JPH02269738A - Production of copolyamideamic acid and copolyamideimide fiber - Google Patents

Abstract

PURPOSE:To produce a copolyamideamic acid which can give a copolyamideimide molding which can exhibit excellent heat resistance and mechanical properties by a simple process by using a specified acid component and a specified diamine component in a specified compositional ratio. CONSTITUTION:This copolyamideamic acid is composed of structural units I of formula I and/or II (wherein R is H or a 1-4C alkyl) and structural units II of formula III and structural units III of formula IV (wherein X is a 1-2C alkyl or alkoxy; and n is an integer of 1-2). The molar ratio among the structural units are such that the sum of I and II may be substantially equal to III and the ratio (r) of I to II may satisfy the equation: r=95/5-10/90. In forming a copolyamideimide fiber by spinning a molding dope mainly consisting of the above copolyamideamic acid, this dope is first discharged into an inert atmosphere and then led to an aqueous coagulation bath. Thus, a copolyamide fiber having a high modulus, a high strength and a suitable elongation can be obtained.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a copolyamide amic acid that provides a polyamideimide useful in the aerospace field or the electronic materials field, and a fiber that is thermally and mechanically crushed from the copolyamide amic acid. The present invention relates to a method for producing copolyamide-imide fibers. (Prior art) Polyamide-imide and polyimide have been known to be useful as raw materials for fibers, films, and other molded products with excellent heat resistance, mechanical properties, electrical properties, and weather resistance. Polyimide produced from 4,4'-diaminodiphenyl ether and pyromellitic dianhydride provides a film with excellent heat resistance, and is widely used for electrical insulation purposes. In addition, in the field of heat-resistant fibers and films, aramid and polyamide-imide fibers, synthetic papers, polyimide films, etc. are being used, and advanced materials for space and aircraft applications are becoming more highly heat-resistant. In recent years, there has been a demand for materials with mechanical properties such as high strength, high strength, and high modulus. Therefore, in order to improve the mechanical properties of polyimide, which has excellent heat resistance, the importance of rigid skeleton polyimide is being recognized. By the way, as polyimide is often insoluble and infusible, the general manufacturing method for polyimide is to dry or wet mold a molding dope made of polyamic acid, which is its precursor, and to ring-close the polyamic acid during the molding process. A method of obtaining a polyimide molded body is adopted. At this time, there are the following problems. 1. Poly-p-phenylene (or 4.4°-biphenylene) pyromellitimide, which forms a completely rigid skeleton, undergoes heat treatment in order to rapidly crystallize during the imidization process due to its rigidity. It has poor stretchability, and as a result, does not exhibit advanced mechanical properties.Furthermore, due to the low mobility of molecular chains, internal stress increases during the imidization and accompanying crystallization process, resulting in cracks during film production.・Cracks occur. 2. Polyamic acid, which is a precursor of polyimide, generally has poor coagulation properties during wet molding, which is a major factor that hinders the development of physical properties. To give an example regarding 1, the Journal of the Japan Textile Science Society Vol 140, N
As described in G12, T-480 to T-487, poly-4,4°-biphenylene pyromellitimide has an initial elastic modulus of 1,000 or more and a strength of 10 g/de or more. It is widely known that m-fibers with high elastic modulus and high strength cannot be obtained, and at the same time, only brittle films that are practically unusable can be obtained from such polyimides. In consideration of the above problems, various polyimides have been proposed that exhibit good mechanical properties by reducing crystallinity and improving formability without extremely reducing the openness of molecular chains. For example, JP-A-60-97834, JP-A-62-
No. 77921, JP-A-62-117815, etc. disclose copolyimides in which a monomer having a bent chain is partially copolymerized with an acid component or a diamine component constituting the polyimide. Although high-strength molded bodies can certainly be obtained from these copolyimides, it is difficult to achieve a high modulus of elasticity due to the four-fold fabric of the bent chains. Further, all of the copolyimide precursors have poor coagulability. Also, JP-A-61-188127, JP-A-62-
