POLYAMIDE RESIN, AND POLYMER FILM, RESIN LAMINATE USING THE SAME

Abstract

The present invention relates to a polyamide resin in which an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus is 8.0 nm or less, and a UV-cut slope (dT/dλ) measured for a specimen having a thickness of 45 μm or more and 55 μm or less according to ASTM E424 is 0.25 or more in the range of 10% to 80% transmittance, and a polymer film and resin laminate using the same. In addition, the present invention relates to a polyamide resin with characteristic profile in which a small-angle X-ray scattering function obtained by irradiating the polyamide resin with X-rays having an energy of 10 KeV to 20 KeV using a small-angle X-ray scattering apparatus satisfies Equation 1 and Equation 2, and a polymer film and resin laminate using the same.

Claims

1. A polyamide resin having an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus is 8.0 nm or less, and a UV-cut slope (dT/dλ) measured for a polyamide resin specimen having a thickness of 45 μm or more and 55 μM or less according to ASTM E424 is at least 0.25 in the range of 10% to 80% transmittance.

2. The polyamide resin according to claim 1, wherein the average particle size of the individual crystals is measured through an analytical equipment by fitting a scattering pattern obtained by irradiating X-rays with energies of 10 KeV to 20 KeV in the small-angle X-ray scattering apparatus to a solid sphere model.

3. The polyamide resin according to claim 1, wherein amorphous polymer chains are present between the individual crystals having the average particle size of 8.0 nm or less.

4. The polyamide resin according to claim 3, wherein a distance between the individual crystals having the average particle size of 8.0 nm or less is 0.1 nm to 100 nm.

5. (canceled)

6. (canceled)

7. The polyamide resin according to claim 1, wherein the individual crystals having the average particle size of 8.0 nm or less comprises a first polyamide segment including a repeating unit represented by the following Chemical Formula 1, or a block comprised thereof: ##STR00022## in the Chemical Formula 1, Ar.sub.1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.

8. The polyamide resin according to claim 1, wherein a degree of crystallinity measured by the small-angle X-ray scattering apparatus is 20% or less.

9. The polyamide resin according to claim 7, wherein an amorphous polymer chains present between the individual crystals having the average particle size of 8.0 nm or less including—the first polyamide segment including the repeating unit represented by the Chemical Formula 1 or the block composed thereof comprise a second polyamide segment including a repeating unit represented by the following Chemical formula 2, or a block composed thereof: ##STR00023## in the Chemical Formula 2, Ar.sub.2 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.

10. The polyamide resin according to claim 9, wherein the first polyamide segment and the second polyamide segment form a main chain including an alternating repeating unit represented by the following Chemical Formula 3: ##STR00024## in the Chemical Formula 3, A is the first polyamide segment, and B is the second polyamide segment.

11. A polyamide resin having a small-angle X-ray scattering function I(q) that satisfies the following Equation 1 and Equation 2, wherein X-axis is a wavenumber q and Y-axis is a scattering intensity I in the small-angle X-ray scattering function I(q) and the small angle X-ray scattering function I(g) is obtained by irradiating a polyamide resin specimen having a thickness of 45 μm or more and 55 μm or less with X-rays using a small-angle X-ray scattering apparatus:
d.sup.2I(q)/dq.sup.2>0  [Equation 1] in the Equation 1, 0.003 Å.sup.−1≤q≤0.03 Å.sup.−1,
I(q)≥1 a.u.  [Equation 2] in the Equation 2, q≥0.08 Å.sup.−1.

12. The polyamide resin according to claim 11, wherein the polyamide resin further satisfies the following Equation 3 for the polyamide resin specimen having the thickness of 45 μm or more and 55 μm or less:
I(0.003 Å.sup.−1)≥1000 a.u.  [Equation 3]

13. The polyamide resin according to claim 11, wherein the polyamide resin further satisfies the following Equation 4 for the polyamide resin specimen having the thickness of 45 μm or more and 55 μm or less:
dI(q)/dq<0  [Equation 4] in the Equation 4, 0.003 Å.sup.−1≤q≤0.03 Å.sup.−1.

