Total aromatic polyamide solution, and method for producing a total aromatic polyamide solution

Abstract

To provide a wholly aromatic polyamide solution without the combined use of inorganic salts, organic salts or the like with non-protonic organic polar solvents.SOLUTION: A wholly aromatic polyamide solution comprises wholly aromatic polyamides, and at least one of the solvents (a)-(c) described below. In the wholly aromatic polyamide solution, the content of salts containing ions derived from inorganic compounds is 10,000 PPM or less. (a) A co-solvent containing 10 mass% or more of an organic strong base and a non-protonic organic solvent. (b) A salt synthesized from an organic strong base and a protonic solvent. (c) An ionic liquid synthesized from an organic strong base and a protonic solvent.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an all-aromatic polyamide solution containing an all-aromatic polyamide, a solvent containing an organic strong base, or a salt synthesized from an organic strong base and a protic solvent, or an ionic liquid synthesized from an organic strong base and a protic solvent, and a method for producing the all-aromatic polyamide solution.

Background Art

[0002] An all-aromatic polyamide (aramid) is a polyamide containing an aromatic structure, and there are para-aramid and meta-aramid. Examples of para-aramid fibers include poly(p-phenylene terephthalamide) fibers (DuPont's "Kevlar" (registered trademark), Teijin's "Twaron" (registered trademark)), copoly(p-phenylene-3,4'-oxydiphenylene terephthalamide) fibers (Teijin's "Technora" (registered trademark)), etc. Such para-aramids have low solubility and dissolve only in a determined solvent (concentrated sulfuric acid). However, sulfuric acid is a harmful substance and may pose a danger to workers. It also has high metal corrosiveness and can cause process piping corrosion, etc.

[0003] Patent Documents 1 to 3 disclose a method of dissolving in a solvent in which an inorganic salt such as lithium chloride or calcium chloride is dissolved in an aprotic polar organic solvent such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), or hexamethylphosphoramide (HMPA).

[0004] Generally, in order to coagulate a polymer from a polymer solution, it is necessary to use a poor solvent such as water. However, in a solvent system using an aprotic organic polar solvent and an inorganic salt or an organic salt such as a quaternary ammonium salt, separation and recovery of three or more components, namely, the aprotic organic polar solvent, the inorganic salt or the organic salt such as the quaternary ammonium salt, and the poor solvent such as water, are required.

[0005] Therefore, Patent Document 4 discloses a method for recovering an aprotic organic polar solvent from an aqueous solution consisting of an aprotic organic polar solvent, an inorganic salt, and an organic salt. However, this method includes steps such as extraction with a halogen-based solvent and distillation of the halogen-based solvent, which has the problem of complicating the recovery process. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 52-46982 [Patent Document 2] Japanese Patent Application Publication No. 4-226533 [Patent Document 3] Japanese Patent Publication No. 2006-241624 [Patent Document 4] Japanese Patent Publication No. 2002-1008 [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to solve the problems of the prior art and to provide a fully aromatic polyamide solution that does not require the use of inorganic salts, organic salts, etc., in combination with a non-protic organic polar solvent, and therefore the recovery process, such as the step of extraction with a halogen-based solvent and the step of distillation of the halogen-based solvent, can be simplified. [Means for solving the problem]

[0008] As a result of diligent research to solve the above problems, the inventors of the present invention have found that when using a solvent containing a cosolvent comprising an organic strong base and an aprotic organic solvent, or a salt comprising an organic strong base and a protic solvent, or an ionic liquid comprising an organic strong base and a protic solvent, a fully aromatic polyamide solution can be provided without using inorganic salts or organic salts, thus completing the present invention.

[0009] In other words, according to the present invention, 1. All aromatic polyamides and the following (a)~( b A fully aromatic polyamide solution containing at least one of the solvents described in any of the above, characterized in that the content of a salt containing ions derived from an inorganic compound contained in the fully aromatic polyamide solution is 10,000 PPM or less. (a) Salts synthesized from organic strong bases and protic solvents (b) Ionic liquids synthesized from organic strong bases and protic solvents 2. As described in item 1 above ( a ) Salts synthesized from organic strong bases and protic solvents ( b ) Ionic liquids synthesized from organic strong bases and protic solvents The all-aromatic polyamide solution described in item 1 above, further containing an aprotic organic solvent, 3. The all-aromatic polyamide solution according to 1 above, which contains a eutectic mixture in the all-aromatic polyamide solution. 4. A method for producing fully aromatic polyamide fibers, characterized by using the fully aromatic polyamide solution described in item 1 above as a dope for wet spinning. , It will be provided. [Effects of the Invention]

[0010] According to the present invention, a fully aromatic polyamide solution can be provided that does not use inorganic salts, organic salts, etc., in combination with an aprotic organic polar solvent. Therefore, a fully aromatic polymer solution can be provided that simplifies recovery steps such as extraction with a halogen-based solvent and distillation of the halogen-based solvent. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below. The solvents used in this invention are components other than the polymer in the polymer solution, such as strong organic bases, aprotic organic solvents, protic solvents, salts, ionic liquids, and eutectic mixtures. The solvent ratio in this invention is the mass percentage of each solvent (strong organic base, aprotic organic solvent, protic solvent, salt, ionic liquid, or eutectic mixture) relative to the total solvent in the polymer solution.

[0012] <Organic strong bases> In the present invention, an organic strong base is a base made of an organic compound, and examples include amine-based, pyridine-based, heterocyclic amine-based, and phosphorus-based bases. In the present invention, an organic strong base is an organic base that exhibits strong basicity, and examples include guanidine, 1,1,3,3-tetramethylguanidine (TMG), 2-tert-butyl-1,1,3,3-tetramethylguanidine, diazabicyclononene (DBN), diazabicycloundecene (DBU), 1,5,7-triazabicyclo[4.4.0]deca-5-ene (TBD), 7-methyl-1,5,7-triazabicyclo[4.4.0]deca-5-ene (MTBD), 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine (DMP), fastfazen base, proazaphosphothorane base, and the like.

[0013] The acid dissociation constant pKa of the conjugate acid of the organic strong base of the present invention is preferably 10 or greater. The organic strong base in the present invention is preferably low in nucleophilicity and high in basicity, and diazabicyclononene (DBN), diazabicycloundecene (DBU), 1,5,7-triazabicyclo[4.4.0]deca-5-ene (TBD), 7-methyl-1,5,7-triazabicyclo[4.4.0]deca-5-ene (MTBD), and 1,2-dimethyl-1,4,5,6-tetrahydropyrimidine (DMP) are more preferred. Diazabicyclononene (DBN) and diazabicycloundecene (DBU) are even more preferred. Diazabicycloundecene (DBU) is the most preferred.

