JP6043443B2 - Copolyamideimide film - Google Patents

Description

  The present invention relates to a copolymerized polyamideimide film.

Polyimide films have excellent thermal and mechanical properties, and recently, as the demand for high temperature materials has increased, the need for their use has emerged. However, the use of polyimide film is limited due to its high price.
In particular, recently, not only optical characteristics but also thermal
The need for polyimide films with excellent mechanical properties is emerging.

Therefore, as the demand for cheaper polyimide films with superior thermal, mechanical and optical properties increases, attempts have been made to mix or copolymerize polyamides with polyimide, the main material of polyimide films. Yes.

However, a copolymerized polyamideimide film that satisfies the optical characteristics as well as the thermal and mechanical characteristics required in the market has not yet been provided.

Therefore, the present invention has been made to solve the above-described problems, and its purpose is to provide a copolymerized polyamideimide film having excellent thermal, mechanical and optical properties, and a method for producing the copolymerized polyamideimide. It is to provide.

In order to achieve the above object, according to one aspect of the present invention, TFDB (2,2′-bis trifluo
A unit structure derived from romethyl-4,4'-biphenyl diamine), 6FDA (4,4 '-(hexa-fluoroi
unit structure derived from sopropylidene) diphthalic anhydride) and TPC (Terephthaloy)
The present invention provides a copolymerized polyamideimide film comprising a resin having a unit structure derived from l chloride; 1,4-benzenedicarbonyl chloride).

According to another aspect of the present invention, TFDB and 6FDA are reacted in solution to obtain a first polymer,
A method for producing a copolymerized polyamideimide, comprising: a step of producing a polyamic acid by solution reaction of the first polymer and TPC; and a step of imidizing the polyamic acid in the presence of an imidization catalyst. I will provide a.

The present invention provides a copolymerized polyamideimide film having excellent thermal, mechanical and optical properties,
And a method for producing a copolymerized polyamideimide.

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description with reference to the accompanying drawings.
It is a graph which shows the GPC-RI analysis result of the copolymerization polyamideimide which concerns on the Example of this invention.

The copolymerized polyamideimide film according to the present invention has TFDB (2,2'-bis trifluorometh).
Unit structure derived from yl-4,4'-biphenyl diamine), 6FDA (4,4 '-(hexa-fluoroisoprop
unit structure derived from ylidene) diphthalic anhydride) and TPC (Terephthaloyl chlo
ride; a unit structure derived from 1,4-benzenedicarbonyl chloride) is copolymerized, and the copolymerized resin has a weight average molecular weight of 10,000 to 400,000.

That is, the copolymerized polyamideimide film according to the present invention is a polyamide component,
A unit structure derived from TFDB and a unit structure derived from TPC are polymerized, and as a polyimide component, a unit structure derived from TFDB and a unit structure derived from 6FDA are polymerized. In the copolymerized polyamideimide film of the present invention, both the polyamide component and the polyimide component contain TFDB as a diamine unit structure. By realizing the high glass transition temperature, excellent optical properties and high solubility of the polyimide component formed thereby, and simultaneously realizing the low thermal expansion coefficient and high mechanical properties of the polyamide component formed thereby A transparent and highly heat-resistant film can be produced.

The polyamide component and the polyimide component are copolymerized with each other, so that the excellent thermal and mechanical properties of the polyimide component and the excellent optical properties of the polyamide component are combined without being separated. The characteristics can be expressed as a copolymer.

Here, the copolymerized resin has a unit structure derived from TFDB: a unit structure derived from 6FDA: a unit structure derived from TPC of 1: 0.2 to 0.8: 0.8 to 0.2. By copolymerizing at a molar ratio, the respective properties of the polyamide component and the polyimide component can be significantly expressed. More preferably, the unit structure derived from TFDB: the unit structure derived from 6FDA: the unit structure derived from TPC is 1: 0.3 to 0.7: 0.
By copolymerizing at a molar ratio of 3 to 0.7, the optical characteristics of the polyamide component and the thermal and mechanical characteristics of the polyimide component can be optimized.

When the molar ratio of the unit structure derived from TPC is smaller than 0.2, the degree of improvement in heat resistance is insignificant, and it is difficult to express the properties of the polyamide component. When the molar ratio of the unit structure derived from TPC is greater than 0.8, it may be difficult to produce a material that achieves uniform physical properties because it is difficult to control the degree of polymerization during copolymerization of the unit structure. . And
When the molar ratio of the unit structure derived from TPC is 0.3 to 0.7, the physical characteristics of the polyamide component and the physical characteristics of the polyimide component are uniformly expressed, and appropriate thermal, mechanical and optical properties are obtained. Characteristics.

