Polyamideimide copolymer and polyamideimide film comprising the same

Abstract

The present invention relates to a polyamideimide copolymer and a colorless and transparent polyamideimide copolymer film. The polyamideimide copolymer according to the present invention enables to provide a polyamideimide film having improved UV shielding function while exhibiting excellent scratch resistance and mechanical properties.

Claims

1. A polyamideimide film comprising a polyamideimide copolymer which is an imidization product of polyamic acid comprising copolymerized aromatic diamine monomer, aromatic dianhydride monomer, and aromatic dicarbonyl monomer, wherein the aromatic dicarbonyl monomer is contained in an amount of 51 mol % or more based on the total moles of the aromatic dianhydride monomer and the aromatic dicarbonyl monomer, wherein the aromatic dicarbonyl monomer comprises 10 mol % to 50 mol % of 4,4′-biphenyldicarbonyl chloride, 10 mol % to 30 mol % of isophthaloyl chloride, and 40 mol % to 60 mol % of terephthaloyl chloride based on the total moles of the aromatic dicarbonyl monomer, and wherein the UV-cut slope (dT/dλ) measured for a film specimen having a thickness of 25 to 55 μm according to ASTM E424 is at least 2.88 in the range of 10% to 80% transmittance.

2. The polyamideimide film of claim 1, wherein the aromatic diamine monomer is 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine.

3. The polyamideimide film of claim 1, wherein the aromatic dianhydride monomer is 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride.

4. The polyamideimide film of claim 1, wherein the pencil hardness measured for a film specimen having a thickness of 25 to 55 μm according to ASTM D3363 is 2H or higher.

5. The polyamideimide film of claim 1, wherein the tensile strength measured for a film specimen having a thickness of 25 to 55 μm according to ASTM D638 is 180 MPa or more.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 shows the measurement result of transmittance of the polyamideimide films prepared in Example 2 and Comparative Example 1 relative to the wavelengths.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(2) Below, preferred examples are provided to aid in the understanding of the present invention. However, the following examples are provided only for illustration of the invention, and should not be construed as limiting the scope of the present invention.

Preparation of Polyamideimide Copolymer

Preparation Example 1

(3) 42.5 g of N,N-dimethylacetamide (DMAc) was filled into a 100 mL 4-neck round flask (reactor) equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser while passing nitrogen through the reactor. Then, the temperature of the reactor was adjusted to 25° C., and 4.3025 g (0.01343 mol) of 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) was added and dissolved, and the resulting solution was maintained at 25° C.

(4) Hereto, 1.1859 g (0.00403 mol) of 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA) was added together, and then dissolved and reacted with stirring for a predetermined period of time. At this time, the temperature of the solution was maintained at 25° C.

(5) Subsequently, the solution was cooled down to −10° C., and then 0.375 g (0.00134 mol) of biphenyldicarbonyl chloride (BPC), 1.0911 g (0.00537 mol) of terephthaloyl chloride (TPC), and 0.5455 g (0.00269 mol) of isophthaloyl chloride (IPC) were each added and stirred. A polyamic acid solution having a solid content of 15% by weight was obtained.

(6) DMAc was added to the polyamic acid solution to dilute the solution to a solid content of 5% or less, and the resultant was precipitated with 10 L of methanol. The precipitated solids were filtered and dried at 100° C. under vacuum for 6 hours to obtain a solid-state polyamideimide copolymer (weight average molecular weight of about 121,441 g/mol).

Preparation Example 2

(7) 42.5 g of N,N-dimethylacetamide (DMAc) was filled into a 100 mL 4-neck round flask (reactor) equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser while passing nitrogen through the reactor. Then, the temperature of the reactor was adjusted to 25° C., and 4.2446 g (0.01325 mol) of 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) was added and dissolved, and the resulting solution was maintained at 25° C.

