KR20160077479A - Manufacturing method of polyimide precursor solution, polyimide film manufactured using the same - Google Patents

Abstract

The present invention relates to a method for producing a polyimide precursor, by producing a dianhydride solution and a diamine solution respectively at a certain concentration when adding dianhydride and diamine and then loading the solutions in a droplet form into a polymerizing solvent. According to the present invention, difference in configurational properties decreases in comparison with a case for injecting solid monomers, thereby securing uniform material properties. In addition, a polyimide film using the polyimide precursor solution produced thereby exhibits excellent mechanical properties and secures operational stability during a post-process.

Description

[0001] The present invention relates to a method for producing a polyimide precursor solution and a polyimide film prepared using the same,

The present invention relates to a process for preparing a polyimide precursor solution and a polyimide film produced using the same, and more particularly, to a process for producing a polyimide precursor solution by adding dropwise dianhydride and diamine monomers to a polymerization solvent, To a method for producing a polyimide precursor solution which can reduce variations in physical properties between batches and increase the quality uniformity of a product and a polyimide film produced using the same.

Polyimide refers to a high heat-resistant resin prepared by solution polymerization of an aromatic dianhydride with an aromatic diamine or aromatic diisocyanate to prepare a polyamic acid derivative, followed by ring-closing dehydration at a high temperature and imidization. Polyimide has excellent properties in heat resistance, chemical resistance, mechanical properties, electrical properties and dimensional stability, and is used in a wide range of electric / electronic materials such as aerospace, circuit board, and liquid crystal alignment film.

The polyimide precursor is generally prepared in batch form due to the nature of the feedstock and reaction conditions. Generally, polyimide precursors are prepared by charging dianhydride and diamine in the same molar ratio in a polar solvent. In order to prepare such a polyimide, pyromellitic acid dianhydride (PMDA) or biphenyltetracarboxylic acid dianhydride (BPDA) or the like is used as an aromatic dianhydride component, and as an aromatic diamine component, oxydianiline (ODA ), p-phenylenediamine (p-PDA), m-phenylenediamine (m-PDA), methylenedianiline (MDA), and bisaminophenylhexafluoropropane (HFDA).

The molecular weight of the polyimide precursor is determined by the molar ratio of the monomers charged into the batch, which directly affects the physical properties of the film produced through post-processing. Therefore, in order to inject the monomer at an appropriate molar ratio, the amount of the monomer to be added must be able to participate in the reaction.

When a polyimide precursor is prepared in a batch manner, when a dianhydride and a diamine are added in a solid state, even if the same conditions are applied, there is a difference in physical properties between batches, which makes it difficult to obtain uniform physical properties. In the method of injecting the monomer into the solid state, it is common to gradually inject the monomer in the form of powder into the polymerization solvent. In this process, when the monomer in powder form sticks to the reactor wall or disappears during the charging process, . Due to this, an appropriate molar ratio between the monomers is not formed, resulting in a difference in molar ratio between the batches, resulting in uneven physical properties of the polyimide precursor. In addition, when a polyimide precursor prepared by introducing a solid state monomer into a polyimide film is used, workability is deteriorated due to a non-uniform precursor, and mechanical properties are deteriorated.

Therefore, there is an increasing need for research for producing a polyimide precursor having improved uniformity of polyimide precursor, improving the quality of the product, and excellent post-processability.

It is an object of the present invention to provide a method for producing a polyimide precursor having excellent dimensional stability and uniform physical properties of a polymerized material by reducing the difference in physical properties between batches.

Another object of the present invention is to provide a polyimide film having improved mechanical properties, excellent quality uniformity of the product, and excellent after-processability.

According to an aspect of the present invention,

Dissolving a diamine compound in a polymerization solvent to prepare a 30 to 40 wt% diamine solution;

Dropping the diamine solution into a reaction vessel containing a polymerization solvent in a droplet state;

Dissolving a dianhydride compound in a polymerization solvent to prepare a 30 to 40 wt% dianhydride solution; And

The diamine solution and the dianhydride solution are added dropwise to the diamine solution in the reaction vessel while dropwise adding the diamine solution dropwise to the diamine solution, and the concentration of the diamine solution and the dianhydride solution is adjusted to 10 to 20 wt% in the mixed solution of the diamine solution and the dianhydride solution And a method for producing a polyimide precursor solution.

