KR20190089688A - Preparation method for polyimide - Google Patents

Abstract

The present invention relates to a method for manufacturing a polyimide. More specifically, the present invention relates to the method for manufacturing the polyimide following steps of: manufacturing a mixture by mixing a dianhydride aqueous solution with a diamine organic solvent solution without pressurized conditions, manufacturing a mixture by mixing the dianhydride aqueous solution with a diamine powder, or manufacturing a mixture by dissolving a dianhydride powder in a mixed solvent of water and an organic solvent and the mixing the diamine powder; and heating the same to obtain the polyimide. When adopting a manufacturing method according to the present invention, it is possible not only to manufacture the polyimide excellent in terms of molecular weight and thermal properties, but also to greatly reduce a cost of synthesis process and lower environmental toxicity.

Description

Preparation method for polyimide < RTI ID = 0.0 >

More particularly, the present invention relates to a process for producing a polyimide, and more particularly, to a process for producing a polyimide, which comprises mixing a solution of a dianhydride aqueous solution and a solution of a diamine organic solvent to prepare a mixture or a mixture of a dianhydride aqueous solution and a diamine powder Or dissolving a dianhydride powder in a mixed solvent of water and an organic solvent, mixing the diamine powder to prepare a mixture, and heating the mixture to obtain a polyimide.

High heat-resistant polymer materials are essential materials for miniaturization, high performance and high reliability of products due to the development of advanced technology. They are used in the form of films, molded products, fibers, paints, adhesives and composites in space, aviation, And precision instruments.

Polyimide (PI) among the high heat-resistant polymer materials has excellent mechanical strength, chemical resistance, weather resistance, and heat resistance based on the chemical stability of the imide ring. In addition, it is easy to synthesize, has the advantage of being able to make thin films, molded products, fibers and does not need a crosslinking agent for curing, and has been attracting attention as a high functional polymer material ranging from microelectronics and optical fields due to its excellent electrical properties .

The polyimide molded article manufacturing method reported so far is to synthesize polyimide and then inject it into a molding apparatus or apply it to the mold. A typical synthesis method of polyimide is a two-step synthesis method in which polyamic acid (PAA), which is a precursor, is synthesized by reacting dianhydride with diamine, and then imidizing polyamic acid in the next step .

In the first step of the method, the dianhydride is added to the reaction solution in which the diamine is dissolved in the production step of the polyamic acid, and the polyamic acid is produced due to the ring-opening, middle-portion reaction. The reaction solvent to be used is N, N-dimethylacetamide, N, N-dimethylformamide, N-methylpyrrolidone, meta-cresol is a polar organic solvent such as a stock price.

In the second step, the polyamic acid prepared in the first step is imidized by a dehydration and ring-closing reaction through a chemical method or a thermal method. The chemical imidization method is a method in which a chemical dehydrating agent such as acetic anhydride such as acetic anhydride and an imidization catalyst typified by tertiary amines such as pyridine are added to a polyamic acid solution as a precursor and heated at 160 ° C or higher. On the other hand, the thermal imidization method is a method in which a precursor polyamic acid solution is applied to a substrate, the solvent is evaporated, and then heated to 250 to 350 ° C without a chemical dehydrating agent and a catalyst.

The fully aliphatic polyimide synthesized using the general polyimide synthesis method described above generally has a low molecular weight and thus has poor mechanical properties. In particular, when an aliphatic diamine is used, the basicity of the amino group of the diamine is high, so that the diamine does not participate in the polymerization reaction but forms a salt with the ammic acid, so that a high molecular weight polyimide can not be obtained.

The second method utilizes the N - silylation reaction. In the first method, diamine and chlorotrimethylsilane are reacted with each other to prevent salt formation and increase the molecular weight to synthesize diamine protected with N - trimethylsilyl group , And polyimide is synthesized using this diamine. In this method, an organic solvent is used for the synthesis of the diamine protected by the N - trimethylsilyl group and for the polyimide synthesis.

N - chamber as a disadvantage of the correlation method is N - trimethylsilyl and the group difficulty in handling very sensitive to the expensive water price of the aliphatic diamine chloro trimethyl silane reagent for synthesizing min protect a number average molecular weight of the polyimide Is about 10,000, and the polyimide synthesis method has a disadvantage that it becomes more complicated than the general synthesis method.