[0014] <Aprotic organic solvents> In this invention, aprotic organic solvents are solvents composed of organic compounds that do not have proton-donating groups such as hydroxyl groups, and include, for example, ethyl carbonate, propyl carbonate, ethyl fluorocarbonate, dimethyl carbonate, ethylmethyl carbonate, diethyl carbonate, 1,2-butylene carbonate, dimethyl sulfone, ethylmethyl sulfone, diethyl sulfone, dipropyl sulfone, sulfolane, dimethyl sulfide, diethyl sulfide, diisopropyl sulfide, dimethyl sulfoxide, diethyl sulfoxide, diethyl ether, propyl ether, isopropyl ether, and dibutyl ether. Tel, diisobutyl ether, cyclopentyl methyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, dioxane, dihydrolevoglucocenone, α-angelicalactone, γ-butyrolactone, γ-valerolactone, γ-caprolactone, γ-heptanolactone, γ-octanolactone, γ-nonalactone, γ-decanolactone, δ-valerolactone, δ-hexanolactone, δ-octanolactone, δ-decanolactone, δ-tetradecanolactone, ε-caprolactone, ε-decanolactone, Dimethyl isosorbide, acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, tert-butyl acetate, lauryl acetate, methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, isopropyl acetoacetate, butyl acetoacetate, isobutyl acetoacetate, tert-butyl acetoacetate, lauryl acetoacetate, methyl levulinate, ethyl levulinate, propyl levulinate, isopropyl levulinate, le Butyl brate, isobutyl levulinate, tert-butyl levulinate, dimethyl succinate, diethyl succinate, acetonitrile, succinonitrile, cumene, limonene, methylcyclohexane, dimethyl sulfoxide (DMSO), N-methylformamide, N-methylacetamide, N,N-dimethylformamide (DMF), N,N-diethylformamide, N,N-dipropylformamide, N,N-diisopropylformamide, N,N-dibutylformamide, N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N,N-dipropylacetamide, N,N-diisopropylacetamide, N,N-dibutylacetamide, N,N-dimethylacetacetamide, N,N-diethylacetacetamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, N,N-dimethyloctanamide, N,N-dimethyldecanamide, N,N-diethylhexaneamide, N,N-diethylbenzamide, N,N-diethyl-3-methylbenzamide, malonamide, pyrrolidine, N-acetyl-2 -Pyrrolidine, 2-pyrrolidone, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), 1-(2-hydroxyethyl)-2-pyrrolidone, 1-propylpyrrolidine-2-one, N-isopropyl-2-pyrrolidone, 1-butylpyrrolidine-2-one, N-isobutyl-2-pyrrolidone, N-tertbutyl-2-pyrrolidone, 1-cyclohydroxyl-2-pyrrolidone, 1-n-octyl-2-pyrrolidone, and other N-alkyl-2-pyrrolidones, N-vinylpyrrolidone, 3-bromo-N-methyl Pyrrolidone, 3-hydroxy-n-methylpyrrolidone, 5-hydroxy-N-methylpyrrolidone, 5-methyl-2-pyrrolidone, 1,5-dimethyl-2-pyrrolidone, 5-methyl-N-ethylpyrrolidone, 5-methyl-N-hydroxyethylpyrrolidone, 5-methyl-N-propylpyrrolidone, 5-methyl-N-isopropylpyrrolidone, 5-methyl-N-butylpyrrolidone, 5-methyl-N-isobutylpyrrolidone, 5-methyl-N-cyclohexylpyrrolidone, 5-methyl-N-phenylpyrrolidone, 5-ethyl- 2-pyrrolidone, 5-propyl-2-pyrrolidone, piperidine, 2,2,6,6-tetramethylpiperidine, 2-piperidone, 4-piperidone, N-methyl-2-piperidone, N-methyl-4-piperidone, N-ethyl-4-piperidone, 1,3-dimethyl-2-piperidone, 1,5-dimethyl-2-piperidone, 1,3-dimethyl-4-piperidone, ε-caprolactam, N-methyl-ε-caprolactam, N-vinyl-ε-caprolactam, 1-methylimidazole, 1,3-dimethyl-2-imidazolidinone, N,N-dimethylpropyleneurea, tetramethylurea, morpholine, 4-methylmorpholine, 4-ethylmorpholine, 4-propylmorpholine, 4-formylmorpholine, 4-acetylmorpholine, 1,4-diacetylpiperazine, N,N-dimethylglycine, N,N-diacetylglycine, pyridine, 2-hydroxypyridine, 2-methylpyridine, 4-methylpyridine, 3,4-dimethylpyridine, 2,6-lutidine, 4-dimethylaminopyridine, 1-methyl-2-pyridone, quinoline, 1-methyl-2-quinoline, hexamethylphosphoric triamide, 1,4-diazabicyclo[2.2.2]octane (DABCO), and the like can be mentioned.,

[0015] Regarding the co-solvent containing (a) an organic strong base of 10% by mass or more and an aprotic organic solvent, which is at least one solvent used in the present invention, the solvent ratio of the organic strong base to the total solvent needs to be 10% by mass or more and is preferably 99.9% by mass or less. More preferably, it is 90% by mass or less, still more preferably 80% by mass or less, and most preferably 30% by mass or more to 80% by mass or less. When the content ratio is less than 10% by mass or exceeds 99.9% by mass, the polymer solubility of the solvent becomes low, which is not preferable.,

[0016] <Protic solvent> The protic solvent in the present invention is a solvent having a hydroxyl group and capable of becoming a proton donor, and examples thereof include water, alcohol, amino acid, carboxylic acid, sulfonic acid, sugar, and the like.,

[0017] Although not particularly limited, for example, water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butyl alcohol, 1-pentanol, 1-hexanol, 2-ethylhexanol, cyclohexanol, 1-octanol, 2-methoxyethanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, glycerin, formic acid, acetic acid, propionic acid, 3-hydroxypropionic acid, butanoic acid, 3-hydroxybutanoic acid, lactic acid, succinic acid, levulinic acid, glycolic acid, oxalic acid, methyl lactate, ethyl lactate, propyl lactate, isopropyl lactate, butyl lactate, isobutyl lactate, 2-ethylhexyl lactate, sugars such as glucose, amino acids such as glycine, alanine, valine, leucine, isoleucine, methionine, tyrosine, tryptophan, phenylalanine, asparagine, cytosine, glutamine, serine, threonine, serine, maleimide, N-hydroxysuccinimide, etc. may be mentioned.