14. The polyamide resin according to claim 11, wherein the polyamide resin further satisfies the following Equation 5 for the polyamide resin specimen having the thickness of 45 μm or more and 55 μm or less:
100≤I(0.003 Å.sup.−1)/I(0.08 Å.sup.−1)≤1000.  [Equation 5]

15. (canceled)

16. (canceled)

17. The polyamide resin according to claim 11, wherein the polyamide resin comprises a first polyamide segment including a repeating unit represented by the following Chemical Formula 1, or a block comprised thereof: ##STR00025## in the Chemical Formula 1, Ar.sub.1 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.

18. The polyamide resin according to claim 17, wherein the polyamide resin further comprises a second polyamide segment including a repeating unit represented by the following Chemical formula 2, or a block composed thereof: ##STR00026## in the Chemical Formula 2, Ar.sub.2 is a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms.

19. The polyamide resin according to claim 7, wherein the first polyamide segment has a number average molecular weight of 100 g/mol or more and 5000 g/mol or less.

20. (canceled)

21. (canceled)

22. The polyamide resin according to claim 9, wherein based on the total repeating units contained in the polyamide resin, a content of the repeating units represented by Chemical Formula 1 is 60 mol % to 95 mol %, and a content of the repeating units represented by Chemical Formula 2 is 5 mol % to 40 mol %.

23. The polyamide resin according to claim 9, wherein the first polyamide segment and the second polyamide segment form a main chain including an alternating repeating unit represented by the following Chemical Formula 3: ##STR00027## in Chemical Formula 3, A is the first polyamide segment, and B is the second polyamide segment.

24. The polyamide resin according to claim 23, wherein the alternating repeating unit represented by Chemical Formula 3 is a repeating unit represented by the following Chemical Formula 4: ##STR00028## in the Chemical Formula 4, Ar.sub.1 and Ar.sub.2 are each independently a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, or a substituted or unsubstituted heteroarylene group having 2 to 20 carbon atoms, a1 and a2 are each independently an integer of 1 to 10, and b1 and b2 are each independently an integer of 1 to 5.

25. (canceled)

26. (canceled)

27. A polymer film comprising the polyamide resin according to claim 1.

28. A resin laminate comprising: a substrate including the polyamide resin according to claim 1; and a hard coating layer formed on at least one side of the substrate.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0270] FIG. 1 shows a schematic diagram of the crystal structure of the polyamide resin obtained in (1) of Example 1.

[0271] FIG. 2 shows a .sup.13C-NMR spectrum of the polyamide resin obtained in (1) of Example 1.

[0272] FIG. 3 shows a .sup.13C-NMR spectrum of the polyamide resin obtained in (1) of Example 2.

[0273] FIG. 4 shows a graph of a small-angle X-ray scattering function I(q) of the polyamide resin obtained in Examples and Comparative Examples.

[0274] FIG. 5 schematically shows formation of individual crystals by gathering polyamide resin chains in a bundle.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0275] Hereinafter, embodiments of the present invention will be described in more detail by way of examples. However, these examples are presented for illustrative purposes only, and are not intended to limit the scope of the present invention.

Preparation Example: Preparation of Acyl Chloride Complex

Preparation Example 1

[0276] 549.4 g (2.704 mol) of terephthaloyl chloride (TPC; melting point: 83° C.) and 120.6 g (0.594 mol) of isophthaloyl chloride (IPC: melting point: 44° C.) were added to a 1000 mL 4-neck round flask (reactor) equipped with a stirrer, a nitrogen injection device, a dropping funnel and a temperature controller, and the mixture was melt-kneaded at 100° C. for 3 hours and then cooled at 0° C. for 12 hours to prepare a complex of acylchloride (specifically, terephthaloyl chloride and isophthaloyl chloride).

[0277] Subsequently, the acyl chloride complex was grinded with a jaw crusher to prepare a powder having an average particle size of 5 mm.

Preparation Example 2

[0278] An acylchloride complex was prepared in the same manner as in Preparation Example 1, except that 569.5 g (2.803 mol) of terephthaloyl chloride (TPC: melting point: 83° C.) and 100.5 g (0.495 mol) of isophthaloyl chloride (IPC; melting point: 44° C.) were added.

Example: Preparation of Polyamide Resin and Polymer Film

Example 1

[0279] (1) Polyamide Resin

[0280] 262 g of N,N-dimethylacetamide (DMAc) was filled into a 500 mL 4-neck round flask (reactor) equipped with a stirrer, a nitrogen injection device, a dropping funnel and a temperature controller while slowly blowing nitrogen into the reactor. Then, the temperature of the reactor was adjusted to 0° C., and 14.153 g (0.0442 mol) of 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) was added and dissolved.