The third method is a method of using meta-cresol as a solvent in which meta-cresol is added as a solvent, dianhydride and diamine are added, and the temperature is increased stepwise to react for a long time.

The meta-cresol method has a long reaction time of more than 64 hours and a molecular weight that can not be satisfied with a number average molecular weight of about 10,000. Since the meta-cresol solvent is used, the drying time is long and the irritating odor is severe Lt; / RTI >

The fourth method is an in-situ method for solving the drawback that the N -seal relation method is sensitive to moisture. After adding diamine to a reactor containing an organic solvent, chlorotrimethylsilane was added at a low temperature and then dianhydride was added to synthesize a polyamic acid protected with N - trimethylsilyl group. After removing the protecting group, the polyimide was passed through polyamic acid, .

A disadvantage of the in situ silylation synthesis method is that the reaction time is long and the molecular weight is improved but the number average molecular weight is about 80,000 and the molecular weight is still unsatisfactory and the chlorotrimethylsilane reagent is expensive, It is necessary to carry out a reprecipitation process in order to synthesize a polyamic acid from which a protecting group has been removed from a polyamic acid protected with a long N - trimethylsilyl group, and it is disadvantageous that sufficient transparency can not be secured even in the case of a battery cyclic polyimide.

With respect to the polyimide synthesis method using an organic solvent, a wholly aromatic polyimide synthesis method is disclosed in High Performance Polymers, 15: 269-279, 2003 and High Performance Polymers, 18: 31-44, 2006. In this method, first, dianhydride is added to water and heated at a reflux temperature to hydrolyze tetracarboxylic acid. When diamine is added to this solution, salt precipitates of tetracarboxylic acid and diamine are formed. Thereafter, the mixture of the precipitate and water is transferred to a glass liner of a pressure device, air is taken out, and nitrogen is filled into the nitrogen atmosphere. Nitrogen is added to the mixture, the pressure is raised to 20 psi, and the mixture is heated at 135 ° C for 1 hour and 180 ° C for 2 hours. The resulting product is filtered and washed with water to obtain a powder, which is washed successively with hot water, methanol, acetone and dichloromethane. The obtained product is placed in a vacuum oven and heated at 40 DEG C overnight to obtain a polyimide powder. However, this method has a disadvantage in that it requires cumbersome synthesis steps and increases manufacturing cost.

In the conventional production of polyimide, most of the synthesis of polyimide using an organic solvent is the most. When an organic solvent is used, there are problems such as economical efficiency, harmfulness, difficulty in post-reaction treatment. Therefore, it is necessary to complement these problems, and at the same time, it is necessary to develop a polyimide powder exhibiting improved properties and a highly marketable production method in terms of economy and harmfulness.

Korean Registered Patent No. 1,004,096 Korea Patent No. 449,798 Korean Registered Patent No. 717,377 U.S. Patent No. 7,053,168 International Patent Application No. 2012-091231 (WO2012 / 91231) International patent application PCT / JP2011 / 066144 (WO 2012/008543) Korean Patent No. 1,714,980

Polymer Science and Technology Vol. 24, No. 1, pp. 3-9, Park Jin-Young et al., Fabrication and Application of Polyimide-Based Particles Macromolecules 2002, 35, 2277-2281 Yasufumi Watanabe, Yoshimasa Sakai, Yuji Shibasaki, Shinji Ando, and Mitsuru Ueda Synthesis of Wholly Alicyclic Polyimides from N-Silylated Alicyclic Diamines and Alicyclic Dianhydrides Yoshiharu Terui, and Kazuhiko Maeda Synthesis of Fluorine-Containing wholly Alicyclic Polyimide by In Situ Silylation Method (In Situ Silylation Method) Journal of photopolymer Science and Technology Volume 16, Number 2 (2003) Youshiyuki Oishi; Shu Ondera; Jan Oravec; Kunio Mori; Shinji Ando; Macromolecules 2009, 42, 5892-5894 Dulce M. Munoz, Mariola Calle, Jose G. de la Campa, Javier de Abajo, and Angel E. Lozano An Improved Method for Preparing Very High Molecular Weight Polyimides Macromolecular Research, Vol. 15, No. 2, pp 114-128 (2007) Anu Stella Mathews, Il Kim, and Chang-Sik Ha Synthesis, Characterization, and Properties of Fully Aliphatic Polyimides and Their Derivatives for Microelectronics and Optoelectronics Applications High Performance Polymers, 15: 269-279, 2003 John Chiefari, Buu Dao, Andrew M. Groth and Jonathan H. Hodgkin Water as Solvent in Polyimide Synthesis: Thermoset and Thermoplastic Examlpes High Performance Polymers, 18: 31-44, 2006 John Chiefari, Buu Dao, Andrew M. Groth and Jonathan H. Hodgkin Water as Solvent in Polyimides Synthesis II: Processable Aromatic Polyimide