The method for producing a copolymerized polyamideimide according to the present invention includes a step of producing a polyamic acid by reacting a solution of TFDB and 6FDA to obtain a first polymer, and reacting the first polymer with TPC. And an imidization reaction of the polyamic acid in the presence of an imidization catalyst.

That is, in the method for producing a copolymerized polyamideimide according to the present invention, in the step of producing polyamic acid, TFDB and 6FDA are subjected to solution reaction to polymerize a polyimide component, and then TPC is added to polymerize the polyamide component. . That is, after first polymerizing a polyimide component, the polymerized polyimide component is copolymerized with a polyamide component.
When the polyamide component is polymerized first, the viscosity of the polymerized polyamide component increases so rapidly that the reaction with the polyimide component added later may not occur uniformly. Since the solubility of the polyamide component is relatively inferior to the solubility of the polyimide component, a white turbidity phenomenon of the produced polyamic acid solution may occur and phase separation from the solvent may occur. Therefore, it is advantageous to polymerize the polyimide component first.

In the polyamic acid production process, the solution reaction of the TFDB and 6FDA is TFDB:
6FDA is carried out at a molar ratio of 100 mol%: X mol%, and the solution reaction of the first polymer and TPC is carried out by the first polymer: TPC being 100 mol%: 100-X mol% (X is 20-8).
0, preferably 30 to 70).
Here, in the imidization step of polyamic acid, the imidation catalyst can be used as long as it is a commonly used imidization catalyst, and pyridine and acetic anhydride can be used simultaneously.

The copolymerized polyamideimide film according to the present invention can be produced by a normal polyimide film production method using the copolymerized polyamideimide produced by the above-described method for producing a copolymerized polyamideimide of the present invention.

Hereinafter, the present invention will be described in detail with reference to the following examples. Here, these examples are for explaining the present invention, and do not limit the scope of the present invention.

<Example 1>
Production of copolymerized polyamideimide Charged 812 g of N, N-dimethylacetamide (DMAc) while passing nitrogen through a 1.5 L reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and condenser. Then, after adjusting the temperature of the reactor to 25 ° C., 64.046 g (0.2 mol) of TFDB was dissolved in DMAc to obtain a first solution, and the first solution was maintained at 25 ° C. 6FD in the first solution
Add 71.08 g (0.16 mol) of A and stir for 1 hour to dissolve and react.
A solution was obtained. At this time, the temperature of the second solution was maintained at 25 ° C. Then TPC 8.1208
g (0.04 mol) was added to the second solution to obtain a polyamic acid solution having a solid concentration of 15% by weight.

The polyamic acid solution was stirred at room temperature for 2 hours, and 27.8 g of pyridine and acetic anhydride 35 were stirred.
. After 9 g was added to the stirred polyamic acid solution and stirred for 30 minutes, it was further heated at 80 ° C. for 1 minute.
Stir for hours and cool to room temperature. Subsequently, the resulting solution is gradually put into a container containing 20 L of methanol and precipitated. Finally, the precipitated solid is filtered and pulverized, then 10
It was dried in vacuum at 0 ° C. for 6 hours to obtain 128 g of a solid polyamide powder copolymer polyamideimide.

When the weight average molecular weight of the copolymerized polyamideimide thus obtained was measured, the weight average molecular weight was 170,000. FIG. 1 is a graph showing a GPC-RI analysis result of a copolymerized polyamideimide according to an example of the present invention. Referring to FIG. 1, (4) of the graph of FIG.
From the fact that a single peak appears as represented by (), it can be seen that it was synthesized as a copolymer.

Production of copolymerized polyamideimide film The above-mentioned 128 g of solid powdered copolymerized polyamideimide was dissolved in 512 g of N, N-dimethylacetamide (DMAc) to obtain a 20 wt% solution. After the solution thus obtained was applied to a stainless steel plate, it was cast to a thickness of 700 μm and heated with hot air at 130 ° C. for 30 minutes.
A film was formed by drying for a minute. Then, this film was peeled from the stainless steel plate and fixed to the frame with pins. Place the frame with the film fixed in a vacuum oven.
After slowly heating from 0 ° C. to 300 ° C. for 2 hours, the film was gradually cooled to separate the film from the frame to obtain a copolymerized polyamideimide film. Then, the obtained copolymer polyamideimide film was heat-treated at 300 ° C. for 30 minutes (thickness: 100 μm).

