WO2019160218A1

WO2019160218A1 - Polyamic acid composition having improved storage stability, manufacturing method for polyimide film using same, and polyimide film manufactured by means of same

Info

Publication number: WO2019160218A1
Application number: PCT/KR2018/012258
Authority: WO
Inventors: 황인환; 김주영; 이익상; 임현재
Original assignee: 에스케이씨코오롱피아이 주식회사
Priority date: 2018-02-19
Filing date: 2018-10-17
Publication date: 2019-08-22
Also published as: KR101949316B1; TW201934613A; TWI714944B

Abstract

The present invention provides a polyamic acid composition having excellent storage stability, a manufacturing method for a polyimide film using same, and a polyimide film, the polyamic acid composition comprising an organic solvent and polyamic acid, at least a part of the hydroxyl groups of the polyamic acid having been substituted by an alkoxy group by means of an alcoholysis reaction with an alcohol additive.

Description

Polyamic acid composition with improved storage stability, manufacturing method of polyimide film using the same and polyimide film prepared therefrom

The present invention relates to a polyamic acid composition having improved storage stability, a method for preparing a polyimide film using the same, and a polyimide film prepared therefrom.

Polyimide (PI) is a polymer material having 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 an imide ring.

In addition, polyimide has attracted attention as a high-performance polymer material applicable to a wide range of industrial fields such as electronics, telecommunications, and optics due to its excellent electrical properties such as insulation and low dielectric constant.

Recently, as various electronic devices become thinner, lighter and smaller, many studies have been conducted to use a thin and flexible polyimide film as a display substrate that can replace an insulating material of a circuit board or a glass substrate for a display. .

In general, a polyimide film is prepared by applying a polyamic acid produced by a polymerization reaction of dianhydride and diamine on a support and imidizing it to prepare a film, and peeling it from the support.

However, the polyamic acid contains both an amine group and a carboxylic acid group, and in particular, the hydroxy group in the carboxylic acid group can be hydrolyzed by reacting with an adjacent amine group, so that the storage stability is known to be poor. In addition, this phenomenon is known to stand out at room temperature or more than the low temperature.

If the storage stability of the polyamic acid is poor, the viscosity during the process may change significantly, and thus the application and imidization of the polyamic acid may proceed unstable. In addition, when the viscosity of the polyamic acid is lowered, the mechanical and thermal properties of the polyimide film may be greatly reduced.

The degradation of the thermal properties of the double polyimide film can be particularly negative for the manufacture of display substrates involving high temperature processes.

For example, in the case of an organic light emitting diode (OLED) using a low temperature polysilane (LTPS) process, a process temperature of 400 ° C. or higher may be formed, and even at this high temperature, even a polyimide having excellent heat resistance may be thermally decomposed. The thermal properties of the mid film may be a very important factor for implementing the display substrate.

Therefore, there is a high need for a polyamic acid having excellent storage stability at room temperature and a polyimide film having excellent mechanical and thermal properties.

It is an object of the present invention to provide a polyamic acid having excellent storage stability at room temperature, a method for producing a polyimide film having improved mechanical and thermal properties using the same, and a polyimide film.

According to one aspect of the present invention, the alcohol-based additive is disclosed as an essential factor for the implementation of the polyimide film having not only can improve the storage stability of the polyamic acid, but also has excellent thermal and mechanical properties.

The alcoholic additive may replace at least a portion of the hydroxy group included in the polyamic acid with an alkoxy group having a relatively low reactivity at room temperature.

This minimizes the phenomenon of hydrolysis of the polyamic acid at room temperature, and as a result, improves the storage stability of the polyamic acid, and also inhibits the hydrolysis even in the process of raising the temperature to imidize the polyamic acid, and includes only a hydroxyl group. It can work advantageously in the implementation of a polyimide film having excellent physical properties compared to polyamic acid.

According to another aspect of the present invention, in order to produce a polyimide film having excellent mechanical and thermal properties, a polyamic acid-containing composition in which at least a portion of a hydroxy group is substituted with an alkoxy group by an alcohol-based additive may be used.

In this case, the imidization reaction may proceed relatively quickly due to the rapid release of the alkoxy group during the heat treatment for forming the polyimide. This rapid imidization reaction may contribute to the improvement of the conversion ratio ('imidization rate') from the amic acid group to the imide group, thereby realizing a polyimide film having excellent mechanical and thermal properties.

In addition, the polyimide film prepared according to the above, the thermal decomposition temperature is 550 ℃ or more, the tensile strength is 280 kgf / cm ² or more, the thermal expansion coefficient may be 40 ppm / ℃ or less, the elongation may be 13% or more. Such a polyimide film has an advantage of satisfying the mechanical and thermal properties required for the display substrate.

Therefore, the present invention has a substantial object to provide a specific embodiment thereof.

The present invention found that the polyamic acid composition in which at least a part of the hydroxy group contained in the polyamic acid of the alcohol-based additive is substituted with an alkoxy group has excellent storage stability at room temperature.

The present invention also found that by using this to produce a polyimide film, it is possible to induce a faster imidization reaction, thereby realizing a polyimide film having excellent mechanical and thermal properties.

Thus, specific details for the implementation thereof are described herein.

Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the configuration of the embodiments described herein is only one of the most preferred embodiments of the present invention and does not represent all of the technical idea of the present invention, various equivalents and modifications that may be substituted for them at the time of the present application It should be understood that examples may exist.