According to Publication No. 79227 and the like, a copolypyromellitimide is disclosed in which two or more kinds of rigid diamines are used, and at least one of them is a nuclear chlorine-substituted rigid diamine. These can achieve a higher modulus of elasticity than those described above. However, the nuclear chlorine-substituted rigid diamine, which is an essential component, has poor reactivity, and as a result, it is not possible to obtain a polyimide with a high degree of polymerization, leaving problems in fatigue resistance and the like. In addition, these diamines are generally expensive;
It is difficult to provide inexpensive materials that are advantageous for industrial use. Furthermore, the above polyimide contains chlorine,
Has Zhao during the environmental pollution when burning and selling. Note that these copolyimide precursors also have poor coagulability. Incidentally, polyimide having a rigid skeleton is attracting attention from the viewpoint of low thermal expansion even in insulation coating applications in the semiconductor field, and various polyimides have been proposed. For example, JP-A-62-253621 discloses a polyimide using a rigid diamine. but,
According to this publication, as a more preferred embodiment, acid component 6.
．． It is specified that 25 mol% or more of 3,3", 4,4'-biphenyltetracarboxylic acid (derivative) should be used, and this composition has poor wet moldability (no mention is made of coagulation during wet molding). ), and there is no mention of mechanical properties at all.
191830 also proposes a copolyimide comprising a rigid diamine of 3.3°-dimethylbenzidine and a p-phenylenediamine derivative, but the composition of the precursor of this copolyimide still has poor coagulability. As mentioned above, it can be said that all of the above polyimides have not improved the problem 2 at all, that is, they do not exhibit good coagulation properties in an aqueous coagulation system, which is the easiest to handle. In order to improve problem 2, the following method has been proposed. That is, according to JP-A No. 60-65112, a soluble polyimide containing 3,3°, 4,4'-biphenyltetracarboxylic acid (derivative) as the main component is used as the acid component.
A method of coagulating a molding solution comprising the polyimide is disclosed. Although this molding solution exhibits good coagulation properties, an alcoholic solution such as methanol is used as the coagulation bath, and it lacks the ease of mounting. Furthermore, since the polyimide is mainly composed of the above-mentioned acid component, it also has the problem that a high modulus of elasticity cannot be achieved. Further, according to Japanese Patent Application Laid-open No. 59-157319, a method has been proposed in which polyamic acid is partially imidized with acetic anhydride or the like to improve its coagulability. This method is applicable to almost all polyamic acids, but since the molding solution is a multi-component system and imidization progresses over time, it is difficult to control the molding solution in a uniform molding solution. This includes the problem that it cannot be provided stably. In view of this, the present inventors previously filed a patent application in
No. 6344, amines and/or p were added to the molding solution.
We propose a method of improving the coagulation properties of the solution by adding a metal salt of an acid with a Ka of 4.3 or higher. Although this method can provide a stable solution that does not change over time,
After all, it will be a molding solution or a multi-component system. As described above, it can be said that there is still no polyamic acid that can simultaneously solve the above two problems and provide a polyimide molded article with excellent mechanical properties through a simple process. By the way, the inventor of this application previously filed Japanese Patent Application No. 63-87312.