In the present invention, it is intended to provide a method for producing polyimide which reduces the amount of an organic solvent by using a mixed solvent of an organic solvent and water in the production of polyimide.

The present invention also provides a process for producing polyimide which does not use an organic solvent by using water as a solvent in the production of polyimide.

The organic solvent used in the present invention is less expensive and less toxic than the organic solvent used in the prior art. The disposal process of the solvent can also be discarded in a relatively simple manner compared to the conventional organic solvent.

In addition, the polyimide prepared by the method of the present invention showed better molecular weight and thermal characteristics than the polyimide synthesized using only the conventional organic solvent.

(A1) mixing an aqueous solution of a dianhydride and a solution of a diamine organic solvent to prepare a mixture; (b) heating the mixture obtained in step (a1); (c) filtering the mixture obtained in step (b) to obtain a solid; And (d) heating the solid obtained in the step (c) to obtain a polyimide.

The present invention also relates to a process for preparing a mixture comprising: (a2) mixing an aqueous solution of a dianhydride and a diamine powder to prepare a mixture; (b) heating the mixture obtained in step (a2); (c) filtering the mixture obtained in step (b) to obtain a solid; And (d) heating the solid obtained in the step (c) to obtain a polyimide.

(A3) dissolving a dianhydride powder in a mixed solvent of water and an organic solvent, and then mixing the diamine powder to prepare a mixture; (b) heating the mixture obtained in step (a3); (c) filtering the mixture obtained in step (b) to obtain a solid; And (d) heating the solid obtained in the step (c) to obtain a polyimide.

The polyimide production method according to the present invention can be carried out by using a mixture of a dianhydride aqueous solution and a diamine organic solvent solution without using a pressurizing condition or using water as a solvent or using a mixed solvent of water and an organic solvent as a solvent The polyimide is produced. As compared with the case where only the existing organic solvent is used, the cost for the synthesis process can be greatly reduced and the environmental toxicity can be lowered. In addition, in view of molecular weight and thermal properties, And has excellent characteristics.

When the production process according to the present invention is adopted, it is possible not only to produce polyimide excellent in molecular weight and thermal properties, but also to greatly reduce the cost of synthesis and to reduce environmental toxicity.

Figure 1 shows a representative structure of a polyimide prepared by the process according to the present invention.
Figure 2 shows the IR analysis results for the polyimide prepared by the process according to the invention.
3A and 3B show the result of thermogravimetric analysis (TGA). FIG. 3A shows a result of thermogravimetric analysis (TGA) of the polyimide prepared through the step a2, (TGA) of the polyimide prepared by the method of the present invention (the polyimide prepared through the step (a2) of the present invention has a higher thermal decomposition rate than the polyimide produced by the conventional method using an organic solvent It can be seen that it represents temperature.)

Hereinafter, the present invention will be described in more detail.

The present invention relates to a process for producing a polyimide in which a polyimide is produced under a pressurized condition using only water or a mixed solvent of water and an organic solvent.

(A1) mixing an aqueous solution of a dianhydride and a solution of a diamine organic solvent to prepare a mixture; (b) heating the mixture obtained in step (a1); (c) filtering the mixture obtained in step (b) to obtain a solid; And (d) heating the solid obtained in step (c) to obtain a polyimide.

