KR20220160176A - Transparent hybrid film containing fumed silica nanoparticles and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a transparent hybrid film containing fumed silica nanoparticles and a manufacturing method thereof. Specifically, the present invention provides a transparent hybrid film comprising: a fluorine-based polyamide-imide polymer copolymerized with a unit structure derived from a diamine compound, a unit structure derived from a dianhydride compound, and a unit structure derived from terephthaloyl chloride (TPC, 1,4-benzene dicarbonyl chloride); and fumed silica nanoparticles, wherein 1-5 parts by weight of the fumed silica nanoparticles are contained based on the total solid weight of the polyamide-imide polymer. The transparent hybrid film provided according to one aspect of the present invention can form a film with maintained transparency and improved hardness, elastic modulus, and tensile strength by adding the fumed silica nanoparticles to the fluorine-based polyamide-imide polymer.

Description

Transparent hybrid film containing fumed silica nanoparticles and method for manufacturing the same}

The present invention relates to a transparent hybrid film comprising fumed silica nanoparticles and a manufacturing method thereof.

Recently, touch screen panels using fingers, such as smart phones and tablet PCs, are widely used in daily life and industrial fields. Most touch screen panels use tempered glass with strong strength and scratch resistance as a cover window, but it has disadvantages that it is not suitable for portable devices and flexible displays due to its heavy weight and insufficient flexibility.

In order to compensate for these disadvantages, plastic cover windows are attracting attention. In general, a transparent plastic cover window is made of polyethylene terephthalate (PET), polycarbonate (PC), polyimide (PI), polyamideimide (PAI), or the like, and has excellent flexibility compared to tempered glass. However, compared to tempered glass, it lacks physical properties such as impact resistance and scratch resistance. It is difficult for a transparent plastic film to simultaneously satisfy both mechanical and optical properties required for use as a cover window of a display device.

In order to solve this problem, various attempts have been made to compensate for the insufficient surface hardness of the transparent plastic film by using coating agents using various resins. However, the mechanical properties of the transparent plastic itself, which is the basis of the plastic protective window, are not improved, and there is a limit to improving the mechanical properties of the plastic protective window only by using a coating agent. As an alternative to this, a transparent plastic film using an organic/inorganic hybrid material is proposed.

Although most of the inorganic materials used in the production of transparent organic/inorganic hybrid films vary in degree depending on the size of the particles and the manufacturing method of the particles, when a large amount is introduced, the haze of the film due to aggregation of the inorganic materials It is revealing an increasing limit, and a technology that can further improve compatibility with polymers is required. As a method of improving the dispersibility of inorganic substances in polymers, there are physical methods using a miller, mixer, high-speed stirrer, homogenizer, ultrasonic disperser, etc., and chemical modification methods that graft organic substances that have affinity with polymers to the surface of inorganic substances. have.

As a kind of organic/inorganic hybrid film, the present inventors added fumed silica nanoparticles without surface modification to fluorine-based transparent polyamide-imide in a specific amount and stably dispersed, thereby increasing the transparency of the fluorine-based polyamide-imide film. The present invention was completed by developing a transparent hybrid film with improved mechanical performance while maintaining it.

Republic of Korea Patent Registration No. 10-2037699 Republic of Korea Patent Publication No. 10-2020-0083284

An object of the present invention is to provide a transparent hybrid film containing fumed silica nanoparticles and a manufacturing method thereof.

In order to achieve the above purpose,

In one aspect of the invention

A fluorine-based polyamide-imide polymer in which a unit structure derived from a diamine compound, a unit structure derived from a dianhydride compound, and a unit structure derived from TPC (Terephthaloyl chloride; 1,4-benzenedicarbonyl chloride) are copolymerized; and

Including; fumed silica nanoparticles,

The fumed silica nanoparticles are included in an amount of 1 to 5 parts by weight based on the total weight of the solid content of the polyamide-imide polymer.

In another aspect of the present invention

preparing a fluorine-based polyamide-imide polymer;

preparing a mixed solution containing fumed silica nanoparticles in the fluorine-based polyamide-imide polymer; and

Including; preparing a film by casting the mixed solution;

The fumed silica nanoparticles are included in an amount of 1 to 5 parts by weight based on the total weight of the solid content of the fluorine-based polyamide-imide polymer.

