KR101648745B1 - Low temperature curable polyimides with high packing structure and organic thin film transistor devices using them - Google Patents

Abstract

The present invention relates to a polyimide insulating film prepared from a low-temperature-curing polyamic acid resin composition and an all-organic thin film transistor using the same. More particularly, the present invention relates to a polyimide insulating film prepared by polymerization reaction of an aromatic tetracarboxylic acid dianhydride having a high packing structure with an aromatic diamine monomer A low-boiling organic catalyst capable of low-temperature curing can be contained as an essential component in the imidization reaction of a polyamic acid resin, so that a low temperature imidation reaction in a temperature range of 100 to 200 ° C is possible. lt; RTI ID = 0.0 > ppm / ppm, < / RTI >

Low temperature curing, polyamic acid, polyimide, imidization degree, organic insulator, organic thin film transistor

Description

TECHNICAL FIELD The present invention relates to a low temperature curable polyimide insulator made from a polyamic acid resin composition having a high packing structure and an organic thin film transistor device having low hysteresis characteristics using the low temperature curable polyimide insulator.

The present invention relates to a high-packing-structure polyimide insulating film prepared by imidizing a polyamic acid under an aminoalcohol catalyst useful as a catalyst for imidization reaction, and an all-organic thin film transistor device using the same. More particularly, the present invention relates to an aromatic tetracarboxylic acid diimide An imidization reaction at 100 to 200 ° C is possible by incorporating an organic catalyst capable of curing at low temperatures in an imidization reaction of a polyamic acid resin prepared by polymerizing water and an aromatic diamine monomer, Temperature curing type polyamic acid resin composition to which a high packing structure is imparted, and an all organic thin film transistor element fabricated therefrom.

The imidization reaction proceeding under the low-temperature curing type catalyst according to the present invention can be carried out smoothly even at a high imidization reaction temperature of 200 ° C or higher and at a low temperature of 100 to 200 ° C and the amount of catalyst remaining in the produced polyimide is remarkably improved Thereby obtaining an effect of providing a whole organic thin film transistor element having excellent stability over time.

The polyimide resin is a high heat-resistant resin prepared by condensation polymerization of an aromatic tetracarboxylic acid or a derivative thereof with an aromatic diamine or an aromatic diisocyanate, and may have various molecular structures depending on the type of the monomer used.

Such polyimide resin is an insoluble and highly heat resistant resin having the following characteristics: (1) Excellent heat resistance and oxidation resistance, (2) Highly usable temperature, long service temperature is about 260 ℃, (3) Excellent electrochemical and mechanical properties, (4) Excellent radiation resistance and low temperature characteristics, (5) High flammability, (6) Excellent chemical resistance.

 Generally, polyimide is synthesized by using polyamic acid, which is obtained by condensing an aromatic tetracarboxylic acid dianhydride and an aromatic diamine in a solvent as an amide group linkage, as a precursor by heating and dehydrating it to form an imide ring, Dehydration by a dehydration method, and cyclization.

The polyimide generally has a glass transition temperature of 350 DEG C or more and is very high in inherent characteristics. Once the polyimide is formed from polyamic acid by imidization, it is difficult to form the polyimide by heating to a temperature higher than the glass transition temperature. , The resin is obtained from the polyamic acid by the necessity of a film or the like when the polyimide is formed.

A method of forming a polyimide from a polyamic acid by dehydration cyclization by a heating method generally requires a high temperature of 300 ° C to 400 ° C and it is difficult to form the polyimide after the polyimide is formed so that a polyimide thin film or a film is formed Imidization is performed on the part material that is desired. When the general film type polyimide is produced, the limitation of the production temperature is limited to the energy consumption and the design of the production apparatus. However, if the polyimide formation site is not suitable for the high temperature process, the formation of the polyimide itself becomes difficult. Particularly, in the field of organic material electronic component parts, which is actively under progress in recent years, it is required to lower the formation temperature of polyimide to 200 占 폚 or less in the fields where it is applied as an interlayer insulating material and a covering material.

The method of forming a polyimide by dehydration cyclization by a chemical method using a dehydrating agent enables formation of polyimide even at a temperature as low as 200 DEG C or lower, but by using a dehydrating agent equal to or more than the equivalent amount, dehydration by- The polyimide formed by imidization which is not formed has a disadvantage that its physical properties are poor.

Also, a method of forming a polyimide by imidization under the condition of using a catalyst such as acid or base together with a dehydrating agent has been known. At this time, as an acid catalyst, it has been reported that polyimide is obtained by proceeding imidization at a low temperature of 200 ° C or lower using an organic acid such as p -hydroxyphenylacetic acid [M. Oba, J. Polym . Science : Part A: Polymer Chemistry , 1996 , 34 , 651-658]. There have been studies in which imidization proceeds at a low temperature using amines as base catalysts to obtain polyimides. Examples of the amine base catalysts include triethylamine, pyridine, 1,4-diazabicyclo [2.2.2] octane, , 8-diazabicyclo [5.4.0] undec-7-ene, and the like. When a base catalyst having a low basicity such as triethylamine or pyridine is used, a catalyst having an equivalent amount or more should be used, and at a temperature lower than 200 ° C, there is no imidization acceleration effect. A highly nucleophilic organic base such as 1,4-diazabicyclo [2.2.2] octane has been found to have an imidization effect at low temperatures [M. Ueda, Chem . Lett . 2004 , 33 , 1156-1157]. However, when polyimide is formed with a thick film having a thickness of 10 탆 or more, most of the amine catalyst used is trapped in the resin and remains in the resin . When 1,4-diazabicyclo [2.2.2] octane and 1,8-diazabicyclo [5.4.0] undec-7-ene, which are relatively more basic than the alkylamines, are used as base catalysts, There is a problem that the molecular weight of the polyimide is lowered by promoting the reverse reaction by mixing with acid.