[0281] The mixture was stirred while adding 8.972 g (0.0442 mol) of the acyl chloride complex powder obtained in Preparation Example 1, and subjected to amide formation reaction at 0° C. for 12 hours.

[0282] After completion of the reaction, N,N-dimethylacetamide (DMAc) was added to dilute the solution to a solid content of 5% or less, and the resultant was precipitated with 1 L of methanol. The precipitated solids were filtered and then dried at 100° C. under vacuum for 6 hours or more to prepare a solid-state polyamide resin.

[0283] It was confirmed through .sup.13C-NMR shown in FIG. 2 that the polyamide resin obtained in (1) of Example 1, contained 82 mol % of the first repeating unit obtained by an amide reaction of terephthaloyl chloride (TPC) and 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) and 18 mol % of the second repeating unit obtained by an amide reaction of isophthaloyl chloride (IPC) and 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB).

[0284] (2) Polymer Film

[0285] The polyamide resin obtained in (1) of Example 1 was dissolved in N,N-dimethylacetamide to prepare about 10% (w/v) polymer solution.

[0286] The polymer solution was applied onto a polyimide base film (UPILEX-75s, UBE), and the thickness of the polymer solution was uniformly adjusted using a film applicator.

[0287] Then, after drying for 15 minutes at 80° C. Mathis oven, it was cured for 30 minutes at 250° C. while flowing nitrogen, and peeled from the substrate film to obtain a polymer film.

Example 2

[0288] (1) Polyamide Resin

[0289] A polyamide resin was prepared in the same manner as in (1) of Example 1, except that the acyl chloride complex powder obtained in Preparation Example 2 was used instead of the acyl chloride complex powder obtained in Preparation Example 1.

[0290] It was confirmed through .sup.13C-NMR shown in FIG. 3 that the polyamide resin obtained in (1) of Example 2, contained 85 mol % of the first repeating unit obtained by an amide reaction of terephthaloyl chloride (TPC) and 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB), and 15 mol % of the second repeating unit obtained by an amide reaction of isophthaloyl chloride (IPC) and 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB).

[0291] (2) Polymer Film

[0292] A polymer film was prepared in the same manner as in (2) of Example 1, except that the polyamide resin obtained in (1) of Example 2 was used instead of the polyamide resin obtained in (1) of Example 1.

Comparative Example: Preparation of Polyamide Resin and Polymer Film

Comparative Example 1

[0293] (1) Polyamide Resin

[0294] A polyamide resin was prepared in the same manner as in (1) of Example 1, except that instead of the acyl chloride complex powder obtained in Preparation Example 1, 7.358 g (0.0362 mol) of terephthaloyl chloride (TPC) and 1.615 g (0.0080 mol) of isophthaloyl chloride (IPC) were added simultaneously to perform an amide formation reaction.

[0295] (2) Polymer Film

[0296] A polymer film was prepared in the same manner as in (2) of Example 1, except that the polyamide resin obtained in (1) of Comparative Example 1 was used instead of the polyamide resin obtained in (1) of Example 1.

Comparative Example 2

[0297] (1) Polyamide Resin

[0298] A polyamide resin was prepared in the same manner as in (1) of Example 1, except that instead of the acyl chloride complex powder obtained in Preparation Example 1, 7.358 g (0.0362 mol) of terephthaloyl chloride (TPC) was first added, and then 1.615 g (0.0080 mol) of isophthaloyl chloride (IPC) was added sequentially at about 5 minute intervals to perform an amide formation reaction.

[0299] (2) Polymer Film

[0300] A polymer film was prepared in the same manner as in (2) of Example 1, except that the polyamide resin obtained in (1) of Comparative Example 2 was used instead of the polyamide resin obtained in (1) of Example 1.

Comparative Example 3

[0301] (1) Polyamide Resin

[0302] A polyamide resin was prepared in the same manner as in (1) of Example 1, except that instead of the acyl chloride complex powder obtained in Preparation Example 1, 1.615 g (0.0080 mol) of isophthaloyl chloride (IPC) was first added, and then 7.358 g (0.0362 mole) of terephthaloyl chloride (TPC) was added sequentially at about 5 minute intervals to perform an amide formation reaction.

