JPH07165915A - Aromatic polyamide-imide-based film - Google Patents

Abstract

PURPOSE:To obtain the inexpensive film useful for a base film for a magnetic recording medium of thin film type and a flexible printed board, having a high Young's modulus and stability to moisture and heat, containing a repeating unit of a specific structure in >= a specific ratio. CONSTITUTION:This film comprises repeating units composed of >=60mol% of a repeating unit of the formula (R1 to R3 are each benzene, naphthalene, anthracene and phenyl ring; molar ratio of (n) and (m) is 100:0 to 30:70). The film is obtained by dissolving a polyamidoamic acid or a polyamide-imide in an aprotic organic solvent to give a dope and forming a film from the dope. The film has preferably >=700kg/mm<2> Young's modulus in an undrawn state, <=2.5% moisture absorption ratio and preferably <=3% heat shrinkage percentage at 250 deg.C. The thickness of the film is perferably 1-50mum.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aromatic polyamideimide type film, and more particularly to a thin film type base film for magnetic recording media and an aromatic polyamideimide type film most suitable for a flexible printed circuit board. .

[0002]

2. Description of the Related Art Conventionally, aromatic polyamide and polyimide films have excellent mechanical properties, heat resistance, humidity properties, and electrical insulation properties, and are used as base films for magnetic recording materials, flexible printed boards, capacitors, thermal transfer ribbons, electrical insulation materials, etc. Widely used and considered by.

[0003]

However, recently, in order to miniaturize the device and improve its performance, mechanical properties, especially Young's modulus, dimensional stability due to humidity and heat are improved, and these high-performance films are expensive. Therefore, since the usable range is limited, there is a strong demand for inexpensive and thin films. However, at present, it is difficult to meet these requirements.

An object of the present invention is to solve the above problems and to provide a thin film which has a high Young's modulus, is stable against humidity and heat, and is inexpensive.

[0005]

In order to achieve the above object, the present invention comprises 60 mol% or more of repeating units.

[Chemical 2] The aromatic polyamideimide film, wherein n: m is a molar ratio of 100: 0 to 30:70 (wherein R ₁ , R ₂ , and R ₃ are benzene, naphthalene, anthracene, and biphenyl rings). And two or more of these may be contained, and each ring may have a substituent.).

In the present invention, 60 mol% of the repeating unit
It is necessary that the above is the constitutional unit represented by the above chemical formula, and if it is less than 40 mol%, other aromatic polyamide, polyimide are copolymerized, resins such as polycarbonate and polyester are blended within the scope of the object of the present invention.・
You can alloy it.

The polyamide-imide film of the present invention has a molar ratio of amide (n) and imide (m) of n: m of 100:
0 to 30:70, but preferably 0.2 to imide.
It is 50 mol%, and more preferably 0.3 to 30 mol%. Outside this range, the elongation of the film obtained by the wet film-forming method capable of effectively achieving the object of the present invention is small, which is not preferable. R ₁ , R ₂ , and R ₃ are benzene, naphthalene, anthracene, and biphenyl rings, and those having substituents such as chlorine, bromine, and nitro groups introduced into these rings have improved solubility and moisture characteristics of the film. It is preferable for improvement. In particular, the effects introduced into R ₁ and R ₂ are remarkable.

The positions of the aromatic ring and the amide and imide bonds, which form the basic skeleton of the film of the present invention, are not particularly limited, but for the purpose of use in magnetic recording applications and flexible printed circuit boards, a structure in which the molecular chain extends linearly,

[Chemical 3] However, considering the solubility of the dope and the ease of film-forming, a partially flexible structure, for example,

[Chemical 4] Is preferably introduced. The amount thereof is preferably 1 to 50 mol%, more preferably 1 to 30 in terms of molar ratio.
Mol%.

[0009] Examples of the monomer which is a constituent unit of the aromatic polyamide-imide film of the present invention include the following when taking an example of polymer synthesis from diamine, tetracarboxylic acid anhydride and diacid chloride. .

