Patent Description:
Aromatic polyimide resins are polymers mostly having an amorphous structure, and exhibits excellent heat resistance, chemical resistance, electrical properties, and dimensional stability due to their rigid chain structure. Thus, these polyimide resins are widely used as materials for electric/electronics.

However, the polyimide resins have many limitations in their use because they may appear dark brown in color due to charge transfer complex (CTC) formation of Pi-electrons present in the imide chain, and it is difficult to secure transparency. In the case of the polyimide film including the same, it has a drawback in that the surface is easily scratched and scratch resistance is very weak.

In order to solve the above limitation of the polyimide resin, studies on polyamide resins into which an amide group is introduced has been actively conducted. The amide structure induces intermolecular or intramolecular hydrogen bonds, resulting in improvement of scratch resistance by interactions such as hydrogen bonds.

However, due to the difference in solubility, reactivity (steric hindrance), and reaction rate of terephthaloyl chloride or isophthaloyl chloride used for the synthesis of the polyamide resin, amide repeating units derived from terephthaloyl chloride and amide repeating units derived from isophthaloyl chloride do not form a block, and are hardly polymerized ideally or alternatively.

Therefore, there is a limit that as the block of amide repeating units derived from the para acyl chloride monomer is formed and the crystallinity of the polyamide resin increases, the transparency becomes poor due to haze.

In addition, as the monomers used for the synthesis of the polyamide resin perform the polymerization reaction in a state dissolved in a solvent, the molecular weight of the finally synthesized polyamide resin is difficult to be ensured to a sufficient level due to deterioration by moisture or hybridization with a solvent.

Accordingly, there is a continuing need to develop a polyamide resin capable of realizing transparency and mechanical properties simultaneously.

<CIT> describes a polyamide film which is stretched in two directions of a longitudinal direction and a width direction and has a refractive index of <NUM> or more in both directions.

<CIT> relates to a polyamide having at least an alicyclic or aromatic group exhibiting a light transmittance of <NUM> % or more in the wavelength region of <NUM> to <NUM> being produced by using an aramide polymer comprising specific structural units at an amount of <NUM> mol% or more.

<CIT> provides a polyamide-imide film which maintains transparency and has highly enhanced mechanical properties and heat resistance.

It is an object of the present invention to provide a polyamide resin that can secure at least an adequate level of mechanical properties while improving transparency by suppressing excessive growth of the length of crystalline polymer chains.

It is another object of the present invention to provide a polymer film and resin laminate using the aforementioned polyamide resin.

In order to achieve above objects, one aspect of the present invention provides a polyamide resin in which an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus is <NUM> or less, wherein.

Hereinafter, a polyamide resin and a polymer film and resin laminate using the same according to specific embodiments of the present invention will be described in more detail.

Unless explicitly stated otherwise, the terminology used herein may be defined as follows.

Throughout the specification, when one part "includes" one constituent element, unless otherwise specifically described, this does not mean that another constituent element is excluded, but means that another constituent element may be further included.

In the present specification, examples of the substituents are described below, but are not limited thereto.

As used herein, the term "substituted" means that other functional groups instead of a hydrogen atom in the compound are bonded, and a position to be substituted is not limited as long as the position is a position at which the hydrogen atom is substituted, that is, a position at which the substituent can be substituted, and when two or more are substituted, the two or more substituents may be the same as or different from each other.

As used herein, the term "substituted or unsubstituted" means being unsubstituted or substituted with one or more substituents selected from the group consisting of deuterium; a halogen group; a cyano group; a nitro group; a hydroxyl group; a carbonyl group; an ester group; an imide group; an amide group; a primary amino group; a carboxy group; a sulfonic acid group; a sulfonamide group; a phosphine oxide group; an alkoxy group; an aryloxy group; an alkylthioxy group; an arylthioxy group; an alkylsulfoxy group; an arylsulfoxy group; a silyl group; a boron group; an alkyl group; a haloalkyl group; a cycloalkyl group; an alkenyl group; an aryl group; an aralkyl group; an aralkenyl group; an alkylaryl group; an alkoxysilylalkyl group; an arylphosphine group; or a heterocyclic group containing at least one of N, O, and S atoms, or being unsubstituted or substituted with a substituent to which two or more substituents are linked among the substituents exemplified above. For example, "the substituent to which two or more substituents are linked" may be a biphenyl group. That is, the biphenyl group may also be an aryl group, and may be interpreted as a substituent to which two phenyl groups are linked. Preferably, a haloalkyl group can be used as the substituent, and examples of the haloalkyl group include trifluoromethyl group.

As used herein, the notation <IMG>, or <IMG> means a bond linked to another substituent group, and a direct bond means the case where no other atoms exist in the parts represented as L.

In the present specification, the alkyl group is a monovalent functional group derived from an alkane, and may be a straight-chain or a branched-chain. The number of carbon atoms of the straight chain alkyl group is not particularly limited, but is preferably <NUM> to <NUM>. Also, the number of carbon atoms of the branched chain alkyl group is <NUM> to <NUM>. Specific examples of the alkyl group include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, <NUM>-methyl-butyl, <NUM>-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, <NUM>-methylpentyl, <NUM>-methylpentyl, <NUM>-methyl-<NUM>-pentyl, <NUM>,<NUM>-dimethylbutyl, <NUM>-ethylbutyl, heptyl, n-heptyl, <NUM>-methylhexyl, octyl, n-octyl, tert-octyl, <NUM>-methylheptyl, <NUM>-ethylhexyl, <NUM>-propylpentyl, n-nonyl, <NUM>,<NUM>-dimethylheptyl, <NUM>-ethyl-propyl, <NUM>,<NUM>-dimethyl-propyl, isohexyl, <NUM>-methylpentyl, <NUM>-methylhexyl, <NUM>-methylhexyl, <NUM>,<NUM>-dimethylheptane-<NUM>-yl and the like, but are not limited thereto.

In the present specification, the aryl group is a monovalent functional group derived from an arene, and is not particularly limited, but preferably has <NUM> to <NUM> carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. The monocyclic aryl group may include, but not limited to, a phenyl group, a biphenyl group, a terphenyl group, or the like. The polycyclic aryl group may include, but not limited to, a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, a fluorenyl group or the like. The aryl group may be substituted or unsubstituted.

In the present specification, the arylene group is a bivalent functional group derived from an arene, and the description of the aryl group as defined above may be applied, except that it is a divalent functional group. For example, it may be a phenylene group, a biphenylene group, a terphenylene group, a divalent naphthalene group, a divalent fluorenyl group, a divalent pyrenyl group, a divalent phenanthrenyl group, a divalent perylene group, a divalent tetracenyl group, an divalent anthracenyl group and the like. The arylene group may be substituted or unsubstituted.

In the present specification, a heteroaryl group includes one or more atoms other than carbon, that is, one or more heteroatoms, and specifically, the heteroatom may include one or more atoms selected from the group consisting of O, N, Se, and S, and the like. The number of carbon atoms thereof is not particularly limited, but is preferably <NUM> to <NUM>, and the heteroaryl group may be monocyclic or polycyclic. Examples of a heterocyclic group include a thiophene group, a furanyl group, a pyrrole group, an imidazolyl group, a thiazolyl group, an oxazolyl group, an oxadiazolyl group, a pyridyl group, a bipyridyl group, a pyrimidyl group, a triazinyl group, a triazolyl group, an acridyl group, a pyridazinyl group, a pyrazinyl group, a quinolinyl group, a quinazolinyl group, a quinoxalinyl group, a phthalazinyl group, a pyridopyrimidinyl group, a pyridopyrazinyl group, a pyrazinopyrazinyl group, an isoquinolinyl group, an indolyl group, a carbazolyl group, a benzoxazolyl group, a benzimidazolyl group, a benzothiazolyl group, a benzocarbazolyl group, a benzothiophene group, a dibenzothiophene group, a benzofuranyl group, a phenanthrolinyl group (phenanthroline), a thiazolyl group, an isoxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a benzothiazolyl group, a phenothiazinyl group, an aziridinyl group, an azaindolyl group, an isoindolyl group, an indazolyl group, a purine group (purine), a pteridinyl group (pteridine), a beta-carboline group, a naphthyridinyl group (naphthyridine), a ter-pyridyl group, a phenazinyl group, an imidazopyridyl group, a pyropyridyl group, an azepine group, a pyrazolyl group, a dibenzofuranyl group, and the like, but are not limited thereto. The heteroaryl group may be substituted or unsubstituted.