In the transparent hybrid film provided in one aspect of the present invention, by adding fumed silica nanoparticles to a fluorine-based polyamide-imide polymer, a film with improved hardness, elastic modulus and tensile strength can be formed while maintaining transparency.

1 is a graph showing gel permeation chromatography (GPC) results of fluorine-based polyamide-imide polymerized according to a preparation example of the present invention.
2 is a graph showing UV-Vis transmission spectra of hybrid films according to an embodiment and a comparative example of the present invention.
3 is a graph showing UV-Vis transmission spectra of hybrid films according to an embodiment and a comparative example of the present invention.
4 shows photographs of hybrid films according to an embodiment of the present invention and a comparative example.

The present invention can apply various changes and thus various embodiments can come out, specific embodiments will be presented at the bottom and described in detail.

In addition, all terms in this specification that are not specifically defined will be able to be used in a meaning that can be understood by all those with ordinary knowledge in the technical field to which the present invention belongs.

However, it should be understood that the present invention is not limited to the specific embodiments described below, and includes all modifications, equivalents, and substitutes included in the spirit and technical scope of the present invention.

Therefore, there may be other equivalents and modifications to the embodiments described in this specification, and the embodiments presented in this specification are only the most preferred embodiments.

Hereinafter, the present invention will be described in detail.

In one aspect of the invention

A fluorine-based polyamide-imide polymer in which a unit structure derived from a diamine compound, a unit structure derived from a dianhydride compound, and a unit structure derived from TPC (Terephthaloyl chloride; 1,4-benzenedicarbonyl chloride) are copolymerized; and

Including; fumed silica nanoparticles,

The fumed silica nanoparticles are included in an amount of 1 to 5 parts by weight based on the total weight of the solid content of the polyamide-imide polymer.

Hereinafter, the transparent hybrid film provided in one aspect of the present invention will be described in detail for each material.

First, the transparent hybrid film provided in one aspect of the present invention has a unit structure derived from a diamine compound, a unit structure derived from a dianhydride compound, and a unit structure derived from TPC (Terephthaloyl chloride; 1,4-benzenedicarbonyl chloride). and copolymerized fluorine-based polyamide-imide polymers.

The fluorine-based polyamide-imide may be formed through polymerization of a diamine compound, a dianhydride compound, and dicarboxyl chloride (TPC).

At least one of the diamine compound and the dianhydride compound may contain a fluorine atom.

The fluorine-based polyamide-imide can produce a transparent film by suppressing charge transfer complex (CTC) between molecular chains by fluorine atoms. Natural dispersion of the fumed silica nanoparticles can be induced through hydrogen bonds between fluorine atoms included in the fluorine-based polyamide-imide of the present invention and hydroxyl groups of the fumed silica nanoparticles.

Diamine compounds that can be used in the polymerization of the fluorine-based polyamide-imide include, but are not limited to, 2,2'-bis(trifluoromethyl)benzidine (TFDB), 3,5-diaminobenzotrifluoride, 3,3'-(Hexafluoroisopropylidene)dianiline, 4,4'- (Hexafluoroisopropylidene)dianiline (4,4'-(Hexafluoroisopropylidene)dianiline), 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane (2,2-Bis(3-amino -4-methylphenyl)hexafluoropropane), 2,2-bis [4- (4-aminophenoxy) phenyl] hexafluoropropane (2,2-Bis [4- (4-aminophenoxy) phenyl] hexafluoropropane), 2, 2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (2,2-Bis(3-amino-4-hydroxyphenyl)hexafluoropropane, BAFA), 1,4-bis(4-amino-2- Trifluoromethylphenoxy) benzene (1,4-Bis (4-amino-2-trifluoromethylphenoxy) benzene), 4,4'-oxy-bis [3- (trifluoromethyl) benzeneamine] (4,4 It may be one or more selected from the group consisting of '-oxybis[3-(trifluoromethyl)benzenamine]) and mixtures thereof.