<Example 2>
Preparation of copolymerized polyamideimide The reactor of Example 1 was charged with 785 g of N, N-dimethylacetamide (DMAc), the reactor temperature was adjusted to 25 ° C., and 64.046 g (0.2 mol) of TFDB was added to DMAc. A first solution was obtained by dissolution, and the temperature of the first solution was maintained at 25 ° C. Add 6FD to this first solution
62.195 g (0.14 mol) of A was added and stirred for 1 hour to dissolve and react to obtain a second solution. At this time, the temperature of the second solution was maintained at 25 ° C. Then, TPC is added to the second solution.
12.1812 g (0.06 mol) was added to obtain a polyamic acid solution having a solid concentration of 15% by weight.

The polyamic acid solution was stirred at room temperature for 8 hours, 25 g of pyridine and 32 g of acetic anhydride were added to the stirred polyamic acid solution, stirred for 30 minutes, and further stirred at 80 ° C. for 1 hour to cool to room temperature. After gradually putting it into a container containing 20 L of methanol and precipitating it, the precipitated solid content was filtered and pulverized, and then dried at 100 ° C. in vacuum for 6 hours to obtain 124 g of a solid polyamide powder copolymer polyamideimide. .

When the weight average molecular weight of the copolymerized polyamideimide thus obtained was measured, the weight average molecular weight was 200,000.

Production of Copolymer Polyamideimide Film The above-mentioned 124 g of solid powder copolymer polyamidoimide was dissolved in 496 g of N, N-dimethylacetamide (DMAc) to obtain a 20 wt% solution.
Thereafter, a copolymerized polyamideimide film was produced in the same manner as in Example 1 using this solution.

<Example 3>
Production of copolymerized polyamideimide The reactor of Example 1 was charged with 753 g of N, N-dimethylacetamide (DMAc), the reactor temperature was adjusted to 25 ° C, and then 64.046 g (0.2 mol) of TFDB. ) Was dissolved in DMAc to obtain a first solution, which was maintained at 25 ° C. 6FDA53.3 in the first solution
1 g (0.12 mol) was added and stirred for 1 hour to dissolve and react to obtain a second solution. At this time, the temperature of the second solution was maintained at 25 ° C. Then, TPC 16.241 is added to the second solution.
6 g (0.08 mol) was added to obtain a polyamic acid solution having a solid concentration of 15% by weight.

The polyamic acid solution was stirred at room temperature for 8 hours, 21 g of pyridine and 27 g of acetic anhydride were added to the stirred polyamic acid solution and stirred for 30 minutes, and further stirred at 80 ° C. for 1 hour to cool to room temperature. After gradually putting it into a container containing 20 L of methanol and precipitating, the precipitated solid content was filtered and pulverized, and then dried at 100 ° C. in vacuum for 6 hours to obtain 120 g of a solid polyamide powder copolymer polyamideimide. .

When the weight average molecular weight of the copolymerized polyamideimide thus obtained was measured, the weight average molecular weight was 251,000. FIG. 1 is a graph showing a GPC-RI analysis result of a copolymerized polyamideimide according to an example of the present invention. Referring to FIG. 1, the graph of FIG.
From the fact that a single peak appears as represented by (), it can be seen that it was synthesized as a copolymer.

Production of Copolymer Polyamideimide Film 120 g of the solid powder copolymer polyamideimide was dissolved in 480 g of N, N-dimethylacetamide (DMAc) to obtain a 20 wt% solution.
Thereafter, a copolymerized polyamideimide film was produced in the same manner as in Example 1 using this solution.

<Example 4>
Preparation of copolymerized polyamideimide The reactor of Example 1 was charged with 725 g of N, N-dimethylacetamide (DMAc), and the temperature of the reactor was adjusted to 25 ° C, and then 64.046 g (0.2 mol) of TFDB. ) Was dissolved in DMAc to obtain a first solution, which was maintained at 25 ° C. 6FDA44.4 in the first solution
25 g (0.1 mol) was added and stirred for 1 hour to dissolve and react to obtain a second solution. At this time, the temperature of the second solution was maintained at 25 ° C. Then, 20.3 g of TPC (
0.10 mol) was added to obtain a polyamic acid solution having a solid content concentration of 15% by weight.

