KR20170136278A - High strength transparent polyamide-imide and process for preparing same - Google Patents

Abstract

The present invention provides a polyamideimide film which maintains transparency and has greatly improved mechanical properties and heat resistance. Polyamideimide of the present invention includes a repeating structure represented by chemical formula 1a together with a repeating structure represented by chemical formula 1b, wherein the repeating structure of chemical formula 1a and the repeating structure of chemical formula 1b are polymerized at a molar ratio of 2:8 to 7:3. The polyamideimide is excellent in transparency, heat resistance, mechanical strength and flexibility. Therefore, the polyamideimide can be used in various fields including a substrate for elements, a cover substrate for displays, an optical film, an integrated circuit (IC) package, an adhesive film, a multilayer flexible printed circuit (FPC), a tape, a touch panel, a protective film for optical disks, and the like.

Description

TECHNICAL FIELD [0001] The present invention relates to a high-strength transparent polyamideimide and a method for producing the same. BACKGROUND ART [0002]

The present invention relates to a polyamideimide which exhibits colorless, transparent and high strength mechanical properties, and a process for producing the same.

Polyimide (PI) is a polymer having a relatively low crystallinity or mostly noncrystalline structure. It is easy to synthesize and can produce a thin film film. It also has advantages of not requiring a crosslinking agent for curing, transparency, rigid chain structure Is a polymer material with excellent heat resistance, chemical resistance, excellent mechanical properties, electrical properties and dimensional stability. It is widely used in electric and electronic materials such as automobile, aerospace, flexible circuit board, liquid crystal alignment film for LCD, have

Although polyimide is a high-performance polymer material having high thermal stability, mechanical properties, chemical resistance, and electrical properties, it does not satisfy the basic requirement for use in the display field, which is a colorless transparent property, . For example, the coefficient of thermal expansion of Kapton sold by DuPont has a thermal expansion coefficient as low as about 30 ppm / ° C, but this is still below the requirements of plastic substrates. Therefore, many researches have been carried out to minimize changes in optical characteristics and thermal history while maintaining the basic characteristics of polyimide.

In general, the aromatic polyimide has a distinctive dark brown color because the π electrons of benzene present in the imide main chain have a charge transfer complex (CT-complex ). This is because electrons can be excited because σ electrons, π electrons, and nonbonding non-covalent electron pairs exist in the imide structure.

In the case of a general polyimide, the color of yellow to red, which is a color of its color, becomes visible as it absorbs light in a visible light range from a wavelength of 400 nm or less to 500 nm. Therefore, in order to lower the CT-complex, which is a disadvantage of the aromatic polyimide, an element having relatively high electronegativity such as trifluoromethyl (-CF ₃ ), sulfone (-SO ₂ ), and ether (-O-) There is a method of reducing the resonance effect by restricting the movement of the π electrons. By introducing an olefinic cycloolefin structure other than benzene, the density of π electrons present in the main chain is reduced to produce a colorless transparent polyimide film .

On the other hand, polyamideimide has been widely used as an industrial material for electric, electronic, mechanical, aviation, and the like since it has excellent heat resistance, mechanical strength and electrical characteristics. It is also known that polyamide imides are soluble in organic solvents, and they are also used for enamel varnishes, coatings for electrical insulation, coatings for paints, and other applications where solution molding is indispensable .

However, for use in the display field, it is necessary to develop a polymer for a flexible display having a lower coefficient of thermal expansion, high solubility, transparency and thermal stability.

A problem to be solved by the present invention is to provide a polyamideimide having improved transparency and mechanical strength.

Another object to be solved by the present invention is to provide a process for producing the polyamideimide.

Another object of the present invention is to provide a high strength transparent polyamide imide film made of the above polyamideimide.

In order to solve the above-described technical problem,

A polyamideimide comprising a repeating structure represented by the following formula (1a) and a repeating structure represented by the formula (1b), wherein the repeating structure of the formula (1a) and the repeating structure of the formula (1b) are polymerized in a molar ratio of 2: 8 to 7: to provide.

[Formula 1a]

[Chemical Formula 1b]

In the above general formulas (1a) and (1b)

X ₁ is a tetravalent organic group derived from a tetracarboxylic dianhydride represented by the following formula (2)

(2)

X ₂ is a divalent organic group derived from a compound represented by the following formula (3)

(3)

In the above formula,

Z is one selected from a hydroxyl group (-OH), a halide group selected from -Cl, -Br, -F, -I and an alkoxy group having 1 to 5 carbon atoms (-OR)

Y ₁ and Y ₂ are divalent organic groups derived from a diamine, at least one of which contains a divalent organic group of the following formula

[Chemical Formula 4]

In Formula 4,

R ₁ and R ₂ each independently represent a halogen atom, -OH, -OH, -SH, nitro, -NH ₂ , An alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms,

Q is a single _{bond, -O-, -CR 18 R 19 -} , -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , A phenylene group and a combination thereof, wherein each of R ₁₈ and R ₁₉ is independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Is selected.

The present invention also provides a method for producing the polyamideimide.