The dianhydride compound that can be used in the polymerization reaction is a non-limiting example, 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 6FDA), N,N '-(2,2'-bis(trifluoromethyl)biphenyl-4,4'-diyl)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxamide) (N,N'-(2,2'-bis(trifluoromethyl)biphenyl-4,4'-diyl)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxamide), TATFMB), 2,2 '-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'diyl bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate) (2,2'-bis(trifluoromethyl)-[1,1'-biphenyl]-4,4'-diyl bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate), TA-TFBP), 2,2'-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride (2,2-bis(trifluoromethyl)-4,4',5,5 '-biphenyltetracarboxylic dianhydride, 6FBPDA) and at least one selected from the group consisting of mixtures thereof.

The diamine compound and the dianhydride compound may be included in a molar ratio of 1:0.35 to 1:0.65.

In this case, the molar ratio of the diamine compound, the dianhydride compound, and the TPC may be preferably 1:1 (diamine compound: dianhydride compound and TPC).

The transparent hybrid film provided in one aspect of the present invention includes fumed silica nanoparticles.

Fumed silica is produced by a dry method, and refers to silica (SiO ₂ ) obtained by heating and decomposing silicon tetrachloride (SiCl ₄ ) in air. Fumed silica is generally characterized by a large surface area and fine particles.

The fumed silica nanoparticles are included in an amount of 1 to 5 parts by weight, preferably in an amount of 1 to 4.5 parts by weight, and more preferably in an amount of 1.5 to 4.5 parts by weight based on the total weight of the solid content of the polyamide-imide polymer. It may be included, more preferably 2 to 4 parts by weight.

When the fumed silica nanoparticles are included in less than 1 part by weight based on the solid content of the polyamide-imide polymer, the improvement in surface hardness of the hybrid film is insignificant, and when included in more than 5 parts by weight, physical properties of the hybrid film There is a problem with this rapid deterioration.

The fumed silica nanoparticles may have an average diameter of 5 to 300 nm, preferably 50 to 300 nm, and more preferably 85 to 270 nm. In one embodiment, the fumed silica nanoparticles may have an average diameter of 151 nm.

The diamine compound and the dianhydride compound may be included in a molar ratio of 1:0.55 to 1:0.65, and the fumed silica nanoparticles may be included in an amount of 1 to 4.5 parts by weight based on the total solid weight of the polyamide-imide polymer, It may preferably be included in 1.5 to 4.5 parts by weight, more preferably 2 to 4 parts by weight.

In this case, the molar ratio of the diamine compound, the dianhydride compound, and the TPC may be preferably 1:1 (diamine compound: dianhydride compound and TPC).

The diamine compound and the dianhydride compound may be included in a molar ratio of 1:0.45 to 1:0.55, and the fumed silica nanoparticles may be included in an amount of 1 to 3.5 parts by weight based on the total solid weight of the polyamide-imide polymer, It may preferably be included in 1.5 to 3.5 parts by weight, more preferably 2 to 3 parts by weight.

In this case, the molar ratio of the diamine compound, the dianhydride compound, and the TPC may be preferably 1:1 (diamine compound: dianhydride compound and TPC).

The diamine compound and the dianhydride compound may be included in a molar ratio of 1:035 to 1:0.45, and the fumed silica nanoparticles may be included in an amount of 1 to 2.5 parts by weight based on the total solid weight of the polyamide-imide polymer, It may preferably be included in 1.5 to 2.5 parts by weight, more preferably 1.7 to 2.2 parts by weight.

In this case, the molar ratio of the diamine compound, the dianhydride compound, and the TPC may be preferably 1:1 (diamine compound: dianhydride compound and TPC).

The pencil hardness of the transparent hybrid film provided in one aspect of the present invention may be 4H or more.

In addition, the transparent hybrid film provided in another aspect of the present invention may have a light transmittance of 76% or more at a wavelength of 450 nm.

In one embodiment, a transparent hard coating layer may be further formed on the transparent hybrid film including fumed silica nanoparticles.

In one embodiment, the transparent hard coating film may include a ladder-shaped ring epoxy polysilsesquioxane.

