KR102193140B1 - Preparation method for transparent plastic film - Google Patents

Abstract

The present invention provides a partially imidized poly(amide-imide) copolymer by reacting an alicyclic or aromatic tetracarboxylic anhydride and an aromatic dicarboxylic acid or a derivative thereof with an aromatic diamine compound at -30°C to 120°C. Forming; And coating the partially imidized poly(amide-imide) copolymer on a substrate and heating to a temperature of 80° C. or higher. It relates to a method for producing a transparent plastic film.

Description

Manufacturing method of transparent plastic film {PREPARATION METHOD FOR TRANSPARENT PLASTIC FILM}

The present invention relates to a method for producing a transparent plastic film having high hardness.

Aromatic polyimide resins are mostly polymers having an amorphous structure and exhibit excellent heat resistance, chemical resistance, electrical properties, and dimensional stability due to a rigid chain structure. These polyimide resins are widely used as electrical/electronic materials. However, polyimide resins are limited in use because they have a dark brown color due to the formation of a charge transfer complex (CTC) of π electrons present in the imide chain.

In order to overcome the above limitation and obtain a colorless transparent polyimide resin, a method of restricting the movement of π electrons by introducing a strong electron attracting group such as a trifluoroalkyl group; A method of reducing the formation of the CTC by introducing a sulfone (-SO2-) group, an ether (-O-) group, etc. to the main chain to form a curved structure; Alternatively, a method of inhibiting the formation of a resonance structure of π electrons by introducing an alicyclic compound has been proposed.

However, the polyimide resin according to the above proposals is difficult to exhibit sufficient heat resistance due to a bent structure or an alicyclic compound, and a film manufactured using the polyimide resin still has a limitation in showing poor mechanical properties.

On the other hand, in recent years, in order to improve the scratch resistance of the polyimide, a poly(amide-imide) copolymer in which a polyamide unit structure is introduced has been developed.

However, the poly(amide-imide) copolymer exhibits a tendency to haze easily when a film is formed by coating it due to its high crystallinity. This haze property of the poly(amide-imide) film is expressed more severely as the thickness of the film is thicker and also affects the yellow index (Y.I.).

However, a copolymerized polyamide-imide film which satisfies both the thermal and mechanical properties and optical properties required by the market at the same time has not been provided. Therefore, there is a need to develop a copolymerized polyamide-imide capable of producing a transparent film having excellent thermal, mechanical, and optical properties.

The present invention is to provide a transparent plastic film having high transparency along with mechanical properties such as high scratch resistance and hardness.

In the present specification, a partially imidized poly(amide-imide) copolymer by reacting an alicyclic or aromatic tetracarboxylic anhydride and an aromatic dicarboxylic acid or a derivative thereof with an aromatic diamine compound at -30°C to 120°C Forming a; And coating the partially imidized poly(amide-imide) copolymer on a substrate and heating to a temperature of 80° C. or higher. A method for producing a transparent plastic film is provided.

Hereinafter, a method of manufacturing a transparent plastic film according to a specific embodiment of the present invention will be described in more detail.

As described above, according to one embodiment of the invention, partially imidized by reacting an alicyclic or aromatic tetracarboxylic anhydride and an aromatic dicarboxylic acid or derivative thereof with an aromatic diamine compound at -30°C to 120°C. Forming a poly(amide-imide) copolymer; And coating the partially imidized poly(amide-imide) copolymer on a substrate and heating it to a temperature of 80° C. or higher. A method for producing a transparent plastic film may be provided.

According to the development trend of flexible or foldable devices, there is a need to implement a display that is light, unbreakable, and foldable or rollable. In addition, there is a demand for a colorless, transparent film with high hardness and good repeatability for implementing such a display. As a material for simultaneously satisfying high hardness and repeatability, poly(amide-imide) copolymers obtained by copolymerizing an aromatic amide and an aromatic imide are emerging. However, the poly(amide-imide) copolymer obtained by copolymerizing an aromatic amide and an aromatic imide has a limitation that is not suitable for use in the display field due to its own color.

Accordingly, the present inventors continued research on the production of a high-hardness transparent plastic film using a poly(amide-imide) copolymer, and alicyclic or aromatic tetracarboxylic anhydride and aromatic dicarboxylic acid or derivatives thereof Reaction with a diamine compound at -30°C to 120°C to form a partially imidized poly(amide-imide) copolymer, and not separately imidizing the partially imidized poly(amide-imide) copolymer It was confirmed through an experiment that a transparent plastic film having high transparency along with mechanical properties such as high scratch resistance and hardness can be produced when coated on a substrate in a state of being not heated and heated.

