KR102739133B1 - Polymer film, method for manufacturing polymer film and resin laminate using the same - Google Patents

Abstract

The present invention relates to a polymer film, a method for producing a polymer film, and a resin laminate, wherein the average particle size of individual crystals measured by a small-angle X-ray scattering device is 8.0 nm or less, and the number of surface grooves formed in the polymer film is 4/0.3 ㎟ or less, each having a maximum depth of 100 nm or more.

Description

Polymer film, method for manufacturing polymer film and resin laminate using the same {POLYMER FILM, METHOD FOR MANUFACTURING POLYMER FILM AND RESIN LAMINATE USING THE SAME}

The present invention relates to a polymer film, a method for producing a polymer film, and a resin laminate in which optical properties such as transparency are improved by significantly reducing surface roughness, while mechanical properties above an appropriate level are secured.

Aromatic polyimide resins are polymers that mostly have an amorphous structure, and exhibit excellent heat resistance, chemical resistance, electrical properties, and dimensional stability due to their rigid chain structure. These polyimide resins are widely used as electrical/electronic materials.

However, polyimide resin has a limitation in securing transparency due to its dark brown color caused by the formation of CTC (charge transfer complex) of Pi electrons existing in the imide chain, and polyimide film containing it has a disadvantage in that the surface is easily scratched and scratch resistance is very weak.

In order to improve the limitations of such polyimide resins, research on polyamide resins with amide groups is being actively conducted. The amide structure induces intermolecular or intramolecular hydrogen bonds, and scratch resistance is improved through interactions such as hydrogen bonds.

However, due to the difference in solubility and reactivity (steric hindrance) and reaction rate of terephthaloyl chloride and isophthaloyl chloride used in the synthesis of polyamide resin, it is difficult for the amide repeating unit derived from terephthaloyl chloride and the amide repeating unit derived from isophthaloyl chloride to ideally and alternatively polymerize without forming blocks during polyamide polymerization.

Accordingly, there is a limitation that transparency deteriorates due to haze as the crystallinity of the polyamide resin increases due to the formation of blocks by amide repeating units derived from para acyl chloride monomers.

In addition, since the polymerization reaction proceeds while the monomer used in the synthesis of polyamide resin is dissolved in a solvent, it is difficult to secure a sufficient level of molecular weight of the final polyamide resin synthesized due to deterioration by moisture or mixing with the solvent.

Accordingly, the development of polyamide resin that can simultaneously implement transparency and mechanical properties is required.

Meanwhile, conventional polyamide films were manufactured by coating the surface of a steel belt with polyamide resin, semi-drying it, peeling it off, and removing the residual solvent through additional heat treatment. However, unlike colored polyamide films, transparent polyamide films had a problem in that they were not peeled off well in the peeling step.

A method using colored polyamide film as a substrate was attempted, but there was a limitation in that the manufacturing cost increased due to the manufacturing cost of the colored polyamide film, making it poorly economical.

Accordingly, there is a demand for the development of a method for manufacturing polyamide film that is easy to peel and does not increase manufacturing costs.

The present invention relates to a polymer film, a method for producing a polymer film, and a resin laminate in which optical properties such as transparency are improved by significantly reducing surface roughness, while mechanical properties above an appropriate level are secured.

In order to solve the above problem, the present specification provides a polymer film including a polyamide resin having an average particle size of individual crystals of 8.0 nm or less as measured by a small-angle X-ray scattering device, and having a number of surface grooves formed in the polymer film having a maximum depth of 100 nm or more of 4/0.3 ㎟ or less.

The present specification also provides a method for producing a polymer film, comprising the steps of forming a coating film by applying a composition including a polyamide resin having an average particle size of individual crystals of 8.0 nm or less as measured by a small-angle X-ray scattering device to a substrate film having a number of surface protrusions of 4/0.3㎟ or less and a maximum height of 100 nm or more.

The present specification also provides a resin laminate comprising: a substrate including the polymer film; and a hard coating layer formed on at least one surface of the substrate.

Hereinafter, a polymer film, a method for manufacturing a polymer film, and a resin laminate according to specific embodiments of the invention will be described in more detail.

Unless otherwise specified in this specification, the following terms may be defined as follows:

In this specification, when a part is said to "include" a certain component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

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

In this specification, the term "substitution" means that another functional group is bonded instead of a hydrogen atom in a compound, and the position of the substitution is not limited as long as it is a position where a hydrogen atom is substituted, that is, a position where a substituent can be substituted, and when two or more are substituted, the two or more substituents may be the same or different from each other.

The term "substituted or unsubstituted" as used herein means a group which is 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 hydroxy group; a carbonyl group; an ester group; an imide group; an amide group; a primary amino group; a carboxyl 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 a substituted or unsubstituted group in which two or more of the above-mentioned substituents are linked. For example, "a substituent having two or more substituents connected" may be a biphenyl group. That is, the biphenyl group may be an aryl group, or may be interpreted as a substituent having two phenyl groups connected. Preferably, a haloalkyl group may be used as the substituent, and an example of the haloalkyl group may be a trifluoromethyl group.

, 또는

는 다른 치환기에 연결되는 결합을 의미하고, 직접결합은 L 로 표시되는 부분에 별도의 원자가 존재하지 않은 경우를 의미한다. In this specification,

, or

means a bond that is connected to another substituent, and a direct bond means that there is no separate atom in the part indicated by L.

In the present specification, an alkyl group is a monovalent functional group derived from an alkane, which may be straight-chain or branched, and the number of carbon atoms in the straight-chain alkyl group is not particularly limited, but is preferably 1 to 20. In addition, the number of carbon atoms in the branched-chain alkyl group is 3 to 20. Specific examples of alkyl groups include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, Examples thereof include, but are not limited to, 5-methylhexyl, 2,6-dimethylheptan-4-yl, etc. The alkyl group may be substituted or unsubstituted.

In the present specification, the aryl group is a monovalent functional group derived from arene, and is preferably a group having 6 to 20 carbon atoms, but is not particularly limited thereto, and may be a monocyclic aryl group or a polycyclic aryl group. The monocyclic aryl group may be, but is not limited to, a phenyl group, a biphenyl group, a terphenyl group, etc. The polycyclic aryl group may be, but is not limited to, a naphthyl group, an anthracenyl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, a fluorenyl group, etc. The aryl group may be substituted or unsubstituted.

In the present specification, an arylene group is a divalent functional group derived from arene, and the description of the above-mentioned aryl group can be applied to them except that they are divalent functional groups. For example, they can be a phenylene group, a biphenylene group, a terphenylene group, a naphthalene group, a fluorenyl group, a pyrenyl group, a phenanthrenyl group, a perylene group, a tetracenyl group, an anthracenyl group, etc. The arylene group can be substituted or unsubstituted.

In the present specification, a heteroaryl group includes one or more non-carbon atoms or heteroatoms, and specifically, the heteroatoms may include one or more atoms selected from the group consisting of O, N, Se, and S. The number of carbon atoms is not particularly limited, but is preferably 4 to 20 carbon atoms, and the heteroaryl group may be monocyclic or polycyclic. Examples of heterocyclic groups include thiophene group, furanyl group, pyrrole group, imidazolyl group, thiazolyl group, oxazolyl group, oxadiazolyl group, pyridyl group, bipyridyl group, pyrimidyl group, triazinyl group, triazolyl group, acridyl group, pyridazinyl group, pyrazinyl group, quinolinyl group, quinazolinyl group, quinoxalinyl group, phthalazinyl group, pyrido pyrimidyl group, pyrido pyrazinyl group, pyrazino pyrazinyl group, isoquinolinyl group, indolyl group, carbazolyl group, benzoxazolyl group, benzimidazolyl group, benzothiazolyl group, benzocarbazolyl group, benzothiophene group, dibenzothiophene group, benzofuranyl group, phenanthroline group, Examples thereof include, but are not limited to, a thiazolyl group, an isoxazolyl group, an oxadiazolyl group, a thiadiazolyl group, a benzothiazolyl group, a phenothiazinyl group, an aziridyl group, an azaindoleyl group, an isoindolyl group, an indazolyl group, a purine group, a pteridine group, a beta-carbolyl group, a naphthyridine, a tert-pyridyl group, a phenazinyl group, an imidazopyridyl group, a pyropyridyl group, an azepine group, a pyrazolyl group, and a dibenzofuranyl group. The heteroaryl group may be substituted or unsubstituted.

In the present specification, the heteroarylene group has 2 to 20 carbon atoms, or 2 to 10, or 6 to 20 carbon atoms. The description of the heteroaryl group described above may be applied to the arylene group containing O, N or S as a heteroatom, except that it is a divalent functional group. The heteroarylene group may be substituted or unsubstituted.

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

Ⅰ. Polymer film

According to one embodiment of the invention, a polymer film can be provided, which includes a polyamide resin having an average particle diameter of individual crystals of 8.0 nm or less as measured by a small-angle X-ray scattering device, and in which the number of surface grooves formed in the polymer film having a maximum depth of 100 nm or more is 4/0.3 ㎟ or less.

The polymer film may include surface roughness, including surface grooves or surface protrusions.

Specifically, the surface roughness may mean a concave portion or a protrusion from an average plane having an average height of the polymer film.

More specifically, the surface groove may mean a concave portion from an average plane having an average height of the polymer film, and the surface protrusion may mean a protrusion from an average plane having an average height of the polymer film.

Additionally, the maximum depth may mean the distance from an average surface having an average height of the polymer film to the deepest point of the surface groove.

That is, the surface groove having the maximum depth of 100 nm or more may mean a surface unevenness, which is a surface groove having a maximum distance of 100 nm or more from the average surface (average height) calculated in a measurement area of a polymer film (0.3 ㎟, for example, a polymer film specimen measuring 0.6 mm in width and 0.5 mm in length).

Meanwhile, the measurement area of the surface grooves is not particularly limited, and may be, for example, one surface of a polymer film. That is, the surface grooves having the maximum depth of 100 nm or more may mean surface grooves having a distance of 100 nm or more from an average plane having an average height of one surface to the deepest point of the surface grooves, with one surface of the polymer film as the measurement area.

Specifically, one surface of the polymer film may be one of the surfaces perpendicular to the thickness direction of the polymer film. The thickness direction means a direction in which the thickness of the polymer film increases, and surface grooves may be measured targeting the outermost surface of the polymer film perpendicular to the thickness direction.

For example, assuming that the polymer film has a hexahedral shape having a length, width, and thickness, the surfaces perpendicular to the thickness direction of the polymer film can be the upper and lower surfaces facing each other across the thickness.