In the transparent hybrid film provided in one aspect of the present invention, by adding fumed silica nanoparticles to a fluorine-based polyamide-imide polymer, a film with improved hardness, elastic modulus and tensile strength can be formed while maintaining transparency.

Another aspect of the present invention is

preparing a fluorine-based polyamide-imide polymer;

preparing a mixed solution containing fumed silica nanoparticles in the fluorine-based polyamide-imide polymer; and

Including; preparing a film by casting the mixed solution;

The fumed silica nanoparticles are included in an amount of 1 to 5 parts by weight based on the total weight of the solid content of the fluorine-based polyamide-imide polymer.

The step of preparing the fluorine-based polyamide-imide polymer is

A first polymerization step of solution-reacting a diamine compound and a dianhydride compound, and a second polymerization step of solution-reacting a polymer obtained through the first polymerization step and TPC (Terephthaloyl chloride; 1,4-benzenedicarbonyl chloride), A polyamic acid production process for preparing a mix acid solution; and an imidization step of subjecting the polyamic acid solution prepared by the polyamic acid preparation step to a chemical imidization reaction in the presence of an imidation catalyst. can include

The fumed silica nanoparticles are included in an amount of 1 to 5 parts by weight based on the total solid weight of the polyamide-imide polymer. Preferably, it may be included in 1 to 4.5 parts by weight, more preferably 1.5 to 4.5 parts by weight, and more preferably 2 to 4 parts by weight. When the fumed silica nanoparticles are included in less than 1 part by weight based on the solid content of the polyamide-imide polymer, the improvement in surface hardness of the hybrid film is insignificant, and when included in more than 5 parts by weight, physical properties of the hybrid film There is a problem with this rapid deterioration.

In the transparent hybrid film provided in one aspect of the present invention, by adding fumed silica nanoparticles to a fluorine-based polyamide-imide polymer, a film with improved hardness, elastic modulus and tensile strength can be formed while maintaining transparency.

Hereinafter, the present invention will be described in detail through Examples and Experimental Examples.

However, the Examples and Experimental Examples to be described below are only to specifically illustrate the present invention in one aspect, but the present invention is not limited thereto.

<Preparation Example 1> Polymerization of fluorine-based polyamide-imide (PAI-4)

Polymerization of fluorine-based polyamide-imide is shown in Scheme 1 below.

<Scheme 1>

Polymerization was carried out in a glove box in which the relative humidity was lowered to 15% or less through nitrogen substitution. After creating a nitrogen atmosphere by passing nitrogen through a 1L double jacket reactor equipped with a stirrer and a stir bar, 23.00 g (0.0718 mol) of TFDB as a diamine compound and 553.93 g of DMAc as a solvent were added and sufficiently stirred until TFDB was completely dissolved. At this time, the temperature of the reaction vessel was maintained at 25° C. using a temperature control fluid circulation device. Here, 19.34 g (0.0435 mol) of 6FDA, a dianhydride (dianhydride) compound having a molar ratio smaller than that of TFDB, was added thereto, followed by stirring for a certain period of time to synthesize a polyamic acid oligomer having amine groups at both ends.

Thereafter, a chain extension reaction was performed by adding 5.83 g (0.0287 mol) of TPC to obtain a high molecular weight polyamide-amic acid solution.

8.61 g of pyridine and 11.11 g of acetic anhydride were added to the polyamide-amic acid solution as a catalyst and dehydrating agent for chemical imidation reaction, stirred at room temperature for 30 minutes, then raised to 80° C., stirred for 1 hour, and then returned to room temperature. cooled down Thereafter, it was slowly dropped into 2 L of methanol to precipitate, and the precipitated solid was collected by filtration and washed repeatedly with excess methanol three times. The finally obtained solid content was dried in a vacuum oven at 80° C. for 10 hours to obtain 43.12 g of solid polyamide-imide polymer (PAI-4).

<Preparation Example 2> Polymerization of fluorine-based polyamide-imide (PAI-5)

In Preparation Example 1, 23.00 g (0.0718 mol) of TFDB as an imide compound and 533.64 g of DMAc as a solvent were added and sufficiently stirred until TFDB was completely dissolved. Here, 16.11 g (0.0363 mol) of 6FDA, a dianhydride compound having a molar ratio smaller than that of TFDB, was added thereto, followed by stirring for a certain period of time to synthesize polyamic acid oligomers having amine groups at both ends.