Previously, a copolymer obtained by reacting an aromatic amide with monomers forming an aromatic imide was chemically imidized to obtain a poly(amide-imide) copolymer imidized at least 90 mol% or 100 mol%. The poly(amide-imide) copolymer obtained according to the method has low light transmittance or high yellowness and is not suitable for use in the display field. In particular, haze occurs when manufactured as a film having a thickness of 10 μm or more or 30 μm or more. There were limitations such as that.

More specifically, by reacting an alicyclic or aromatic tetracarboxylic anhydride and an aromatic dicarboxylic acid or derivative thereof with an aromatic diamine compound at -30°C to 120°C, 1 mol% to 20 mol%, or 2 mol% to In the range of 10 mol% A partially imidized poly(amide-imide) copolymer can be obtained, and the partially imidized poly(amide-imide) copolymer is coated in a film or sheet form and heat treated to achieve high light transmittance and low yellowness. Together, a transparent plastic film having excellent mechanical properties can be prepared.

The partial imidation rate of the poly(amide-imide) copolymer can be confirmed through a commonly known method, for example, an IR spectrum. For example, after dividing the area of imide intrinsic peaks on the IR spectrum of the poly(amide-imide) copolymer by the area of characteristic peaks of the standard aromatic ring (reference value, all the same values), the values are each at high temperature. The imidation rate can be calculated by relatively comparing the calculated value for the completely imidized compound as 100%.

Accordingly, the method of manufacturing the transparent plastic film of the embodiment is characterized in that the partially imidized poly(amide-imide) copolymer does not undergo thermal imidization or chemical imidization before coating on the substrate. To do.

As commonly known, the thermal imidation may be performed using a method of heat treatment at a temperature of 150°C or higher, and the chemical imidization may be performed using a method of chemically performing an imidation reaction using a dehydration catalyst. have.

Accordingly, in the method for producing a transparent plastic film of the embodiment, before forming the partially imidized poly(amide-imide) copolymer and coating it on the substrate, the partially imidized poly(amide) It is characterized in that the -imide) copolymer is not reacted with the dehydration catalyst.

As the dehydration catalyst, aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides may be used, and aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethyl aniline, pyridine, isoquinoline, β- Heterocyclic tertiary amines, such as ficoline, γ-picoline, and 3,5-lutidine, can be used.

On the other hand, in the method for manufacturing a transparent plastic film of the embodiment, the partially imidized poly(amide-imide) copolymer is coated on a substrate and heated to a temperature of 80° C. or higher; The deformed poly(amide-imide) copolymer can be prepared in the shape of a film.

In the manufacturing method of the transparent plastic film of the above embodiment, a problem such as haze occurs even when manufacturing a film having a thickness of 30 μm or more, or 50 μm or more, or 30 μm to 200 μm, or 50 μm to 150 μm. Can be prevented.

Accordingly, in the step of coating the partially imidized poly(amide-imide) copolymer on a substrate and heating it to a temperature of 80° C. or higher, the thickness of the finally produced transparent plastic film is 30 μm or more, 30 μm or more. It may include the step of coating the partially imidized poly (amide-imide) copolymer on a substrate so as to be 1,000 μm.

The partially imidized poly(amide-imide) copolymer may be coated on the substrate in a state dissolved in an organic solvent. Accordingly, the step of coating the partially imidized poly(amide-imide) copolymer on a substrate and heating it to a temperature of 80° C. or higher, the partially imidized poly(amide-imide) copolymer It may include coating a polymer solution dissolved in an organic solvent on the substrate to a thickness of 30 μm to 3,000 μm. At this time, examples of the organic solvent that can be used are not largely limited, and for example, N-methylpyrrolidinone (NMP), N,N-dimethylacetamide (N,N-dimethylacetamide; DMAc), tetrahydro Furan (tetrahydrofuran; THF), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), cyclohexane, acetonitrile, ethyl lactate (Ethyl) lactate) and mixtures thereof may be used.

The partially imidized poly(amide-imide) copolymer coated on the substrate may be heated to a temperature of 80°C to 300°C, or 100°C to 250°C.

In addition, the step of coating the partially imidized poly(amide-imide) copolymer to a thickness of 30 μm or more on a substrate and heating to a temperature of 80° C. or more may include partially coated on the substrate to a thickness of 30 μm or more. It may include the step of heating the imidized poly (amide-imide) copolymer at a temperature of 200 ℃ or more for 1 minute or more.