In order to solve the other problems of the present invention, there is provided a polyamideimide film comprising the polyamideimide.

The present invention provides a polyamideimide film having improved mechanical properties and heat resistance while maintaining transparency. The polyamide imide is excellent in transparency, heat resistance, mechanical strength and flexibility and can be used as a substrate for a device, a cover substrate for a display, an optical film, an IC (integrated circuit) package, an adhesive film, a multilayer FRC ), Tapes, touch panels, protective films for optical discs, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS The present invention is capable of various modifications and various embodiments, and specific embodiments are illustrated in the drawings and described in detail in the detailed description. It is to be understood, however, that the invention is not to be limited to the specific embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

In the present specification, all the compounds or organic groups may be substituted or unsubstituted, unless otherwise specified. Herein, the term "substituted" means that at least one hydrogen contained in the compound or organic group is substituted with a halogen atom, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, a cycloalkyl group having 3 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, Substituted with a substituent selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, a carboxylic acid group, an aldehyde group, an epoxy group, a cyano group, a nitro group, an amino group, a sulfonic acid group and derivatives thereof.

In the present specification, "a combination thereof" means a compound wherein at least two functional groups are a single bond, a double bond, a triple bond, an alkylene group having 1 to 10 carbon atoms (for example, a methylene group (-CH ₂ -), Ethylene group (-CH ₂ CH ₂ -), etc.), a fluoroalkylene group having 1 to 10 carbon atoms (for example, a fluoromethylene group (-CF ₂ -), a perfluoroethylene group (-CF ₂ CF ₂ -, etc.), a hetero atom such as N, O, P, S, or Si, or a functional group containing it (e.g., a carbonyl group in the molecule (-C═O-), an ether group (-O-) Or a heteroalkylene group containing a heteroatom (-COO-), -S-, -NH- or -N = N-, etc.), or two or more functional groups are condensed and connected.

Polyimide is composed of rigid aromatic rings and imide bonds and shows excellent mechanical properties and heat resistance. Based on these characteristics, polyimide is used in various forms in many industrial fields. However, the conventional polyimide absorbs a part of visible light due to electron transfer between chains and chains, and may exhibit yellowing, which may hinder the possibility of a high heat-resistant transparent material for displays. This yellowing may be caused by charge transfer complexity, which may be more pronounced as the packing of the rigid polyimide polymer chains becomes more pronounced.

In order to solve such a conventional problem,

The polyamide-imide according to the present invention is a polyamide-

The present invention provides a polyamideimide which is polymerized at a molar ratio of 2: 8 to 7: 3, including a repeating structure represented by the following formula (1a) and a repeating structure represented by the formula (1b).

[Formula 1a]

[Chemical Formula 1b]

In the above general formulas (1a) and (1b)

X ₁ is a tetravalent organic group represented by the following formula (2) derived from a tetracarboxylic dianhydride,

(2)

X ₂ is a divalent organic group derived from a compound represented by the following formula (3)

(3)

In Formula 3,

Z is one selected from a hydroxyl group (-OH), a halide group selected from -Cl, -Br, -F, -I and an alkoxy group having 1 to 5 carbon atoms (-OR)

Y &_lt; ₁ > and Y &_lt; _{2 >} are divalent organic groups derived from a diamine, at least one of which contains the structure of formula (4)

[Chemical Formula 4]

In Formula 4,

Each of R ₁ and R ₂ independently represents a halogen atom consisting of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group (-SH), a nitro group (-NO ₂ ) An alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms, preferably a halogen atom, a halogenoalkyl group , An alkyl group, an aryl group, and a cyano group. For example, the halogen atom may be fluoro (-F), and the halogenoalkyl group may be a fluoroalkyl group having 1 to 10 carbon atoms including a fluoro group, such as a fluoromethyl group, a perfluoroethyl group, And the alkyl group may be selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, a pentyl group and a hexyl group, and the aryl group may be selected from a phenyl group and a naphthalenyl group And more preferably a substituent group including a fluorine atom such as a fluorine atom and a fluoroalkyl group.

Q is a single _{bond, -O-, -CR 18 R 19 -} , -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , A phenylene group and a combination thereof, wherein each of R ₁₈ and R ₁₉ is independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Is selected.

The present invention can introduce a polyamide into the polyimide main chain. Like the polyimide, the polyimide has excellent mechanical properties and heat resistance. When copolymerized with polyimide, it blocks packing between chains of the polymer and lower the charge transfer, The characteristics can be improved.

According to one embodiment, the hydrogen of the aromatic ring included in Formula 2 may be a halogen atom of -F, -Cl, -Br and -I, a hydroxyl group (-OH), a thiol group (-SH) (-NO ₂ ), a cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 20 carbon atoms . For example, the halogen atom may be fluoro (-F), and the halogenoalkyl group may be a fluoroalkyl group having 1 to 10 carbon atoms including a fluoro group, such as a fluoromethyl group, a perfluoroethyl group, And the alkyl group may be selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, a pentyl group and a hexyl group, and the aryl group may be selected from a phenyl group and a naphthalenyl group And more preferably a substituent group including a fluoro group such as a fluoro atom and a fluoroalkyl group.

