JPH1087987A - All aromatic polyamide-based composition and film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a para-type crosslinkable all aromatic polyamide film having excellent mechanical properties and chemical resistance, to provide a composite film of a para-type crosslinkable all aromatic polyamide and a polyimide having remarkably improved mechanical properties and chemical resistance, and to provide an all aromatic polyamide composition containing a general-purpose organic solvent and, usable as a raw material for the films. SOLUTION: This all aromatic polyamide composition contains (A) a para- type all aromatic polyamide containing a brominecontaining terephthalic acid as a monomer component and (B) an organic solvent as essential components. The weight fraction of the all aromatic polyamide A is 0.5-20%. As an alternative, the composition contains (A) an all aromatic polyamide, (B) an organic solvent and (C) a polyamic acid, the weight fraction of the component A is 0.5-20% and that of the polyamic acid C is 0.5-30%. The all aromatic polyamide film and the composite film of an all aromatic polyamide and a polyimide can be produced from the above compositions by removing the organic solvent B and heating at 220-350 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a wholly aromatic polyamide-based composition and to a wholly aromatic polyamide-based film obtained from the composition and having excellent mechanical properties and chemical resistance.

[0002]

[Prior Art] Journal of Polymer Science: Part A: Po
lymer Chemistry, No. 30, p. 1111, in 1992, there is a description relating to the cross-linking of a para-type wholly aromatic polyamide having fluorine, chlorine, bromine and iodine which are halogen groups in a terephthaloyl group. Wholly aromatic polyamides,
There is described an attempt to improve the compression resistance of these polymer fibers by covalently crosslinking between terephthaloyl groups with the dehalogenation of polybenzobisthiazole.

[0003] However, there is no mention of the solubility of these wholly aromatic polyamides in organic solvents, and furthermore, the processability of film from a solution state to a film, and requires high temperature conditions for crosslinking. I have. Further, the properties of the obtained wholly aromatic polyamide were not improved as compared with the para-type wholly aromatic polyamide having no halogen group, and the effect of introducing the halogen group was not clear.

Also, US Pat. No. 5,030,36 discloses a para-type wholly aromatic polyamide yarn (fiber) having chlorine in a terephthaloyl group. No mention is made of the processability from a solution state to a film, and there is no description of those having bromine as a halogen group.

Further, US Pat. No. 5,100,434 discloses that dehalogenation of at least 0.05 atom per polymer unit of polybenzobisthiazole having a halogen group is carried out. Needs and is limited to fiber. Further, since polybenzobisthiazole itself is hardly soluble in an organic solvent, it is extremely difficult to form a film from a solution using an organic solvent.

[0006] Para-type wholly aromatic polyamides have essentially excellent mechanical properties, but, on the other hand, are sparingly soluble and infusible in organic solvents, and are not suitable for processing or complexing with other polymers. Using a special solvent such as J. Macromol. Sci.-
Phys., B17 (4), p.591, 1980). This has practically many problems, and particularly when a composite with another polymer is to be obtained, for example, in the case of a composite with polyimide, a problem occurs in that the polyamic acid of the precursor is easily decomposed into an acid.

[0007] Further, the above-mentioned publicly-known documents include the formation of a film of the wholly aromatic polyamide using an organic solvent and the mechanical properties and the resistance of the polyimide film obtained by compounding the wholly aromatic polyamide with the polyimide using an organic solvent. No significant improvement in chemical properties is described.

On the other hand, polyimide has applications as a high-performance film material, but as a known technique from the viewpoint of improving its properties, 3,3 ', 4,4'-biphenyltetracarboxylic anhydride and 4,4' Journal of Polymer Science: Part C, Vol. 26, High elastic modulus and strength of wholly aromatic polyimide obtained from '-diaminodiphenyl ether
215 (1988).

That is, a wholly aromatic polyimide having a more rigid structure and obtained from 3,3 ', 4,4'-biphenyltetracarboxylic anhydride and paraphenylenediamine having a more rigid structure is added as a reinforcing component. Thus, a method for realizing high elastic modulus and high strength has been proposed. These polyimides are hardly dissolved in an organic solvent, and it is difficult to form a complex with another polymer in a solution state.