According to another aspect of the present invention, there is provided a polyimide film using the polyimide precursor prepared by the process for producing the polyimide precursor solution.

According to the method for producing a polyimide precursor solution according to the present invention, the dissolution state of two diamines and dianhydride monomers used as raw materials are made uniform, so that the difference in physical properties between batches is reduced Uniform physical properties can be secured. The polyimide film using the polyimide precursor solution prepared in this way has excellent mechanical properties and secures stability in the post-processing.

Hereinafter, a method for producing a polyimide according to the present invention will be described in detail with reference to examples.

The present invention relates to a process for preparing a polyimide precursor which is prepared by adding dianhydride solution and diamine solution at the same molar ratio, wherein each of the dianhydride solution and the diamine solution The present invention relates to a method for producing a polyimide precursor by first preparing the polyimide precursor and then dropwise in droplet form into a polymerization solvent.

First, a 30 to 40 wt% diamine solution in which a diamine compound is dissolved in a polymerization solvent is prepared in a storage tank, and the prepared diamine solution is added dropwise to a polymerization solvent contained in the reaction vessel.

On the other hand, a dianhydride solution in which a dianhydride compound is dissolved in a polymerization solvent is prepared in a storage tank. The concentration of the dianhydride solution is preferably 30 to 40 wt%.

The prepared dianhydride solution is added dropwise to the reaction vessel containing the diamine solution in a droplet state to prepare a polyimide precursor solution. At this time, the concentrations of the diamine solution and the dianhydride solution mixed in the reaction tank are adjusted to 10 to 20 wt%, respectively.

Specific examples of the dianhydride compound include 4-4- (2,2,2-trifluoro-1-phenylethylidene) diphthalic anhydride (3FDAh), pyromellitic dianhydride (PMDA) , 3,3 ', 4,4'-biphenyltetracarboxylic dianhydride (BPDA), 3,3', 4,4'-benzophenone tetracarboxylic dianhydride (TDA), 4,4'- (ODPA), 2,2'-bis- (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA), cyclobutane-1,2,3,4-tetra (CBDA), cyclohexanediamine hydrate (CHDA), and the like, but are not limited thereto.

Specific examples of the diamine compound include 1,1-bis (4-aminophenyl) -1-phenyl-2,2,3-trifluoroethane, bistrifluoromethylbenzidine (TFDB), p- (p-PDA), m-phenylenediamine (m-PDA), bis (3-aminophenyl) sulfone (3-DDS), bis (4,4'-ODA), 3,3'-oxydianiline (3,3'-ODA), 2,2-bis ), Bisaminophenoxyphenylhexafluoropropane (DBOH), cyclohexanediamine (1,4-CHDA) and 2,2-bis (4- [3-aminophenoxy] phenyl) sulfone , But is not limited thereto.

The diamine compound and the dianhydride compound are dissolved in a polymerization solvent. The polymerization solvent may be any of those known in the art without limitation, but 1,3-dimethyl-2-imidazolidinone (DMI), N-methylpiperazine N-dimethylacetamide (DMAc), tetrahydrofuran (THF), N, Ndimethylformamide (DMF), dimethyl (N, N-dimethylacetamide) Dimethylsulfoxide (DMSO), cyclohexane, and acetonitrile, or a mixture thereof may be used.

According to the present invention, it is preferable that the concentrations of the dianhydride solution and the diamine solution in the polyimide precursor solution are 10 to 20 wt%, respectively. When the concentration of the dianhydride solution and / or the diamine solution is less than 10 wt%, the molecular weight of the polyimide precursor to be prepared is lowered. When the concentration of the dianhydride solution and / or the diamine solution is more than 20 wt%, the viscosity of the precursor becomes too high, .

