JP5805982B2 - Polyarylate resin film and gas separation membrane - Google Patents

Description

  The present invention relates to a polyarylate resin film having excellent carbon dioxide selective separation and heat resistance.

  In recent years, global warming has become a problem, and greenhouse gases are one of the causes. Of the greenhouse gases, carbon dioxide, which is the most released into the atmosphere, is strongly required to reduce its emissions. In order to reduce the emission amount, it is conceivable to reduce the entire emission amount or to selectively collect carbon dioxide gas from the emission gas, but the latter is preferable in order to carry out without suppressing the industrial activity. For this reason, gas separation membranes for separating carbon dioxide from other gases, particularly nitrogen gas, which is contained most in the air, from exhaust gas have been actively developed. As the gas separation membrane, inorganic materials such as ceramic, carbon, and zeolite are known. On the other hand, the polymer gas separation membrane is attracting attention because of its excellent permeability and workability.

  In view of the high temperature of the exhaust gas, the polymer gas separation membrane preferably has high heat resistance. For example, Patent Literatures 1 to 3 disclose polycarbonate-based gas separation membranes having relatively high carbon dioxide selective separation. However, these polycarbonate gas separation membranes have insufficient heat resistance.

  Non-Patent Documents 1 and 2 include 2-hydro-3,3-bis (4-hydroxyphenyl) phthalimidine or 2-phenyl-3,3-bis (4-hydroxyphenyl) phthalimidine and terephthalic acid or isophthalate. An acid polyarylate resin is disclosed. However, it is not described that these polyarylate resins are made into a film, and further that the film is used as a polymer gas film.

JP-A 48-64199 JP-A-10-99666 JP 2002-239357 A

Journal of Polymer Science: Polymer Chemistry Edition, (1981) Vol. 19, pp. 2659-2670 Journal of Polymer Science, 2 (A), pp 437-459 (1964)

  An object of the present invention is to provide a polyarylate resin film excellent in selective separation of carbon dioxide gas and heat resistance.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved by using a polyarylate resin having a specific dihydric phenol skeleton, and have reached the present invention.

That is, the gist of the present invention is as follows.
(1) A film comprising a polyarylate resin comprising a dihydric phenol component containing 10 mol% or more of the dihydric phenol represented by the chemical formula (1) and an aromatic dicarboxylic acid component.
(2) The film according to (1), which contains terephthalic acid and isophthalic acid as the aromatic dicarboxylic acid component.
(3) A gas separation membrane comprising the film according to (1) or (2).

  ADVANTAGE OF THE INVENTION According to this invention, the polyarylate resin film excellent in the selective separability of carbon dioxide gas and heat resistance can be provided.

  The polyarylate resin of the present invention is composed of a dihydric phenol component and an aromatic dicarboxylic acid component.

As a dihydric phenol component, it is necessary to contain the compound (2-hydro-3,3-bis (4-hydroxyphenyl) phthalimidine) represented by the chemical formula (1). When the compound represented by the chemical formula (1) is not contained, the heat resistance is lowered, which is not preferable. Note that the hydrogen atom on the aromatic ring in the chemical formula (1) may be substituted with a halogen atom, a hydrocarbon group, or the like. Since the compound represented by the chemical formula (1) has a bulky structure, the thermal motion of the polymer main chain can be suppressed, and many microvoids can be created in the polymer. Since the speeds of carbon dioxide gas and nitrogen gas passing through the microvoids are different, both can be separated. Moreover, since it has a bulky structure, solvent solubility is high, and also because it has many aromatic rings, its glass transition temperature is high. The compound represented by the chemical formula (1) can be synthesized, for example, according to the method described in Non-Patent Document 1.

The content of the compound represented by the chemical formula (1) needs to be 10 mol% or more, preferably 20 mol% or more, and preferably 40 mol% or more with respect to the total dihydric phenol component. Is preferable from the viewpoints of heat resistance and gas selectivity. When the content of the compound represented by the chemical formula (1) is less than 10%, the heat resistance and the selective separation of carbon dioxide gas are lowered, which is not preferable.

