KR20190081459A - Method of preparing Polyamic acid and Polyamic acid, Polyimide resin and Polyimide film thereby - Google Patents

Abstract

The present invention relates to a method for manufacturing a polyamic acid, and the polyamic acid, a polyimide resin, and a polyimide film manufactured from the same. Specifically, the present invention relates to the development of a polyimide composition in which a linear thermal expansion coefficient of the polyimide film manufactured from the same is improved by changing to a method of dividing and inputting when putting a single diamine.

Description

[0001] The present invention relates to a method for producing polyamic acid, a polyamic acid, a polyimide resin and a polyimide film produced therefrom,

The present invention relates to a process for producing a polyamic acid, a polyamic acid, a polyimide resin and a polyimide film produced therefrom.

In general, a polyimide (PI) film is a film made of a polyimide resin, and a polyimide resin is produced by solution polymerization of an aromatic dianhydride and an aromatic diamine or aromatic diisocyanate to prepare a polyamic acid derivative, Refers to a high heat-resistant resin produced by imidization.

Since such a polyimide film has excellent mechanical, heat resistance and electrical insulation properties, it is used in a wide range of electronic materials such as a semiconductor insulating film, a substrate for an electrode protection film flexible printed wiring circuit of a TFT-LCD, and the like.

 However, the polyimide resin is colored in brown and yellow due to its high aromatic ring density, and thus has low transmittance in the visible light region and yellowish color to lower the light transmittance and has a large birefringence, making it difficult to use the polyimide resin as an optical member have.

U.S. Patent Nos. 4595548, 4603061, 4645824, 4895972, 5218083, 5093453, 5218077, 5367046, 5338826. 5986036 and 6232428 and Korean Patent Laid-Open Publication No. 2003-0009437 disclose monomers having a backbone structure connected to a linking group such as -O-, -SO ₂ -, or CH ₂ - and the like at an m-position other than the p-position There has been reported a novel structure of polyimide having improved transparency and color transparency as far as the thermal property is not significantly deteriorated by using aromatic dianhydride dianhydride and aromatic diamine monomer having a substituent such as -CF ₃ , It is inadequate for use as a display element material for OLED, TFT-LCD, and flexible display in terms of mechanical properties, heat resistance and birefringence.

The present invention relates to a method for producing a polyamic acid having an improved linear thermal expansion coefficient while maintaining the same raw materials and the same amount of an existing composition but changing the method of injection to maintain the optical properties and a polyamic acid, a polyimide resin and a polyimide film And an image display device including the same.

One preferred embodiment of the present invention is a process for the preparation of a mixture of a diamine and a pyromellitic dianhydride including 1,2,4-benzene tetracarboxylic acid (2,2'-bis (trifluoromethyl) benzidine, TFDB) dianhydride, < RTI ID = 0.0 > PMDA) < / RTI > Bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA), and diamines including 2,2'-bis (trifluoromethyl) And a dianhydride containing at least one selected from 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA), and a process for producing the polyamic acid. .

And the molar ratio of at least one selected from PMDA to 6FDA and BPDA is 90 to 25:10 to 75.

And the molar ratio of PMDA to 6FDA is 90 to 70: 10 to 30.

Wherein the molar ratio of PMDA to BPDA is 90 to 25: 10 to 75.

The molar ratio of PMDA to 6FDA to BPDA is 90 to 50: 5 to 30: 5 to 20.

The diamine may be selected from the group consisting of 9,9-bis (4-aminophenyl) fluorene (FDA) and 9,9-bis (3-fluoro- , And the like.

(9,9-bis (4-aminophenyl) fluorene, FDA) and 9,9-bis (3-fluoro-4-aminophenyl) fluorene And at least one of them is added in an amount of 1 mol% to 20 mol% based on the total molar amount of the diamine.