In the present specification, the hetero arylene group has <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM> carbon atoms. For the arylene group containing O, N or S as a hetero atom, the description of the heteroaryl group as defined above can be applied except that it is a divalent functional group. The hetero arylene group may be substituted or unsubstituted.

In this specification, examples of halogen include fluorine, chlorine, bromine or iodine.

According to one embodiment of the present invention, there can be provided a polyamide resin in which an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus is <NUM> or less, wherein.

The present inventors have found through experiments that as the polyamide resin in which an average particle size of individual crystals is <NUM> or less as described above not only has excellent mechanical properties possessed by a crystalline polymer but also the growth of individual crystals forming the crystal structure slows down to have a relatively small size, whereby it has a remarkably low level of haze value, yellowness, etc., and additionally can have high flexibility and bending durability, thereby completing the present invention.

Unlike this, when the average particle size of individual crystals measured for the polyamide resin by a small-angle X-ray scattering apparatus increases excessively to <NUM> or more, the ratio occupied by the portion having crystallinity in the polyamide resin or the size thereof is excessively grown, whereby the crystal characteristic is strongly implemented, the flexibility or bending durability of the polymer itself is lowered, the haze value is rapidly increased and so the transparency can be lowered.

Specifically, the polyamide resin can satisfy an average particle size of individual crystals of <NUM> or less as measured by a small-angle X-ray scattering apparatus. The polyamide resin may include a plurality of individual crystals. The average particle size of the individual crystals contained in the polyamide resin can be determined through the method for calculating the number average particle size which includes confirming the particle sizes of all the crystals contained in the polyamide resin and then dividing the sum of these particle sizes by the number of individual crystals.

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 <NUM> KeV to <NUM> KeV in a small-angle X-ray scattering apparatus to a solid sphere model.

As for the X-rays to be irradiated, for example, a method of irradiating X-rays with energies of <NUM> KeV to <NUM> KeV and X-rays together with energies of <NUM> KeV to <NUM> KeV can be used.

The scattering pattern, which is the data obtained from the small-angle X-ray scattering apparatus, may be a result measured by irradiating X-rays with energies of <NUM> KeV to <NUM> KeV using the small-angle X-ray scattering apparatus at a temperature of <NUM> to <NUM>. As a detector in the small-angle X-ray scattering apparatus, an imaging plate, a position-sensitive detector (PSPC), and the like can be used.

Subsequently, an average particle size analysis of the individual crystals may be performed through an analytical equipment that is separately installed inside or outside the small-angle X-ray scattering apparatus. An example of the small-angle X-ray scattering apparatus may be a PLS 9A beamline, and an example of the analytical equipment may be a NIST SANS package which is a computer program.

Specifically, the average particle size of the individual crystals can be determined 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-<NUM>) and scattering intensity I (unit: a. ), and convoluting the plot with a Schulz-Zimm distribution.

The crystals can be a group of individual crystals having a particle size of <NUM> to <NUM>, and the individual crystals contained in such group can have an average particle size of <NUM> or less. More specifically, <NUM>%, or <NUM>% of the individual crystals contained in the group may have a particle size of <NUM> or less. That is, as the majority of the individual crystals has a particle size of <NUM> or less, or <NUM> or less, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, the average particle size of the individual crystals may also satisfy the above-mentioned range.

More specifically, the average particle size of the individual crystals measured by the small-angle X-ray scattering apparatus may be <NUM> or less, or <NUM> or less, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, Or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>.

Specifically, when the polyamide resin sample is irradiated with X-rays using the small-angle X-ray scattering apparatus, the small-angle X-ray scattering pattern is secured through a detector. When analyzing this through an analytical equipment, it is possible to determine the average radius (Rc) of the individual crystals contained in the polyamide resin sample. Through this, finally, the average particle size of the individual crystals can be determined by calculating twice the average radius (Rc) of the individual crystals described above.

More specifically, with reference to the crystal structure of the polyamide resin of one embodiment described in <FIG> below, the polyamide resin is composed of amorphous polymer chains <NUM> present between individual crystals, together with a plurality of individual crystals <NUM>, and a particle size <NUM> can be defined for the individual crystals.

On the other hand, the individual crystals <NUM> may be formed by gathering polyamide resin chains in a bundle, as shown in the schematic diagram below. In particular, the length of the individual crystals can be grown through the overlap between the crystalline polymer blocks contained in the polyamide resin. It is difficult to specifically specify the shape of the overlapped individual crystals, but it can be seen that it has roughly a spherulite structure by three-dimensional growth, a lamella structure by two-dimensional growth, or an intermediate structure between three-dimensional and two-dimensional.

Preferably, the polyamide resin may have a dimensionality of the individual crystals measured by a small-angle X-ray scattering apparatus of <NUM> or more, or <NUM> to <NUM>. The dimensionality of the individual crystals of the polyamide resin can be measured through an analytical instrument by fitting a spherical scattering pattern obtained by irradiating X-rays with energies of <NUM> KeV to <NUM> KeV, or <NUM> KeV to <NUM> KeV, or <NUM> KeV to <NUM> KeV in a small-angle X-ray scattering apparatus to a solid sphere model. The small-angle X-ray scattering apparatus and the contents of the analysis thereon include the contents described above in the average particle size of the individual crystals.

Meanwhile, the polyamide resin further includes amorphous polymer chains present between the individual crystals having an average particle size of <NUM> or less. More specifically, with reference to the crystal structure of the polyamide resin of one embodiment described in <FIG> below, the polyamide resin may be composed of amorphous polymer chains <NUM> present between individual crystals together with a plurality of individual crystals <NUM>.

Due to the amorphous polymer chains, the growth of the average particle size of the individual crystals is suppressed, and the polyamide resin may satisfy an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus of <NUM> or less.

In this case, the distance between the individual crystals having an average particle size of <NUM> or less may be <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>. The distance between individual crystals having an average particle size of <NUM> or less can also be measured by a small-angle X-ray scattering apparatus.

In the polyamide resin, examples of specific components of the individual crystals whose average particle size measured by a small-angle X-ray scattering apparatus is <NUM> or less are not particularly limited, and various aromatic amide repeating units used in the preparation of crystalline polyamide resins can be applied without limitation.

As an example of the component of the individual crystals whose average particle size measured by the small-angle X-ray scattering apparatus is <NUM> or less, a first aromatic amide repeating unit derived from a combination of a <NUM>,<NUM>-aromatic diacyl compound and an aromatic diamine compound may be included. The polymer chains composed of the first aromatic amide repeating units may be gathered in a bundle to form individual crystals having an average particle size of <NUM> or less.

Specific examples of the <NUM>,<NUM>-aromatic diacyl compound include terephthaloyl chloride or terephthalic acid. In addition, examples of the aromatic diamine monomer may include at least one selected from the group consisting of <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobenzidine, <NUM>,<NUM>'-diaminodiphenyl sulfone, <NUM>,<NUM>'-(<NUM>-fluorenylidene)dianiline, bis(<NUM>-(<NUM>-aminophenoxy)phenyl)sulfone, <NUM>,<NUM>',<NUM>,<NUM>'-tetrachlorobenzidine, <NUM>,<NUM>-diaminofluorene, <NUM>,<NUM>-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, <NUM>,<NUM>'-oxydianiline, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobiphenyl, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, m-xylylenediamine, p-xylylenediamine and <NUM>,<NUM>'-diaminobenzanilide.

Preferably the <NUM>,<NUM>-aromatic diacyl compound may include terephthaloyl chloride, or terephthalic acid, and the aromatic diamine compound may include <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine.