(8) Hereto, 1.17 g (0.003983 mol) of 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA) was added together, and then dissolved and reacted with stirring for a predetermined period of time. At this time, the temperature of the solution was maintained at 25° C.

(9) Subsequently, the solution was cooled down to −10° C., and then 0.740 g (0.00265 mol) of biphenyldicarbonyl chloride (BPC), 0.8073 g (0.00397 mol) of terephthaloyl chloride (TPC), and 0.5382 g (0.00265 mol) of isophthaloyl chloride (IPC) were each added and stirred. A polyamic acid solution having a solid content of 15% by weight was obtained.

(10) DMAc was added to the polyamic acid solution to dilute the solution to a solid content of 5% or less, and the resultant was precipitated with 10 L of methanol. The precipitated solids were filtered and dried at 100° C. under vacuum for 6 hours to obtain a solid-state polyamideimide copolymer (weight average molecular weight of about 97,447 g/mol).

Preparation Example 3

(11) 42.5 g of N,N-dimethylacetamide (DMAc) was filled into a 100 mL 4-neck round flask (reactor) equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser while passing nitrogen through the reactor. Then, the temperature of the reactor was adjusted to 25° C., and 4.1883 g (0.01308 mol) of 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) was added and dissolved, and the resulting solution was maintained at 25° C.

(12) Hereto, 1.1544 g (0.003924 mol) of 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA) was added together, and then dissolved and reacted with stirring for a predetermined period of time. At this time, the temperature of the solution was maintained at 25° C.

(13) Subsequently, the solution was cooled down to −10° C., and then 1.0952 g (0.00392 mol) of biphenyldicarbonyl chloride (BPC), 0.7966 g (0.00392 mol) of terephthaloyl chloride (TPC), and 0.2655 g (0.001308 mol) of isophthaloyl chloride (IPC) were each added and stirred. A polyamic acid solution having a solid content of 15% by weight was obtained.

(14) DMAc was added to the polyamic acid solution to dilute the solution to a solid content of 5% or less, and the resultant was precipitated with 10 L of methanol. The precipitated solids were filtered and dried at 100° C. under vacuum for 6 hours to obtain a solid-state polyamideimide copolymer (weight average molecular weight of about 88,736 g/mol).

Comparative Preparation Example 1

(15) 42.5 g of N,N-dimethylacetamide (DMAc) was filled into a 100 mL 4-neck round flask (reactor) equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser while passing nitrogen through the reactor. Then, the temperature of the reactor was adjusted to 25° C., and 4.3619 g (0.0136 mol) of 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) was added and dissolved, and the resulting solution was maintained at 25° C.

(16) Hereto, 1.2023 g (0.00408 mol) of 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA) was added together, and then dissolved and reacted with stirring for a predetermined period of time. At this time, the temperature of the solution was maintained at 25° C. Subsequently, the solution was cooled to −10° C., and 1.3827 g (0.00681 mol) of terephthaloyl chloride (TPC) and 0.5531 g (0.00272 mol) of isophthaloyl chloride (IPC) were each added and stirred. A polyamic acid solution having a solid content of 15% by weight was obtained.

(17) DMAc was added to the polyamic acid solution to dilute the solution to a solid content of 5% or less, and the resultant was precipitated with 10 L of methanol. The precipitated solids were filtered and dried at 100° C. under vacuum for 6 hours to obtain a solid-state polyamideimide copolymer (weight average molecular weight of about 88,147 g/mol).

Comparative Preparation Example 2

(18) 42.5 g of N,N-dimethylacetamide (DMAc) was filled into a 100 mL 4-neck round flask (reactor) equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser while passing nitrogen through the reactor. Then, the temperature of the reactor was adjusted to 25° C., and 4.1334 g (0.01290 mol) of 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) was added and dissolved, and the resulting solution was maintained at 25° C.

(19) Hereto, 1.1393 g (0.003872 mol) of 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA) was added together, and then dissolved and reacted with stirring for a predetermined period of time. At this time, the temperature of the solution was maintained at 25° C.