In another preferred embodiment of the present invention, the repeating unit derived from 2,2'-bis (trifluoromethyl) benzidine (TFDB) and the repeating unit derived from pyromellitic dianhydride (1,2,4,5- bis (trifluoromethyl) benzidine (TFDB), and a repeating unit derived from 2,2-bis (3-methylphenyl) benzene tetracarboxylic dianhydride , 4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA), and 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA). Wherein the polyamic acid comprises a block structure comprising repeating units.

And the molar ratio of at least one selected from the group consisting of 6FDA and BPDA in the second block structure to the PMDA in the first block structure is 90 to 25:10 to 75.

Wherein the molar ratio of PMDA in the first block structure to 6FDA in the second block structure is 90 to 70: 10 to 30.

Wherein the molar ratio of PMDA in the first block structure to BPDA in the second block structure is 90 to 25: 10 to 75.

The molar ratio of PMDA in the first block structure to 6FDA in the second block structure to BPDA in the second block structure is 90 to 50: 5 to 30: 5 to 20.

The block structure containing repeating units derived from bis TFDB and repeating units derived from at least one selected from 6FDA and BPDA is composed of 9,9-bis (4-aminophenyl) fluorene (FDA) and (9,9-Bis (3-fluoro-4-aminophenyl) fluorene, and FFDA).

The content of at least one selected from FDA and FFDA is 1 mol% to 20 mol% based on the total molar amount of diamine.

Another preferred embodiment of the present invention is to provide a polyimide resin produced from the above-mentioned polyamic acid.

Another preferred embodiment of the present invention is to provide a polyimide film made of the polyimide resin.

The polyimide film is characterized by having a coefficient of thermal expansion of 30 ppm / ° C or less at 50 to 350 ° C, a transmittance of 85% or more at 550 nm when measured by a UV spectrometer, and a yellowness of 10 or less .

Another preferred embodiment of the present invention is to provide an image display device including a polyimide film.

According to the present invention, it is possible to provide a method for producing a polyamic acid having an improved linear thermal expansion coefficient while maintaining a yellowness and a transmittance after forming a film or a film, and a polyamic acid, a polyimide resin and a polyimide film produced therefrom.

According to one embodiment of the present invention, diamines including 1,2-bis (trifluoromethyl) benzidine (TFDB) and pyromellitic dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA); Bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA), and diamines including 2,2'-bis (trifluoromethyl) And a dianhydride containing at least one selected from 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA), and a process for producing the polyamic acid. do.

In the present invention, one kind of diamine can be added under one or more conditions, for example, primary and secondary, under specific conditions, and the linear thermal expansion coefficient can be improved while keeping the optical characteristics at a good level.

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

In the method for producing a polyamic acid according to an embodiment of the present invention, a diamine containing pyrazolinic dianhydride (1,2, 3, 4, 5, 6, 7, 4,5-benzene tetracarboxylic dianhydride, PMDA); Bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA), and diamines including 2,2'-bis (trifluoromethyl) And a dianhydride containing at least one selected from the group consisting of biphenyltetracarboxylic dianhydride (BPDA) and biphenyltetracarboxylic dianhydride (BPDA) .

The molar ratio of at least one selected from the PMDA to 6FDA and BPDA is preferably 90 to 25:10 to 75, and more preferably 90 to 30:10 to 70.

When at least one selected from the above-mentioned PMDA, 6FDA and BPDA is out of the above-mentioned molar ratio range, there may be a problem that it has a yellowness degree of 10 or more or a thermal expansion coefficient of 30 ppm / DEG C or more.

(1,2,4,5-benzene tetracarboxylic dianhydride, PMDA) comprising the above-mentioned bis (trifluoromethyl) benzidine (TFDB) And a diamine containing 2,2-bis (trifluoromethyl) benzidine (TFDB) and 2,2-bis (3,5-bis , 4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA), and 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA). The step of introducing dianhydride may be termed a second input, but this is not intended to limit the order of input, but merely to distinguish the input step.