[0018] More preferably, water, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butyl alcohol, 1-pentanol, 1-hexanol, 2-ethylhexanol, cyclohexanol, 1-octanol, 2-methoxyethanol, ethylene glycol, glycerin, formic acid, acetic acid, propionic acid, 3-hydroxypropionic acid, etc. may be mentioned.

[0019] Furthermore, the present invention can also use protic solvents, aprotic organic solvents, and strong organic bases derived from plants and animals. Protic solvents and aprotic organic solvents derived from plants and animals refer to organic compounds synthesized from plant-derived raw materials (sugar / starch-based biomass, lignocellulosic biomass including cellulose, hemicellulose, and lignin), and natural products produced by plants, animals, and microorganisms. There is no difference in physical properties such as molecular weight and thermophysical properties (melting point, boiling point) between solvents derived from plants and animals and solvents derived from fossils. Therefore, biomass degree is generally used to distinguish between them.

[0020] Biomass content is a value measured by radiocarbon (¹⁴C, half-life 5730 years) measurement to determine the amount of carbon derived from biomass. In the upper atmosphere, ¹⁴N is converted to ¹⁴C by high-energy cosmic rays, so atmospheric carbon dioxide contains a certain amount of ¹⁴C. Carbon dioxide is fixed in plants as carbohydrates through photosynthesis, so plants contain a similar amount of ¹⁴C. On the other hand, fossil-derived petroleum contains virtually no ¹⁴C, so it is possible to distinguish between plant-derived carbon and fossil-derived carbon. Generally, ASTM D6866 is known as a method for measuring biomass content. Therefore, the organic solvents derived from plants and animals in this invention can also be distinguished by measuring the biomass content after extracting the organic solvent from the polymer solution.

[0021] While not particularly limited, specific plant and animal-derived solvents in this invention include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, glycerin, benzyl alcohol, furfuryl alcohol, tetrahydrofurfuryl alcohol, formic acid, acetic acid, 3-hydroxypropionic acid, butanoic acid, 3-hydroxybutanoic acid, lactic acid, succinic acid, levulinic acid, glycolic acid, acrylic acid, oxalic acid, dimethyl sulfone, dimethyl sulfoxide, diethyl ether, propyl ether, and isopropyl ether. Dibutyl ether, diisobutyl ether, cyclopentyl methyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 2,5-dimethyltetrahydrofuran, dihydrolevoglucocenone, diformylxylose, γ-butyrolactone, γ-valerolactone, δ-valerolactone, δ-decanolactone, ε-caprolactone, dimethylisosorbide, acetone, cyclopentanone, ethyl acetate, ethyl lactate, propyl lactate, isopropyl lactate, butyl lactate, isobutyl lactate, 2-ethylhexyl lactate, methyl levulinate, ethyl levulinate, propyl levulinate, propyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate, vinyl ethylene carbonate, 1,2-butylene carbonate, glycerol 1,2-carbonate, acetonitrile, succinonitrile, N,N-dimethylacetamide (DMAc), 2-pyrrolidone, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), 1-(2-hydroxyethyl)-2-pyrrolidone, 1-propylpyrrolidine-2-one, 1-isopropylpyrrolidine-2-one, 1-butylpyrrolidine-2-one, 1-isobutylpyrrolidine-2-one, 1-pentylpyrrolidine-2-one, 1-isopentylpyrrolidine-2-one, 1-n-octyl-2-pyrrolidone, N-alkyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 1-(2-hydroxyethyl)-2-pyrrolidone, 5-methyl-2-pyrrolidone, 1,5-dimethylethyl Examples include amino acids such as 2-pyrrolidone, 5-methyl-N-ethylpyrrolidone, 5-methyl-N-hydroxyethylpyrrolidone, 5-methyl-N-propylpyrrolidone, 5-methyl-N-isopropylpyrrolidone, 5-methyl-N-butylpyrrolidone, 5-methyl-N-isobutylpyrrolidone, 5-methyl-N-cyclohydroxylpyrrolidone, 5-methyl-N-phenylpyrrolidone, N-methylcaprolactam, 2,6-lutidine, glycine, alanine, valine, leucine, isoleucine, methionine, tyrosine, tryptophan, phenylalanine, asparagine, cytosine, glutamine, serine, threonine, and serine.

[0022] <Salts, ionic liquids> In the present invention, (b) Salts synthesized from a strong organic base and a protic solvent (c) Ionic liquids synthesized from organic strong bases and protic solvents At least one of the following can be used as a solvent.

[0023] Salts are generally compounds produced by the neutralization reaction of an acid and a base, and are compounds in which an anion derived from the acid and a cation derived from the base are ionically bonded. Inorganic salts are compounds in which an anion derived from an inorganic acid and a cation derived from an inorganic base are bonded. Examples of inorganic salts include lithium chloride, calcium chloride, potassium nitrate, and potassium sulfate.

[0024] On the other hand, organic salts are compounds in which either the acid or the base is derived from an organic compound. Examples include lithium acetate, ammonium acetate, potassium propionate, tetramethylammonium chloride, tetrabutylammonium fluoride, tetrabutylammonium bromide, and collinchloride.

[0025] Furthermore, it is known that copolymer p-phenylene-3,4'-oxydiphenylene terephthalamide fibers can be dissolved by adding 3.2 to 10.5% by mass of an inorganic salt such as calcium chloride to an amide-based organic solvent. However, as mentioned above, this method involves steps such as extracting the inorganic salt with a halogen-based solvent and distilling the halogen-based solvent, which complicates the recovery process.

[0026] Therefore, in the present invention, by using the solvents described in (a) to (c) above, a fully aromatic polyamide solution can be obtained without using a salt containing ions derived from inorganic compounds. Here, "not using a salt containing ions derived from inorganic compounds" means that the content of a salt containing ions derived from inorganic compounds in the solvent used in the present invention is 10,000 PPM or less, more preferably 1,000 PPM or less relative to the solvent, and even more preferably 100 PPM or less. If the content of a salt containing ions derived from inorganic compounds exceeds 10,000 PPM, the effects of the present invention cannot be obtained.

[0027] In this invention, an ionic liquid is a salt having a melting point of 100°C or lower. Examples of ionic liquids include aprotic ionic liquids, protic ionic liquids, chelate ionic liquids, and inorganic ionic liquids.