The present invention also relates to a process for preparing a mixture comprising: (a2) mixing an aqueous solution of a dianhydride and a diamine powder to prepare a mixture; (b) heating the mixture obtained in step (a2); (c) filtering the mixture obtained in step (b) to obtain a solid; And (d) heating the solid obtained in step (c) to obtain a polyimide.

(A3) dissolving a dianhydride powder in a mixed solvent of water and an organic solvent, and then mixing the diamine powder to prepare a mixture; (b) heating the mixture obtained in step (a3); (c) filtering the mixture obtained in step (b) to obtain a solid; And (d) heating the solid obtained in step (c) to obtain a polyimide.

In one embodiment of the present invention, the polyimide prepared according to the process may be a fully aromatic polyimide, a partially aliphatic polyimide or a fully aliphatic polyimide.

In one aspect of the present invention, the dianhydride is a substituted or unsubstituted aromatic or aliphatic dianhydride compound.

In one aspect of the present invention, the dianhydride may be a dianhydride compound of the formula:

≪ Formula 1 >

In the general formula 1 R ₁ is the chemical structure:

≪ / RTI >

In one embodiment according to the present invention, one or more dianhydrides may be used as the dianhydride compound.

In one aspect of the present invention, the diamines may be substituted or unsubstituted aromatic or aliphatic diamines.

In one aspect of the invention, the diamine may be a diamine of the formula:

H ₂ NR ₂ -NH ₂

(2)

In Formula 2 R ₂ is the chemical structure:

, ≪ / RTI >

X is an integer satisfying 1? X? 50, n is a natural number in the range of 1 to 20,

W, X and Y are each independently a C ₁ to C ₃₀ alkyl group or a C ₃ to C ₃₀ aryl group,

Z is selected from the group consisting of an ester group, an amide group, an imide group and an ether group.

In one embodiment of the present invention, one or more diamines may be used as the diamine compound.

In one embodiment of the present invention, the pressurization condition may not be applied at the time of producing the polyimide.

In one embodiment of the present invention, water may be used in any state of water such as distilled water, deionized water, tap water or the like.

In one embodiment of the present invention, the organic solvent is selected from the group consisting of N -methyl-2-pyrrolidone (NMP), N, N -dimethylformamide (DMF), N, N -dimethylacetamide (DMAc) (DMSO), tetrahydrofuran (THF), pyridine, propanol, acetone, methanol and ethanol, or a mixture of two or more solvents.

In one aspect of the invention,

A step of separately preparing a solution of a dianhydride aqueous solution and a diamine organic solvent in step (a1), or

A step of preparing an aqueous solution of dianhydride in step (a2), or

In the step (a3), the dissolution temperature range in the step of dissolving the dianhydride powder in the mixed solvent of water and the organic solvent is 15 to 90 deg. C, more specifically 30 to 80 deg. C, more specifically 45 to 70 deg. .

If the dissolution temperature is lower than 15 ° C., the dissolution time becomes too long. If the dissolution temperature exceeds 90 ° C., the energy consumption is excessively disadvantageous.

The above-mentioned dissolution temperature means the internal temperature of the container used for dissolution.

In one embodiment of the present invention, the weight ratio of the aqueous solution of the dianhydride and the organic solvent of the diamine in step (al) is from 1: 0.1 to 4, more specifically from 1: 0.2 to 3.5, , More specifically from 1: 0.3 to 2.5, more specifically from 1: 0.35 to 2, even more specifically from 1: 0.4 to 1.5.

In one embodiment of the present invention, the weight ratio of water and organic solvent in step (a3) is from 1: 0.1 to 4, more specifically from 1: 0.2 to 3.5, more specifically from 1: 0.25 to 3, : 0.3 to 2.5, more specifically 1: 0.35 to 2, and even more specifically 1: 0.4 to 1.5.

When the reaction is carried out at the above weight ratio, the amount of the organic solvent used can be reduced, the polyimide synthesis efficiency is high, and the loss can be minimized.

In one embodiment of the invention, the concentration of the monomers (dianhydride and diamine) in the mixture obtained in step (al) is from 3 to 30% by weight, more particularly from 5 to 25% by weight, To 20% by weight.

In one embodiment of the invention, a mixture of an aqueous solution of dianhydride and a diamine powder may be prepared in step (a2). The concentration of the monomers (dianhydride and diamine) in the resulting mixture may be from 3 to 30% by weight, more specifically from 5 to 25% by weight, and even more specifically from 7 to 20% by weight.