As described above, when the partially imidized poly(amide-imide) copolymer is coated on a substrate and heated to 80°C or higher, 80°C to 300°C, or 100°C to 250°C or higher, the Partially imidized poly (amide-imide) polymer structure or arrangement inside the copolymer may be oriented or vertically oriented in the direction of the coating surface, and the partially imidized poly (amide-imide) copolymer The imidation rate of may gradually increase.

Materials that can be used as an arbitrary support for coating a solution containing the poly(amide-imide) copolymer are not largely limited, for example, various polymer substrates or plastic substrates, glass substrates, metal substrates such as copper, etc. You can use

In addition, in the step of applying the solution containing the poly(amide-imide) copolymer on the support, a commonly used application method and apparatus may be used without any other limitation. For example, a spray method, Roll coating method, rotation coating method, slit coating method, extrusion coating method, curtain coating method, die coating method, wire bar coating method, knife coating method, or the like can be used.

In addition, in the manufacturing step of the plastic film, a step of drying a solution containing the applied poly(amide-imide) copolymer may be included. The polymer resin solution applied on the support may be dried at a temperature lower than the boiling point of the solvent used, for example, at 60 to 200° C. for 30 seconds to 30 minutes. In the drying step, an arch-type oven or a floating-type oven may be used.

On the other hand, the alicyclic or aromatic tetracarboxylic anhydride and aromatic dicarboxylic acid or derivatives thereof used to form the partially imidized poly(amide-imide) copolymer are largely limited to each example of the aromatic diamine compound. no.

However, considering the optical properties and mechanical properties of the final plastic film, the alicyclic or aromatic tetracarboxylic anhydride is an alicyclic tetravalent functional group having 4 to 10 carbon atoms or an aromatic tetravalent functional group having 6 to 20 carbon atoms. Tetracarboxylic acid may be included, and the aromatic dicarboxylic acid or derivative thereof may include a dicarboxylic acid or a derivative thereof containing an aromatic divalent functional group having 6 to 20 carbon atoms, and the aromatic diamine compound is It may include a diamine compound including the functional group of Formula 1.

[Formula 1]

In Formula 1, L ₁ is a single bond, -O-, -CO-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -CONH-, -COO-, -(CH ₂ ) _n1 -, -O(CH ₂ ) _n2 O-, -OCH ₂ -C(CH ₃ ) ₂ -CH ₂ O- or -OCO(CH ₂ ) _n3 OCO-, and the n1, n2 and n3 are each an integer of 1 to 10, R ₁ and R ₂ may be the same as or different from each other, and each of a perfluoro alkyl having 1 to 5 carbon atoms to be.

The poly(amide-imide) copolymer may have a weight average molecular weight of 5,000 to 500,000, or a weight average molecular weight of 30,000 to 300,000. The weight average molecular weight may be a weight average molecular weight in terms of polystyrene measured by GPC method.

There is no great limitation on the synthesis method of the poly(amide-imide) copolymer, and a conventionally known synthesis apparatus and method may be used using the above-described monomer. For example, after dissolving the above-described monomer in a commonly known organic solvent, the polymerization reaction may be performed at a temperature range of -30°C to 120°C, or -10°C to 100°C, and the polymerization reaction time is also greatly limited. It doesn't work.

Examples of organic solvents that can be used in the polymerization process are also not very limited, and for example, N-methylpyrrolidinone (NMP), N,N-dimethylacetamide (N,N-dimethylacetamide; DMAc) ), tetrahydrofuran (THF), N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), cyclohexane, acetonitrile, ethyl One or more selected from the group consisting of lactate (Ethyl lactate) and mixtures thereof may be used.

In addition, the poly(amide-imide) copolymer may be finally obtained through a conventional polymer recovery process such as precipitation, filtration, and drying after the formation step of the copolymer.

The prepared transparent plastic film may have excellent weather resistance while having high transparency and mechanical properties such as high scratch resistance. Accordingly, the plastic film formed from the poly(amide-imide) copolymer can be used as a material for various molded articles requiring high scratch resistance and excellent weather resistance along with colorless transparency. For example, the transparent plastic film may be applied to a display substrate, a protective film for a display, a touch panel, or the like.