[0028] Aprotic ionic liquids are ionic liquids that do not possess active protons. Their cations include imidazolium, quaternary ammonium, quaternary phosphonium, and tertiary phosphonium, while their anions are bulky combinations of ions with delocalized charges. Furthermore, protic ionic liquids are ionic liquids that contain active protons and can be obtained by the neutralization reaction of Brønsted acids and Brønsted bases.

[0029] In the present invention, the solvents described in (b) or (c) above can be used, but salts and ionic liquids synthesized from an organic strong base with water, alcohol, or carboxylic acid are preferred. More preferably, salts and ionic liquids containing an organic strong base, one or more selected from water or alcohol, and at least one selected from the group consisting of carbon dioxide, carbon disulfide, sulfur dioxide, and hydrogen sulfide, or salts and ionic liquids containing an organic strong base and a carboxylic acid are preferred. Particularly preferred are salts obtained from diazabicycloundecene (DBU), an organic strong base, water, and carbon dioxide; salts obtained from DBU, methanol, and carbon dioxide; salts obtained from DBU, ethanol, and carbon dioxide; salts obtained from DBU, 1-propanol, and carbon dioxide; salts obtained from DBU, 2-propanol, and carbon dioxide; salts obtained from DBU and formic acid; ionic liquids obtained from DBU and acetic acid; and ionic liquids obtained from DBU and propionic acid.

[0030] In the present invention, the solvent ratio of the salt synthesized from an organic strong base and a protic solvent, or the ionic liquid, to the total solvent is preferably 0.01 to 100% by mass. More preferably 0.1 to 100% by mass. Even more preferably 1.0 to 100% by mass. If the solvent ratio is below 0.01% by mass, the solubility of the polymer solution will be low, which is undesirable. Furthermore, in the present invention, the solvent of (b) or (c) described above may also contain an aprotic organic solvent.

[0031] <eutectic mixture> In this invention, a eutectic mixture is a mixture in which the melting point of one or more hydrogen bond donors and one or more hydrogen bond acceptors is lowered by mixing them, resulting in a lower melting point than that of the individual substances.

[0032] For example, 4-aminobenzoic acid and colinchloride, malic acid and alanine, malic acid and glycine, malic acid and proline, oxalic acid and histidine, oxalic acid and proline, urea and acetamide, ε-caprolactam and acetamide, urea and ε-caprolactam, urea and colinchloride, urea and choline bromide, urea and betaine hydrochloride, glycerin and colinchloride, thiourea and colinchloride, TMG and thiourea, DBN and thiourea, DBU and thiourea, DBU and methylthiourea, DBU and methylthiourea Combinations such as luthiourea, DBU and trimethylthiourea, DBU and lithium nitrate, DBU and bis(trifluoromethanesulfonyl)imide lithium, DBU, dimethylurea and ethylene glycol, glycerin, DBU and collinchloride, glycerin, DBN and collinchloride, DBU, imidazole ionic liquid and ethylene glycol, DBU, indole ionic liquid and ethylene glycol, and DBU, 1,2,4-triazole ionic liquid and ethylene glycol have been reported. The polymer solution of the present invention may contain a eutectic mixture.

[0033] <Deep eutectic solvent> The deep eutectic solvent in this invention is a mixture in which the eutectic melting point is lowered and the mixture becomes liquid at room temperature by mixing one or more hydrogen bond donors and hydrogen bond acceptors in a certain mixing ratio.

[0034] For example, malic acid and alanine (molar ratio 1:1), malic acid and glycine (molar ratio 1:1), malic acid and proline (molar ratio 1:2), oxalic acid and histidine (molar ratio 9:1), oxalic acid and proline (molar ratio 1:1), urea and acetamide (molar ratio 1:2), ε-caprolactam and acetamide (molar ratio 1:1), urea and ε-caprolactam (molar ratio 1:3), urea and colinchloride (molar ratio 2:1), urea and choline bromide (molar ratio 2:1), urea and betaine hydrochloride (molar ratio 4:1), glycerin and colinchloride (molar ratio 2:1), thiourea and colinchloride (molar ratio 2:1), TMG and thiourea (molar ratio 2:1), DBN and thiourea (molar ratio 2:1), DBU and thiourea (molar ratio Combinations such as DBU and methylthiourea (molar ratio 2:1), DBU and dimethylthiourea (molar ratio 2:1), DBU and trimethylthiourea (molar ratio 2:1), DBU and lithium nitrate (molar ratio 3:1), DBU and bis(trifluoromethanesulfonyl)imide lithium (molar ratio 4:1), glycerin, DBU and collinchloride (molar ratio 1:2:6), glycerin, DBN and collinchloride (molar ratio 1:2:6), DBU, imidazole ionic liquid and ethylene glycol (molar ratio 7:3), DBU, indole ionic liquid and ethylene glycol (molar ratio 7:3), and DBU, 1,2,4-triazole ionic liquid and ethylene glycol (molar ratio 7:3) have been reported. The polymer solution of the present invention may contain a deep eutectic solvent.

[0035] <Total aromatic polyamide> The polymer solution of the present invention can be suitably used, in particular, when regenerating fully aromatic polyamides. All-aromatic polyamides are polymers in which one or more divalent or higher aromatic groups are directly linked by amide bonds. Furthermore, benzene rings may be bonded to the aromatic groups at the para or meta position. These divalent or higher aromatic groups may include lower alkyl groups such as methyl and ethyl groups, halogen groups such as methoxy and chlor groups, and cyano groups.

[0036] Furthermore, all-aromatic polyamides are classified into para-type and meta-type. Para-type all-aromatic polyamides are all-aromatic polyamides whose main component is a para-type all-aromatic polyamide consisting of a para-type aromatic dicarboxylic acid chloride component and a para-type aromatic diamine component, where the main component refers to a total repeating unit of 50 mol% or more. Meta-type all-aromatic polyamides are all-aromatic polyamides whose main component is a meta-type all-aromatic polyamide consisting of a meta-type aromatic dicarboxylic acid chloride component and a meta-type aromatic diamine component, where the main component refers to a total repeating unit of 50 mol% or more.

[0037] [Raw materials for all aromatic polyamides] (Aromatic carboxylic acid chloride component) Aromatic carboxylic acid chloride components used in the above-mentioned all-aromatic polyamides include isophthalic acid chloride, terephthalic acid chloride, 2,6-naphthalenedicarboxylic acid chloride, 2,5-franglicarboxylic acid chloride, 3,4-franglicarboxylic acid chloride, pyridine-2,6-dicarboxylic acid chloride, 1,3,5-benzenedicarboxylic acid dichloride, 2,2'-bis(5-chloroformyl 2-furyl)propane, and 2-pyrone-4,6-dicarboxylic acid dichloride. Derivatives having substituents such as halogens, alkoxy groups with 1 to 3 carbon atoms, sulfonic acid groups, or sodium sulfonate groups on the aromatic ring, such as 3-chloroisophthalic acid chloride and 3-methoxyisophthalic acid chloride, may also be used.