Therefore, the mixture is mixed in the state of a soluble polyamic acid, which is a precursor of polyimide, and then imidized by removing the solvent and subjecting the polyamic acid (also referred to as polyamic acid) to imidization by ring closure by treatment at a high temperature. Complex has been prepared. However, the composite obtained by this method is still basically a polyimide material, and a sufficient improvement in chemical resistance cannot be obtained.

Further, when the composite made by this known technique is stretched, the drawback is that the stability of the stretching is insufficient because the composite of polyamic acids is stretched, so that hot stretching in a short time cannot be performed. There is.

In recent years, a method of uniformly compounding a wholly aromatic polyamide soluble in an organic solvent with a wholly aromatic polyimide, that is, using a mixed solution of a non-para type wholly aromatic polyamide and polyamic acid, Attempts to improve the mechanical properties of polyimide films by uniformly compounding a wholly aromatic polyamide of the type with polyimide have been reported by Polymer Preprints Japa.
n Volume 41, No. 3, p. 985 (1992), and Polymer Prepri
nts Japan, vol. 40, No. 3, p. 776 (1991).

However, even with this method, a sufficient improvement in the chemical resistance of polyimide has not yet been achieved. In addition, the use of non-rigid non-para type wholly aromatic polyamide does not sufficiently improve mechanical properties such as elastic modulus.

[0014]

An object of the present invention is to provide a para-type cross-linkable wholly aromatic polyamide film having excellent mechanical properties and chemical resistance, and a marked improvement in mechanical properties and chemical resistance. An object of the present invention is to provide a composite film of a para-type crosslinkable wholly aromatic polyamide and a polyimide, and a wholly aromatic polyamide-based composition containing a general-purpose organic solvent as a raw material of these films.

[0015]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above object, and have found that a crosslinkable para-type wholly aromatic polyamide having a bromine group in a terephthaloyl group is dissolved in an organic solvent. It is possible to form a film from the composition, and the mechanical properties of the composite film obtained by forming a film using a composition containing both the wholly aromatic polyamide and the polyamic acid of the polyimide precursor and The present inventors have found that the chemical resistance is remarkably superior to that of a film of polyimide alone, and have completed the present invention.

That is, the present invention comprises a para-type wholly aromatic polyamide (A) containing terephthalic acid containing a bromine atom as a monomer component and an organic solvent (B) as essential components. A wholly aromatic polyamide-based composition having a weight fraction of 0.5 to 20%.

More specifically, the present invention is characterized in that the wholly aromatic polyamide (A) comprises, as dicarboxylic acid monomers, bromoterephthalic acid or other bromoterephthalic acids having a substituent on an aromatic ring, and diamine monomers as diamine monomers. A wholly aromatic polyamide composition characterized by being obtained from p-phenylenediamine or p-phenylenediamine having a substituent on an aromatic ring or p-phenylenediamine having a substituent on nitrogen,

It contains a wholly aromatic polyamide (A), an organic solvent (B) and a polyamic acid (C), wherein the weight fraction of (A) is 0.5 to 20% and the weight fraction of polyamic acid (C) is A wholly aromatic polyamide-based composition having a ratio of 0.5 to 30%,

The polyamic acid (C) is obtained especially from pyromellitic anhydride or 3,3 ', 4,4'-biphenyltetracarboxylic anhydride and one or more aromatic diamines. And a wholly aromatic polyamide-based composition.

Further, the present invention comprises a para-type wholly aromatic polyamide (A) containing terephthalic acid containing bromine atom as a monomer component and an organic solvent (B) as essential components, and a weight of the wholly aromatic polyamide (A). A wholly aromatic polyamide-based film obtained by removing the organic solvent (B) from the wholly aromatic polyamide-based composition having a fraction of 0.5 to 20% and heating at a temperature of 220 ° C to 350 ° C;

It contains a wholly aromatic polyamide (A), an organic solvent (B), and a polyamic acid (C), wherein the weight fraction of (A) is 0.5 to 20% and the weight fraction of polyamic acid (C) is Wherein the organic solvent (B) is removed from the wholly aromatic polyamide-based composition, and the polyamic acid is dehydrated and ring-closed to form a polyimide. The weight fraction of (A) is 1 to 60%
And a wholly aromatic polyamide-based film characterized by having a weight retention of at least 45% by weight in concentrated sulfuric acid.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The para-type wholly aromatic polyamide (A) containing a terephthalic acid containing a bromine atom (bromine group) as a monomer component in the present invention means a terephthalic acid having a bromine atom on an aromatic ring as a dicarboxylic acid monomer component, It means an aromatic polyamide obtained by polycondensing diamine as a diamine monomer component.