In this case, when two or more kinds of at least one selected from 6FDA and BPDA are added during the second addition, it means that the total molar amount of dianhydride at the second addition is added to the PMDA at the first injection .

When 6FDA is selected from at least one of 6FDA and BPDA at the time of the second charging, the molar ratio of 6FDA at the time of the first charging to the amount of 6FDA at the time of the second charging is 90 to 70:10 to 30, And preferably 90 to 75: 10 to 25.

If the ratio of PMDA is higher than the above range when the PMDA at the first charging and the 6FDA at the second charging are out of the above-mentioned molar ratio range, the linear thermal expansion coefficient may be very low, but the yellowing degree may be very high. If it is higher than this range, the yellowness index is very low, but the linear thermal expansion coefficient may increase.

When BPDA is selected and added in at least one of 6FDA and BPDA at the time of the second charging, the molar ratio of the BPDA at the time of the first charging to the BPDA at the time of the second charging is 90 to 25:10 to 75, And preferably from 85 to 30: 15 to 70. [

If the ratio of PMDA is higher than the above range, the linear thermal expansion coefficient may be very low, but the yellowness may become very high. If the ratio of BPDA If it is higher than this range, the yellowness of PMDA is lowered, but the linear thermal expansion coefficient may be increased.

In one embodiment of the present invention, when more than one kind of at least one selected from 6FDA and BPDA is input at the time of the second input, the PMDA at the first input, the 6FDA at the second input, and the BPDA Is in the range of 90 to 50: 5 to 30: 5 to 20.

There may be a problem of having a yellowness degree of 10 or more or a thermal expansion coefficient of 30 ppm / [deg.] C or more when the PMDA at the first charging and the 6FDA and BPDA at the second charging are out of the above-mentioned molar ratio range.

In the present invention, it is preferable that the dianhydride containing at least one selected from the group consisting of 6FDA and BPDA is added to the dianhydride containing the PMDA, The thermal expansion coefficient and the yellowness degree can be improved at the same time.

That is, in one embodiment of the present invention, diamines including 1,2-bis (trifluoromethyl) benzidine (TFDB) and pyromellitic dianhydride (1,2,4,5-benzene tetramarboxylic dianhydride (PMDA) and diamines including 2,2'-bis (trifluoromethyl) benzidine (TFDB) and 2,2-bis (3,4 (Biphenyltetracarboxylic dianhydride, BPDA), which is a dianhydride containing at least one member selected from the group consisting of dihydrocarbyl, dihydrocarbyl, dicarboxyphenyl, hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride It is preferable to add the rides later in that the physical properties of the present invention can be further improved.

In addition, the diamine at the time of the second addition may be 9,9-Bis (4-aminophenyl) fluorene, FDA and 9,9-Bis (3-fluoro-4 -aminophenyl) fluorene, and FFDA) may be further added. When at least one selected from the above FDA and FFDA is further added, an effect of improving the glass transition temperature can be obtained.

It is preferable that at least one selected from the above FDA and FFDA is contained in an amount of 1 mol% to 20 mol%, preferably 1 to 10 mol%, based on the total molar amount of diamine. When the content of the at least one selected from the above FDA and FFDA is out of the above range, the content is less than 1 mol% and the glass transition temperature may not be improved. When the content is more than 20 mol%, the yellowness and thermal expansion coefficient .

According to one embodiment of the present invention, the diamine containing the secondary addition and containing bis (trifluoromethyl) benzidine (TFDB) and 2,2-bis (3,4- Dianhydride comprising at least one member selected from dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA) and 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA) May be carried out in a third step.

The diamine and dianhydride at the time of the third addition may be appropriately adjusted within the range of the molar ratio of the diamine and the dianhydride at the time of the first and second additions.