[0038] (Aromatic amine components) Aromatic amine components used in the above-mentioned all-aromatic polyamides include metaphenylenediamine, paraphenylenediamine, 1,5-diaminonaphthalene, 2,6-diaminonaphthalene, 1,8-diaminonaphthalene, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl sulfone, 4,4'-diaminobenzanilide, 2,5-bis(aminomethyl)furan, 1,3,5-benzenetriamine, 2,2'-bis(trifluoromethyl)benzidine, 3,5-diaminobenzoic acid, methyldavanillylamine, and 5-amino-2-(4-aminophenyl)benzimidazole. Furthermore, derivatives having substituents such as halogens, alkoxy groups having 1 to 3 carbon atoms, sulfonic acid groups, or sodium sulfonate groups on these aromatic rings may also be used, such as 2,4-toluylenediamine, 2,6-toluylenediamine, 2,4-diaminochlorobenzene, and 2,6-diaminochlorobenzene.

[0039] <Method for producing fully aromatic polyamides> The above-mentioned all-aromatic polyamides can be produced according to conventionally known methods. For example, they can be obtained by reacting an aromatic dicarboxylic acid dichloride (hereinafter also referred to as "acid chloride") component with an aromatic diamine component in an aprotic polar amide organic solvent by solution polymerization or interfacial polymerization.

[0040] (Polymerization solvent) Polymerization solvents used in the production of fully aromatic polyamides include the aprotic organic solvents mentioned above. These solvents can be used individually or as a mixture of two or more solvents. Organic solvents derived from plants and animals can also be used as polymerization solvents.

[0041] In the case of solution polycondensation, aprotic organic polar solvents are preferred from the viewpoint of the solubility of the total aromatic polyamide after polymerization, and amide organic solvents are more preferred from the viewpoint of reactivity. For example, N-methylformamide, N-methylacetamide, N,N-dimethylformamide (DMF), N,N-diethylformamide, N,N-dipropylformamide, N,N-diisopropylformamide, N,N-dibutylformamide, N,N-dimethylacetamide (DMAc), N,N-diethylacetamide, N,N-dipropylacetamide, N,N-diisopropylacetamide, N,N-dibutylacetamide, N,N-dimethylacetacetamide, N,N-diethylacetacetamide, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, N,N-dimethyloctanamide, N,N-dimethyldecanamide, N,N-diethylhexanamide, N,N-diethylbenzamide, N,N-diethyl-3-methylbenzamide, malonamide, pyrrolidine, N-acetyl-2-pyrrolidine, 2-pyrrolidone, N-methyl-2-pyrrolidone (NMP), N-ethyl-2-pyrrolidone (NEP), 1-(2-hydroxyethyl)-2-pyrrolidone, 1-propylpyrrolidine-2-one, N-isopropyl N-alkyl-2-pyrrolidones such as 2-2-pyrrolidone, 1-butylpyrrolidine-2-one, N-isobutyl-2-pyrrolidone, N-tertbutyl-2-pyrrolidone, 1-cyclohydroxyl-2-pyrrolidone, 1-n-octyl-2-pyrrolidone, N-vinylpyrrolidone, 3-bromo-N-methylpyrrolidone, 3-hydroxy-n-methylpyrrolidone, 5-hydroxy-N-methylpyrrolidone, 5-methyl-2-pyrrolidone, 1,5-dimethyl-2 -pyrrolidone, 5-methyl-N-ethylpyrrolidone, 5-methyl-N-hydroxyethylpyrrolidone, 5-methyl-N-propylpyrrolidone, 5-methyl-N-isopropylpyrrolidone, 5-methyl-N-butylpyrrolidone, 5-methyl-N-isobutylpyrrolidone, 5-methyl-N-cyclohexylpyrrolidone, 5-methyl-N-phenylpyrrolidone, 5-ethyl-2-pyrrolidone, 5-propyl-2-pyrrolidone, piperidine, 2, 2, 6, 6- Examples include tetramethylpiperidine, 2-piperidone, 4-piperidone, N-methyl-2-piperidone, N-methyl-4-piperidone, N-ethyl-4-piperidone, 1,3-dimethyl-2-piperidone, 1,5-dimethyl-2-piperidone, 1,3-dimethyl-4-piperidone, ε-caprolactam, N-methyl-ε-caprolactam, N-vinyl-ε-caprolactam, 1-methylimidazole, and 1,3-dimethyl-2-imidazolidinone. Alternatively, a mixed solvent with a strong organic base such as DBU or DBN, or an aprotic organic solvent such as tetrahydrofuran or 2-methyltetrahydrofuran may be used.

[0042] [Other polymerization conditions, etc.] The ends of the resulting all-aromatic polyamide can also be encapsulated. When encapsulating the ends using an end-capturing agent, for example, phthalate chloride and its derivatives, aniline and its derivatives, etc., can be used as end-capturing agents. In addition, aliphatic or aromatic amines can be used in combination to capture acids such as hydrogen chloride that are produced.

[0043] The polymer solution obtained by the above method for producing fully aromatic polyamides can be immersed in a poor solvent such as water and allowed to solidify (wet solidification), or dried to remove the solvent and allow the polymer to solidify (dry solidification) to obtain fully aromatic polyamides. It is also possible to obtain polymer compositions in the form of powder, fibride, thread, or film by wet or dry solidification. Alternatively, the polymer solution obtained by the above method for producing fully aromatic polyamides can be used as is.

[0044] The molecular weight of the polymer used in this invention is not particularly limited as long as it is sufficient to form polymer molded products such as threads, films, sheets, coated films, porous films, and particles, but it is preferably between 10,000 and 1,000,000. A molecular weight of less than 10,000 is undesirable because it results in low strength of the polymer molded product. A molecular weight of 1,000,000 or more is undesirable because it makes the polymer solution difficult to handle.

[0045] Furthermore, in addition to polyamides and fully aromatic polyamides, the polymer solution of the present invention may also use polymers blended with ultra-high molecular weight polyethylene, high-density polyethylene, low-density polyethylene, polypropylene, polyvinylidene fluoride, polyamide-imide, aromatic polyamide-imide, polyimide, etc.