  Other dihydric phenols constituting the dihydric phenol component include 2,2-bis (4-hydroxyphenyl) propane [bisphenol A] and 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane. 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane [bisphenol AP], 1,1-bis (4-hydroxyphenyl) Cyclohexane [bisphenol Z], 1,1-bis (4-hydroxyphenyl) ethane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) ethane, 1,1-bis (3-methyl-4-) Hydroxyphenyl) ethane, bis (4-hydroxyphenyl) methane, bis (3,5-dimethyl-4-hydroxyphenyl) methane Bis (3-methyl-4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) hexane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) hexane, 1,1-bis (3-methyl-4-hydroxyphenyl) hexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethyl-cyclohexane, 1,1-bis (3,5-dimethyl-4-hydroxyphenyl) ) -3,3,5-trimethyl-cyclohexane, 1,1-bis (3,5-diphenyl-4-hydroxyphenyl) -3,3,5-trimethyl-cyclohexane, 1,1-bis (3-methyl-) 4-hydroxyphenyl) -3,3,5-trimethyl-cyclohexane, 1,1-bis (3-phenyl-4-hydroxyphenyl) -3,3,5-tri Tyl-cyclohexane, 1,1-bis (3,5-dichloro-4-hydroxyphenyl) -3,3,5-trimethyl-cyclohexane, 1,1-bis (3,5-dibromo-4-hydroxyphenyl)- 3,3,5-trimethyl-cyclohexane, 1,1-bis (4-hydroxyphenyl) cyclohexane [bisphenol Z] and the like.

  The dihydric phenol component may contain a compound having two other hydroxyl groups as long as the effects of the present invention are not impaired.

  Among these, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 1,1-bis (4-hydroxyphenyl)-is preferable because it has excellent heat resistance, solvent solubility, and carbon dioxide selective separation. 1-phenylethane [bisphenol AP] and 1,1-bis (4-hydroxyphenyl) cyclohexane [bisphenol Z] are preferred. These may be used alone or in combination of two or more.

  Examples of the aromatic dicarboxylic acid component include terephthalic acid, isophthalic acid, diphenyl ether-2,2′-dicarboxylic acid, diphenyl ether-2,3′-dicarboxylic acid, diphenyl ether-2,4′-dicarboxylic acid, diphenyl ether-3,3 ′. -Dicarboxylic acid, diphenyl ether-3,4'-dicarboxylic acid, diphenyl ether-4,4'-dicarboxylic acid, terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, bis (p-carboxyphenyl) diphenate Alkane, diphenyl ether-2,2'-dicarboxylic acid, diphenyl ether-2,3'-dicarboxylic acid, diphenyl ether-2,4'-dicarboxylic acid, diphenyl ether-3,3'-dicarboxylic acid, diphenyl ether-3,4'-dicarboxylic , Diphenyl ether-4,4'-dicarboxylic acid. Among them, it is preferable to use terephthalic acid and isophthalic acid in combination because the solvent solubility becomes high and the film can be easily produced by the casting method.

  When terephthalic acid and isophthalic acid are used in combination, the content ratio of both is preferably 10/90 to 90/10 (molar ratio), more preferably 25/75 to 75/25 (molar ratio), More preferably, it is 35/65 to 65/35 (molar ratio).

  The aromatic dicarboxylic acid component may contain an aliphatic dicarboxylic acid or an alicyclic dicarboxylic acid as long as the effects of the present invention are not impaired.

  The inherent viscosity of the polyarylate resin is preferably more than 0.5 and 1.5 or less. The inherent viscosity can be controlled by the amount of the end-capping agent added. When the inherent viscosity is 0.5 or less, cracking may occur when the film is peeled off from the base material in the casting method, or the film may not be extruded in the T-die method. On the other hand, when the inherent viscosity exceeds 1.5, the solution viscosity becomes high in the casting method and a film may not be formed, or the extrusion of the film may become difficult in the T-die method.

  The terminal acid value of the polyarylate resin is preferably 50 mol / ton or less, and more preferably 20 mol / ton or less. By setting the terminal acid value to 50 mol / ton or less, the solvent solubility is improved, and a film can be produced by a casting method. Generally, the higher the terminal acid value, the worse the solvent solubility.

  Examples of the method for producing the polyarylate resin include an interfacial polymerization method and a solution polymerization method. Since the interfacial polymerization method is faster than the solution polymerization method, hydrolysis of the acid halide can be suppressed, and as a result, a high molecular weight polymer can be obtained.