In addition to TFDB, FDA and FFDA as the diamine used in one embodiment of the present invention, oxydianiline (ODA), para-phenylene diamine (pPDA), m-phenylenediamine (meta-phenylene diamine, mPDA), p-methylene dianiline (pMDA), m-methylene dianiline (mMDA), bisaminophenoxybenzene bis (4-aminophenoxy) benzene, 133APB), 1,3-bis (4-aminophenoxy) benzene, 134APB, bisaminophenoxyphenylhexafluoropropane aminophenoxy) phenyl] hexafluoropropane, 4BDAF, 2,2'-bis (3-aminophenyl) hexafluoropropane, 33-6F, bisaminophenylhexafluoropropane 4-aminophenyl) hexafluoropropane, 44-6F, bis (4-aminophenyl) sulfone, bis (3-aminophenyl) sulfone and 3-DDS, cyclohexanediamine -Cyclo hexanediamine, 13CHD), 1,4-cyclohexanediamine, 14CHD, 2,2-Bis [4- (4-aminophenoxy) -phenyl] propane, 6HMDA), bisaminodihydroxy Bis (3-amino phenoxy) diphenyl sulfone, 6-aminophenoxy diphenyl sulfone, 6FAP, DBSDA), but the present invention is not limited thereto.

The dianhydride used in the present invention may contain, in addition to PMDA, 6FDA and BPDA, 4- (2,5-dioxotetrahydrofuran-3-yl) -1,2,3,4-tetrahydronaphthalene- 2-dicarboxylic anhydride (TDA), benzophenone tetracarboxylic dianhydride (BTDA), 4,4-oxydiphthalic dianhydride , ODPA), bis (3,4dicarboxyphenyl) dimethyl-silane dianhydride (SiDA), bisdicarboxyphenoxydiphenylsulfide dianhydride (4,4-bis (3,4-dicarboxyphenoxy ) diphenyl sulfide dianhydride (BDSDA), sulfonyldiphthalic anhydride (SO ₂ DPA), cyclobutane-1,2,3,4-tetracarboxylic dianhydride (CBDA) Isopropylidene is phenoxybisphthalic anhydride (4 , 4 '- (4,4'-Isopropylidenediphenoxy) bis (phthalic anhydride), 6HBDA), and the present invention is not limited thereto.

In one embodiment of the present invention, the above-mentioned diamine and dianhydride components are involved in the polymerization reaction.

The conditions for the reaction are not particularly limited, but the reaction temperature is preferably 0 to 80 ° C, and the reaction time is preferably 2 to 48 hours. It is more preferable that the atmosphere is an inert gas atmosphere such as argon or nitrogen during the reaction.

The organic solvent for the solution polymerization of the monomers is not particularly limited as long as it is a solvent dissolving the polyamic acid. As known reaction solvents there may be used m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), acetone, (DEF), diethylacetamide (DEA), propylene glycol monomethyl ether (PGME), propylene glycol monomethyl ether acetate (PGMEA), ethyl lactate, 3-methoxy-N, N-dimethylpropionamide and 3-butoxy-N , And N-methylpropionamide. In addition, a low boiling point solution such as tetrahydrofuran (THF), chloroform or a low-absorbency solvent such as? -Butyrolactone may be used. But the solvent is not limited to those mentioned above, and these solvents may be used alone or in combination of two or more.

The content of the organic solvent is preferably 50 to 95% by weight, more preferably 70 to 90% by weight in the total polyamic acid solution in order to obtain the molecular weight and viscosity of an appropriate polyamic acid solution, Is more preferable.

According to another embodiment of the present invention, there is provided a process for preparing a copolymer comprising repeating units derived from bis (trifluoromethyl) benzidine (TFDB) and pyromellitic dianhydride (1,2,4,5 (2,2'-bis (trifluoromethyl) benzidine (TFDB)) and a second block structure containing a repeating unit derived from 2,2'-bis (tetrabutylammonium) benzene tetracarboxylic dianhydride At least one selected from bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA) and 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA) And a second block structure including a repeating unit derived from the polyamic acid.

The polyamic acid is preferably produced by the above-described production method.