More specifically, one surface of the polymer film may refer to a surface of the polymer film that comes into contact with the substrate film in the method for manufacturing a polymer film described below.

In a polymer film manufactured by a method for manufacturing a polymer film, which comprises the step of forming a coating film by applying a composition containing a polyamide resin to a substrate film, described below, when the surface where the coating film comes into contact with the substrate film is used as a measurement area, the number of surface grooves having a maximum depth of 100 nm or more may be 4/0.3 ㎟ or less.

Examples of methods for measuring the above surface grooves are not particularly limited, but for example, a method may be used in which a polymer film is cut into 5 cm width and 5 cm length pieces to produce a specimen and then measured using an Optical Profiler.

More specifically, the polymer film is cut into 5 cm wide and 5 cm long pieces to prepare a specimen, and by adjusting the magnification under room temperature conditions, a NV-2700 (manufacturer: Nano System) device can be used to measure a measurement area of 0.3 ㎟, for example, a measurement area of 0.6 mm wide and 0.5 mm long, under 10x magnification conditions.

The above polyamide resin may include an amide (co)polymer containing a polyamide repeating unit. The (co)polymer includes both a polymer and a copolymer, and the polymer means a homopolymer composed of a single repeating unit, and the copolymer means a composite polymer containing two or more types of repeating units.

As described above, the inventors of the present invention have experimentally confirmed that a polyamide resin having an average particle size of individual crystals of 8.0 nm or less as measured by a small-angle X-ray scattering device has excellent mechanical properties of a crystalline polymer, but has a significantly low haze value and yellowness, etc., since the growth of individual crystals forming the crystal structure is slowed down to have a relatively small size, and can have high flexibility and bending durability, and have thus completed the invention.

In contrast, if the average particle size of individual crystals measured by a small-angle X-ray scattering device for the polyamide resin increases excessively to exceed 8.0 nm, the proportion or size of the portion having crystallinity within the polymer film may grow excessively, so that the crystal characteristics are strongly implemented, thereby reducing the flexibility or bending durability of the polymer itself and rapidly increasing the haze value, which may reduce transparency.

In addition, the inventors of the present invention experimentally confirmed that the polymer film of the above embodiment includes a polyamide resin having an average particle size of individual crystals of 8.0 nm or less as measured by a small-angle X-ray scattering device, and that the number of surface grooves formed in the polymer film having a maximum depth of 100 nm or more satisfies 4/0.3㎟ or less, thereby significantly reducing the haze value and improving optical properties such as transparency, while securing mechanical properties above an appropriate level, thereby completing the invention.

Specifically, the polymer film may have a number of surface grooves having a maximum depth of 100 nm or more formed in the polymer film of 4/0.3 ㎟ or less, 0/0.3 ㎟ or more and 4/0.3 ㎟ or less, 0/0.3 ㎟ or more and 3/0.3 ㎟ or less, 0/0.3 ㎟ or more and 2/0.3 ㎟ or less, 0/0.3 ㎟ or more and 1/0.3 ㎟ or less, or 0/0.3 ㎟.

In this way, the polymer film has almost no surface grooves, i.e., surface unevenness, with a maximum depth of 100 nm or more, and since the surface grooves are significantly reduced, it can have mechanical properties above an appropriate level and at the same time, have a significantly lower haze value, thereby achieving colorless and transparent optical properties.

In contrast, when the polymer film includes surface grooves of a maximum depth of 100 nm or more, i.e., 5/0.3㎟ or more, the surface includes excessively many unevennesses, which may increase the haze value and significantly deteriorate the optical properties.

The number of surface grooves of the above polymer film can be confirmed using a commonly known measuring method and measuring device. For example, a method can be used in which a polymer film is cut into 5 cm width and 5 cm length to prepare a specimen and then measured using an Optical Profiler.

More specifically, the polymer film is cut into 5 cm in width and 5 cm in length to manufacture a specimen, and the magnification is adjusted under room temperature conditions, and the number of surface grooves having a maximum depth of 100 nm or more, measured for a measurement area of 0.3 ㎟, for example, a measurement area of 0.6 mm in width and 0.5 mm in length, is 4/0.3 ㎟ or less, 0/0.3 ㎟ or more and 4/0.3 ㎟ or less, 0/0.3 ㎟ or more and 3/0.3 ㎟ or less, 0/0.3 ㎟ or more and 2/0.3 ㎟ or less, 0/0.3 ㎟ or more and 1/0.3 ㎟ or less, or 0/0.3 ㎟. there is.

Meanwhile, the polymer film of the above embodiment may have an arithmetic mean roughness (Ra) of 10 nm or less, 1 nm or more and 7 nm or less, or 3 nm or more and 5 nm or less.

The above arithmetic mean roughness (Ra) can be as specified in JIS B0601-1994, and statistically means the arithmetic mean of the deviation of the roughness curve from the mean line. That is, the arithmetic mean roughness can be calculated by the following mathematical expression 1 when the reference length L and the deviation f(x) of the roughness curve from the mean line are:

[Mathematical Formula 1]

The above reference length refers to the length in the measurement direction of the reference line used to obtain the characteristics of surface roughness, and the above average line refers to a straight line that minimizes the sum of the squares of the deviations to the roughness curve. In this specification, the arithmetic average roughness is created based on the values measured by the Optical Profiler.

Since the arithmetic mean roughness of the above polymer film is 10 nm or less, surface grooves or unevenness are significantly reduced, and thus mechanical properties above an appropriate level can be implemented while the haze value is significantly reduced, thereby allowing colorless, transparent optical properties to be achieved.

In contrast, if the arithmetic mean roughness of the polymer film exceeds 10 nm, the film may contain excessive surface grooves or surface unevenness, which may increase the haze value and significantly deteriorate the optical properties.

Meanwhile, the polymer film may include a polyamide resin having an average particle size of individual crystals of 8.0 nm or less as measured by a small-angle X-ray scattering device. The polyamide resin may include a plurality of individual crystals. The average particle size of the individual crystals contained in the polyamide resin may be obtained by checking the particle sizes of all crystals contained in the polymer film and dividing the sum of these particle sizes by the number of individual crystals through a number-average particle size calculation method.

The average particle diameter of the above individual decisions can be measured using an analysis device by fitting the scattering pattern obtained by irradiating X-rays having energies of 10 KeV to 20 KeV, or 10 KeV to 14 KeV, or 16 KeV to 20 KeV in a small-angle X-ray scattering device to a solid sphere model.

The X-rays to be investigated above can be irradiated using, for example, a method of irradiating X-rays having an energy of 10 KeV to 14 KeV and X-rays having an energy of 16 KeV to 20 KeV together.

The scattering pattern, which is data obtained from the above-described small-angle X-ray scattering device, can be a result measured by irradiating X-rays having an energy of 10 KeV to 20 KeV using the small-angle X-ray scattering device at a temperature of 20° C to 30° C. As a detector within the above-described small-angle X-ray scattering device, an imaging plate, a position-sensitive detector (PSPC), or the like can be used.

Thereafter, the average particle size of the individual crystals can be analyzed using analysis equipment separately installed inside or outside the small-angle X-ray scattering device. An example of the small-angle X-ray scattering device is the PLS 9A beamline, and an example of the analysis equipment is the computer program NIST SANS package.

Specifically, the average particle diameter of the individual crystals can be obtained by fitting the shape of the individual crystals contained in the sample to a solid sphere model, and convolving the plot of the wavenumber q (unit: Å ^-1 ) and the scattering intensity I (unit: au) with the Schulz-Zimm distribution, through calculation using a computer program (NIST SANS package).

The above decision may be a group of individual crystals having a particle size of 0.1 nm to 15 nm, and the individual crystals included in the group may have an average particle size of 0.8 nm or less. More specifically, 95%, or 99% of the individual crystals included in the group may have a particle size of 0.8 nm or less. That is, since a majority of the individual crystals have a particle size of 0.8 nm or less, or 7 nm or less, or 0.1 nm to 8.0 nm, or 0.1 nm to 7 nm, or 1 nm to 8 nm, or 1 nm to 7 nm, or 3 nm to 8 nm, or 3 nm to 7 nm, or 5 nm to 6.8 nm, the average particle size of the individual crystals may also satisfy the above-described range.

More specifically, the average particle size of individual crystals measured by the small-angle X-ray scattering device can be 8.0 nm or less, or 7 nm or less, or from 0.1 nm to 8.0 nm, or from 0.1 nm to 7 nm, or from 1 nm to 8 nm, or from 1 nm to 7 nm, or from 3 nm to 8 nm, or from 3 nm to 7 nm, or from 5 nm to 6.8 nm.

Specifically, when X-rays are irradiated to a polyamide resin sample using the above-described small-angle X-ray scattering device, a small-angle X-ray scattering pattern is acquired through a detector, and when this is analyzed using analysis equipment, the average semi-grain diameter (R _c ) value of individual crystals contained in the polyamide resin sample can be obtained. Through this, the average grain diameter of the individual crystals can be finally obtained by calculating twice the average semi-grain diameter (R _c ) of the individual crystals described above.

More specifically, referring to the crystal structure of the polymer film of the above-described embodiment as described in the following Drawing 1, the polymer film is composed of a plurality of individual crystals (1) and amorphous polymer chains (3) existing between the individual crystals, and a particle size (2) can be defined for the individual crystals.

Meanwhile, the individual crystals (1) can be formed by polyamide resin chains gathering into a bundle, as shown in the schematic diagram below. In particular, the length of the individual crystals can grow through overlapping between crystalline polymer blocks contained in the polyamide resin, and although it is difficult to specifically specify the shape of the overlapping individual crystals, it can be roughly considered to have a spherical structure due to three-dimensional growth, a lamellar structure due to two-dimensional growth, or a structure having an intermediate form between three dimensions and two dimensions.

Preferably, the polyamide resin may have a dimension of individual crystals of 3.0 or more, or 3.0 to 4.0, as measured by a small-angle X-ray scattering device. The dimension of individual crystals of the polyamide resin can be measured by an analysis device by fitting a scattering pattern obtained by irradiating X-rays having an energy of 10 KeV to 20 KeV, or 10 KeV to 14 KeV, or 16 KeV to 20 KeV, with a solid sphere model. The small-angle X-ray scattering device and the analysis contents thereof include the contents described above in the average particle diameter of the individual crystals.

Meanwhile, the polyamide resin may further include amorphous polymer chains existing between individual crystals having an average particle diameter of 8.0 nm or less. More specifically, referring to the crystal structure of the polymer film of the above-described embodiment described in Drawing 1 below, the polymer film may be composed of a plurality of individual crystals (1) and amorphous polymer chains (3) existing between the individual crystals.