In one embodiment of the present invention, in step (a3), the mixture may be prepared by dissolving the dianhydride powder in a mixed solvent of water and an organic solvent, and then mixing the diamine powder. The concentration of the monomers (dianhydride and diamine) in the resulting mixture may be from 3 to 30% by weight, more specifically from 5 to 25% by weight, and even more specifically from 7 to 20% by weight.

If the concentration of the monomer is less than 3% by weight, an excess amount of solvent is economically disadvantageous. If the monomer concentration is more than 30% by weight, the insoluble solid is too much to proceed efficiently.

In one embodiment of the invention, the reaction temperature in step (b) may be between 15 and 110 < 0 > C. When heated to the above temperature range, the dianhydride and diamine can react efficiently. The reaction does not proceed well at temperatures below 15 ° C, and heating above 110 ° C may cause hydrolysis of the polymer.

The above-mentioned reaction temperature means the internal temperature of the reaction vessel used for the reaction.

In one embodiment of the present invention, in the step (b), heating is carried out for 6 to 36 hours, more specifically for 8 to 32 hours, more particularly for 10 to 28 hours, more particularly for 12 Lt; / RTI > to 24 hours.

When the reaction time is within the above range, the reaction is sufficiently carried out, and a solid powder can be sufficiently obtained. When the reaction time is less than 6 hours, the reaction is not sufficiently performed, and when the reaction time exceeds 36 hours, the polymer may be hydrolyzed.

In one embodiment of the present invention, the heating temperature in step (d) ranges from 50 to 400 캜. More specifically from 60 to 350 占 폚, more specifically from 80 to 320 占 폚, and still more specifically from 100 to 300 占 폚.

When heated to the above-mentioned temperature range and time range, thermal imidization proceeds well and a polyimide having a high imidization ratio can be produced. If heated to less than 50 ° C, imidization does not occur sufficiently, and if heated above 400 ° C, thermal decomposition of the polymer may proceed.

The above-mentioned heating temperature means the internal temperature of the oven or furnace used in the imidization reaction.

In one embodiment of the present invention, the step (d) can be divided into two or more steps at the time of heating, and the heating can be performed by a heating method. In this case, the temperature can be raised in the range of 50 to 150 ° C, or in the interval of 80 to 120 ° C, or in the interval of about 100 ° C.

In addition, it can be divided into two or more stages and heated at each step for 30 minutes to 180 minutes, more specifically for 40 minutes to 160 minutes, more specifically for 50 minutes to 140 minutes, more specifically for about 60 minutes to 120 minutes, .

As described above, it is possible to remove residual solvent at a relatively low temperature by heating and heating at two or more stages during heating, and it is expected that the effect of selectively advancing high thermal imidization at a relatively high temperature can be expected .

In another embodiment of the present invention, there is provided a polyimide produced according to the above production method.

The polyimide synthesized by the production method of the present invention can be used in a wide range of industries including space, aviation, electric / electronic, semiconductor, transparent / flexible display, liquid crystal alignment film, automobile, precision instrument, packaging, medical material, separator, fuel cell, Can be used in the field.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. It should be understood, however, that the following Examples and Experiments are intended to assist the understanding of the present invention and are not intended to limit the scope of the present invention thereto.

Example  One: Reaction solvent  Preparation of polyimide powder using water as a part

Distilled water was added to a 100-mL 2-necked round-bottomed flask substituted with nitrogen gas, and 1.09 g (0.005 mol) of pyromellitic dianhydride was added thereto, followed by refluxing and dissolving at a dissolution temperature of 80 ° C. Another 100-mL 1-neck round bottom flask was charged with 1.00 g (0.005 mol) of 4,4'-oxydianiline and dissolved at a dissolution temperature of 60 ° C. 4,4'-oxydianiline was dissolved in pyromellitic dianhydride in a round bottom flask containing an aqueous solution, and the two solutions were mixed and heated at a reaction temperature of 80 ° C for 24 hours to produce a powder. The weight ratio of the aqueous solution to the THF solution was 7: 3.

