JPH04194023A - Production of polyterephthalic acid dihydrazide fiber and film - Google Patents

Abstract

PURPOSE:To obtain the subject high-performance fiber and film of high practicality at a low cost by dissolving polyterephthalic acid dihydrazide in a solution of ammonium hydroxide, and then processing the resultant solution in an acidic coagulation bath. CONSTITUTION:(B) Polyterephthalic acid dihydrazide having preferably 0.5-8 dl/g intrinsic viscosity in an amount of 5-40wt.% is dissolved in (A) a solution of a quaternary ammonium hydroxide expressed by the formula (R is alkyl, etc.) at 5-40wt.% concentration, and the resultant solution is treated in an acidic coagulation bath, e.g. 0.5-1.0N aqueous solution of phosphoric acid to afford the objective fiber and film.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for producing polyterephthalic acid dihydrazide fibers and films, and more specifically, to a method for producing polyterephthalic acid dihydrazide fibers and films, and more specifically, to a method for producing polyterephthalic acid dihydrazide fibers and films, and more specifically, a method for producing polyterephthalic acid dihydrazide fibers and films, and more specifically, a method for producing polyterephthalic acid dihydrazide fibers and films, and more specifically, a method for producing polyterephthalic acid dihydrazide fibers and films, and more specifically, a method for producing polyterephthalic acid dihydrazide fibers and films, and more specifically, a method for producing polyterephthalic acid dihydrazide fibers and films. Relating to a method of manufacturing.

(Prior art) Polyterephthalic acid dihydrazide is a type of polyamide, and is a polymer with excellent chemical resistance and heat resistance. It can be made into a lyotropic liquid crystal polymer solution, so it has excellent mechanical properties such as strength and elastic modulus. It is a useful polymer that can be processed into fibers or films with excellent properties.

This polyterephthalic acid dihydrazide is obtained by polymerizing terephthalic acid dihydrazide and terephthalic acid dichloride, but since terephthalic acid dihydrazide is a solid that is sparingly soluble in organic solvents, and the polymer produced from it is also sparingly soluble. The reaction did not proceed smoothly and it was difficult to obtain a polymer with a high degree of polymerization.

For this reason, a conventional low-temperature solution polymerization method that uses an amide solvent and adds a third component such as an inorganic salt of a metal such as lithium chloride has been used to remove by-product hydrogen chloride and the third component metal salt after polymerization by washing with water. A polymer that can be used for practical purposes was obtained by removing the polymer and molding it by isolation.

However, the polymer obtained by this method has low affinity for solvents and extremely poor solubility.
It has the disadvantage of being substantially insoluble in general organic solvents including amide solvents.

(Problem to be Solved by the Invention) To solve this problem, an aqueous solution of an organic base selected from tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, pyrrolidine, tert-butylamine, and triethylamine, The use as a processing solvent for polyterephthalic acid dihydrazide is described in Japanese Patent Publication No. 59-22744.

However, tetramethylammonium hydroxide etc.
Tetraalkylammonium halide is usually synthesized by reacting the corresponding trialkylamine with an alkyl halide, and then the halide is then electrodialyzed. Therefore, it is expensive, impractical, and is produced in small amounts. Contamination with halogens and heavy metals associated with electrode reactions is unavoidable and becomes a major problem when producing high-performance polymer molded products. Furthermore, when tetraalkylammonium is used as a solvent and then disposed of, it has poor decomposition efficiency by the conventional activated sludge method, which poses a major obstacle in commercial implementation that requires a solution.

Therefore, an object of the present invention is to provide a method for producing a polymer molded article of polyterephthalic acid dihydrazide using a processing solvent that is highly practical and has excellent solvent performance.

(Means for Solving the Problems) According to the present invention, the following general formula, [Rs NCH2CH2OHI+. A processing solution is prepared by dissolving polyterephthalic acid dihydrazide in a solution containing quaternary ammonium hydroxide represented by A method for producing polyterephthalic acid dihydrazide fibers and films is provided, which comprises forming a membrane.

(Function) The quaternary ammonium hydroxide represented by the above general formula (1) has a specific affinity higher than that of the organic base used as a solvent for polyterephthalic acid dihydrazide. The above-mentioned problems can be solved by dissolving polyterephthalic acid dihydrazide and then spinning or forming a film.