In Japanese Patent Application No. 1987-87313, a method for producing a high elastic modulus fiber of homopolyimide consisting of pyromellitic acid (derivative) and rigid diamine was described. A new homopolyimide and fiber made of °-dimethylbenzidine and a method for producing the same were proposed. At this time, it was found that polyamic acids using 3,3'-dimethylbenzidine, 3,3'-dimethoxybenzidine and 2,2'-dimethylbenzidine as diamine components exhibit good coagulation properties in aqueous coagulation. In addition, the polyimide fiber obtained from the polyamic acid exhibits excellent mechanical properties. However, since the polyimide is a homopolymer, it is highly crystalline, and as a result, its elongation is somewhat insufficient, making it easy to break and making it difficult to handle. This left a problem. (Object of the Invention) The object of the present invention is to solve the above-mentioned problems and provide a new copolyamide molded product that exhibits excellent heat resistance and R mechanical properties by a simple process. Amic acid, and high elastic modulus from the copolyamide amic acid,
The object of the present invention is to provide a method for producing copolyamide-imide fibers having high strength and appropriate elongation. (Structure of the Invention) In order to achieve the above object, the present inventors conducted extensive research on both the chemical structure of polyimide and the spinning conditions, and as a result, from a copolyamide amic acid having a specific chemical structure,
Although it is a copolymer, it is possible to obtain a copolyamide-imide that exhibits a high elastic modulus comparable to that of a homopolymer and has a suitable elongation.More surprisingly, the copolyamide amic acid can be produced in an aqueous coagulation bath. It has been found that it exhibits good coagulation properties in wet molding using. Furthermore, in order to obtain copolyamide-imide fibers having the above-mentioned characteristics, the present invention was completed based on the realization that it is essential to enhance the molecular orientation at the early stage of the molding process. Thus, according to the present invention, a copolyamide amic acid mainly consists of structural units represented by the following formulas 1 to 2, wherein the molar ratio of each structural unit is the sum of 1 and II and II
A copolyamide uccinic acid characterized in that I is substantially equal and the ratio of ■ and II satisfies the following formula (a), (wherein R is an alkyl group having 1 to 4 carbon atoms)■ Ni oc - @) -c O- (However, X is an alkyl group or alkoxy group having 1 to 2 carbon atoms, n is an integer of 1 to 2) (a) mx / mz = 95/ 5 to 10
/ 90 and, when spinning a molding dope mainly composed of the copolyamide amic acid according to claim (1) to form a copolyamideimide fiber, the dope is once discharged into an inert atmosphere and then put into an aqueous coagulation system. A method for producing a copolyamide-imide fiber is provided. The present invention will be explained in detail below. The copolyamide amic acid of the present invention essentially includes pyromellitic diaanhydride (and/or its derivatives) and terephthalic acid (and/or its derivatives) as acid components.
As the diamine component, the following alkyl and/or
Alternatively, it can be synthesized by conventional solution polymerization from alkoxy-substituted benzidine. Here, "mainly '°" means that 95 mol% or more of the acid component of the copolyamide amic acid is the above I or ■, and 95 mol% or more of the diamine component is the above 1, and If the constituent components are mixed outside of this range, problems such as deterioration of the mechanical properties of the resulting copolyamide-imide may occur.
The purpose of the invention cannot be achieved. In order to achieve the object of the present invention, it is further necessary to keep the copolymerization composition of I and II within the above range. If (2) is used above this range, the solubility, wet moldability, and elastic modulus of the polymer will decrease, and conversely, if (2) is used below this range, the elongation will decrease. Also, preferably ms/mz:
When the range of 90/10 to 15/85 is satisfied and 1 and 2 are present, the resulting fiber will have better mechanical properties. In addition, if high heat resistance is required, rot/m2
Although it is particularly preferable that m 17 m 2 be 90/10 to 50,150, it may be preferable to perform constant length heat treatment to obtain excellent fiber physical properties even when m 17 m 2 is 50/50 to 10/90. . Next, the following diamine components are important in providing the copolyamide amic acid with good wet moldability used in the present invention. 3.3'-dimethylbenzidine, 3,3'-diethylbenzidine, 3.3', 5,5'-te)-ramethylbenzidine, 3.3'-dimethoxybenzidine, 2,2'-
Dimethylbenzidine. Incidentally, it is also possible to use an acid component and a diamine component without departing from the scope of the present invention. Examples of acid components include the following:

[Aromatic di#I anhydride]

3.3°, 4.4′-diphenyltetracarboxylic anhydride, 2,3.3′,4″-diphenyltetracarboxylic anhydride, 3.3°, 4.4′-diphenyloxytetracarboxylic anhydride 3,3", 4.4'-benzophenonetetracarboxylic anhydride, 3,3°, 4.4
'-Diphenylsulfone tetracarboxylic anhydride, 3
, 3°, 4.4'-diphenylalkylene 1-racarboxylic anhydride, 1.4-bis(3,4-dicarboxyphenoxy)benzenedic anhydride, 1,3-bis(3,
4-Dicarboxyphenoxy)benzenedic anhydride, p
-Phenylene-bisutrimellitate diacid anhydride.

[Tetracarboxylic acid derivative]

Diester diacid chloride of tetracarboxylic acids, diester of tetracarboxylic acids, salts of tetracarboxylic acids.

[Aromatic dicarboxylic acids, tricarboxylic acids] Isophthalic acid, 4,4°-diphenylcarphonic acid, 4.4゛-dicarboxydiphenyl ether, 2,6-naphthalene dicarboxylic acid and their diacid chlorides, diesters, trimellitic acid , trimellitic anhydride, trimellitic anhydride chloride. Further, examples of the diamine component include the following. p-phenylenediamine, 2-methyl-p-phenylenediamine, 2-ethyl-p-phenylenediamine, 2-
Methoxy-p-phenylenediamine', 2-ethoxy-
p-phenylenediamine, 2.5-dimethyl-p-phenylenediamine, 2.6-dimethyl-p-phenylenediamine, 2.6-dimethoxy-p-phenylenediamine, 2,3.5-trimethyl-p-phenylenediamine , 2,3.5-trimethoxy-p-phenylenediamine, 2,3,5.6-titramethoxy-p-phenylenediamine, metaphenylenediamine, 2,4-diaminotoluene, diaminobenzanilide, diaminodiphenyl ether, diaminobenzophenone , diaminodiphenylsulfone, diaminodiphenylsulfide, diaminodiphenylmethane, 22-bis(aminophenyl)
Propane, 1,4-bis(aminophenoxy)benzene, 1,3-bis(aminophenoxy)benzene, 4,4
゛-bis(aminophenoxy)diphenyl, 4,4°-
Bis(aminophenoxy)diphenyl ether, 4,4
゛-bis(aminophenoxy)diphenylsulfone,
2.2-bis((aminophenoxy)phenyl)propane, 2,2-bis((aminophenoxy)phenyl)hexafluoropropane, diaminonaphthalene and their hydrochlorides. The copolyamide amic acid of this invention is obtained by solution polymerizing the above-mentioned acid components (pyromellitic acid component and terephthalic acid component) and diamine component in a solvent.
The solvent used at this time will be described below. Any solvent may be used as long as it is non-reactive with the monomers used and dissolves the precursor at a high concentration, but the following solvents are preferably used because of the ease of mounting the plate. N-methyl-2-pyrrolidone (NMP), N-ethyl-
2-pyrrolidone (NEP), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DM
Ac ), N,N-diethylacetamide (DEAc
), N,N-dimethylpropionamide (DMPr),
N,N-dimethylbutyramide (NMBA), N,N-
Dimethylisobutyramide (NMIB), N-methyl lactam (MMC), N,N-dimethylmethoxyacetamide, N-acetylpyrrolidine (NAPr), N
-acetylpiperidine, N-methylpiperidone-2 (N
MPD), N, N'-dimethylethylene urea, N, N'
-dimethylpropylene urea, N, N, N', N'-tetramethylmalonamide, N-acetylpyrrolidone, N,
N, N', N'tetramethylurea (TNU), dimethyl sulfoxide (DMSO), hexamethylphosphoramide (HMPA). etc. Regarding solution polymerization, the usual method used for polymerizing polyamic acid is applied, but as shown in Example 1 below, NMP in which 3,3'-dimethylbenzidine was dissolved was used.
While keeping the solution at -10°C, pyromellitic anhydride and terephthalic acid chloride were added in approximately equal amounts to the above diamine and stirred vigorously. ! The P liquid gradually increases in viscosity,
When stirring was continued, a highly viscous solution was obtained, and the intrinsic viscosity was measured to be 10.5, confirming that a copolyamide amic acid with a high degree of polymerization was produced. Measurement of intrinsic viscosity (yzinh) was carried out in NMP at 35°C, concentration 0,
Using an Ostwanedo viscometer with 5"/old, 1/C[In(
t/l, o)]. Further, when using diester diacid chloride of tetracarboxylic acids or hydrochloride of diamine, solution polymerization may be carried out in the same manner, but at that time, it is preferable to add a dehydrochlorination agent such as a tertiary amine. As described above, the copolyamide amic acid of the present invention is synthesized. The copolyamide amic acid of the present invention uses a nuclear chlorine-substituted rigid diamine which is poor in reactivity and coagulation property in wet molding, and is expensive. Therefore, it can be molded by a simple process, and it is possible to achieve an extremely high degree of polymerization at low cost. It is also superior to chlorine-containing polyimide in terms of environmental pollution during combustion. The copolyamide amic acid thus obtained can be imide-converted by using a chemical cyclizing agent as described below or by heating to obtain a copolyamide-imide having excellent heat resistance and mechanical properties. Next, a method for producing a fiber that maximizes the latent performance of the copolyamide-imide, which is another object of the present invention, will be explained in detail.