The polyamic acid solution was stirred at room temperature for 8 hours, and 17.4 g of pyridine and acetic anhydride 22 were obtained.
. 5 g was added to the stirred polyamic acid solution and stirred for 30 minutes, and then further at 80 ° C.
After stirring for a period of time and cooling to room temperature, this is gradually put into a container containing 20 L of methanol and precipitated. The precipitated solid is filtered and pulverized, then dried at 100 ° C. in vacuum for 6 hours and 115.
g of copolyamideimide of solid powder was obtained.
The weight average molecular weight of the copolymerized polyamideimide thus obtained was measured and found to be 250,000.

Production of Copolymer Polyamideimide Film The above 115 g of solid powder copolymer polyamidoimide was dissolved in 460 g of N, N-dimethylacetamide (DMAc) to obtain a 20 wt% solution.
Thereafter, a copolymerized polyamideimide film was produced in the same manner as in Example 1 using this solution.

<Example 5>
Preparation of copolymerized polyamideimide The reactor of Example 1 was charged with 703 g of N, N-dimethylacetamide (DMAc), the reactor temperature was adjusted to 25 ° C., and 64.046 g (0.2 mol) of TFDB was then added to DMAc.
To obtain a first solution, which was maintained at 25 ° C. 6FDA35.
54 g (0.08 mol) was added and stirred for 1 hour to dissolve and react to obtain a second solution. At this time, the temperature of the second solution was maintained at 25 ° C. Then, TPC24.36 is added to the second solution.
g (0.12 mol) was added to obtain a polyamic acid solution having a solid concentration of 15% by weight.

The polyamic acid solution was stirred at room temperature for 8 hours, and 14 g of pyridine and 18 g of acetic anhydride were added to the stirred polyamic acid solution, stirred for 30 minutes, and further stirred at 80 ° C. for 1 hour to cool to room temperature. Gradually put into a container containing 20 L of methanol to cause precipitation, and the precipitated solid content was filtered and pulverized, and then dried at 100 ° C. in vacuum for 6 hours to obtain 111 g of solid polyamide powder copolymer polyamideimide. .

When the weight average molecular weight of the copolymerized polyamideimide thus obtained was measured, the weight average molecular weight was 253,400. FIG. 1 is a graph showing a GPC-RI analysis result of a copolymerized polyamideimide according to an example of the present invention. Referring to FIG. 1, (2) of the graph of FIG.
From the fact that a single peak appears as represented by (), it can be seen that it was synthesized as a copolymer.

Production of Copolymer Polyamideimide Film The above-mentioned 111 g of solid powdery copolymer polyamideimide was dissolved in 444 g of N, N-dimethylacetamide (DMAc) to obtain a 20 wt% solution.
Thereafter, a copolymerized polyamideimide film was produced in the same manner as in Example 1 using this solution.

<Example 6>
Preparation of copolymerized polyamideimide The reactor of Example 1 was charged with 675 g of N, N-dimethylacetamide (DMAc), the reactor temperature was adjusted to 25 ° C., and then 64.046 g (0.2 mol) of TFDB was added to DMAc.
To obtain a first solution, which was maintained at 25 ° C. 6FDA 26. in the first solution.
655 g (0.06 mol) was added and stirred for 1 hour to dissolve and react to obtain a second solution. At this time, the temperature of the second solution was maintained at 25 ° C. Then, TPC28.4 is added to the second solution.
2 g (0.14 mol) was added to obtain a polyamic acid solution having a solid content concentration of 15% by weight.

The polyamic acid solution was stirred at room temperature for 8 hours, and 11 g of pyridine and 13.5 acetic anhydride were stirred.
g was added to the stirred polyamic acid solution and stirred for 30 minutes, further stirred at 80 ° C. for 1 hour and cooled to room temperature, and this was gradually put into a container containing 20 L of methanol to cause precipitation.
The precipitated solid content was filtered and pulverized, and then dried in vacuum at 100 ° C. for 6 hours to obtain 107 g of a solid polyamide powder copolymer polyamideimide.

The weight average molecular weight of the copolymerized polyamideimide thus obtained was measured and found to be 310,000. FIG. 1 is a graph showing a GPC-RI analysis result of a copolymerized polyamideimide according to an example of the present invention. Referring to FIG. 1, (1) of the graph of FIG.
From the fact that a single peak appears as represented by (), it can be seen that it was synthesized as a copolymer.

Preparation of Copolymer Polyamideimide Film The 107 g of the solid powder of copolymer polyamideimide was dissolved in 428 g of N, N-dimethylacetamide (DMAc) to obtain a 20 wt% solution.
Thereafter, a copolymerized polyamideimide film was produced in the same manner as in Example 1 using this solution.

