KR102004660B1 - Polyimide Precursor Composition Comprising Crosslinkable Dianhydride Compound and Antioxidant, and Polyimide Film Prepared Therefrom - Google Patents

Abstract

The present invention is to provide a polyimide precursor composition comprising: a polyamic acid solution prepared by polymerizing one or more types of dianhydride monomers and one or more types of diamine monomers in an organic solvent; and an antioxidant of which 5 wt% decomposition temperature is 380°C or more. The dianhydride monomer comprises a crosslinkable dianhydride compound containing at least one triple bond in a molecular structure. The polyimide precursor composition of the present invention can improve thermal resistance and mechanical properties of a polyimide film.

Description

A polyimide precursor composition comprising a crosslinkable dianhydride-based compound and an antioxidant, a polyimide film prepared therefrom (a polyimide precursor composition, a crosslinkable dianhydride compound and an antioxidant, and a polyimide film prepared therefrom)

The present invention relates to a polyimide precursor composition comprising a crosslinkable dianhydride-based compound and an antioxidant, and a polyimide film produced therefrom.

Polyimide (PI) is a polymer material with thermal stability based on a rigid aromatic backbone, and has mechanical properties such as excellent strength, chemical resistance, weather resistance, and heat resistance based on the chemical stability of the imide ring.

In addition, polyimide is attracting attention as a high-functional polymer material applicable to a wide range of industrial fields such as electronic, communication, and optical due to excellent electrical properties such as insulation property and low dielectric constant.

In recent years, various electronic devices have become thinner, lighter, and smaller, and research has been conducted to use a thin and lightweight polyimide film having excellent flexibility as a display substrate that can replace an insulating material of a circuit substrate or a glass substrate for a display .

In particular, in the case of a polyimide film used for a circuit board or a display substrate manufactured at a high process temperature, it is necessary to secure a higher level of dimensional stability, heat resistance and mechanical properties.

An example of a method for securing such properties is to increase the molecular weight of the polyimide.

The higher the number of imide groups in the molecule, the better the heat resistance and the mechanical properties of the polyimide film, and the longer the polymer chain, the higher the ratio of the imide groups.

In order to prepare a polyimide having a high molecular weight, the precursor polyamic acid must be prepared in a high molecular weight, but the viscosity of the polyamic acid solution also increases as the molecular weight of the polyamic acid increases.

However, when the viscosity of the polyamic acid solution is excessively high, there is a problem that the flowability is lowered and the processability is very low.

On the other hand, a polyimide resin generally causes a chemical change, that is, an oxidation reaction, by light, heat, pressure, shear force or the like in the presence of oxygen. Such an oxidation reaction causes a change in physical properties due to the cleavage and crosslinking of molecular chains in the polyimide resin, resulting in a problem of deteriorating the heat resistance and mechanical properties of the polyimide film.

In order to solve such a problem, a method of adding a small amount of an additive such as an antioxidant has been used. The antioxidant has a role of stabilizing the polyimide resin by removing oxygen atoms of the already oxidized polyimide resin Phosphorus compounds and sulfur compounds are typically used.

However, in general, antioxidants which are generally used have a property of decomposing at a high temperature, and in particular, when manufacturing polyimide resins, high temperature heat treatment for imidization is usually accompanied, so that the antioxidant is decomposed, Or in some cases, does not exhibit such effects at all.

As described above, there are many difficulties in improving the properties required for the polyimide precursor composition and the polyimide resin produced therefrom. In particular, when one property is improved, other properties are generally lowered. Therefore, Is an ongoing challenge in the related art.

Therefore, there is a high demand for a polyimide precursor composition which is excellent in processability as described above, and which simultaneously satisfies heat resistance and mechanical properties of a polyimide film to be produced.

An object of the present invention is to provide a polyimide precursor composition and a polyimide film produced therefrom that simultaneously satisfy the heat resistance and mechanical properties of a polyimide film produced from the polyimic acid solution while keeping the viscosity of the polyamic acid solution low, .

According to one aspect of the present invention, there is provided a polyamic acid solution prepared by polymerizing at least one dianhydride monomer and at least one diamine monomer in an organic solvent, and an antioxidant, wherein the dianhydride monomer is a crosslinkable dianhydride A polyimide precursor composition containing a base compound is disclosed as an essential factor in the realization of a polyimide film satisfying such characteristics.

Therefore, the present invention has a practical purpose to provide a specific embodiment thereof.

The present invention relates to a polyamic acid solution prepared by polymerization of at least one dianhydride monomer and at least one diamine monomer in an organic solvent; And

5% by weight of an antioxidant having a decomposition temperature of 380 DEG C or higher,

Wherein the dianhydride monomer comprises a crosslinkable dianhydride-based compound, wherein the crosslinkable dianhydride-based compound comprises at least one triple bond in the molecular structure.