When such a monomer in a solution state is added, a molecular weight somewhat lower than that in a solid state is formed. However, when a solvent of high purity in which water is sufficiently removed through purification of a solvent is used, a polyimide precursor It is possible to manufacture. Therefore, the solvent used in the present invention should be purified to a high purity. The purity of the solvent should exceed 99.99% and the moisture content should not exceed 100 ppm. Preferably, the water content is 10 to 50 ppm. When the water content of the solvent is more than 100 ppm, the dianhydride and / or diamine may be degraded by moisture, and decomposition may occur by moisture during the formation of the polyimide precursor.

The reaction of the diamine solution and the dianhydride solution may be carried out at 0 to 20 ° C for 1 to 5 hours, preferably at room temperature for about 4 hours. When the reaction is carried out for a longer time, the molecular weight of the polyimide precursor to be produced is lowered and the reaction efficiency is not increased, so that the reaction time is lengthened and the production efficiency may be lowered.

The diamine solution and the dianhydride solution may be reacted at a molar ratio of 1: 1 to 1: 1.02, preferably at a molar ratio of 1: 1.01. If the molar ratio of the diamine solution to the dianhydride solution is less than 1: 1, the molecular weight may be small and the heat resistance may be deteriorated. If the molar ratio exceeds 1: 1.02, a polymer having a desired molecular weight can not be obtained, And the viscosity may be lowered, which may make the coating and processing process difficult.

The diamine solution and the dianhydride solution may be used alone or in combination of two or more kinds of monomers.

The imidization step is a step of adding a catalyst to the precursor solution or heating to produce the polyimide as the final product. The imidization can be carried out by introducing the imidation catalyst into the precursor solution to advance the chemical imidization. The imidization catalyst may be any of those known in the art without limitation, and specifically includes acid anhydrides such as acetic anhydride, isoquinoline,? -Picoline, pyridine, azole, phosphine, malononitrile, Dimethylpiperidine, triethylamine, N, N, N, N'-tetramethylethylenediamine, triphenylphosphine, 4-dimethylaminopyridine, tripropylamine, tributylamine, N, 1,2,4-triazole, triisobutylamine, and the like.

The imidization can be carried out in combination with chemical imidization and thermal imidization. Specifically, a dehydrating agent and an imidization catalyst may be added to the precursor solution and heated to activate the dehydrating agent and the imidization catalyst, thereby partially imidizing the precursor solution. The imidization can proceed at 50 to 400 ° C and can be imidized at 90% or more by heating at 200 to 400 ° C for 30 minutes or more.

The imidization catalyst may be added to the precursor solution at a molar ratio of 1: 1 or more, preferably 1: 3 or more. If the imidization catalyst is added in an excess molar amount relative to the precursor solution, the dehydration reaction can be effectively induced, and the imidization can proceed smoothly and the imidization can proceed at a lower temperature, so that the thermal stability degradation due to the long- Can be prevented.

The present invention also provides a polyimide film using the polyimide precursor solution prepared by the method for producing the polyimide precursor solution.

The polyimide film may be produced by a conventional method known in the art. The polyimide film may be prepared from the precursor solution formed in the production of the polyimide of the present invention. Specifically, the precursor solution may be cast on a support and imidized to prepare a film. In addition, additives or fillers known in the art can be added during the casting. The imidization may be thermal imidization, chemical imidization, or thermal imidization and chemical imidization. Specifically, a polyimide film can be prepared by introducing a dehydrating agent and an imidation catalyst into a precursor solution, casting it, and then heating the mixture at a temperature ranging from room temperature to 150 ° C for 1 to 12 hours to imidize the polyimide film. At this time, the precursor solution may partially be imidized and contain a solid content, and the solid content is preferably 5 to 30% by weight based on the total precursor solution. In addition, the precursor solution may be thermally imidized by heating it for 1 minute to 4 hours while slowly heating the solution at a temperature of 40 to 400 ° C after casting on the support.