Paraphenylenediamine as the diamine,
Metaphenylenediamine, 2-chloroparaphenylenediamine, 2,6-dichloroparaphenylenediamine, 2
-Nitroparaphenylenediamine, 5-chlorometaphenylenediamine, 1,5-diaminonaphthalene, 2,6
-Diaminonaphthalene, 4,4'-diaminobiphenyl 3,3'-dimethyl-4,4'-diaminobiphenyl 3,3'-dimethoxy-4,4'-diaminobiphenyl and the like, pyromellitic acid as a tetracarboxylic acid anhydride Dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic dianhydride, etc. as diacid chloride, terephthalic acid chloride, isophthalic acid chloride, 2-
Chlorterephthalic acid chloride, 2,6-dichloroterephthalic acid chloride, 2-nitroterephthalic acid chloride,
2,6-naphthalenedicarboxylic acid chloride, 1,5-naphthalenedicarboxylic acid chloride 4,4′-biphenyldicarboxylic acid chloride and the like can be mentioned.

A diamine as a copolymerization component is 4,
4'-diaminodiphenyl ether, 3,4'-diaminidiphenyl ether, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminidiphenyl sulfone, 4,
4'-diaminodiphenylmethane, 4,4'-methylene-bis (2-chloroaniline), 2,2-bis [4-
(4-aminophenoxy) phenyl] propane, bis [4- (4-aminophenoxy) phenyl] ether,
4,4'-bis (4-aminophenoxy) biphenyl,
1,4-bis (4-aminophenoxy) benzene, 1,
3-bis (3-aminophenoxy) benzene, 1,3-
Tetracarboxylic acid anhydrides such as bis (4-aminophenoxy) benzene and 9,9-bis (4-aminophenyl) fluorene are 3,4,3 ′, 4′-benzophenone tetracarboxylic acid dianhydride and bis (3 , 4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride and the like.

The aromatic polyamideimide film of the present invention having the above constitution is excellent in high Young's modulus, heat resistance and hygroscopicity, and preferably has the following physical properties.

Young's modulus is 700 kg / m in an unstretched state
m ² or more, and more preferably 100
0 kg / mm ² , more preferably 1300 kg / mm
² or more. If the Young's modulus is less than 700 kg / mm ² , the thin film magnetic recording tape has poor running durability because the film is weak, and it is not effective enough for long-time recording and downsizing, and it is a thin substrate for flexible printed circuit boards. Has no effect on

The moisture absorption rate is preferably 2.5% or less, more preferably 2% or less, still more preferably 1.7% or less. If the moisture absorption rate exceeds 2.5%, the dimensional change due to moisture absorption of the magnetic recording tape becomes large and the recording characteristics and durability deteriorate, and the adhesiveness of the thin film deteriorates. Further, even in flexible printed circuit board applications, it becomes difficult to densify wiring due to changes in moisture absorption dimensions, there is a large change over time in the adhesiveness between metal and base film, and there are problems such as curling of the board. .

The heat shrinkage at 250 ° C. is preferably 3% or less, more preferably 2% or less, still more preferably 1.5.
% Or less. If the heat shrinkage ratio exceeds 3%, in thin film magnetic recording applications, heat loss during thin film formation causes a decrease in yield and deterioration of recording characteristics.

The elongation is 5% or more, preferably 10% or more,
It is more preferably at least 15%. If it is less than 5%, it may cause breakage during processing into a tape or during use.

The breaking strength is preferably 20 kg / mm ² or more, more preferably 25 kg / mm ² or more. The edge tear resistance is 1 kgf or more, preferably 2 kgf.
If it is less than 1 kgf, it may cause troubles during processing and use.

The density of the film of the present invention is 1.40 g / m.
It is preferably m ² or more and 1.60 g / mm ² or less. If it is less than 1.40 g / mm ² , the Young's modulus of the film is lowered and the moisture absorption rate and the heat shrinkage rate are increased, which is not suitable for practical use.
If it exceeds 1.60 g / mm ² , the obtained film becomes brittle and cannot be used practically.

The thickness of the polyamideimide film of the present invention having the above characteristics is preferably 1 to 50 μm, more preferably 1.5 to 30 μm, and further preferably 1.5.
Is about 25 μm. If the thickness is less than 1 μm, it is difficult to handle, and if it exceeds 50 μm, it is difficult to exert the effect of the present invention.

The aromatic polyamideimide type film having such characteristics is produced by solution casting from a dope prepared by dissolving a polyamide amide acid or polyamide imide in an aprotic organic solvent.

Polyamidoamidic acid and polyamidoimide are obtained by reacting diamine with tetracarboxylic dianhydride or diacid chloride at low temperature and then ring-closing, diisocyanate and dicarboxylic acid, tetracarboxylic dianhydride or tricarboxylic acid. Although there is a method of directly synthesizing an anhydride in the presence of a catalyst, the former method is preferable because of the high degree of polymerization and the ease of adjusting the degree of polymerization. This method will be described. The reaction is as follows.