The polyamic acid prepared by the above-mentioned method can be prepared by adding one diamine in one portion so as to contain a first block structure and a second block structure containing one diamine in a specific amount, It is possible to obtain an effect of improving the linear thermal expansion coefficient without lowering the yellowness and permeability as compared with polyamic acid.

The molar ratio of at least one selected from the group consisting of 6FDA and BPDA in the second block structure to the PMDA in the first block structure is 90 to 25:10 to 75, preferably 90 to 30:10 to 70.

If at least one of PMDA in the first block structure and 6FDA and BPDA in the second block structure is out of the molar ratio range, it may have a yellowness degree of 10 or more or a thermal expansion coefficient of 30 ppm / have.

It is also preferable that the molar ratio of PMDA in the first block structure to 6FDA in the second block structure is 90 to 70: 10 to 30, preferably 90 to 75: 10 to 25.

If PMDA in the first block structure and 6FDA in the second block structure are out of the molar ratio range, if the ratio of PMDA is higher than the range, the linear thermal expansion coefficient may be very low, but the yellowness may be very high. Is higher than the range, the yellowness degree is very low, but the linear thermal expansion coefficient may increase.

The molar ratio of the PMDA in the first block structure to the BPDA in the second block structure is preferably 90 to 25:10 to 75, and more preferably 85 to 30:15 to 70.

If the ratio of PMDA in the first block structure and the BPDA in the second block structure deviate from the above-mentioned molar ratio range, the linear thermal expansion coefficient may be very low but the yellowness may be very high. If BPDA Is higher than the range, the yellowness degree of PMDA is lowered, but the linear thermal expansion coefficient may be increased.

In one embodiment of the present invention, the molar ratio of PMDA in the first block structure to 6FDA in the second block structure to BPDA in the second block structure is 90 to 50: 5 to 30: 5 to 20, More preferably from 55: 5 to 30: 5 to 15.

When the PMDA in the first block structure and the 6FDA and BPDA in the second block structure are out of the molar ratio range, there may be a problem of having a yellowness degree of 10 or more or a thermal expansion coefficient of 30 ppm /

Also, the block structure containing repeating units derived from bis TFDB and repeating units derived from at least one selected from 6FDA and BPDA may be a 9,9-bis (4-aminophenyl) fluorene, FDA ) And bis (4-fluoro-4-aminophenyl) fluorene (FFDA). When at least one selected from the above-mentioned FDA and FFDA is further contained, an effect of improving the glass transition temperature can be obtained.

It is preferable that at least one selected from the above FDA and FFDA is contained in an amount of 1 mol% to 20 mol%, preferably 1 to 10 mol, based on the total molar amount of diamine. When the content of the at least one selected from the above FDA and FFDA is out of the above range, the content is less than 1 mol% and the glass transition temperature may not be improved. When the content is more than 20 mol%, the yellowness and thermal expansion coefficient .

The method for producing the polyimide resin by imidizing the polyamic acid described above is not particularly limited, and conventionally known methods can be used. As the imidization method of the polyamic acid, a thermal imidation method, a chemical imidization method, a thermal imidation method and a chemical imidation method may be used in combination, and it is more preferable to use a heat imidation method. More preferably, the solution subjected to the chemical imidation method is subjected to precipitation, followed by purification, drying, and then dissolving in a solvent. This solvent is the same as the above-mentioned solvent. In the chemical imidization method, a dehydrating agent represented by an acid anhydride such as acetic anhydride and a imidization catalyst represented by tertiary amines such as isoquinoline, p-picoline, and pyridine are applied to a polyamic acid solution. The thermal imidation method can be used in combination with the chemical imidization method, and the heating conditions can be varied depending on the type of the polyamic acid solution, the thickness of the film, and the like.

According to another embodiment of the present invention, there is provided a polyimide film made of the polyimide resin.

The polyimide film is obtained by imidizing the obtained polyamic acid solution, adding the imidized solution to a second solvent, precipitating, filtering and drying to obtain a solid component of the polyimide resin, 1 < / RTI > solvent dissolved in a solvent.