[0046] [Method for producing polymer solutions] In the present invention, by dissolving the above-mentioned all-aromatic polyamide in at least one of the solvents described in (a) to (c) above, an all-aromatic polyamide solution can be obtained in which the salt content containing ions derived from inorganic compounds is 10,000 PPM or less. The polymer solution of the present invention may contain additives such as flame retardants, colorants, matting agents, lightfastness agents, and conductive agents to improve performance.

[0047] The polymer concentration in the polymer solution of the present invention is not particularly limited, but is preferably 0.1 to 30% by mass. More preferably it is 1 to 15% by mass. If the polymer concentration is less than 0.1% by mass, it becomes difficult to mold into filamentous or film-like forms, which is undesirable. If the polymer concentration exceeds 30% by mass, the polymer solution becomes difficult to handle, and the polymer does not dissolve completely, leading to precipitation, which is also undesirable.

[0048] [Method for preparing an inorganic particle-containing binder solution consisting of a polymer solution] The polymer solution of the present invention can also be used as a polymer solution containing inorganic particles (binder solution) by mixing inorganic particles with it. Examples of inorganic particles include wet or dry silica, colloidal silica, aluminum silicate, titanium dioxide, calcium carbonate, calcium phosphate, barium sulfate, alumina, aluminum hydroxide, boehmite, magnesium hydroxide, magnesium carbonate, zinc carbonate, zinc oxide, antimony oxide, cerium oxide, zirconium oxide, tin oxide, lanthanum oxide, magnesium oxide, barium carbonate, zinc carbonate, basic carbonates, barium sulfate, calcium sulfate, lead sulfate, zinc sulfide, mica, titanium mica, talc, clay, kaolin, lithium fluoride, and calcium fluoride.

[0049] The inorganic particle content is preferably 150 to 1900 parts per 100 parts of polymer. If the inorganic particle content is less than 150 parts, collisions between particles that resist the shrinkage stress when the olefin film shrinks are less likely to occur, which is undesirable. On the other hand, if the inorganic particle content exceeds 1900 parts, the amount of polymer relative to the inorganic particles is too small, so the particles will not be supported and will fall off, resulting in so-called powder shedding, which is undesirable.

[0050] The polymer concentration of the binder liquid is preferably 0.5% by mass or more and 10% by mass or less. If the polymer concentration is less than 0.5% by mass, the amount of polymer is insufficient, which may cause powder shedding and is therefore undesirable. On the other hand, if the polymer concentration is 10% by mass or more, the viscosity of the polymer solution becomes too high, making it difficult to coat to the appropriate thickness, which is also undesirable.

[0051] A hydrophobic additive may be added to the above polymer solution. Known hydrophobic additives such as fluorine-based, organosilicon-based, and olefin-based additives can be used. Of these, fluorine-based additives with high water-repellent effect are preferred. The amount added is preferably 0.5 to 10 weight percent relative to the amount of solvent in the coating solution. If the amount added exceeds 10 weight percent, the solidification rate will decrease significantly, and productivity will deteriorate, which is undesirable. On the other hand, if the amount added is less than 0.5 weight percent, the water-repellent effect will be low, water will penetrate into the coating layer, and the density of the coating layer will decrease, which is undesirable. A preferred amount added is 1 to 9 weight percent, and more preferably 2 to 8 weight percent.

[0052] [Method for preventing fiber yarn formation using polymer solutions, and method for forming films] The polymer solution of the present invention can also be used for fiber spinning and film molding. The spinning and film molding methods can be carried out according to conventionally known methods. For example, dry solidification or wet solidification can be used. In the case of dry solidification, the drying temperature is preferably 80°C to 250°C. More preferably 150°C to 250°C. Below 80°C is undesirable because the drying rate is slow. Above 250°C is undesirable due to the handling of organic solvents.

[0053] Furthermore, in the case of wet coagulation, the liquid composition of the coagulation solution must be that of a poor solvent for the polymer solution. The composition of the coagulation solution does not necessarily have to be monolithic. Although not particularly limited, specific compositions of the coagulation solution in the present invention include, for example, water, alcohol, a mixed solution of water and the solvent of the present invention, or a mixed solution of alcohol and the solvent of the present invention. From the viewpoint of the efficiency of solvent recovery, a mixed solution of water and the solvent of the present invention, or a mixed solution of alcohol and the solvent of the present invention, is preferred.

[0054] The fibrous polymer or film-like polymer formed by solidification may be washed with water to remove residual solvent. While not particularly limited, examples of washable solutions include water, alcohol, a mixed solution of water and the solvent of the present invention, or a mixed solution of alcohol and the solvent of the present invention. From the viewpoint of efficiency in solvent recovery, a mixed solution of water and the solvent of the present invention, or a mixed solution of alcohol and the solvent of the present invention, is preferred. From the viewpoint of efficiency in solvent recovery, a mixed solution of water and the solvent of the present invention, or a mixed solution of alcohol and the solvent of the present invention, is preferred. The water washing bath temperature is preferably 10 to 100°C. Temperatures below 10°C are undesirable because the washing speed decreases. Temperatures above 100°C are undesirable because it is necessary to suppress water evaporation.

[0055] After washing with water, dry at a temperature of 80°C or higher. A drying temperature of 80-200°C is preferable. The dried fibrous polymer or film polymer may be cut or used as is. The fibrous polymer or film polymer after solidification, or the fibrous polymer or film polymer after washing and drying, may be stretched and heat-treated. [Examples]

[0056] The present invention will be described in detail below with reference to examples and comparative examples, but the scope of the present invention is not limited to the following examples and comparative examples. Furthermore, the physical properties in the examples were measured by the following methods.

[0057] (1) Weight average molecular weight (Mw) The molecular weight distribution (weight-average molecular weight (Mw) and molecular weight polydispersity (Mw / Mn), etc.) was measured by gel permeation chromatography (GPC) under the following measurement conditions. Equipment name: High-performance liquid chromatograph LC-20A series (Shimadzu Corporation) Column Oven: CTO-20A Mobile phase: NMP Autosampler: SIL-20AHT LC Workstation: LC Solution Flow rate: 0.3ml / min Differential refractometer detector: RID-10A Oven temperature: 60℃ Molecular weight standard sample: Polystyrene

[0058] (2) Solubility of fibers in solvent The fibers were placed in a solvent and stirred at 120°C for approximately 3 hours using a magnetic stirrer. The transparency and uniformity of the solution were then visually assessed.