  As the interfacial polymerization method, a solution in which a divalent carboxylic acid halide is dissolved in an organic solvent incompatible with water (organic phase) is mixed with an aqueous alkaline solution containing a dihydric phenol, a terminal blocking agent, an antioxidant and a polymerization catalyst ( And a method of conducting a polymerization reaction while stirring at a temperature of 50 ° C. or lower for 1 to 8 hours.

  As the solvent used for the organic phase, a solvent that is not compatible with water and dissolves the polyarylate resin is preferable. Examples of such a solvent include methylene chloride and chloroform. Methylene chloride is preferred because it is easy to use in production.

  Examples of the aqueous alkali solution used in the aqueous phase include aqueous solutions of sodium hydroxide and potassium hydroxide.

  Examples of the end capping agent include monohydric phenol, monohydric acid chloride, monohydric alcohol, monohydric carboxylic acid and the like. As monohydric phenol, phenol, o-cresol, m-cresol, p-cresol, p-tert-butylphenol, o-phenylphenol, m-phenylphenol, p-phenylphenol, o-methoxyphenol, m-methoxyphenol P-methoxyphenol, 2,3,6-trimethylphenol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol , 2-phenyl-2- (4-hydroxyphenyl) propane, 2-phenyl-2- (2-hydroxyphenyl) propane, 2-phenyl-2- (3-hydroxyphenyl) propane and the like, and monovalent acid As chloride, benzoyl chloride, benzoic acid chloride Methanesulfonyl chloride, phenyl chloroformate and the like can be mentioned. As monohydric alcohol, methanol, ethanol, n-propanol, isopropanol, n-butanol, 2-butanol, pentanol, hexanol, dodecyl alcohol, stearyl alcohol, benzyl alcohol Phenethyl alcohol, and the like. Examples of monovalent carboxylic acids include acetic acid, propionic acid, octanoic acid, cyclohexanecarboxylic acid, benzoic acid, toluic acid, phenylacetic acid, p-tert-butylbenzoic acid, p-methoxyphenylacetic acid, and the like. Is mentioned. Among these, p-tert-butylphenol is preferable from the viewpoints of reactivity and thermal stability.

  Examples of the antioxidant include sodium hydrosulfite, L-ascorbic acid, erythorbic acid, catechin, tocophenol, butylhydroxyanisole and the like, and hydrosulfite sodium is preferred because it quickly dissolves in water.

  The polymerization catalyst includes quaternary ammonium salts such as tributylbenzylammonium halide, tetrabutylammonium halide, trimethylbenzylammonium halide, triethylbenzylammonium halide, tributylbenzylphosphonium halide, tetrabutylphosphonium halide, trimethylbenzylphosphonium halide, triethylbenzyl. Quaternary phosphonium salts such as phosphonium halides may be mentioned. Among them, tributylbenzylammonium halide, tetrabutylammonium halide, tributylbenzylphosphonium halide, and tetrabutylphosphonium halide are preferable in that a polymer having a high molecular weight and a low terminal acid value can be obtained.

  The film of the present invention can be obtained by processing a polyarylate resin by a casting method or a T-die method. The casting method is a method in which a resin is dissolved in an organic solvent, the resin solution is applied to a substrate, dried, and then peeled off from the substrate to produce a film. On the other hand, the T-die method is a method in which a dried resin is put into an extruder and a molten resin is extruded from a T-die to a cooling roll and scraped off. It is preferable to produce a film by a casting method because color tone deterioration due to thermal decomposition does not occur.

  Examples of the organic solvent used in the casting method include chloroform and methylene chloride, and examples of the substrate include PET film, polyimide film, and glass. The drying method is not particularly limited, but it is preferable to dry by heating in order to efficiently remove the organic solvent. The drying temperature and drying time are appropriately selected depending on the physical properties of the resin and the combination of the coated substrates. In consideration of economy, the drying temperature is preferably 40 to 150 ° C., more preferably 40 to 100 ° C., and the drying time is preferably 1 to 30 minutes, and 3 to 15 minutes. It is more preferable. In addition, you may dry naturally at room temperature as needed. Application method is not particularly limited, but wire bar coater coating, film applicator coating, brushing and spray coating, gravure roll coating method, screen printing method, reverse roll coating method, lip coating, air knife coating method, curtain flow coating method, A dip coating method can be used.