The terephthalic acid having a bromine atom in the aromatic ring refers to a terephthaloyl group having one or more bromine atoms. In the aromatic ring, a substituent other than bromine is present together with bromine. You may. Examples of the aromatic diamine include p-phenylenediamine and p-phenylenediamines having a substituent on an aromatic ring and / or nitrogen.

As a combination of the dicarboxylic acid monomer and the diamine monomer, a combination of bromoterephthalic acid and p-phenylenediamine is particularly preferred from the viewpoint of obtaining particularly excellent mechanical properties. The wholly aromatic polyamide (A) may be obtained in combination with another type of monomer component to be polymerized.

The method for synthesizing the wholly aromatic polyamide (A) from these monomers is not particularly limited, but a so-called low-temperature polymerization method in which carboxylic acid is once acylated and then subjected to polymerization, or a direct polymerization method in which carboxylic acid is used as it is. Can be mentioned. The inherent viscosity of the obtained wholly aromatic polyamide (A) in concentrated sulfuric acid is 2.0 dL /
g or more is preferable.

According to the present invention, the wholly aromatic polyamide (A) has good affinity for the organic solvent (B) and gives a wholly aromatic polyamide-based composition (I) completely dissolved in the organic solvent. The organic solvent (B) referred to in the present invention is preferably a general-purpose amide type solvent, and typical examples thereof include N-methyl-2-pyrrolidinone (NMP), N, N-dimethylacetamide, N, N, N ′. , N'-tetramethylurea, of which NMP is preferred.

The dissolution of the wholly aromatic polyamide (A) in the organic solvent (B) can be easily achieved by stirring at room temperature. It is not necessary to add a metal salt or the like usually used for increasing the solvent's dissolving power. The concentration of the wholly aromatic polyamide (A) in the wholly aromatic polyamide-based composition (I) here is in the range of 0.5% by weight to 20%, and the wholly aromatic polyamide-based composition (I) Is almost uniform and transparent. The excellent solubility of the wholly aromatic polyamide (A) of the present invention is due to the effect of introducing a bromine group. That is, it is considered that the presence of the bulky bromine group suppresses the cohesive force between the polyamide chains, and that the affinity for the solvent is increased as a factor of the expression of solubility.

For example, poly (p-phenylene terephthalamide), which is a typical example of para-type wholly aromatic polyamide, is
Processing from an organic solution is very difficult because it is very insoluble in an organic solvent, and special processing from a concentrated sulfuric acid solution is required. However, poly (p-phenylene bromoterephthalamide) obtained by introducing bromine into the terephthaloyl group of this polymer becomes easily soluble in an organic solvent, and is excellent in processability from an organic solution to a film or the like.

In the present invention, a wholly aromatic polyamide film can be obtained by evaporating the organic solvent (B) from the wholly aromatic polyamide composition (I) by a solvent casting method. The conditions for such casting are not particularly limited, but the casting can be performed, for example, at a temperature of 50 ° C to 150 ° C in air or an inert gas atmosphere.

The obtained film is tough and flexible and has excellent mechanical properties. By subjecting the wholly aromatic polyamide film of the present invention to heat treatment, bromine groups are eliminated and crosslinking proceeds, and resistance to strong acids and the like is developed. The degree of cross-linking of the wholly aromatic polyamide-based film was determined by elemental analysis.
The terephthalic acid can be used as a dicarboxylic acid monomer component, and the aromatic diamine can be used as a diamine monomer to polymerize the diamine monomer. % Is preferable.

If the degree of cross-linking exceeds 2%, the strength is reduced and the composition becomes brittle. Regarding the lower limit of the degree of crosslinking of the wholly aromatic polyamide-based film of the present invention, even with a very small amount of bromine released within a measurement error range of the elemental analysis method, the resistance to strong acids and the like is sufficiently improved. However, it is difficult to specifically exemplify them as numerical values.