(20) Subsequently, the solution was cooled to −10° C., and then 1.4411 g (0.0051631 mol) of biphenyldicarbonyl chloride (BPC), 0.2621 g (0.001290 mol) of terephthaloyl chloride (TPC), and 0.5241 g (0.002581 mol) of isophthaloyl chloride (IPC) were each added and stirred. A polyamic acid solution having a solid content of 15% by weight was obtained.

(21) DMAc was added to the polyamic acid solution to dilute the solution to a solid content of 5% or less, and the resultant was precipitated with 10 L of methanol. The precipitated solids were filtered and dried at 100° C. under vacuum for 6 hours to obtain a solid-state polyamideimide copolymer (weight average molecular weight of about 101,851 g/mol).

Comparative Preparation Example 3

(22) 42.5 g of N,N-dimethylacetamide (DMAc) was filled into a 100 mL 4-neck round flask (reactor) equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser while passing nitrogen through the reactor. Then, the temperature of the reactor was adjusted to 25° C., and 4.3320 g (0.01352 mol) of 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) was added and dissolved, and the resulting solution was maintained at 25° C.

(23) Hereto, 1.1940 g (0.00406 mol) of 3,3′,4,4′-biphenyltetracarboxylic acid dianhydride (BPDA) was added together, and then dissolved and reacted with stirring for a predetermined period of time. At this time, the temperature of the solution was maintained at 25° C.

(24) Subsequently, the solution was cooled down to −10° C., and then 0.1888 g (0.00068 mol) of biphenyldicarbonyl chloride (BPC), 1.0986 g (0.00541 mol) of terephthaloyl chloride (TPC), and 0.686 g (0.00338 mol) of isophthaloyl chloride (IPC) were each added and stirred. A polyamic acid solution having a solid content of 15% by weight was obtained.

(25) DMAc was added to the polyamic acid solution to dilute the solution to a solid content of 5% or less, and the resultant was precipitated with 10 L of methanol. The precipitated solids were filtered and dried at 100° C. under vacuum for 6 hours to obtain a solid-state polyamideimide copolymer (weight average molecular weight of about 79,171 g/mol).

(26) The following Table 1 summarizes the content of monomers used in the

(27) Preparation Examples 1 to 3 and Comparative Preparation Examples 1 to 3.

(28) TABLE-US-00001 TABLE 1 (Based on total moles of (Based on total moles of Molar ratio of BPDA + BPC + IPC + TPC) BPC + IPC + TPC) (TFDB):(BPDA + BPDA BPC IPC TPC BPC IPC TPC BPC + IPC + TPC) (mole %) (mole %) (mole %) (mole %) (mole %) (mole %) (mole %) Preparation 1:1 30.0 10.0 20.0 40.0 14.3 28.6 57.1 Example 1 Preparation 1:1 30.0 20.0 20.0 30.0 28.6 28.6 42.8 Example 2 Preparation 1:1 30.0 30.0 10.0 30.0 42.85 14.3 42.85 Example 3 Comparative 1:1 30.0 — 20.0 50.0 — 28.5 71.5 Preparation Example 1 Comparative 1:1 30.0 40.0 20.0 10.0 57.1 28.6 14.3 Preparation Example 2 Comparative 1:1 30.0  5.0 25.0 40.0 7.2 35.7 57.1 Preparation Example 3

Preparation of Polyamideimide Film

Example 1

(29) The polyamideimide copolymer obtained in Preparation Example 1 was dissolved in dimethylacetamide to prepare a polymer solution having a concentration of about 25% (w/v). The polymer solution was poured onto a glass substrate, and the thickness of the polymer solution was uniformly adjusted using a film applicator. Then, the solution was dried at 70° C. for 5 minutes and at 100° C. for 10 minutes in a vacuum oven, and the formed film was peeled off.