Therefore, a new imidization reaction system which enables imidization even at a low temperature of less than 200 占 폚 is particularly required.

The present inventors have developed a novel catalyst effective for identifying the imidization reaction mechanism and reducing the activation energy required for the dehydration reaction, which is a reaction rate determination step, and have completed the low temperature imidation reaction and applied it as an insulating material for a thin film transistor device.

In general, inorganic thin films having high dielectric constant such as silicon nitride, barium strontium, barium titanate and the like are generally used as insulating materials for thin film transistors. In most cases, There is a disadvantage that expensive vacuum equipment is required for deposition. Thus, US Pat. No. 5,946,551 reports the formation of an inorganic thin film from a precursor of an inorganic thin film by a chemical solution process at a relatively low temperature. In this case, however, a high process temperature of about 300 to 700 ° C. is required, It is difficult to form a thin film on a plastic substrate such as polycarbonate, polysulfone, or polyethersulfone, which is limited to 200 DEG C or less.

Therefore, it is necessary to develop an organic insulator which can not only perform a solution process on a plastic substrate but also provide an electrical stability, an interface characteristic suitable for realizing excellent mobility of an excellent thin film transistor, and an excellent stability over time, Development of a thin film transistor element has been greatly demanded.

In order to solve the above problems, the inventors of the present invention prepared a polyamic acid resin by polymerizing a mixture of (1) an aromatic diamine mixture and (2) a specific aromatic tetracarboxylic acid dianhydride to prepare a polyamic acid resin, The polyimide resin prepared after addition of the catalyst mixture exhibiting a high imidation degree exhibits a high imidization degree of 95% or more, as well as excellent thin film characteristics, and thus the entire organic transistor device manufactured therefrom has low off-current, high It has been confirmed that the device characteristics such as field-effect charge mobility, low hysteresis characteristic, and excellent temporal stability are excellent. Thus, the present invention has been completed.

In addition, the polyimide resin can be processed at a low temperature of 100 to 200 ° C while maintaining almost all the characteristics of the conventional polyimide resin, and the thin film transistor fabricated therefrom has low off-current, high field effect charge mobility, Hysteresis, and good aging stability.

Accordingly, it is an object of the present invention to provide a low-temperature curing polyimide resin having excellent physical properties as a core material for high-tech industries such as an organic thin film transistor and a thin film transistor element into which the polyimide resin and the insulator are introduced.

The present invention solves the above problems by providing an aminoalcohol compound represented by the following formula (2) as a catalyst for imidization reaction.

(2)

Wherein R ₁ , R ₂ , R ₃ and R ₄ each represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms or a hydroxyalkyl group having 1 to 12 carbon atoms, and n is an integer of 0 to 4.

The present invention solves the above problems by providing a method for producing a polyimide resin by imidizing a polyamic acid in the presence of a catalyst, wherein the polyimide resin is produced by using the aminoalcohol compound represented by the formula (1) as a catalyst .

The catalyst of the present invention has the effect of promoting the imidization reaction even at a low temperature of less than 200 캜 by lowering the activation energy required for forming the imide ring from the amic acid group. The catalyst of the present invention has an effect of producing a polyimide having a high molecular weight and a high purity by inhibiting the reverse reaction of converting polyamic acid into acid anhydride and diamine.

The catalyst of the present invention has a low boiling point and is easily removed after the imidization reaction, so that the problem that the catalyst remains in the polyimide is solved.

The polyimide prepared by using the catalyst of the present invention can provide a polyimide resin having a high electric field mobility, a low hysteresis and a little change with time, The organic thin film transistor device using the polyimide to be manufactured also provides a device having excellent characteristics retaining the above characteristics. The organic thin film transistor device using the polyimide of the present invention preferably has a field effect mobility of 1.0 cm ² / Vs or more, a hysteresis of 1.5 or less, and a hysteresis change of 30% or less And exhibits very excellent characteristics.

The polyimide resin to be used in the present invention, which is produced by using the catalyst of the present invention, is a polyamic acid represented by the following formula (1) and a polyimide prepared therefrom.

[Chemical Formula 1]

  In Formula 1,

 ≪ / RTI >

는

The

,

,

,

및

중에서 선택된 1종 이상의 2가기로서, n은 10~1000 범위의 자연수이고; R₁은 각각 탄소수 1~30 사이의 알킬기 또는 아릴기이고; Y는 에스테르기, 아미드기, 이미드기, 및 에테르기 중에서 선택된 하나이다.

,

,

,

And

, N is a natural number ranging from 10 to 1000; R ₁ is an alkyl group or an aryl group each having 1 to 30 carbon atoms; Y is a group selected from an ester group, an amide group, an imide group, and an ether group.

 The polyimide resin of the present invention is preferably a polyimide resin having an intrinsic viscosity of 1.0 to 3.0 g / dL, a weight average molecular weight of 10,000 to 500,000 g / mol, a dielectric constant of 2 to 6, 65 dyne / cm. In the present invention, the polyimide resin is thermally cured at 100 to 200 ° C for 60 to 120 minutes at a low temperature.