As used herein, the singular forms "a", "an" and "the" include plural forms unless the context clearly indicates otherwise. As used herein, the terms "comprise", "comprise" or "have" are intended to indicate that there is a feature, number, step, component, or combination thereof, that is, one or more other features, It should be understood that it does not exclude in advance the possibility of the presence or addition of numbers, steps, components, or combinations thereof.

As used herein, "dianhydrides" are intended to include precursors or derivatives thereof, which may technically not be dianhydrides, but nevertheless will react with diamines to form polyamic acids. This polyamic acid can be converted back to polyimide.

As used herein, "diamine" is intended to include precursors or derivatives thereof, which may not technically be diamines, but will nevertheless react with dianhydrides to form polyamic acids, which in turn Can be converted to mid.

Where an amount, concentration, or other value or parameter is given herein as an enumeration of ranges, preferred ranges, or preferred upper and preferred lower values, any pair of any upper range thresholds, whether or not a range is disclosed separately, or It is to be understood that this disclosure specifically discloses all ranges formed with a desired value and any lower range limit or desired value. When a range of numerical values is mentioned herein, unless stated otherwise, the range is intended to include the endpoint and all integers and fractions within that range. It is intended that the scope of the invention not be limited to the particular values mentioned when defining the range.

제1 양태: 폴리아믹산 조성물First Embodiment: Polyamic Acid Composition

The polyamic acid composition according to the present invention comprises an organic solvent and a polyamic acid, at least a part of the hydroxy group included in the polyamic acid is alcohol-decomposed reaction with an alcohol-based additive is substituted with an alkoxy group,

The viscosity change rate according to the following formula (1) is characterized in that more than -3% to less than + 3%.

{(First viscosity-second viscosity) / first viscosity} X 100% (1)

Here, a 1st viscosity is a viscosity measured immediately after manufacture of a polyamic-acid composition, and a 2nd viscosity is the viscosity measured when 10 days passed after storing a polyamic-acid composition at normal temperature.

Since the viscosity and molecular weight of the polyamic acid are substantially proportional, the change in viscosity means that the polyamic acid has been modified, and the degree of change in viscosity can be understood as an index indicating the degree of polyamic acid modification.

In the case of a conventional polyamic acid, when stored at room temperature for about 7 days, a viscosity change rate of ± 10% or more may be exhibited, which may mean that the polyamic acid has a significant modification, and thus it may be difficult to implement a polyimide film having excellent physical properties.

On the other hand, the polyamic acid of the present invention is excellent in storage stability at room temperature because the rate of change of viscosity is not large as less than ± 3% despite storage for 10 days at room temperature. This may be due to the alkoxy group at room temperature having a relatively low room temperature reactivity compared to the hydroxy group.

The first viscosity may be 10,000 cP or less, specifically 7,500 cP or less, and more specifically 7,200 cP or less. The polyamic acid composition having such a first viscosity has an advantage of easy handling in terms of fluidity, and may be advantageous for film formation.

The polyamic acid composition may be prepared by adding at least 0.07 mol% to less than 1.5 mol% of an alcoholic additive based on 100 mol% of the amic acid group of the polyamic acid, and in detail, based on 100 mol% of the diamine monomer. , 0.1 mol% or more and 1 mol% or less.

When the polyamic acid composition is prepared by adding an alcohol-based additive to exceed the above range, it may be difficult to prepare a polyimide film having desired physical properties, and when it is below the above range, improvement in storage stability may be insignificant. , Not preferred.

The alcohol additive may be one or more selected from the group consisting of methanol, ethanol, n-propanol, isopropyl alcohol, benzyl alcohol, ethoxyethanol and butoxyethanol, but is not limited thereto.

The polyamic acid may be produced by polymerizing one or more dianhydride monomers and one or more diamine monomers in an organic solvent.

The dianhydride monomers that may be used to prepare the polyamic acid of the present invention may be aromatic tetracarboxylic dianhydrides.

The aromatic tetracarboxylic dianhydride is pyromellitic dianhydride (or PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (or BPDA), 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride (or a-BPDA), oxydiphthalic dianhydride (or ODPA), diphenylsulfone-3,4,3', 4'-tetracarboxylic Dianhydride (or DSDA), bis (3,4-dicarboxyphenyl) sulfide dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3- Hexafluoropropane dianhydride, 2,3,3 ', 4'- benzophenonetetracarboxylic dianhydride, 3,3', 4,4'-benzophenonetetracarboxylic dianhydride (or BTDA), bis (3,4-dicarboxyphenyl) methane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, p-phenylenebis (trimelitic monoester Acid Anha Idride), p-biphenylenebis (trimeric monoester acid anhydride), m-terphenyl-3,4,3 ', 4'-tetracarboxylic dianhydride, p-terphenyl- 3,4,3 ', 4'-tetracarboxylic dianhydride, 1,3-bis (3,4-dicarboxyphenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxy Phenoxy) benzene dianhydride, 1,4-bis (3,4-dicarboxyphenoxy) biphenyl dianhydride, 2,2-bis [(3,4-dicarboxy phenoxy) phenyl] propane dianone Hydride (BPADA), 2,3,6,7-naphthalenetetracarboxylic dianhydride, 1,4,5,8-naphthalenetetracarboxylic dianhydride, 4,4 '-(2,2-hexafluoro A low isopropylidene) diphthalic acid dianhydride etc. are mentioned. These may be used alone or in combination of two or more as desired, but dianhydride monomers which may be particularly preferably used in the present invention are 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 (a-BPDA) Can be.