However, as a specific heating condition for crosslinking, a temperature condition of 220 ° C. to 350 ° C. is required. Although the heating time depends on the temperature, for example, conditions such as 6 hours at 250 ° C. and 3 hours at 350 ° C. can be mentioned. Thus, a wholly aromatic polyamide film having mechanical properties and sufficient chemical resistance is obtained. The heating required for the crosslinking may be carried out by a method of gradually elevating the temperature and elevating the final temperature to 220 ° C. or higher, together with the evaporation of the solvent from the composition.

In the wholly aromatic polyamide composition (I), by coexistence of another polymer soluble in the organic solvent (B) in addition to the wholly aromatic polyamide (A), both polymers are dissolved together. Wholly aromatic polyamide composition (I
I) can be prepared, and by evaporating the organic solvent (B) from the wholly aromatic polyamide-based composition (II), it is possible to obtain a uniform composite containing both polymers as constituent components.

According to this method, the wholly aromatic polyamide (A) and the polyamic acid (C), which is a precursor of the polyimide, are dissolved in the organic solvent (B), and the homogeneous and transparent wholly aromatic polyamide composition (II) To obtain a composite of a wholly aromatic polyamide (A) and a polyamic acid (C) by removing the organic solvent (B) from the composition, and then performing a ring-closing reaction of the polyamic acid (C). Thereby, a uniform composite of the wholly aromatic polyamide (A) and the polyimide can be obtained.

The polyamic acid (C) used herein is not particularly limited as long as it is soluble in the organic solvent (B), but is aromatic in that it gives a polyimide having sufficient heat resistance and mechanical strength. It is preferable to have an aromatic ring, and typical examples thereof include pyromellitic anhydride or 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride and at least one aromatic diamine. Examples thereof include those obtained by the reaction.

The aromatic diamine referred to in the present invention is p
-Phenylenediamine, m-phenylenediamine, 1,
5'-diaminonaphthalene, 1,8-diaminonaphthalene, 2,3-diaminonaphthalene, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 3,
3′-diaminodiphenylsulfone, 3,4′-diaminodiphenylsulfone, 4,4′-diaminodiphenylsulfone, 3,3′-diaminodiphenylmethane, 3,
It means 4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 3,3'-diaminobenzophenone, 3,4'-diaminobenzopheno, 4,4'-diaminobenzophenone and the like.

For example, pyromellitic anhydride and 4,4 '
-Diaminodiphenyl ether, or 3,3 ',
4,4'-biphenyltetracarboxylic anhydride and 4,
From a polyamic acid obtained from 4'-diaminodiphenyl ether, a wholly aromatic polyimide currently widely used as a film material can be obtained.

The reaction between the acid anhydride and the diamine can be carried out at about room temperature in the organic solvent (B), and is obtained as a solution in which the polyamic acid (C) is completely dissolved in the organic solvent (B). Can be This solution is mixed with a wholly aromatic polyamide (A) which is solid or previously dissolved in an organic solvent (B), so that the wholly aromatic polyamide (A) and the polyamic acid (C) which is a precursor of the polyimide are mixed with the organic solvent. Solvent (B)
To obtain a uniform and transparent composition.

The term "transparent" as used herein means no turbidity, and does not mean colorless. The mixing operation can be performed at room temperature. By removing the organic solvent (B) from the composition, a composite of the wholly aromatic polyamide (A) and the polyamic acid (C) can be obtained.

For example, when a film is obtained by a solvent casting method, the wholly aromatic polyamide composition (II) is cast into a mold, and then the solvent (B) is volatilized and removed to obtain a composite. The evaporation temperature of the solvent at this time is preferably in the range of 40C to 150C, more preferably 60C to 100C. In addition, it is particularly effective to carry out the process under an air current or under a temperature rising condition. By removing the solvent, tack-free, transparent and uniform,
A uniformly transparent composite film of the wholly aromatic polyamide (A) and the polyamic acid (C) is obtained.

The weight fraction of the wholly aromatic polyamide (A) in the composite of the present invention can be arbitrarily set, but may be from 1% to 1%.
Preferably it is 60%. If the weight fraction of the wholly aromatic polyamide (A) is less than 1%, the properties as a composite will not be sufficiently exhibited, and if it exceeds 60%, the strength will decrease.