The aminoalcohol compound represented by Formula 2 of the present invention is not high in basicity but has a tertiary amine functional group and a hydroxy functional group in one molecule at the same time and these two functional groups are linked to a flexible carbon skeleton, The amine functional group and the hydroxy functional group act effectively at the reaction site, thereby promoting the dehydration cyclization even at a low temperature of less than 200 DEG C, thereby increasing the imidization rate of the polyamic acid. More specifically, the aminoalcohol compound represented by the above formula (2) used as a catalyst in the course of dehydration of hydrogen atoms bonded to nitrogen atoms into water molecules is subjected to a state in which the amine functional group acts as a base to remove the proton , And it can be inferred that the hydroxy function serves to stabilize the anion oxygen atom of the cyclic intermediate through the proton of the hydroxy group. In addition, at the stage where the deprotonation reaction proceeds, it is presumed that the hydroxy functional group acts as a proton donor to promote the dehydration reaction through proton transfer. That is, the amine functional group present in the amino alcohol compound represented by the formula (2) proposed as a catalyst in the present invention acts as a base in the deprotonation reaction, and the hydroxy functional group transfers a proton to the oxygen atom of the cyclic intermediate, And these two functional groups are linked by a flexible carbon chain, and the interval between two operation periods is controlled as the length of the carbon chain to control the imidization reaction.

As the imidization reaction catalyst characterized by the present invention, the amino alcohol compound is represented by the formula_One, R₂, R₃, And R₄Each represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a hydroxyalkyl group having 1 to 12 carbon atoms, and n is an aminoalcohol compound having an integer of 0 to 4. Preferably, in Formula 2, R_One And R₂Each represent an alkyl group having 1 to 12 carbon atoms, R₃ And R₄Each represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a hydroxyalkyl group having 1 to 12 carbon atoms, and n is an aminoalcohol compound having an integer of 0 to 4. As the imidization reaction catalyst, particularly preferably,N, N- dimethylaminoethanol,N, N- diethylaminoethanol,N, N- dimethylaminopropanol,N, N- dimethyl amino butanol,N, N- dimethylaminobutan-2-ol,N, N- dimethylaminobutane-1,2-diol,N, NDiethylaminohexane-1,2-diol, and the like.

In addition, the amino alcohol compound as an imidization reaction catalyst according to the present invention has a low boiling point and can be easily removed even at a low temperature after the imidization reaction. As an example, N, N -dimethylaminoethanol and N, N -diethylaminoethanol are liquid compounds having boiling points of 134 ° C and 161 ° C, respectively. This property is obtained when the catalyst remaining on the film after polyimide resin formation is completely It represents a great advantage in elimination. However, 1,4-diazabicyclo [2.2.2] octane and 1,8-diazabicyclo [5.4.0] undec-7-ene, which have heretofore been used as imidization catalysts, There is a problem that the residual amount of the polyimide resin in the film increases after the polyimide resin is formed.

In addition, the amino alcohol compound as an imidization reaction catalyst characterized by the present invention is able to perform a catalytic action smoothly even though its basicity and nucleophilicity are not high, and also has a low basicity and nucleophilic property, Effective control. That is, 1,4-diazabicyclo [2.2.2] octane and 1,8-diazabicyclo [5.4.0] undec-7-ene, which were conventionally used as imidization catalysts, There is a problem in producing a polyimide resin having a desired molecular weight range by reducing the molecular weight of the polyamic acid due to the reverse reaction of the polyamic acid in which the polyamic acid is dissociated into the acid anhydride and the diamine due to the nucleation.

In addition, the amino alcohol compound as the imidization reaction catalyst of the present invention can be added to a polyamic acid solution and stored. The catalyst of the present invention is a relatively mild amino alcohol compound and exhibits sufficient imidization efficiency without substantially exhibiting decomposition action of polyamic acid. These properties are convenient to use in the polyimide film manufacturing process while storing and storing the catalyst in advance in the polyamic acid solution in the actual polyimide resin manufacturing process. However, since amines used as imidization catalysts are difficult to add to polyamic acid solution and stored, there is a problem in the process of adding and dissolving the polyamic acid solution immediately upon coating the polyamic acid solution on the support.

The amino alcohol compound represented by Formula 2 as an imidization reaction catalyst characterized by the present invention is contained in an amount of 1 to 200% by weight, preferably 1 to 100% by weight, more preferably 5 to 100% by weight, based on the solid content of the polyamic acid. 50% by weight. When the amount of the amino alcohol compound used as the catalyst is less than 1% by weight, the imidization reaction rate is significantly lowered and the effect as a catalyst is insignificant. When the amount of the amino alcohol compound is over 200% by weight, It is preferable to keep the above range.

As described above, the amino alcohol compound represented by Formula 2 according to the present invention has excellent effects as an imidization catalyst, and the catalytic effect can be clearly distinguished from the results of Examples and Comparative Examples have.

The polyimide manufacturing method according to the present invention will be described in more detail as follows.

The polyimide according to the present invention is prepared by imidizing a polyamic acid as is generally well known in the art.

The production method can be specifically described by a casting method in which a polyamic acid solution is applied onto a general support and the imidization is carried out to obtain a polyamide resin in the form of a film. Such a casting method is merely an example, and the present invention is not limited to such a casting method.