By the amorphous polymer chains described above, the average particle size growth of the individual crystals described above is suppressed, so that the polymer film can satisfy an average particle size of the individual crystals measured by a small-angle X-ray scattering device of 8.0 nm or less.

At this time, the distance between individual crystals having an average particle diameter of 8.0 nm or less may be 0.1 nm to 100 nm, or 1 nm to 100 nm, or 30 nm to 100 nm. The distance between individual crystals having an average particle diameter of 8.0 nm or less can also be measured by a small-angle X-ray scattering device.

In the above polyamide resin, specific examples of individual crystal components having an average particle size of 8.0 nm or less as measured by a small-angle X-ray scattering device are not particularly limited, and various aromatic amide repeating units used in the production of crystalline polyamide resin can be applied without limitation.

An example of a component of individual crystals having an average particle size of 8.0 nm or less as measured by the above-described small-angle X-ray scattering device may include a first aromatic amide repeating unit derived from a combination of a 1,4-aromatic diacyl compound and an aromatic diamine compound. Polymer chains formed of the first aromatic amide repeating unit may be bundled to form individual crystals having an average particle size of 8.0 nm or less.

Specific examples of the above 1,4-aromatic diacyl compounds include terephthaloyl chloride, or terephthalic acid. In addition, examples of the aromatic diamine monomer include 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 2,2'-dimethyl-4,4'-diaminobenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-(9-fluorenylidene)dianiline, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2',5,5'-tetrachlorobenzidine, 2,7-diaminofluorene, 4,4-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene, m-xylylenediamine, p-xylylenediamine, and One or more selected from the group consisting of 4,4'-diaminobenzanilide may be mentioned.

Preferably, the 1,4-aromatic diacyl compound comprises terephthaloyl chloride or terephthalic acid, and the aromatic diamine compound may comprise 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine.

More specifically, the individual crystals having an average particle diameter of 8.0 nm or less may include a first polyamide segment including a repeating unit represented by the following chemical formula 1, or a block composed thereof.

[Chemical formula 1]

In the above chemical formula 1, Ar 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.

In the above chemical formula 1, Ar ₁ is an arylene group having 6 to 20 carbon atoms 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 2,2'-bis(trifluoromethyl)-4,4'-biphenylene group.

More specifically, in the chemical formula 1, Ar ₁ may be a divalent organic functional group derived from an aromatic diamine monomer, and specific examples of the aromatic diamine monomer include 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 2,2'-dimethyl-4,4'-diaminobenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-(9-fluorenylidene)dianiline, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2',5,5'-tetrachlorobenzidine, 2,7-diaminofluorene, 4,4-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene, and At least one selected from the group consisting of 4,4'-diaminobenzanilide may be mentioned. More preferably, the aromatic diamine monomer may be 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (TFDB) or 2,2'-dimethyl-4,4'-diaminobenzidine.

The above first polyamide segment may include a repeating unit represented by the above chemical formula 1, or a block composed of a repeating unit represented by the above chemical formula 1.

A specific example of the repeating unit represented by the above chemical formula 1 may include the repeating unit represented by the following chemical formula 1-1.

[Chemical Formula 1-1]

The repeating unit represented by the above chemical formula 1 is an amide repeating unit derived from a combination of a 1,4-aromatic diacyl compound and an aromatic diamine compound, specifically, an amide repeating unit formed by an amidation reaction of terephthaloyl chloride or terephthalic acid and an aromatic diamine monomer, and due to its linear molecular structure, chain packing and alignment can be maintained consistently within the polymer, and the surface hardness and mechanical properties of the polyamide film can be improved.

Specific examples of the above 1,4-aromatic diacyl compounds include terephthaloyl chloride, or terephthalic acid. In addition, examples of the aromatic diamine monomer include 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 2,2'-dimethyl-4,4'-diaminobenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-(9-fluorenylidene)dianiline, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2',5,5'-tetrachlorobenzidine, 2,7-diaminofluorene, 4,4-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene, m-xylylenediamine, p-xylylenediamine, and One or more selected from the group consisting of 4,4'-diaminobenzanilide may be mentioned.

Preferably, the 1,4-aromatic diacyl compound comprises terephthaloyl chloride or terephthalic acid, and the aromatic diamine compound may comprise 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine.

The number average molecular weight of the first polyamide segment may be 100 g/mol to 5000 g/mol, or 100 g/mol to 3000 g/mol, or 100 g/mol to 2500 g/mol, or 100 g/mol to 2450 g/mol. If the number average molecular weight of the first polyamide segment increases to exceed 5000 g/mol, the crystallinity of the polyamide resin may increase as the chain of the first polyamide segment becomes excessively long, and thus the polymer film may have a high haze value, making it difficult to secure transparency. The number average molecular weight of the first polyamide segment is not limited to examples of a method for measuring it, but can be confirmed, for example, through SAXS (Small-angle X-ray scattering) analysis.

The above first polyamide segment can be represented by the following chemical formula 5.

[Chemical Formula 5]

In the chemical formula 5, Ar 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, and a is an integer of 1 to 5. In the chemical formula 5, when a is 1, the chemical formula 5 may be a repeating unit represented by the chemical formula 1. In the chemical formula 5, when a is 2 to 5, the chemical formula 5 may be a block composed of a repeating unit represented by the chemical formula 1. In the chemical formula 5, the description of Ar ₁ includes the contents described above in the chemical formula 1.

Based on all repeating units contained in the polymer film, the proportion of the repeating unit represented by the chemical formula 1 may be 40 mol% to 95 mol%, 50 mol% to 95 mol%, or 60 mol% to 95 mol%, or 70 mol% to 95 mol%, or 50 mol% to 90 mol%, or 50 mol% to 85 mol%, or 60 mol% to 85 mol%, or 70 mol% to 85 mol%, or 80 mol% to 85 mol%, or 82 mol% to 85 mol%.

In this way, a polymer film containing the repeating unit represented by the chemical formula 1 in the above-described amount can secure a sufficient level of molecular weight and thereby secure excellent mechanical properties.

In addition, in the polymer film, specific examples of amorphous polymer chains existing between individual crystals having an average particle diameter of 8.0 nm or less are not particularly limited, and various aromatic amide repeating units used in the production of amorphous polyamide resins can be applied without limitation.

An example of an amorphous polymer chain component existing between individual crystals having an average particle size of 8.0 nm or less as measured by the above small-angle X-ray scattering device may include a second aromatic amide repeating unit derived from a combination of a 1,2-aromatic diacyl compound and an aromatic diamine compound, or a third aromatic amide repeating unit derived from a combination of a 1,3-aromatic diacyl compound and an aromatic diamine compound, or a mixture thereof. The polymer chains composed of the above-described second aromatic amide repeating unit or the third aromatic amide repeating unit can implement amorphous characteristics.

Specific examples of the above 1,2-aromatic diacyl compound include phthaloyl chloride or phthalic acid. In addition, specific examples of the above 1,3-aromatic diacyl compound include isophthaloyl chloride or isophthalic acid. Examples of the above aromatic diamine monomers include 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 2,2'-dimethyl-4,4'-diaminobenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-(9-fluorenylidene)dianiline, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2',5,5'-tetrachlorobenzidine, 2,7-diaminofluorene, 4,4-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene, m-xylylenediamine, p-xylylenediamine, and One or more selected from the group consisting of 4,4'-diaminobenzanilide may be mentioned.

Preferably, the 1,2-aromatic diacyl compound may include phthaloyl chloride or phthalic acid, the 1,3-aromatic diacyl compound may include isophthaloyl chloride or isophthalic acid, and the aromatic diamine compound may include 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine.

More specifically, an amorphous polymer chain present between individual crystals having an average particle diameter of 8.0 nm or less, including a first polyamide segment comprising a repeating unit represented by the above chemical formula 1, or a block composed thereof, may include a second polyamide segment comprising a repeating unit represented by the following chemical formula 2, or a block composed thereof.

[Chemical formula 2]

In the above chemical formula 2, Ar 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.

In the above chemical formula 2, Ar ₂ is an arylene group having 6 to 20 carbon atoms 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 2,2'-bis(trifluoromethyl)-4,4'-biphenylene group.

More specifically, in the chemical formula 2, Ar ₂ may be a divalent organic functional group derived from an aromatic diamine monomer, and specific examples of the aromatic diamine monomer include 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 2,2'-dimethyl-4,4'-diaminobenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-(9-fluorenylidene)dianiline, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2',5,5'-tetrachlorobenzidine, 2,7-diaminofluorene, 4,4-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene, and At least one selected from the group consisting of 4,4'-diaminobenzanilide may be mentioned. More preferably, the aromatic diamine monomer may be 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (TFDB) or 2,2'-dimethyl-4,4'-diaminobenzidine.

The second polyamide segment may include a repeating unit represented by the chemical formula 2, or a block composed of a repeating unit represented by the chemical formula 2.

More specifically, the repeating unit represented by the chemical formula 2 may include one type of repeating unit among the repeating unit represented by the chemical formula 2-1 below; or the repeating unit represented by the chemical formula 2-2 below.

[Chemical Formula 2-1]

[Chemical Formula 2-2]

In the above chemical formulas 2-1 to 2-2, Ar 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. A detailed description of Ar ₂ includes the contents described above in the above chemical formula 2.

The repeating unit represented by the above chemical formula 2-1 is a repeating unit formed by the amidation reaction of isophthaloyl chloride or isophthalic acid and an aromatic diamine monomer, and the repeating unit represented by the above chemical formula 2-2 is a repeating unit formed by the amidation reaction of phthaloyl chloride or phthalic acid and an aromatic diamine monomer.

A specific example of the repeating unit represented by the above chemical formula 2-1 may include the repeating unit represented by the following chemical formula 2-4.

[Chemical Formula 2-4]

A specific example of the repeating unit represented by the above chemical formula 2-2 may include the repeating unit represented by the following chemical formula 2-5.

[Chemical Formula 2-5]

Meanwhile, the second polyamide segment can be represented by the following chemical formula 6.

[Chemical formula 6]

In the chemical formula 6, Ar 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, and b is an integer of 1 to 3, or 1 to 2. In the chemical formula 6, when b is 1, the chemical formula 6 may be a repeating unit represented by the chemical formula 2. In the chemical formula 6, when b is 2 to 3, the chemical formula 6 may be a block composed of a repeating unit represented by the chemical formula 2.