[Preparation of molding dope]

To prepare a molding dope, a copolyamide amic acid solution subjected to solution polymerization is adjusted to a polymer concentration so as to have a viscosity suitable for molding, and the solution may be used as a molding dope as it is, or it may be mixed with a non-solvent. After the polymer is once isolated by such methods, it can be redissolved in an appropriate solvent and used as a molding dope.In the present invention, either method can be adopted, but the former method is preferred industrially. Since the molding solution made of the copolyamide amic acid of the present invention exhibits excellent coagulation properties in an aqueous coagulation solution, it can be used as a molding dope as is. proposed in Japanese Patent Application No. 63-226344, in which amines and/or metal salts of weak acids are added to a polyamic acid solution, or by adding a chemical cyclizing agent to a polyamic acid solution. Of course, a method of partially imidizing may also be used.

[Fiber manufacturing method]

As mentioned above, the production method of the present invention ultimately obtains high-grade fiber properties by increasing molecular orientation at the initial stage of molding. This can be achieved by first discharging the above-mentioned molding dope made of the copolyamide amic acid into an inert atmosphere and then introducing it into an aqueous coagulation system to perform wet molding. By doing this, it is possible to increase the spinning draft, improve molecular orientation, and by densifying the coagulation state on the fiber surface, it is possible to suppress the occurrence of defects such as voids, resulting in high performance. A fiber having the following characteristics is obtained. The inert atmosphere herein refers to an atmosphere that is substantially non-reactive with the dope, such as nitrogen, argon, or air, and air is preferably used for ease of use. In normal wet spinning, contact with a coagulant occurs at the same time as discharge, making it difficult to obtain a large spinning draft, and as the solidified surface is stretched, vertical grooves are formed in the direction of the fibers. and the occurrence of voids. According to the present invention, these not only make it difficult to proceed with sufficient molecular blending, but also create defects that are undesirable for improving mechanical properties, and further cause fibrillation. Both problems are solved at the same time. The production method of the present invention can be applied to ordinary polyimide fibers, but in order to obtain fibers with excellent mechanical properties, which is the object of the present invention, it is necessary to use a specific polyamide amic acid as a precursor. When the silk-making method of the present invention is applied to a certain normal polyimide precursor, for example, a precursor of pyromellitimide whose diamine component is a rigid diamine such as p-phenylenediamine or benzidine, the orientation and physical properties of the coagulated yarn On the other hand, it becomes almost impossible to carry out hot drawing after the fact, and high mechanical properties cannot be expected, and only a fragile yarn with low elongation can be obtained. Due to poor production, the uncoagulated threads are devitrified due to voids, etc. Moreover, in polyimide into which bent chains have been introduced, the latent performance itself is deteriorated to begin with, and the effects of the present invention cannot be fully exhibited. The present invention aims to pursue the simplest process, and therefore uses an aqueous coagulation bath, which is different from the method using an alcohol-based coagulation bath as disclosed in Japanese Patent Publication No. 57-37687. This is because, in comparison, there is nothing superior to water-based systems in terms of ease of handling. To explain the aqueous coagulation bath in more detail, it is preferably composed of water or water and a solvent constituting the precursor solution, and may contain an inorganic compound for the purpose of improving coagulation properties. The coagulated yarn is then subjected to an appropriate process and then subjected to hot drawing and heat treatment, or a combination of both hot drawings to finally obtain fibers with excellent mechanical properties. Examples of the above processes include: (1) Hot stretching the coagulated thread. (2) After stretching the solidified system in the air or in an aqueous solution, hot stretching is performed. (31) The coagulated thread is imidized and then hot-stretched. (4) The coagulated thread is stretched in air or in an aqueous bath, then imidized, and then hot-stretched. In general, it is important to increase the fiber strength before hot drawing because hot drawing under as high a tension as possible leads to improved physical properties.In this sense, the method described above is preferable. However, in order to increase the fiber strength to some extent before hot drawing and pursue a simple process, method (2) can also be used.As for imidization, thermal imidization method by heating There is a chemical imidization method that uses a curing agent, and either method may be used, but the chemical imidization method is preferable in terms of suppressing crystallization, and the thermal imidization method is suitable in terms of simplifying the process. Next, the above chemical imidization method will be explained.