The composite film thus obtained can be further stretched. By stretching, the wholly aromatic polyamide is oriented, which is extremely effective for improving mechanical properties. Since the aromatic polyimide has poor molecular chain mobility, stretching is difficult. It is preferable to perform stretching in the state of a precursor polyamic acid having molecular chain mobility. However, although stretching with the polyamic acid (C) alone is possible, it is extremely difficult to obtain a stretching ratio of 100% or more stably because it is too flexible.

A composite obtained from a uniform and transparent composition obtained by dissolving the wholly aromatic polyamide (A) of the present invention and a polyamic acid (C) which is a precursor of polyimide in an organic solvent (B) is as follows: Both properties are well-balanced, and the stretchability is excellent as compared with the case of each alone, and the stretch ratio of 100% or more is facilitated. The stretching temperature may be within a temperature range in which the stretching can be stably performed, and for example, the stretching can be stably performed at a temperature of 20 ° C. to 420 ° C.

When the composite is stretched, if the weight fraction of the polyamide (A) contained in the composite is 1 to 15%, the stretching temperature is 20 to 310 ° C. and the weight of the polyamide (A) is When the fraction is 16 to 40%, the stretching temperature is 290 to
At 410 ° C., the weight fraction of polyamide (A) is from 41% to 6%.
At 0%, stretching is preferably performed at a stretching temperature of 350 to 420 ° C.

Under these stretching conditions, a stretching ratio of 10
The stretching of 0% is substantially achieved within 10 seconds, and the polyamic acid (C) partially closes the ring to form a polyimide, but the ring closing reaction is not completed, and sufficient stretchability is secured. Here, the stretching ratio is defined by the following equation.

[0046]

Formula 1: stretching ratio (%) = (length after stretching−length before stretching) / (length before stretching) × 100

Next, the polyamic acid in the composite is dehydrated and ring-closed to form a composite of a wholly aromatic polyamide and polyimide. As a method of such dehydration ring closure, a heat treatment at a high temperature can be mentioned, and the temperature range is 180 ° C to 600 ° C.
° C, preferably in the range of 250 ° C to 500 ° C. The heating time largely depends on the temperature conditions and cannot be specified unconditionally. For example, at 300 ° C., the heating time may be 2 to 3 hours. The heating atmosphere here is not particularly limited, for example, air,
Alternatively, an inert gas such as nitrogen or argon may be used.

In the course of this heat treatment, the polyamic acid (C) in the composite is dehydrated and ring-closed to form an imide ring to form a polyimide, and a composite film of a wholly aromatic polyamide and polyimide is obtained. The obtained composite film is a transparent film in which the wholly aromatic polyamide (A) and the polyimide are uniformly compounded, and the wholly aromatic polyamide (A) is 10%.
It preferably has no dispersed aggregate structure of 0 nm or more.
More preferably, it is finely dispersed to less than 0 nm.

The composite film of a wholly aromatic polyamide and polyimide obtained according to the present invention is excellent in chemical resistance in addition to mechanical properties such as tensile properties. Specifically, the tensile modulus is 950 kg / mm ² or more and the tensile strength is 40
A composite having a weight of at least kg / mm ² is obtained, and a composite having particularly excellent resistance to chemicals, especially to a strong acid such as concentrated sulfuric acid that can dissolve even a wholly aromatic polyimide is obtained.

Specifically, the weight retention in concentrated sulfuric acid is at least three times the weight fraction of the wholly aromatic polyamide (A), or
A film of a composite of a wholly aromatic polyamide and polyimide, which is 45% or more of the total amount of the composite, is obtained.

For example, a polyimide film obtained from polyamic acid (C) alone is concentrated sulfuric acid at 25 ° C. (concentration: 96).
%), But only 10%
By introducing about 100% by weight of the wholly aromatic polyamide (A), the weight retention of the film after immersion in concentrated sulfuric acid is 45%.
As described above, the content is remarkably improved, and the form as a film is maintained sufficiently even in concentrated sulfuric acid.