That is, the above-mentioned polyamic acid is formed into a polyimide resin by a chemical imidization method, followed by precipitation, drying, dissolution in a solvent, and dissolution into a solvent to be applied to a support film. The solution is filmed on the support by dry air and heat treatment.

The first solvent may be the same solvent as the solvent used in the polyamic acid solution polymerization. The second solvent may be one having a lower polarity than that of the first solvent in order to obtain a solid content of the polyamic acid resin, Alcohols, ethers, and ketones. At this time, the content of the second solvent is not particularly limited, but is preferably 5 to 20 times by weight of the polyamic acid solution.

The film-forming temperature condition of the applied film is preferably 250 to 500 ° C, and a glass plate, an aluminum foil, a circulating stainless belt, a stainless steel drum, or the like can be used.

The time required for film formation varies depending on the temperature, the type of the support, the amount of the applied polyamic acid solution, and the mixing conditions of the catalyst, and is not limited to a certain time. Preferably in a range of 5 minutes to 30 minutes.

 The heat treatment temperature is in the range of 100 to 500 ° C. and the treatment time is 1 to 30 minutes. After the drying and imidization are completed by heat treatment, the support is peeled off.

The thickness of the obtained polyimide film is not particularly limited, but is preferably in the range of 10 to 250 탆, more preferably 10 to 100 탆.

 The polyimide film produced in the present invention preferably has a coefficient of thermal expansion of 30 ppm / ° C or less at 50 to 350 ° C.

The polyimide film produced in the present invention preferably has a transmittance of 85% or more, preferably 90% or more at 550 nm when measuring the transmittance with a UV spectrometer based on a thickness of 10 to 100 탆.

The polyimide film preferably has a yellowing degree of 10 or less, preferably 5 or less, based on a film thickness of 10 to 100 탆.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited to the following Examples.

≪ Example 1 >

273.882 g of N-methyl-2-pyrrolidone (NMP) was charged while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, and then TFDB 28.821 was dissolved. g, and the mixture was stirred for 3 hours. Then, 3.202 g of TFDB was further dissolved, and then 4.443 g of 6FDA was added, followed by reaction for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

≪ Example 2 >

284.922 g of N-methyl-2-pyrrolidone (NMP) was charged while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 25.618 g of TFDB was dissolved, And the mixture was stirred for 3 hours. Thereafter, 6.405 g of TFDB was further dissolved, and 8.885 g of 6FDA was added thereto, followed by reaction for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

≪ Example 3 >

Into a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser was charged with 295.963 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen, 22.416 g of TFDB was dissolved therein, And the mixture was stirred for 3 hours. After the addition of 9.607 g of TFDB, 13.328 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Example 4>

Nitrogen was passed through a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, and 295.963 g of N-methyl-2-pyrrolidone (NMP) was charged. After 9.607 g of TFDB was dissolved, And the mixture was stirred for 3 hours. Thereafter, 22.416 g of TFDB was further dissolved, and 15.268 g of PMDA was added thereto, followed by reaction for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

&Lt; Example 5 >

N-methyl-2-pyrrolidone (NMP) was charged in a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, nitrogen was passed through the reactor, and 16.012 g of TFDB was dissolved. 10.906 g was added thereto, followed by stirring for 3 hours. Thereafter, 16.012 g of TFDB was further dissolved, and 14.711 g of BPDA was added thereto, followed by reaction for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 ° C for 20 minutes, reached 350 ° C, and was cured by isothermal treatment for 10 minutes. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

&Lt; Example 6 >

Nd, N-dimethylacetamide (DMAc) 283.076 g was charged into a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, nitrogen was passed through the reactor and 13.450 g of TFDB was dissolved. And the mixture was stirred for 3 hours. After that, 23.825 g of TFDB and 1.384 g of FFDA were dissolved, and then 22.949 g of BPDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid concentration of 20% by weight was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 ° C for 20 minutes, reached 350 ° C, and was cured by isothermal treatment for 10 minutes. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