<Example 7>
Preparation of copolymerized polyamideimide The reactor of Example 1 was charged with 648 g of N, N-dimethylacetamide (DMAc), the reactor temperature was adjusted to 25 ° C., and then 64.046 g (0.2 mol) of TFDB was added to DMAc.
To obtain a first solution, which was maintained at 25 ° C. 6FDA in the first solution 17.
77 g (0.04 mol) was added and stirred for 1 hour to dissolve and react to obtain a second solution. At this time, the temperature of the second solution was maintained at 25 ° C. Then, TPC 32.48 was added to the second solution.
g (0.16 mol) was added to obtain a polyamic acid solution having a solid concentration of 15% by weight.

The polyamic acid solution was stirred at room temperature for 8 hours, 21 g of pyridine and 27 g of acetic anhydride were added to the stirred polyamic acid solution and stirred for 30 minutes, and further stirred at 80 ° C. for 1 hour to cool to room temperature. After gradually putting it into a container containing 20 L of methanol and precipitating, the precipitated solid content was filtered and pulverized, and then dried at 100 ° C. under vacuum for 6 hours to obtain 102 g of a solid polyamide powder copolymer polyamideimide. .

When the weight average molecular weight of the copolymerized polyamideimide thus obtained was measured, the weight average molecular weight was 227,000.

Production of Copolymer Polyamideimide Film The above-mentioned 102 g of solid powder copolymer polyamidoimide was dissolved in 408 g of N, N-dimethylacetamide (DMAc) to obtain a 20 wt% solution.
Thereafter, a copolymerized polyamideimide film was produced in the same manner as in Example 1 using this solution.

<Comparative Example 1>
Polyimide production A reactor was charged with 611 g of N, N-dimethylacetamide (DMAc), and the temperature of the reactor was adjusted to 25 ° C. Then, 64.046 g (0.2 mol) of TFDB was dissolved in DMAc to dissolve the first solution. And this first solution was maintained at 25 ° C. In the first solution, 88.85 g of 6FDA (0
. 2 mol) was added to obtain a polyamic acid solution having a solid concentration of 20% by weight.

The polyamic acid solution was stirred at room temperature for 8 hours to give 31.64 g of pyridine and acetic anhydride 4
0.91 g was added to the stirred polyamic acid solution and stirred for 30 minutes, and then further 80 ° C.
The mixture is cooled to room temperature by stirring for 2 hours, gradually poured into a container containing 20 L of methanol, precipitated, filtered and pulverized, and then dried at 100 ° C. for 6 hours in vacuum.
36 g of polyimide powder was obtained.

Manufacture of polyimide film 496 g of N, N-dimethylacetamide (DMAc)
To obtain a 20 wt% solution. Then, the polyimide film was manufactured by the method similar to Example 1 using this solution.

<Comparative Example 2>
Preparation of polyamide A 2 L reactor was charged with 1203 g of N, N-dimethylacetamide (DMAc), the temperature of the reactor was adjusted to 25 ° C., and 64.046 g (0.2 mol) of TFDB was dissolved in DMAc to obtain a first solution. A solution was obtained and this first solution was maintained at 25 ° C. Then add 6FDA to the first solution.
40.6 g (0.2 mol) was added and stirred for 1 hour to dissolve and react. On this occasion,
The temperature of the solution was maintained at 25 ° C. to obtain a polyamic acid solution having a solid concentration of 8% by weight. This was gradually poured into a container containing 20 L of distilled water to cause precipitation, and the precipitated solid was filtered and pulverized, and then dried at 100 ° C. in vacuum for 6 hours to obtain 101 g of polyamide powder.

Manufacture of polyamide film The 101 g of polyamide powder was converted into 1161 g of N, N-dimethylacetamide (DMA
An 8 wt% solution was obtained by dissolving in c). Then, the polyamide film was manufactured by the method similar to Example 1 using this solution.

<Physical property evaluation method>
(1) Average transmittance Each of the films produced in the examples was subjected to UV spectroscopy (Konica Minolta, CM-370).
0D) was used to measure the average transmittance at a wavelength of 380 to 780 nm.

(2) Yellowing index (Yellow Index, YI)
The yellowing degree at a wavelength of 380 to 780 nm was measured by a UV spectrometer (manufactured by Konica Minolta, CM-3700D) according to ASTM E313 standard.