  In the T-die method, the conditions are not particularly limited, but the melting temperature of the resin is preferably a temperature range of (glass transition temperature + 100 ° C.) or lower, and the temperature of the cooling roll is 40 to 90 ° C. Is preferred. As a method of bringing the film into close contact with the cooling roll, a known method such as an electrostatic application method or an air knife method can be used.

For industrial production, the tensile strength of the film is preferably 45 MPa or more, and more preferably 70 MPa or more.
Moreover, in the film of this invention, since the compound of Chemical formula (1) contains 10 mol% or more as a dihydric phenol component, an elasticity modulus becomes high. Specifically, it can be set to 1950 MPa or more.

  Since the film of the present invention has a high ratio of carbon dioxide gas permeability coefficient to nitrogen gas permeability coefficient, which will be described later (hereinafter may be abbreviated as “carbon dioxide selective separation coefficient”), the carbon dioxide gas is selectively separated. Are better. In order to use industrially as a carbon dioxide separation membrane, the carbon dioxide selective separation coefficient may be 31.0 or more.

  Since the film of the present invention has high tensile strength and excellent carbon dioxide selective separation and heat resistance, it can be used as various separation membranes.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

1. Evaluation Item (1) Inherent Viscosity Polyarylate resin was dissolved in phenol / 1,1,2,2-tetrachloroethane (6/4 (mass ratio)) to prepare a sample solution having a concentration of 1 g / dl. Subsequently, the drop time of the sample solution and the solvent was measured at a temperature of 30 ° C. using an Ubbelohde viscometer, and the inherent viscosity was determined using the following equation.
Inherent viscosity = ln [(sample solution drop time / solvent only drop time) / resin concentration (g / dl)]

(2) Terminal acid value 150 mg of polyarylate resin was dissolved by heating in 5 ml of benzyl alcohol, and after cooling, mixed with 10 ml of chloroform. The solution was titrated with 0.1N potassium hydroxide benzyl alcohol solution using phenol red as an indicator. Using the titrated value, the number of equivalents contained in 1 ton of polyarylate resin was calculated and used as the terminal acid value.

(3) Glass transition temperature Using a polyarylate resin 10 mg as a sample, the temperature was raised using a DSC (Differential Scanning Calorimetry) apparatus (DSC7 manufactured by PerkinElmer Co., Ltd.) at a temperature rising rate of 10 ° C./min. An intermediate value between two bending point temperatures derived from the glass transition was taken as the glass transition temperature.

(4) Solvent solubility Polyarylate resin was mixed with chloroform so that the solute concentration was 15% by mass and stirred at 25 ° C. for 1 day. When a colorless transparent solution was obtained by dissolution after stirring, the solution was allowed to stand at 25 ° C. for 7 days. If the solution was colorless and transparent at this time, the solution was further allowed to stand at the same temperature for 24 hours. The solution state over time was visually observed and evaluated according to the following criteria.
A: A colorless and transparent solution was obtained immediately after stirring, and it was colorless and transparent after standing for 7 days.
◯: A colorless and transparent solution was obtained immediately after stirring. The solution was colorless and transparent after standing for 1 day, but was cloudy after standing for 48 hours.
Δ: A colorless transparent solution was obtained immediately after stirring, but it was cloudy after standing for 1 day.
X: Not dissolved.

(5) Tensile strength and tensile elastic modulus Tensile strength and tensile elastic modulus at the breaking point of a film having a thickness of 100 μm were measured using an Intesco tensile / compression tester in accordance with JIS K-2318.

(6) Total light transmittance The total light transmittance in wavelength 350nm was measured for the film of thickness 50 micrometers using the Nippon Denshoku Industries Co., Ltd. turbidimeter NDH2000. Practically, 85% or more is preferable.

(7) Carbon dioxide permeation coefficient, nitrogen gas permeation coefficient, carbon dioxide selective separation coefficient Using a gas permeation coefficient measuring apparatus GTR-10 manufactured by Yanagimoto Seisakusho Co., Ltd., a film having a thickness of 40 μm, the permeation coefficient of carbon dioxide and nitrogen gas at 25 ° C. Was measured.
A value obtained by dividing the carbon dioxide permeability coefficient by the nitrogen gas permeability coefficient was defined as the carbon dioxide selective separation coefficient.