The repeating unit represented by the above chemical formula 2 is a repeating unit formed by the amidation reaction of isophthaloyl chloride, isophthalic acid or phthaloyl chloride, phthalic acid and an aromatic diamine monomer, and due to its bent molecular structure, has the property of interfering with chain packing and alignment within a polymer, and can improve the optical properties and bending strength of a polyamide film by increasing the amorphous region in the polyamide resin. In addition, by being included in the polyamide resin together with the repeating unit represented by the above chemical formula 1, the molecular weight of the polyamide resin can be increased.

Based on all repeating units contained in the polyamide resin, the proportion of the repeating unit represented by the chemical formula 2 may be 5 mol% to 60 mol%, 5 mol% to 50 mol%, or 5 mol% to 40 mol%, or 5 mol% to 30 mol%, or 10 mol% to 50 mol%, or 15 mol% to 50 mol%, or 15 mol% to 40 mol%, or 15 mol% to 30 mol%, or 15 mol% to 20 mol%, or 15 mol% to 18 mol%.

In this way, the polyamide resin containing the repeating unit represented by the chemical formula 2 in the above-described content can inhibit the length growth of a chain composed of only the specific repeating unit represented by the chemical formula 1, thereby lowering the crystallinity of the resin, and thus ensuring excellent transparency by having a low haze value.

Meanwhile, the first polyamide segment and the second polyamide segment can form a main chain including a cross-repeating unit represented by the following chemical formula 3. That is, the first polyamide segment included in individual crystals having an average particle diameter of 8.0 nm or less as measured by the small-angle X-ray scattering device can form a cross-repeating unit represented by the following chemical formula 3 with the second polyamide segment included in an amorphous polymer chain existing between the individual crystals.

Accordingly, the polyamide resin of the above embodiment has a structure in which a number of individual crystals and amorphous polymer chains are repeated, as shown in the crystal structure shown in Fig. 1 below, and can suppress the continuous size growth of only the individual crystals. Through this, the average particle diameter of the individual crystals measured by a small-angle X-ray scattering device can be reduced to 8.0 nm or less.

[Chemical formula 3]

In the above chemical formula 3, A is the first polyamide segment, and B is the second polyamide segment.

Specifically, the main chain of the polyamide resin included in the polymer film may be, as in the chemical formula 3, a polymer chain in which 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, or phthalic acid alternately form a polymer chain. That is, the second polyamide segment is positioned between the first polyamide segments and may play a role in suppressing the length growth of the first polyamide segment.

Since the second polyamide segment is included in an amorphous polymer chain existing between individual crystals having an average particle diameter of 8.0 nm or less, and the first polyamide segment is included in the individual crystals having an average particle diameter of 8.0 nm or less, the amorphous polymer chain in the polymer film can play a role in suppressing the size growth of the individual crystals while being positioned between individual crystals having an average particle diameter of 8.0 nm or less. This can also be confirmed through the crystal structure shown in Fig. 1 below.

In this way, when the size growth of the individual crystals is suppressed, the crystal characteristics by the individual crystals are reduced, and the haze value of the polymer film can be significantly reduced, so that excellent transparency can be implemented.

Meanwhile, the fact that the main chain of the polyamide resin included in the polymer film alternately forms a polymer chain of 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, as in the chemical formula 3, is due to the formation of a melt-blended composite in the polyamide resin manufacturing method of the present invention described below.

To explain with a more specific example, the alternating repeat unit represented by the chemical formula 3 may be a repeat unit represented by the following chemical formula 4.

[Chemical formula 4]

In the above chemical formula 4, Ar ₁ and Ar 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, or 1 to 5, and b1 and b2 are each independently an integer of 1 to 5, or 1 to 3.

In the above chemical formula 4, the crystalline polymer block (derived from terephthaloyl chloride or terephthalic acid) having a repeating unit number of a1 or a2 can form individual crystals having an average particle diameter of 8.0 nm or less as measured by the small-angle X-ray scattering apparatus. Furthermore, in the above chemical formula 4, the non-crystalline polymer block (derived from isophthaloyl chloride, isophthalic acid, or phthaloyl chloride, phthalic acid) having a repeating unit number of b1 or b2 can form an amorphous polymer chain existing between individual crystals having an average particle diameter of 8.0 nm or less as measured by the small-angle X-ray scattering apparatus.

That is, the polyamide resin included in the polymer film includes a first polyamide segment including a repeating unit represented by the chemical formula 1, or a block composed thereof; and a second polyamide segment including a repeating unit represented by the chemical formula 2, or a block composed thereof; and the first polyamide segment and the second polyamide segment can form a main chain including a cross-repeating unit represented by the chemical formula 3.

The present inventors experimentally confirmed that, as the average particle diameter of individual crystals is reduced to 8.0 nm or less, as in the polyamide resin included in the polymer film of the above-described embodiment, the length growth of a polymer block (hereinafter, “first polyamide segment”) composed of a repeating unit derived from terephthaloyl chloride or terephthalic acid inside the polyamide resin is minimized, thereby lowering the crystallinity of the polyamide resin and implementing a transparent polymer film, thereby completing the invention.

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

At this time, the first polyamide segment is included in individual crystals of the polyamide resin and exhibits crystalline characteristics, and the second polyamide segment is included in an amorphous polymer chain between the individual crystals and exhibits amorphous characteristics.

Accordingly, when the length growth of the first polyamide segment is suppressed, the average particle diameter of individual crystals measured by a small-angle X-ray scattering device is measured to be relatively small, and since the polyamide resin can significantly lower the haze value of the polymer film while the crystal characteristics of the first polyamide segment are reduced, excellent transparency can be implemented.

Conversely, if the length growth inhibition effect of the first polyamide segment by the second polyamide segment decreases and the length growth of the first polyamide segment proceeds excessively, the average particle diameter of individual crystals measured by a small-angle X-ray scattering device is measured to be relatively large, and the polyamide resin may have poor transparency while the crystal characteristics of the first polyamide segment increase and the haze value of the polymer film rapidly increases.

However, the polyamide resin can have a sufficient level of weight average molecular weight, thereby achieving a sufficient level of mechanical properties.

Meanwhile, the polyamide resin may have a crystallinity of 20% or less, or 1% to 20%, as measured by a small-angle X-ray scattering device. The crystallinity of the polyamide resin can be measured by an analysis device by fitting a scattering pattern obtained by irradiating X-rays having an energy of 10 KeV to 20 KeV, or 10 KeV to 14 KeV, or 16 KeV to 20 KeV, with a solid sphere model. The small-angle X-ray scattering device and the analysis contents thereof include the contents described above in the average particle diameter of the individual crystals.

The weight average molecular weight of the above polyamide resin may be 330,000 g/mol or more, 420,000 g/mol or more, or 500,000 g/mol or more, or 330,000 g/mol to 1,000,000 g/mol, or 420,000 g/mol to 1,000,000 g/mol, or 500,000 g/mol to 1,000,000 g/mol, or 420,000 g/mol to 800,000 g/mol, or 420,000 g/mol to 600,000 g/mol, or 450,000 g/mol to 550,000 g/mol.

The high measured weight average molecular weight of the above polymer appears to be due to the formation of a melt-blended composite in the polyamide resin manufacturing method of the present invention described below. If the weight average molecular weight of the above polymer decreases below 330,000 g/mol, there is a problem in that mechanical properties such as flexibility and pencil hardness decrease.

The molecular weight distribution of the polyamide resin may be 3.0 or less, or 2.5 or less, or 1.9 or less, or 1.5 to 1.95, or 1.5 to 1.9, or 1.6 to 1.9, or 1.8 to 1.9. Through such a narrow range of molecular weight distribution, the mechanical properties of the polymer film, such as bending characteristics and hardness characteristics, can be improved. If the molecular weight distribution of the polymer becomes excessively wide, exceeding 3.0, there is a limitation that it is difficult to improve the mechanical properties described above to a sufficient level.

The haze of the polyamide resin as measured by ASTM D1003 may be 3.0% or less, or 1.5% or less, or 1.00% or less, or 0.85% or less, or 0.10% to 3.0%, or 0.10% to 1.5%, or 0.10% to 1.00%, or 0.50% to 1.00%, or 0.80% to 1.00%, or 0.81% to 0.97%. When the haze of the polymer film as measured by ASTM D1003 exceeds 3.0%, the opacity increases and it is difficult to secure a sufficient level of transparency.

Preferably, the polyamide resin satisfies a weight average molecular weight of 330,000 g/mol or more, 420,000 g/mol or more, or 500,000 g/mol or more, or 330,000 g/mol to 1,000,000 g/mol, or 420,000 g/mol to 1,000,000 g/mol, or 500,000 g/mol to 1,000,000 g/mol, or 420,000 g/mol to 800,000 g/mol, or 420,000 g/mol to 600,000 g/mol, or 450,000 g/mol to 550,000 g/mol, and at the same time, a haze measured by ASTM D1003 for the polymer film is 3.0% or less, or 1.5% or less, or 1.00% or less, or 0.85% or less, or 0.50% to 3.0%, or 0.50% to 1.5%, or 0.50% to 1.00%, or 0.50% to 0.85%, or 0.70% to 0.85%, or 0.77% to 0.85%, or 0.80% to 0.85%.

The relative viscosity (measured according to ASTM D 2196) of the polyamide resin may be 45,000 cps or more, 60,000 cps or more, or 45,000 cps to 500,000 cps, or 60,000 cps to 500,000 cps, or 70,000 cps to 400,000 cps, or 80,000 cps to 300,000 cps, or 100,000 cps to 200,000 cps, or 110,000 cps to 174,000 cps. When the relative viscosity (measured according to ASTM D 2196) of the polyamide resin decreases below 60,000 cps, there is a limitation in that the molding processability decreases in a film molding process using the polyamide resin, thereby decreasing the efficiency of the molding process.

As an example of a method for producing the above polyamide resin, a method for producing a polyamide resin may be used, including the steps of melting and mixing a compound represented by the following chemical formula 7 and a compound represented by the following chemical formula 8, solidifying the melted mixture to form a complex; and reacting the complex with an aromatic diamine monomer.

[Chemical formula 7]

[Chemical formula 8]

In the above chemical formulas 7 to 8, X is a halogen or a hydroxyl group.

The present inventors experimentally confirmed that when the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 are mixed at a temperature higher than the melting point as in the method for producing the polyamide resin, a complex of monomers uniformly mixed through melting of the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 can be produced, and when this is reacted with an aromatic diamine monomer, the amide repeating unit derived from the compound represented by the chemical formula 7, or a block composed thereof, and the amide repeating unit derived from the compound represented by the chemical formula 8, or a block composed thereof can alternately polymerize, thereby completing the invention.

That is, by the above polyamide resin manufacturing method, the polymer of the polymer film of the above embodiment can be obtained.