According to one embodiment, the formula (2) may be selected from tetracarboxylic acid dianhydrides having the structures of the following formulas (2a) to (2b).

The hydrogen of the aromatic ring included in Formula 2 may be substituted with a halogen atom, -OH, -OH, -SH, nitro, -NO ₂ , -F, -Cl, -Br, A cyano group, an alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms. For example, the halogen atom may be fluoro (-F), and the halogenoalkyl group is a fluoroalkyl group having 1 to 10 carbon atoms including a fluoro atom, and examples thereof include a fluoromethyl group, a perfluoroethyl group, And the alkyl group may be selected from a methyl group, an ethyl group, a propyl group, an isopropyl group, a t-butyl group, a pentyl group and a hexyl group, and the aryl group may be selected from a phenyl group and a naphthalenyl group And more preferably a substituent group including a fluorine atom such as a fluorine atom and a fluoroalkyl group.

According to one embodiment, Formula 3 may be a dicarboxylic dichloride of Formula 3a or a dicarboxylic acid of Formula 3b.

[Chemical Formula 3]

(3b)

In addition,

Comprising the steps of: stirring a diamine comprising a structure of Formula 4;

A tetracarboxylic dianhydride having a tetravalent organic group represented by the following formula (2) and a compound represented by the following formula (3) are added to the diamine solution in a molar ratio of 2: 8 to 7: 3 at a molar ratio of 2: 8 to 7: 3 to prepare a polyamideimide precursor step; And

And imidizing the polyamideimide precursor. The present invention also provides a process for producing a polyamideimide comprising the steps of:

 (2)

(3)

In Formula 3,

Z is one selected from the group consisting of a hydroxyl group (-OH), a halide group (-Cl, -Br, -F, -I), and an alkoxy group having 1 to 5 carbon atoms (-OR)

[Chemical Formula 4]

In Formula 4,

R ₁ and R ₂ each independently represent a halogen atom, -OH, -OH, -SH, nitro, -NH ₂ , An alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy group having 1 to 4 carbon atoms, a halogenoalkyl group having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms.

Q is a single _{bond, -O-, -CR 18 R 19 -} , -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , A phenylene group and a combination thereof, wherein each of R ₁₈ and R ₁₉ is independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Is selected.

For example, the compound of formula (4) may be selected from the compounds of the following formulas (4a) to (4d).

The polyamideimide precursor includes a repeating structure of the following formulas (5a) and (5b), and the repeating structure of the following formula (5a) may be imidized to form a polyamideimide repeating structure of formula (1a).

[Chemical Formula 5a]

[Chemical Formula 5b]

According to one embodiment, the imidization ratio of the structure including the above-mentioned formula (Ia) may be 80 to 100%, preferably imidized at an imidization rate of 90 to 100%.

In the above general formulas (1a) to (1b)

According to the present invention, the repeating structure of Formula 1a and the repeating structure of Formula 1b may be polymerized in a molar ratio of 2: 8 to 8: 2, preferably in a molar ratio of 2: 8 to 5: 5, May contain an excess of the repeating structure of formula (Ib) in excess of formula (1a), and may be polymerized in a molar ratio of, for example, 1: 5 to 1: 1.1.

That is, the tetracarboxylic acid dianhydride having the tetravalent organic group of Formula 2 and the compound of Formula 3 may be polymerized in a molar ratio of 2: 8 to 8: 2, preferably 2: 8 to 5: 5, more preferably in a molar ratio of 1: 5 to 1: 1.1, and reacted with the diamine of Formula 4 to prepare a polyamideimide precursor.

At this time, when the compound of Formula 3 is reacted in an amount of 90 mol% or more, preferably 80 mol% or more, the viscosity of the polymerization solution is increased by gelation, And the film produced therefrom may have low uniformity and may affect optical properties such as transparency. When the tetracarboxylic dianhydride is contained in an amount of 90 mol% or more, preferably 80 mol% or more, or more than 70 mol%, the chain of the precursor is decomposed by the structure of polyamic acid which is vulnerable to moisture Which may deteriorate the mechanical properties of the film.

According to one embodiment, the polyamideimide according to the present invention is a random copolymer, which may be in a randomly arranged configuration of repeating structures, which prevents intra-chain charge transfer and inhibits regular arrangement, It is possible to minimize the occurrence of partial crystallization by inter-chain hydrogen bonding of the polyamide-imide film of the present invention.

The present invention not only exhibits excellent heat resistance and mechanical properties by introducing a polyamide group into a conventional polyimide structure but also can prevent complexity of charge transfer due to packing phenomenon due to an increase in the distance between chains due to polyamide groups, , It is possible to provide a more colorless transparent polyamideimide while maintaining high heat resistance and mechanical properties.

In addition, the present invention can prevent the inter-chain packing due to the size of the substituent by introducing a substituent having a high electronegativity, such as R ₁ and R ₂ , into the diamine structure, , The charge transfer can be minimized, and thus the polyamideimide can be provided, in which the optical properties such as the yellow transition that can be caused by such charge transfer are significantly improved.