More specifically, the individual crystals having an average particle size of <NUM> or less include a first polyamide segment including a repeating unit represented by the following Chemical Formula <NUM>, or a block comprised thereof. <CHM>
in Chemical Formula <NUM>, Ar<NUM> is a substituted or unsubstituted arylene group having <NUM> to <NUM> carbon atoms, or a substituted or unsubstituted heteroarylene group having <NUM> to <NUM> carbon atoms.

In Chemical Formula <NUM>, Ar<NUM> is an arylene group having <NUM> to <NUM> carbon atoms that is substituted with one or more substituents selected from the group consisting of an alkyl group, a haloalkyl group, and an amino group, and more preferably, it may be a <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenylene group.

More specifically, in Chemical Formula <NUM>, Ar<NUM> may be a divalent organic functional group derived from an aromatic diamine monomer, and specific examples of the aromatic diamine monomer may include at least one selected from the group consisting of <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobenzidine, <NUM>,<NUM>'-diaminodiphenyl sulfone, <NUM>,<NUM>'-(<NUM>-fluorenylidene)dianiline, bis(<NUM>-(<NUM>-aminophenoxy)phenyl)sulfone, <NUM>,<NUM>',<NUM>,<NUM>'-tetrachlorobenzidine, <NUM>,<NUM>-diaminofluorene, <NUM>,<NUM>-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, <NUM>,<NUM>'-oxydianiline, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobiphenyl, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, and <NUM>,<NUM>'-diaminobenzanilide. More preferably, the aromatic diamine monomer may be <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine(TFDB) or <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobenzidine.

The first polyamide segment includes a repeating unit represented by Chemical Formula <NUM>, or a block composed of a repeating unit represented by Chemical Formula <NUM>.

Specific examples of the repeating unit represented by Chemical Formula <NUM> include a repeating unit represented by the following Chemical Formula <NUM>-<NUM>.

The repeating unit represented by Chemical Formula <NUM> is an amide repeating unit derived from a combination of a <NUM>,<NUM>-aromatic diacyl compound and an aromatic diamine compound, specifically, an amide repeating unit formed by an amidation reaction of terephthaloyl chloride or terephthalic acid with an aromatic diamine monomer. Due to the linear molecular structure, the chain packing and alignment can be kept constant in the polymer, and the surface hardness and mechanical properties of the polyamide film can be improved.

Specific examples of the <NUM>,<NUM>-aromatic diacyl compound include terephthaloyl chloride or terephthalic acid. In addition, examples of the aromatic diamine monomer may include at least one selected from the group consisting of <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine), <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobenzidine, <NUM>,<NUM>'-diaminodiphenyl sulfone, <NUM>,<NUM>'-(<NUM>-fluorenylidene)dianiline, bis(<NUM>-(<NUM>-aminophenoxy)phenyl)sulfone), <NUM>,<NUM>',<NUM>,<NUM>'-tetrachlorobenzidine, <NUM>,<NUM>-diaminofluorene, <NUM>,<NUM>-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, <NUM>,<NUM>'-oxydianiline, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobiphenyl, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, m-xylylenediamine, p-xylylenediamine and <NUM>,<NUM>'-diaminobenzanilide.

The first polyamide segment may have a number average molecular weight of <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol. When the number average molecular weight of the first polyamide segment is increased to more than <NUM>/mol, the chains of the first polyamide segment become excessively long and so the crystallinity of the polyamide resin can be increased. As a result, it may have a high haze value and so it may be difficult to secure transparency. Examples of the measuring method of the number average molecular weight of the first polyamide segment is not limited, but for example, it can be confirmed through a small-angle X-ray scattering (SAXS) analysis.

The first polyamide segment may be represented by the following Chemical Formula <NUM>. <CHM>
in Chemical Formula <NUM>, Ar<NUM> is a substituted or unsubstituted arylene group having <NUM> to <NUM> carbon atoms, or a substituted or unsubstituted heteroarylene group having <NUM> to <NUM> carbon atoms, and a is an integer of <NUM> to <NUM>. In Chemical Formula <NUM>, when a is <NUM>, the Formula <NUM> may be a repeating unit represented by Chemical Formula <NUM>. In Chemical Formula <NUM>, when a is <NUM> to <NUM>, the Formula <NUM> may be a block composed of repeating units represented by Chemical Formula <NUM>. In Chemical Formula <NUM>, the details concerning Ar<NUM> includes those described above in Chemical Formula <NUM>.

Based on the total repeating units contained in the polyamide resin, the ratio of the repeating units represented by Chemical Formula <NUM> is <NUM> mol% to <NUM> mol%, preferably, <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%.

In this manner, the polyamide resin in which the repeating unit represented by Chemical Formula <NUM> is contained in the above-described content can ensure a sufficient level of molecular weight, thereby ensuring excellent mechanical properties.

Further, in the polyamide resin, examples of specific components of the amorphous polymer chains present between the individual crystals having an average particle size of <NUM> or less are not particularly limited, and various aromatic amide repeating units used in the preparation of amorphous polyamide resins can be applied without limitation.

Examples of an amorphous polymer chain component present between individual crystals whose average particle size measured by the small-angle X-ray scattering apparatus is <NUM> or less may include a second aromatic amide repeating units derived from a combination of a <NUM>,<NUM>-aromatic diacyl compound and an aromatic diamine compound, or a third aromatic amide repeat unit derived from a combination of a <NUM>,<NUM>-aromatic diacyl compound and an aromatic diamine compound, or mixtures thereof. The polymer chains composed of the second aromatic amide repeating unit or the third aromatic amide repeating unit as described above may realize amorphous characteristics.

Specific examples of the <NUM>,<NUM>-aromatic diacyl compound include phthaloyl chloride or phthalic acid. In addition, specific examples of the <NUM>,<NUM>-aromatic diacyl compound include isophthaloyl chloride or isophthalic acid. Examples of the aromatic diamine monomer include at least one selected from the group consisting of <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'- diaminobenzidine, <NUM>,<NUM>'-diaminodiphenyl sulfone, <NUM>,<NUM>'-(<NUM>-fluorenylidene)dianiline, bis(<NUM>-(<NUM>-aminophenoxy)phenyl)sulfone, <NUM>,<NUM>',<NUM>,<NUM>'-tetrachlorobenzidine, <NUM>,<NUM>-diaminofluorene, <NUM>,<NUM>-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, <NUM>,<NUM>'-oxydianiline, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobiphenyl, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, m-xylylenediamine, p-xylylenediamine and <NUM>,<NUM>'-diaminobenzanilide.

Preferably the <NUM>,<NUM>-aromatic diacyl compound may include phthaloyl chloride, or phthalic acid, the <NUM>,<NUM>-aromatic diacyl compound may include isophthaloyl chloride or isophthalic acid, and the aromatic diamine compound may include <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine.

The amorphous polymer chains present between the individual crystals having an average particle size of <NUM> or less including the first polyamide segment including a repeating unit represented by Chemical Formula <NUM> or a block composed thereof include a second polyamide segment including a repeating unit represented by the following Chemical formula <NUM>, or a block composed thereof. <CHM>
in Chemical Formula <NUM>, Ar<NUM> is a substituted or unsubstituted arylene group having <NUM> to <NUM> carbon atoms, or a substituted or unsubstituted heteroarylene group having <NUM> to <NUM> carbon atoms.

In Chemical Formula <NUM>, Ar<NUM> is an arylene group having <NUM> to <NUM> carbon atoms that is substituted with one or more substituents selected from the group consisting of an alkyl group, a haloalkyl group, and an amino group. More preferably, it may be a <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenylene group.