Diamine monomers that can be used in the production of the polyamic acid of the present invention are aromatic diamines, and are classified as follows.

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

2) diaminodiphenyl ethers such as 4,4'-diaminodiphenyl ether (or oxydianiline, ODA), 3,4'-diaminodiphenyl ether, and 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, 3,3' -Dichlorobenzidine, 3,3'-dimethylbenzidine (or o-tolidine), 2,2'-dimethylbenzidine (or m-tolidine), 3,3'-dimethoxybenzidine, 2,2'-dimethoxy Benzidine, 3,3'-diaminodiphenylether, 3,4'-diaminodiphenylether, 4,4'-diaminodiphenylether, 3,3'-diaminodiphenylsulfide, 3,4 ' -Diaminodiphenylsulfide, 4,4'-diamino Phenylsulfide, 3,3'-diaminodiphenylsulfone, 3,4'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 4,4 ' -Diaminobenzophenone, 3,3'-diamino-4,4'-dichlorobenzophenone, 3,3'-diamino-4,4'-dimethoxybenzophenone, 3,3'-diaminodiphenyl Methane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 2,2-bis (3-aminophenyl) propane, 2,2-bis (4-amino Phenyl) 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'-diaminodiphenylsulfoxide, 4,4'-diaminodiphenylsulfoxide Diamines having two benzene nuclei in structure, and the like;

3) 1,3-bis (3-aminophenyl) benzene, 1,3-bis (4-aminophenyl) benzene, 1,4-bis (3-aminophenyl) benzene, 1,4-bis (4-amino Phenyl) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene (or TPE-Q), 1,4-bis (4-aminophenoxy) Benzene (or TPE-Q), 1,3-bis (3-aminophenoxy) -4-trifluoromethylbenzene, 3,3'-diamino-4- (4-phenyl) phenoxybenzophenone, 3 , 3'-diamino-4,4'-di (4-phenylphenoxy) benzophenone, 1,3-bis (3-aminophenylsulfide) benzene, 1,3-bis (4-aminophenylsulfide) Benzene, 1,4-bis (4-aminophenylsulfide) benzene, 1,3-bis (3-aminophenylsulfone) benzene, 1,3-bis (4-aminophenylsulfone) benzene, 1,4-bis ( 4-aminophenylsulfone) benzene, 1,3-bis [2- (4-aminophenyl) isopropyl] benzene, 1,4-bis [2- (3-aminophenyl) isopropyl] benzene, 1,4- Having three benzene nuclei in structure, such as bis [2- (4-aminophenyl) isopropyl] benzene Amine;

4) 3,3'-bis (3-aminophenoxy) biphenyl, 3,3'-bis (4-aminophenoxy) biphenyl, 4,4'-bis (3-aminophenoxy) biphenyl, 4,4'-bis (4-aminophenoxy) biphenyl, bis [3- (3-aminophenoxy) phenyl] ether, bis [3- (4-aminophenoxy) phenyl] ether, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, bis [3- (3-aminophenoxy) phenyl] ketone, bis [3- (4-aminophenoxy C) phenyl] ketone, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-amino phenoxy) phenyl] ketone, bis [3- (3-aminophenoxy) phenyl] sulfide , Bis [3- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [3- (3-aminophenoxy) phenyl] sulfone, bis [3- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-ami) Phenoxy) phenyl] sulfone, bis [3- (3-aminophenoxy) phenyl] methane, bis [3- (4-aminophenoxy) phenyl] methane, bis [4- (3-aminophenoxy) Phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane, 2,2-bis [3- (3-aminophenoxy) phenyl] propane, 2,2-bis [3- ( 4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP), 2,2-bis [3- (3-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [3- (4 -Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (3-aminophenoxy) phenyl] -1,1,1, Such as 3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, and the like, Diamine with four benzene nuclei in structure.

These may be used alone or in combination of two or more as desired, but the diamine monomers which may be particularly preferably used in the present invention include 1,4-diaminobenzene (PPD) and 1,3-diaminobenzene (MPD). ), 2,4-diaminotoluene, 2,6-diaminotoluene, and 3,5-diaminobenzoic acid (DABA).

In the polyamic acid composition, the diamine monomer and the dianhydride monomer may be added in substantially equimolar, and in detail, based on 100 mol% of the diamine monomer, the amount of the dianhydride monomer added is 99 mol% to 101. The amount of the dianhydride monomer may be 99 mol% to 99.9 mol% based on 100 mol% of the diamine monomer.

When the input amount of the dianhydride monomer is above or below the above range, the polymerization is terminated before reaching a desired molecular weight, or a plurality of low molecular weight oligomers are generated to implement a polyamic acid capable of forming a polyimide film. it's difficult.

제2 양태: 폴리이미드 필름의 제조방법 및 폴리이미드 필름Second Embodiment: Production Method of Polyimide Film and Polyimide Film

The manufacturing method of the polyimide film which concerns on this invention,

(a) preparing a polyamic acid solution containing polyamic acid by adding one or more dianhydride monomers and one or more diamine monomers to an organic solvent and polymerizing them;

(b) preparing a polyamic acid composition by adding at least 0.07 mol% to less than 1.5 mol% of an alcoholic additive based on 100 mol% of the amic acid group of the polyamic acid to the polyamic acid solution; And

(c) drying the polyamic acid composition to form a gel film;

(d) heat treating the gel film to obtain a polyimide film.