&Lt; Example 7 >

N-methyl-2-pyrrolidone (NMP) 288.638 was charged while passing nitrogen through a 500-ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 22.416 g of TFDB was dissolved, and PMDA 15.268 g, and the mixture was stirred for 3 hours. After that, 9.607 g of TFDB was further dissolved, and then 8.885 g of 6FDA was added and reacted for 3 hours. Finally, 2.942 g of BPDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

&Lt; Example 8 >

N-methyl-2-pyrrolidone (NMP) 288.638 was charged while passing nitrogen through a 500-ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 22.416 g of TFDB was dissolved, and PMDA 15.268 g, and the mixture was stirred for 3 hours. Then, 6.405 g of TFDB was further dissolved, and 8.885 g of 6FDA was added thereto, followed by reaction for 3 hours. Finally, after dissolving 3.202 g of TFDB, 2.942 g of BPDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

&Lt; Comparative Example 1 &

Into a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 268.362 g of N-methyl-2-pyrrolidone (NMP) was charged while passing nitrogen, 32.023 g of TFDB was dissolved, And the mixture was stirred for 3 hours. Then 2.221 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

&Lt; Comparative Example 2 &

Into a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser was charged with 295.963 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen, 32.023 g of TFDB was dissolved, And the mixture was stirred for 3 hours. Then, 13.328 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

&Lt; Comparative Example 3 &

Into a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser was charged with 295.963 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen, 32.023 g of TFDB was dissolved, And the mixture was stirred for 3 hours. Then, 15.268 g of PMDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

&Lt; Comparative Example 4 &

Into a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 301.483 g of N-methyl-2-pyrrolidone (NMP) was charged while passing nitrogen, 32.023 g of TFDB was dissolved, And the mixture was stirred for 3 hours. After that, 15.549 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid concentration of 17 wt% was obtained. After the completion of the reaction, the obtained solution was coated on a glass plate, treated with hot air at 80 DEG C for 20 minutes, reached to 370 DEG C, is isothermalized for 30 minutes, and cured. Thereafter, the film was gradually cooled and separated from the glass plate to obtain a polyimide film.

The properties of the polyimide films prepared in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Table 1 below.

(1) Measurement of permeability (TT)

The transmittance was measured three times at 550 nm using a UV spectrometer (Kotikaminolta CM-3700d) and the average values are shown in Table 1.

(2) Yellowness (Y.I.) measurement

Yellowness was measured according to ASTM E313 standard using a UV spectrometer (Konita Minolta, CM-3700d).

(3) Coefficient of thermal expansion (CTE) measurement

The linear thermal expansion coefficient at 50 ~ 350 ° C was measured twice using TMA (TA Instrument, Q400) according to the TMA method. The size of the specimen was 4 mm × 24 mm, the load was 0.02 N, and the temperature raising rate was 10 ° C./min. Since the residual stress may remain in the film through the film formation and heat treatment, the residual stress is completely removed in the first run and the second value is presented as the measured value.