More specifically, in Chemical Formula <NUM>, Ar<NUM> may be a divalent organic functional group derived from an aromatic diamine monomer. Specific examples of the aromatic diamine monomer include at least one selected from the group consisting of <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'- diaminobenzidine, <NUM>,<NUM>'-diaminodiphenyl sulfone, <NUM>,<NUM>'-(<NUM>-fluorenylidene)dianiline, bis(<NUM>-(<NUM>-aminophenoxy)phenyl)sulfone, <NUM>,<NUM>',<NUM>,<NUM>'-tetrachlorobenzidine, <NUM>,<NUM>-diaminofluorene, <NUM>,<NUM>-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, <NUM>,<NUM>'-oxydianiline, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobiphenyl, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, and <NUM>,<NUM>'-diaminobenzanilide. More preferably, the aromatic diamine monomer may be <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine (TFDB) or <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobenzidine.

The second polyamide segment includes a repeating unit represented by Chemical Formula <NUM>, or a block composed of the repeating unit represented by Chemical Formula <NUM>.

More specifically, the repeating unit represented by Chemical Formula <NUM> may include one type of repeating unit selected from a repeating unit represented by the following Chemical Formula <NUM>-<NUM>; or a repeating unit represented by Chemical Formula <NUM>-<NUM>. <CHM>
<CHM>
in Chemical Formulas <NUM>-<NUM> to <NUM>-<NUM>, Ar<NUM> is a substituted or unsubstituted arylene group having <NUM> to <NUM> carbon atoms, or a substituted or unsubstituted heteroarylene group having <NUM> to <NUM> carbon atoms. The details concerning Ar<NUM> includes those described above in Chemical Formula <NUM>.

The repeating unit represented by Chemical Formula <NUM>-<NUM> is a repeating unit formed by an amidation reaction of isophthaloyl chloride or isophthalic acid with an aromatic diamine monomer, and the repeating unit represented by Chemical Formula <NUM>-<NUM> is a repeating unit formed by an amidation reaction of phthaloyl chloride or phthalic acid with an aromatic diamine monomer.

Specific examples of the repeating unit represented by Chemical Formula <NUM>-<NUM> include a repeating unit represented by the following Chemical Formula <NUM>-<NUM>.

On the other hand, the second polyamide segment may be represented by the following Chemical Formula <NUM>.

In Chemical Formula <NUM>, Ar<NUM> is a substituted or unsubstituted arylene group having <NUM> to <NUM> carbon atoms, or a substituted or unsubstituted heteroarylene group having <NUM> to <NUM> carbon atoms, and b is an integer of <NUM> to <NUM> or <NUM> to <NUM>. In Chemical Formula <NUM>, when b is <NUM>, the Formula <NUM> may be a repeating unit represented by Chemical Formula <NUM>. In Chemical Formula <NUM>, when b is <NUM> to <NUM>, the Formula <NUM> may be a block composed of repeating units represented by Chemical Formula <NUM>.

The repeating unit represented by Chemical Formula <NUM> is a repeating unit formed by an amidation reaction of isophthaloyl chloride, isophthalic acid or phthaloyl chloride, phthalic acid and an aromatic diamine monomer. Due to the curved molecular structure, it has the property of interfering with chain packing and alignment within the polymer, and it is possible to increase the amorphous region in the polyamide resin and thus improve the optical properties and the folding endurance of the polyamide film. In addition, as this is included in the polyamide resin together with the repeating unit represented by Chemical Formula <NUM>, it is possible to increase the molecular weight of the polyamide resin.

Based on the total repeating units contained in the polyamide resin, the ratio of the repeating unit represented by Chemical Formula <NUM> is <NUM> mol% to <NUM> mol%, preferably, <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%.

As described above, the polyamide resin in which the repeating unit represented by Chemical Formula <NUM> is contained in the above-described content can suppress the length growth of the chains consisting of only the specific repeating unit represented by Chemical Formula <NUM> and thus lower the crystallinity of the resin. As a result, it is possible to have a low haze value and thus secure excellent transparency.

More specifically, based on the total repeating units contained in the polyamide resin, the content of the repeating unit represented by Chemical Formula <NUM> is <NUM> mol% to <NUM> mol%, preferably, <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, and the content of the repeating unit represented by Chemical Formula <NUM> is <NUM> mol% to <NUM> mol%, preferably, <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%, or <NUM> mol% to <NUM> mol%.

That is, the polyamide resin can increase the molar content of the repeating unit represented by Chemical Formula <NUM> and thus maximize the effect of improving the surface hardness and mechanical properties of the polyamide film according to the chain packing and alignment within the polymer due to the linear molecular structure of the repeating unit represented by Chemical Formula <NUM>. In addition, although the repeating unit represented by Chemical Formula <NUM> has a relatively low molar content, it may suppress the length growth of the chains consisting of only the specific repeating unit represented by Chemical Formula <NUM>, thereby lowering the crystallinity of the resin. As a result, it is possible to have a low haze value and thus secure excellent transparency.

On the other hand, the first polyamide segment and the second polyamide segment may form a main chain including an alternating-repeating unit represented by the following Chemical Formula <NUM>. That is, the first polyamide segment contained in the individual crystals whose average particle size measured by the small-angle X-ray scattering apparatus is <NUM> or less may form a alternating-repeating unit represented by the following Chemical Formula <NUM> with the second polyamide segment contained in the amorphous polymer chain existing between the individual crystals.

As a result, the polyamide resin of one embodiment has a structure in which a plurality of individual crystals and amorphous polymer chains are repeated, as in the crystal structure shown in <FIG>, and it is possible to suppress the continuous size growth of only individual crystals. Thereby, the individual crystals allow an average particle size measured by a small-angle X-ray scattering apparatus to reduce to <NUM> or less. <CHM>
in Chemical Formula <NUM>, A is the first polyamide segment, and B is the second polyamide segment.

Specifically, in the main chain of the polyamide resin, a first polyamide segment derived from terephthaloyl chloride or terephthalic acid and a second polyamide segment derived from isophthaloyl chloride, isophthalic acid or phthaloyl chloride, phthalic acid may alternately form a polymer chain as shown in Chemical Formula <NUM>. That is, the second polyamide segment is positioned between the first polyamide segments, and may serve to suppress the growth of the length of the first polyamide segment.

The second polyamide segment is included in an amorphous polymer chain present between individual crystals having an average particle size of <NUM> or less, and the first polyamide segment is included in individual crystals having an average particle size of <NUM> or less. Therefore, in the polyamide resin, the amorphous polymer chain may be positioned between individual crystals having an average particle size of <NUM> or less, and may serve to suppress the growth of the size of the individual crystals. This can also be confirmed through the crystal structure shown in <FIG>.

When the size growth of the individual crystals is suppressed in this manner, it is possible to remarkably lower the haze value of the polyamide resin while reducing crystal properties of the individual crystals, thereby achieving excellent transparency.

On the other hand, "in the main chain of the polyamide resin, a first polyamide segment derived from terephthaloyl chloride or terephthalic acid and a second polyamide segment derived from isophthaloyl chloride, isophthalic acid or phthaloyl chloride, phthalic acid may alternately form a polymer chain as shown in Chemical Formula <NUM>" is considered to be due to the formation of a melt-kneaded complex in the preparation method of the polyamide resin of the present invention described hereinafter.

When explanation is made by enumerating concrete examples, the alternating-repeating unit represented by Chemical Formula <NUM> may be a repeating unit represented by the following Chemical Formula <NUM>. <CHM>
in Chemical Formula <NUM>, Ar<NUM> and Ar<NUM> are each independently a substituted or unsubstituted arylene group having <NUM> to <NUM> carbon atoms, or a substituted or unsubstituted heteroarylene group having <NUM> to <NUM> carbon atoms, a1 and a2 are the same as and different from each other and are each independently an integer of <NUM> to <NUM>, or <NUM> to <NUM>, and b1 and b2 are the same as or different from each other and are each independently an integer of <NUM> to <NUM>, or <NUM> to <NUM>.

In Chemical Formula <NUM>, the crystalline polymer block (derived from terephthaloyl chloride or terephthalic acid) having the number of repeating units of a1 or a2 may form individual crystals whose average particle size measured by the small-angle X-ray scattering apparatus is <NUM> or less. In addition, in Chemical Formula <NUM>, the amorphous polymer block (derived from isophthaloyl chloride, isophthalic acid or phthaloyl chloride, phthalic acid) having the number of repeating units of b1 or b2 may form an amorphous polymer chain existing between individual crystals whose average particle size measured by a small-angle X-ray scattering apparatus is <NUM> or less.