(Preferred embodiment of the invention) The present invention will be explained in detail below.

Synthesis of polyterephthalic acid dihydrazide The polyterephthalic acid dihydrazide used in the present invention is disclosed in U.S. Pat.
and 3,536,651. In this method, terephthalic acid dihydrazide is reacted with terephthalic acid dichloride in a cold organic polar solvent. As an organic polar solvent, hexamethylene phosphoramide (HMPA
), N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAC), dimethylsulfoxide (
DMSO), N,N-dimethylformamide (DMF)
,N.

N, N', N'-tetramethylurea (TMU), etc.
Alternatively, a mixture thereof can be mentioned. Especially H
MPA%NMP%DMAC or a mixture thereof can be preferably used.

Low temperature solution polymerization is accomplished by preparing a homogeneous solution of lithium chloride and terephthalic acid dihydrazide, which is added to improve the solubility of terephthalic acid dihydrazide in such organic polar solvents. Terephthalic acid dichloride is added to this solution, usually with stirring and cooling. The reaction mixture gels within minutes to hours. In some cases, it may be desirable to stir or stand the reaction mixture for 30 minutes to several hours or more.

The polymer can be separated by stirring the reaction mixture in a suitable mixer with a non-solvent for the polymer, such as water.

After the polymer is collected and dried, it is either stored or subsequently processed into a dope.

Quaternary ammonium hydroxide In the present invention, a solution, especially an aqueous solution, containing the quaternary ammonium hydroxide represented by the general formula (1) is used to prepare a processing solution for producing fibers or films.

In this general formula, the group R is an alkyl group such as a methyl group, an ethyl group, a propyl group, or an aralkyl group such as a benzyl group, preferably an alkyl group, and most preferably a methyl group. The quaternary ammonium pyroxide in which all three R's are methyl groups, ie, trimethyl (2-hydroxyethyl) ammonium hydroxide, is known as so-called choline.

The aqueous solution of quaternary ammonium hydroxide represented by the general formula (1) can be obtained with high purity using ethylene oxide, the corresponding tertiary amine, and pure water as raw materials.

When reacting tertiary amine and ethylene oxide with pure water, there is a method in which the tertiary amine gas and ethylene oxide gas are injected into pure water and reacted. Examples include a method of causing a reaction by blowing gas into the solution, and a method of dissolving a tertiary amine gas in pure water and then dropping liquid ethylene oxide to cause a reaction.

As the tertiary amine, trimethylamine, triethylamine, tripropylamine, and tribenzylamine are used.The reaction molar ratio of trialkylamine and ethylene oxide is 0.5 to 1.2 moles of ethylene oxide to 1 mole of trialkylamine. and preferably 0.9 ethylene oxide per mole of trialkylamine.
~1.0 mol.

The reaction is carried out with stirring and cooling. After the reaction, excess trialkylamine is removed under reduced pressure. Thereby, an aqueous trialkyl(2-hydroxyethyl)ammonium hydroxide solution that can be used in the present invention can be obtained.

The synthesized quaternary ammonium hydroxide aqueous solution can be used as it is or with its concentration reduced as required.

In the present invention, a particularly suitable quaternary ammonium hydroxide aqueous solution is a choline aqueous solution. This aqueous solution is particularly suitable because it exhibits high solvency and is able to maintain anisotropy at high temperatures, thus offering great flexibility in the production of molded articles.

For example, a 20% by weight cosine aqueous solution was mixed with 15% of polyterephthalic acid dihydrazide (intrinsic viscosity: ηlnh -7,2).
A solution of weight percent polymer loses its anisotropy and becomes isotropic in the transition temperature range of 50-57°C.

Preparation of processing solution (dope) Polyterephthalic acid dihydrazide prepared according to the above method and quaternary ammonium hydroxide solution prepared to the desired concentration are mixed to obtain a stable, low viscosity and concentration suitable for manufacturing molded products. A range of processing solutions (dopes) can be obtained.

Furthermore, in the presence of polyterephthalic acid dihydrazide prepared according to the above method, quaternary ammonium hydroxide can be synthesized and used as a processing solution (dope). That is, the corresponding tertiary amine and ethylene oxide are dissolved in a suspension of polyterephthalic acid dihydrazide and water to prepare the desired concentration. An aqueous solution of quaternary ammonium hydroxide can be obtained.