[0059] (3) Content of salts containing ions derived from inorganic compounds in the total aromatic polyamide solution A total aromatic polyamide solution was weighed to 1,000 g using a precision scale and placed in a crucible. The total aromatic polyamide solution in the crucible was heated in a vacuum dryer at 100°C for 5 hours, and then heated in an electric furnace at 750°C for 3 hours. The amount of residue in the crucible was measured and this was determined to be the salt content containing ions derived from inorganic compounds.

[0060] <Comparative Example 1> [Polymerization of all aromatic polyamides (copolyparaphenylene, 3,4'-oxydiphenylene, terephthalamide)] 94.0 g of N-methyl-2-pyrrolidone (NMP) with a moisture content of 100 ppm or less, 1.081 g of paraphenylenediamine, and 2.002 g of 3,4'-diaminodiphenyl ether were placed in a reaction vessel at room temperature, dissolved and mixed under a nitrogen atmosphere, and then 4.060 g of terephthalic acid chloride was added while stirring. Subsequently, polymerization was carried out at 60°C to obtain a clear, viscous polymer solution. Next, 6.586 g of a 22.5% calcium hydroxide NMP slurry solution was added, and polymerization was completed by a neutralization reaction to obtain a copolymer of paraphenylene·3,4'-oxydiphenylene·terephthalamide (weight-average molecular weight 590,000) solution.

[0061] [Manufacturing of fully aromatic polyamide (copolyp-phenylene-3,4'-oxydiphenylene-terephthalamide) fibers] A copolymerized p-phenylene·3,4'-oxydiphenylene·terephthalamide (weight-average molecular weight 590,000) solution obtained by polymerization was extruded from a 1000-hole fiber spinning nozzle and spun into an aqueous solution with an NMP concentration of 30 wt% through an air gap of approximately 4 mm, where it was allowed to solidify (semi-dry semi-wet spinning method). After washing and drying, the solution was then stretched 10 times at a temperature of 500°C and wound up to obtain copolymerized p-phenylene·3,4'-oxydiphenylene·terephthalamide fibers with a single filament fineness of 1.67 dtex and 1000 filaments.

[0062] [Dissolution of copolymer paraphenylene·3,4'-oxydiphenylene·terephthalamide fibers] 10.0 g (0.101 mol) of N-methyl-2-pyrrolidone (NMP) was mixed with 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber, cut to a length of 3 mm using a guillotine cutter. The mixture was stirred at 120°C for approximately 3 hours using a magnetic stirrer. The mixture was opaque and the copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber did not dissolve.

[0063] <Comparative Example 2> The procedure was carried out in the same manner as in Comparative Example 1, except that the solvent was changed to dimethyl sulfoxide (DMSO) 10.0 g (0.128 mol). Copolyp-phenylene·3,4'-oxydiphenylene·terephthalamide fibers were added and stirred. The mixture was opaque, and the coplyp-phenylene·3,4'-oxydiphenylene·terephthalamide fibers did not dissolve.

[0064] <Comparative Example 3> The procedure was carried out in the same manner as in Comparative Example 1, except that the solvent was changed to 10.0 g (0.066 mol) of diazabicycloundecene (DBU). Copolyp-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixture was opaque, and the coplyp-phenylene·3,4'-oxydiphenylene·terephthalamide fiber did not dissolve.

[0065] < reference Example 1> In Comparative Example 1, the solvent was changed to a cosolvent obtained by mixing 3.4 g (0.044 mol) of dimethyl sulfoxide (DMSO) and 6.6 g (0.043 mol) of diazabicycloundecene (DBU), comparison The procedure was carried out in the same manner as in Example 1, and 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became clear and homogeneous, and copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0066] Furthermore, 1,000 g of the obtained copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was weighed, placed in a crucible, and heated in an electric furnace at 750°C for 3 hours. The residue in the crucible was weighed to 0.002 g (2000 PPM), confirming that the salt content containing ions derived from inorganic compounds was 10,000 PPM or less.

[0067] < reference Example 2> reference In Example 1, the only difference was that the amount of copolymer paraphenylene·3,4'-oxydiphenylene·terephthalamide fiber was changed to 0.420g. This is for reference. The procedure was carried out in the same manner as in Example 1. The mixed solution became clear and homogeneous, yielding a copolymer of p-phenylene·3,4'-oxydiphenylene·terephthalamide.

[0068] < reference Example 3> reference In Example 1, the solvent was changed to a cosolvent obtained by mixing 1.0 g (0.013 ml) of dimethyl sulfoxide (DMSO) and 9.0 g (0.059 mol) of diazabicycloundecene (DBU), reference Similar to Example 1, copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fibers were added and stirred. The mixed solution became clear and homogeneous, yielding copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution.

[0069] < reference Example 4> reference In Example 1, the solvent was changed to a cosolvent obtained by mixing 5.0 g (0.064 mol) of dimethyl sulfoxide (DMSO) and 5.0 g (0.033 mol) of diazabicycloundecene (DBU), reference The procedure was carried out in the same manner as in Example 1, and 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became clear and homogeneous, and copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0070] < reference Example 5> reference In Example 1, the solvent was N-methyl-2-pyrrolidone (NMP) 4.0 g (0.040 mol). and Except for changing to a cosolvent obtained by mixing in 6.0 g (0.039 mol) of azabicycloundecene (DBU), reference The procedure was carried out in the same manner as in Example 1, and 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became clear and homogeneous, yielding a copolymer of p-phenylene·3,4'-oxydiphenylene·terephthalamide.

[0071] < reference Example 6> reference In Example 1, the solvent was changed to a cosolvent obtained by mixing 3.7 g (0.042 mol) of N,N-dimethylacetamide (DMAc) and 6.3 g (0.041 mol) of diazabicycloundecene (DBU), reference The procedure was carried out in the same manner as in Example 1, and 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became translucent, and copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0072] < reference Example 7> referenceIn Example 1, the solvent was changed to a cosolvent obtained by mixing 3.9 g (0.050 mol) of dimethyl sulfoxide (DMSO) and 6.1 g (0.049 mol) of diazabicyclononene (DBN), reference The procedure was carried out in the same manner as in Example 1, and 0.630 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became clear, and copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0073] <Comparative Example 4> In Example 1, the procedure was carried out in the same manner as in Example 1, except that the solvent was changed to a cosolvent obtained by mixing 1.1 g (0.061 mol) of water (H2O) and 8.9 g (0.058 mol) of diazabicycloundecene (DBU). Then, 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The fiber changed color but did not dissolve.