(30) The peeled film was fixed to the frame of the vacuum oven and then cured at 250° C. for 30 minutes while flowing nitrogen to obtain a polyamideimide film having a thickness of 53.2 μm.

Example 2, Example 3, and Comparative Examples 1 to 3

(31) Polyamideimide films having a thickness shown in Table 1 below were obtained in the same manner as in Example 1, except that the polyamideimide copolymers obtained in Preparation Example 2, Preparation Example 3, and Comparative Preparation Examples 1 to 3 were used respectively.

Experimental Example

(32) The physical properties of the polyamideimide films prepared in Examples 1 to 3 and Comparative Examples 1 to 3 were evaluated by the following methods, and the results are shown in Table 2 below. The transmittance graphs of Example 2 and Comparative Example 1 is shown in FIG. 1.

(1) Pencil Hardness

(33) The pencil hardness of the film was measured according to the measurement method of ASTM D3363 using a pencil hardness tester. Specifically, a pencil of various hardness was fixed on the tester and scratched on the film, and the degree of occurrence of a scratch on the film was observed with a naked eye or a microscope. When there was no scratch of 70% or more of the total number of scratches, a value corresponding to the hardness of the pencil was evaluated as the pencil hardness of the film.

(2) Elastic Modulus, Tensile Strength, and Tensile Elongation

(34) The elastic modulus, tensile strength, and tensile elongation were measured according to the measurement method of IPC-TM-650 using a tensile strength measuring device (manufacturer: Instron, model: 3345 UTM).

(3) Yellow Index (Y.I.)

(35) The yellow index of the film was measured according to the measurement method of ASTM E313 using a COH-400 Spectrophotometer (NIPPON DENSHOKU INDUSTRIES).

(4) Transmittance (T)

(36) The total light transmittance of the film was measured using a UV-VIS-NIR Spectrophotometer (SolidSpec-3700, SHIMADZU), and the transmittance for visible light at a wavelength of 550 nm is shown in Table 2 below.

(5) UV-Cut Off Wavelength(λ) and UV-Cut Slope (dT/dλ)

(37) The UV-cut off wavelength (λ) and UV-cut slope (dT/dλ) of the film were measured according to the measurement method of ASTM E424 using a UV-Vis spectrophotometer (manufacturer: Shimadzu, model: UV2600). The UV-cut slope (dT/dλ) was measured in the range of 10% to 80% transmittance, and the UV-cut off was expressed as the wavelength when the transmittance was less than 1%.

(38) TABLE-US-00002 TABLE 2 Aromatic dicarbonyl Tensile monomer Thick- Pencil Elastic Tensile elonga- BPC IPC TPC ness hard- modulus strength tion T λ dT/ (mole %) (mole %) (mole %) (μm) ness (GPa) (MPa) (%) Y.I. (%) (nm) dλ Example 1 14.3 28.6 57.1 52.1 2H 4.97 228 26 3.12 89.5 383 2.88 Example 2 28.6 28.6 42.8 50.4 2H 5.41 241 22 3.17 89.1 384 2.91 Example 3 42.85 14.3 42.85 51.3 2H 5.9 268 30 3.05 89.1 389 2.94 Comparative — 28.5 71.5 53.2 H 4.44 175 17 3.18 88.9 378 2.59 Example 1 Comparative 57.1 28.6 14.3 50.8 Measure- 6.42 300 25 Measure- Measure- Measure- Measure- Example 2 ment not ment not ment not ment not ment not possible possible possible possible possible Comparative 7.2 35.7 57.1 49.2 H 4.52 166 25 3.09 88.9 383 2.78 Example 3

(39) Referring to Table 2 and FIG. 1, it was confirmed that, as for the film according to Comparative Example 2 having a high content of BPC, it was impossible to measure the optical-related physical properties due to haze, whereas the films according to Examples, in which an appropriate amount of BPC was used, not only had improved scratch resistance due to high pencil hardness compared to the films according to Comparative Examples, but also showed excellent mechanical properties and increased UV-cut slope.