Thereafter, a chain extension reaction was performed by adding 7.29 g (0.0359 mol) of TPC to obtain a high molecular weight polyamide-amic acid solution.

The chemical imidation reaction of the polyamide-amic acid solution and the recovery of the solid content were carried out in the same manner as in Preparation Example 1. Finally, 41.16 g of solid polyamide-imide polymer (PAI-5) was obtained.

<Production Example 3> Polymerization of fluorine-based polyamide-imide (PAI-6)

In Preparation Example 1, 23.00 g (0.0718 mol) of TFDB as an imide compound and 513.34 g of DMAc as a solvent were added and sufficiently stirred until TFDB was completely dissolved. Here, 12.89 g (0.0290 mol) of 6FDA, a dianhydride compound having a molar ratio smaller than that of TFDB, was added thereto, followed by stirring for a certain period of time to synthesize polyamic acid oligomers having amine groups at both ends.

Thereafter, a chain extension reaction was performed in which 8.75 g (0.0431 mol) of TPC was added to obtain a high molecular weight polyamide-amic acid solution.

The chemical imidation reaction of the polyamide-amic acid solution and the recovery of the solid content were carried out in the same manner as in Preparation Example 1. Finally, 39.20 g of solid polyamide-imide polymer (PAI-6) was obtained.

<Preparation Example 4> Polymerization of ladder-type cyclic epoxy polysilsesquioxane (LPESQ)

<Scheme 2>

4.80 g of distilled water and 0.04 g of potassium carbonate (K ₂ CO ₃ ) were added to a dried 100 ml round bottom flask, stirred for 10 minutes, and then 8.0 g of tetrahydrofuran was added dropwise and stirred at room temperature for 30 minutes. Then, 19.72 g of [2-(3,4-epoxycyclohexyl)ethyl]trimethoxysilane (ECMS), an epoxy silane monomer, was slowly added dropwise thereto at room temperature for 3 days. was stirred at. After the reaction was completed, the product was dissolved in methylene chloride (MC) and washed three times with distilled water, and the reactant dissolved in methylene chloride was recovered. LPESQ was recovered by removing water remaining in the reactant recovered using sodium sulfate (Na ₂ SO ₄ ) and evaporating the solvent. Polymerized LPESQ had a number average molecular weight of 5,510 g/mol and a molecular weight dispersion (PDI) of 1.42.

Measurement of molecular weight and molecular weight distribution

The molecular weight and molecular weight distribution of the polymerized PAI were measured by the following method. Polymerized PAI was dissolved in dimethylformamide (DMF) at a concentration of about 1%, filtered through a 0.45 μm PTFE syringe filter, and molecular weight and molecular weight distribution were measured by gel permeation chromatography (GPC, Young Lin SP930D solvent delivery pump) method. Specific GPC analysis conditions are as follows. Columns: Shodex GPC KD-806M (8.0mm l.D. x300mm) x2, Flow rate: 1.0 mL/min, Eluent: 0.01M LiBr in DMF.

<Examples 1 to 9> Hybrid films containing fumed silica nanoparticles

A hybrid film was prepared using the fluorine-based polyamide-imide polymer and the fumed silica nanoparticles synthesized in Preparation Examples 1 to 3.

The size of the fumed silica used is 85 to 270 nm in particle diameter, preferably 151 nm, and the specific surface area (BET) is 350 to 410 m ² /g.

The fumed silica was dried in a vacuum oven at 120° C. for more than 6 hours, added to 37.6 g of DMAc, and then dispersed using a sonicator. The content of the fumed silica was added after being adjusted to 2 to 5 parts by weight relative to the polyamide-imide (PAI) solid powder. After adding 3.27 g of PAI solid powder to the dispersed solution, the mixture was stirred for more than 12 hours using an overhead stirrer and a stirring rod.