At this time, the support is generally used in the art, and can be changed depending on the intended form and parts, and there is no particular restriction on the choice of support in the present invention. Also, although the thickness of the polyimide film to be formed is not limited, films generally in the range of 100 nm to 500 μm are generally used in the art. The reason is that if the thickness of the film is less than 100 nm, it is difficult to act as a thin film, and if it is more than 500 탆, problems arise in forming a uniform film.

The imidization reaction performed by the present invention can be carried out not only at a high temperature of 200 ° C or higher but also at a low temperature of less than 200 ° C, which is generally performed. The imidization reaction of the present invention can be carried out specifically within a wide temperature range of 100 to 400 ° C. That is, it is possible to produce a desired high-quality polyimide resin even at a low temperature of 100 to 200 ° C at which the reaction has not been performed conventionally, and preferably at 100 ° C or more to minimize the amount of residual solvent and catalyst . However, if the imidization reaction temperature is less than 100 占 폚, removal of water dehydrated in the reaction is not smooth, resulting in deterioration of quality such as formation of micropores in the film. When the imidization reaction temperature exceeds 400 占 폚, oxidation and decomposition of the polyimide resin And the resultant resin may be deteriorated in physical properties. Therefore, it is preferable to maintain the above temperature range.

Meanwhile, the polyamic acid used in the method for producing polyimide according to the present invention is generally used for producing polyimide. In the present invention, the selection of polyamic acid is not particularly limited.

In general, polyamic acid is produced by using an aliphatic or aromatic tetracarboxylic acid dianhydride and an aliphatic or aromatic diamine as a raw material. In order to obtain a polyimide having high heat resistance and excellent mechanical properties, an aromatic dianhydride and an aromatic diamine . The tetracarboxylic acid dianhydride is not particularly limited and is commonly used in the art. Specifically, 1,2,3,4-benzenetetracarboxylic dianhydride, which is a wholly aromatic acid dianhydride capable of giving a high packing structure, (Dicarboxyphenylmethane) dianhydride, bis (dicarboxyphenylsulfone) dianhydride, bis (dicarboxyphenylsulfide) dianhydride, bis (dicarboxyphenylmethane) dianhydride, bis Phenyl) propane dianhydride, bis (dicarboxyphenyl) hexafluoropropane dianhydride, biphenyltetracarboxylic dianhydride, naphthalenetetracarboxylic acid dianhydride, fluorine-substituted derivatives thereof and alkyl-substituted derivatives thereof, or a mixture of two or more thereof .

As the diamine, a wholly aromatic diamine may be used. Specific examples of the diamines include p -phenylenediamine, m -phenylenediamine, diaminodiphenyl ether, diaminodiphenylmethane, diaminobiphenyl, diaminodimethylphenyl ether, diamino (Aminophenyl) propane, bis (aminophenyl) hexafluoropropane, diaminodiphenylsulfone, diaminodiphenylsulfone, diaminodiphenylsulfone, diaminodiphenylsulfone, diaminodiphenylsulfone, Bis (aminophenoxy) benzene, 1,3-bis (aminophenoxy) benzene, 1,3-bis (aminophenoxy) benzene, Bis (aminophenoxyphenyl) ether, 2,2-bis (aminophenoxyphenyl) hexene, bis (aminophenoxyphenyl) Diaminobenzenesulfonic acid, 2,4-diaminobenzenesulfonic acid, 4,4-diaminodiphenylamide, 2,5-diaminobenzenesulfonic acid, and 2,2-diaminobenzenesulfonic acid, And a fluorine-substituted derivative thereof and an alkyl-substituted derivative thereof, or a mixture of two or more thereof.

On the other hand, as the other monomer, a diamine monomer containing a low polarity alkyl group may be used. That is, 1- (3,5-diamino-phenyl) -3-alkyl-succinic imide (DA-R _IM-1), 3,5-diamino-phenyl-alkyl-ether (DA-OR _1), 3 (DA-Es-R ₁ ), 3,5-diaminophenyl-alkyl-amide (DA-AM-R ₁ ) alone or a mixture of two or more of them may be used. ₁ is an alkyl or aryl group having 1 to 30 carbon atoms. Particularly, in the present invention, the low polar group-containing diamine monomer can expand the surface tension control range of the polyimide insulator. The diamine monomer containing a low polar group is used in a range of 0 to 100 mol% based on the total amount of the diamine monomer, and the surface energy of the thin film can be controlled depending on the amount of the diamine monomer used.

The reaction of the wholly aromatic acid dianhydride and the diamine is carried out in a solvent capable of dissolving the reactant and the polyamic acid as a target product. The solvent is not particularly limited in the art, but specifically includes tetrahydrofuran, methanol, cyclohexanone, N, N -dimethylformamide, N, N -dimethylacetamide, N -methyl- , Cresol, pyridine, dimethyl sulfoxide,? -Butyrolactone, 2-butoxyethanol, and 2-ethoxyethanol, and the like. The solvent is used in such an amount as to maintain the solid concentration in the range of 1 to 50% by weight, and the temperature and the concentration can be controlled to control the molecular weight of the formed polyamic acid. At this time, the reaction temperature is generally, but not particularly limited to, performed in the range of -20 ° C to 100 ° C. The polyamic acid thus prepared can be used as a solution of a polyamic acid solution to remove a solvent or to contain a solvent.