The transparent plastic film may have a pencil hardness of 50 ± 2 µm and a pencil hardness of H grade or higher measured according to ASTM D3363. In addition, the plastic film may have a transmittance of 85% or more in a wavelength range of 400 nm to 600 nm.

Except for the use of the above-described poly(amide-imide) copolymer, the plastic film may use various commonly known methods and apparatus for manufacturing a plastic film without any other limitation. For example, the plastic film may be obtained by coating a solution containing the poly(amide-imide) copolymer on an arbitrary support to form a film, and drying by evaporating a solvent from the film. Stretching and heat treatment may be performed on the plastic film.

According to the present invention, a poly(amide-imide) copolymer having excellent weather resistance while having mechanical properties such as high scratch resistance and high transparency, and a plastic film including the same can be provided.

The invention will be described in more detail in the following examples. However, the following examples are merely illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

[ Example And Comparative example : Poly Synthesis of (amide-imide) copolymer and production of plastic film]

Example 1

(One) Poly Synthesis of (amide-imide) copolymer

While slowly blowing nitrogen into a 0.5 L reactor equipped with a stirrer, nitrogen injector, dropping funnel, and temperature controller, 138 g of dimethylacetamide (DMAC) was filled, and the temperature of the reactor was adjusted to 25 °C, and then TFDB (2,2' -bis(trifluoromethyl)-4,4-diaminobiphenyl) 11.973 (0.037 mol) was added and dissolved, and maintained at 25.

3.3 g (0.011 mol) of BPDA (3,3',4,4'-Biphenyltetracarboxylic dianhydride) was added to the reactor, followed by stirring for 1 hour to dissolve and react, and the temperature of the reaction solution was maintained at 25°C.

And after cooling the temperature of the reaction solution to -10 ℃, TPC (terephthaloyl chloride) 5.313g (0.026mol) was added and stirred to obtain a polymer solution having a solid content of 13% by weight. DMAC was added to the polymer solution, diluted to 5% or less of solid content, precipitated with 10 L of methanol, filtered, and dried for 6 hours or more in a vacuum of 100 to 10 torr or less to form a copolymerized polyamide in solid form- I got the imide. At this time, the imidation ratio of the copolymerized polyamide-imide is about 5 mol%.

The method of measuring and calculating the imidation rate of the copolymerized polyamide-imide is as follows (the imidation rate was calculated by the same method in the following Examples and Comparative Examples): Using a Fourier transform infrared spectrometer (FT-IR) The IR spectrum of the poly(amide-imide) copolymer was measured, and the areas of the carbonyl group (-C=O) characteristic peak (1720 cm ^-1 ) and the CN stretch characteristic peak (1370 cm ^{- 1} ) of the imide ring were measured. It was calculated by dividing by the area of the absorption peak near 1500 cm ^-1 representing the aromatic moiety, which is the internal standard peak (calculated value 1). Then, the calculated value for the completely cured poly(amide-imide) copolymer was set to 100% (calculated value 2), and the imidation rate was calculated through relative comparison of the calculated values 1 and 2.

(2) Preparation of transparent plastic film

The poly(amide-imide) copolymer in the solid form was dissolved in dimethylacetamide to have a solid content of 15% by weight, and then coated on a glass plate to a final thickness of 50 μm.

After the glass plate is coated, drying at 80° C. for 10 minutes is repeated twice, and then the film coated with the poly(amide-imide) copolymer solution is fixed to the glass plate and placed in a curing oven where nitrogen is purged. After heating slowly (holding 250/30 minutes) for 2 hours from to 250, it was gradually cooled and separated from the glass plate to obtain a transparent polyamideimide film (thickness of 50 μm).

Example 2

A poly(amide-imide) copolymer and a plastic film were prepared in the same manner as in Example 1, except that the amounts of BPDA and TPC were different as shown in Table 1 below.

Comparative example One

While slowly blowing nitrogen into a 0.5 L reactor equipped with a stirrer, nitrogen injector, dropping funnel, and temperature controller, 138 g of dimethylacetamide (DMAC) was filled, and the temperature of the reactor was adjusted to 25 °C, and then TFDB (2,2' -bis(trifluoromethyl)-4,4-diaminobiphenyl) 11.973 (0.037 mol) was added and dissolved, and maintained at 25.

3.3 g (0.011 mol) of BPDA (3,3',4,4'-Biphenyltetracarboxylic dianhydride) was added to the reactor, followed by stirring for 1 hour to dissolve and react, and the temperature of the reaction solution was maintained at 25°C.