When preparing the novel processing solution of the present invention, the intrinsic viscosity of the polyterephthalic acid dihydrazide is at least o, s dl
/g, preferably in the range 1 to 8 dl/g, and the concentration is preferably in the range 5 to 24% by weight, especially 10 to 20% by weight.

The concentration of quaternary ammonium hydroxide in the solvent is preferably in the range of 5 to 40% by weight, particularly 10 to 30% by weight.

The dope consisting of polyterephthalic acid dihydrazide and quaternary ammonium hydroxide has a very low viscosity.

In the present invention, when the dope-forming components are combined in a specific concentration range, the dope has optical anisotropy. That is, the microscopic area of a given dope (
a+1 croscopic region) has birefringence. Qualitative measurements of optical anisotropy in dopes are conveniently made using a light source analyzer and crossed polarizers. Commercially available polarized light microscopes are useful for qualitative measurements of optical anisotropy. Another qualitative measurement method for optical anisotropy can be done visually.

Many anisotropic dopes, when viewed as a whole in a transparent container, appear turbid or cloudy but contain virtually no undissolved matter.

When viewed under normal reflected light and disturbed by tilting or rotating the container, or by gradual moderate agitation, anisotropy is characteristically easily noted. It produces a bright shine or luster, which slowly decreases in intensity after the disturbance is stopped. In some anisotropic dopes no color occurs, while in others they have a bluish color or some mixed color, the latter color being described by the observer as pearly or opalescent. It is described as having a different color.

The anisotropic dope disturbed as described above often appears to have stripes or grains on its surface. All of these visual effects are believed to be due to the birefringence or anisotropy of at least a portion of the anisotropic doping and the non-uniform arrangement of the large number of small aligned regions.

Optically anisotropic aqueous solutions are generally obtained only within certain limits of polymer concentration, intrinsic viscosity, solvent composition, and temperature. As an example of the correlation, FIG. 1 shows the correlation of doping polyterephthalic acid dihydrazide (ηInh = 6.4) in an aqueous choline solution (measurement temperature: 25° C.). As is clear from this Figure 1, the concentration of choline aqueous solution is 42
It can be seen that polyterephthalic acid dihydrazide hardly dissolves when the amount exceeds % by weight. Such relationships for other dopes can also be easily determined by routine repeated experimentation.

The processing solution described above can be extruded into fibers or films by conventional wet methods. In the wet spinning method, spinning can be performed at room temperature. A suitably prepared dope containing the polymer is placed in a suitable coagulation bath, e.g. a dilute aqueous phosphoric acid solution (0.5-1.ON) kept at 20°C, depending on the solvent used to make the dope. extrude Other useful coagulants include, for example, dilute acetic acid (0.5 to 1.0
N), sulfuric acid (0.5-1.ON), methanol/hydrochloric acid (10/1, volume/volume).

In the wet spinning method, when the quaternary ammonium hydroxide aqueous solution used for dope production contains a large amount of metal ions, polyterephthalic acid dihydrazide forms a metal chelate polymer and precipitates in the dope. This makes it difficult to extrude the dope from the spinneret. That is, it is desired that the quaternary ammonium hydroxide aqueous solution used for dope preparation contains an extremely small amount of metal ions.

After forming, the fibers can be passed over finishing rolls and wound onto bobbins. For the best fiber and yarn properties, the bobbin can be soaked in water or a mixture of water and a water-soluble inert organic solvent (e.g., acetone, ethyl alcohol, glycerin) to remove any remaining quaternaries. This can be aided by removing the ammonium hydroxide and salt or acid and then drying. Removal of residual solvents and salts can be accomplished by passing the fiber or yarn through an aqueous solution during the process or by spraying the bobbin with water during yarn formation.

The dope prepared according to the present invention has a wide optical anisotropy region and low viscosity in the optical anisotropy region, making it easy to extrude from a spinneret.

(Example) In the examples, measurements and tests were performed by the following methods.

intrinsic viscosity Intrinsic viscosity (ηlnh) is defined by the following formula.

In the formula, ηrsl is the specific viscosity, and C is the specific viscosity η, which represents the polymer concentration of 0 and 5 g in 100 ml of solvent, respectively.
rsl was determined by measuring the viscosity of a dilute polymer solution and pure solvent using a B-type viscometer, and dividing the viscosity of the dilute polymer solution by the viscosity of the pure solvent.