The powder thus produced was heated in an oven at 100 ° C, 200 ° C and 300 ° C for 90 minutes, respectively, to conduct thermal imidization, thereby preparing a polyimide powder.

The viscosity of the prepared polyimide powder was measured, and the thermal stability was measured using a thermogravimetric analyzer.

Example  2: Reaction solvent  Preparation of polyimide powder using water as a part

Distilled water was added to a 100-mL 2-necked round-bottomed flask substituted with nitrogen gas, and 1.09 g (0.005 mol) of pyromellitic dianhydride was added thereto, followed by refluxing and dissolving at a dissolution temperature of 80 ° C. Another 100-mL 1-necked round bottom flask was charged with acetone, 1.00 g (0.005 mol) of 4,4'-oxydianiline, and dissolved at a dissolution temperature of 60 ° C. 4,4'-oxydianiline was dissolved in pyromellitic dianhydride in a round bottom flask containing an aqueous solution, and the two solutions were mixed and heated at a reaction temperature of 80 ° C for 24 hours to produce a powder. The weight ratio of aqueous solution to acetone solution was 5: 5.

The powder thus produced was heated in an oven at 100 ° C, 200 ° C and 300 ° C for 90 minutes, respectively, to conduct thermal imidization, thereby preparing a polyimide powder.

The viscosity of the prepared polyimide powder was measured, and the thermal stability was measured using a thermogravimetric analyzer.

Example  3: As a reaction solvent  Preparation of polyimide powder using water

Distilled water was added to a 100-mL 2-necked round-bottom flask substituted with nitrogen gas, and 1.09 g (0.005 mol) of pyromellitic dianhydride was added thereto, followed by refluxing and dissolving at a dissolution temperature of 80 ° C. 1.00 g (0.005 mol) of 4,4'-oxydianiline was mixed in a round bottom flask containing an aqueous solution of pyromellitic dianhydride dissolved therein and heated at a reaction temperature of 80 ° C for 24 hours to produce a powder.

The powder thus produced was heated in an oven at 100 ° C, 200 ° C and 300 ° C for 90 minutes, respectively, to conduct thermal imidization, thereby preparing a polyimide powder.

The viscosity of the prepared polyimide powder was measured, and the thermal stability was measured using a thermogravimetric analyzer.

Example 4: Preparation of polyimide powder using water as a part of reaction solvent at room temperature

To a 100-mL 2-neck round bottom flask substituted with nitrogen gas, distilled water and acetone were added at a weight ratio of 1: 1, and 1.09 g (0.005 mol) of pyromellitic dianhydride was added thereto and dissolved at a dissolving temperature of 15 ° C. (0.005 mol) of 4,4'-oxydianiline were mixed in a round bottom flask containing a solution of pyromellitic dianhydride dissolved therein and reacted at a reaction temperature of 15 ° C for 24 hours to produce a powder.

The powder thus produced was heated in an oven at 100 ° C, 200 ° C and 300 ° C for 90 minutes, respectively, to conduct thermal imidization, thereby preparing a polyimide powder.

The viscosity of the prepared polyimide powder was measured, and the thermal stability was measured using a thermogravimetric analyzer.

Comparative Example 1: Production of polyimide using organic solvent

N -methyl-2-pyrrolidone (NMP) was added to a 100-mL two-neck round bottom flask substituted with nitrogen gas, and 1.00 g (0.005 mol) of 4,4'-oxydianiline was added thereto. Lt; / RTI > (0.005 mol) of pyromellitic dianhydride were mixed in a round bottom flask containing a solution of 4,4'-oxydianiline dissolved therein and reacted at a reaction temperature of 15 ° C for 24 hours to synthesize a polyamic acid solution.

Next, the polyamic acid solution was reprecipitated in distilled water, and the resulting solid was heated in an oven at 100 ° C, 200 ° C, and 300 ° C for 90 minutes, respectively, for thermal imidization, thereby producing polyimide.

The viscosity of the prepared polyimide powder was measured, and the thermal stability was measured using a thermogravimetric analyzer. The results are shown in Table 1 below.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 menstruum Water / THF Water / acetone water Water / acetone NMP Intrinsic viscosity (dL / g) * 1.2 1.3 1.1 1.4 0.9 Pyrolysis temperature (10% weight reduction temperature) 578 ° C 585 DEG C 582 DEG C 588 ° C 569 ° C

* Dissolved in concentrated sulfuric acid at a concentration of 0.5 g / dL and measured at 30 ° C.