And after cooling the temperature of the reaction solution to -10 ℃, TPC (terephthaloyl chloride) 5.313g (0.026mol) was added and stirred to obtain a polymer solution having a solid content of 13% by weight.

1.77g of pyridine and 2.29g of acetic anhydride were added to a polymer solution having a concentration of the solid content of 13% by weight, stirred for 30 minutes, and then stirred at 70 for 1 hour to cool to room temperature.

Thereafter, DMAC was added to the polymer solution, diluted to 5% or less of solid content, precipitated with 10 L of methanol, filtered, and dried in vacuum at 100 for 6 hours or longer to form a copolymer polyamide-imide in solid form. Got it. At this time, the imidation rate of the copolymerized polyamide-imide is about 95 mol%.

(2) Preparation of transparent plastic film

The poly(amide-imide) copolymer in the solid form was dissolved in dimethylacetamide to have a solid content of 15% by weight, and then coated on a glass plate to a final thickness of 335 μm.

After the glass plate is coated, drying at 80° C. for 10 minutes is repeated twice, and then the film coated with the poly(amide-imide) copolymer solution is fixed to the glass plate and placed in a curing oven where nitrogen is purged. After heating slowly (holding 250/30 minutes) for 2 hours from to 250, it was gradually cooled and separated from the glass plate to obtain a transparent polyamideimide film (thickness of 50 μm).

Comparative Example 2

A poly(amide-imide) copolymer and a plastic film were prepared in the same manner as in Comparative Example 1, except that the amounts of BPDA and TPC were different as shown in Table 1 below.

A poly(amide-imide) copolymer and a plastic film were prepared in the same manner as in Example 1, except that the content of the monomers used was different as shown in Table 1 below.

Composition ratio (molar basis of TFDB) Dehydration catalyst
Whether or not to use TFDB BPDA TPC Example 1 1.0 0.3 0.7 X Example 2 1.0 0.2 0.8 X Comparative Example 1 1.0 0.3 0.7 O Comparative Example 2 1.0 0.2 0.8 O

[ Experimental example : Measurement of plastic film properties]

(1) Measurement of transmittance (T)

The total light transmittance of the plastic films obtained in the Examples and Comparative Examples was measured using a UV-VIS-NIR Spectrophotometer (SolidSpec-3700, SHIMADZU), and the transmittance values for visible light at a wavelength of 550 nm are shown in Table 2 below. .

(2) Yellow Index; Y.I .)

Using a UV-2600 UV-Vis Spectrometer (SHIMADZU), the yellow index (Y.I.) of the plastic films obtained in Examples and Comparative Examples was measured according to the measurement method of ASTM D1925.

(3) pencil hardness

Pencil Hardness Tester was used to measure the pencil hardness of the plastic films obtained in Examples and Comparative Examples according to the measurement method of ASTM D3363. Specifically, after fixing pencils of various hardnesses to the tester and scratching the film, the degree of scratching on the film was observed with the naked eye or a microscope, and when no more than 70% of the total number of scratches was scratched, the hardness of the pencil The corresponding value was evaluated by the pencil hardness of the film.

(4) Haze Measure

For the plastic films obtained in the above Examples and Comparative Examples, the haze of the film was specified using a spectrophotometer (device name: COH-400). As a result of measurement and evaluation, when the haze of the film is 1 or more, it is indicated as'', and when it is 1 or less, it is indicated as'X'.

(5) Flexibility Measure

With respect to the plastic films obtained in the above Examples and Comparative Examples, the MIT type folding endurance tester was used to evaluate the film's fracture strength. Specifically, a specimen of the film (1cm*7cm) was loaded into a strength tester and bent at an angle of 135° at a speed of 175 rpm from the left and right sides of the specimen, a radius of curvature of 0.8 mm, and a load of 250 g until fracture. The reciprocating bending cycle was measured.

HAZE
The presence or absence Yellow Index (Y.I.) Transmittance
(550 nm) Pencil hardness Flexibility
(MIT, Time) Example 1 X 2.63 89.3 4H 18500 Example 2 X 2.91 89 3H 16500 Comparative Example 1 16.5 45 H 6600 Comparative Example 2 15.8 37 F 4700

As can be seen in Table 2, the films prepared using the poly(amide-imide) copolymers obtained in Examples 1 and 2 secured a high light transmittance of 88% or more, and a high surface hardness of 3H or more and 15,000 cycles. It has been confirmed that not only has the high flexibility above, but also does not show haze even when manufactured to a thickness of 50 μm or more.