The present invention also relates to a polyimide precursor composition, wherein when the polyimide precursor composition is used, the processability can be improved due to the relatively low viscosity and high solids content, and the polyimide film produced therefrom exhibits excellent heat resistance and mechanical properties .

Thus, specific details for its implementation are described herein.

Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, it is to be understood that the constituent features of the embodiments described herein are merely the most preferred embodiments of the present invention, and are not intended to represent all of the inventive concepts of the present invention, so that various equivalents and variations It should be understood that examples may exist.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In this specification, the terms "comprising," "comprising," or "having ", and the like are intended to specify the presence of stated features, integers, But do not preclude the presence or addition of one or more other features, integers, steps, components, or combinations thereof.

As used herein, "dianhydride" is intended to include its precursors or derivatives, which may not technically be dianhydrides, but nevertheless react with diamines to form polyamic acids And this polyamic acid can be converted back to polyimide.

As used herein, "diamine" is intended to include precursors or derivatives thereof, which, although not technically diamines, will nonetheless react with dianhydride to form a polyamic acid, / RTI >

Where an amount, concentration, or other value or parameter is given herein as an enumeration of ranges, preferred ranges, or preferred upper and lower preferred values, it is understood that any pair of any upper range limits It is to be understood that the present invention specifically discloses all ranges formed by preferred values and any lower range limits or preferred values.

Where a range of numerical values is referred to in this specification, unless otherwise stated, the range is intended to include all the integers and fractions within the endpoint and its range.

The scope of the present invention is not intended to be limited to the specific values that are mentioned when defining the scope.

First Aspect: Polyimide precursor composition

The polyimide precursor composition according to the present invention is a polyamic acid solution prepared by polymerizing at least one dianhydride monomer and at least one diamine monomer in an organic solvent; And

5% by weight of an antioxidant having a decomposition temperature of 380 DEG C or higher,

Wherein the dianhydride monomer comprises a crosslinkable dianhydride-based compound, wherein the crosslinkable dianhydride-based compound comprises at least one triple bond in the molecular structure.

Based on the total weight of the polyimide precursor composition.

When the solid content of the polyimide precursor composition exceeds the above range, the viscosity of the polyimide precursor composition is inevitably increased. Conversely, when the solid content of the polyimide precursor composition is less than the above range , There is a problem that a large amount of solvent must be removed in the curing process, thereby increasing manufacturing cost and process time.

In addition, the polyimide precursor composition may have a viscosity at 23 占 폚 in the range of 1,000 to 20,000 cP, specifically in the range of 2,000 to 10,000 cP, more specifically 3,000 to 6,000 cP.

A polyimide precursor composition having such a viscosity has an advantage in that it can be easily handled in terms of flowability and may be advantageous for film formation. Specifically, when the viscosity of the polyimide precursor composition exceeds the range, it is necessary to apply a higher pressure by friction with the pipe when the polyimide precursor composition is moved through the pipe during the manufacturing process of the polyimide film Therefore, the process cost may be increased and the handling property may be deteriorated. Also, the higher the viscosity, the more time and expense may be required in the mixing process.

On the other hand, when the viscosity of the polyimide precursor composition is lower than the above-mentioned range, a large amount of solvent must be removed during the curing process, resulting in a problem of increased manufacturing cost and process time.

On the other hand, the content of the dianhydride monomer may be 88 to 99.5 mol% based on 100 mol% of the diamine monomer, and the content of the crosslinkable dianhydride compound may be 0.5 to 12 mol%.

More specifically, the content of the dianhydride monomer may be 90 to 99 mol%, and the content of the crosslinkable dianhydride compound may be 1 to 10 mol% based on 100 mol% of the diamine monomer.

When a polyimide precursor composition is prepared by adding a crosslinkable dianhydride compound so as to exceed the above range, the flexibility of the polyimide film may be lowered and the formation of the film may be difficult. In the case where the polyimide precursor composition is below the above range, The heat resistance and mechanical properties of the polyimide film to be produced may be deteriorated.

In one specific example, the crosslinkable dianhydride-based compound may be a compound represented by the following formula (1).

(1)

(One)

Wherein L is a C2-C6 alkynyl group,

R ₁ and R ₂ each independently may be selected from the group consisting of an alkyl group, an aryl group, a carboxylic acid group, a hydroxyl group, a fluoroalkyl group, and a sulfonic acid group of C ₁ -C 3,

When R ₁ and R ₂ are plural, they may be the same or different from each other,

n and m are each independently an integer of 0 to 3;

When the substituent of the benzene ring in Formula 1 is not specifically specified, it means hydrogen.

In a more specific example, the crosslinkable dianhydride-based compound may be Ethynylbisphthalic anhydride (EBPA) represented by the following formula 1-1.