After filtering out foreign substances such as dust or undissolved PAI from the obtained solution with a sus mesh, air bubbles in the solution were removed using a vacuum pump and a vacuum oven. Then, the solution was cast to ~290 μm using an applicator on a clean glass plate, and then dried in a hot air dryer at 90 ° C for 1 hour. Thereafter, it was placed in a vacuum oven and residual solvent was removed in a nitrogen atmosphere, and heat treatment was performed slowly at 200 ° C. for 1 hour and at 250 ° C. for 1 hour. After cooling, the dried film was put in distilled water to separate the film from the glass plate to finally obtain a polyamide-imide (PAI) hybrid film containing fumed silica nanoparticles.

<Examples 10 to 12> Hybrid film containing fumed silica nanoparticles having LPESQ coating film formed thereon

The LPESQ prepared in Preparation Example 4 was coated on the films of Examples 4 to 6 (PAI-5) to prepare a hybrid film having an LPESQ hard coating film.

The LPESQ of Preparation Example 4 was dissolved in a solvent of PGMEA (propylene glycol monomethyl ether acetate) at a concentration of 50% by weight. A cationic photoinitiator, THS (triarylsulfonium hexafluoroantimonate salts, mixed) was added at 4% by weight relative to the total mass of LPESQ to prepare a coating solution, and then bar coating was performed on the films of Examples 4 to 6 (PAI-5). The coated film was dried in a hood for 30 minutes and then dried in a vacuum oven at 60° C. for 30 minutes. Thereafter, irradiation was performed with an ultraviolet irradiator (10.26 J/cm ² ) for 45 seconds and heat treatment was performed in an oven at 150° C. for 1 hour to prepare a LPESQ-coated hybrid film.

<Comparative Examples 1 to 3> Polyamide-imide film

A highly transparent PAI film using the polyamide-imide (PAI) of Preparation Examples 1 to 3 was prepared.

<Comparative Example 4> Polyamide-imide film with LPESQ coating film

An LPESQ-coated PAI film was prepared in the same manner as in Example 10, except that LPESQ was coated on the polyamide-imide film of Comparative Example 2.

Experiments of Experimental Examples 1 to 6 were performed on Comparative Examples 1 to 4 and Examples 1 to 12. The results are shown in Tables 2 and 3 below.

<Experimental Example 1> Evaluation of pencil hardness

After inserting a pencil (Mitsubishi Co.) by hardness at a 45° angle in a manual pencil hardness tester according to ASTM D3363 and scratching the film 30 mm each 5 times while applying a 1Kg load, the highest hardness with no scratches when observed with the naked eye It was confirmed and made into pencil hardness.

<Experimental Example 2> Evaluation of water contact angle

After dropping water on the surface of the film or coated film at room temperature, the contact angle with the surface was measured using the ICMeasure 1.2 program. The contact angle was measured 5 times at random locations on the same sample, and the average value was used.

<Experimental Example 3> Evaluation of light transmittance

Visible light transmittance in the range of 300 nm to 800 nm of the film or coated film was measured using a UV-Vis spectrophotometer (Thermo scientific Co., Evolution201), and the results are shown in FIGS. 2 and 3 . Tables 2 and 3 show transmittance values for visible light at a wavelength of 450 nm.

<Experimental Example 4> Transparency evaluation

When the film or coated film was viewed with the naked eye, transparency was evaluated separately according to the degree of cloudiness.

O: Looks transparent to the naked eye without cloudiness

△: Visually, the coating is transparent, but a fine clouding phenomenon is seen.

X: The coating is opaque due to cloudiness, etc.

<Experimental Example 5> Evaluation of bending resistance

After winding the film or coated film (3cm x 10cm x 120㎛, PET film thickness: ~100㎛, coating film thickness: ~20㎛) on a cylindrical mandrel bending tester (cylindrical mandrel bending tester) and maintaining it for more than 5 seconds, When the bending tester was released, whether or not cracks occurred in the hard coating film was visually evaluated. Starting from the maximum cylinder radius of the mandrel bending tester, the diameter of the cylinder was gradually decreased and measured, and the minimum radius of the cylinder without cracks was determined as the bending radius. The bending radius was evaluated in the compression direction (in-folding direction) and the tensile direction (out-folding direction).