Advantages of the manufacturing method according to the invention,

In the step (b), at least a part of the hydroxy group included in the polyamic acid is reacted with the alcoholic additive to be substituted with an alkoxy group;

In the above steps (c) and (d), the hydroxy group and the alkoxy group may each react with the amine group to form a plurality of imide groups, wherein the alkoxy group serves as a good leaving group, This is the point where the reaction can be promoted.

In summary, the alkoxy group is less reactive than a hydroxy group at room temperature, and thus is preferable for polyamic acid in terms of storage stability.At high temperature for polyimide film production, the alkoxy group can act as an excellent leaving group to promote the imidization reaction of polyamic acid, It can serve as a significant advantage for both mymic acid and polyimide films. In addition, a polyimide film having a high imidation ratio can be realized from these advantages.

Since the high imidation ratio is a major factor causing the polyimide film to express excellent thermal and mechanical properties, the advantages of the production method of the present invention can be sufficiently expected.

Preparation of the polyamic acid solution in the present invention is, for example,

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

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

(3) After putting some components of the diamine monomer in the solvent, and then mixed some components of the dianhydride monomer in the ratio of about 95 to 105 mol% with respect to the reaction component, the remaining diamine monomer component is added and the rest Adding a dianhydride monomer component so that the diamine monomer and the dianhydride monomer are substantially equimolar and polymerized;

(4) After putting a dianhydride monomer in a solvent, after mixing some components of a diamine compound in the ratio of 95-105 mol% with respect to a reaction component, another dianhydride monomer component is added and it continues, and the remaining diamine monomer component is carried out. Adding a diamine monomer and a dianhydride monomer to substantially equimolar polymerization;

(5) Some diamine monomer component and some dianhydride monomer component are reacted to an excess in one solvent to form a first composition, and some diamine monomer component and some dianhydride monomer component are dissolved in another solvent. A method of reacting an excess of one to form a second composition, then mixing the first and second compositions and completing the polymerization, wherein if the diamine monomer component is excessive when forming the first composition, In the second composition, when the dianhydride monomer component is in excess and the dianhydride monomer component in the first composition is in excess, in the second composition, the diamine monomer component is in excess, and the first and second compositions are mixed and reacted. So that the total diamine monomer component and dianhydride monomer component used in the And the like over the polymerization method.

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

The dianhydride monomer may be appropriately selected from the examples described above, and specifically, pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride ( s-BPDA) and 2,3,3 ', 4'-biphenyltetracarboxylic dianhydride (a-BPDA) may be preferably used.

The dianhydride monomer may be appropriately selected from the examples described above, and specifically, 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, At least one selected from the group consisting of 2,6-diaminotoluene and 3,5-diaminobenzoic acid (DABA) can be preferably used.

The alcoholic additive may be at least one selected from the group consisting of methanol, ethanol, n-propanol, isopropyl alcohol, benzyl alcohol, ethoxyethanol and butoxyethanol, but the scope of the present invention is not limited thereto. .

Based on 100 mol% of the diamine monomer, the amount of the dianhydride monomer may be 99 mol% to 99.9 mol%, and the amount of the alcohol-based additive may be 0.1 mol% to 1 mol%.

When the amount of the dianhydride monomer is above or below the above range, the polymerization is terminated before the desired molecular weight is reached, or a plurality of low molecular weight oligomers are generated to form a polyimide film with the polyamic acid prepared therefrom. Problems you can't do can happen.

When the alcohol-based additive is added in the above range, it may be difficult to manufacture a polyimide film having the desired physical properties, if the alcohol-based additive is below the range, the improvement of the storage stability of the polyamic acid solution may be insignificant, Not desirable

In the manufacturing method of the present invention, the polyimide film may be prepared through thermal imidization. The said thermal imidation method is a method of removing an chemical catalyst and inducing an imidation reaction with heat sources, such as a hot air and an infrared dryer.

For reference, in the step (b) in which the alkoxylation reaction occurs by introducing an alcoholic additive, at least a part of the added alcoholic additive may remain unreacted, and water is generated as a by-product of the alkoxylation reaction. May remain in the acid solution. Water remaining in the polyamic acid solution may lose the function of the anhydride catalyst used as the chemical catalyst in the imidization process. Therefore, even if a chemical catalyst is used, there is a possibility that the imidization reaction does not proceed effectively. Thus, the thermal imidation method without using the chemical catalyst may be preferable for the implementation of the polyimide film intended in the present invention.

The thermal imidization method may include the step (d), wherein the gel film is heat-treated at a variable temperature ranging from 50 ° C. to 600 ° C. in the step (d) to present an amic acid group present in the gel film. It can imidize.

However, some of the amic acid (about 0.1 mol% to 10 mol%) may be imidized in the process (c) of forming the gel film, and for this purpose, in the process (c), the range of 50 ° C. to 200 ° C. It is possible to dry the polyamic acid composition at variable temperatures, which may also fall within the scope of the thermal imidization method.

The polyimide film of the present invention prepared according to the above production method, the thermal decomposition temperature (Td) is 550 ℃ or more, the thermal expansion coefficient is 40 ppm / ℃ or less, elongation is 13% or more, tensile strength 280 kgf / cm ^{2 or} more.