On the other hand, in the case of Comparative Examples 1 and 2 using the dehydration catalyst in the manufacturing process, not only haze occurs when manufactured with a thickness of 50 μm or more, but also exhibits a high yellow index, and the transmittance and surface hardness are significantly low, as well as the flexibility of the film It was confirmed that it remained at a fairly low level.

Claims (12)

Reaction of an alicyclic or aromatic tetracarboxylic anhydride and an aromatic dicarboxylic acid or derivative thereof with an aromatic diamine compound at -30°C to 120°C to form a partially imidized poly(amide-imide) copolymer ; And
Including; coating the partially imidized poly (amide-imide) copolymer on a substrate and heating to a temperature of 80 °C or higher,
The partially imidized poly(amide-imide) copolymer is imidized in 1 mol% to 20 mol%,
After the step of forming the partially imidized poly(amide-imide) copolymer until the partially imidized poly(amide-imide) copolymer is coated on a substrate, the partially imidized Characterized in that the poly(amide-imide) copolymer does not undergo thermal imidization or chemical imidization.
Method for producing a transparent plastic film.
delete delete The method of claim 1,
After the step of forming the partially imidized poly(amide-imide) copolymer until before coating the partially imidized poly(amide-imide) copolymer on a substrate,
A method for producing a transparent plastic film, characterized in that the partially imidized poly(amide-imide) copolymer is not reacted with a dehydration catalyst.
The method of claim 4,
The dehydration catalyst comprises at least one selected from the group consisting of an aliphatic acid anhydride, an aromatic acid anhydride, an aromatic tertiary amine, and a heterocyclic tertiary amine.
The method of claim 1,
Coating the partially imidized poly(amide-imide) copolymer on a substrate and heating to a temperature of 80° C. or higher,
A method for producing a transparent plastic film, comprising coating the partially imidized poly(amide-imide) copolymer on a substrate so that the thickness of the finally produced transparent plastic film is 30 μm or more.
The method of claim 1,
Coating the partially imidized poly(amide-imide) copolymer on a substrate and heating it to a temperature of 80° C. or higher,
A method for producing a transparent plastic film, comprising coating a polymer solution in which the partially imidized poly(amide-imide) copolymer is dissolved in an organic solvent to a thickness of 30 μm to 3,000 μm on the substrate.
The method of claim 1,
The partially imidized poly(amide-imide) copolymer coated on the substrate is heated to a temperature of 80° C. to 300° C., a method for producing a transparent plastic film.
The method of claim 1,
Coating the partially imidized poly(amide-imide) copolymer to a thickness of 30 μm or more on a substrate and heating to a temperature of 80° C. or more,
A method for producing a transparent plastic film, comprising heating a partially imidized poly(amide-imide) copolymer coated with a thickness of 30 μm or more on the substrate at a temperature of 200° C. or more for 1 minute or more.
The method of claim 1,
The alicyclic or aromatic tetracarboxylic anhydride includes a tetracarboxylic acid containing an alicyclic tetravalent functional group having 4 to 10 carbon atoms or an aromatic tetravalent functional group having 6 to 20 carbon atoms,
The aromatic dicarboxylic acid or derivative thereof includes a dicarboxylic acid containing an aromatic divalent functional group having 6 to 20 carbon atoms or a derivative thereof, a method for producing a transparent plastic film.
The method of claim 1,
The aromatic diamine compound comprises a diamine compound containing a functional group of the following formula (1), a method for producing a transparent plastic film:
[Formula 1]

In Formula 1,
L ₁ is a single bond, -O-, -CO-, -S-, -SO ₂ -, -C(CH ₃ ) ₂ -, -C(CF ₃ ) ₂ -, -CONH-, -COO-,- (CH ₂ ) _n1 -, -O(CH ₂ ) _n2 O-, -OCH ₂ -C(CH ₃ ) ₂ -CH ₂ O- or -OCO(CH ₂ ) _n3 OCO-, and the n1, n2 and n3 Are each an integer of 1 to 10,
R ₁ and R ₂ may be the same as or different from each other, and each of 1 to 5 carbon atoms perfluoroalkyl to be.
The method of claim 1,
The transparent plastic film has a pencil hardness of H grade or higher measured according to ASTM D3363 at a thickness of 50 ± 2 ㎛,
A method for producing a transparent plastic film having a transmittance of 85% or more in a wavelength range of 400 nm to 600 nm.