As suggested by the present invention, when an imidization reaction of a polyamic acid is carried out using an amino alcohol compound represented by the above formula (2) as a reaction catalyst, the imidization rate is 95 to 100% and the residual catalyst amount in the polyimide resin is 0 To 10% by weight.

The polyimide resin according to the present invention has a surface tension of 30 to 65 dyne / cm and a dielectric constant of 2 to 6.

The polyimide resin produced by the above polymerization method has a weight average molecular weight (Mw) in the range of 10,000 to 500,000 g / mol, an intrinsic viscosity in the range of 1.0 to 3.0 g / dl, and a pyrolysis temperature in the range of 400 to 600 ° C. In addition, the chemical resistance of the polyimide resin after curing was greatly improved. In addition, the dielectric constant ranged from 2 to 6 at a frequency of 10 KHz, and the surface tension was found to be in the range of 30 to 65 dyne / cm.

As described above, the polyamic acid resin according to the present invention is a polymer material having improved electrical insulation characteristics as well as imidization reaction at a low temperature process in a temperature range of 100 to 200 ° C by introduction of an appropriate organic catalyst, Is useful as an insulator for all the required organic thin film transistors. In addition, the organic thin film transistor fabricated from these is 0.01 ~ 3.0 cm ² / Vs, preferably from 1 cm ² / Vs or more, even more preferably from a high field-effect charge transfer of 1 ~ 3.0cm ² / Vs range, ^-10 to 10 Off-current characteristics in the range of 10 ^-13 A and hysteresis characteristics of less than 1 V.

Accordingly, it is an object of the present invention to provide an organic thin film transistor element made of a polyimide resin which has excellent physical properties as a core material for an advanced industrial industry such as an organic thin film transistor and is capable of a low temperature process.

The polyimide resin according to the present invention has a weight average molecular weight (Mw) in the range of 10,000 to 500,000 g / mol, an intrinsic viscosity in the range of 1.0 to 3.0 g / dl, a pyrolysis temperature in the range of 450 to 550 DEG C, 6, surface tension in the range of 30 to 65 dyne / cm. Further, it is used as an insulating material for all organic thin film transistors High field-effect charge mobility, off-current characteristics in the range of 10 ^-10 to 10 ^-13 A, and hysteresis characteristics of 1 V or less.

Accordingly, the polyimide resin of the present invention has a low temperature process characteristic in the range of 100 to 200 占 폚 as an insulating material, has excellent electrical properties, chemical resistance and heat resistance, so that it can be used as a buffer insulating layer for a transistor, The organic thin film transistor fabricated from the glass substrate and the liquid crystal display device for a touch panel can not only provide excellent off current characteristics and excellent hysteresis characteristics.

The present invention will now be described more specifically with reference to Examples, but the present invention is not limited by the following Examples

Example  1. Polyimide thin film ( LPI -1) Thin Film Fabrication

10.8 g (0.1 mol) of para-phenylenediamine ( p- PDDA) was dissolved in N -methyl-2-pyrrolidone (NMP) while nitrogen gas was slowly passed through a 100-ml reactor equipped with a stirrer and a nitrogen- , 29.6 g (0.1 mol) of biphthalic dianhydride [BPDA] was slowly added. At this time, the solid content was adjusted to 20 wt%, and the reaction was allowed to proceed for 3 hours while maintaining the reaction temperature at 0 to 10 ° C. The yield of the polymerization reaction was confirmed to be quantitative, and the intrinsic viscosity was measured at 30 ° C at a concentration of 0.5 g / dl with N - methyl - 2 - pyrrolidone as a solvent. To the prepared polyamic acid solution, 4 g of N, N -dimethylaminoethanol (10 wt% based on the solid content of the polyamic acid) was added and stirred for 10 minutes. The mixture was spin-coated and imidized at 160 ° C for 60 minutes. To prepare a polyimide thin film (LPI-1). The thickness of the polyimide thin film was controlled in the range of 1,000 angstroms, and the imidization degree was measured using an FT-IR spectroscope.

Example  2. Polyimide thin films ( LPI -2) Preparation of Thin Films

10.8 g (0.1 mol) of para-phenylenediamine ( p- PDDA) was dissolved in N -methyl-2-pyrrolidone (NMP) while nitrogen gas was slowly passed through a 100-ml reactor equipped with a stirrer and a nitrogen- , Followed by the slow addition of 21.8 g (0.1 mol) of pyromellitic dianhydride [PMDA]. At this time, the solid content was adjusted to 20 wt%, and the reaction was allowed to proceed for 3 hours while maintaining the reaction temperature at 0 to 10 ° C. The yield of the polymerization reaction was confirmed to be quantitative, and the intrinsic viscosity was measured at 30 ° C at a concentration of 0.5 g / dl with N - methyl - 2 - pyrrolidone as a solvent. To the prepared polyamic acid solution, 4 g of N, N -dimethylaminoethanol (10 wt% based on the solid content of the polyamic acid) was added and stirred for 10 minutes. The mixture was spin-coated and imidized at 160 ° C for 60 minutes. To prepare a polyimide thin film (LPI-2). The thickness of the polyimide thin film was controlled in the range of 1,000 angstroms, and the imidization degree was measured using an FT-IR spectroscope.