[0303] (2) Polymer Film

[0304] A polymer film was prepared in the same manner as in (2) of Example 1, except that the polyamide resin obtained in (1) of Comparative Example 3 was used instead of the polyamide resin obtained in (1) of Example 1.

Experimental Example 1

[0305] The properties of the individual crystals contained in the polyamide resins obtained in Examples, Comparative Examples were measured by the following method using a small-angle X-ray scattering method (SAXS), and the results are shown in Table 1 below.

[0306] The polymer films obtained in Examples and Comparative Examples were used to prepare a sample with a size of 1 cm in width*1 cm in length. The sample was set on a small angle X-ray scattering apparatus (PLS-9A USAXS beam line) having a camera length of 2.5 m, 6.5 m at room temperature (23° C.), and irradiated with X-rays having an energy of 11.1 KeV, 19.9 KeV to obtain a scattering pattern. The scattering pattern was analyzed through the analysis equipment (NIST SANS package) mounted on the small angle X-ray scattering apparatus to determine the average particle size (2Rc), dimensionality, and crystallinity of the individual crystals.

[0307] Specifically, the analysis of the average particle size (2Rc), dimensionality, and crystallinity of the individual crystals was performed through a computer program (NIST SANS package) using the data obtained from a small angle X-ray scattering apparatus (PLS 9A beamline). More specifically, the average particle size of the individual crystals can be obtained through the calculation of computer program (NIST SANS package) for the diameter distribution curve of crystals which is obtained by fitting the shape of individual crystals contained in the sample to a solid sphere model, plotting the obtained wavenumber q (unit: Å.sup.−1) and scattering intensity I (unit: a.u.), and convoluting the plot with a Schulz-Zimm distribution.

TABLE-US-00001 TABLE 1 Average particle size of Degree of crystal- crystals (nm) Dimensionality linity (%) Example 1 5.0 3.7 Difficult to measure at less than 20% Example 2 6.8 — Difficult to measure at less than 20% Comparative 8.4 4.0 Difficult to measure Example 1 at less than 20% Comparative 13.4 3.2 24 Example 2 Comparative 8.1 — Difficult to measure Example 3 at less than 20%

[0308] As shown in Table 1. it could be confirmed that the average particle size of the individual crystals contained in the polyamide resin obtained in Examples was measured to be as small as 5 nm to 6.8 nm, whereas the average particle size of the individual crystals contained in the polyamide resin obtained in Comparative Example 1 was 8.4 nm, the average particle size of the individual crystals contained in the polyamide resin obtained in Comparative Example 2 was 13.4 nm, and the average particle size of the individual crystals contained in the polyamide resin obtained in Comparative Example 3 was 8.1 nm, which increased as compared to Examples. In addition, it was confirmed that the crystallinity of the polyamide resin obtained in Examples showed a low degree of crystallinity of less than 20%. while the degree of crystallinity of the polyamide resin obtained in Comparative Example 2 was 24%, which increased compared to Examples.

[0309] Thereby, it was confirmed that in the case of the polyamide resin obtained in Examples, the growth of the length of the crystalline block consisting of a repeating unit obtained by an amide reaction of terephthaloyl chloride (TPC) and 2,2′-bis(trifluoromethyl)-4,4′-biphenyldiamine (TFDB) was suppressed compared with Comparative Examples.

Experimental Example 2

[0310] A graph of the small-angle X-ray scattering function I(q) of the polyamide resins obtained in Examples and Comparative Examples using a small-angle X-ray scattering method (SAXS) is shown in FIG. 4 below.

[0311] The graph of the small-angle X-ray scattering function I(q) was obtained by transmitting X-rays to the sample from u-SAXS beam-line 9A at Pohang light source laboratory and measuring the scattering intensity according to the wavenumber q.

[0312] Specifically, the polymer films obtained in Examples and Comparative Examples were used to prepare a sample with a size of 1 cm in width*1 cm in length*50 μm in thickness. The sample was set on a small angle X-ray scattering apparatus (PLS-9A u-SAXS beam line 9A) having a camera length of 2.5 m, 6.5 m at room temperature (23° C.), and irradiated with X-rays having an energy of 11.1 KeV (6.5 m from sample), 19.9 KeV (2.5 m from sample). Two-dimensional images were obtained through a 2D CCD detector (manufactured by Rayonix SX165), averaged into a circle based on the beam stop and converted into a one-dimensional image. Two data were merged using the NIST SANS data reduction package.