[0022]

[Chemical 5] First, each monomer is reacted at a temperature of 100 ° C. or lower in an aprotic organic solvent as described above. That is, the amide corresponding to the structural formula A is synthesized by the reaction of the diamine and the diacid chloride, and the amic acid corresponding to the structural formula B is synthesized by the reaction of the diamine and the tetracarboxylic dianhydride to form a film-forming dope. The other one is as described in (1), in which a film is formed by adding amines such as pyridine and β-picoline as a catalyst for chemically ring-closing the amic acid during or after the polymerization and acetic anhydride, butyric anhydride as a dehydrating agent. There is a method of using it as a dope. There is no problem in forming a film with either polyamidoamidic acid or polyamidoimide, but when the solubility of polyamidoimide is poor, it is preferable to form the film from polyamidoamidic acid. The order of addition of monomers at the time of polymerization is not particularly limited, but as a method for easily increasing the degree of polymerization, a diamine is dissolved in an aprotic organic solvent, and then tetracarboxylic dianhydride and diacid chloride are added. Preferably. The structure of the polymer changes depending on which of tetracarboxylic dianhydride and diacid chloride is added first, but in either case, there is no problem in achieving the object of the present invention. If the reaction temperature exceeds 100 ° C., the degree of polymerization is difficult to increase, which is not preferable. As the aprotic organic solvent used in the reaction, N-methyl-2-pyrrolidone, N, N '
-Dimethylacetamide, N-ethyl-2-pyrrolidone, N, N'-dimethylformamide, hexamethylphosphoric triamide, tetramethylurea, dimethylsulfoxide and the like can be mentioned. Among these, general-purpose solvents such as acetone, methanol, ethanol, dioxane, methyl ethyl ketone, and toluene can be used within the scope of the object of the present invention. In addition, the reaction of the above diamine and diacid chloride produces highly corrosive hydrogen chloride as a by-product of the polymerization, which is an inorganic alkali or organic epoxide or amine because it corrodes the equipment or deteriorates the pot life of the dope. It is preferable to neutralize by the above to obtain a dope for film formation. Examples of the inorganic alkali include lithium carbonate, lithium hydroxide, calcium carbonate, calcium hydroxide, magnesium carbonate and the like, epoxides such as ethylene oxide, propylene oxide and epichlorohydrin, and amines such as triethylamine, pyridine and ethanolamines. It is also preferable to use these in combination. Alternatively, without using these neutralizing agents, the polymer solution after polymerization is reprecipitated with a large amount of an aqueous poor solvent to separate the polymer, which is then dried and dissolved again in an aprotic organic solvent to form a dope for film formation. It is also possible to Inorganic salts such as lithium chloride, calcium chloride, magnesium chloride, lithium bromide and calcium bromide may be added to these film forming dopes to improve solubility and stability. An appropriate amount of the inorganic salt added is 1 to 200% by weight based on the polymer.

The intrinsic viscosity of the dope thus obtained is preferably 0.5 to 8.0 dl / g, more preferably 1.0 to 6.0 dl / g, and even more preferably 1.2. ~ 5.0 dl / g. Intrinsic viscosity is 0.5d
If it is less than 1 / g, the resulting film has poor mechanical properties and cannot be put to practical use. On the other hand, if it exceeds 8.0 dl / g, the viscosity of the dope is abnormally high, and gel elasticity is imparted, which results in uneven casting at the time of discharging from the die during film formation and in productivity, which is not preferable. The polymer concentration of the dope is preferably 1 to 50% by weight, more preferably 3 to 30% by weight.
If it is less than 1% by weight, the productivity is reduced and the discharge unevenness in the die is
When it exceeds 50% by weight, the viscosity is remarkably increased, which causes a melt fracture in the die and an abnormal increase in extrusion pressure, which becomes a problem. The viscosity of the dope is 10 to 20000 at 30 ° C.
Poise, preferably 50 to 10,000 poise. 1
If the porosity is less than 0 poise, the casting unevenness in the spinneret exceeds 20,000 poise, and melt fracture occurs, which is not preferable. The intrinsic viscosity, polymer concentration, and viscosity have been explained above, but since these three are in a functional relationship with each other, when the optimum intrinsic viscosity is determined, the latter two have properties that are naturally determined unless the temperature is changed. Is.