That is, the polyamide resin may include a first polyamide segment including a repeating unit represented by Chemical Formula <NUM> or a block composed thereof; and a second polyamide segment including a repeating unit represented by Chemical Formula <NUM>, or a block composed thereof, wherein the first polyamide segment and the second polyamide segment may form a main chain including an alternating repeating unit represented by Chemical Formula <NUM>.

The present inventors have found through experiments that as the average particle size of the individual crystals is reduced to <NUM> or less as in the polyamide resin of one embodiment, it is possible to minimize the growth of the length of the polymer block (hereinafter, referred to as the first polyamide segment) consisting of repeating units derived from terephthaloyl chloride or terephthalic acid in the polyamide resin and lower the crystallinity of the polyamide resin, thus implementing a transparent polyamide resin. The present invention has been completed on the basis of such finding.

Specifically, in the main chain of the polyamide resin, crystalline polymer blocks derived from terephthaloyl chloride or terephthalic acid (hereinafter, referred to as first polyamide segment) and amorphous polymer blocks derived from isophthaloyl chloride, isophthalic acid or phthaloyl chloride, phthalic acid (hereinafter, referred to as second polyamide segment) may alternately form a polymer chain. That is, the second polyamide segment is positioned between the first polyamide segments, and may serve to suppress the growth of the length of the first polyamide segment.

In this case, the first polyamide segment is included in the individual crystals of the polyamide resin to express crystal properties, and the second polyamide segment is included in an amorphous polymer chain between the individual crystals to express amorphous properties.

Therefore, when the length growth of the first polyamide segment is suppressed, the average particle size of the individual crystals measured by a small-angle X-ray scattering apparatus is measured to be relatively small. Since the polyamide resin can remarkably reduce the haze value while reducing the crystal characteristics of the first polyamide segment, it is possible to achieve excellent transparency.

On the contrary, when the length growth suppression effect of the first polyamide segment by the second polyamide segment is reduced, and the length growth of the first polyamide segment proceeds excessively, the average particle size of the individual crystals measured by the small-angle X-ray scattering apparatus is measured to be relatively large, the polyamide resin may have poor transparency while increasing the crystal characteristics of the first polyamide segment and rapidly increasing the haze value.

And yet, the polyamide resin can have a sufficient level of weight average molecular weight, whereby a sufficient level of mechanical properties can also be achieved.

Meanwhile, the polyamide resin may have a degree of crystallinity of <NUM>% or less, or <NUM>% to <NUM>%, as measured by a small-angle X-ray scattering apparatus. The degree of crystallinity of the polyamide resin can be measured through an analytical instrument by fitting a scattering pattern obtained by irradiating X-rays with energies of <NUM> KeV to <NUM> KeV, or <NUM> KeV to <NUM> KeV, or <NUM> KeV to <NUM> KeV in a small-angle X-ray scattering apparatus to a solid sphere model. The small-angle X-ray scattering apparatus and the analysis contents thereof include the contents described above in the average particle size of the individual crystals.

The weight average molecular weight of the polyamide resin may be <NUM>/mol or more, <NUM>/mol or more, or <NUM>/mol or more, or <NUM>/mol to <NUM> / mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol.

The reason why the weight average molecular weight of the polyamide resin is measured to be high is considered to be due to the formation of a melt-kneaded complex in the preparation method of the polyamide resin of another embodiment of the present invention described hereinafter. When the weight average molecular weight is reduced to less than <NUM>,<NUM>/mol, the polyamide resin has a problem that mechanical properties such as flexibility and pencil hardness are lowered.

The polydispersity index of the polyamide resin may be <NUM> or less, or <NUM> or less, or <NUM> or less, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>. Through such narrow range of polydispersity index, the polyamide resin can improve mechanical properties such as bending properties or hardness properties. When the polydispersity index of the polyamide resin becomes too wide by more than <NUM>, there is a limit that it is difficult to improve the above-described mechanical properties to a sufficient level.

The haze of the polyamide resin measured according to ASTM D1003 may be <NUM>% or less, or <NUM>% or less, <NUM>% or less, or <NUM>% or less, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%. When the haze of the polyamide resin measured according to ASTM D1003 is increased to more than <NUM>%, the opacity is increased and thus it is difficult to secure a sufficient level of transparency.

Preferably, the polyamide resin satisfies the weight average molecular weight of <NUM>/mol or more, <NUM>/mol or more, or <NUM>/mol or more, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, or <NUM>/mol to <NUM>/mol, and simultaneously it may have the haze measured according to ASTM D1003 of <NUM>% or less, or <NUM>% or less, <NUM>% or less, or <NUM>% or less, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%.

The relative viscosity of the polyamide resin (measured according to ASTM D <NUM>) may be <NUM> mPa. s (cps) or more, or <NUM> mPa. s (cps= or more, or <NUM> mPa. s (cps) to <NUM> mPa. s (cps), or <NUM> mPa. s (cps) to <NUM> mPa. s (cps), or <NUM> mPa. s (cps) to <NUM> mPa. s (cps), or <NUM> mPa. s (cps) to <NUM> mPa. s (cps), or <NUM> mPa. s (cps) to <NUM> mPa. s (cps), or <NUM> mPa. s (cps) to <NUM> mPa. When the relative viscosity of the polyamide resin (measured according to ASTM D <NUM>) is reduced to less than <NUM> mPa. s (cps), there is a limit that in the film molding process using the polyamide resin, the molding processability is lowered and the efficiency of the molding process is lowered.

As an example of a method for preparing the polyamide resin of one embodiment, a method for preparing a polyamide resin including a step of melt-kneading a compound represented by the following Chemical Formula <NUM> and a compound represented by the following Chemical Formula <NUM>, and solidifying the melt-kneaded product to form a complex; and a step of reacting the complex with an aromatic diamine monomer can be used. <CHM>
<CHM>
in Chemical Formulas <NUM> to <NUM>, X is a halogen or a hydroxyl group.

The present inventors have found through experiments that when the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> are mixed at a temperature equal to or higher than the melting point as in the method for preparing the polyamide resin, it is possible to prepare a complex of monomers mixed uniformly through the melting of the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM>, and that as this complex is reacted with an aromatic diamine monomer, an amide repeating unit derived from the compound represented by Chemical Formula <NUM>, or a block composed thereof, and an amide repeat uniting derived from the compound represented by Chemical Formula <NUM>, or a block composed thereof can be alternatively polymerized, thereby completing the present invention.

That is, the polyamide resin of one embodiment can be obtained by the preparation method of the polyamide resin.

Specifically, each of the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> exhibits different aspects in solubility and reactivity due to chemical structural differences. Therefore, even when they are added simultaneously, there is a limit in that the amide repeating unit derived from the compound represented by Chemical Formula <NUM> is predominantly formed and long blocks are formed, thereby increasing the crystallinity of the polyamide resin and making it difficult to secure transparency.

Thus, in the preparation method of the polyamide resin, the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> are not simply physically mixed, but through the formation of a complex by melt-kneading at a temperature higher than each melting point, each monomer was induced to react relatively evenly with the aromatic diamine monomer.

Meanwhile, when synthesizing existing polyamide resin, as the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> are dissolved in a solvent and then reacted with an aromatic diamine monomer in a solution state, there was a limit in that due to the deterioration by moisture or mixing in solvents, the molecular weight of the finally synthesized polyamide resin decreases. Further, due to the difference in the solubility of the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM>, the amide repeating unit derived from the compound represented by Chemical Formula <NUM> is predominantly formed and long blocks are formed, thereby increasing the crystallinity of the polyamide resin and making it difficult to secure transparency.

