount was measured by gas chromatography. The test temperature was 23°C, the pressure difference between both sides of the gas separation membrane was 1 atmosphere, and the gas permeation area was 15.2 × 10 for Examples 1, 2, and 4. －４ m ２ , and Examples 3 and 5 are 0.785 × 10 －４ m ２ It was.

[0124] The following measuring devices were used: Differential pressure gas / vapor permeability measuring device: GTR-30XADJ4, manufactured by GTR Tech Co., Ltd. Gas chromatography detector: G2700T·F, manufactured by GTR Tech Co., Ltd. From the measured amount of permeated gas, the gas permeability (GTR) and gas permeability coefficient (P) were calculated using the following formula. The results are shown in Table 1.

[0125] Gas permeability (GTR) = 273 × (Dv - Db) × k / (22.4 × T × A × t × Δp) GTR: Gas permeability [mol / (m ２ s Pa)] T: Test temperature (K) t: Permeation time (seconds (s)) Db: Blank amount of permeating gas (l) Dv: Measured amount of permeating gas (l) Δp: Partial pressure of high-pressure gas (Pa) A: Permeation area (m ２ ) k: Equipment constant for calculating the total volume of the low-pressure side from the volume of the measuring pipe

[0126] Gas permeability coefficient (P) = GTR × d P: Gas permeability coefficient [mol m / (m ２ s Pa)] GTR: Gas permeability [mol / (m ２ s Pa)] d: Average thickness (m) of the test piece (gas permeable portion was measured at four points using a micrometer and the average was used)

[0127] In the tables, the gas permeability coefficient is shown in Barrer units converted according to the following formula: 1 Barrer = 3.35 x 10 －１６ mol m / (m ２ ・s・Pa)

[0128] (3) Evaluation of Mechanical Strength: Tear Test The tear strength of the resulting gas separation membrane was measured in accordance with JIS K6252-1:2015 using a notched crescent-shaped test piece. Specifically, a crescent-shaped test piece was punched out from the resulting gas separation membrane. A 1.0 mm long notch was made in the center of the depression in the test piece in a direction perpendicular to the surface of the test piece. Using a tensile tester (INSTRON 5567, manufactured by INSTRON), a force was applied at a pulling rate of 500 mm / min until the test piece broke. The tear test was performed in the MD direction of the film, and the tear strength (Ts) was calculated using the following formula. The results are shown in Table 1. Ts = F / d Ts: tear strength (kN / m) F: maximum load (kN) d: thickness of test piece (m)

[0129] Comparative Example 1 An evaluation test for carbon dioxide separation performance and an evaluation test for mechanical strength were carried out in the same manner as in Example 1, except that silicone (C1) (ultra-transparent silicone rubber film, model number 3-9207-06, thickness 0.2 mm, manufactured by AS ONE Corporation) was used as the gas separation membrane. The results are shown in Table 1.

[0130]

[0131] Examples 6 to 8 (1) Preparation of Gas Separation Membranes 2.17 g of the PC-POS polymer flakes obtained in Production Examples 3, 5, and 6 above were weighed out and placed in a 20 ml screw can, and 15 ml of dichloromethane was added and the mixture was dissolved by shaking to prepare a polycarbonate solution (PC solution). The obtained PC solution was poured into a 110 mm diameter Petri dish and left to stand at room temperature for 3 hours to volatilize the dichloromethane, yielding a film with the thickness shown in Table 2.

[0132] (2) Evaluation Test of Carbon Dioxide Separation Performance The evaluation test of the carbon dioxide separation performance of the obtained gas separation membrane was carried out in accordance with the differential pressure method of JIS K 7126-1:2006. Specifically, one side separated by the gas separation membrane was kept in vacuum (low pressure side), and a mixed gas (N ２ :O ２ :CO ２ The N permeated through the gas separation membrane to the low pressure side was ２ and O ２ Total and CO ２The amount of gas was measured by gas chromatography. The test temperature was 23°C, the pressure difference between both sides of the gas separation membrane was 1 atmosphere, and the gas permeation area was 50 × 10 －４ m ２ It was.

[0133] The following measuring equipment was used: High-sensitivity water vapor permeability measuring equipment: GTR-3000XATA, manufactured by GTR Tech Co., Ltd.

[0134] From the measured amount of permeated gas, the gas transmission rate (GTR) and the gas permeability coefficient (P) were calculated in the same manner as in Example 1. The results are shown in Table 2.