Example 3: Preparation of polyimide thin film (LPI-3) thin film

14.5 g (0.1 mol) of 3,5-diaminobenzoic acid was dissolved in N -methyl-2-pyrrolidone (NMP) while nitrogen gas was slowly passed through a 100-ml reactor equipped with a stirrer and a nitrogen- 29.6 g (0.1 mol) of biphthalic dianhydride [BPDA] was slowly added. At this time, the solid content was adjusted to 20 wt%, and the reaction was allowed to proceed for 3 hours while maintaining the reaction temperature at 0 to 10 ° C. The yield of the polymerization reaction was confirmed to be quantitative, and intrinsic viscosity was measured at 30 ° C at a concentration of 0.5 g / dl with N - methyl - 2 - pyrrolidone as a solvent. To the prepared polyamic acid solution, 4 g of N, N -dimethylaminoethanol (10 wt% based on the solid content of the polyamic acid) was added and stirred for 10 minutes. The mixture was spin-coated and imidized at 160 ° C for 60 minutes. To prepare a polyimide thin film (LPI-3). The thickness of the polyimide thin film was controlled in the range of 1,000 angstroms, and the imidization degree was measured using an FT-IR spectroscope.

Example  4. Polyimide thin films ( LPI -4) Preparation of thin films

In a 100 ml reactor equipped with a stirrer and a nitrogen injection device, 18.1 g (0.1 mol) of 2,4-diaminobenzenesulfonic acid was dissolved in N -methyl-2-pyrrolidone (NMP) while nitrogen gas was passed slowly , Followed by the slow addition of 29.6 g (0.1 mol) of biphthalic dianhydride [BPDA]. At this time, the solid content was adjusted to 20 wt%, and the reaction was allowed to proceed for 3 hours while maintaining the reaction temperature at 0 to 10 ° C. The yield of the polymerization reaction was confirmed to be quantitative, and the intrinsic viscosity was measured at 30 ° C at a concentration of 0.5 g / dl with N - methyl - 2 - pyrrolidone as a solvent. To the prepared polyamic acid solution, 4 g of N, N -dimethylaminoethanol (10 wt% based on the solid content of the polyamic acid) was added and stirred for 10 minutes. The mixture was spin-coated and imidized at 160 ° C for 60 minutes. To prepare a polyimide thin film (LPI-4). The thickness of the polyimide thin film was controlled in the range of 1,000 angstroms, and the imidization degree was measured using an FT-IR spectroscope.

Example 5. Preparation of polyimide thin film (LPI-5) thin film

In a 100 ml reactor equipped with a stirrer and a nitrogen injection device, 22.4 g (0.1 mol) of 4,4-diaminodiphenylamide was dissolved in N -methyl-2-pyrrolidone (NMP) while nitrogen gas was passed slowly , Followed by the slow addition of 29.6 g (0.1 mol) of biphthalic dianhydride [BPDA]. At this time, the solid content was adjusted to 20 wt%, and the reaction was allowed to proceed for 3 hours while maintaining the reaction temperature at 0 to 10 ° C. The yield of the polymerization reaction was confirmed to be quantitative, and the intrinsic viscosity was measured at 30 ° C at a concentration of 0.5 g / dl with N - methyl - 2 - pyrrolidone as a solvent. To the prepared polyamic acid solution, 4 g of N, N -dimethylaminoethanol (10 wt% based on the solid content of the polyamic acid) was added and stirred for 10 minutes. The mixture was spin-coated and imidized at 160 ° C for 60 minutes. To prepare a polyimide thin film (LPI-4). The thickness of the polyimide thin film was controlled in the range of 1,000 angstroms, and the imidization degree was measured using an FT-IR spectroscope.

Example 6: Preparation of polyimide thin film (LPI-6) thin film

(0.09 mol) of para-phenylenediamine ( p- PDA) and 1- (3,5-diaminophenyl) -3- (3-methylphenyl) propane were slowly passed through a 100 ml reactor equipped with a stirrer and a nitrogen- After dissolving 4.6 g (0.01 mol) of octadecyl-succinimide (DA-IM-18) in N -methyl-2-pyrrolidone (NMP), 29.6 g of biphthalic dianhydride [BPDA] ) Was slowly added. At this time, the solid content was adjusted to 20 wt%, and the reaction was allowed to proceed for 3 hours while maintaining the reaction temperature at 0 to 10 ° C. The yield of the polymerization reaction was confirmed to be quantitative, and the intrinsic viscosity was measured at 30 ° C at a concentration of 0.5 g / dl with N - methyl - 2 - pyrrolidone as a solvent. To the prepared polyamic acid solution, 4 g of N, N -dimethylaminoethanol (10 wt% based on the solid content of the polyamic acid) was added and stirred for 10 minutes. The mixture was spin-coated and imidized at 160 ° C for 60 minutes. To prepare a polyimide thin film (LPI-6). The thickness of the polyimide thin film was controlled in the range of 1,000 angstroms, and the imidization degree was measured using an FT-IR spectroscope.

Example  7

Polyimide resin (LPI-7) was prepared in the same manner as in Example 1 except that 5 wt% of N, N -dimethylaminoethanol was used for the polyamic acid solid component.

Example  8

Instead of N, N -dimethylaminoethanol , 10% by weight of N, N -diethylaminoethanol was introduced into the solid content of polyamic acid and imidization reaction was carried out at a temperature of 150 ° C. for 60 minutes To prepare a polyimide resin (LPI-8).

Example  9

N, N -dimethylaminoethanol was introduced in an amount of 25% by weight based on the solid content of the polyamic acid, imidization was carried out at a temperature of 130 ° C. for 60 minutes to obtain a polyimide resin (LPI-9 ).