Thus, in the preparation method of the polyamide resin, as a complex obtained by melt-kneading the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> are reacted with the aromatic diamine monomer dissolved in the organic solvent in the form of a solid powder through cooling at a temperature lower than each melting point (minus <NUM> to plus <NUM>, or <NUM> to plus <NUM>, or plus <NUM> to plus <NUM>), the molecular weight of the finally synthesized polyamide resin was confirmed to be improved, and it was confirmed through experiments that excellent mechanical properties are secured.

Specifically, the method for preparing the polyamide resin may include melt-kneading the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM>, and solidifying the melt-kneaded product to form a complex.

In the compound represented by Chemical Formula <NUM>, X is a halogen or a hydroxyl group. Preferably, in Chemical Formula <NUM>, X is chlorine. Specific examples of the compound represented by Chemical Formula <NUM> include terephthaloyl chloride or terephthalic acid.

The compound represented by Chemical Formula <NUM> may form a repeating unit represented by Chemical Formula <NUM> by an amidation reaction of an aromatic diamine monomer. Due to the linear molecular structure, the chain packing and alignment can be kept constant in the polymer, and the surface hardness and mechanical properties of the polyamide film can be improved.

In the compound represented by Chemical Formula <NUM>, X is a halogen or a hydroxyl group. Preferably, in Chemical Formula <NUM>, X is chlorine. Specific examples of the compound represented by Chemical Formula <NUM> include phthaloyl chloride, phthalic acid, isophthaloyl chloride, or isophthalic acid.

The compound represented by Chemical Formula <NUM> may form a repeating unit represented by Chemical Formula <NUM> by an amidation reaction of an aromatic diamine monomer. Due to the curved molecular structure, it has the property of interfering with chain packing and alignment within the polymer, and it is possible to increase the amorphous region in the polyamide resin and thus improve the optical properties and the folding endurance of the polyamide film. In addition, as this is included in the polyamide resin together with the repeating unit represented by Chemical Formula <NUM>, it is possible to increase the molecular weight of the polyamide resin.

Meanwhile, in the step of melt-kneading a compound represented by Chemical Formula <NUM> and a compound represented by Chemical Formula <NUM>, and solidifying the melt-kneaded product to form a complex, the melt-kneading means mixing the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> at a temperature equal to or higher than the melting point.

In this manner, the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> are not simply physically mixed, but through the formation of a complex by melt-kneading at a temperature higher than each melting point, each monomer was induced to react relatively evenly with the aromatic diamine monomer.

Due to the difference in the solubility of the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM>, the amide repeating unit derived from the compound represented by Chemical Formula <NUM> is predominantly formed and long blocks are formed, thereby increasing the crystallinity of the polyamide resin and making it difficult to secure transparency. Therefore, in order to solve these limitations, the first polyamide segment and the second polyamide segment can alternately form a main chain including alternating-repeating units represented by Chemical Formula <NUM> as in one embodiment.

At this time, with respect to <NUM> parts by weight of the compound represented by Chemical Formula <NUM>, the compound represented by Chemical Formula <NUM> may be mixed at <NUM> parts by weight to <NUM> parts by weight, or <NUM> parts by weight to <NUM> parts by weight, or <NUM> parts by weight to <NUM> parts by weight, or <NUM> parts by weight to <NUM> parts by weight, or <NUM> parts by weight to <NUM> parts by weight. Thereby, the technical effect of increasing transmittance and clarity can be realized. When the compound represented by Chemical Formula <NUM> is mixed in an excessively small amount of less than <NUM> parts by weight with respect to <NUM> parts by weight of the compound represented by Chemical Formula <NUM>, the technical problems such as becoming opaque and the increase of haze may occur. When the compound represented by Chemical Formula <NUM> is mixed in an excessively high amount of more than <NUM> parts by weight with respect to <NUM> parts by weight of the compound represented by Chemical Formula <NUM>, the technical problems such as the reduction of physical properties (hardness, tensile strength, etc.) may occur.

In addition, in forming the complex by solidifying the molt-kneaded product, the solidifying means a physical change in which the molt-kneaded product in the molten state is cooled to a temperature equal to or less than the melting point and solidified. Thereby, the formed complex may be in a solid state. More preferably, the complex may be a solid powder obtained through an additional grinding process or the like.

Meanwhile, the step of melt-kneading a compound represented by Chemical Formula <NUM> and a compound represented by Chemical Formula <NUM>, and solidifying the melt-kneaded product to form a complex may include a step of mixing the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> at a temperature of <NUM> or higher; and a step of cooling the result of the mixing step.

The terephthaloyl chloride has a melting point of <NUM> to <NUM>, the isophthaloyl chloride has a melting point of <NUM> to <NUM>, and the phthaloyl chloride may have a melting point of <NUM> to <NUM>. Thereby, when these are mixed at a temperature of <NUM> or higher, or <NUM> or higher, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, or <NUM> to <NUM>, melt-kneading may be performed under the condition of temperature higher than the melting point of both the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM>.

In the step of cooling the result of the mixing step, the result of the melt-kneading step is left at plus <NUM> or below, or minus <NUM> to plus <NUM>, or minus <NUM> to plus <NUM>, which is a temperature condition lower than the melting point of both the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM>, so that a more uniform solid powder can be obtained through cooling.

Meanwhile, after the step of cooling the result of the mixing step, the method may further include a step of grinding the result of the cooling step. Through the grinding step, a solid complex can be prepared in powder form, and the powder obtained after the grinding step may have an average particle size of <NUM> to <NUM>.

Grinders used for grinding with such particle sizes specifically include a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill, a jog mill or sieve, a jaw crusher, and the like, but are not limited to the examples described above.

In this manner, as the melt mixture of the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> is reacted with the aromatic diamine monomer in the form of solids, specifically solid powders, through the cooling at a temperature lower than the melting point, the deterioration the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> due to moisture or their mixing in solvents is minimized, the molecular weight of the finally synthesized polyamide resin is increased, and thereby excellent mechanical properties of the polyamide resin can be ensured.

In addition, after the step of melt-kneading a compound represented by the following Chemical Formula <NUM> and a compound represented by the following Chemical Formula <NUM>, and solidifying the melt-kneaded product to form a complex, the method for preparing the polyamide resin may include a step of reacting the complex with an aromatic diamine monomer.

The reaction in the step of reacting the complex with an aromatic diamine monomer may be performed under an inert gas atmosphere at a temperature condition of minus <NUM> to <NUM> or a temperature condition of minus <NUM> to <NUM>.

Specific examples of the aromatic diamine monomer include at least one selected from the group consisting of <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobenzidine, <NUM>,<NUM>'-diaminodiphenyl sulfone, <NUM>,<NUM>'-(<NUM>-fluorenylidene)dianiline, bis(<NUM>-(<NUM>-aminophenoxy)phenyl)sulfone, <NUM>,<NUM>',<NUM>,<NUM>'-tetrachlorobenzidine, <NUM>,<NUM>-diaminofluorene, <NUM>,<NUM>-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, <NUM>,<NUM>'-oxydianiline, <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobiphenyl, <NUM>,<NUM>-bis[<NUM>-(<NUM>-aminophenoxy)phenyl]propane, <NUM>,<NUM>-bis(<NUM>-aminophenoxy)benzene, m-xylylenediamine, p-xylylenediamine and <NUM>,<NUM>'-diaminobenzanilide.

More preferably, as the aromatic diamine monomer, <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine (TFDB), <NUM>,<NUM>'-dimethyl-<NUM>,<NUM>'-diaminobenzidine, m-xylylenediamine, or p-xylylenediamine can be used.

More specifically, the step of reacting the complex with an aromatic diamine monomer may include a step of dissolving the aromatic diamine monomer in an organic solvent to prepare a diamine solution; and a step of adding a complex powder to the diamine solution.