Within the scope of the object of the present invention, an inorganic or organic additive such as a lubricant, an antioxidant, an anti-UV agent or an antistatic agent may be added to the dope.
For example, the lubricant is inorganic particles composed of oxides, nitrides, carbides, salts or simple elements of transition metal elements II, III and IV of the Periodic Table of Elements. Specifically, MgO, Zn
O, Al ₂ O ₃ , SiO ₂ , TiO ₂ , TiN, Zr
N, SiC, MgCO ₃ , CaCO ₃ , Cu, Ag, A
Examples include u, Zn, Al, Co, Ni and carbon black. It is also preferable to add an organic lubricant because the affinity with the aromatic polyamideimide film of the present invention is improved.

The production method of the film forming dope in the present invention has been described above. Next, the production method of the film will be described.

The dope can be formed into a film by a wet method, a dry method, or a dry-wet method. In particular, the wet method is a method for producing the aromatic polyamideimide film of the present invention with an extremely high Young's modulus and at a low cost. Is particularly preferable as

When the film is formed by the wet method, the dope is extruded from the die and introduced into the wet bath. Typical examples thereof include the following methods.

A method of immersing the die in a wet bath and extruding the dope directly into the bath.

A method of introducing a dope extruded from a die into a wet bath through an air layer.

A method in which the dope extruded from the die is cast onto a support such as a drum, and the support is immersed in a wet bath to peel the film from the support.

This bath is generally composed of an aqueous medium and may contain, in addition to water, a water-soluble organic solvent such as alcohol, glycol, ketone or amide, or an inorganic salt. However, the water content is generally 30% or more, preferably 50% or more, and the bath temperature is usually 0 to 100 ° C. As a method like this,
For example, as already known in Japanese Examined Patent Publication No. 1-444143,
In this case, the polymer of the aromatic polyamide composition, the amide solvent and the inorganic salt are adjusted within a certain range, and the amide solvent is present in the wet bath and biaxially stretched 1.5 times or more,
There is provided a method for improving mechanical properties and electrical properties by subjecting the stretched film to a heat treatment in a state of containing 1% by weight or more of an amide solvent. Since it is coagulated directly in a wet bath, the replacement speed of the amide solvent and the aqueous medium is extremely high, so that numerous voids occur on the film surface, causing devitrification and skin-core formation. The film is very brittle and has a poor surface condition, so it has not been practically used. However, in the wet film formation using the aromatic polyamideimide of the present invention, the reason is not clear,
Probably because the substitution rate of the solvent is controlled by the inclusion of amic acid or imide, it is a film with excellent mechanical properties, heat / humidity properties, and transparency even without the above complicated condition settings. There is a feature that can be easily obtained.

Which of the above-mentioned methods (1) to (4) can be applied can be appropriately determined depending on the kind, concentration, viscosity, etc. of the aromatic polyamideimide type. Generally, in the case of low viscosity, the method of high viscosity is used. In the case of, the method of is advantageous. The other method can be suitably adopted regardless of whether the viscosity is low or high. The feature of this method is that in the wet film forming method, the dope extruded from the die is directly introduced into an aqueous medium to form a film, so that a die line is generated in the extruding direction and remains as a vertical line on the film. This is particularly noticeable when a highly viscous dope is used, and this may cause a problem depending on the application. In order to prevent the generation of the vertical stripes, it can be introduced into the wet bath after once casting on the support to eliminate the vertical stripes. This support is made of a drum, roll, belt or the like, and the material is metal, glass, plastic, rubber or the like. The temperature of the support can be raised, and the temperature is preferably from room temperature to about 200 ° C. The film introduced into the wet bath by-is desalted and desolvated in the bath and at the same time stretched 0.9 to 2.0 times in the longitudinal direction, dried at 200 to 500 ° C. in a tenter or the like, and heat-treated. At the same time, the film is stretched 0.9 to 2.0 times in the transverse direction to form the final film.

When the film is formed by a dry method or a dry-wet method, the dope is cast from a spinneret onto a suitable support such as a roll or a belt. The material and shape of the support are not particularly limited, but glass and metal are generally suitable.
Such a support is preferable from the viewpoint of film forming property when it is heated and held at a temperature of the solvent boiling point + 100 ° C. or lower and the dope temperature or higher. In addition to the above, as a casting method, there are a roll coating method, a knife coating method, a method using an applicator, and a method combining these.