(1-1)

(1-1)

Herein, the triple bond contained in the molecular structure of the crosslinkable dianhydride compound is composed of three sigma (σ) bonds and two pi (π) bonds in which three electron pairs are involved in bonding, Due to the π bond, the triple bond is unsaturated and has a property of easily causing an addition reaction or a polymerization reaction and easily being cleaved.

The polyimide precursor composition of the present invention comprises a crosslinkable dianhydride-based compound containing the triple bond, wherein the polyimide precursor composition produced by the polymerization reaction of the dianhydride monomer and the diamine monomer is a crosslinkable dianhydride- And may include two or more polyamic acid chains having a triple bond derived from a base compound.

Since the polyimide precursor composition containing the polyamic acid chain having the above structure has no crosslinking between the triple bonds in the solution state, the polyimide precursor composition is similar to a conventional polyimide precursor composition not derived from the crosslinkable dianhydride compound Can be expressed.

However, in the heat treatment for imidization, one or more crosslinks can be formed by a radical reaction between the triple bonds contained in the different polyamic acid chains, so that after the conversion into the polyimide, The mechanical properties and heat resistance of the polyimide film can be remarkably improved as compared with a conventional polyimide film.

In a specific example, the polyimide precursor composition comprises a first polyamic acid chain having a triple bond derived from a crosslinkable dianhydride-based compound, a second polyamic acid chain having a triple bond derived from a crosslinkable dianhydride-based compound, And may be a structure including a plurality of polyamic acid chains having a triple bond.

In the polyimide precursor composition, when heat treatment for imidization is carried out, radicals derived from pi bonds bonded to the first triple bond included in the first polyamic acid chain and the second triple bond contained in the second polyamic acid chain are formed And the first polyamic acid chain and the second polyamic acid chain can be crosslinked as a form in which highly reactive radicals cross each other by a radical reaction.

As a result, the first polyamic acid chain and the second polyamic acid chain can form crosslinks between the polyimide chains by the above-mentioned reaction in the imidization process, and in addition to the first polyamic acid chain and the second polyamic acid chain Since a plurality of polyamic acid chains each include a plurality of triple bonds, the above-mentioned crosslinking can be formed between them.

Through such crosslinking, mechanical properties and heat resistance can be remarkably improved as compared with a polyimide film not containing crosslinking.

According to the present invention, when a polyimide precursor composition is prepared using a crosslinkable dianhydride-based compound instead of preparing a polyimide precursor composition having a very high molecular weight to improve the heat resistance and mechanical properties of the polyimide film, Even if a polyimide precursor composition having a low viscosity is used, heat resistance and mechanical properties similar to those of a polyimide film produced from a polyimide precursor composition having a high viscosity can be exhibited.

Further, when a polyimide precursor composition having a low viscosity is used, the processability is further improved.

On the other hand, the antioxidant may have a decomposition temperature of 5% by weight of 380 ° C or more, specifically 5% by weight of decomposition temperature of 400 ° C or more.

Specifically, the antioxidant may include a compound represented by the following general formula (2).

(2)

(2)

In Formula 2, R _1a to R _6a each independently may be selected from the group consisting of an alkyl group, an aryl group, a carboxyl group, a hydroxyl group, a fluoroalkyl group, and a sulfonic acid group of C1-C3,

When there are plural R _1a to R _6a , they may be the same or different,

n1 is an integer of 1 to 4,

m1 to m6 each independently represent an integer of 0 to 3;

In the formula (2), when the substituent of the benzene ring is not particularly specified, it means hydrogen.

In one specific example, in Formula 2, n1 is 1, and m1 to m6 may be 0, and more specifically, the antioxidant may be a compound represented by Formula 2-1 below.

(2-1)

(2-1)

Since such an antioxidant has low volatility and excellent thermal stability, it does not decompose or volatilize during the production process of the polyimide film, so that the effect of preventing the oxidation of the amide group or the imide group of the polyimide film in the polyimide precursor composition .

On the contrary, in the case of an antioxidant having a decomposition temperature of 5 wt% at 380 DEG C or lower, the antioxidant decomposed by high temperature during the production process of the polyimide film can not exhibit the effect of the introduction of the antioxidant as described above.

The antioxidant may be added in an amount of 0.1 to 2.5 parts by weight based on 100 parts by weight of the solid content of the polyimide precursor composition, and more specifically, 0.1 to 2.0 parts by weight with respect to 100 parts by weight of the solid content of the polyimide precursor composition.

If the content of the antioxidant exceeds the above range, the heat resistance may be lowered, and deposition or blooming may occur in the polyimide film, which may deteriorate the mechanical properties of the polyimide film. Which is undesirable.

On the other hand, when the content of the antioxidant is less than the above range, the antioxidant effect can not be sufficiently exhibited.

On the other hand, as described above, the polyimide precursor composition can be produced by polymerization reaction of one or more dianhydride monomers and one or more diamine monomers.

The dianhydride monomer that may be used in the preparation of the polyamic acid of the present invention may be an aromatic tetracarboxylic dianhydride.