<Experimental Example 6> Evaluation of tensile strength

It was measured according to the standard of ASTM-D882 using a universal tensile tester. The size of the specimen was 20 mm x 160 mm, the load cell was 1 kN, and the tensile speed was 10.0 mm/min. Seven measurements per specimen were made, and the elastic modulus and tensile strength were determined as average values excluding the maximum and minimum values among the measured values.

The results of Experimental Examples 1 to 6 are shown in Tables 2 and 3 below.

According to Table 2 and FIG. 2,

The present invention is a hybrid film in which fumed silica nanoparticles are added in an amount of 1 to 5 parts by weight relative to the fluorine-based polyamide-imide polymer, and it is confirmed that the mechanical properties such as surface hardness, elastic modulus, and tensile strength are simultaneously improved while maintaining transparency. do.

Comparative Examples 1 to 3 in which fumed silica nanoparticles were not added had a surface hardness of 3H, but in Examples 1 to 9 in which fumed silica nanoparticles were added, the surface hardness was improved to 4H.

In addition, it was found that, by preparing a hybrid film in which fumed silica was added to polyamide-imide, the elasticity modulus and tensile strength were greatly increased while maintaining the transparency of the film.

More specifically, in the case of the polyamide-imide-based film of PAI-4 of Preparation Example 1, the films of Examples 1 and 2 including 1 to 4.5 parts by weight of fumed silica based on the polyamide-imide Compared to Comparative Example 2, the elastic modulus and tensile strength were improved while maintaining transparency.

In addition, in the case of the film using the polyamide-imide of PAI-5 of Preparation Example 2, the films of Examples 4 and 5 containing 1 to 3.5 parts by weight of fumed silica based on the polyamide-imide were compared to Comparative Example 2. Elastic modulus and tensile strength were improved while maintaining transparency.

In addition, in the case of the film using the polyamide-imide of PAI-6 of Preparation Example 3, the film of Example 7 containing 1 to 2.5 parts by weight of fumed silica relative to the polyamide-imide has transparency compared to Comparative Example 3 It was found that the modulus of elasticity and tensile strength were improved while maintaining it.

Referring to FIG. 3 and Table 3, when a hard coating film using LPESQ is formed on the surface of the hybrid film to which fumed silica nanoparticles are added, the surface while maintaining transparency compared to the polyamide-imide film without fumed silica nanoparticles added. It was confirmed that the hardness was improved more excellently.

More specifically, the surface hardness of Comparative Example 4 was 6H, whereas the surface hardness of Examples 10 to 13 was 8H. That is, it can be seen that the effect of the hard coating can be further increased by increasing the surface hardness of the substrate itself to be hard coated.

The water contact angle of the polyamide-imide film in Table 2 decreases as the amount of fumed silica nanoparticles added increases, which means that the added fumed silica nanoparticles move to the film surface during the drying process of the polyamide-imide film do. The silica nanoparticles protruding on the surface can provide a hydroxy group, which is a chemical reactive group, so that they can chemically bond with the reactive hard coating composition to be coated.

In addition, as shown in Table 3, the bending radius in the tensile direction decreases as the amount of silica added increases. As the amount of silica nanoparticles derived to the surface increases, the chemistry between the silica nanoparticles derived from the film surface and the coated LPESQ It can be seen that the reaction occurs and mutually strengthened chemical bonds are formed, so that the hard coating film is not detached during bending.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art can implement the present invention in other specific forms without changing its technical spirit or essential features. You will understand that there is Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (12)