Specifically, since the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 each exhibit different aspects in terms of solubility and reactivity due to differences in their chemical structures, even when they are introduced simultaneously, there is a limitation in that the amide repeating unit derived from the compound represented by the chemical formula 7 is formed overwhelmingly dominantly, forming a long block, thereby increasing the crystallinity of the polyamide resin and making it difficult to secure transparency.

Accordingly, in the polyamide resin manufacturing method, the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 are not simply physically mixed, but rather a complex is formed through melt mixing at a temperature higher than the melting point of each, thereby inducing each monomer to react relatively evenly with the aromatic diamine monomer.

Meanwhile, in the synthesis of conventional polyamide resins, since the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 are dissolved in a solvent and then reacted with an aromatic diamine monomer in a solution state, there was a limitation that the molecular weight of the final polyamide resin synthesized decreased due to deterioration by moisture or mixing with the solvent, and due to the difference in solubility between the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8, the amide repeating unit derived from the compound represented by the chemical formula 7 was formed overwhelmingly dominantly, forming a long block, thereby increasing the crystallinity of the polyamide resin and making it difficult to secure transparency.

Accordingly, in the polyamide resin manufacturing method, the composite obtained by melt mixing of the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 is cooled at a temperature lower than each melting point (-10° C. to 30° C., or 0° C. to 30° C., or 10° C. to 30° C.) to a solid powder form, thereby reacting with an aromatic diamine monomer dissolved in an organic solvent, thereby confirming that the molecular weight of the final synthesized polyamide resin is improved, and it was experimentally confirmed that excellent mechanical properties are secured through this.

Specifically, the method for producing the polyamide resin may include a step of melting and mixing a compound represented by the chemical formula 7 and a compound represented by the chemical formula 8, and solidifying the melted mixture to form a composite.

In the compound represented by the above chemical formula 7, X is halogen or a hydroxyl group. Preferably, in the above chemical formula 7, X is chlorine. Specific examples of the compound represented by the above chemical formula 7 include terephthaloyl chloride or terephthalic acid.

The compound represented by the above chemical formula 7 can form a repeating unit represented by the above chemical formula 1 through an amidation reaction of an aromatic diamine monomer, and due to its linear molecular structure, the chain packing and alignment can be maintained consistently within the polymer, and the surface hardness and mechanical properties of the polyamide film can be improved.

In the compound represented by the above chemical formula 8, X is halogen or a hydroxyl group. Preferably, in the above chemical formula 8, X is chlorine. Specific examples of the compound represented by the above chemical formula 8 include phthaloyl chloride, phthalic acid, isophthaloyl chloride, or isophthalic acid.

The compound represented by the above chemical formula 8 can form a repeating unit represented by the above chemical formula 2 by an amidation reaction of an aromatic diamine monomer, and due to its bent molecular structure, has a property of interfering with chain packing and alignment within a polymer, and can improve the optical properties and bending strength of a polyamide film by increasing an amorphous region in a polyamide resin. In addition, since the repeating unit represented by the above chemical formula 2 derived from the compound represented by the above chemical formula 8 is included in the polyamide resin together with the repeating unit represented by the above chemical formula 1, the molecular weight of the polyamide resin can be increased.

Meanwhile, in the step of melting and mixing the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 and solidifying the melted and mixed material to form a complex, the melting and mixing means mixing the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 at a temperature higher than the melting point.

In this way, the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 are not simply physically mixed, but rather, through complex formation by melt mixing at a temperature higher than the melting point of each, each monomer can be induced to react relatively evenly with the aromatic diamine monomer.

Accordingly, due to the difference in solubility between the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8, the amide repeating unit derived from the compound represented by the chemical formula 7 is formed overwhelmingly predominantly to form a long block, thereby increasing the crystallinity of the polyamide resin and overcoming the limitation of making it difficult to secure transparency, and, as in the above-described exemplary embodiment, the first polyamide segment and the second polyamide segment can form a main chain including the crossed repeating unit represented by the chemical formula 3 alternately.

At this time, with respect to 100 parts by weight of the compound represented by the chemical formula 7, the compound represented by the chemical formula 8 may be mixed in an amount of 5 parts by weight to 60 parts by weight, or 5 parts by weight to 50 parts by weight, or 5 parts by weight to 25 parts by weight, or 10 parts by weight to 30 parts by weight, or 15 parts by weight to 25 parts by weight. Through this, the technical effect of increasing transmittance and clarity can be realized. With respect to 100 parts by weight of the compound represented by the chemical formula 7, if the compound represented by the chemical formula 8 is mixed in an excessively small amount of less than 5 parts by weight, the material becomes opaque and there may occur a technical problem of increased Hazeness, and with respect to 100 parts by weight of the compound represented by the chemical formula 7, if the compound represented by the chemical formula 8 is mixed in an excessive amount of more than 60 parts by weight, there may occur a technical problem of decreased physical properties (hardness, tensile strength, etc.).

In addition, when forming a composite by solidifying the molten mixture, the solidification means a physical change in which the molten mixture in a molten state is cooled to a temperature below the melting point to solidify, and the composite formed thereby may be in a solid state. More preferably, the composite may be a solid powder obtained through an additional grinding process, etc.

Meanwhile, the step of melting and mixing the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 and solidifying the melted mixture to form a complex may include a step of mixing the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 at a temperature of 50° C. or higher; and a step of cooling the resultant of the mixing step.

The above terephthaloyl chloride has a melting point of 81.3° C. to 83° C., the above isophthaloyl chloride has a melting point of 43° C. to 44° C., and the above phthaloyl chloride may have a melting point of 6° C. to 12° C. Accordingly, when these are mixed at a temperature of 50° C. or higher, or 90° C. or higher, or 50° C. to 120° C., or 90° C. to 120° C., or 95° C. to 110° C., or 100° C. to 110° C., melt mixing may proceed because it is a temperature condition higher than the melting points of both the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8.

In the step of cooling the result of the above mixing step, by leaving the result of the above melting and mixing step at 5° C. or lower, or -10° C. to 5° C., or -5° C. to 5° C., since this is a temperature condition lower than the melting points of both the compound represented by the above chemical formula 7 and the compound represented by the above chemical formula 8, a more uniform solid powder can be obtained through cooling.

Meanwhile, after the step of cooling the result of the mixing step, a step of pulverizing the result of the cooling step may be further included. Through the pulverizing step, the solid composite can be manufactured in a powder form, and the powder obtained after the pulverizing step can have an average particle size of 1 mm to 10 mm.

The crusher used to crush into such particle sizes may specifically include a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill, a jog mill, or a sieve or jaw crusher, but is not limited to the examples described above.

In this way, by reacting the molten mixture of the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 with an aromatic diamine monomer in the form of a solid, specifically, a solid powder, through cooling at a temperature lower than the melting point, the deterioration of the compound represented by the chemical formula 7 and the compound represented by the chemical formula 8 due to moisture or mixing with a solvent is minimized, thereby improving the molecular weight of the polyamide resin finally synthesized, and thus excellent mechanical properties of the polymer film can be secured.

In addition, the method for producing the polyamide resin may include a step of melting and mixing a compound represented by the chemical formula 7 and a compound represented by the chemical formula 8, solidifying the melted mixture to form a complex, and then a step of reacting the complex with an aromatic diamine monomer.

The reaction in the step of reacting the above complex with an aromatic diamine monomer can be performed under a temperature condition of -25° C. to +25° C., or a temperature condition of -25° C. to 0° C., under an inert gas atmosphere.

The above aromatic diamine monomers include, specifically, for example, 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine, 2,2'-dimethyl-4,4'-diaminobenzidine, 4,4'-diaminodiphenyl sulfone, 4,4'-(9-fluorenylidene)dianiline, bis(4-(4-aminophenoxy)phenyl)sulfone, 2,2',5,5'-tetrachlorobenzidine, 2,7-diaminofluorene, 4,4-diaminooctafluorobiphenyl, m-phenylenediamine, p-phenylenediamine, 4,4'-oxydianiline, 2,2'-dimethyl-4,4'-diaminobiphenyl, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis(4-aminophenoxy)benzene, m-xylylenediamine, p-xylylenediamine, and It may include at least one selected from the group consisting of 4,4'-diaminobenzanilide.

More preferably, the aromatic diamine monomer may be 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (TFDB), 2,2'-dimethyl-4,4'-diaminobenzidine, m-xylylenediamine, or p-xylylenediamine.

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 preparing a diamine solution by dissolving the above aromatic diamine monomer in an organic solvent, the aromatic diamine monomer included in the diamine solution may exist in a state dissolved in the organic solvent. Examples of the solvent are not particularly limited, but for example, N-methylformamide, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N,N-dimethylpropionamide, 3-methoxy-N,N-dimethylpropionamide, dimethyl sulfoxide, acetone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, tetrahydrofuran, chloroform, gamma-butyrolactone, ethyl lactate, methyl 3-methoxypropionate, methyl isobutyl ketone, toluene, xylene, methanol, ethanol, and other general-purpose organic solvents may be used without limitation.

In the step of adding the complex powder to the above diamine solution, the complex powder reacts with the aromatic diamine monomer dissolved in the diamine solution. Accordingly, the molecular weight of the polyamide resin finally synthesized is improved by minimizing the deterioration due to moisture of the compound represented by the above chemical formula 7 and the compound represented by the above chemical formula 8, thereby ensuring excellent mechanical properties of the polymer film.

The above complex powder can be manufactured in the form of a solid complex powder through a step of pulverizing the result of the cooling step after the step of cooling the result of the mixing step, and the powder obtained after the pulverizing step can have an average particle size of 1 mm to 10 mm.

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

When a polymer film is manufactured using the polyamide resin described above, it can have excellent optical and mechanical properties while also being flexible, so that it can be used as a material for various molded products. For example, the polymer film can be applied to a substrate for a display, a protective film for a display, a touch panel, a window cover for a foldable device, etc.

The thickness of the polymer film is not particularly limited, but can be freely adjusted within a range of, for example, 0.01 ㎛ to 1000 ㎛. When the thickness of the polymer film increases or decreases by a specific value, the physical properties measured in the polymer film can also change by a specific value.

The above polymer film can be manufactured by a conventional method such as a dry method or a wet method using the above-described polyamide resin. For example, the above polymer film can be obtained by a method of forming a film by coating a solution containing the above-described polymer or polyamide resin on any support, and evaporating the solvent from the film to dry it. If necessary, the polymer film can be further subjected to stretching and heat treatment.

The above polymer film can exhibit excellent mechanical properties while being colorless and transparent as it is manufactured using the above-described polyamide resin.