The cast dope is then fed to a dry process to evaporate the solvent under heating to render it self-supporting. In this case, it is necessary to adjust so that the solvent does not evaporate rapidly from the film surface. Usually, the treatment is carried out at a temperature not lower than room temperature and a temperature not higher than the boiling point of the solvent + 100 ° C., but it may be carried out in a temperature range not significantly exceeding the boiling point of the solvent under an atmosphere of reduced pressure to normal pressure, and is generally room temperature to 300 ° C. A uniform film becomes more difficult as the film thickness increases, but in such a case, it can be improved by decreasing the solvent evaporation rate.
That is, it may be dried at a low temperature for a long time.

The film which has undergone the dry process is peeled from the support, and when a non-evaporated substance such as an inorganic salt or a substance which accelerates the decomposition of the film is not added to the dope, the film is subjected to a heat treatment process without a wet process. It is also possible to supply it to the final film to obtain the final film, but there is no problem even if a wet process is performed. The dope containing an inorganic salt or the like is supplied to a wet process to remove them. The wet bath has the same composition as that of the wet film-forming bath, and the same applies to the case where a water-soluble organic solvent, an inorganic salt or the like is further added to adjust the desalination rate in the desalting operation. . The desalination rate depends on the bath temperature, and the higher the temperature, the faster the temperature is usually from room temperature to 10
Perform at 0 ° C. In this wet process, the peeled film is stretched 0.9 to 2.0 times in the machine direction in the bath.

The film that has undergone the wet process is dried and heat-treated in a tenter or the like, and at the same time, the film width is 0.9 to 0.9.
The final film is stretched 2.0 times.

The film thus obtained is an extremely uniform film having excellent transparency and no voids.

In order to carry out the above-mentioned film formation in a laboratory, after casting the dope on a support such as a glass plate or a metal plate, the solvent is evaporated with the support in the wet method or in a hot air oven in the dry-wet method. After it has self-supporting property, the film alone or fixed to a frame and immersed in a wet bath to remove solvent and inorganic salt, and then stretched as necessary to dry water and heat-treat A film is obtained.

[0039]

[Measurement Method of Characteristic Value] The characteristic value of the present invention is based on the following measuring method.

(1) Young's modulus, elongation at break, breaking strength At 25 ° C. and 65% RH, the film was set with a “tensilon” type tensile tester so that the test width was 10 mm and the test length was 50 mm, and the tensile speed was set. Tensile measurement was performed at 300 mm / min.

(2) Moisture absorption rate The film was cut into about 150 mm x 150 mm and
It is dried in an oven at 0 ° C. for 1 hour, then cooled in phosphorus pentoxide and weighed. This was allowed to stand in a humidity of 75% for 48 hours, and the weight was measured and calculated from the following formula.

Moisture absorption rate = [(weight after leaving-weight at absolute dryness) /
Dry weight] x 100 (%)

(3) Heat Shrinkage The film is cut into a width of 10 mm and a test length of 250 mm, and a length of 200 mm is accurately measured and marked in advance. The sample is hung in an oven set at 250 ° C. under substantially no load and left for 10 minutes. Remove sample, cool to room temperature, and distance L between marks
(Mm) was measured and calculated from the following formula from the difference from the original size.

Thermal shrinkage = [(200−L) / 200] × 100 (%)

(4) Density The value of only the film was measured at 25 ° C. by a heptane-carbon tetrachloride type density gradient tube.

(5) Solution Viscosity The value measured at a temperature of 25 ° C. using a B-type viscometer manufactured by Tokyo Keiki Co., Ltd. is shown.

(6) Intrinsic viscosity Using an Ubbelohde viscometer, N-methyl-2-pyrrolidone (hereinafter NMP) containing 2.5% by weight of lithium bromide was used.
(Omitted) Dissolve 0.5 g of polymer in 100 ml and
Intrinsic viscosity calculated at the following formula at 0 ° C. = ln (t / t ₀ ) /0.5 (dl / g) t ₀ : Solvent flow down time (sec) t: Solution flow down time (sec)

[0048]