For example, the polyamide imide according to the present invention may include a repeating structure represented by the following general formulas (1a-1) and (1b-1).

[Formula 1a-1]

[Chemical Formula 1b-1]

According to one embodiment, the polyamideimide according to the present invention can be prepared by further adding a tetracarboxylic acid dianhydride represented by the following formula (6).

[Chemical Formula 6]

In Formula (6), X ₃ is an alicyclic or tetravalent organic group containing two or more aromatic rings.

For example, X ₃ may be a tetravalent organic group containing an aliphatic ring having 3 to 24 carbon atoms or an aromatic ring having 6 to 30 carbon atoms, for example, a tetravalent organic group represented by the following general formulas (8a) to (8h) More preferably, the aromatic ring or aliphatic structure is a structure in which each ring structure is rigid, that is, a structure in which each ring is bonded in a single bond, or a structure in which each ring is directly connected May be a tetravalent organic group including a recited structure.

At least one hydrogen atom in the tetravalent organic group of the general formulas (8a) to (8h) is an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, A fluoroalkyl group having 1 to 10 carbon atoms (e.g., a fluoromethyl group, a perfluoroethyl group or a trifluoromethyl group), an aryl group having 6 to 12 carbon atoms (e.g., a phenyl group, a naphthalenyl group, etc.) A sulfonic acid group, and a carboxylic acid group, and may be substituted with a fluoroalkyl group having preferably 1 to 10 carbon atoms.

In the polyamideimide according to the present invention, Y ₁ and Y ₂ may be the same or different, and at least one of Y ₁ and Y ₂ is derived from a diamine containing the structure of formula (4).

According to one embodiment, in addition to the divalent organic group represented by the formula (4), an aliphatic, alicyclic or aromatic divalent organic group having 12 to 30 carbon atoms or an aromatic divalent organic group having 12 to 30 carbon atoms, Or aromatic divalent organic groups are directly connected to each other, or are selected from divalent organic groups connected to each other through a crosslinking structure. For example, a monocyclic or polycyclic aromatic group having 12 to 30 carbon atoms, a monocyclic or polycyclic alicyclic group having 12 to 30 carbon atoms, or a structure in which two or more thereof are linked by a single bond, 7i < / RTI > divalent organic group.

At least one hydrogen atom in the divalent organic group of formulas (7a) to (7i) is an alkyl group having 1 to 10 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, t- butyl, pentyl, A fluoroalkyl group having 1 to 10 carbon atoms (e.g., a fluoromethyl group, a perfluoroethyl group or a trifluoromethyl group), an aryl group having 6 to 12 carbon atoms (e.g., a phenyl group, a naphthalenyl group, etc.) A sulfonic acid group, and a carboxylic acid group, and may be substituted with a fluoroalkyl group having preferably 1 to 10 carbon atoms.

In the repeating structure of the polyamideimide precursor of the present invention, one or more repeating structures may contain a divalent organic group and / or a tetravalent organic group containing a fluoro-based substituent. Here, the term "fluoro group substituent" means not only a "fluoro atom substituent" but also a "substituent group containing a fluoro atom". The fluorine-based substituent may be a fluoroalkyl group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, and may be at least 30 mol%, preferably at least 40 mol%, based on the repeating structure of the entire polyamideimide precursor, or 60 mol% or more, and may be contained at most 100 mol%, preferably 90 mol% or 80 mol% or less.

The reaction of the tetracarboxylic acid dianhydride and the dicarboxylic acid or dicarboxylic chloride with the diamine can be carried out according to a conventional method for producing a polyamideimide precursor, such as solution polymerization. Specifically, it can be produced by dissolving a diamine in an organic solvent, and then adding a tetracarboxylic acid dianhydride and a dicarboxylic acid or a dicarboxylic chloride to the resultant mixed solution to carry out a polymerization reaction. In this case, it is preferable to mix the tetracarboxylic acid dianhydride and the total amount of dicarboxylic acid or dicarboxylic chloride in a molar ratio of 1: 1.1 to 1.1: 1, or 1: 1.05 to 1.05: 1, Can be obtained.

The reaction can be carried out under an inert gas or a nitrogen stream and can be carried out under anhydrous conditions.

The polymerization reaction may be carried out at a temperature of -20 캜 to 60 캜, preferably 0 캜 to 30 캜.

Specific examples of the organic solvent that can be used in the polymerization reaction include? -Butyrolactone, 1,3-dimethyl-imidazolidinone, methyl ethyl ketone, cyclohexanone, cyclopentanone, Ketones such as methyl-2-pentanone; Aromatic hydrocarbons such as toluene, xylene, and tetramethylbenzene; Ethylene glycol monoethyl ether, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether , Glycol ethers (cellosolve) such as dipropylene glycol diethyl ether and triethylene glycol monoethyl ether; Examples of the solvent include ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, dipropylene glycol monomethyl ether acetate, ethanol, propanol, ethylene glycol, propylene glycol, (DMF), diethylformamide (DEF), N-methylpyrrolidone (NMP), N-ethylpyrrolidone (NEP), N-methylpyrrolidone N, N-dimethylmethoxyacetamide, dimethylsulfoxide, pyridine, dimethylsulfone, hexamethylphosphoramide, tetramethylurea, N-methylcarrolactam, tetra (2-methoxyethoxy) ethane, bis [2- (2-methoxyethoxy) ethane, (2-methoxyethoxy)] ether, and mixtures thereof. May be used.