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

Hereinafter, the operation and effects of the invention will be described in more detail with reference to specific examples of the invention. However, these embodiments are only presented as an example of the invention, whereby the scope of the invention is not determined.

The compound names of the abbreviations used in the Examples and Comparative Examples are as follows.

Biphenyltetracarboxylic dianhydride: BPDA

-Pyromellitic dianhydride: PMDA

1,4-diaminobenzene: PPD

N-methyl pyrrolidone: NMP

824 g of NMP was added to a 1000 ml reactor equipped with a stirrer and a nitrogen inlet / outlet tube, and the reactor temperature was set to 35 ° C., followed by 40.5 g of PPD and 101.4 g of BPDA to completely dissolve and react. Stir until. After the reaction was completed, 2.85 g of BPDA was dissolved in NMP at 10% by weight, and then added at 10 minutes intervals until the viscosity at 23 ° C. reached 8000 cP. Thereafter, the temperature of the reactor was set to 50 ° C., and 0.1 mol of methanol was added to 100 mol of PPD. After sufficient stirring until the reaction was completed, a polyimide precursor composition (viscosity at 23 ° C .: 7,100 cP) was prepared.

Viscosity was measured by measuring Brookfield viscometer (RVDV-II + P) twice at 50 rpm using 7 scandals at 25 ° C.

Except for changing the molar ratio of BPDA and methanol as shown in Table 1 below, a polyamic acid composition was prepared in the same manner as in Example 1 and the first viscosity was measured. The measured viscosity was about 6,900 cP.

Except for adding ethanol in the molar ratio shown in Table 1 instead of methanol, a polyamic acid composition was prepared in the same manner as in Example 1 and the first viscosity was measured. The measured viscosity was 6,970 cP.

A polyamic acid composition was prepared in the same manner as in Example 1 except that n-propanol was added in the molar ratio shown in Table 1 instead of methanol, and the first viscosity was measured. The measured viscosity was 6,950 cP.

Example 5

PPD, BPDA and PMDA were added to NMP in a molar ratio shown in Table 1 while maintaining the reaction system at 25 ° C. to prepare a polyamic acid solution. Methanol was added to the polyamic acid solution thus prepared in the molar ratio shown in Table 1 to prepare a polyamic acid composition, and the first viscosity was measured. The measured viscosity was about 5,300 cP.

Except for changing the molar ratio of BPDA and methanol as shown in Table 1 below, a polyamic acid composition was prepared in the same manner as in Example 5 and the first viscosity was measured. The measured viscosity was about 5,150 cP.

Comparative Example 1

PPD and BPDA were added to NMP in a molar ratio shown in Table 1 while maintaining the inside of the reaction system at 25 ° C to polymerize to prepare a polyamic acid solution, and the first viscosity was measured. The measured viscosity was about 7,100 cP.

Comparative Example 2

Except for changing the molar ratio of BPDA and methanol as shown in Table 1 below, a polyamic acid composition was prepared in the same manner as in Example 1 and the first viscosity was measured. The measured viscosity was about 6,780 cP.

Comparative Example 3

Except for changing the molar ratio of BPDA and methanol as shown in Table 1 below, a polyamic acid composition was prepared in the same manner as in Example 1 and the viscosity was measured. The viscosity measured was about 6,950 cP.

Ethanol was used instead of methanol, except for changing the molar ratio of BPDA and ethanol as shown in Table 1 below, a polyamic acid composition was prepared in the same manner as in Example 1, and the first viscosity was measured. The measured viscosity was 7,050 cP.

Comparative Example 5

N-propanol was used instead of methanol, and the polyamic acid composition was prepared in the same manner as in Example 1 except that the molar ratio of BPDA and n-propanol was changed as shown in Table 1 below, and the first viscosity was measured. The measured viscosity was 7,000 cP.

Comparative Example 6

Except for changing the molar ratio of BPDA and methanol as shown in Table 1 below, a polyamic acid composition was prepared in the same manner as in Example 5 and the viscosity was measured. The measured viscosity was about 5,400 cP.

Comparative Example 7

Except for changing the molar ratio of BPDA and methanol as shown in Table 1 below, a polyamic acid composition was prepared in the same manner as in Example 5 and the viscosity was measured. The measured viscosity was about 5,010 cP.

	PPD(몰%)PPD (mol%)	PMDA(몰%)PMDA (mol%)	BPDA(몰%)BPDA (mol%)	메탄올(몰%)Methanol (mol%)	에탄올(몰%)Ethanol (mol%)	n-프로판올(몰%)n-propanol (mol%)	제1 점도(cP)First viscosity (cP)
실시예 1Example 1	100100	--	99.999.9	0.10.1	--	--	7,1007,100
실시예 2Example 2	100100	--	9999	1One	--	--	6,9006,900
실시예 3Example 3	100100	--	99.999.9	--	0.10.1	--	6,9706,970
실시예 4Example 4	100100	--	99.999.9	--	--	0.10.1	6,9506,950
실시예 5Example 5	100100	5050	49.949.9	0.10.1	--	--	5,3005,300
실시예 6Example 6	100100	5050	4949	1One	--	--	5,1505,150
비교예 1Comparative Example 1	100100	--	100100	--	--	--	7,1007,100
비교예 2Comparative Example 2	100100	--	98.598.5	1.51.5	--	--	6,7806,780
비교예 3Comparative Example 3	100100	--	99.9599.95	0.050.05	--	--	6,9506,950
비교예 4Comparative Example 4	100100	--	99.9599.95	--	0.050.05	--	7,0507,050
비교예 5Comparative Example 5	100100	--	99.9599.95	--	--	0.050.05	7,0007,000
비교예 6Comparative Example 6	100100	5050	49.9549.95	0.050.05	--	--	5,4005,400
비교예 7Comparative Example 7	100100	5050	48.548.5	1.51.5	--	--	5,0105,010