The aromatic tetracarboxylic dianhydride may be pyromellitic dianhydride (or PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (or s-BPDA), 2,3 , 3 ', 4'-biphenyltetracarboxylic dianhydride (or? -BPDA), oxydiphthalic dianhydride (or ODPA), diphenylsulfone-3,4,3' Bis (3,4-dicarboxyphenyl) -1,1,1,3,3, < RTI ID = 0.0 > 3,3 ', 4'-benzophenone tetracarboxylic dianhydride, 3,3', 4,4'-benzophenone tetracarboxylic dianhydride, 3,3 ', 4,4'-benzophenone tetracarboxylic dianhydride, (Or BTDA), bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, p- Monoester acid Hydride), p-biphenylene bis (trimellitic monoester acid anhydride), m-terphenyl-3,4,3 ', 4'-tetracarboxylic dianhydride, p- Bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxy Bis (3,4-dicarboxyphenoxy) phenyl] propane dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) biphenyl dianhydride, 2,2- (BPADA), 2,3,6,7-naphthalenetetracarboxylic acid dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4 '- (2,2-hexafluoro Diisopropylidene) diphthalic acid dianhydride, and the like. These may be used alone or in combination of two or more thereof as desired.

These dianhydride monomers may be used alone or in combination of two or more thereof as desired. However, dianhydride monomers that can be particularly preferably used in the present invention include pyromellitic dianhydride (PMDA), 3,3 ', 4,4 At least one selected from the group consisting of 2'-biphenyltetracarboxylic dianhydride (s-BPDA) and 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride (? -BPDA) . ≪ / RTI >

The diamine monomers that can be used in the production of the polyamic acid of the present invention are aromatic diamines, which can be categorized as follows.

1) 1,4-diaminobenzene (or paraphenylenediamine, p-PDA), 1,3-diaminobenzene, 2,4-diaminotoluene, 2,6-diaminotoluene, 3,5- Diamines having one benzene nucleus in structure, such as diaminobenzoic acid (or DABA), and the like; diamines of relatively rigid structure;

2) diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether (or oxydianiline, ODA) and 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylmethane (Methylenediamine), 3,3'-dimethyl-4,4'-diaminobiphenyl, 2,2'-dimethyl-4,4'- diaminobiphenyl, 2,2'-bis (trifluoromethyl ) -4,4'-diaminobiphenyl, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, 3,3'-dicarboxy-4,4'-diaminodiphenylmethane , 3,3 ', 5,5'-tetramethyl-4,4'-diaminodiphenylmethane, bis (4-aminophenyl) sulfide, 4,4'- diaminobenzanilide, Dimethylbenzidine (or o-tolidine), 2,2'-dimethylbenzidine (or m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxy Benzidine, 3,3'-diaminodiphenyl ether, 3,3'-diaminodiphenylsulfide, 3,4'-diaminodiphenylsulfide, 4,4'-diaminodiphenylsulfide, 3,3 ' -Diaminodiphenylsulfone, 3,4'-diamino Phenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone , 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 2,2-bis -Aminophenyl) propane, 2,2-bis (4-aminophenyl) propane, 2,2-bis (3-aminophenyl) -1,1,1,3,3,3-hexafluoropropane , 2,2-bis (4-aminophenyl) -1,1,1,3,3,3-hexafluoropropane, 3,3'-diaminodiphenylsulfoxide, 3,4'-diamino Diamines having two benzene nuclei in structure, such as diphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, and the like;

(3) aminophenyl) benzene, 1,4-bis (3-aminophenyl) benzene, Bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene (or TPE- Benzene (or TPE-Q), 1,3-bis (3-aminophenoxy) -4-trifluoromethylbenzene, 3,3'-diamino- , 3'-diamino-4,4'-di (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenylsulfide) benzene, Benzene, 1,4-bis (4-aminophenylsulfide) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3- Benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 1,4- Benzene having three structural benzene nuclei, such as bis [2- (4-aminophenyl) isopropyl] benzene, Amine;

4) bisphenols such as 3,3'-bis (3-aminophenoxy) biphenyl, 3,3'-bis (4-aminophenoxy) biphenyl, 4,4'- (4-aminophenoxy) phenyl] ether, bis [4- (aminophenoxy) phenyl] (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- , Bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) (4-aminophenoxy) phenyl] sulfone, bis [3- (4-aminophenoxy) (3-aminophenoxy) phenyl] methane, bis [3- (4-aminophenoxy) phenyl] methane, bis [4- Phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 2,2-bis [3- Phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2- (BAPP), 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2- -Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) phenyl] Such as 3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, Diamine with four benzene nuclei in structure.

The diamine monomers that can be particularly preferably used in the present invention include para-phenylenediamine (p-PDA), 1,3-diaminobenzene (MPD) , 2,4-diaminotoluene, 2,6-diaminotoluene, and 3,5-diaminobenzoic acid (DABA).