More preferred are sulfoxide type solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide type solvents such as N, N-dimethylformamide and N, N-diethylformamide, N, N-dimethylacetamide , And N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, phenol-based solvents such as p-cresol, xylenol, halogenated phenol and catechol, and hexamethylphosphoramide and? -butyrolactone, which may be used alone or as a mixture. However, the present invention is not limited to this, and aromatic hydrocarbons such as xylene and toluene may be further used. In order to accelerate the dissolution of the polymer, about 50% by weight or less of the alkali metal salt or alkaline earth metal salt May be added.

The polyamideimide precursor composition prepared according to the above-described production method preferably contains a solid content in an amount such that the composition has an appropriate viscosity in consideration of processability such as coating properties in a film forming process. According to one embodiment, the content of the composition may be controlled such that the total polymer content is 5 to 25 wt%, preferably 5 to 20 wt%, more preferably 5 to 20 wt%, or 5 to 15 wt% % ≪ / RTI >

Or the polyamideimide precursor composition may have a viscosity of 500 cP or more, or 1,000 cP or more, preferably 3,000 cP or more, and the viscosity of the polyamideimide precursor composition is 30,000 cP or less, or 20,000 cP or less, Preferably 18,000 cP or less, or 15,000 cP or less. When the viscosity of the polyamideimide precursor composition is less than 500 cP or more than 30,000 cP, bubble generation and surface roughness may be poor during processing of the polyamideimide film, resulting in deterioration of optical properties.

The molecular weight of the polyamideimide according to the present invention may be 10,000 to 200,000 g / mol, or 20,000 to 100,000 g / mol, or 30,000 to 100,000 g / mol.

The molecular weight distribution (Mw / Mn) of the polyamideimide according to the present invention is preferably 1.1 to 2.5. When the imidization rate and weight average molecular weight or molecular weight distribution of the polyamideimide deviate from the above range, film formation may be difficult or the properties of the polyamideimide-based film such as transmittance, heat resistance and mechanical properties may deteriorate.

The polyamideimide precursor composition may be in the form of a solution dissolved in an organic solvent. When the polyamideimide precursor composition has such a form, for example, when a polyamideimide precursor is synthesized in an organic solvent, the solution may be the reaction solution itself , Or the reaction solution may be diluted with another solvent. When a polyamideimide precursor is obtained as a powder, it may be dissolved in an organic solvent to form a solution.

The powder of the polymer component may be dissolved in an organic solvent and heated at the time of preparing the solution. The heating temperature is preferably 20 to 150 占 폚, particularly preferably 20 to 80 占 폚.

Next, the polyamideimide precursor obtained as a result of the polymerization reaction is imidized to prepare a transparent polyamideimide film. At this time, the imidization process may be specifically a chemical imidization or thermal imidization process.

For example, it is preferable to add a dehydrating agent and an imidation catalyst to the polymerized polyamideimide precursor solution and heat the solution to a temperature of 50 to 100 ° C to imidize the solution by a chemical reaction, or to remove the alcohol while refluxing the solution And then imidizing the polyamide-imide.

In the above chemical imidization method, pyridine, triethylamine, picoline or quinoline may be used as the imidization catalyst. In addition, a nitrogen-containing heterocyclic compound substituted or unsubstituted, a nitrogen-containing heterocyclic compound N- A substituted or unsubstituted amino acid compound, an aromatic hydrocarbon compound having a hydroxyl group or an aromatic heterocyclic compound, particularly 1,2-dimethylimidazole, N-methylimidazole, N-benzyl- Lower alkyl imidazole such as methyl imidazole, 2-methyl imidazole, 2-ethyl-4-methyl imidazole and 5-methylbenzimidazole, and N-benzyl- Substituted pyridines such as pyridine, pyridine, pyridine, isothiazole, isothiazole, isothiazole, isoquinoline, 3,5-dimethylpyridine, 3,4-dimethylpyridine, 2,5-dimethylpyridine, 2,4-dimethylpyridine and 4- May be used.

As the dehydrating agent, an acid anhydride such as acetic anhydride may be used.

Alternatively, the precursor solution may be applied to a substrate and heat-treated on an oven or a hot plate at a temperature of 100 ° C to 300 ° C, or may be subjected to a multi-step heat treatment at various temperatures within the temperature range.

The organic solvent contained in the polyamideimide composition of the present invention may be the same as the aforementioned polymerization solvent.

In the present invention, a silane coupling agent, a crosslinkable compound, an imidization accelerator for promoting imidization efficiently, and the like may be added as long as the effect is not impaired.