Experimental Example 1: Evaluation of Storage Stability

The polyamic acid composition prepared in Examples 1 to 6 and Comparative Examples 1 to 7 was left at room temperature for 10 days. Thereafter, the second viscosity was measured by the viscosity measuring method described in Example 1, and the viscosity change rate was calculated according to the following formula (1) and shown in Table 2 below.

{(First viscosity-second viscosity) / first viscosity} X 100% (1)

	제1 점도(cP)First viscosity (cP)	제2 점도(cP)Second viscosity (cP)	점도 변화율(%)% Viscosity change
실시예 1Example 1	7,1007,100	7,2107,210	+1.55%+ 1.55%
실시예 2Example 2	6,9006,900	7,0707,070	+2.46%+ 2.46%
실시예 3Example 3	6,9706,970	7,1007,100	+1.86%+ 1.86%
실시예 4Example 4	6,9506,950	7,1007,100	+2.16%+ 2.16%
실시예 5Example 5	5,1505,150	5,2505,250	+1.32%+ 1.32%
실시예 6Example 6	5,3005,300	5,4205,420	+2.26%+ 2.26%
비교예 1Comparative Example 1	7,1007,100	8,0308,030	+13.10%+ 13.10%
비교예 2Comparative Example 2	6,7806,780	6,1206,120	-10.78%-10.78%
비교예 3Comparative Example 3	6,9506,950	7,6707,670	+10.36%+ 10.36%
비교예 4Comparative Example 4	7,0507,050	7,8507,850	+11.35%+ 11.35%
비교예 5Comparative Example 5	7,0007,000	7,8907,890	+12.71%+ 12.71%
비교예 6Comparative Example 6	5,4005,400	6,0306,030	+11.67%+ 11.67%
비교예 7Comparative Example 7	5,0105,010	4,5204,520	-10.84%-10.84%

As shown in Table 2, the viscosity of the polyamic acid composition of Examples 1 to 6 in which the alcoholic additive was added within the range of the present invention did not change significantly even after 10 days had elapsed.

From the above result, it turns out that the polyamic-acid composition of this invention is excellent in storage stability at normal temperature.

This means that an appropriate amount of alcohol-based additives within the scope of the present invention substituted at least a portion of the hydroxy group capable of inducing a modification reaction such as hydrolysis at room temperature with an alkoxy group. It is assumed that this is due to no reaction.

On the other hand, in Comparative Example 1, in which no alcohol-based additive was added, a marked decrease in viscosity of the polyamic acid was caused. It is expected that the hydroxyl group in the polyamic acid of Comparative Example 1 promotes a modification reaction such as hydrolysis, and accordingly, the viscosity greatly changes as shown in Table 2.

On the other hand, in the case of Comparative Examples 2 to 7, despite the addition of alcohol-based additives, a large viscosity change was involved. This clearly shows that the use of too little or too much alcoholic additives outside the scope of the present invention does not produce an improvement in storage stability.

The polyimide precursor composition of Example 1 was bubbled through a high speed rotation of at least 1,500 rpm. Thereafter, the degassed polyimide precursor composition was applied to the glass substrate using a spin coater. After drying in a nitrogen atmosphere and at a temperature of 120 ℃ for 30 minutes, the temperature was raised to 450 ℃ at a rate of 2 ℃ / min, heat treatment at 450 ℃ for 60 minutes, cooled to 30 ℃ at a rate of 2 ℃ / min A polyimide film was prepared. After dipping in distilled water, the polyimide film was peeled off the glass substrate. The thickness of the produced polyimide film was 15.1 μm.

The thickness of the prepared polyimide film was measured using an Anritsu Electric Film thickness tester.

A polyimide film having a thickness of 15 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Example 2 was used.

Example 9

A polyimide film having a thickness of 15.5 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Example 3 was used.

A polyimide film having a thickness of 15.4 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Example 4 was used.

A polyimide film having a thickness of 14.8 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Example 5 was used.

A polyimide film having a thickness of 14.6 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Example 6 was used.

A polyimide film having a thickness of 15.3 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Comparative Example 1 was used.

Comparative Example 9

A polyimide film having a thickness of 15.7 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Comparative Example 2 was used.

Comparative Example 10

A polyimide film having a thickness of 15.5 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Comparative Example 3 was used.

Comparative Example 11

A polyimide film having a thickness of 15.5 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Comparative Example 4 was used.

Comparative Example 12

A polyimide film having a thickness of 15.4 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Comparative Example 5 was used.

Comparative Example 13

A polyimide film having a thickness of 15.3 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Comparative Example 6 was used.

Comparative Example 14

A polyimide film having a thickness of 15 μm was obtained in the same manner as in Example 7, except that the polyamic acid composition of Comparative Example 7 was used.