The polyimide synthesizing method of the present invention is simpler and more environmentally friendly than the conventional method, and the polyimide synthesized by the method of the present invention has a higher molecular weight than the polyimide produced by the conventional synthetic method, has excellent mechanical properties, .

Claims (18)

(a1) mixing a solution of a dianhydride aqueous solution and a diamine organic solvent solution to prepare a mixture,
(a2) mixing the aqueous solution of the dianhydride and the diamine powder to prepare a mixture, or
(a3) dissolving a dianhydride powder in a mixed solvent of water and an organic solvent, and then mixing the diamine powder to prepare a mixture;
(b) heating the mixture obtained in step (a1), step (a2) or step (a3);
(c) filtering the mixture obtained in step (b) to obtain a solid; And
(d) heating the solid obtained in step (c) to obtain a polyimide.
The method according to claim 1,
Wherein the dianhydride is an aromatic or aliphatic dianhydride.
The method according to claim 1,
Wherein said dianhydride is a dianhydride of formula (1): < EMI ID =

&Lt; Formula 1 &gt;
In the general formula 1 R ₁ is the chemical structure:

&Lt; / RTI &gt;
The method according to claim 1,
Wherein the diamine is an aromatic or aliphatic diamine.
The method according to claim 1,
Wherein the diamine is a diamine of the following formula 2:
H ₂ NR ₂ -NH ₂
(2)
In Formula 2 R ₂ is the chemical structure:

, &Lt; / RTI >
X is an integer satisfying 1 &lt; = x &lt; = 50,
Wherein n is a natural number ranging from 1 to 20,
W, X and Y are each independently a C ₁ to C ₃₀ alkyl group or a C ₃ to C ₃₀ aryl group,
Z is selected from the group consisting of an ester group, an amide group, an imide group and an ether group.
The method according to claim 1,
Wherein no pressure condition is applied.
The method according to claim 1,
A step of separately preparing a solution of a dianhydride aqueous solution and a diamine organic solvent in step (a1), or
A step of preparing an aqueous solution of dianhydride in step (a2), or
Wherein the dissolution temperature range in the step of dissolving the dianhydride powder in a mixed solvent of water and an organic solvent in step (a3) is 15 to 90 占 폚.
8. The method of claim 7,
Wherein the melting temperature range is 30 to 80 占 폚.
The method according to claim 1,
The organic solvent may be selected from the group consisting of N -methyl-2-pyrrolidone (NMP), N, N -dimethylformamide (DMF), N, N -dimethylacetamide (DMAc), dimethylsulfoxide (THF), a single solvent selected from the group consisting of pyridine, propanol, acetone, methanol and ethanol, or a mixture of two or more solvents.
The method according to claim 1,
Wherein the weight ratio of the dianhydride aqueous solution and the organic solvent solution of diamine in step (a1) is 1: 0.1 to 4.
The method according to claim 1,
Wherein the weight ratio of water and the organic solvent in step (a3) is 1: 0.1 to 4.
The method according to claim 1,
A mixed solution of the aqueous solution of the dianhydride and the diamine organic solution of step (a1) or
A mixture of the aqueous solution of the dianhydride of step (a2) and the diamine powder or
In a mixture of water and an organic solvent, a dianhydride, and a diamine in the step (a3)
Wherein the concentration of the dianhydride and the diamine is 3 to 30% by weight.
The method according to claim 1,
And the reaction temperature in step (b) is 15 占 폚 to 110 占 폚.
The method according to claim 1,
And heating in the step (b) for 6 to 36 hours during heating.
The method according to claim 1,
Wherein the heating temperature in step (d) is 50 to 400 占 폚.
The method according to claim 1,
In the step (d), the heating is divided into two or more steps,
And raising the temperature at an interval in the range of 50 to 150 占 폚.
17. The method of claim 16,
Wherein the polyimide is heated in each step at a temperature rising time of 30 minutes to 180 minutes.
17. A polyimide prepared according to the process of any one of claims 1 to 17.

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