When the amount of the dianhydride monomer to be added is lower than or equal to the above range, the polymerization is terminated before the desired molecular weight is reached, or a polyimide precursor composition capable of forming a polyimide film by generating a large number of low molecular weight oligomers It is difficult to implement.

In the polyimide precursor composition, the diamine monomer and the dianhydride monomer may be substantially equimolarly charged. More specifically, the amount of the dianhydride monomer may be 99 mol% or less based on 100 mol% of the diamine monomer. Based on 100 mol% of the diamine monomer, and the amount of the dianhydride monomer may be 99 mol% to 99.9 mol% based on 100 mol% of the diamine monomer.

When the amount of the dianhydride monomer to be added is lower than or equal to the above range, the polymerization is terminated before the desired molecular weight is reached, or a polyimide precursor composition capable of forming a polyimide film by generating a large number of low molecular weight oligomers It is difficult to implement.

Second aspect: Production method of polyimide film and polyimide film

The method for producing a polyimide film according to the present invention comprises:

(a) introducing at least one dianhydride monomer and at least one diamine monomer into an organic solvent and polymerizing to prepare a polyamic acid solution;

(b) mixing the polyamic acid solution with an antioxidant to prepare a polyimide precursor composition;

(c) forming the polyimide precursor composition on a support and drying the polyimide precursor composition to prepare a gel film, and imidizing the gel film to produce a polyimide film,

The dianhydride monomer includes a crosslinkable dianhydride-based compound, and the crosslinkable dianhydride-based compound may include at least one triple bond in the molecular structure.

As described above, the polyamic acid chain included in the polyimide precursor composition comprises one or more polyamic acid chains having a triple bond derived from a crosslinkable dianhydride-based compound, and in the step (c) , One or more crosslinks can be formed by a radical reaction between the triple bonds contained in the different polyamic acid chains.

That is, it is not necessary to excessively increase the molecular weight in the state of the polyimide precursor composition in order to improve the heat resistance and the mechanical properties of the polyimide film to be produced by crosslinking between the triple bonds, Heat resistance and mechanical properties similar to those of the polyimide film prepared from the polyimide film can be secured.

The preparation of the polyamic acid solution in the present invention can be carried out, for example,

(1) a method in which the whole amount of the diamine monomer is put into a solvent, and then the dianhydride monomer is added so as to be substantially equimolar with the diamine monomer, and the mixture is polymerized;

(2) a method in which the whole amount of the dianhydride monomer is put into a solvent, and then, the diamine monomer is added so as to be substantially equimolar with the dianhydride monomer and polymerized;

(3) After adding some of the components of the diamine monomer into the solvent, a part of the dianhydride monomer is mixed with the reaction component in a ratio of about 95 to 105 mol%, and then the remaining components of the diamine monomer are added. A method in which a dianhydride monomer component is added so that the diamine monomer and the dianhydride monomer are substantially equimolar and polymerized;

(4) After adding the dianhydride monomer into the solvent, the dianhydride monomer component is added to the reaction component in a proportion of 95 to 105 mol% of the diamine monomer, and then the remaining diamine monomer component To thereby polymerize the diamine monomer and the dianhydride monomer so that the diamine monomer and the dianhydride monomer are substantially equimolar;

(5) a step of reacting a part of the diamine monomer component and a part of the dianhydride monomer component in the solvent so that one of them is excessive to form the first composition, and in the other solvent, a part of the diamine monomer component and a part of the dianhydride monomer component To form a second composition, mixing the first and second compositions, and completing the polymerization, wherein when the diamine monomer component is excessive at the time of forming the first composition, the second composition The dianhydride monomer component is excessively used, and when the dianhydride monomer component is excessive in the first composition, the diamine monomer component is excessively used in the second composition, and the first and second compositions are mixed and used in these reactions So that the total diamine monomer component and the dianhydride monomer component are substantially equimolar It can be joined to the methods.

However, the polymerization method is not limited to the above examples, and any known method may be used.

The dianhydride monomer may be appropriately selected from the examples described above. Specifically, in addition to the crosslinkable dianhydride-based compound, pyromellitic dianhydride (PMDA), 3,3 ', 4,4'- At least one selected from the group consisting of biphenyltetracarboxylic dianhydride (s-BPDA) and 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride (? -BPDA) .

The diamine monomer may be appropriately selected from the examples described above. Specifically, the diamine monomer may be selected from the group consisting of paraphenylenediamine (p-PDA), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6 -Diaminotoluene, and 3,5-diaminobenzoic acid (DABA) can be preferably used.

In the production process of the present invention, the polyimide film can be produced through thermal imidization and the chemical imidation process can also be carried out.

The thermal imidization method is a method in which a chemical catalyst is excluded and a imidization reaction is induced by a heat source such as hot air or an infrared drier.