Experimental Example 2: Physical Property Evaluation

The physical properties of the polyimide films prepared in Examples 7 to 10 and Comparative Examples 8 to 12 were measured using the following methods, and the results are shown in Table 3 below.

(1) pyrolysis temperature

Pyrolysis temperature was measured using a Perkin Elmer TGA measuring device. The polyimide film was cut into 3 mm x 3 mm, placed on a pre-treated and weighed fan, insulated at 110 ° C. for 30 minutes, cooled to room temperature, and heated again at 600 ° C. per 5 ° C. to reduce the weight. Was measured. The pyrolysis temperature was calculated when the weight loss ratio was 1% of the weight of the polyimide film initially loaded.

(2) tensile strength

Tensile strength was measured by the method according to KS6518.

(3) thermal expansion coefficient (CTE)

The TA company thermomechanical analyzer Q400 model was used, and the polyimide film was cut into a width of 2 mm and a length of 10 mm, and then subjected to a tension of 0.05 N in a nitrogen atmosphere at 500 ° C. After the temperature was raised to ℃ and cooled again at a rate of 10 ℃ / min was measured the slope of 100 ℃ 400 ℃ section.

	열분해온도(℃)Pyrolysis Temperature (℃)	인장강도(kgf/cm²)Tensile strength (kgf / cm ² )	CTE(ppm/℃)CTE (ppm / ° C)
실시예 7Example 7	564564	372372	4.54.5
실시예 8Example 8	564564	375375	5.65.6
실시예 9Example 9	563563	353353	7.27.2
실시예 10Example 10	563563	360360	3.33.3
비교예 8Comparative Example 8	554554	278278	33.433.4
비교예 9Comparative Example 9	538538	--	--
비교예 10Comparative Example 10	545545	248248	22.822.8
비교예 11Comparative Example 11	543543	253253	24.724.7
비교예 12Comparative Example 12	543543	255255	26.926.9

With regard to the above results, attention should be paid to Example 7 and Comparative Example 8 in which the monomer composition is similar.

The polyimide film of Example 7 was prepared from the polyamic acid composition in which the alcohol-based additive was added to the polyamic acid, and it can be seen that the polyimide film has a relatively excellent thermal decomposition temperature and tensile strength.

On the other hand, the polyimide film of Comparative Example 8 was prepared from a polyamic acid without an alcohol-based additive, it can be seen that it has a significantly lower thermal decomposition temperature and tensile strength than Example 7.

In general, at a high temperature formed to form a polyimide, among the alkoxy and hydroxy groups, the alkoxy group may react at a faster reaction rate with an adjacent amine group. This is expected to be due to the alkoxy group belonging to a relatively better leaving group compared to the hydroxy group at the temperature formulated for imidization.

Therefore, it was expected that when the same time imidization was performed, the polyamic acid composition containing the alkoxy group could be converted into a polyimide film having a higher imidation ratio, and according to the comparatively excellent thermal in Example 7, On the other hand, the mechanical properties are shown, but in Comparative Example 8, which does not correspond to this, it is assumed that relatively poor thermal and mechanical properties were shown.

Likewise, when comparing Examples 8, 9, 10 and Comparative Examples 8, 10, 11, 12 with similar monomer compositions, better thermal decomposition temperatures and tensile strengths were found in all of the examples, which is further described above. Prove it clearly.

Also noteworthy is the coefficient of thermal expansion measured in Examples and Comparative Examples.

The thermal expansion coefficient of the polyimide film may be preferably 15 ppm / ° C., specifically 10 ppm / ° C. or less, in terms of dimensional stability at high temperature. It is important that the dimension does not change even at a high temperature process of more than ℃, it may be desirable to have a thermal expansion coefficient of 10 ppm / ℃ or less.

Therefore, in the case of the embodiment falling within the scope of the present invention, the thermal expansion coefficient of 8 ppm / ℃ or less, it can be seen that the dimensional stability at high temperature, such characteristics are required in various electronic fields, such as display substrates or flexible circuits It can be used preferably.

On the other hand, in the comparative example, the coefficient of thermal expansion was remarkably high, which can be expected to be difficult to apply to the above-described electronic field due to poor dimensional stability at high temperature.

On the other hand, the polyimide film of Comparative Example 9, although in the form of a film, exhibited brittle characteristics and thus could not measure tensile strength.

This suggests that the use of excessive alcohol-based additives outside the scope of the present invention can significantly deteriorate the physical properties of the polyimide film.

Experimental Example 3: Evaluation of Film Appearance

The appearance of the polyimide films prepared in Examples 11 and 12 and Comparative Examples 13 and 14 was visually observed, and it was determined whether or not it could be used commercially, and the results are shown in Table 4.

For example, when the film is a good product, it is represented as 'O', and it is represented as 'X' when it is judged to be defective because it has no self-supporting or brittle characteristics.

	외형 평가Appearance evaluation
실시예 11Example 11	OO
실시예 12Example 12	OO
비교예 13Comparative Example 13	XX
비교예 14Comparative Example 14	XX

From the results in Table 4, it can be seen that polyimide films are not produced in good condition when excessive or too little alcoholic additive is used outside the scope of the present invention.

Although described above with reference to embodiments of the present invention, those skilled in the art will be able to perform various applications and modifications within the scope of the present invention based on the above contents.