Specifically, the polymer film may have a haze value of 3.0% or less, or 1.5% or less, or 1.00% or less, or 0.85% or less, or 0.10% to 3.0%, or 0.10% to 1.5%, or 0.10% to 1.00%, or 0.50% to 1.00%, or 0.80% to 1.00%, or 0.81% to 0.97%, as measured according to ASTM D1003 for a specimen having a thickness of 50 ± 2 ㎛. If the haze of the polymer film measured according to ASTM D1003 increases to more than 3.0%, opacity increases and it is difficult to secure a sufficient level of transparency.

And, the polymer film may have a yellow index (YI) value of 4.0 or less, or 3.0 or less, or 0.5 to 4.0, or 0.5 to 3.0, as measured according to ASTM E313 for a specimen having a thickness of 50 ± 2 ㎛. If the yellow index (YI) value of the polymer film measured according to ASTM E313 increases to more than 4.0, the opacity increases and it is difficult to secure a sufficient level of transparency.

And, the polymer film may have a transmittance (T, @550nm) for visible light having a wavelength of 550 nm of 86% or more, or from 86% to 90%, for a specimen having a thickness of 50 ± 2 ㎛, and a transmittance (T, @388nm) for ultraviolet light having a wavelength of 388 nm of 50.00% or more, or from 60.00% or more.

And, the polymer film may have a tensile strength (number of reciprocating bends to break at an angle of 135°, a radius of curvature of 0.8 mm, and a load of 250 g at a speed of 175 rpm) measured for a specimen having a thickness of 50 ± 2 ㎛ of 4000 Cycles or more, 7000 Cycles or more, or 9000 Cycles or more, or 4000 to 20000 Cycles, or 7000 to 20000 Cycles, or 9000 to 20000 Cycles.

And, the polymer film may have a pencil hardness value of 1H or more, 3H or more, or from 1 H to 4H, or from 3 H to 4H, as measured according to ASTM D3363 for a specimen having a thickness of 50 ± 2 ㎛.

Ⅱ. Method for manufacturing polymer film

According to another embodiment of the invention, a method for manufacturing a polymer film can be provided, comprising the steps of forming a coating film by applying a composition including a polyamide resin having an average particle diameter of individual crystals of 8.0 nm or less as measured by a small-angle X-ray scattering device, to a substrate film having 4/0.3 ㎟ or less surface protrusions having a maximum height of 100 nm or more.

As described above, the substrate film may include surface roughness including surface grooves or surface protrusions.

Specifically, the surface roughness may mean a concave portion or a protrusion from an average plane having an average height of the substrate film.

More specifically, the surface groove may mean a concave portion from an average plane having an average height of the substrate film, and the surface protrusion may mean a protrusion from an average plane having an average height of the substrate film.

Additionally, the maximum height may mean the distance from an average plane having an average height of the above-mentioned substrate film to the highest point of the surface protrusion.

That is, the surface protrusion having the maximum height of 100 nm or more may mean a surface roughness, which is a surface protrusion having an average surface (average height) calculated in a measurement area of the substrate film (0.3 ㎟, for example, a substrate film specimen measuring 0.6 mm in width x 0.5 mm in height), and a maximum distance from the average surface to the highest point of the protrusion is 100 nm or more.

Meanwhile, the measurement area of the surface protrusion is not particularly limited, and may be, for example, one surface of the substrate film. That is, the surface protrusion having the maximum height of 100 nm or more may mean a surface protrusion having a distance of 100 nm or more from an average plane having an average height of one surface of the substrate film as the measurement area to the highest point of the surface protrusion.

Specifically, one surface of the substrate film may be one of the surfaces perpendicular to the thickness direction of the substrate film. The thickness direction refers to the direction in which the thickness of the substrate film increases, and the surface protrusion may be measured for the outermost surface of the substrate film perpendicular to the thickness direction.

For example, when the substrate film is assumed to have a hexahedral shape having a width, length, and thickness, the surfaces perpendicular to the thickness direction of the substrate film can be the upper and lower surfaces facing each other across the thickness.

More specifically, one surface of the substrate film may refer to the surface of the substrate film on which a composition including a polyamide resin is applied in the method for manufacturing a polymer film described below.

In a method for manufacturing a polymer film, which includes the step of forming a coating film by applying a composition containing a polyamide resin to a substrate film, described below, when the surface on which the composition containing the polyamide resin is applied is used as a measurement area, the number of surface irregularities having a maximum height of 100 nm or more may be 4/0.3 ㎟ or less.

The content regarding the above polymer film and polyamide resin may include all of the content described above in the above embodiment.

The above-described substrate film may have a number of surface protrusions having a maximum height of 100 nm or more of 4/0.3 ㎟ or less, 0/0.3 ㎟ or more and 4/0.3 ㎟ or less, 0/0.3 ㎟ or more and 3/0.3 ㎟ or less, 0/0.3 ㎟ or more and 2/0.3 ㎟ or less, 0/0.3 ㎟ or more and 1/0.3 ㎟ or less, or 0/0.3 ㎟.

The method for manufacturing the above polymer film includes a step of forming a coating film by applying a composition containing a polyamide resin to a base film, and as in the above embodiment, by using a base film having 4/0.3㎟ or less surface protrusions having a maximum height of 100 nm or more, the number of surface grooves having a maximum depth of 100 nm or more of the polymer film finally manufactured can satisfy 4/0.3㎟ or less.

The number of surface protrusions of the above-described film can be measured by the same method as the method for measuring the number of surface grooves of the polymer film described above.

The type of the above-mentioned substrate film is not particularly limited, but may be, for example, a polyethylene terephthalate substrate film.

More specifically, the substrate film may contain less than 0.0001 wt % of the filler. Containing less than 0.0001 wt % of the filler may mean that the substrate film does not contain any filler at all. When the substrate film contains less than 0.0001 wt % of the filler, the number of surface protrusions having a maximum height of 100 nm or more of the substrate film may be 4/0.3 mm2 or less, 0/0.3 mm2 or more and 4/0.3 mm2 or less, 0/0.3 mm2 or more and 3/0.3 mm2 or less, 0/0.3 mm2 or more and 2/0.3 mm2 or less, 0/0.3 mm2 or more and 1/0.3 mm2 or less, or 0/0.3 mm2.

The composition containing the above polyamide resin may be obtained by dissolving or dispersing the above-described polyamide resin in an organic solvent. Specific examples of the organic solvent include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, 2-pyrrolidone, N-ethylpyrrolidone, N-vinylpyrrolidone, dimethylsulfoxide, tetramethylurea, pyridine, dimethylsulfone, hexamethylsulfoxide, γ-butyrolactone, 3-methoxy-N,N-dimethylpropanamide, 3-ethoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, 1,3-dimethyl-imidazolidinone, ethylamyl ketone, methylnonyl ketone, methyl ethyl ketone, methyl isoamyl ketone, methyl isopropyl ketone, cyclohexanone, ethylene carbonate, propylene carbonate, diglyme, Examples thereof include 4-hydroxy-4-methyl-2-pentanone, ethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol monopropyl ether, ethylene glycol monopropyl ether acetate, ethylene glycol monoisopropyl ether, ethylene glycol monoisopropyl ether acetate, ethylene glycol monobutyl ether, and ethylene glycol monobutyl ether acetate. These may be used alone or in combination.

The method for applying the composition containing the above polyamide resin is not particularly limited, and for example, methods such as screen printing, offset printing, flexographic printing, and inkjet printing can be used.

Meanwhile, the method for manufacturing a polymer film of the above embodiment may further include a step of drying a film formed by applying a composition including the polyamide resin to a substrate.

The drying step of the above film can be performed by a heating means such as a hot plate, a hot air circulator, an infrared furnace, etc., and can be performed at a temperature of 50°C to 130°C, or 70°C to 130°C.

In addition, the method for manufacturing a polymer film of the above embodiment may further include a step of applying a composition including the polyamide resin to a substrate and drying a coating film formed therefrom; and then a step of heat-treating and curing the dried coating film to form a polymer film.

The above heat treatment can be performed by a heating means such as a hot plate, a hot air circulator, or an infrared furnace, and can be performed at a temperature of 100°C to 300°C, or 200°C or higher and 300°C or lower.

In addition, the method for manufacturing a polymer film of the above embodiment may further include a step of heat-treating the dried coating film to harden it and form a polymer film; and then, a step of peeling off the polymer film.

The method for manufacturing a polymer film of the present invention uses a substrate having 4 or fewer unevennesses having protrusions having a maximum height of 100 nm or more based on the surface of a substrate specimen measuring 0.6 mm in width and 0.5 mm in length, so that in the step of peeling off the polymer film, peeling between the substrate and the polymer film can be facilitated.

Ⅲ. Resin laminate

According to another embodiment of the invention, a resin laminate including a substrate including the above-described polymer film; and a hard coating layer formed on at least one surface of the substrate can be provided.

The content regarding the above polymer film may include all of the content described above in the above embodiment.

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

The above hard coating layer may have a thickness of 0.1 μm to 100 μm.

The hard coating layer may be made of any material known in the hard coating field without any particular limitations. For example, the hard coating layer may include a binder resin of a photocurable resin; and inorganic particles or organic particles dispersed in the binder resin.

The photocurable resin included in the hard coating layer may be a polymer of a photocurable compound that can cause a polymerization reaction when irradiated with light such as ultraviolet rays, and may be a polymer commonly used in the art. However, preferably, the photocurable compound may be a multifunctional (meth)acrylate-based monomer or oligomer, and in this case, the number of (meth)acrylate-based functional groups is 2 to 10, or 2 to 8, or 2 to 7, which is advantageous in terms of securing the physical properties of the hard coating layer. 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, torylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, trimethylolpropane tri(meth)acrylate, and trimethylolpropane polyethoxy tri(meth)acrylate.

The above inorganic particles may be, for example, metal atoms such as silica, aluminum, titanium, zinc, or oxides, nitrides, etc. thereof, and silica fine particles, aluminum oxide particles, titanium oxide particles, zinc oxide particles, etc. may be used independently.

The above-mentioned inorganic particles may have an average radius of 100 nm or less, or 5 to 100 nm. The type of the above-mentioned organic particles is also not limited, and for example, polymer particles having an average particle diameter of 10 nm to 100 ㎛ may be used.

The above resin laminate can be used as a substrate or cover window of a display device, and has high flexibility and bending durability along with high light transmittance and low haze characteristics, so it can be used as a substrate or cover window of a flexible display device. That is, a display device including the resin laminate, or a flexible display device including the resin laminate can be implemented.