The thermal imidization may include the step (c), and the gel film may be heat-treated at a variable temperature ranging from 100 to 600 ° C in the step (c) Specifically, the amyl acid present in the gel film can be imidized by heat treatment at 200 to 500 ° C, more specifically 300 to 500 ° C.

However, even in the step (c) of forming the gel film, a part (about 0.1 to 10 mol%) of amic acid may be imidized, and in this step (c) The polyamic acid composition can be dried at a variable temperature, and this can also be included in the category of the thermal imidation process.

The polyimide film according to the present invention has a thermal decomposition temperature of 550 to 620 占 폚, a thermal expansion coefficient (CTE) of 2.0 to 8.0 ppm / 占 폚, a glass transition temperature of 400 占 폚 or higher , A elongation of 13% or more, a tensile strength of 270 MPa or more, and a thickness of 10 to 20 탆.

More specifically, the polyimide film of the present invention may have a glass transition temperature of 417 캜 or higher.

When a chemical imidization method is used in parallel, a polyimide film can be produced by using a dehydrating agent and an imidizing agent according to a method known in the art.

The present invention also provides an electronic device comprising the polyimide film, wherein the electronic device may be an electronic device including a flexible circuit board or a display substrate.

The polyimide precursor composition according to the present invention includes a crosslinkable dianhydride-based compound containing at least one triple bond in the molecular structure, so that when the heat treatment for imidization is carried out, the triple bonds contained in the different polyamic acid chains At least one cross-linking can be formed by radical reaction between the polyimide film and the polyimide film, whereby the heat resistance and mechanical properties of the polyimide film can be improved.

Further, the polyimide precursor composition according to the present invention has improved heat resistance and mechanical properties at the time of heat treatment for imidization, so that the viscosity of the polyimide precursor composition can be kept low, and thereby the processability can be remarkably improved .

In addition, the antioxidant having a decomposition temperature of 5 wt% in the polyimide precursor composition having a decomposition temperature of 380 DEG C or higher has low volatility and excellent thermal stability, so that the amide in the polyimide precursor composition is not decomposed or volatilized during the production process of the polyimide film, It is possible to prevent oxidation of the imide groups of the polyimide film or the polyimide film, thereby minimizing changes in the physical properties of the polyimide film.

Such a polyimide film has an advantage of satisfying heat resistance and mechanical properties required for a display substrate.

Best Mode for Carrying Out the Invention Hereinafter, the function and effect of the present invention will be described in more detail through specific examples of the present invention. It is to be understood, however, that these embodiments are merely illustrative of the invention and are not intended to limit the scope of the invention.

The abbreviations used in Examples and Comparative Examples are as follows.

- biphenyl tetracarboxylic acid dianhydride: BPDA

- pyromellitic dianhydride: PMDA

- Ethynyl Bisulphatic Anhydride: EBPA

-Paraphenylenediamine: p-PDA

- N-methylpyrrolidone: NMP

≪ Example 1 >

NMP was introduced into a 500-ml reactor equipped with a stirrer and a nitrogen inlet / outlet tube, the temperature of the reactor was set at 30 ° C, p-PDA as a diamine monomer, BPDA as a dianhydride monomer, It is confirmed that completely dissolved by injecting 1 mole of EBPA per 100 moles of PDA.

Stirring was continued for 120 minutes while the temperature was raised to 40 占 폚 in a nitrogen atmosphere to prepare a polyamic acid solution having a viscosity of 6100 cP at 23 占 폚.

After the temperature of the reactor was set to 50 ° C, the compound of formula (2-1) having a decomposition temperature of about 402 ° C as a 5 wt% antioxidant was added to the polyamic acid solution and sufficiently stirred until the reaction was completed. NMP was added so that the content was about 15% by weight and the viscosity was about 3,700 cP, and the molar ratio of the diamine monomer, dianhydride monomer, and crosslinkable dianhydride compound was 100: 99: 1, A polyimide precursor composition containing 0.5 part by weight of an antioxidant was prepared.

(2-1)

(2-1)

The polyimide precursor composition was subjected to high speed rotation at 1,500 rpm or more to remove bubbles. Thereafter, the defoamed polyimide precursor composition was applied to the glass substrate using a spin coater. Thereafter, the gel film was dried in a nitrogen atmosphere and at a temperature of 120 DEG C for 30 minutes to prepare a gel film. The gel film was heated up to 450 DEG C at a rate of 2 DEG C / minute, heat-treated at 450 DEG C for 60 minutes, And cooled at a rate of 2 DEG C / minute to obtain a polyimide film.

Thereafter, the polyimide film was peeled off from the glass substrate by dipping in distilled water. The thickness of the produced polyimide film was 15 탆. The thickness of the polyimide film was measured using an Anritsu film thickness tester.