By introducing a polyamide structure into the molecular structure of the polyimide having a rigid structure, the interchain packing is reduced by increasing the interchain distance, and the substitution with high electronegativity is bonded to the diamine structure to lower the charge transfer. A polyamideimide film excellent in color and transparency can be produced.

The polyamide-imide-based film may have a thickness of 20 to 100 탆, a haze of 2 or less, preferably 1 or less, more preferably 0.9 or less, and a film thickness of 10 to 30 탆 Having a yellow transmittance (YI) of about 7 or less, preferably about 5 or less, more preferably about 4 or less, or a transmittance of about 80% or more for light having a wavelength in the range of 380 to 760 nm And may be a transparent polyamideimide film. By having excellent light transmittance and yellowness as described above, it is possible to exhibit significantly improved transparency and optical characteristics.

In addition, the polyamide-imide-based films are in-plane retardation value (R _in) is from about 0 to about 100nm, or at least about 200nm retardation value (R _th) in a thickness direction or in-plane retardation value (R _in) is about 0 to And a retardation value (R _th ) in the thickness direction of about 300 nm or more.

The polyamide-imide-based film has a modulus of about 5 GPa or more, or about 5 to 9 GPa. The surface hardness of the polyamide-imide-based film is measured in accordance with JIS K5400 standard of measurement using a pencil hardness tester, The hardness can be confirmed by measuring the degree of scratching and pressing after 3 measurements. The surface hardness may be higher than HB or higher than F, preferably higher than H, more preferably higher than 2H. have.

Accordingly, another embodiment of the present invention provides a molded article comprising the polyamideimide copolymer.

The molded article may be a film, a fiber, a coating material, an adhesive, and the like, but is not limited thereto. The molded article may be formed by a dry-wet method, a dry method, a wet method, or the like using a composite composition of the copolymer and the inorganic particles, but is not limited thereto. Specifically, as described above, the molded article may be an optical film. In this case, the composition comprising the polyamide-imide copolymer may be applied to a substrate by a method such as spin coating, followed by drying and curing Can be easily produced.

INDUSTRIAL APPLICABILITY The polyamideimide according to the present invention can exhibit excellent colorless and transparent characteristics while maintaining the properties such as heat resistance and mechanical strength due to a rigid structure, and can be used as a substrate for devices, a cover substrate for displays, optical films, Can be used in various fields such as an IC (integrated circuit) package, an adhesive film, a multilayer FRC (flexible printed circuit), a tape, a touch panel, a protective film for an optical disc and the like, .

Specifically, by including the high-strength transparent polyamide-imide film according to the present invention, it is possible to provide a transparent polyamide-imide substrate useful as a flexible electronic device cover substrate which has excellent scratch resistance and can prevent life scratches in flexible electronic devices.

The transparent polyamideimide substrate according to the present invention is a transparent polyamideimide substrate,

High strength transparent polyamide imide film;

A transparent polyamideimide substrate formed on at least one surface of the polyamideimide film and including a cured layer of a polyisocyanate having an acrylate group and having 2 to 5 isocyanate groups.

According to one embodiment, the polyisocyanate may be represented by the following general formula (10).

[Chemical formula 10]

In Formula 10,

R < ₁₀ > has the structure of formula (11)

R ₁₂ is an alkyl group having 1 to 5 carbon atoms,

(11)

In Formula 11,

R ₁₁ is an alkyl group having 1 to 3 carbon atoms or a hydrogen atom,

n is an integer of 0 to 5, and m is an integer of 1 to 5.

According to another embodiment of the present invention, there is provided a display device including the molded article. Specifically, the display device may be a liquid crystal display device (LCD), an organic light emitting diode (OLED), or the like, but is not limited thereto.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Example 1 TFMB (1) / BPDA (0.5) _TPC (0.5)

N, N-dimethylacetamide (DMAc) (200 g) was charged into a stirrer through which a nitrogen gas stream was flowed. The reactor was maintained at 25 ° C and TFMB (2,2'-bis (trifluoromethyl) -4,4'- biphenyl diamine) To dissolve 21.7 g. 10 g of BPDA (3,3 ', 4,4'-biphenyltetracarboxylic dianhydride) is added to the TFMB solution at the same temperature and dissolved for a predetermined time and stirred. When sufficient agitation has been achieved, the temperature is lowered to 0 ° C and 7 g of TPC (terephthaloyl chloride) is added to continue stirring. Pyridine and acetic anhydride are added to the polyamideimide precursor solution prepared from the reaction, and the mixture is stirred sufficiently. Then, a precipitate is formed with a mixed solution of methanol and water, followed by drying. The dried polyamideimide powder was dissolved in DMAc to adjust the solid concentration to 13% to prepare a polyamideimide precursor solution.

The composition solution was spin-coated on a glass substrate to a thickness of about 30 탆. The glass substrate coated with the polyamideimide composition was placed in an oven, heated at a rate of 4 ° C / min, and cured at 300 ° C for 60 minutes. After completion of the curing process, the film formed on the glass substrate was peeled off to produce a film.