According to the present invention, a polymer film, a method for producing a polymer film, and a resin laminate can be provided in which optical properties such as transparency are improved by significantly reducing surface roughness, while mechanical properties above an appropriate level are secured.

Figure 1 is a schematic diagram of the crystal structure of the polyamide resin of Example 1.
Figure 2 shows the ¹³ C-NMR spectrum of the polyamide resin of Example 1.
Figure 3 shows the ¹³ C-NMR spectrum of the polyamide resin of Example 2.
Figure 4 is a photograph of the polymer film of Example 1 taken using an Optical Profiler.
Figure 5 is a photograph of the polymer film of Comparative Example 4 taken using an Optical Profiler.

The invention is described in more detail in the following examples. However, the following examples are only intended to illustrate the present invention, and the content of the present invention is not limited by the following examples.

<Manufacturing Example: Manufacturing of Acyl Chloride Complex>

Manufacturing example 1

In a 1000 mL 4-neck round bottom flask (reactor) equipped with a stirrer, a nitrogen injector, a dropping funnel, and a temperature controller, 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, melted and mixed at 100°C for 3 hours, and then cooled at 0°C for 12 hours to prepare a complex of acyl chlorides (specifically, terephthaloyl chloride and isophthaloyl chloride).

Thereafter, the acyl chloride complex was crushed using a jaw crusher to produce a powder with an average particle size of 5 mm.

Manufacturing example 2

An acyl chloride complex powder was prepared in the same manner as in Manufacturing 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: Manufacturing of polymer film>

Example 1

A 500 mL 4-neck round bottom flask (reactor) equipped with a stirrer, a nitrogen injector, a dropping funnel, and a temperature controller was slowly filled with nitrogen while charging 262 g of N,N-dimethylacetamide (DMAc), and after adjusting the temperature of the reactor to 0°C, 14.153 g (0.0442 mol) of 2,2'-bis(trifluoromethyl)-4,4'-biphenyl diamine (TFDB) was dissolved.

Here, 8.972 g (0.0442 mol) of the acyl chloride complex powder obtained in the abovementioned Manufacturing Example 1 was added and stirred, and the amide formation reaction was performed for 12 hours at 0°C.

After the reaction was completed, N,N-dimethylacetamide (DMAc) was added to dilute the solid content to 5% or less, precipitated with 1 L of methanol, and the precipitated solid was filtered and dried in a vacuum at 100°C for more than 6 hours to produce a polyamide resin in solid form.

Through ^{the 13} C-NMR described in FIG. 2 below, it was confirmed that the polyamide resin obtained above contains 82 mol% of the first repeating unit obtained by the 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 the amide reaction of isophthaloyl chloride (IPC) and 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (TFDB).

The polyamide resin obtained above was dissolved in N,N-dimethylacetamide to prepare a polymer solution of about 10% (w/V).

The above polymer solution was applied onto a polyethylene terephthalate base film (A4160, Toyobo) containing 0 wt% filler (Silica), and the thickness of the polymer solution was uniformly controlled using a film applicator.

Afterwards, the film was dried in an 80°C Matiz oven for 15 minutes, cured at 250°C for 30 minutes while flowing nitrogen, and then peeled off from the substrate film to obtain a polymer film.

Example 2

A polyamide resin was manufactured in the same manner as in Example 1, except that the acyl chloride complex powder obtained in Manufacturing Example 2 was used instead of the acyl chloride complex powder obtained in Manufacturing Example 1.

Through ^{the 13} C-NMR described in FIG. 3 below, it was confirmed that the polyamide resin obtained above contains 85 mol% of the first repeating unit obtained by the 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 the amide reaction of isophthaloyl chloride (IPC) and 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (TFDB).

Using the polyamide resin obtained above, a polymer film was obtained in the same manner as in Example 1.

<Comparative Example: Manufacturing of Polymer Film>

Comparative Example 1

A polyamide resin and a polymer film were manufactured in the same manner as in Example 1, except that instead of the acyl chloride complex powder obtained in Manufacturing 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 the amide formation reaction.

Comparative Example 2

A polyamide resin and a polymer film were manufactured in the same manner as in Example 1, except that instead of the acyl chloride complex powder obtained in Manufacturing 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 sequentially added at intervals of about 5 minutes to perform the amide formation reaction.

Comparative Example 3

A polyamide resin and a polymer film were manufactured in the same manner as in Example 1, except that instead of the acyl chloride complex powder obtained in Manufacturing Example 1, 1.615 g (0.0080 mol) of isophthaloyl chloride (IPC) was first added, and then 7.358 g (0.0362 mol) of terephthaloyl chloride (TPC) was sequentially added at intervals of about 5 minutes to perform the amide formation reaction.

Comparative Example 4

A 500 mL 4-neck round bottom flask (reactor) equipped with a stirrer, a nitrogen injector, a dropping funnel, and a temperature controller was slowly filled with nitrogen while charging 262 g of N,N-dimethylacetamide (DMAc), and after adjusting the temperature of the reactor to 0°C, 14.153 g (0.0442 mol) of 2,2'-bis(trifluoromethyl)-4,4'-biphenyl diamine (TFDB) was dissolved.

Here, 8.972 g (0.0442 mol) of the acyl chloride complex powder obtained in the abovementioned Manufacturing Example 1 was added and stirred, and the amide formation reaction was performed for 12 hours at 0°C.

After the reaction was completed, N,N-dimethylacetamide (DMAc) was added to dilute the solid content to 5% or less, precipitated with 1 L of methanol, and the precipitated solid was filtered and dried in a vacuum at 100°C for more than 6 hours to produce a polyamide resin in solid form.

Through ^{the 13} C-NMR described in FIG. 2 below, it was confirmed that the polyamide resin obtained above contains 82 mol% of the first repeating unit obtained by the 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 the amide reaction of isophthaloyl chloride (IPC) and 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (TFDB).

The polyamide resin obtained above was dissolved in N,N-dimethylacetamide to prepare a polymer solution of about 10% (w/V).

The above polymer solution was applied onto a polyethylene terephthalate base film (MRF125, Mitsubishi Chemical Company) containing 0.1 wt% filler (Silica), and the thickness of the polymer solution was uniformly controlled using a film applicator.

Afterwards, the film was dried in an 80°C Matiz oven for 15 minutes, cured at 250°C for 30 minutes while flowing nitrogen, and then peeled off from the substrate film to obtain a polymer film.

<Experimental Example 1>

The characteristics of individual crystals contained in the polyamide resins obtained in the above examples and comparative examples were measured using small-angle X-ray scattering (SAXS), and the results are shown in Table 1 below.

Using the polyamide resin obtained in the above examples and comparative examples, samples measuring 1 cm in width and 1 cm in length were prepared, and the samples were set in a small-angle X-ray scattering device (PLS-9A USAXS beam line) with a camera length of 2.5 m and 6.5 m at room temperature (23°C), and X-rays having energies of 11.1 KeV and 19.9 KeV were irradiated to obtain a scattering pattern. The scattering pattern was then analyzed using analysis equipment (NIST SANS package) equipped on the small-angle X-ray scattering device to obtain the average particle diameter (2Rc), dimensionality, and crystallinity of individual crystals.

Specifically, the average particle diameter, dimensionality, and crystallinity of the individual crystals are analyzed using data acquired from a small-angle X-ray scattering device (PLS 9A beamline) via a computer program (NIST SANS package), and more specifically, the average particle diameter of the individual crystals is obtained by fitting the shape of the individual crystals contained in the sample to a solid sphere model, and the plot of the wavenumber q (unit: Å ^-1 ) and the scattering intensity I (unit: au) is convolved with the Schulz-Zimm distribution, and can be obtained through calculations using a computer program (NIST SANS package).

Average particle size of the decision (nm) Dimensionality Crystallinity (%) Example 1 5.0 3.7 Difficult to measure below 20% Example 2 6.8 - Difficult to measure below 20% Comparative Example 1 8.4 4.0 Difficult to measure below 20% Comparative Example 2 13.4 3.2 24 Comparative Example 3 8.1 - Difficult to measure below 20%

As shown in Table 1 above, the average particle diameter of the individual crystals contained in the polyamide resin obtained in the examples was measured to be small, ranging from 5 nm to 6.8 nm, whereas the average particle diameter of the individual crystals contained in the polyamide resin obtained in Comparative Example 1 was 8.4 nm, the average particle diameter of the individual crystals contained in the polyamide resin obtained in Comparative Example 2 was 13.4 nm, and the average particle diameter of the individual crystals contained in the polyamide resin obtained in Comparative Example 3 was 7.8 nm, which were confirmed to have increased compared to the examples. In addition, the crystallinity of the polyamide resin obtained in the examples showed low crystal characteristics, less than 20%, whereas the crystallinity of the polyamide resin obtained in Comparative Example 2 was 24%, which was confirmed to have increased compared to the examples.

Through this, it was confirmed that the polyamide resin obtained in the above example had a crystalline block length growth suppressed compared to the comparative example, which was composed of repeating units obtained by the amide reaction of terephthaloyl chloride (TPC) and 2,2'-bis(trifluoromethyl)-4,4'-biphenyldiamine (TFDB).

<Experimental Example 2>

The properties below were measured or evaluated for the polyamide resin or polymer film obtained in the above examples and comparative examples, and the results are shown in Table 2 below.

(1) Thickness

The thickness of the polymer film was measured using a thickness measuring device.

(2) Yellow Index (Y.I.)

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

(3) Light transmittance

Total light transmittance of the polymer film was measured using a Shimadzu UV-2600 UV-vis spectrometer. The measurement results show the transmittance for ultraviolet light with a wavelength of 388 nm (T, @388nm) and the transmittance for visible light with a wavelength of 550 nm (T, @550nm).

(4) Haze

The haze value of the polymer film was measured using a COH-400 Spectrophotometer (NIPPON DENSHOKU INDUSTRIES) according to the measurement method of ASTM D1003.

(5) Molecular weight and molecular weight distribution (PDI, polydispersity index)

The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the polyamide resin were measured using gel permeation chromatography (GPC, manufactured by Waters), and the molecular weight distribution (PDI) was calculated by dividing the weight-average molecular weight by the number-average molecular weight. Specifically, a 600-mm column composed of two 300-mm columns of Polymer Laboratories PLgel MIX-B was used, and the evaluation temperature was 50 to 75 °C (approximately 65 °C), a 100 wt% DMF solvent was used, the sample was prepared at a concentration of 1 mg/mL, and then 100 μL was supplied for 25 minutes. The molecular weight was obtained using a calibration curve formed using a polystyrene standard. The molecular weights of polystyrene standards were 7 types: 3940 / 9600 / 31420 / 113300 / 327300 / 1270000 / 4230000.