[Chemical imidization method]

This refers to the process of ring-closing imidization of the amic acid site of polyamide amic acid using a dehydrating agent such as acetic anhydride. At this time, a tertiary amine such as pyridine may also be used as a catalyst to increase the imidization rate. can. In the imidization of yarn, specifically, after coagulation, the yarn is wound onto a bobbin and then the whole bobbin is immersed in the above chemical cyclizing agent, or a single yarn after coagulation is chemically cyclized. The yarn may be brought into contact with the chemical cyclizing agent by a method such as passing through a bath containing a chemical cyclizing agent, and the method is not particularly limited, and the immersion time is several seconds or more. less than an hour. Also, at this time, the present inventors first applied for patent application No. 62-2723.
If the method of promoting imidization of threads proposed in No. 42 and Japanese Patent Application No. 63-226344 is used, imidization can be more efficiently progressed. The copolyamideimide obtained from the copolyamide amic acid of the present invention has reduced crystallinity during the molding process compared to homopolymers due to the substituent effect of the alkyl and/or alkoxy nuclear substituted benzidine and the copolymerization effect. Molecular orientation can be highly improved. The drawn yarn is preferably subjected to high-temperature heat treatment in order to further improve physical properties by promoting crystallization.
Processing is carried out at a temperature of ~650°C, preferably 475-600°C. Although the fibers obtained as described above are copolymers, they exhibit high elasticity, etc. 8 and also have appropriate elongation. The copolyamide amic acid of the present invention provides a copolyamide-imide with a low coefficient of thermal expansion that is useful in film and insulation coating applications, and the copolyamide-imide has very high utility value in the field of electronic materials. (Operations and Effects of the Invention) The most important feature of the copolyamide amic acid of the present invention is that it achieves a high degree of polymerization, which is advantageous in various mechanical properties, and although it is a copolymer, it exhibits a high modulus of elasticity and has moderate elongation. It is possible to obtain a copolyamide-imide molded article having a high degree of strength. The molded body is made of advanced composite materials (A, C,
M,,), exhibits excellent performance in the field of electronic materials, etc. Further, by applying the fiber manufacturing method of the present invention to the above-mentioned copolyamide amic acid, it becomes possible to obtain a fiber having excellent mechanical properties, that is, a high modulus of elasticity and a suitable elongation. Furthermore, the copolyamide amic acid of the present invention has specific excellent coagulation properties in an aqueous coagulation bath, which is the easiest to handle in a wet molding process, and there is no need to use various methods to improve coagulation properties. The process that requires practical use is the simplest one. (Example) Hereinafter, the present invention will be explained with reference to Examples. First, the preparation of the molding solution used in the present invention, the spinning method, and the heat treatment method were performed in accordance with the following.

[Preparation of molding stock solution]

N-methylpyrrolidone (
NMP) dissolved in 150 ml in a stream of dry nitrogen,
After this amine solution was externally cooled to -10° C., pyromellitic anhydride (PMDA) and terephthalic acid chloride were added in approximately equivalent amounts to the diamine and a polymerization reaction was carried out with high speed stirring. A part of the obtained high viscosity copolyamide amic acid solution was taken out and diluted to a concentration of 0.5 g/dl to ηin.
Measure h.

[Dry-wet spinning (spinning method A)]

The copolyamide amic acid solution obtained as described above was immediately mixed with a pore size of 0. IIWl, discharged into the air at a discharge speed of 3 m/l 1 inch through a nozzle with 12 holes, and after passing through an air layer with a thickness of 10 mm, water/NMP (volume ratio 90/1
After passing through the bath for about 3 m, it was drawn to about twice its original size in a stretching bath consisting of water/NMP (volume ratio 9515), and then released into the air. 2
Wind up at 0m/l1in. (Hereinafter, this will be referred to as spinning method A.)

[Wet spinning (spinning method B) 1 All procedures are carried out in the same manner as spinning method A, except that the above copolyamide amic acid solution is not passed through the air layer.
Hereinafter, this will be referred to as the spinning B method.)]