This indicates a strong interaction between the polyimide and the wholly aromatic polyamide (A), and suggests that a cross-link may have been formed between the two polymers that were uniformly composited. Surprisingly, when cross-linking is performed by heating at 300 ° C. for 3 hours as described in Examples described later, the complex of the wholly aromatic polyamide and the polyimide is more complex than the wholly aromatic polyamide (A) alone. Experimental results with higher resistance to strong acids were obtained, strongly suggesting the formation of crosslinks by both polymer components.

[0053]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. The examples illustrate specific embodiments of the present invention, and the scope of the present invention is not limited thereto. The evaluation methods used in the examples are as follows.

(1) Inherent Viscosity Using a 96% by weight sulfuric acid solution having a polymer concentration of 0.1 g / dL, the viscosity was determined at 30 ° C. by an ordinary method using an Ubbelohde viscometer.

(2) Observation by Electron Microscope A film sample was broken in liquid nitrogen, and an observation sample obtained by depositing platinum on the fractured surface was examined at a magnification of 20,000 times with a scanning electron microscope S-800 manufactured by Hitachi. Observed.

(3) Tensile Characteristics A film sample was cut into a width of 3 mm, and a tensile test was performed at 25 ° C. using an Autograph 2000 manufactured by Shimadzu Corporation at an initial gauge interval of 10 mm and a tensile speed of 1 mm / min. The intensity was determined as an average of four measurement points.

(4) Sulfuric Acid Resistance Test The sample was immersed in 96% by weight of sulfuric acid at 25 ° C. for 120 hours, and the retention of the shape of the sample was visually judged. Further, the film after immersion was sufficiently washed with distilled water, dried at 80 ° C., weighed, and the weight retention was calculated as a percentage (%) from the weight ratio before immersion.

(Example 1) In a three-necked flask equipped with a nitrogen inlet tube, a condenser and a stirring blade, 1.225 g (0.005 mol) of a monomer, bromoterephthalic acid, and 0.5407 g (0.005 mol) of p-phenylenediamine were used. To 50 mL of NMP, 10 mL of pyridine, 1 g of lithium chloride, 3 g of calcium chloride
At 115 ° C. and then 2.62
2. Add mL of triphenyl phosphite and at 115 ° C.
The condensation reaction of the monomer was performed for 5 hours.

The product was sufficiently washed in boiling methanol and then dried to obtain a light yellow poly (p-phenylene bromoterephthalamide) powder. The yield was 100% and the inherent viscosity was 2.5 dL / g. 1 g of the poly (p-phenylene bromoterephthalamide) thus obtained was dissolved in 99 g of NMP at room temperature with stirring to obtain a homogeneous and transparent composition.

After the obtained composition was cast on a glass plate, NMP was dried and removed at 80 ° C. in an air stream to obtain a poly (p-phenylene bromoterephthalamide) film. Next, Table 1 shows the results of a sulfuric acid resistance test of a film obtained by treating this film in air under the conditions of a heating temperature of 300 ° C. and a heating time of 3 hours. From the results of elemental analysis, no significant difference was found in the amount of bromine before and after the heating, which exceeded the measurement error range.

Example 2 The results of a sulfuric acid resistance test of a film obtained by performing exactly the same operation as in Example 1 except that the heating temperature of the film was changed from 300 ° C. to 350 ° C. Are shown in Table 1. The degree of crosslinking estimated from elemental analysis was 1.3%.

(Comparative Example 1) Light yellow poly (p-phenylene terephthalamide) powder was obtained by performing exactly the same operation as in Example 1 except that bromoterephthalic acid was changed to terephthalic acid (0.005 mol). Was. The yield was 100%. The inherent viscosity was 6.8 dL / g.
The resulting poly (p-phenylene terephthalamide) was poorly soluble in organic solvents, and it was not possible to obtain a uniform and transparent composition dissolved in the organic solvent, and thus it was not possible to prepare a film. .

The sulfuric acid resistance test of poly (p-phenylene terephthalamide) was performed on a powdery sample. Poly (p-
Phenylene terephthalamide) in air at a heating temperature of 30
Table 1 shows the results of the sulfuric acid resistance test of the samples treated under the conditions of 0 ° C. and heating time = 3 hours.

