KR101259544B1 - Polyimide film - Google Patents

Abstract

More particularly, the present invention relates to a polyimide film obtained by adding s-BPDA and PMDA after dissolving p-phenylenediamine (p-PDA), wherein the mixing ratio of the p-PDA, s- Are mixed in a molar ratio of 4: 1: 3 to 6: 1: 5 to obtain a polyimide film.

Description

Polyimide film [0002]

TECHNICAL FIELD The present invention relates to a polyimide film, and more particularly, to a polyimide film having excellent thermal stability utilized for a flexible circuit board and the like.

Polyimide resin is an insoluble and non-fusible super high heat resistant resin. It has excellent properties such as heat resistance, oxidation resistance, heat resistance, radiation resistance, low temperature property and chemical resistance. It is a high heat resistant material such as automobile material, Coatings, insulating films, semiconductors, and electronic materials such as electrode protection films for TFT-LCDs.

Generally, a polyimide resin is a high heat-resistant resin prepared by preparing a polyamic acid derivative by the conjugation polymerization of an aromatic dianhydride and an aromatic diamine, dehydrating it by cyclization at a high temperature, and imidizing it.

As a method for producing a polyimide film, there is a cast method in which a polyamic acid derivative, which is a polyimide precursor, is applied to a carrier plate and cured to obtain a polyimide film. The casting method comprises a step of applying the resin solution to the carrier plate, a drying step of removing the solvent in the resin, and an imidization step of converting the polyimide precursor resin into polyimide.

However, the imidization process for converting polyimide into polyimide is performed at a high temperature, but when the temperature is changed at a high temperature, the polyimide is swollen due to the characteristics of the film.

Further, in using a polyimide film as a substrate of a display device, it is necessary to have excellent thermal stability in a high-temperature process of 500 ° C or more. Generally, glass used as a substrate of a display device has excellent thermal stability at a high temperature, and a film that can replace a glass should have excellent thermal stability in a high temperature process of 500 ° C or higher.

However, since the conventional polyimide film is not excellent in thermal stability, it has been desired to develop a polyimide film having a small thermal expansion degree and excellent thermal stability as the degree of thermal expansion at a high temperature increases.

It is an object of the present invention to provide a polyimide film excellent in thermal stability even in a high temperature process.

In order to achieve the above object, the present invention is achieved by adding PMDA and s-BPDA after dissolving p-phenylenediamine (p-PDA), wherein the mixing ratio of the p-PDA, PMDA and s- : 3 to 6: 1: 5.

The present invention also provides a polyimide film characterized in that a condensation reaction takes place at a molar ratio of aromatic diamine of p-PDA with aromatic dianhydride of PMDA and s-BPDA in a 1: 1 molar ratio.

The present invention also relates to a process for the production of a p-phenylenediamine (p-PDA), which comprises dissolving p-PDE in a solvent selected from the group consisting of N-methyl-2-pyrrolidone (NMP), N, N'-dimethylformamide and N, N'-dimethylacetamide 1 or more of the polyimide film is selected.

Also, the present invention relates to a thermosetting resin composition having p-PDA, PMDA and s-BPDA mixed at a molar ratio of 4: 1: 3 to 6: 1: 5 and having a thermal expansion coefficient of -7 to -6.1 ppm / And a polyimide film.

Also, the present invention relates to a process for producing a p-PDA, PMDA and s-BPDA mixed at a molar ratio of 4: 1: 3 to 6: 1: 5 and having a thermal expansion coefficient of -4.9 to -3.5 ppm / And a polyimide film.

The polyimide film according to the present invention provides an optimized composition of reactants for obtaining polyimides having excellent thermal properties by condensation polymerization of aromatic diamines and aromatic dianhydrides.

In addition, the polyimide film according to the present invention has excellent thermal stability at a high temperature and can be usefully used as a substrate of a display device to be performed in a high-temperature process.

Hereinafter, the present invention will be described in detail. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

The terms "about "," substantially ", etc. used to the extent that they are used herein are intended to be taken to mean an approximation of, or approximation to, the numerical values of manufacturing and material tolerances inherent in the meanings mentioned, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

The present invention relates to a process for the preparation of p-phenylenediamine (p-PDA) by dissolving pyromellitic dianhydride (PMDA) and s-biphenyl tetracarboxylic dianhydride (s-BPDA ), And the mixing ratio of the p-PDA, PMDA and s-BPDA is 4: 1: 3 to 6: 1: 5.