[0313] Then, it was fitted to a solid sphere model using the NIST SANS package, which is a computer program. A graph of the function I(q) (wavenumber range of 0.0024 Å.sup.−1 to 0.5 Å.sup.−1) whose X axis is the wavenumber q (unit: Å.sup.−1), and Y-axis is the scattering intensity I (unit: a.u.) was obtained using P. Grady's Excel program.

[0314] As shown in FIG. 4 below, it was confirmed that the small-angle X-ray scattering function I(q) of the polyamide resins obtained in Examples 1 and 2 had a downward convex curve profile at 0.003 Å.sup.−1≤q≤0.03 Å.sup.−1, had an intensity of about 10 a.u. at 0.08 Å.sup.−1≤q and an intensity of about 8000 a.u. at q=0.003 Å.sup.−1.

[0315] On the other hand, it was confirmed that the small-angle X-ray scattering profile of the polyamide resin obtained in Comparative Example 1 had a downward convex curve profile at 0.003 Å.sup.−1≤q≤0.03 Å.sup.−1, but had an intensity of about 0.01 a.u. at 0.08 Å.sup.−1≤q and an intensity of about 80 a.u. at q=0.003 Å.sup.−1, which were different from Example 1.

[0316] Further, it was confirmed that the small-angle X-ray scattering profile of the polyamide resin obtained in Comparative Example 2 had an upward convex curve profile at 0.003 Å.sup.−1≤q≤0.03 Å.sup.−1, and had an intensity of about 0.1 a.u. at 0.08 Å.sup.−1≤q and an intensity of about 200 a.u. at q=0.003 Å.sup.−1, which were different from Example 1.

Experimental Example 3

[0317] The following characteristics were measured or evaluated for the polyamide resins or the polymer films obtained in the above examples and comparative examples, and the results are shown in Table 2 below.

[0318] (1) Thickness: The thickness of the polymer film was measured using a thickness measuring device.

[0319] (2) Yellowness index (Y.I.): The yellowness index of the polymer film was measured according to the measurement method of ASTM E313 using a COH-400 Spectrophotometer (NIPPON DENSHOKU INDUSTRIES).

[0320] (3) Transmittance: The total light transmittance of the polymer film was measured using a Shimadzu UV-2600 UV-vis spectrometer. In the measurement results, the transmittance (T, @388 nm) for ultraviolet light at a wavelength of 388 nm and the transmittance (T, @550 nm) for visible light at wavelength of 550 nm were shown.

[0321] (4) Haze: The haze value of the polymer film was measured according to the ASTM D1003 test method using a COH-400 Spectrophotometer (NIPPON DENSHOKU INDUSTRIES).

[0322] (5) Molecular weight and polydispersity index (PDI): The weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polyamide resin were measured by gel permeation chromatography (GPC, manufactured by Waters), and the polydispersity index (PDI) was calculated by dividing the weight average molecular weight by the number average molecular weight. Specifically, the measurement was performed using a 600 mm long column connecting two Polymer Laboratories PLgel MIX-B Columns (300 mm in length), through Waters 2605 Refractive Index (RI) Detector, wherein the evaluation temperature was 50 to 75° C. (about 65° C.), DMF 100 wt % solvent was used, the flow rate was 1 mL/min, and the sample was prepared at a concentration of 1 mg/mL and supplied in an amount of 100 μL for 25 minutes. The molecular weights could be determined using calibration curves formed using polystyrene standards. As the molecular weight of polystyrene standard products, 7 types of 3940/9600/31420/113300/327300/1270000/4230000 were used.

[0323] (6) Bending Property: The folding endurance of the polymer films was evaluated using an MIT type folding endurance tester. Specifically, a specimen (1 cm*7 cm) of the polymer film was loaded into the folding endurance tester, and folded to an angle of 135° at a rate of 175 rpm on the left and right sides of the specimen, with a radius of curvature of 0.8 mm and a load of 250 g, until the specimen was bended and fractured. The number of reciprocating bending cycles was measured as the folding endurance.