(3) Thermal expansion coefficient (CTE)
TMA (the Diamond TMA, manufactured by Perkin Elmer) was used for TMA (the
rmo-mechanical analyzer)-10 ° C / min ramp rate according to Method and 10
The coefficient of thermal expansion at 50 to 260 ° C. was measured twice under the condition of a load of 0 mN. Here, the second measurement value was presented except for the first measurement value. The reason for this is that residual stress may remain in the film due to heat treatment of the film, and therefore the second measurement value was presented as an actual measurement value after the residual stress was completely removed by the first measurement.

(4) Thickness The thickness of each film manufactured in the example is changed to Anritsu Electronic Mic.
Measured by rotometer. Here, the Anritsu Electronic
The deviation of Micrometer is 0.5% or less.

  The physical property evaluation results of the films of Examples 1 to 7 and Comparative Examples 1 and 2 are shown in Table 1 below.

From the results of the above physical property evaluation, the copolymerized polyamideimide film of the example of the present invention has an increase in yellowing in optical properties and a decrease in average transmittance little by little when compared with Comparative Example 1 of polyimide film. I understand. This is because the polyamide component is relatively easier to form intermolecular and intramolecular charge transfer complexes than the polyimide component. Contrary to this, it can be confirmed that the coefficient of thermal expansion of the copolymerized polyamideimide film is greatly reduced, but this is because the polyamide component composed of TFDB and TPC is excellent in rigidity, and therefore has a relatively high thermal expansion. It is expected to be manifested by preventing elongation of a polyimide component having a coefficient.

The copolymerized polyamideimide film of Example 7 has almost no change in the coefficient of thermal expansion when the content of the polyamide component is increased when compared with that of Example 6,
As the polyamide component increases, the viscosity of the copolymerized polyamideimide film increases rapidly, and the degree of polymerization becomes difficult to control, so that it is expected that the polymerization reaction does not occur sufficiently and thus occurs.

The polyamide film of Comparative Example 2 shows the best thermal expansion coefficient, but has poor optical properties and is difficult to handle in the film-forming process due to its high viscosity during polymerization, and has a viscosity for easy film formation. In the case of lowering the thickness, there is a limit that the film thickness cannot be increased because the concentration is too low. Nevertheless, if the thickness is increased, the optical transmittance and the yellowing degree are rapidly deteriorated. There was a problem that it became difficult.

Although the preferred embodiments of the present invention have been disclosed for the purpose of illustration, those skilled in the art will recognize that various modifications and additions can be made without departing from the spirit and scope of the present invention as disclosed in the appended claims. It will be understood that and substitutions may be added.

Claims (6)

Unit structure derived from TFDB (2,2'-bis trifluoromethyl-4,4'-biphenyl diamine), unit structure derived from 6FDA (4,4 '-(hexa-fluoroisopropylidene) diphthalic anhydride), and TPC (Terephthaloyl chloride) ; see containing the 1,4-benzenedicarbonyl chloride) unit structure derived from the copolymerized resin,
Does not contain unit structure derived from BPDA (3,3 ', 4,4'-Biphenyltetracarboxylic Dianhydride)
In the copolymerized resin, the unit structure derived from TFDB, the unit structure derived from 6FDA, and the unit structure derived from TPC are in a molar ratio of 1: 0.2 to 0.8: 0.8 to 0.2. A copolymerized polyamide-imide film characterized by being copolymerized . In the copolymerized resin, the unit structure derived from TFDB, the unit structure derived from 6FDA, and the unit structure derived from TPC are in a molar ratio of 1: 0.3 to 0.7: 0.7 to 0.3. The copolymerized polyamideimide film according to claim 1, which has been copolymerized. The copolymerized polyamideimide film according to claim 1 or 2 , wherein the copolymerized resin has a weight average molecular weight of 10,000 to 400,000. After reacting and polymerizing TFDB (2,2'-bis trifluoromethyl-4,4'-biphenyl diamine) and 6FDA (4,4 '-(hexa-fluoroisopropylidene) diphthalic anhydride) having a smaller number of moles than this A copolymerized polyamideimide obtained by further polymerizing the obtained polymer with TPC (Terephthaloyl chloride; 1,4-benzenedicarbonyl chloride) and imidizing it. The unit structure derived from TFDB, the unit structure derived from 6FDA, and the unit structure derived from TPC are in a molar ratio of 1: 0.2 to 0.8: 0.8 to 0.2. Copolyamideimide. The copolymerized polyamideimide according to claim 4 or 5, having a weight average molecular weight of 10,000 to 400,000.

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