A feature of the polyamic acid composition according to the present invention is that at least a part of the hydroxy group included in the polyamic acid is substituted with an alkoxy group by adding an alcoholic additive. The alkoxy group has a relatively low reactivity at room temperature and does not cause denaturation of the polyamic acid. Accordingly, the polyamic acid composition has an advantage of improving room temperature storage stability. The alkoxy group can also inhibit hydrolysis even in the process of raising the temperature to imidize the polyamic acid, which can advantageously act to implement a polyimide film having better physical properties than in the absence of the alkoxy group.

Advantages of the production method according to the present invention, by using an polyimide composition in which an alcohol-based additive is added to the polyamic acid to replace at least part of the hydroxy group with an alkoxy group, a polyimide film having excellent mechanical and thermal properties can be produced. will be.

This, as the imidation reaction proceeds relatively fast due to the rapid release of the alkoxy group during the heat treatment for producing the polyimide film, it may be due to the improved imidation rate.

In addition, the polyimide film prepared according to the above, the thermal decomposition temperature is 550 ℃ or more, the tensile strength is 280 kgf / cm ² or more, it can have excellent thermal and mechanical properties required for the display substrate.

Claims

Organic solvents and polyamic acid,

At least a part of the hydroxyl group included in the polyamic acid is alcohol-decomposed with an alcohol-based additive and substituted with an alkoxy group,

A polyamic acid composition, wherein the rate of change of viscosity according to formula (1) is greater than -3% and less than + 3%:

{(First viscosity-second viscosity) / first viscosity} X 100% (1)

Here, a 1st viscosity is a viscosity measured immediately after manufacture of a polyamic-acid composition, and a 2nd viscosity is the viscosity measured when 10 days passed after storing a polyamic-acid composition at normal temperature.
The method of claim 1,

A polyamic acid composition prepared by adding at least 0.07 mol% to less than 1.5 mol% of an alcoholic additive based on 100 mol% of the amic acid group of the polyamic acid.
The method of claim 1,

The polyamic acid composition, wherein the alcohol additive is at least one selected from the group consisting of methanol, ethanol, n-propanol, isopropyl alcohol, benzyl alcohol, ethoxyethanol and butoxyethanol.
The method of claim 1,

The polyamic acid is produced by polymerizing at least one dianhydride monomer and at least one diamine monomer in an organic solvent,

Based on 100 mol% of the diamine monomer, the input amount of the dianhydride monomer is 99 mol% to 99.9 mol%, the input amount of the alcohol-based additive is 0.1 mol% to 1 mol%, polyamic acid composition.
The method of claim 4, wherein

The dianhydride monomers are pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) and 2,3,3', 4 ' A polyamic acid composition, which is at least one member selected from the group consisting of -biphenyltetracarboxylic dianhydride (a-BPDA).
The method of claim 4, wherein

The diamine monomers are 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene and 3,5-diaminobenzoic acid At least one selected from the group consisting of acid (DABA), polyamic acid composition.
The method of claim 1,

The polyamic acid composition having a first viscosity of 10,000 cP or less.
As a method of manufacturing a polyimide film,

(a) preparing a polyamic acid solution containing polyamic acid by adding one or more dianhydride monomers and one or more diamine monomers to an organic solvent and polymerizing them;

(b) preparing a polyamic acid composition by adding at least 0.07 mol% to less than 1.5 mol% of an alcoholic additive based on 100 mol% of the amic acid group of the polyamic acid to the polyamic acid solution; And

(c) drying the polyamic acid composition to form a gel film;

(d) heat treating the gel film to obtain a polyimide film.
The method of claim 8,

In the step (b), at least a part of the hydroxy group included in the polyamic acid is reacted with the alcoholic additive to be substituted with an alkoxy group;

In step (c) and step (d), the hydroxyl group and the alkoxy group, respectively, react with an amine group to form a plurality of imide groups.
The method of claim 8,

Based on 100 mole% of the diamine monomer, the amount of the dianhydride monomer added is 99 mol% to 99.9 mol%, and the amount of the alcohol-based additive is 0.1 mol% to 1 mol%.
The method of claim 8,

The dianhydride monomers are pyromellitic dianhydride (PMDA), 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) and 2,3,3', 4 ' -At least one member selected from the group consisting of biphenyltetracarboxylic dianhydride (a-BPDA),

The diamine monomers are 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6-diaminotoluene and 3,5-diaminobenzoic acid At least one selected from the group consisting of acid (DABA), the production method.
The method of claim 8,

The alcohol-based additive is one or more selected from the group consisting of methanol, ethanol, n-propanol, isopropyl alcohol, benzyl alcohol, ethoxyethanol and butoxyethanol.
The method of claim 8,

The polyimide film is prepared through the thermal imidization method,

In the process (c) is dried at a variable temperature in the range of 50 ℃ to 200 ℃,

Heat treatment at a variable temperature in the range of 50 ℃ to 600 ℃ in the process (d).
A polyimide film produced by the manufacturing method according to claim 8,

Pyrolysis temperature (Td) is 550 ℃ or more,

The coefficient of thermal expansion is 40 ppm / ° C or less,

Elongation is over 13%,

A polyimide film having a tensile strength of at least 280 kgf / cm 2 .
An electronic device comprising the polyimide film of claim 14.
The electronic device of claim 15, wherein the electronic device comprises a flexible printed circuit board or a display substrate.