In the step of dissolving the aromatic diamine monomer in an organic solvent to prepare a diamine solution, the aromatic diamine monomer included in the diamine solution may be present in a state dissolved in an organic solvent. Examples of the solvent are not particularly limited, but for example, common general-purpose organic solvents such as N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropionamide, <NUM>-methoxy-N,N-dimethylpropionamide, dimethyl sulfoxide, acetone, N-methyl-<NUM>-pyrrolidone, N-ethyl-<NUM>-pyrrolidone, tetrahydrofuran, chloroform, gamma-butyrolactone, ethyl lactate, methyl <NUM>-methoxypropionate, methyl isobutyl ketone, toluene, xylene, methanol, ethanol, or the like can be used without limitation.

In the step of adding a complex powder to the diamine solution, the complex powder will react with the aromatic diamine monomer dissolved in the diamine solution. As a result, the deterioration the compound represented by Chemical Formula <NUM> and the compound represented by Chemical Formula <NUM> due to moisture, or their mixing in solvents is minimized, the molecular weight of the finally synthesized polyamide resin is increased, and thereby excellent mechanical properties of the polyamide resin can be ensured.

After the step of cooling the result of the mixing step, the complex powder can prepare a complex of solids in the form of powder through the step of grinding the result of the cooling step. The powder obtained after the grinding step may have an average particle size of <NUM> to <NUM>.

According to the other embodiment of the invention, there may be provided a polymer film comprising the polyamide resin of one embodiment.

The details concerning the polyamide resin can include all of those described in the one embodiment.

More specifically, the polymer film may include a polyamide resin of one embodiment or a cured product thereof. The cured product means a material obtained through a curing process of the polyamide resin of the one embodiment.

When the polymer film is prepared using the polyamide resin of the one embodiment, excellent optical and mechanical properties can be realized, and simultaneously flexibility can be provided, so that it can be used as a material for various molded articles. For example, the polymer film may be applied to a display substrate, a display protective film, a touch panel, a window cover of a foldable device, and the like.

The thickness of the polymer film is not particularly limited, but for example, it can be freely adjusted within the range of <NUM> to <NUM>. When the thickness of the polymer film increases or decreases by a specific value, the physical properties measured in the polymer film may also change by a certain value.

The polymer film may be prepared by a conventional method such as a dry method or a wet method using the polyamide resin of the one embodiment. For example, the polymer film may be formed by a method of coating a solution containing the polyamide resin of one embodiment on an arbitrary support to form a film, evaporating the solvent from the membrane and drying it. If necessary, stretching and heat treatment of the polymer film may be further performed.

As the polymer film is produced using the polyamide resin of the one embodiment, it may exhibit excellent mechanical properties while being colorless and transparent.

Specifically, the polymer film has a haze value measured for a specimen having a thickness of <NUM> ± <NUM> according to ASTM D1003 of <NUM>% or less, or <NUM>% or less, <NUM>% or less, or <NUM>% or less, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%, or <NUM>% to <NUM>%. When the haze the polymer film measured according to ASTM D1003 is increased to more than <NUM>%, the opacity is increased and thus it is difficult to secure a sufficient level of transparency.

The polymer film has a yellowness index (YI) measured for a specimen having a thickness of <NUM>±<NUM> according to ASTM E313 of <NUM> or less, or <NUM> or less, or <NUM> to <NUM>, or <NUM> to <NUM>. When the yellowness index (YI) of the polymer film measured according to ASTM E313 is increased to more than <NUM>, the opacity is increased and thus it is difficult to secure a sufficient level of transparency.

Further, the polymer film may have a transmittance (T, @<NUM>) for visible light at wavelength of <NUM> for a specimen having a thickness of <NUM> ± <NUM> of <NUM>% or more, or <NUM>% to <NUM>%. The transmittance (T, @<NUM>) for UV light at wavelength of <NUM> may be <NUM>% or more, or <NUM>% or more.

Further, the polymer film may have a folding endurance measured for a specimen having a thickness of <NUM> ± <NUM> (the number of reciprocating bending cycles at an angle of <NUM>°, a rate of <NUM> rpm, a radius of curvature of <NUM> and a load of <NUM>) of <NUM> cycles or more, or <NUM> cycles or more, or <NUM> cycles or more, or <NUM> cycles to <NUM> Cycles, or <NUM> cycles to <NUM> cycles, or <NUM> cycles to <NUM> cycles.

Further, the polymer film may have a pencil hardness value measured for a specimen having a thickness of <NUM> ± <NUM> according to ASTM D3363 of <NUM> or more, or <NUM> or more, or <NUM> to <NUM>, or <NUM> to <NUM>.

According to another aspect of the present invention, there can be provided a resin laminate including a substrate including a polyamide resin in which an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus is <NUM> or less; and a hard coating layer formed on at least one side of the substrate, 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 <NUM> KeV to <NUM> KeV in the small-angle X-ray scattering apparatus to a solid sphere model as described in the specification, and.

The substrate may include the polyamide resin of one embodiment, and it may also include a polymer film of the other embodiment. The details concerning the polyamide resin may include all of those described in the one embodiment, and the details concerning the polymer film may include all of those described in the other embodiment.

A hard coating layer may be formed on at least one side of the substrate. A hard coating layer may be formed on one side or both sides of the substrate. When the hard coating layer is formed only on one side of the substrate, a polymer film including one or more polymers selected from the group consisting of polyimide-based, polycarbonate-based, polyester-based, polyalkyl(meth)acrylate-based, polyolefin-based and polycyclic olefin-based polymers may formed on the opposite side of the substrate.

The hard coating layer may have a thickness of <NUM> to <NUM>.

The hard coating layer can be used without particular limitation as long as it is a material known in the field of hard coating. For example, the hard coating layer may include a binder resin of photocurable resin; and inorganic particles or organic particles dispersed in the binder resin.

The photocurable resin contained in the hard coating layer is a polymer of a photocurable compound which can cause a polymerization reaction when irradiated with light such as ultraviolet rays, and may be one conventionally used in the art. However, preferably, the photocurable compound may be a polyfunctional (meth)acrylate monomer or oligomer. At this time, it is advantageous in terms of ensuring the physical properties of the hard coating layer that the number of (meth)acrylate-based functional groups is <NUM> to <NUM>, <NUM> to <NUM>, or <NUM> to <NUM>. Alternatively, the photocurable compound may be at least one selected from the group consisting of pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol hepta(meth)acrylate, tripentaerythritol hepta(meth)acrylate, trilene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane tri(meth)acrylate, and trimethylolpropane polyethoxy tri(meth)acrylate.

The inorganic particles may be, for example, silica, metal atoms such as aluminum, titanium, or zinc, or oxides or nitrides thereof. Silica fine particles, aluminum oxide particles, titanium oxide particles, zinc oxide particles, and the like can be used independently of each other.

The inorganic particles may have an average radius of <NUM> or less, or <NUM> to <NUM>. The type of the organic particles is not limited, and for example, polymer particles having an average particle size of <NUM> to <NUM> may be used.

The resin laminate can be used as a substrate or a cover window of a display device, or the like. It has high flexibility and bending durability together with high transmittance and low haze properties, so that it can be used as a substrate or cover window of a flexible display device. That is, the display device including the resin laminate, or the flexible display device including the resin laminate may be implemented.

According to the present invention, there can be provided a polyamide resin that can secure at least an adequate level of mechanical properties while improving transparency by suppressing excessive growth of the length of crystalline polymer chains, and a polymer film and resin laminate using the same.

Hereinafter, embodiments of the present invention will be described in more detail by way of examples.

<NUM> (<NUM> mol) of terephthaloyl chloride (TPC; melting point: <NUM>) and <NUM> (<NUM> mol) of isophthaloyl chloride (IPC; melting point: <NUM>) were added to a <NUM> <NUM>-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 <NUM> for <NUM> hours and then cooled at <NUM> for <NUM> hours to prepare a complex of acylchloride (specifically, terephthaloyl chloride and isophthaloyl chloride).

Subsequently, the acyl chloride complex was grinded with a jaw crusher to prepare a powder having an average particle size of <NUM>.

An acylchloride complex was prepared in the same manner as in Preparation Example <NUM>, except that <NUM> (<NUM> mol) of terephthaloyl chloride (TPC; melting point: <NUM>) and <NUM> (<NUM> mol) of isophthaloyl chloride (IPC; melting point: <NUM>) were added.