Example 2 TFMB (1) / BPDA (0.4) _TPC (0.6)

The procedure of Example 1 was repeated except that the composition of BPDA and TPC was 0.4 mol: 0.6 mol.

Example 3 TFMB (1) / BPDA (0.3) _TPC (0.7)

The procedure of Example 1 was repeated except that the composition of BPDA and TPC was 0.3 mol: 0.7 mol.

Comparative Example 1 TFMB (1) / BPDA (0.1) _TPC (0.9)

The procedure of Example 1 was repeated except that the composition of BPDA and TPC was 0.1 mol: 0.9 mol.

<Experimental Example 1>

The optical properties and measurements of the respective polyamide-imide films prepared in Examples 1 to 3 were measured in the following manner, and the results are shown in Table 1 below.

Haze was measured by the method according to ASTM D1003 using Haze Meter HM-150.

Yellowness Index (YI) was measured using a color difference meter (Color Eye 7000A).

The retardation in the plane direction (R _in ) and the retardation _{in the} thickness direction (R _th ) of the film were measured using Axoscan.

The surface hardness was measured three times per a pencil at a load of 750 gf according to the measuring standard JIS K5400 using a pencil hardness tester, and the degree of scratching and pressing was measured to confirm the hardness.

BPDA (0.1) /
TPC (0.9) BPDA (0.5) /
TPC (0.5) BPDA (0.4) /
TPC (0.6) BPDA (0.3) /
TPC (0.7) Comparative Example 1 Example 1 Example 2 Example 3 thickness
(탆)

Gelation 33 31 32 YI 3.4 3.1 2.9 Haze 0.83 0.79 0.75 Rth 520 553 652 Rin 67 67 67 Hardness (750gf) 2H
1/3 2H
0/3 2H
0/3

From the results of Examples 1 to 3, it can be seen that the polyamideimide according to the present invention has excellent haze characteristics and yellowing property as well as excellent hardness characteristics.

On the other hand, the polyamideimide of Comparative Example 1 was too thick to be formed into a film due to an increase in viscosity due to gelation on the polymerization solvent.

<Example 4>

In the formula 10 R ₁₀ is m is 1 ~ 5, n to have a whole number of 0 ~ 5, R ₁₁ comprises a structure of the group of the formula 11, R ₁₂ comprises a containing the group of acrylate polyisocyanate Was coated on one surface of the colorless transparent polyamide-imide film prepared in Example 2 using a dip coater and dried at a temperature of 80 캜 to obtain a coating film having a thickness of 10 탆. Then, the two wavelengths were simultaneously irradiated with energy of 100 mW / cm ² for 10 seconds by using an ultraviolet ray curing machine of 312 nm and 365 nm to form a cured film of a polyisocyanate containing acrylate on one surface to form a colorless transparent polyamide imide film / To obtain a colorless transparent polyamideimide film having a structure of a cured film of a polyisocyanate containing a rate.

&Lt; Example 5 >

A solution obtained by dissolving polysilazane in DBE (dibutyl ether) at 2 wt% was applied on one surface of the colorless transparent polyamideimide film to one side with wires, and dried at a temperature of about 80 DEG C to form a polysilazane film having a thickness of 300 nm.

Thereafter, the substrate was allowed to stand at room temperature for about 5 minutes, and thermally cured at a temperature of about 250 ° C to form a silicon oxide layer, thereby producing a substrate having a colorless transparent polyamideimide film / silicon oxide layer structure.

A cured film of polyisocyanate containing acrylate was formed on the colorless transparent polyamideimide film / silicon oxide layer in the same manner as in Example 4, and a cured film of polyisocyanate containing a colorless transparent polyamideimide film / silicon oxide layer / acrylate A colorless transparent polyamideimide film having a structure of a cured film of polyisocyanate was obtained.

<Experimental Example 2>

The properties were measured in the following manner, and the results are shown in Table 2.

 (1) Yellowness

The yellowness was measured using a spectrophotometer (CU-3700D, KONICA MINOLTA).

(2) Water permeability (g / m ² * day)

Water permeability (WVTR) was measured using a water-in-oil transient (MOCON / US / Aquatran-model-1).

(3) Pencil Hardness

The pencil hardness was measured by using an electric pencil hardness tester with a Mitsubishi Evaluation Pencil (UNI), drawing 5 times 50 mm at a rate of 180 mm / min under a load of 1 kg, and then measuring the pencil hardness without any scratches on the surface.

(5) Adhesiveness (detachable with tape 100 times)

And measured by tapping 100 times with a standard (ASTM D3359).

(6) Flexural properties

The substrate was placed in a circular tool with a diameter of 10 mm. The substrate was wound repeatedly. The film was observed by naked eyes and a microscope to see if the film was cracked.

(7) scratch resistance

The number of scratches was measured with a naked eye and an optical microscope after rubbing a 500 g load and a 100 mm speed at a speed of 50 mm / sec using a steelwool reciprocating 500 times.