【Example】

Example 1 100 N of dried NMP was put into a 200 L kneader, and paraphenylenediamine (hereinafter abbreviated as PPDA) was added thereto.
06 kg (46.77 mol) and 1,3-bis (3-aminophenoxy) benzene 2.41 kg (8.24 mol)
Was dissolved under stirring and cooled to 5 ° C. Pyromellitic dianhydride (hereinafter abbreviated as PMDA) 0.56 kg (2.5
7 mol) was charged as a powder and reacted for about 15 minutes. Into this, 12.45 kg (52.43 mol) of 2-chloroterephthalic acid chloride (hereinafter abbreviated as CTPC) was added over 20 minutes. After 15 minutes, the viscosity suddenly increased, so N
Dilute with MP and continue stirring for 45 minutes. Then, 100 mol% of propylene oxide was added to the generated hydrogen chloride and neutralized at 30 ° C. for 1 hour. The obtained dope had a polymer concentration of 9.5%, an intrinsic viscosity of 3.0 dl / g and a viscosity of 210.
It was 0 poise. This dope is divided into two, one is used as it is for the film-forming, and the other is β-picoline (0.5 times mol of the charged PMDA) and acetic anhydride (4 times the mol of charged PMDA) as a chemical ring-closing agent. Add 3 more
The mixture was stirred for 0 minutes to obtain a dope for film formation. These two types of dope were extruded from the die and directly introduced into a water tank to remove the solvent. Supply the film from the water tank to the tenter and 300 ℃
Drying and heat treatment were carried out at the temperature of 1 minute for 2 minutes to obtain two final films. The characteristics of this film are shown in Table 1.

Example 2 Dry NMP was added to a 500 ml four-necked flask in an amount of 211 m.
Into this, 14.26 g (0.1 mol) of 2-chloroparaphenylenediamine (hereinafter abbreviated as CPA) was dissolved under stirring and cooled to 10 ° C. In this, 3, 4, 3 ',
4'-biphenyltetracarboxylic dianhydride (hereinafter BP
1.47 g (0.005 mol) of DA) was charged as powder and reacted for 20 minutes. Isophthalic chloride (hereinafter abbreviated as IPC) 2.03 g (0.01 mol) powder was added to this as it was and reacted for 15 minutes.
19 g (0.085 mol) was added with a dropping funnel over 20 minutes. After 15 minutes, the viscosity increased, so the solution was diluted with NMP, and the polymerization was completed over a further 45 minutes. After that, lithium carbonate was added to the generated hydrogen chloride in an amount of 96 mol% to obtain 5
Neutralized at 0 ° C. for 2 hours. The obtained dope had a polymer concentration of 8.9%, an intrinsic viscosity of 3.2 dl / g and a viscosity of 2650 poise. Extract half of this dope and add β-picoline and acetic anhydride as chemical ring closure agents to the remaining dope.
The mixture was stirred for 0 minutes to obtain two types of dope for film formation. The unclosed dope was cast on a mirror-finished SUS (stainless steel) 306 plate with an applicator, and the solvent was dried for 8 minutes in a safety oven heated to 150 ° C. After drying, remove the film from the SUS plate, fix it on a metal frame, put the frame together in running water at 30 ° C, immerse it for 30 minutes, desalt and desolventize, wipe off the water on the film surface, 300 ° C
Was dehydrated and heat-treated for 1 minute in the hot air oven. On the other hand, the chemically closed dope was cast on a SUS plate and immersed together with the SUS plate in running water for 15 minutes. This film was fixed on a metal frame and subjected to the same treatment as described above. Table 1 shows the characteristics of the film
It was shown to.

Example 3 Dry NMP274m in a 500 ml four-necked flask.
Into this, 21.39 g (0.15 mol) of CPA was dissolved with stirring and cooled to 5 ° C. PM in this
0.49 g (0.0022 mol) of DA was added and reacted for 15 minutes, followed by 1.53 g of IPC (0.0075 mol).
In addition, it reacted for 20 minutes. Furthermore, in this, CTPC32.
88 g (0.1384 mol) was added dividedly so that the internal temperature did not exceed 30 ° C. The reaction was completed over 1 hour after the addition was completed. Then, 100 mol% of propylene oxide was added to the generated hydrogen chloride, and the mixture was neutralized for 2 hours. The obtained dope had a polymer concentration of 11.4% and an intrinsic viscosity of 3.2 g /
dl, viscosity 4700 poise. This dope was cast on a glass plate using an applicator and immersed in running water at 30 ° C. for 30 minutes. The same operation was performed to make two wet films. One piece is fixed to the frame and 300 ℃
And dried and heat treated for 1 minute. The remaining one sheet was washed with water, drawn 1.2 times in one direction, and then treated in the same manner. To the remaining dope, β-picoline and acetic anhydride were added as chemical ring-closing agents, stirred at 70 ° C. for 1 hour, cooled to room temperature, cast on a glass plate with an applicator, and the whole glass plate was placed in running water for 3 hours.
It was immersed for 0 minutes. This film was fixed to a metal frame and treated in the same manner as above. The properties of these films are shown in Table 1.