The dilute solution used here for the determination of ηrs+ was of the concentration expressed by C above, and the viscosity was measured at 20° C. using a 5% by weight aqueous diethylamine solution as the solvent.

Preparation of dope viscosity The viscosity of the dope prepared by a prescribed method was measured at 25° C. using a B-type viscometer.

Fiber properties such as strength, elongation, and initial modulus are T/E/
M, and were recorded in their customary units: grams per denier, percent, and grams per denier. Denier is abbreviated as Den. 1a fiber samples are not refined, but generally unless otherwise specified,
Conditioned for at least 16 hours at 20° C. and 65% relative humidity.

Light 1" (mulled) Optical anisotropy was measured visually.

Example 1 Synthesis of polyterephthalic acid dihydrazide 101.96 g of terephthalic acid dihydrazide (0,52
N,N-
It was dissolved in 3000 ml of dimethylacetamide (DMAC). After dissolving lithium chloride and terephthalic acid dihydrazide, the homogeneous solution is cooled to 10t. Terephthalic acid dichlorite 1oδ, 59 g (0,525 mol) was added in one portion under stirring. After stirring for 30 minutes, stop stirring,
The reaction mixture was left at autogenous temperature for 3 hours. The opaque gelatinous reaction mixture was transferred into 7jZ pure water to precipitate the product, which was further washed three times with 71 pure water and once with 71 methanol. After washing, the product is dried in an air dryer for 2
It was dried for 4 hours and further dried at 100°C in a vacuum dryer. 167.6 g of polyterephthalic acid dihydrazide (η
Inh = 7.0) was obtained.

Total of choline aqueous solution 30.3% by weight trimethylamine aqueous solution 216.6 g
(1.11 mol) was charged into a 500 ml stainless steel flask equipped with a stirrer, a nitrogen inlet, and an ethylene oxide dripping port. After replacing the inside of the flask with nitrogen, 45.0 g (1.02 mol) of liquid ethylene oxide
The mixture was added dropwise over 2 hours while maintaining the temperature at 10°C. After completing the dropwise addition of ethylene oxide, the reaction solution was stirred at 10° C. for 1 hour.

Vacuum was applied to a pot temperature of 30-35° C. and excess trimethylamine was distilled off at approximately 20-25 mm Hg for 1 hour.

Yield of choline aqueous solution is 254.0 g, concentration is 48.0
%Met. Iron, sodium, and chloride in this aqueous solution are 201) Ilb or less, 201) Ilb or less, respectively.
It was 1.0 ppm or less.

Preparation of processing solution and fiber 10.0 g of polyterephthalic acid dihydrazide prepared above was mixed with 61.9 g of pure water and 28.1 g of 48°
15% by weight prepared by mixing choline aqueous solution
An optically anisotropic spinning dope containing 10% by weight of polymer was prepared by combining with an aqueous choline solution.

After removing any undissolved particles in the usual manner, the dope was passed through a 0.6 mm thick stainless steel spinneret having 20 holes with a hole diameter of 0.1 mm at a pressure of 0.2 mm. It was extruded at a rate of about 1.40 ml/min at Kg/c+n2 into a coagulation bath (length 60 cm) consisting of 350 g of phosphoric acid and 7 Il of pure water maintained at 20°C. The fibrils were drawn through the bath at a speed of 8.79 m 7 min.
．． It was collected on a bobbin at a speed of 30 m/min. Next, while the discharged filament was wound up on a bobbin, the water was changed until the pure water no longer showed acidity, and the extruded filament was immersed in pure water. Thereafter, it was air-dried while being wound on a bobbin. T/E/M i of dry filament
/ Den, value is 7.9/6.4 /224 /6
．． It was 99.

This example demonstrates the production of practical polyterephthalic acid dihydrazide fibers from an optically anisotropic dope of the polymer in a 15% by weight aqueous choline solution.