A process for producing a polyimide film according to an embodiment of the present invention will now be described.

First, p-phenylenediamine among the aromatic diamines is prepared and dissolved in an organic solvent.

The structural formula of p-phenylenediamine (p-PDA) in aromatic diamines is as follows.

In this case, it is preferable that aprotic solvent is used as an amide solvent in general, and a polar solvent is preferably used as an amide solvent as a preferable organic solvent. N-methyl-2- N, N'-dimethylformamide, N, N'-dimethylacetamide, etc. may be used. If necessary, two or more of them may be used in combination.

After the p-phenylenediamine is completely dissolved in the solvent, an aromatic dianhydride material is added. Preferred aromatic dianhydride materials are pyromellitic dianhydride (PMDA) and s-biphenyltetracarboxylic acid S-biphenyl tetracarboxylic dianhydride (s-BPDA).

The structural formulas of pyromellitic dianhydride (PMDA) and s-biphenyl tetracarboxylic dianhydride (s-BPDA) are shown below.

[Pyromellitic dianhydride (PMDA)]

[s-biphenyl tetracarboxylic dianhydride (s-BPDA)]

The reaction temperature at which p-PDA, PMDA and s-BPDA react is preferably 10 ° C., and the added PMDA and s-biphenyltetracarboxylic dianhydride (s-BPDA) are aromatic dianhydrides The polyamic acid solution can be obtained by adding it.

The mixing ratio of the p-PDA, PMDA and s-BPDA is preferably in a molar ratio of 4: 1: 3 to 6: 1: 5.

When mixed in the above range, the thermal expansion coefficient has a negative value. As the temperature increases, the polyimide film produced tends to shrink.

The mixed p-PDA, PMDA and s-BPDA were stirred for about 3 hours, and a polyamic acid solution was added so that a condensation reaction was carried out with aromatic dianhydride of p-PDA and aromatic dianhydride of PMDA and s-BPDA in a 1: 1 molar ratio .

The polyamic acid solution obtained after the completion of the reaction may be formed on a film coated on a support and gelled by dry air or hot air. As the support, a glass plate, an aluminum foil, a stainless belt, or the like can be used, but the present invention is not limited thereto. The gelation temperature condition of the film applied to the support is preferably 100 to 250 ° C, and the treatment time is preferably 30 to 60 minutes.

The gelled film is separated from the support and dried and imidized to complete the polyimide film.

The imidization temperature condition of the gelled film is preferably 80 to 400 ° C, and the treatment time is preferably 1 to 10 hours.

The polyimide film produced by the above method has rigidity due to the linearity of the main chain of the polyimide, and the molecular mobility of the polyimide is weakened, so that the coefficient of thermal expansion (CTE) has a minus value.

The polyimide film produced by the present invention has a coefficient of thermal expansion (CTE) of -7 to -6.1 ppm / 占 폚 at 50 to 300 占 폚.

The polyimide film produced by the present invention has a thermal expansion coefficient of from -4.9 to -3.5 ppm / ° C at 50 to 500 ° C.

Hereinafter, embodiments of the present invention will be described in detail.

Example  One

The reactor was charged with 461 ml of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 1 L reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser. Thereafter, p-phenylenediamine (p-PDA) was used as an aromatic diamine, and 32.4 g (0.30 mol) of the p-phenylenediamine was added thereto to completely dissolve the compound. Thereafter, 13.09 g (0.06 mol) of pyromellitic dianhydride (PMDA) and 70.6 g (0.24 mol) of 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (s- (PMDA) and biphenyltetracarboxylic acid (s-BPDA) were mixed in a molar ratio of 1: 4, which was used as an aromatic dianhydride, and the mixture was stirred for 3 hours The aromatic diamine and the aromatic dianhydride were subjected to a 1: 1 condensation reaction as a whole to obtain a polyamic acid solution.

After the completion of the reaction, the resulting solution was applied to glass, cast to 80 mu m and dried with hot air at 150 DEG C for 1 hour, and then the film was peeled off from the glass substrate and pinned to the frame.

The frame with the film fixed therein was placed in a vacuum oven and slowly heated from 80 DEG C to 400 DEG C for 8 hours, cooled gradually and separated from the frame to obtain a polyimide film having a thickness of 20 mu m.