2. Synthesis of Raw Material 2-Phenyl-3,3-bis (4-hydroxyphenyl) phthalimidine In a reaction vessel equipped with a Dean Stark apparatus, 31.8 parts by mass of phenolphthalein, 65 parts by mass of aniline and 20.5 parts by mass of concentrated hydrochloric acid Then, it was heated to 160 ° C. to volatilize water. Thereafter, the reaction was carried out for 15 hours without changing the temperature, and then the reaction mixture was poured into a reaction vessel containing 400 parts by mass of hydrochloric acid to produce a precipitate. The precipitate was collected by filtration, dissolved in an aqueous sodium hydroxide solution containing activated carbon, stirred for 30 minutes, and the activated carbon was removed by filtration to obtain a filtrate. Thereafter, the same activated carbon treatment was performed once more. Concentrated hydrochloric acid was added to the obtained filtrate for neutralization to form a precipitate. After filtration, the crude product was removed. 100 parts by mass of the crude product and 400 parts by mass of methanol were mixed, heated and refluxed for 1 hour, and then 2-phenyl-3,3-bis (4-hydroxyphenyl) phthalimidine was obtained by filtration.

Example 1
In a reaction vessel equipped with a stirrer, 74.0 parts by mass of 2-phenyl-3,3-bis (4-hydroxyphenyl) phthalimidine, 0.85 parts by mass of p-tert-butylphenol as an end-capping agent, and as an alkali 22.9 parts by mass of sodium hydroxide, 0.41 part by mass of triethylbenzylammonium chloride as a polymerization catalyst and 0.37 part by mass of hydrosulfite sodium as an antioxidant were charged and dissolved in 1750 parts by mass of water (aqueous phase). Separately, 19.76 parts by mass of terephthalic acid chloride (hereinafter abbreviated as TPC) and 19.76 parts by mass of isophthalic acid chloride (hereinafter abbreviated as IPC) are dissolved in 1000 parts by mass of methylene chloride. (Organic phase) (TPC: IPC = 50: 50 (molar ratio)). The aqueous phase was previously stirred, and the organic phase was added to the aqueous phase under strong stirring, and polymerization was performed at 15 ° C. for 4 hours by the interfacial polymerization method. Thereafter, stirring was stopped, and the aqueous phase and the organic phase were decanted and separated. After removing the aqueous phase, 500 parts by mass of methylene chloride, 2000 parts by mass of pure water and 2 parts by mass of acetic acid were added to stop the reaction, and the mixture was stirred at 15 ° C. for 30 minutes. Thereafter, the organic phase was washed 10 times with pure water, and the organic phase was added into methanol to precipitate the polymer. The precipitated polymer was filtered and dried to obtain a polyarylate resin.
The obtained polyarylate resin was dissolved in chloroform to a concentration of 15% by mass to obtain a chloroform solution. The obtained chloroform solution was cast-coated on a glass plate and dried under reduced pressure at 120 ° C. for 24 hours to produce a film having a predetermined thickness.

Examples 2 to 9, 12 and Comparative Examples 1 to 3
A polyarylate resin was polymerized in the same manner as in Example 1 except that the monomer used was changed as shown in Table 1 to obtain a film.

Examples 10, 11, 13
A polyarylate resin was obtained in the same manner as in Example 1 except that the monomers were changed as shown in Table 1, and then melted at 330 ° C. and extruded from a T-die onto a cooling roll set at 50 ° C. Was made.

  Table 1 shows the resin composition, resin characteristics, and film characteristics.

  The films of Examples 1 to 13 were excellent in carbon dioxide separation and heat resistance.

Since the films of Comparative Examples 1 and 2 used the polyarylate resin not containing dihydric phenol represented by the chemical formula (1), the carbon dioxide selective separation factor was low.
Since the film of Comparative Example 3 used a polyarylate resin having a low dihydric phenol content represented by the chemical formula (1), the heat resistance was low and the carbon dioxide selective separation factor was low.

Claims (3)

A film comprising a polyarylate resin comprising a dihydric phenol component containing 10 mol% or more of the dihydric phenol represented by the chemical formula (1) and an aromatic dicarboxylic acid component.
The film according to claim 1, comprising terephthalic acid and isophthalic acid as the aromatic dicarboxylic acid component. A gas separation membrane comprising the film according to claim 1.