[0064]

[Table 1]

Example 3 33.08 g under a nitrogen stream
Of 3,3 ', 4,4'-biphenyltetracarboxylic anhydride and 22.52 g of 4,4'-diaminodiphenyl ether were reacted in NMP in 500 g at room temperature with stirring for 4 hours to obtain a homogeneous and transparent solution. An NMP solution of polyamic acid having a concentration of 10% by weight was prepared. 97.1 g of the obtained NMP solution of polyamic acid and 100 g of the composition obtained in Example 1 were mixed at room temperature to obtain a new uniform transparent composition.

After casting the obtained composition on a glass plate, NMP was dried and removed at 80 ° C. in an air stream to obtain a film of the composite of polyamic acid and poly (p-phenylene bromoterephthalamide). Obtained. The obtained film had transparency. The obtained film is divided into a plurality of 1c
It was cut into strip-shaped films of m width. Some of the strip films were stretched. 170 ° C, 200
Four different stretched films having draw ratios of 80%, 100%, 140%, and 160%, respectively, were obtained from stretching temperatures of 225C, 225C, and 350C.

The thus obtained one unstretched film (stretching ratio = 0%) and four kinds of stretched films were fixed on a metal frame, and heat-treated at 300 ° C. for 3 hours in air, and the stretching ratio = 0% , 80%, 100%, 140% and 1
A film of a composite of 60% of a total of five types of poly (p-phenylene bromoterephthalamide) and polyimide [poly (p
-Phenylene bromoterephthalamide) and polyimide = 10/90]. All of the composite films were pale yellow and had uniform and sufficient transparency.
In addition, electron microscopic observation confirmed that no aggregated structure was observed at all, and that both components were uniformly compounded.

The tensile modulus and tensile strength of the unstretched film and the stretched film are shown in FIGS. 1 and 2, respectively. Table 2 shows the results of the sulfuric acid resistance test performed using the unstretched film.

(Example 4) 25.2 g of the NMP solution of the polyamic acid obtained in Example 3 and 100 g of the composition obtained in Example 1 were mixed at room temperature to obtain a new uniform transparent composition. Was. After casting the obtained solution on a glass plate, NMP was dried and removed at 80 ° C. in an air stream to obtain a film of a composite of polyamic acid and poly (p-phenylene bromoterephthalamide). The obtained film had transparency.

The obtained film was cut into a plurality of 1 cm-wide strip-shaped films. Some of the strip films were stretched. By changing the stretching temperature at 300 ° C. and 400 ° C., 80% and 110%, respectively,
Was obtained. The obtained unstretched film (stretching ratio = 0%) and two types of stretched films were fixed to a metal frame, and heat-treated at 300 ° C. for 3 hours in air.
A total of three types of films of poly (p-phenylene bromoterephthalamide) and polyimide with a stretching ratio of 0%, 80% and 110% [weight ratio = 30/70] were obtained.

The films of the composites were all pale yellow with uniform and sufficient transparency. In addition, electron microscopic observation confirmed that no aggregated structure was observed at all, and that both components were uniformly compounded. FIGS. 1 and 2 show the tensile modulus and tensile strength of the unstretched film and the stretched film, respectively. Table 2 shows the results of the sulfuric acid resistance test performed using the unstretched film.

(Example 5) 10.3 g of the NMP solution of polyamic acid obtained in Example 3 and 100 g of the composition obtained in Example 1 were mixed at room temperature to obtain a new uniform transparent composition. . After casting the obtained solution on a glass plate, NMP was dried and removed at 80 ° C. in an air stream to obtain a film of a composite of polyamic acid and poly (p-phenylene bromoterephthalamide). The obtained film had transparency.

The obtained film was cut into a plurality of strip films each having a width of 1 cm. Some of the strip films were stretched. At a temperature of 400 ° C. during stretching,
A stretch ratio of 80% was obtained. The obtained one type of unstretched film (stretching ratio = 0%) and one type of stretched film were fixed to a metal frame, and heat-treated at 300 ° C. for 3 hours in air. A total of two kinds of composite films of poly (p-phenylene bromoterephthalamide) and polyimide [weight ratio = 50/50] were obtained.