<NUM> of N,N-dimethylacetamide (DMAc) was filled into a <NUM> <NUM>-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 <NUM>, and <NUM> (<NUM> mol) of <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine (TFDB) was added and dissolved.

The mixture was stirred while adding <NUM> (<NUM> mol) of the acyl chloride complex powder obtained in Preparation Example <NUM>, and subjected to amide formation reaction at <NUM> for <NUM> hours.

After completion of the reaction, N,N-dimethylacetamide (DMAc) was added to dilute the solution to a solid content of <NUM>% or less, and the resultant was precipitated with <NUM> of methanol. The precipitated solids were filtered and then dried at <NUM> under vacuum for <NUM> hours or more to prepare a solid-state polyamide resin.

It was confirmed through <NUM>C-NMR shown in <FIG> that the polyamide resin obtained in (<NUM>) of Example <NUM>, contained <NUM> mol% of the first repeating unit obtained by an amide reaction of terephthaloyl chloride (TPC) and <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine (TFDB) and <NUM> mol% of the second repeating unit obtained by an amide reaction of isophthaloyl chloride (IPC) and <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine (TFDB).

The polyamide resin obtained in (<NUM>) of Example <NUM> was dissolved in N,N-dimethylacetamide to prepare about <NUM>% (w/v) polymer solution.

The polymer solution was applied onto a polyimide base film (UPILEX-<NUM>, UBE), and the thickness of the polymer solution was uniformly adjusted using a film applicator.

Then, after drying for <NUM> minutes at <NUM> Mathis oven, it was cured for <NUM> minutes at <NUM> while flowing nitrogen, and peeled from the base film to obtain a polymer film.

A polyamide resin was prepared in the same manner as in (<NUM>) of Example <NUM>, except that the acyl chloride complex powder obtained in Preparation Example <NUM> was used instead of the acyl chloride complex powder obtained in Preparation Example <NUM>.

It was confirmed through <NUM>C-NMR shown in <FIG> that the polyamide resin obtained in (<NUM>) of Example <NUM>, contained <NUM> mol% of the first repeating unit obtained by an amide reaction of terephthaloyl chloride (TPC) and <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine (TFDB), and <NUM> mol% of the second repeating unit obtained by an amide reaction of isophthaloyl chloride (IPC) and <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine (TFDB).

A polymer film was prepared in the same manner as in (<NUM>) of Example <NUM>, except that the polyamide resin obtained in (<NUM>) Example <NUM> was used instead of the polyamide resin obtained in (<NUM>) of Example <NUM>.

A polyamide resin was prepared in the same manner as in (<NUM>) of Example <NUM>, except that instead of the acyl chloride complex powder obtained in Preparation Example <NUM>, <NUM> (<NUM> mol) of terephthaloyl chloride (TPC) and <NUM> (<NUM> mol) of isophthaloyl chloride (IPC) were added simultaneously to perform an amide formation reaction.

A polymer film was prepared in the same manner as in (<NUM>) of Example <NUM>, except that the polyamide resin obtained in (<NUM>) of Comparative Example <NUM> was used instead of the polyamide resin obtained in (<NUM>) of Example <NUM>.

A polyamide resin was prepared in the same manner as in (<NUM>) of Example <NUM>, except that instead of the acyl chloride complex powder obtained in Preparation Example <NUM>, <NUM> (<NUM> mol) of terephthaloyl chloride (TPC) was first added, and then <NUM> (<NUM> mol) of isophthaloyl chloride (IPC) was added sequentially at about <NUM> minute intervals to perform an amide formation reaction.

A polyamide resin was prepared in the same manner as in (<NUM>) of Example <NUM>, except that instead of the acyl chloride complex powder obtained in Preparation Example <NUM>, <NUM> (<NUM> mol) of isophthaloyl chloride (IPC) was first added, and then <NUM> (<NUM> mole ) of terephthaloyl chloride (TPC) was added sequentially at about <NUM> minute intervals to perform an amide formation reaction.

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

The polymer films obtained in Examples and Comparative Examples were used to prepare a sample with a size of <NUM> in width * <NUM> in length. The sample was set on a small angle X-ray scattering apparatus (PLS-9A USAXS beam line) having a camera length of <NUM>, <NUM> at room temperature (<NUM>), and irradiated with X-rays having an energy of <NUM> KeV, <NUM> 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.

Specifically, the analysis of the average particle size, 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-<NUM>) and scattering intensity I (unit: a. ), and convoluting the plot with a Schulz-Zimm distribution.

As shown in Table <NUM>, 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 <NUM> to <NUM>, whereas the average particle size of the individual crystals contained in the polyamide resin obtained in Comparative Example <NUM> was <NUM>, the average particle size of the individual crystals contained in the polyamide resin obtained in Comparative Example <NUM> was <NUM>, and the average particle size of the individual crystals contained in the polyamide resin obtained in Comparative Example <NUM> was <NUM>, 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 <NUM>%, while the degree of crystallinity of the polyamide resin obtained in Comparative Example <NUM> was <NUM>%, which increased compared to Examples. 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 <NUM>,<NUM>'-bis(trifluoromethyl)-<NUM>,<NUM>'-biphenyldiamine (TFDB) was suppressed compared with Comparative Examples.

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 <NUM> below.

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.

Looking at Table <NUM> above, the polyamide resin of Examples prepared using the acyl chloride complex powder according to Preparation Examples <NUM> to <NUM> had a high weight average molecular weight of <NUM>/mol to <NUM>/mol, and the relative viscosity was measured to be as high as <NUM> mPa. s (cps) to <NUM> mPa. Moreover, it was confirmed that the polymer film obtained from the polyamide resin of Examples had a low yellowness index of <NUM> to <NUM> and a low haze value of <NUM>% to <NUM>% at a thickness of about <NUM>, thereby exhibiting excellent transparency. It was also confirmed that it had a high pencil hardness of <NUM> to <NUM> grade and a folding endurance that was broken at the number of reciprocating bending cycles from <NUM> to <NUM>, thereby securing excellent mechanical properties (scratch resistance and folding endurance).

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 <NUM> to <NUM> was not used in the synthesis process of the polyamide resin, the molecular weight was reduced from <NUM>,<NUM>/mol to <NUM>,<NUM>/mol compared to Examples. The viscosity was reduced from <NUM>,<NUM> mPa. s (cps) to <NUM>,<NUM> mPa. s (cps) compared to Examples.

Claim 1:
A polyamide resin in which an average particle size of individual crystals measured by a small-angle X-ray scattering apparatus is <NUM> or less, 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 <NUM> KeV to <NUM> KeV in the small-angle X-ray scattering apparatus to a solid sphere model and as further described in the specification, and
the individual crystals having the average particle size of <NUM> or less comprises a first polyamide segment including a repeating unit represented by the following Chemical Formula <NUM>, or a block comprised thereof:
<CHM>
in Chemical Formula <NUM>, Ar<NUM> is a substituted or unsubstituted arylene group having <NUM> to <NUM> carbon atoms, or a substituted or unsubstituted heteroarylene group having <NUM> to <NUM> carbon atoms, and
amorphous polymer chains present between the individual crystals having the average particle size of <NUM> or less including the first polyamide segment including the repeating unit represented by Chemical Formula <NUM> or the block composed thereof comprise a second polyamide segment including a repeating unit represented by the following Chemical formula <NUM>, or a block composed thereof:
<CHM>
in Chemical Formula <NUM>,
Ar<NUM> is a substituted or unsubstituted arylene group having <NUM> to <NUM> carbon atoms, or a substituted or unsubstituted heteroarylene group having <NUM> to <NUM> carbon atoms, and
based on the total repeating units contained in the polyamide resin, the content of the repeating units represented by Chemical Formula <NUM> is <NUM> mol% to <NUM> mol%, and the content of the repeating units represented by Chemical Formula <NUM> is <NUM> mol% to <NUM> mol%.