[Chemical imidization - heat treatment (heat treatment method A)] Immediately, the wound yarn is treated with acetic anhydride/pyridine (volume ratio 70/30) in a separate bobbin.
The yarn was immersed in Raku for 1 hour to advance imidization, washed with water and dried, and then heated at 250°C and 450-600°C.
'C (the optimum value is selected depending on the copolyamide amic acid used) is subjected to stepwise temperature elevation heat treatment on a plate to obtain a copolyamide-imide fiber. At this time, stretching is carried out at a ratio that allows stable winding (hereinafter referred to as heat treatment method A) - (thermal imidization (heat treatment method B)) In the above spinning methods A and B, When taking the yarn, it is passed through a hot roller heated to about 100°C, and the dried yarn is subjected to stepwise heating heat treatment on a plate at 250°C and 450 to 600°C (the optimum value is selected depending on the copolyamide amic acid used). At this time, the copolyamide-imide fiber is drawn at a ratio that allows stable winding. (Hereinafter, this is referred to as heat treatment method B.) In the examples, the intrinsic viscosity (ηinh) is determined at a polymer concentration of 0.5 g/old. Dilute the precursor solution with a solvent so that
This is a value measured at 35°C. In addition, the tensile properties were determined using Tensilon manufactured by Toyo ■, with a paper length of 100 and a tensile speed of 50.
The yarn was measured in terms of m/lfn, and a difference of up to about 20% in tensile properties was observed between the single yarn and the yarn. The abbreviations of compounds used in the examples are as follows. PMDA: Pyromellitic anhydride DPDA: 3,3°,4,4'-diphenyltetracarboxylic anhydride TACL: Terephthalic acid chloride IACL: Isophthalic acid chloride m-TOL: 2,2°-dimethylbenzidine DSB: 3
, 3°-dimethoxybenzidine 3CBZ: 3,3'-dichlorobenzidine 2CBZ: 2,2'-dichlorobenzidine 2CP: 2-chloro-p-phenylenediamine 25
CBZ: 2,2°, 5,5°-tetrachlorobenzidine PPDA: p-phenylenediamine 4DAPB: 4,4°-diaminodiphenyl ether MPDA: River-phenylenediamine Example 1 3.3′-dimethylbenzidine (hereinafter referred to as o -Tol)3
．． 211r, PMDA 2.64 g, and terephthalic acid chloride (hereinafter referred to as TACL) 0.62 g (molar ratio of acid components 80/20) were polymerized by the above-mentioned molding stock solution preparation method to obtain a copolyamide amic acid molding stock solution. ηn
h was 10.5, and a copolyamide amic acid with a high degree of polymerization was polymerized. Hereinafter, various copolyamide amic acids were polymerized with various changes in the acid component and diamine component. The results are shown in Table-1. Comparative Example 1 A copolyamide amic acid was polymerized according to the method described above using various aromatic diamines substituted with nuclear chlorine as the diamine component and PMDA and TACL as the acid component. The results are also shown in Table 1, and the degree of polymerization was much lower than in Example 1. Table *: Polymer Precipitation Example 2 - The copolyamide amic acid solutions 1 to 12 of Example 1 were wet-dry spun using the above-mentioned spinning method A, and then heat-treated using methods A and B to form copolyamide-imide. m fibers were obtained. The physical properties of the obtained fibers are shown in Table 2. (The heat treatment temperature was varied, and the one that showed the best physical properties was described. The same applies hereafter.) All fibers had a strength of 15+r/de or more, an initial elastic modulus of 1200 g/d8 or more, and a breaking elongation of 1.5.
% or more, showing excellent physical property values. The coagulation properties during spinning were also good, and the coagulated yarn bundle was almost transparent. Comparative Example 2 Copolyamide amic acid solutions 3 to 8 of Comparative Example 1 were wet-dry spun using the above-mentioned spinning method A, and heat treated using heat treatment method A to obtain copolyamide-imide fibers. The physical property values of the obtained fibers are also listed in Table 2. Compared to the copolyamide-imide fiber of Example 2, the physical properties were clearly inferior. Moreover, the spun yarn bundle had poor coagulation properties and was devitrified compared to that of Example 2. Table Comparative Example 3 - Regarding the copolyamide amic acid of Example 2, spinning method B (wet spinning method) and heat treatment method A were employed to obtain copolyamideimide fibers, and the results are shown in Table 3. Compared to Example 2, the physical properties were significantly inferior. Comparative Example 4 Various homoboriamiducic acids using the acid components and diamine components listed in Table 4 were obtained according to the above method, and spinning A