Example 2 Preparation of processing solution and fiber Polyterephthalic acid dihydrazide 15 prepared in Example 1
．． 25.0% by weight prepared by mixing 0g with 40.7g of pure water and 44.3g of 48.0% by weight choline aqueous solution
By combining with choline aqueous solution, 15.0% by weight
An optically anisotropic spinning dope containing a polymer of

After removing a small amount of undissolved particles in a conventional manner, the dope was passed through a 0.6 non-thick stainless steel spinneret having 20 holes with a hole diameter of 0.1 mm at a pressure of 0.8 mm. It was extruded at a rate of approximately 0.85 m1/min at Kg/cm2 into a coagulation bath (length 60 cm) consisting of 350 g of phosphoric acid and pure water at 7°C maintained at 20°C. The fibrils were drawn through the bath at a speed of 6.28 m/min and 7.54 m/min.
was collected on a bobbin at a speed of 1/min. Next, while the discharged filament was wound up on a bobbin, the water was changed until the pure water no longer showed acidity, and the extruded filament was immersed in pure water. Thereafter, it was air-dried while being wound on a bobbin. T/E/Mr/D of dry filament
An, I Nao is 6.915.9/172 /12.
It was 84.

This example demonstrates the production of practical polyterephthalic acid dihydrazide fibers from an optically anisotropic dope of the polymer in a 25 weight percent aqueous choline solution.

Example 3 Preparation of dope and measurement of viscosity 180.0 g of a 15.0% by weight aqueous choline solution and 20.0 g of polyterephthalic acid dihydrazide (ηlnh =
7-2), an optically anisotropic tope containing 10.0% by weight of the polymer was prepared. While maintaining this dope at 25° C. for 17 days, the viscosity of the dope was measured at 25° C. using a B-type viscometer at 1 day, 2 days, 11 days, 17 days, etc. after preparation. The results of measuring the viscosity of the dope are shown in FIG.

In this example, the viscosity change of the dope obtained from the choline aqueous solution and polyterephthalic acid dihydrazide was measured, and it was proved that the dope prepared from the purine aqueous solution and polyterephthalic acid dihydrazide was stable.

Examples 4 to 6 Preparation of Tope and Measurement of Viscosity Change An aqueous choline solution and polyterephthalic acid dihydrazide were prepared according to the method of the present invention, and the viscosity of the tope at 25°C was measured using a B-type viscometer. The measurement results are shown in Table 1.

This example proves that the viscosity of the dope prepared from the aqueous choline solution and polyterephthalic acid dihydrazide is low.

Example 7 Preparation of processing solutions and fibers Polyterephthalic acid dihydrazide (ηlnh = 7-2)
10.0g to 90.0g of 15% by weight triethyl (2-
An optically anisotropic spinning dope containing 10.0% by weight of polymer was prepared by combining with an aqueous solution of hydroxyethyl) ammonium hydroxide. After removing a few undissolved particles in the usual manner, the dope was passed through a stainless steel spinneret 0.6 mm thick with 20 holes with a hole diameter of 0.08 mm at a pressure of 0.68 g7 cm2. 20 at a speed of approximately 0.67 m1/min.
It was extruded into a coagulation bath (length 60 cm) consisting of 350 g of phosphoric acid and 71 g of pure water maintained at .degree. 8. drawing the fibrils through the bath at a speed of 7.54 m/min; '79m/
It was collected on a bobbin at a speed of 1 minute. Next, while the discharged filament was wound up on a bobbin, the water was changed until the pure water no longer showed acidity, and the extruded filament was immersed in pure water.

Thereafter, it was air-dried while being wound on a bobbin. The T/E/Ml/Den values of the dried filament were 10.1/6.2/224/4.77.

The production of highly practical polyterephthalic acid dihydrazide fibers was also demonstrated using an optically anisotropic dope in which an aqueous solution of triethyl (2-hydroxyethyl) ammonium ohitroxide was used in place of the aqueous solution of choline in Example 1. Ta.

Comparative Example 1 Measurement of optically anisotropic region Polyterephthalic acid dihydrazide in tetramethylammonium hydroxide aqueous solution (ηinh = 7-2
) (measurement temperature: 25°C) is shown in Figure 3.

It can be seen from FIG. 3 that when the concentration of the tetramethylammonium hydroxide aqueous solution becomes 25% by weight or more, polyterephthalic acid dihydrazide hardly dissolves.

This relationship can be easily determined by a conventional rippling experiment.