The polyimide film may be prepared by placing the precursor solution in a solvent such as water, methanol, or ethyl ether having a lower polarity than the polymerization solvent and precipitating to obtain a solid component, dissolving the precursor solution in a solvent, casting it on a support, and imidizing it. The solvent may be any solvent known in the art without limitation, and specific examples thereof include 1,3-dimethyl-2-imidazolidinone, N-methylpyrrolidinone, N, N-dimethylacetamide, Furan, N, N-dimethylformamide, dimethylsulfoxide, cyclohexane, and acetonitrile, or a mixture thereof.

The polyimide film manufacturing method may further include a heat treatment step of performing heat treatment for 1 to 30 minutes at a temperature of 150 to 450 DEG C under a predetermined tension. In the case of thermal imidization, the thermal history that occurs during the film forming process may lower the thermal stability of the final imide product, so that the thermal history can be removed through the heat treatment process.

Hereinafter, the present invention will be described in detail with reference to specific examples. The embodiments shown are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

≪ Example 1: Preparation of polyimide precursor solution and polyimide film >

100 g of dimethylacetamide was charged into a 500-mL round flask equipped with a stirrer, a nitrogen inlet, a dropping funnel, a temperature controller and a condenser, and oxydianiline was dissolved at 33.78 wt% Lt; / RTI > dropwise in acetamide solvent.

Then, pyromellitic dianhydride (PMDA) was dissolved in dimethylacetamide in a concentration of 36.80 wt% to prepare a solution. The solution was gradually dropped into the oxydianiline solution in the form of droplets at room temperature and stirred for 4 hours To prepare a polyimide precursor solution.

These procedures were repeated 5 times to determine the properties of the polyimide precursor solutions prepared in Examples 1 to 5, respectively, and the properties of the polyimide precursor solution during the placement were shown in Table 1 below.

The polyimide precursor solution prepared in Examples 1 to 5 was coated on a stainless steel plate, cast to about 400 탆 and dried at a temperature of 90 캜 for 1 hour. The film was peeled off from the stainless plate and fixed to the frame. The frame with the film fixed therein was placed in an oven and slowly heated from 100 ° C to 300 ° C for 2 hours, cooled gradually and separated from the frame to obtain a polyimide film. Further, in order to prevent thermal stability from being degraded due to thermal history during the film-forming process, the polyimide film was heat-treated at 350 ° C for 30 minutes to obtain a polyimide film having a final thickness of 50 μm.

The tensile strength, elongation and thermal expansion coefficient of the polyimide film thus prepared were measured and reported in Table 1 below.

≪ Comparative Examples 1 to 5: Preparation of polyimide precursor solution and polyimide film >

In a 500 mL round flask equipped with a stirrer, a nitrogen introducing device, a dropping funnel, a temperature controller and a condenser, 200 g of dimethylacetamide was charged while passing nitrogen, and 16.89 g of oxydianiline was dissolved in the solid state at room temperature. Then, 18.40 g of pyromellitic dianhydride was stirred while being slowly added to a solid state. These procedures were repeated five times to determine the respective Comparative Examples 1 to 5, and the physical properties of the polyimide precursor solution prepared in Comparative Examples 1 to 5 between the batches are shown in Table 1 below.

The polyimide precursor solution prepared in Comparative Examples 1 to 5 was applied to a stainless steel plate, cast to about 400 탆 and dried at a temperature of 90 캜 for 1 hour. The film was peeled off from the stainless plate and fixed to the frame. The frame with the film fixed therein was placed in an oven and slowly heated from 100 ° C to 300 ° C for 2 hours, cooled gradually and separated from the frame to obtain a polyimide film. Further, in order to prevent thermal stability from being degraded due to thermal history during the film-forming process, the polyimide film was heat-treated at 350 ° C for 30 minutes to obtain a polyimide film having a final thickness of 50 μm.

The tensile strength, elongation and thermal expansion coefficient of the polyimide film thus prepared were measured and reported in Table 1 below.

≪ Measurement of physical properties of polyimide film &

1. Measurement of tensile strength and elongation

Using a TENSILON UTM-2 (manufactured by A & D Company), the polyimide film was cut into 3 mm x 35 mm, fixed on the jig, and set in a tensile tester so that the distance between the chucks was 20 mm. And a tensile test was carried out at a crosshead speed of 8 mm / min to measure a tensile strength and an elongation.