The films of the composites were all pale yellow, uniform and sufficiently transparent. In addition, electron microscopic observation confirmed that no aggregated structure was observed at all, and that both components were uniformly compounded. FIGS. 1 and 2 show the tensile modulus and tensile strength of the unstretched film and the stretched film, respectively. Table 2 shows the results of the sulfuric acid resistance test performed using the unstretched film.

(Comparative Example 2) The NMP solution of the polyamic acid obtained in Example 3 was cast on a glass plate.
The NMP was dried and removed at ℃ to obtain a film of the polyamic acid. The obtained film was cut into a plurality of 1 cm-wide strip films. Some of the strip films were stretched. At stretching temperatures of 90 ° C. and 170 ° C., two types of stretched films having a stretching ratio of 80% and 100%, respectively, were obtained.

The obtained unstretched film (stretching ratio = 0%)
And two kinds of stretched films were fixed to a metal frame, and heat-treated at 300 ° C. for 3 hours in air, and the stretching ratio was 0% and 8%.
A total of three types of polyimide films of 0% and 100% were obtained. FIGS. 1 and 2 show the tensile modulus and tensile strength of the unstretched film and the stretched film, respectively. Table 2 shows the results of the sulfuric acid resistance test performed using the unstretched film.

[0077]

[Table 2]

[0078]

According to the present invention, a para-type crosslinkable wholly aromatic polyamide film having excellent mechanical properties and chemical resistance and a para-type crosslinkable wholly aromatic polyamide are uniformly introduced to obtain mechanical properties and resistance to chemicals. It is possible to provide a film of a composite of a wholly aromatic polyamide and a polyimide with significantly improved chemical properties, and a wholly aromatic polyamide-based composition containing a general-purpose organic solvent as a raw material of these films.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between a stretching ratio (%) and a tensile modulus (kg / mm ² ) of a composite of an aromatic polyamide and a polyimide and a film of a polyimide alone obtained in Examples 3 to 5 and Comparative Example 2 of the present invention. It is a figure showing a relation.

FIG. 2 shows a drawing ratio (%) and a tensile strength (kg / mm ² ) of a film of a composite of a wholly aromatic polyamide and polyimide and a polyimide alone obtained in Examples 3 to 5 and Comparative Example 2 of the present invention. It is a figure showing a relation.

Claims (7)

[Claims] 1. A wholly aromatic polyamide (A) comprising a para-type wholly aromatic polyamide (A) containing bromine atom-containing terephthalic acid as a monomer component and an organic solvent (B) as essential components.
A weight fraction of 0.5 to 20%. 2. A wholly aromatic polyamide (A) comprising bromoterephthalic acid or other bromoterephthalic acid having a substituent on an aromatic ring as a dicarboxylic acid monomer, and p-phenylenediamine or an aromatic ring as a diamine monomer. 2. The wholly aromatic polyamide-based composition according to claim 1, wherein the composition is obtained from p-phenylenediamine having a substituent on nitrogen or p-phenylenediamine having a substituent on nitrogen. 3. A method comprising a wholly aromatic polyamide (A), an organic solvent (B), and a polyamic acid (C), wherein the weight fraction of (A) is 0.5 to 20% and that of the polyamic acid (C) 3. The wholly aromatic polyamide-based composition according to claim 1, wherein the weight fraction is 0.5 to 30%. 4. The polyamic acid (C) is obtained from pyromellitic anhydride or 3,3 ′, 4,4′-biphenyltetracarboxylic anhydride and one or more aromatic diamines. The wholly aromatic polyamide-based composition according to claim 3, characterized in that: 5. The method according to claim 1, wherein the organic solvent (B) is removed from the wholly aromatic polyamide-based composition according to claim 1,
A wholly aromatic polyamide-based film obtained by heating at a temperature of 350 ° C. 6. The wholly aromatic polyamide (A), which is obtained by removing the organic solvent (B) from the wholly aromatic polyamide-based composition according to claim 3 or 4, and dehydrating and ring-closing the polyamic acid to form a polyimide. A) a composite film of a wholly aromatic polyamide and a polyimide, wherein the weight fraction of 1) is 1 to 60%. 7. The wholly aromatic polyamide-based film according to claim 5, wherein the weight retention in concentrated sulfuric acid is 45% by weight or more.