≪ Examples 2 to 14 and Comparative Examples 1 to 6 >

A polyimide film was prepared in the same manner as in Example 1, except that the viscosity of the monomer, additive and polyimide precursor composition was changed as shown in Table 1, respectively.

≪ Comparative Example 7 &

A polyimide film was prepared in the same manner as in Example 1, except that the compound represented by the following formula (A) was added in place of the compound of the formula (2-1) as an antioxidant at a decomposition temperature of 5 wt% .

(A)

(A)

≪ Comparative Example 8 >

A polyimide film was prepared in the same manner as in Example 1, except that the compound of the formula (B) having a decomposition temperature of 5% by weight was added at a temperature of about 338 ° C instead of the compound of the formula (2-1) as an antioxidant .

(B)

(B)

p-PDA
(mole%) BPDA
(mole%) PMDA
(mole%) EBPA
(mole%) Antioxidant Viscosity
(cP) Kinds content
(Parts by weight) Example 1 100 99 - One 2-1 0.5 3,700 Example 2 100 99 - One 2-1 One 3,700 Example 3 100 95 - 5 2-1 0.5 3,700 Example 4 100 90 - 10 2-1 0.5 3,700 Example 5 100 99 - One 2-1 0.1 3,700 Example 6 100 99 - One 2-1 2 3,700 Example 7 100 95 - 5 2-1 One 3,700 Example 8 100 50 49 One 2-1 One 3,600 Example 9 100 50 45 5 2-1 One 3,600 Example 10 100 99.5 - 0.5 2-1 0.5 3,700 Example 11 100 88 - 12 2-1 0.5 3,700 Example 12 100 99 - One 2-1 2.1 3,700 Example 13 100 99 - One 2-1 2.5 3,700 Example 14 100 50 49 One 2-1 2.1 3,600 Comparative Example 1 100 99 - One - - 3,700 Comparative Example 2 100 100 - - 2-1 0.5 3,700 Comparative Example 3 100 100 - - - - 3,700 Comparative Example 4 100 50 49 One - - 3,600 Comparative Example 5 100 50 50 - 2-1 One 3,600 Comparative Example 6 100 50 50 - - - 3,600 Comparative Example 7 100 99 - One A 0.5 3,700 Comparative Example 8 100 99 - One Formula B 0.5 3,700

<Experimental Example 1: Evaluation of physical properties>

The physical properties of the polyimide films prepared in Examples 1 to 14 and Comparative Examples 1 to 8 were measured by the following method, and the results are shown in Table 2 below.

(1) Coefficient of thermal expansion (CTE)

Using a TA thermomechanical analyzer Q400 model, the polyimide film was cut to a width of 2 mm and a length of 10 mm. The film was stretched at a rate of 10 ° C / min under a nitrogen atmosphere at a rate of 0.05 N Lt; 0 &gt; C and then cooled at a rate of 10 [deg.] C / min.

(2) a thermal decomposition temperature (TD) of 1 wt%

A TA thermogravimetric analyzer Q50 model was used. The polyimide film was heated to 150 DEG C at a rate of 10 DEG C / min under a nitrogen atmosphere, and was then kept at 30 DEG C for 30 minutes to remove moisture. Thereafter, the temperature was raised to 600 ° C at a rate of 10 ° C / min to measure the temperature at which the weight reduction of 1% occurred.

(3) Glass transition temperature (Tg)

Using a dynamic mechanical analyzer Q800 model, the polyimide film was cut into a width of 4 mm and a length of 20 mm, and then heated at a rate of 5 ° C / min in a nitrogen atmosphere, at a temperature of 550 ° C The glass transition temperature was measured under the conditions. The glass transition temperature was determined as the maximum peak of tan? Calculated according to the ratio of storage modulus and loss modulus.

(4) Elongation

The polyimide film was cut to a width of 10 mm and a length of 40 mm, and then the elongation was measured using an Instron5564 UTM instrument of Instron by the ASTM D-882 method.

(5) Tensile strength

The polyimide film was cut to a width of 10 mm and a length of 40 mm, and then the tensile strength was measured by an Instron5564 UTM instrument of Instron using the ASTM D-882 method. The crosshead speed was measured at a rate of 5 mm / min.

CTE
(ppm / DEG C) TD
(° C) Tg
(° C) Elongation
(%) The tensile strength
(MPa) Example 1 8 565 430 18 302 Example 2 6 568 441 22 350 Example 3 5.3 570 435 20 324 Example 4 4.7 562 430 17 295 Example 5 7 560 410 16 290 Example 6 8 555 420 15 280 Example 7 5.1 573 446 23 368 Example 8 3 568 435 16 298 Example 9 2.5 568 440 18 305 Example 10 10 555 414 16 293 Example 11 5.5 560 416 15 283 Example 12 15 553 415  14 273 Example 13 13 551 410 13 270 Example 14 10 550 410  13  271 Comparative Example 1 12 545 380 13 268 Comparative Example 2 20 557 398 10 260 Comparative Example 3 25 540 368 10 268 Comparative Example 4 8.5 547 382 10 256 Comparative Example 5 13 555 390 8 245 Comparative Example 6 15 538 370 7 250 Comparative Example 7 10 555 399 14 275 Comparative Example 8 11 548 388 12 267

Referring to Table 2, it can be confirmed that the embodiments satisfying the range of the present invention are excellent in heat resistance and mechanical properties. On the other hand, it can be confirmed that comparative examples outside the scope of the present invention do not satisfy at least one of heat resistance and mechanical properties.

Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention.

Claims (16)

A polyamic acid solution prepared by polymerizing at least one dianhydride monomer and at least one diamine monomer in an organic solvent; And
5% by weight of an antioxidant having a decomposition temperature of 380 DEG C or higher,
Wherein the dianhydride monomer comprises a crosslinkable dianhydride-based compound, wherein the crosslinkable dianhydride-based compound comprises at least one triple bond in the molecular structure,
Wherein the antioxidant comprises a compound represented by the following formula (2): &lt; EMI ID =

(2)
In Formula 2, R _1a to R _6a each independently may be selected from the group consisting of an alkyl group, an aryl group, a carboxyl group, a hydroxyl group, a fluoroalkyl group, and a sulfonic acid group of C 1 -C 3,
When there are plural R _1a to R _6a , they may be the same or different,
n1 is an integer of 1 to 4,
m1 to m6 each independently represent an integer of 0 to 3; The method according to claim 1,
Wherein the crosslinkable dianhydride compound is represented by the following formula (1): &lt; EMI ID =

(One)
Wherein L is a C2-C6 alkynyl group,
R ₁ and R ₂ each independently may be selected from the group consisting of an alkyl group, an aryl group, a carboxylic acid group, a hydroxyl group, a fluoroalkyl group, and a sulfonic acid group of C ₁ -C 3,
When R ₁ and R ₂ are plural, they may be the same or different from each other,
n and m are each independently an integer of 0 to 3; 3. The method of claim 2,
The crosslinkable dianhydride-based compound is Ethynylbisphthalic anhydride (EBPA) Polyimide precursor composition. The method according to claim 1,
Wherein the polyimide precursor composition comprises two or more polyamic acid chains having a triple bond derived from a crosslinkable dianhydride-based compound,
Wherein the polyimide precursor composition forms one or more crosslinks by radical reaction between the triple bonds contained in the different polyamic acid chains during the heat treatment for imidization. The method according to claim 1,
The content of the dianhydride monomer is 88 to 99.5 mol%, and the content of the crosslinkable dianhydride compound is 0.5 to 12 mol% based on 100 mol% of the diamine monomer. The method according to claim 1,
The content of the dianhydride monomer is 90 to 99 mol%, and the content of the crosslinkable dianhydride compound is 1 to 10 mol%, based on 100 mol% of the diamine monomer. The method according to claim 6,
Wherein the antioxidant has a decomposition temperature of 5 wt% or more and 400 DEG C or more. delete The method according to claim 1,
Wherein n1 is 1 and m1 to m6 are 0 in the general formula (2). The method according to claim 1,
Wherein the polyimide precursor composition comprises 0.1 to 2.5 parts by weight of an antioxidant based on 100 parts by weight of the solid content of the polyimide precursor composition. The method according to claim 1,
Wherein the polyimide precursor composition comprises 0.1 to 2 parts by weight of an antioxidant based on 100 parts by weight of the solid content of the polyimide precursor composition. A polyimide film produced from the polyimide precursor composition of any one of claims 1 to 7 and 9 to 11. 13. The method of claim 12,
Wherein the polyimide film has a pyrolysis temperature of 1 to 5%
A coefficient of thermal expansion (CTE) of 2.0 to 8.0 ppm /
A glass transition temperature of 400 DEG C or higher,
The elongation is 13% or more,
A tensile strength of 270 MPa or more,
A polyimide film having a thickness of 10 to 20 占 퐉. 14. The method of claim 13,
Wherein the polyimide film has a glass transition temperature of 417 캜 or higher. A method for producing a polyimide film according to claim 12,
(a) introducing at least one dianhydride monomer and at least one diamine monomer into an organic solvent and polymerizing to prepare a polyamic acid solution;
(b) mixing the polyamic acid solution with an antioxidant to prepare a polyimide precursor composition;
(c) forming the polyimide precursor composition on a support and drying the polyimide precursor composition to prepare a gel film, and imidizing the gel film to produce a polyimide film,
Wherein the dianhydride monomer comprises a crosslinkable dianhydride-based compound, wherein the crosslinkable dianhydride-based compound comprises at least one triple bond in the molecular structure. 14. An electronic device comprising a polyimide film according to claim 12.