[0324] (7) Viscosity: Under a constant reflux system at 25±0.2° C., the viscosity of the solution containing polyamide resin (solvent: dimethylacetamide (DMAc), solid content: 10 wt %) was measured according to ASTM D 2196: test method of non-Newtonian materials by Brookfield DV-2T Rotational Viscometer. As Brookfield silicone standard oil, a number of standard solutions having a viscosity range of 5000 cps to 200000 cps was used. The measurement was performed with a spindle LV-4 (64), 0.3-100 RPM, and the unit was cps (mPa.Math.s).

[0325] (8) Pencil Hardness: The pencil hardness of the polymer films was measured according to the ASTM D3363 test method using a Pencil Hardness Tester. Specifically, varying hardness values of pencils were fixed to the tester and scratched on the polymer film, and the degree of occurrence of a scratch on the polymer film was observed with the naked eye or with a microscope. When more than 70% of the total number of scratches were not observed, a value corresponding to the hardness of the pencil was evaluated as the pencil hardness of the polymer film.

[0326] The pencil hardness is increased in the order of B grade, F grade and H grade. Within the same grade, the higher the number, the higher the hardness. Within the grade, the higher the number, the higher the hardness.

[0327] (9) UV-cut off wavelength (λ) and UV-cut slope (dT/dλ): The UV-cut off wavelength (λ) and UV-cut slope (dT/dλ) of the polyamide resin film were measured according to the ASTM E424 test method 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%.

TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Category Example 1 Example 2 Example 1 Example 2 Example 3 Thickness (μm) 50 49 51 51 50 Y.I. 2.68 2.89 8.55 25.10 4.59 T (%)@550 nm 88.75 88.50 85.63 75.94 87.57 T (%)@388 nm 75.3 71.0 51.01 31.62 65.04 Haze(%) 0.81 0.97 3.43 24.21 1.61 Mw(g/mol) 512000 463000 412000 350000 382000 Bending 12022 9785 5210 785 4513 property (Cycle) PDI 1.84 2.71 2.05 2.02 1.98 Viscosity 110000 174000 54000 24000 28000 (cps) Pencil hardness 3H 4H 1H F 1H UV-cut slope 2.90 2.45 — — — (dT/dλ)@10% UV-cut slope 0.36 0.68 — — — (dT/dλ)@80% UV-cut slope 4.56 3.67 — — — (dT/dλ) Maximum value@10~80% UV-cut 0.35 0.68 — — — slope(dT/dλ) Minimum value@10~80%

[0328] Looking at Table 2 above, the polyamide resin of Examples prepared using the acyl chloride complex powder according to Preparation Examples 1 to 2 had a high weight average molecular weight of 463000 g/mol to 512000 g/mol, and the relative viscosity was measured to be as high as 110000 cps to 174000 cps. Moreover, it was confirmed that the polymer film obtained from the polyamide resin of Examples had a low yellowness index of 2.68 to 2.89 and a low haze value of 0.81% to 0.97% at a thickness of about 50 μm, thereby exhibiting excellent transparency. It was also confirmed that it had a high pencil hardness of 3H to 4H grade and a folding endurance that was broken at the number of reciprocating bending cycles from 9785 to 12022, thereby securing excellent mechanical properties (scratch resistance and folding endurance).

[0329] In addition, it was confirmed that it had a high UV-cut slope of 0.35 or more in the range of 10% to 80% transmittance, thereby realizing excellent UV shielding function.

[0330] On the other hand, in the case of the polyamide resins of Comparative Examples in which the acyl chloride complex powder according to Preparation Examples 1 to 2 was not used in the synthesis process of the polyamide resin, the molecular weight was reduced from 350,000 g/mol to 412,000 g/mol compared to Examples. The viscosity was reduced from 24,000 cps to 54,000 cps compared to Examples.

[0331] On the other hand, in the case of the polymer films obtained from the polyamide resins of Comparative Examples 1, 2, and 3 in which TPC powder and IPC powder were simultaneously or sequentially added, it was confirmed that the films had a yellowness index of 4.59 to 25.10 and a haze value of 1.61% to 24.21% at a thickness of about 50 μm, which increased compared to Examples, resulting in poor transparency. This is considered to be because, in Comparative Examples 1, 2, and 3, due to the difference in solubility and reactivity between the TPC powder and the IPC powder, the block due to TPC is excessively formed, thereby increasing the crystallinity of the polyamide resin.

EXPLANATION OF SYMBOLS

[0332] 1: individual crystals [0333] 2: average particle size of individual crystals [0334] 3: amorphous polymer chain