Example  10

N, N -dimethylaminoethanol was introduced in an amount of 30% by weight based on the solid content of the polyamic acid, imidization was carried out at a temperature of 100 ° C for 60 minutes to obtain a polyimide resin (LPI-10 ).

Comparative Example  One

1,8-diazabicyclo [5.4.0] undec-7-ene was introduced in an amount of 10% by weight based on the solid content of the polyamic acid, imidization reaction was carried out at a temperature of 200 ° C for 60 minutes To prepare a polyimide resin (LPI-11).

Comparative Example  2. Polyimide ( HPI -1)

10.8 g (0.1 mol) of para-phenylenediamine ( p- PDDA) was dissolved in N -methyl-2-pyrrolidone (NMP) while nitrogen gas was slowly passed through a 100-ml reactor equipped with a stirrer and a nitrogen- , 29.6 g (0.1 mol) of biphthalic dianhydride [BPDA] was slowly added. At this time, the solid content was adjusted to 20 wt%, and the reaction was allowed to proceed for 3 hours while maintaining the reaction temperature at 0 to 10 ° C. The prepared polyamic acid solution was spin-coated and imidized at 160 ° C for 120 minutes to prepare a polyimide thin film (HPI-1). The thickness of the polyimide thin film was controlled in the range of 1,000 angstroms, and the imidization degree was measured using an FT-IR spectroscope.

Comparative Example  3. Polyimide ( HPI -2)

10.8 g (0.1 mol) of para-phenylenediamine ( p- PDDA) was dissolved in N -methyl-2-pyrrolidone (NMP) while nitrogen gas was slowly passed through a 100-ml reactor equipped with a stirrer and a nitrogen- , 29.6 g (0.1 mol) of biphthalic dianhydride [BPDA] was slowly added. At this time, the solid content was adjusted to 20 wt%, and the reaction was allowed to proceed for 3 hours while maintaining the reaction temperature at 0 to 10 ° C. The prepared polyamic acid solution was spin-coated and imidized at 400 ° C for 120 minutes to prepare a polyimide thin film ( HPI- 2) . The thickness of the polyimide thin film was controlled in the range of 1,000 angstroms, and the imidization degree was measured using an FT-IR spectroscope.

The monomer compositions and intrinsic viscosities of the polyamic acid prepared according to Examples 1 to 10 and Comparative Examples 1 and 2 are shown in Table 1 below.

[Table 1]

The soluble polyimide resin of the present invention had an intrinsic viscosity of 1.28 to 2.64 dl / g and a weight average molecular weight of 10,000 to 500,000 g / mol as measured by gel permeation chromatography (GPC). The film moldability Were found to be very good.

Preparation and characterization of polyimide thin films

The polyamic acid solutions prepared in Examples 1 to 10 and Comparative Examples 1 and 2 were spin coated to a thickness of 1000 Å and then heat treated at 90 ° C. for 2 minutes to remove the solvent. Then, the polyimide thin film was dried at a temperature of 100 to 400 ° C. for 60 to 120 minutes.

[Characteristic evaluation of polyimide thin film]

(1) Solubility

 In the present invention, a polyimide thin film was prepared by changing the thermosetting conditions of the polyamic acid solution and the type of the catalyst. After heat treatment at a temperature range of 100 to 400 ° C for 60 to 120 minutes, stability against the porter resist stripper and etchant The evaluation results are shown in Table 2 below.

(2) Thermal properties

In order to examine the thermal properties of the polyimide resin prepared in the present invention, the polyimide resin prepared in Examples 1 to 10 and Comparative Examples 1 to 3 was heat-treated at a temperature of 100 to 400 ° C., To determine the initial decomposition temperature. Also, HPLC was used to measure the residual amount of catalyst remaining in the thin film, and the results are shown in Table 2 below.

[Table 2]

As can be seen from Table 2 above, the polyimide resins prepared according to Examples 1 to 10 of the present invention exhibited excellent photoresist removers and ITO, even though the imidization reaction proceeded at a low temperature ranging from 100 to 200 ° C. And showed excellent solvent resistance not dissolving in the cantilever, which is equivalent to that of HPI-2 subjected to the reaction at a high temperature of 400 ° C. On the other hand, HPI-1, which was cured at a temperature of 200 ° C without using a catalyst, was completely dissolved in the solution. In addition, in the case of the catalyst residual amount measured by HPLC, the residual amount of catalyst existing in the thin film of the present invention was as low as 200 ppm or less, while the 1,8-diazabicyclo [5.4.0] Undec-7-ene as a catalyst showed a high value of more than 2000 ppm. The polyimide films of Examples 1 to 10 exhibited high pyrolysis temperatures ranging from 480 to 550 ° C. The results are shown in Table 3 below.

(3) Evaluation of surface energy and dielectric constant

[Dielectric constant]

In order to measure the dielectric constant of the polyimide thin films prepared in Examples 1 to 10 and Comparative Examples 1 to 3, gold of 40 nm thickness was thermally deposited on a glass substrate under a vacuum of 10 ^-6 torr. The polyimide solution was spin-coated to a thickness of 3000 to 5000 Å, and then heat-treated at 90 ° C for 2 minutes to remove the solvent. Then, it was dried at a temperature of 120 to 400 DEG C for 60 to 120 minutes. On the obtained polyimide thin film, gold of 2 cm in diameter was deposited to a thickness of 40 nm, and dielectric constant was measured at a frequency of 10 kHz using an impedance analyzer.