(6) Flexibility

The folding endurance of the polymer film was evaluated using a MIT type folding endurance tester. Specifically, a specimen (1 cm*7 cm) of the polymer film was loaded into the folding endurance tester, and the specimen was bent at a speed of 175 rpm at an angle of 135°, a radius of curvature of 0.8 mm, and a load of 250 g on the left and right sides, and the number of reciprocating bending cycles until fracture was measured.

(7) Relative viscosity

Using a 25±0.2℃ constant temperature reflux system, a solution containing polyamide resin (solvent: dimethylacetamide (DMAc), solid content 10 wt%) was measured using a Brookfield viscometer DV-2T according to the rotational viscometer test method for non-Newtonian substances of ASTM D 2196, and a number of standard solutions with a viscosity range of 5000 cps to 200000 cps using Brookfield's silicone oil as a standard material, at spindle LV-4 (64), 0.3 to 100 RPM, and the unit was cps (mPa.s).

(8) Pencil hardness

The pencil hardness of the polymer film was measured using a Pencil Hardness Tester according to the measurement method of ASTM D3363. Specifically, pencils of various hardness were fixed to the tester and scratched on the polymer film. The degree of scratching on the polymer film was observed with the naked eye or under a microscope. When no scratches occurred for more than 70% of the total number of scratches, the value corresponding to the hardness of the pencil was evaluated as the pencil hardness of the polymer film.

The above pencil hardness increases in the order of B grade, F grade, and H grade, and within the same grade, the harder the number, the higher the hardness.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Thickness (㎛) 50 49 51 51 50 Y.I. 2.68 2.89 8.55 25.10 4.59 T (%)@550nm 88.75 88.50 85.63 75.94 87.57 T (%)@388nm 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 Cycle 12022 9785 5210 785 4513 PDI 1.84 2.71 2.05 2.02 1.98 Viscosity (cps) 110000 174000 54000 24000 28000 Pencil hardness 3H 4H 1H F 1H

Looking at Table 2 above, the polyamide resin of the example manufactured using the acyl chloride complex powder according to Manufacturing Examples 1 and 2 has a high weight average molecular weight of 463,000 to 512,000 g/mol, and a high relative viscosity of 110,000 to 174,000 cps. In addition, in the case of the polymer film obtained from the polyamide resin of the example, it was confirmed that excellent transparency was secured through a low yellow index of 2.68 to 2.89 and a low haze value of 0.81% to 0.97% at a thickness of approximately 50 ㎛, and excellent mechanical properties (scratch resistance and bending strength) were secured through a high pencil hardness of 3H to 4H grade and a break strength at a reciprocating bending number (cycle) of 9785 to 12022.

On the other hand, the polyamide resins of Comparative Examples 1 to 3, in which the acyl chloride complex powder according to Manufacturing Examples 1 to 2 was not used at all in the polyamide resin synthesis process, had a molecular weight decreased from 321,000 g/mol to 412,000 g/mol compared to the examples, and a viscosity decreased from 18,000 cps to 54,000 cps compared to the examples.

On the other hand, in the case of 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 introduced, respectively, the yellowness index was 3.14 to 23.59 and the haze value was 1.61% to 24.21% at a thickness of approximately 50 ㎛, which was higher than in the example, confirming poor transparency. This is thought to be because, in the case of Comparative Examples 1, 2, and 3, blocks were excessively formed by TPC due to differences in solubility and reactivity between the TPC powder and the IPC powder, which increased the crystallinity of the polyamide resin.

<Experimental Example 3>

(1) Surface characteristics of polymer films

For the polymer films obtained in the above examples and comparative examples, specimens were made by arbitrarily cutting them to 5 cm in width and 5 cm in length, and the specimens were positioned on the Optical Profiler so that the PET film side was measured. Then, the magnification was adjusted to 10 times so that a measurement area of 0.6 mm in width and 0.5 mm in length was measured, and the number of surface grooves with a maximum depth of 100 nm or more was measured using NV-2700 (manufacturer: Nano System), and the results are shown in Table 3 below.

(2) Surface characteristics of the substrate film

For the base film used in the above examples and comparative examples, a specimen was made by arbitrarily cutting it to 5 cm in width and 5 cm in length, and the specimen was positioned on an Optical Profiler so that the side coated with the polymer film was measured. Then, the magnification was adjusted to 10 times so that a measurement area of 0.6 mm in width and 0.5 mm in length was measured, and the number of surface protrusions with a maximum height of 100 nm or more was measured using NV-2700 (manufacturer: Nano System), and the results are shown in Table 3 below.

(3) Arithmetic mean roughness (Ra)

For the polymer film used in the above examples and comparative examples, a specimen measuring 0.6 mm in width and 0.5 mm in length was manufactured, and the arithmetic mean roughness (Ra) of the surface of the polymer film calculated by the following mathematical formula 1 was measured using an Optical Profiler according to JIS B0601-1994.

[Mathematical formula 1]

In the above mathematical expression 1, L is the reference length, and f(x) represents the deviation of the roughness curve from the mean line.

division Example 1 Example 2 Comparative Example 4 Number of surface grooves with a maximum depth of 100 nm or more in a polymer film 0 0 5 or more The number of surface protrusions having a maximum height of 100 nm or more on the substrate film 0 0 5 or more Arithmetic mean roughness (Ra) 5 nm 5 nm 30nm

As shown in Table 3 above, the number of surface protrusions having a maximum height of 100 nm or more in the base film of the example was 0/0.3㎟, and thus it was confirmed that the polymer films of Examples 1 and 2, which were manufactured by applying the polyamide resin of the example manufactured using the acyl chloride complex powder according to Manufacturing Examples 1 and 2 on the base film, also measured the number of surface grooves having a maximum depth of 100 nm or more as 0/0.3㎟.

In addition, since the polymer films of Examples 1 and 2 had 0/0.3㎟ of surface grooves with a maximum depth of 100 nm or more, the arithmetic mean roughness (Ra) was measured to be 10 nm or less, confirming that the surface unevenness was significantly reduced.

On the other hand, in the case of Comparative Example 4, since a base film containing filler was used, the number of surface protrusions having a maximum height of 100 nm or more of the base film was 5/0.3㎟ or more, and accordingly, it was confirmed that the polymer film of Comparative Example 4 also had a number of surface grooves having a maximum depth of 100 nm or more of 5/0.3㎟ or more.

In addition, since the polymer film of Comparative Example 4 had 5 or more surface grooves/0.3㎟ with a maximum depth of 100 nm or more, the arithmetic mean roughness (Ra) was measured to be 30 nm, confirming that the film excessively included surface irregularities.

1: Individual decision
2: Average particle size of individual decisions
3: Amorphous polymer chain

Claims (20)

Comprising a polyamide resin having an average particle size of individual crystals of 8.0 nm or less as measured by an incineration X-ray scattering device,
Between the individual crystals having an average particle diameter of 8.0 nm or less, amorphous polymer chains exist,
The individual crystals having an average particle diameter of 8.0 nm or less include a first polyamide segment including a repeating unit represented by the following chemical formula 1, or a block composed of the same,
An amorphous polymer chain present between individual crystals having an average particle diameter of 8.0 nm or less, including a first polyamide segment comprising a repeating unit represented by the above chemical formula 1, or a block comprised thereof, and a second polyamide segment comprising a repeating unit represented by the following chemical formula 2, or a block comprised thereof,
The first polyamide segment and the second polyamide segment form a main chain including a cross-repeating unit represented by the following chemical formula 3,
A polymer film having a number of surface grooves having a maximum depth of 100 nm or more formed on the polymer film of 4/0.3 ㎟ or less:
[Chemical formula 1]

In the above chemical formula 1, Ar 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,
[Chemical formula 2]

In the above chemical formula 2,
Ar 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,
[Chemical formula 3]

In the above chemical formula 3,
A is the first polyamide segment,
B is the second polyamide segment.

In the first paragraph,
A polymer film having an arithmetic mean roughness of 10 nm or less.
In the first paragraph,
The number of surface grooves above is,
A polymer film, the measurement being made on one surface perpendicular to the thickness direction of the polymer film.
In the first paragraph,
The average particle size of the above individual decisions is
A polymer film, which is obtained by irradiating X-rays having an energy of 10 KeV to 20 KeV in the above-mentioned small-angle X-ray scattering device with a scattering pattern, fitting the obtained scattering pattern to a solid sphere model, and measuring the obtained scattering pattern using an analysis device.
delete In the first paragraph,
A polymer film wherein the distance between individual crystals having an average particle size of 8.0 nm or less is 0.1 nm to 100 nm.
delete delete delete In the first paragraph,
A polymer film, wherein the first polyamide segment has a number average molecular weight of 100 g/mol to 5000 g/mol.
In the first paragraph,
A polymer film comprising 40 mol% to 95 mol% of the first polyamide segment based on all repeating units contained in the polyamide resin.
In the first paragraph,
A polymer film having a crystallinity of 20% or less as measured by a small-angle X-ray scattering device.
delete delete In the first paragraph,
A polymer film having a haze of 0.45% or less as measured by ASTM D1003 for specimens having a thickness of 45 ㎛ or more and 55 ㎛ or less.
In the first paragraph,
A polymer film, wherein the weight average molecular weight of the polymer is 330,000 g/mol to 1,000,000 g/mol.
In the first paragraph,
A polymer film having a content of repeating units represented by the chemical formula 2 of 5 mol% to 60 mol% based on all repeating units contained in the polyamide resin.
In the first paragraph,
The cross-repeating unit represented by the above chemical formula 3 is a repeating unit represented by the following chemical formula 4, a polymer film:
[Chemical formula 4]

In the above chemical formula 4,
Ar ₁ and Ar 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 from 1 to 10,
b1 and b2 are each independently an integer from 1 to 5.
A step for producing a polyamide resin, comprising the steps of melting and mixing a compound represented by the following chemical formula 7 and a compound represented by the following chemical formula 8, solidifying the melted mixture to form a complex, and reacting the complex with an aromatic diamine monomer; and
A method for manufacturing a polymer film according to claim 1, comprising: forming a coating film by applying a composition including the polyamide resin, wherein the average particle size of individual crystals measured by a small-angle X-ray scattering device is 8.0 nm or less, to a base film having a number of surface protrusions having a maximum height of 100 nm or more and 4/0.3㎟ or less;
[Chemical formula 7]

[Chemical formula 8]

In the above chemical formulas 7 to 8, X is a halogen or a hydroxyl group.
A substrate including a polymer film of claim 1; and
A resin laminate comprising a hard coating layer formed on at least one surface of the above-described substrate.

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