YI Water permeability
(gm ^-2 / day) Pencil hardness
(1 kg 180 mm / min) Adhesiveness Bending characteristic
(Radius of curvature: 10 mm) Scratch resistance
(steel wool 500 times) Example 4 3.5 > 50 5H 5B OK 0 Example 5 3.7 > 50 5H 5B OK 0

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. It is therefore intended that the scope of the invention be defined by the claims appended hereto and their equivalents.

Claims (14)

A polyamideimide comprising a repeating structure represented by the following formula (1a) and a repeating structure represented by the formula (1b), wherein the repeating structure of formula (1a) and the repeating structure of formula (1b) are polymerized in a molar ratio of 2: 8 to 7:
[Formula 1a]

[Chemical Formula 1b]

In the above general formulas (1a) and (1b)
X ₁ is a tetravalent organic group derived from a tetracarboxylic dianhydride represented by the following formula (2)
(2)

X ₂ is a divalent organic group derived from a compound represented by the following formula (3)
(3)

In Formula 3,
Z is one selected from a hydroxyl group (-OH), a halide group selected from -Cl, -Br, -F, -I and an alkoxy group having 1 to 5 carbon atoms (-OR)
Y ₁ and Y ₂ are divalent organic groups derived from a diamine, at least one of which contains a divalent organic group represented by the following formula (4)
[Chemical Formula 4]

In Formula 4,
R ₁ and R ₂ each independently represent a halogen atom, -OH, -OH, -SH, nitro, -NH ₂ , An alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms,
Q is a single _{bond, -O-, -CR 18 R 19 -} , -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , A phenylene group and a combination thereof, wherein each of R ₁₈ and R ₁₉ is independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Is selected. The method according to claim 1,
Wherein the divalent organic group of the formula (4) is one selected from the compounds of the following formulas (4a) to (4d).

The method according to claim 1,
The polyamideimide obtained by polymerizing the repeating structure of Formula 1a and the repeating structure of Formula 1b in the form of a random copolymer. The method according to claim 1,
Wherein the repeating units represented by the formulas (1a) and (1b) include repeating units represented by the following formulas (1a-1) and (1a-1)
[Formula 1a-1]

[Chemical Formula 1b-1]

Comprising the steps of: stirring a diamine solution comprising a structure of Formula 4;
Adding a tetracarboxylic dianhydride having a structure represented by the following formula 2 and a compound represented by the following formula 3 in a molar ratio of 2: 8 to 7: 3 to the diamine solution to react with the diamine to prepare a polyamideimide precursor ; And
And imidizing the polyamideimide precursor, wherein the polyamideimide precursor is a polyamideimide precursor.
(2)

(3)

In Formula 3,
Z is one selected from a hydroxyl group (-OH), a halide group selected from -Cl, -Br, -F, -I and an alkoxy group having 1 to 5 carbon atoms (-OR)
[Chemical Formula 4]

In Formula 4,
R ₁ and R ₂ each independently represent a halogen atom, -OH, -OH, -SH, nitro, -NH ₂ , An alkyl group having 1 to 10 carbon atoms, a halogenoalkoxy having 1 to 4 carbon atoms, a halogenoalkyl having 1 to 10 carbon atoms, and an aryl group having 6 to 20 carbon atoms,
Q is a single _{bond, -O-, -CR 18 R 19 -} , -C (= O) -, -C (= O) O-, -C (= O) NH-, -S-, -SO 2 - , A phenylene group and a combination thereof, wherein each of R ₁₈ and R ₁₉ is independently selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, and a fluoroalkyl group having 1 to 10 carbon atoms Is selected. 6. The method of claim 5,
Wherein the compound of Formula 2 and Formula 3 and the diamine of Formula 4 are reacted at a molar ratio of 1: 1.1 to 1.1: 1. 6. The method of claim 5,
Wherein the compound of formula (3) is a compound of formula (3a) or (3b): &lt; EMI ID =
[Chemical Formula 3]

(3b)

A high strength transparent polyamideimide film comprising the polyamideimide of any one of claims 1 to 4. 9. The method of claim 8,
Wherein the polyamide-imide film has a haze of 2 or less and a pencil strength of 2H or more. 9. The method of claim 8,
Wherein the polyamide-imide film has a yellowing degree (YI) of 4 or less. A high strength transparent polyamide imide film according to claim 8;
A display cover substrate formed on at least one side of the polyamideimide film, the display cover substrate comprising an acrylate group and a cured layer of a polyisocyanate having 2 to 5 isocyanate groups. 12. The method of claim 11,
Wherein the polyisocyanate is represented by the following formula (10): &lt; EMI ID =
[Chemical formula 10]

In Formula 10,
R &lt; ₁₀ &gt; has the structure of formula (11)
R ₁₂ is an alkyl group having 1 to 5 carbon atoms,
(11)

In Formula 11,
R ₁₁ is an alkyl group having 1 to 3 carbon atoms or a hydrogen atom,
n is an integer of 0 to 5, and m is an integer of 1 to 5. 12. The method of claim 11,
And a silicon oxide layer formed between the transparent polyamideimide film and the cured layer. 12. The method of claim 11,
Wherein the silicon oxide layer is formed by coating and drying a solution comprising polysilazane and then curing the coated polysilazane.