[0135]

[0136] Examples 7'-8' Comparing the results of Examples 3 and 6, it can be seen that the results obtained using the evaluation method used in Examples 1-5 are different from those obtained using the evaluation method used in Examples 6-8. ２ and O ２ Therefore, for the PC-POS copolymers obtained in Production Examples 5 and 6, the total gas permeability of N obtained by the evaluation method used in Examples 1 to 5 was ２ and O ２ The total gas permeability (estimated value) was estimated by the following formula (A). Furthermore, based on the estimated value, the gas permeability coefficient (P) was calculated in the same manner as in Example 1. The results are shown in Table 3.

[0137] X=Y×(1.89×10 －１０ ) / (2.22 x 10 －１０ ) (A) X: N according to the carbon dioxide separation performance evaluation test method used in Examples 1 to 5 ２ and O ２ Y: Estimated value of total gas permeability according to the carbon dioxide separation performance evaluation test method used in Examples 6 to 8 ２ and O ２ Total gas permeability

[0138]

Claims

1. A gas separation membrane for separating carbon dioxide from a mixed gas containing carbon dioxide, The gas separation membrane contains a polycarbonate-polyorganosiloxane copolymer (A), The polycarbonate-polyorganosiloxane copolymer (A) comprises a polycarbonate block (A-1) consisting solely of repeating structural units represented by the following general formula (I) and a polyorganosiloxane block (A-2) containing repeating structural units represented by the following general formula (II): A gas separation membrane, wherein the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass or more and 70% by mass or less. 【Chemical 1】 [In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO 2 represents -, -O- or -CO-. 3 and R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. a and b each independently represent an integer of 0 to 4.

2. The gas separation membrane according to claim 1, wherein the average chain length n of the polyorganosiloxane block (A-2) is 20 to 150.

3. 3. The gas separation membrane according to claim 1, wherein a and b in the general formula (I) are 0, and X is an isopropylidene group.

4. R in the general formula (II) 3 and R 4 The gas separation membrane according to claim 1 or 2, wherein is a methyl group.

5. The product of the carbon dioxide permeability coefficient (unit: Barrer) and the membrane thickness (unit: μm) is 5.0 × 10 ３ The gas separation membrane according to claim 1 or 2.

6. 3. The gas separation membrane according to claim 1, wherein the mixed gas containing carbon dioxide is an exhaust gas.

7. A use of a polymer membrane comprising a polycarbonate-polyorganosiloxane copolymer (A) for separating carbon dioxide from a gas mixture containing carbon dioxide, comprising: The polycarbonate-polyorganosiloxane copolymer (A) comprises a polycarbonate block (A-1) consisting solely of repeating structural units represented by the following general formula (I) and a polyorganosiloxane block (A-2) containing repeating structural units represented by the following general formula (II): Use of a polymer membrane, wherein the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass or more and 70% by mass or less. 【Chemistry 2】 [In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO 2 represents -, -O- or -CO-. 3 and R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. a and b each independently represent an integer of 0 to 4.

8. A method for separating carbon dioxide from a gas mixture containing carbon dioxide, comprising a step of contacting the gas mixture containing carbon dioxide with a gas separation membrane, The gas separation membrane contains a polycarbonate-polyorganosiloxane copolymer (A), The polycarbonate-polyorganosiloxane copolymer (A) comprises a polycarbonate block (A-1) consisting solely of repeating structural units represented by the following general formula (I) and a polyorganosiloxane block (A-2) containing repeating structural units represented by the following general formula (II): The method, wherein the content of the polyorganosiloxane block (A-2) in the polycarbonate-polyorganosiloxane copolymer (A) is 20% by mass or more and 70% by mass or less. 【Chemistry 3】 [In the formula, R 1 and R 2 each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. X represents a single bond, an alkylene group having 1 to 8 carbon atoms, an alkylidene group having 2 to 8 carbon atoms, a cycloalkylene group having 5 to 15 carbon atoms, a cycloalkylidene group having 5 to 15 carbon atoms, an arylalkylene group having 7 to 15 carbon atoms, an arylalkylidene group having 7 to 15 carbon atoms, -S-, -SO-, -SO 2 represents -, -O- or -CO-. 3 and R 4 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. a and b each independently represent an integer of 0 to 4.

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