[Table 3]

(4) Organic thin film transistor characteristics

The organic thin film transistor was fabricated using the low temperature curable polyimide of the present invention and its characteristics were measured. As organic semiconductors, Pentacene, which is most widely used in organic thin film transistors and has relatively good performance, was used. A plastic substrate such as glass or polyethersulfone was used as the substrate. The top-contact device fabrication method is as follows.

First, the cleanliness of the substrate is one of the most important factors when manufacturing an electronic device. Therefore, the substrate cleaned by ultrasonic cleaning using a detergent, distilled water, acetone, and isopropyl alcohol and sufficiently dried in an oven was used. Only the protective film was removed without using the process and used as it was. A 2 mm wide gate electrode was formed to a thickness of 40 nm on a well-cleaned substrate by thermal vacuum deposition at a vacuum of 1 × 10 ^-6 torr using a shadow mask. The polyamic acid solution of the present invention was spin-coated thereon to a thickness of 50 to 500 nm, dried at 90 ° C for 2 minutes, and imidized at 100-200 ° C. Pentacene, an organic semiconductor, was deposited on the polyimide insulating film to a thickness of 30 to 100 nm by thermal vacuum deposition at a vacuum of 1 × 10 ^-6 torr. At this time, the temperature of the substrate, which greatly influences the crystallization of pentacene, was kept constant at 90 to 140 ° C. Finally, gold was deposited to a thickness of 40 nm by the same method as gate deposition to form the source and drain electrodes. The bottom-contact device was fabricated by changing the order of forming pentacene, source and drain electrodes. The characteristics of the device fabricated as described above were measured by measuring the gate voltage-drain current curves corresponding to the drain voltage-drain current and the drain voltage according to the gate voltage using E5272 equipment manufactured by Agilent Technologies, Current, and voltage.

 The characteristics of the organic thin film transistor are summarized and the results are shown in Table 4 below.

[Off current characteristics, electric field charge mobility and hysteresis characteristics]

As can be seen from the following Table 4, the polyimide resins prepared according to Examples 1 to 10 of the present invention had dielectric constants in the range of 2.0 to 6.0 and surface energies in the range of 30 to 65 dyne / cm, The lowest dielectric constant and surface energy were shown for LPI-6 with DA-L-18IM, a monomer containing side chain groups. In addition, the increase of the imidization degree and the decrease of the surface energy showed the effect of increasing the field effect charge mobility, and as a result, it showed a good field effect charge mobility.

[Table 4]

1 is a transistor characteristic (out put curve) of an organic thin film transistor element in which LPI-2 prepared in Example 2 is introduced as an insulator,

2 is a hysteresis curve of an organic thin film transistor element in which LPI-2 prepared in Example 2 is introduced as an insulator.

Claims (13)

And a residual amount of catalyst in the polyimide resin is 0 to 156 ppm, and the electric field effect carrier mobility on the organic thin film transistor device manufactured using the polyimide resin is 1 to 3.0 cm < 2 > / Vs. [Chemical Formula 1]

[Formula 1]

 ≪ / RTI >

The

,

,

,

And

, N is a natural number ranging from 10 to 1000; R ₁ is an alkyl group or an aryl group each having 1 to 30 carbon atoms; And Y is a group selected from an ester group, an amide group, an imide group, and an ether group. (2)

Wherein R ₁ and R ₂ are each an alkyl group having 1 to 12 carbon atoms, R ₃ and R ₄ are each a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a hydroxyalkyl group having 1 to 12 carbon atoms, n is an integer of 0 to 4.]  The method according to claim 1, Wherein the polyimide resin has an intrinsic viscosity of 1.0 to 3.0 g / dL and a weight average molecular weight of 10,000 to 500,000 g / mol.  The method according to claim 1, Wherein the polyimide resin has a dielectric constant of 2 to 6.  The method according to claim 1, Wherein the polyimide resin has a surface tension of 30 to 65 dyne / cm.  The method according to claim 1, Wherein the polyimide resin is thermally cured at 100 to 200 DEG C for 60 to 120 minutes. delete delete The method according to claim 1, Wherein the compound of Formula 2 is selected from the group consisting of N, N -dimethylaminoethanol, N, N -diethylaminoethanol, N, N -dimethylaminopropanol, N, N -dimethylaminobutanol, N, , N, N -dimethylaminobutane-1,2-diol, and N, N -diethylaminohexane-1,2-diol. An organic thin film transistor device manufactured using the polyimide resin of claim 1 and having an off current of 10 ^-10 to 10 ^-13 A. 10. The method of claim 9, Wherein the device has a hysteresis of 1 V or less. A process for producing a low-temperature curing polyimide resin, comprising the steps of: preparing a polyimide by imidizing a polyamic acid by using an amino alcohol compound represented by the following formula (2) as a catalyst, wherein the catalyst residual amount in the polyimide resin is 0 to 156 ppm. (2)

Wherein R ₁ and R ₂ are each an alkyl group having 1 to 12 carbon atoms, R ₃ and R ₄ are each a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a hydroxyalkyl group having 1 to 12 carbon atoms, n is an integer of 0 to 4.] delete 12. The method of claim 11, Wherein the imidization is performed by heating at a low temperature of 100 to 200 占 폚.

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