2. Measurement of the coefficient of thermal expansion (CTE)

(First run), second run (third run), and third run (according to the TMA method) using TMA (Perkin Elmer, Diamond TMA) The thermal expansion coefficient at 50 to 200 占 폚 was measured. That is, the temperature was increased from 30 ° C to 230 ° C, then decreased again to 30 ° C, and then increased to 230 ° C again. This was repeated three times, and the results are shown in Table 1 below.

division Input method Polyimide precursor Polyimide film Viscosity IV The tensile strength
(Mpa) Elongation
(%) CTE
(ppm / DEG C) Example 1 solution 2,486 1.785 243 88 26 Example 2 solution 2,492 1.788 244 87 26 Example 3 solution 2,490 1.786 244 87 26 Example 4 solution 2,477 1.783 242 88 27 Example 5 solution 2,493 1.788 244 87 26 Property difference ㅡ 26 0.005 2 One One Comparative Example 1 solid 2,512 1.796 251 83 24 Comparative Example 2 solid 2,476 1.782 241 89 27 Comparative Example 3 solid 2,531 1.801 252 84 23 Comparative Example 4 solid 2,502 1.790 250 80 24 Comparative Example 5 solid 2,465 1.778 238 90 28 Property difference ㅡ 66 0.023 13 10 5

Examples 1 to 5 are the results of analysis of a polyimide precursor solution prepared by dropwise adding dianhydride and diamine monomers according to the present invention to a polymerization solvent in a solution state and a polyimide film prepared using the same, 5 shows the results of analysis of the polyimide precursor solution prepared by introducing the conventional powder type monomer and the polyimide film prepared using the same. Referring to Table 1, it can be seen that, when the dianhydride and the diamine are added in a solid state, there is a large difference in property between batches even under the same conditions. In Examples 1 to 5, the difference in physical properties between the batches was relatively reduced by introducing the dianhydride and the diamine in the solution state, and the mechanical properties of the produced film were excellent.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, The facts will be apparent to those skilled in the art. Accordingly, the scope of protection of the present invention should be defined in the appended claims and their equivalents.

Claims (8)

Dissolving a diamine compound in a polymerization solvent to prepare a 30 to 40 wt% diamine solution;
Dropping the diamine solution in a droplet state into a reaction vessel containing a polymerization solvent;
Dissolving a dianhydride compound in a polymerization solvent to prepare a 30 to 40 wt% dianhydride solution; And
The diamine solution and the dianhydride solution are added dropwise to the diamine solution in the reaction vessel while dropwise adding the diamine solution dropwise to the diamine solution, and the concentration of the diamine solution and the dianhydride solution is adjusted to 10 to 20 wt% in the mixed solution of the diamine solution and the dianhydride solution ≪ / RTI > wherein the polyimide precursor solution is a polyimide precursor solution.
The process for preparing a polyimide precursor solution according to claim 1, wherein the polymerization solvent has a water content of 10 to 50 ppm.
The method according to claim 1, wherein the reaction of the diamine solution and the dianhydride solution is performed at 0 to 20 ° C for 1 to 5 hours.
The method of claim 1, wherein the diamine solution and the dianhydride solution are reacted at a molar ratio of 1: 1 to 1: 1.02.
The method according to claim 1, wherein the polymerization solvent is selected from the group consisting of 1,3-dimethylimidazolidinone, N-methylpyrrolidinone, N, N-dimethylacetamide, tetrahydrofuran, N, N-dimethylformamide, dimethylsulfoxide , Cyclohexane, and acetonitrile, or a mixture thereof. The method of producing a polyimide precursor solution according to claim 1,
A method for producing a polyimide comprising the steps of: (a) heating a solution of the polyimide precursor prepared according to claim 1 to form an end product;
A polyimide produced by the method according to claim 6.
A polyimide film produced by using the polyimide according to claim 7.