A fluorine-based polyamide-imide polymer in which a unit structure derived from a diamine compound, a unit structure derived from a dianhydride compound, and a unit structure derived from TPC (Terephthaloyl chloride; 1,4-benzenedicarbonyl chloride) are copolymerized; and
Including; fumed silica nanoparticles,
The fumed silica nanoparticles are included in 1 to 5 parts by weight based on the total weight of the solid content of the polyamide-imide polymer, the transparent hybrid film.
According to claim 1,
The size of the fumed silica nanoparticles is an average particle diameter of 5 to 300 nm, the transparent hybrid film.
According to claim 1,
At least one of the diamine compound and the dianhydride compound contains a fluorine atom, a transparent hybrid film.
According to claim 1,
The diamine compound is 2,2'-bis (trifluoromethyl) benzidine (2,2'-Bis (trifluoromethyl) benzidine, TFDB), 3,5-diaminobenzotrifluoride (3,5-Diaminobenzotrifluoride), 3,3'-(hexafluoroisopropylidene)dianiline (3,3'-(Hexafluoroisopropylidene)dianiline), 4,4'-(hexafluoroisopropylidene)dianiline (4,4'-(Hexafluoroisopropylidene) )dianiline), 2,2-bis (3-amino-4-methylphenyl) hexafluoropropane (2,2-Bis (3-amino-4-methylphenyl) hexafluoropropane), 2,2-bis [4- (4 -Aminophenoxy)phenyl]hexafluoropropane (2,2-Bis[4-(4-aminophenoxy)phenyl]hexafluoropropane), 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (2,2-Bis(3-amino-4-hydroxyphenyl)hexafluoropropane, BAFA), 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene (1,4-Bis(4-amino -2-trifluoromethylphenoxy)benzene), 4,4'-oxy-bis[3-(trifluoromethyl)benzenamine](4,4'-oxybis[3-(trifluoromethyl)benzenamine]) and mixtures thereof A transparent hybrid film that is one or more selected from the group to be.
According to claim 1,
The dianhydride compound is 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (4,4'-(hexafluoroisopropylidene)diphthalic anhydride, 6FDA), N,N'-(2,2'-bis(tri) Fluoromethyl)biphenyl-4,4'-diyl)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxamide)(N,N'-(2,2'-bis(trifluoromethyl)biphenyl-4,4'-diyl)bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxamide), TATFMB), 2,2'-bis(trifluoromethyl)-[ 1,1'-biphenyl] -4,4' diyl bis (1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate) (2,2'-bis (trifluoromethyl) - [1,1'-biphenyl]-4,4'-diyl bis(1,3-dioxo-1,3-dihydroisobenzofuran-5-carboxylate), TA-TFBP), 2,2'-bis(trifluoromethyl )-4,4',5,5'-biphenyltetracarboxylic dianhydride (2,2-bis(trifluoromethyl)-4,4',5,5'-biphenyltetracarboxylic dianhydride, 6FBPDA) and mixtures thereof At least one selected from the group consisting of, a transparent hybrid film.
According to claim 1,
The diamine compound and the dianhydride compound are included in a molar ratio of 1: 0.35 to 1: 0.65, the transparent hybrid film.
According to claim 1,
The diamine compound and the dianhydride compound are included in a molar ratio of 1:0.55 to 1:0.65, and the fumed silica nanoparticles are included in 1 to 4.5 parts by weight based on the total weight of the solid content of the polyamide-imide polymer. , a transparent hybrid film.
According to claim 1,
The diamine compound and the dianhydride compound are included in a molar ratio of 1:0.45 to 1:0.55, and the fumed silica nanoparticles are included in 1 to 3.5 parts by weight based on the total weight of the solid content of the polyamide-imide polymer. , a transparent hybrid film.
According to claim 1,
The diamine compound and the dianhydride compound are included in a molar ratio of 1:0.35 to 1:0.45, and the fumed silica nanoparticles are included in 1 to 2.5 parts by weight based on the total weight of the solid content of the polyamide-imide polymer. , a transparent hybrid film.
According to claim 1,
The pencil hardness of the transparent hybrid film is 4H or more, the transparent hybrid film.
According to claim 1,
The transparent hybrid film has a light transmittance of 450 nm wavelength of 76% or more, a transparent hybrid film.
preparing a fluorine-based polyamide-imide polymer;
preparing a mixed solution containing fumed silica nanoparticles in the fluorine-based polyamide-imide polymer; and
Including; preparing a film by casting the mixed solution;
Wherein the fumed silica nanoparticles are included in an amount of 1 to 5 parts by weight based on the total weight of the solid content of the fluorine-based polyamide-imide polymer.

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