A corresponding polyamide-imide fiber was obtained by heat treatment method A. A polyamic acid with a high degree of polymerization of 0, whose intrinsic viscosity and fiber physical properties are shown in Table 4, was obtained,
Although a fiber having a high elastic modulus was obtained, the elongation was insufficient compared to Example 2. Example 3. Comparative Example 5 A copolyamide amic acid solution was obtained in which the copolymerization ratio of the acid component and the diamine component was varied, and a copolyamide-imide fiber was obtained by spinning method A and heat treatment method A, and the physical property values are listed in Table 5. . It has become clear that the physical properties decrease as the copolymerization ratio deviates from the range of the present invention. Table 5 Comparative example of polymer precipitation during polymerization 6 A copolyamide amic acid solution was produced using an acid and diamine other than those specified in the present invention, and a copolyamide-imide fiber was obtained by spinning method A and heat treatment method A, and its physical properties The values are listed in Table-6. Compared to Example 2, physical property values were unbalanced. Table 6 Example 4 Pyridine was added to each copolyamide amic acid solution obtained in Example 1 in an amount of 0.3 equivalents of amic acid units, and the resulting solution was used as a molding dope to perform spinning method A and heat treatment method A. Corresponding copolyamide-imide fibers were obtained. The physical property values are shown in Table-7. The coagulability was further improved, and the physical properties were improved compared to Example 2. Procedural proceedings dated July 1999, day 1 temple office director 1 sweeton 1, matter fl indication patent application no. 2, name of invention Manufacturer of copolyamide amic acid and copolyamideimide fiber 300) The Teijin Limited patent claims are amended as shown in the attached sheet. On page 11, line 8 of the specification, the phrase “ratio is below” has been replaced with “ratio (r
) is corrected to J below. On page 11, line 12, the statement ``R is the number of carbon atoms'' is corrected to ``R is hydrogen or the number of carbon atoms''. (4) Insert "(where r is the molar ratio of I/If)" between the third and fourth lines of page 12. In the following part of Akira ms, it says [ml / mz J]
Correct to J. (1) Page 12, line 3 01) Page 13, line 11 (a) Page 13, lines 14-15 (f) Page 13, line 16 Attachment Claims (1) Mainly the following - Formula 1 A copolyamide amic acid consisting of constitutional units represented by ~ ■, in which the molar ratio of each constitutional unit is substantially equal to the sum of ■ and II and III, and the ratio D of ■ and II is as follows (ω A copolyamide 7mic acid characterized by satisfying the formula (wherein R is hydrogen or an alkyl group having 1 to 4 carbon atoms) (wherein, X is an alkyl group having 1 to 2 carbon atoms or an alkoxy group, n is an integer from 1 to 2) (ω r=95
15 to 10/90 (where r is the molar ratio of I/n) (a) When spinning a molding dope mainly consisting of the copolyamide amic acid according to claim (1) to form a copolyamide imide mixture, the dope 1. A method for producing copolyamide-imide I miscellaneous, which comprises discharging the mixture into an inert atmosphere and introducing the mixture into an aqueous coagulation bath.

Claims (1)

[Claims] (1) A copolyamide amic acid mainly consisting of structural units represented by the following general formulas I to III, in which the molar ratio of each structural unit is substantially equal to the sum of I and II and III, and I and II A copolyamide acic acid characterized in that the ratio thereof satisfies the following formula (a). I: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ and/or ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, R is an alkyl group with 1 to 4 carbon atoms) II: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ III: ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (However, X is an alkyl group or alkoxy group with 1 to 2 carbon atoms, n is an integer of 1 to 2) (a) m_1/m_2 = 95/5 to 10/ 90(2) When spinning a forming dope mainly composed of the copolyamide amic acid according to claim (1) to form a copolyamideimide fiber, the dope is once discharged into an inert atmosphere and then placed in an aqueous coagulation bath. A method for producing a copolyamide-imide fiber, characterized in that it is introduced into a copolyamide-imide fiber.