Example 4 Dry NMP 214m in a 500 ml four-necked flask.
Into this, 17.11 g (0.12 mol) of CPA was dissolved under stirring and cooled to 10 ° C. IP in this
8.53 g (0.042 mol) of C was added and reacted for 30 minutes. Further, 18.52 g (0.078 mol) of CTPC was added by a dropping funnel over 15 minutes. After 1 hour, the reaction solution became extremely high in viscosity and completed the polymerization. 100 mol% of propylene oxide was added to the hydrogen chloride generated therein to neutralize for 1 hour. The obtained dope has a polymer concentration of 1
The viscosity was 0.8%, the intrinsic viscosity was 2.98 dl / g, and the viscosity was 2200 poise. This dope is SUS with an applicator
Cast on a plate, immerse in water at 0 ° C for 5 minutes, desolvate in running water at 30 ° C for 5 minutes, then fix to a metal frame,
It was treated in a hot air oven at 300 ° C. for 1 minute. The characteristics of the film are shown in Table 1.

Comparative Example 1 Dry NMP251m in a 500 ml four-necked flask.
1 was charged, and 24.02 g (0.12 mol) of 4,4'-diaminodiphenyl ether was dissolved in the solution under stirring and cooled to 3 ° C. In this, 3.53 g (0.0
(12 mol) was added as a powder and reacted for 20 minutes. Further, 25.65 g (0.108 mol) of CTPC was added thereto by a dropping funnel over 15 minutes. One hour after the addition was completed, the viscosity became high and the polymerization was completed. 100 mol% of propylene oxide was added as a neutralizing agent to the generated hydrogen chloride. The obtained dope has a polymer concentration of 12.5% and an intrinsic viscosity of 2.6.
It was dl / g and the viscosity was 2100 poise. This dope was cast on two glass plates using an applicator, and one of the glass plates was immersed in running water at 30 ° C. for 15 minutes to remove the solvent. The two films taken out from the water tank were fixed to a metal frame and treated in a hot air oven at 300 ° C for 1 minute. The characteristics of the film are shown in Table 1.

Comparative Example 2 17.11 g CPA in a 500 ml four-necked flask.
(0.12 mol) and 233 ml of dried NMP were added and cooled to 10 ° C. PMDA23.56g in this
(0.108 mol) was added and stirred for 1 hour. CTPC
2.56 g (0.0108 mol) was added, and the reaction was further performed for 1 hour. The dope became very viscous. Hydrogen chloride generated in the reaction was neutralized with PO. The polymer concentration of the obtained dope was 12.3%, the intrinsic viscosity was 2.6 dl / g, and the viscosity was 2200 poise. This dope is cast onto two glass plates, one is immersed in running water at 30 ° C to remove the solvent, and the other one is dried in a safety oven at 150 ° C for 7 minutes, and the glass plates together with running water. And the solvent was removed. Fix the two films taken out of the water tank to the metal frame,
It was treated in a hot air oven at 280 ° C. for 1.5 minutes. The characteristics of the film are shown in Table 1.

[0054]

[Table 1]

[0055]

INDUSTRIAL APPLICABILITY The present invention is a film having a structure mainly composed of amide bonds, and can have mechanical properties, humidity properties and heat resistance which have not been found in conventional aramid films. Especially, when an imide bond is introduced into the molecular chain, the effect is remarkable. When this film is formed by a wet method, the effect is further exhibited, and therefore it is very effective for cost reduction due to improvement in productivity.

The film having the above characteristics is most suitable as a base film for a magnetic recording medium, particularly a thin film type base film for magnetic recording. In addition, it can be widely used as a base film for flexible printed circuit boards, for thermal transfer, for electrical insulation, etc.

Claims (1)

[Claims] 1. 60 mol% or more of repeating units are represented by: The aromatic polyamideimide film, wherein n: m is a molar ratio of 100: 0 to 30:70 (wherein R ₁ , R ₂ , and R ₃ are benzene, naphthalene, anthracene, and biphenyl rings). And two or more of these may be contained, and each ring may have a substituent.).