This comparative example illustrates the optically anisotropic region of the dope obtained from an aqueous solution of tetramethylammonium hydroxide and polyterephthalic acid dihydrazide, and by comparing this with FIG. It can be seen that the dope prepared from dihydrazide has a wide optically anisotropic region.

Comparative Examples 2 to 4 Preparation of Dope and Measurement of Viscosity Tetramethylammonium hydroxide aqueous solution and polyterephthalic acid dihydrazide were prepared according to the method of the present invention, and the viscosity of the dope at 25°C was measured using a B-type viscometer. The measured values are shown in Table 2.

This comparative example illustrates the viscosity of a dope prepared from an aqueous solution of tetramethylammonium hydroxide and polyterephthalic acid dihydrazide, and the viscosity of a dope prepared from an aqueous solution of choline and polyterephthalic acid dihydrazide by comparison with Examples 4-6. is found to be low.

Comparative Example 5 Preparation of dope and measurement of viscosity change = 180.0 g of an aqueous solution of tetramethylammonium hydroxide having an OJi amount of 15%, and 10% by weight of polyterephthalic acid dihydrazide (η1□ゎ=7.2) from 20.0 g An optically anisotropic dope containing % of polymer is prepared. While maintaining this dope at 25°C for 17 days, 1 day, 2 days, and 11 days after dope preparation,
After 17 days, the viscosity of the dope was measured using a B-type viscometer.

Figure 2 shows the results of measuring the viscosity of the dope.

This comparative example illustrates the viscosity change of the dope prepared from the tetramethylammonium hydroxide aqueous solution and polyterephthalic acid dihydrazide, and the comparison with Example 3 shows that the dope prepared from the choline aqueous solution and polyterephthalic acid dihydrazide is stable. I understand that.

(Effects of the Invention) According to the present invention, when spinning or forming a film from polyterephthalic acid dihydrazide, by using a solution containing the compound represented by the general formula (1), it is possible to achieve high practicality and improved solvent performance. A method for producing a polymer molded article of polyterephthalic acid dihydrazide using an excellent processing solvent is provided. Furthermore, the polymer molded articles obtained according to the present invention have high performance.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the correlation of the dope of polyterephthalic acid dihydrazide (ηlnh "8-4) in a choline aqueous solution. FIG. 2 is a diagram showing the measurement results of the viscosity of the dope. The figure shows polyterephthalic acid dihydrazide (ηlnh) in an aqueous solution of tetramethylammonium hydroxide.
=7.2). Procedural Amendment (Mutsu) December 14, 1990 Mr. Satoshi Uematsu, Commissioner of the Japan Patent Office 2. Title of the invention: Process for producing polyterephthalic acid dihydrazide fibers and films 3. Relationship with the case by the person making the amendment Address of the patent applicant 2-1-1 Uchisaiwai-cho, Chiyoda-ku, Tokyo Name: Nippon Hydrazine Kogyo Co., Ltd. 4, Agent: 105 Telephone: (436) 3527 5, No date for amendment order 6, Subject of amendment 7 Statement of Contents of Amendment Page 16 In the 6th line from the bottom, the phrase ``Adjustment of viscosity of dope'' should be corrected to ``Measurement of viscosity of dope J.''

Claims (4)

[Claims] (1) Quaternary ammonium represented by the following general formula, [R_3NCH_2CH_2OH]^+・OH^- (in the formula, R represents an alkyl group or an aralkyl group, and the three Rs may be the same or different) A polyterephthalic acid dihydrazide fiber characterized in that a processing solution is prepared by dissolving polyterephthalic acid dihydrazide in a solution containing hydroxide, and spinning or film formation is performed by treating this processing solution with an acidic coagulation bath. Film manufacturing method. (2) The manufacturing method according to claim 1, wherein the solution containing quaternary ammonium hydroxide is an aqueous solution. (3) The manufacturing method according to claim 1, wherein the processing solution is prepared by dissolving a tertiary amine corresponding to the quaternary ammonium hydroxide and ethylene oxide in an aqueous suspension of polyterephthalic acid dihydrazide. . (4) Polyterephthalic acid characterized by neutralizing hydrochloric acid from the polymerization process of polyterephthalic acid dihydrazide with choline from the spinning or membrane forming process of polyterephthalic acid dihydrazide, and separating the resulting organic base choline chloride. Method for producing dihydrazide fibers or films.