Example  2

The same procedure as in Example 1 was followed except that 0.24 mol of p-phenylenediamine was added to dissolve completely. Then, 0.06 mol of pyromellitic acid dianhydride (PMDA) and 3,3 ', 4,4'- And 0.18 mol of biphenyltetracarboxylic dianhydride (s-BPDA) were added, and PMDA and s-BPDA were mixed at a molar ratio of 1: 3 and stirred for 3 hours to obtain an aromatic diamine and an aromatic dianhydride A 1: 1 condensation reaction proceeded as a whole to obtain a polyamic acid solution, and then a polyimide film was prepared.

Example  3

(0.36 mol) of p-phenylenediamine was added and dissolved completely. Then, 0.06 mol of pyromellitic acid dianhydride (PMDA) and 0.06 mol of 3,3 ', 4,4'- 0.32 mol of biphenyltetracarboxylic dianhydride (s-BPDA) was added to the mixture of PMDA and s-BPDA in a molar ratio of 1: 5 and stirred for 3 hours to obtain an aromatic diamine and an aromatic dianhydride A 1: 1 condensation reaction proceeded as a whole to obtain a polyamic acid solution, and then a polyimide film was prepared.

Comparative Example  One

Except that 0.5 mol of p-phenylenediamine was added to complete dissolution. Then, 0.35 mol of pyromellitic acid dianhydride (PMDA) and 0.35 mol of 3,3 ', 4,4'- And 0.15 mol of biphenyltetracarboxylic dianhydride (s-BPDA) was added to mix the PMDA and s-BPDA in a molar ratio of 7: 3, and the mixture was stirred for 3 hours to obtain a polyamic acid solution. A mid-film was produced.

Comparative Example  2

Except that 0.5 mol of p-phenylenediamine was added to complete dissolution. Then, 0.3 mol of pyromellitic acid dianhydride (PMDA) and 0.3 mol of 3,3 ', 4,4'- 0.2 mol of biphenyltetracarboxylic dianhydride (s-BPDA) was added, and PMDA and s-BPDA were mixed at a molar ratio of 3: 2 and stirred for 3 hours to obtain a polyamic acid solution. A mid-film was produced.

Comparative Example  3

The reaction was carried out in the same manner as in Example 1, except that 0.4 mol of p-phenylenediamine was added to dissolve completely, and then 0.2 mol of pyromellitic acid dianhydride (PMDA) and 3 mol% of 3,3 ', 4,4'- 0.2 mol of biphenyltetracarboxylic dianhydride (s-BPDA) was added to mix the PMDA and s-BPDA in a molar ratio of 1: 1, and the mixture was stirred for 3 hours to obtain a polyamic acid solution. A mid-film was produced.

The CTE values of the polyimide films of Examples 1 to 3 and Comparative Examples 1 to 3 were measured at 50 to 300 ° C and 50 to 500 ° C.

division Composition ratio (molar ratio) CTE (ppm / ° C) p-PDA PMDA s-BPDA 50 to 300 ° C 50 to 500 ° C Example 1 5 One 4 -6.3 -4.4 Example 2 4 One 3 -6.1 -4.9 Example 3 6 One 5 -7.0 -3.5 Comparative Example 1 10 7 3 4 7 Comparative Example 2 5 3 2 8 12 Comparative Example 3 2 One One 8 25

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be clear to those who are.

Claims (5)

p-PDA, PMDA and s-BPDA in a molar ratio of 4: 1: 3 to 6: 1: 5,
And a thermal expansion coefficient of -7 to -6.1 ppm / 占 폚 at 50 to 300 占 폚. p-PDA, PMDA and s-BPDA in a molar ratio of 4: 1: 3 to 6: 1: 5,
And a coefficient of thermal expansion of from -4.9 to -3.5 ppm / 占 폚 at 50 to 500 占 폚. 3. The method according to claim 1 or 2,
wherein a condensation reaction takes place at a molar ratio of aromatic diamine of p-PDA to aromatic dianhydride of PMDA and s-BPDA in a 1: 1 molar ratio. 3. The method according to claim 1 or 2,
As a solvent for dissolving p-phenylenediamine (p-PDA), at least one of N-methyl-2-pyrrolidone (NMP), NN'-dimethylformamide and NN'-dimethylacetamide Wherein the polyimide film is a polyimide film. delete