[0074] <Example 8> In a high-pressure autoclave, water (H2O) and diazabicycloundecene (DBU) were added in molar equivalents and stirred with a stirring blade to obtain a cosolvent. The autoclave was then sealed with 0.5 MPa of carbon dioxide at 25°C and left for 30 minutes. Water, DBU, and carbon dioxide reacted to form a salt. 2.4 g of the salt was mixed with 7.6 g (0.050 mol) of diazabicycloundecene (DBU), and the procedure was carried out in the same manner as in Example 1. 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became clear and homogeneous, and a copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0075] <Example 9> In Example 8, 2.4 g of the salt produced was mixed with 7.6 g (0.098 mol) of dimethyl sulfoxide (DMSO), and the procedure was carried out in the same manner as in Example 1. 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became clear and homogeneous, and a copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0076] <Comparative Example 5> In Example 1, the procedure was carried out in the same manner as in Example 1, except that the solvent was changed to a cosolvent obtained by mixing 0.4 g (0.012 mol) methanol (MeOH) with 1.5 g (0.012 mol) diazabicyclononene (DBN). Then, 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber did not dissolve.

[0077] <Example 10> In Comparative Example 5, a cosolvent was prepared by mixing 0.4 g (0.012 mol) methanol (MeOH) with 1.5 g (0.012 mol) diazabicycloundecene (DBN), and this was bubbling for 1 minute using a carbon dioxide cylinder. The resulting solvent was then prepared in the same manner as in Example 1, and 0.210 g of copolymer-p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became clear and homogeneous, yielding a copolymer-p-phenylene·3,4'-oxydiphenylene·terephthalamide solution.

[0078] <Example 11> In Example 1, the procedure was carried out in the same manner as in Example 1, except that the solvent was changed to an ionic liquid obtained by mixing 2.8 g (0.047 mol) of acetic acid (AcOH) with 7.2 g (0.047 mol) of diazabicycloundecene (DBU). Then, 0.600 g of copolymer-p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became transparent and homogeneous, and a copolymer-p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0079] <Example 12> In Example 1, the procedure was carried out in the same manner as in Example 1, except that the solvent was changed to a solvent obtained by mixing 0.7 g (0.012 mol) of acetic acid (AcOH) with 9.3 g (0.061 mol) of diazabicycloundecene (DBU). Then, 0.600 g of copolymer-p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became transparent and homogeneous, and a copolymer-p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0080] <Example 13> In Example 1, the procedure was carried out in the same manner as in Example 1, except that the solvent was changed to a solvent obtained by mixing 1.2 g (0.020 mol) of acetic acid (AcOH) and 2.5 g (0.020 mol) of diazabicycloundecene (DBN). Then, 0.210 g of copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was added and stirred. The mixed solution became transparent and homogeneous, and a copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide solution was obtained.

[0081] < reference Example 14> [Production of fully aromatic polyamides (polymetaphenylene isophthalamides)] Metaphenylenediamine and isophthalic acid chloride were polymerized by a known method (interfacial polymerization, Japanese Patent Publication No. 47-10863) to obtain polymetaphenylene isophthalamide powder (weight-average molecular weight 700,000).

[0082] [Dissolution of polymetaphenylene isophthalamide] In Example 1, the procedure was carried out in the same manner as in Example 1, except that the copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was replaced with polymetaphenylene isophthalamide powder. 1,100 g of polymetaphenylene isophthalamide powder was added and stirred. The mixed solution became transparent and homogeneous, yielding a polymetaphenylene isophthalamide solution.

[0083] < reference Example 15> [Production of fully aromatic polyamides (copolyparaphenylene, 4,4'-oxydiphenylene, terephthalamide)] 94.0 g of N-methyl-2-pyrrolidone (NMP) with a moisture content of 100 ppm or less, 1.081 g of paraphenylenediamine, and 2.002 g of 4,4'-diaminodiphenyl ether were placed in a reaction vessel at room temperature, dissolved and mixed under a nitrogen atmosphere, and then 4.060 g of terephthalic acid chloride was added while stirring. Subsequently, polymerization was carried out at 60°C to obtain a clear, viscous polymer solution. Next, 6.586 g of a 22.5% calcium hydroxide NMP slurry solution was added, and polymerization was completed by a neutralization reaction to obtain a copolymer of paraphenylene·4,4'-oxydiphenylene·terephthalamide (weight-average molecular weight 230,000). The obtained copolymer of paraphenylene·4,4'-oxydiphenylene·terephthalamide was coagulated into granules in an aqueous solution of 30 wt% NMP. The powder was washed three times with water after coagulation to obtain copolymer p-phenylene·4,4'-oxydiphenylene·terephthalamide powder.

[0084] [Dissolution of all aromatic polyamides (copolyparaphenylene, 4,4'-oxydiphenylene, terephthalamide)] In Example 1, the procedure was carried out in the same manner as in Example 1, except that the copolymer p-phenylene·3,4'-oxydiphenylene·terephthalamide fiber was replaced with copolymer p-phenylene·4,4'-oxydiphenylene·terephthalamide powder. 0.210 g of copolymer p-phenylene·4,4'-oxydiphenylene·terephthalamide powder was added and stirred. The mixed solution became transparent and homogeneous, yielding a copolymer p-phenylene·4,4'-oxydiphenylene·terephthalamide solution. The results above are summarized in Table 1.

[0085] [Table 1-1]

[0086] [Table 1-2] [Industrial applicability]

[0087] According to the present invention, a fully aromatic polyamide solution can be provided without using inorganic salts, organic salts, etc., in combination with an aprotic organic polar solvent, thus simplifying recovery steps such as extraction with a halogen-based solvent and distillation of the halogen-based solvent.

Claims

1. A fully aromatic polyamide solution comprising a fully aromatic polyamide and at least one of the solvents described in any of (a) to (b) below, characterized in that the content of a salt containing ions derived from an inorganic compound contained in the fully aromatic polyamide solution is 10,000 PPM or less. (a) Salts synthesized from organic strong bases and protic solvents (b) Ionic liquids synthesized from organic strong bases and protic solvents

2. Claim 1 (a) Salts synthesized from organic strong bases and protic solvents (b) Ionic liquids synthesized from organic strong bases and protic solvents The all-aromatic polyamide solution according to claim 1, further comprising an aprotic organic solvent.

3. The all-aromatic polyamide solution according to claim 1, wherein the all-aromatic polyamide solution contains a eutectic mixture.

4. A method for producing all aromatic polyamide fibers, characterized by using the all aromatic polyamide solution described in Claim 1 as a dope for wet spinning.

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