number Raw material ratio and input order film
Thickness (㎛) result YI TT CTE room
city
Yes One TFDB 90 - PMDA 90 -
-TFDB (10) -6FDA (10) 10 9.24 87.93 -6.08 2 TFDB 80 - PMDA 80 -
-TFDB (20) -6FDA (20) 11 8.12 88.04 8.03 3 The TFDB 70 - the PMDA 70 -
-TFDB (30) -6FDA (30) 10 6.76 88.79 23.28 4 TFDB (30) -6FDA (30)
The TFDB 70 - the PMDA 70 - 10 7.76 88.93 28.92 5 TFDB 50-PMDA 50,
-TFDB (50) -BPDA (50) 11 6.72 87.18 1.55 6 TFDB (35) -PMDA (35)
-TFDB (62) -FFDA (3) -BPDA (65) 10 4.63 87.87 8.22 7 The TFDB 70 - the PMDA 70 -
-TFDB (30) -6FDA (20) -BPDA (10) 10 7.08 88.37 14.29 8 The TFDB 70 - the PMDA 70 -
-TFDB (20) -6FDA (20)
-TFDB (10) -BPDA (10) 10 7.11 88.36 11.29 ratio
School
Yes One The TFDB (100)
-PMDA (95) -6FDA (5) 11 10.90 87.63 -11.16 2 The TFDB (100)
-PMDA (70) -6FDA (30) 10 6.96 88.87 31.51 3 The TFDB (100)
-6FDA (30) -PMDA (70) 10 7.32 89.20 30.31 4 The TFDB (100)
-PMDA (65) -6FDA (35) 10 6.34 89.55 46.74

As shown in Table 1, when Examples and Comparative Examples are compared with each other, in Examples 1 to 8 in which TFDB is dividedly introduced, both of the yellowness degree, the transmittance and the linear thermal expansion coefficient are satisfactory, And Comparative Examples 2 to 4 showed properties that the linear thermal expansion coefficient was remarkably lowered.

From these results, it can be seen that Examples 1 to 8 overcome the trade-off relationship between yellowness and linear thermal expansion coefficient by dividing TFDB.

When the primary dianhydride is PMDA and the secondary dianhydride is 6FDA, the PMDA content is preferably more than 65 mol% in order to have a linear thermal expansion coefficient of 30 ppm / DEG C or lower, and 90 mol %. In addition, the same effect can be obtained by applying the second dianhydride to BPDA, and the linear thermal expansion coefficient can be improved by additionally adding TFDB even if FFDA is applied. It can be seen from Examples 3 and 4 that the improvement effect is greater when the first-input dianhydride is PMDA than when it is 6FDA. In Examples 7 and 8, it was confirmed that the linear thermal expansion coefficient was further improved as the amount of TFDB added in the tertiary dianhydride was increased.

Claims (18)

(2, 4, 5-benzene tetracarboxylic dianhydride, PMDA), including diamines including 2,2 ' -trifluoromethyl benzidine (TFDB) Introducing a hydride; Bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA), and diamines including 2,2'-bis (trifluoromethyl) , And biphenyltetracarboxylic dianhydride (BPDA). 2. A process for producing a polyamic acid according to claim 1, wherein the dianhydride is at least one selected from the group consisting of biphenyltetracarboxylic dianhydride (BPDA) and biphenyltetracarboxylic dianhydride (BPDA). The process for producing a polyamic acid according to claim 1, wherein the molar ratio of the PMDA to one or more selected from 6FDA and BPDA is 90 to 25: 10 to 75. The method of claim 1, wherein the molar ratio of PMDA to 6FDA is 90 to 70: 10 to 30. The method of claim 1, wherein the molar ratio of PMDA to BPDA is from 90 to 25: 10 to 75. The method of claim 1, wherein the molar ratio of PMDA to 6FDA to BPDA is from 90 to 50: 5 to 30: 5 to 20. The method of claim 1, wherein the diamine is selected from the group consisting of 9,9-Bis (4-aminophenyl) fluorene (FDA), and 9,9- aminophenyl) fluorene, and FFDA. The method of producing a polyamic acid according to claim 1, The method of claim 6, wherein the 9,9-bis (4-aminophenyl) fluorene (FDA) and the 9,9-bis (3-fluoro-4-aminophenyl) fluorene, and FFDA) is added in an amount of 1 mol% to 20 mol% based on the total molar amount of the diamine. (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA) derived from recurring units derived from 2,2'-bis (trifluoromethyl) benzidine, TFDB Repeating units derived from a first block structure including a repeating unit and 2,2'-bis (trifluoromethyl) benzidine (TFDB) and a repeating unit derived from 2,2-bis (3,4-dicarboxyphenyl) Containing a repeating unit derived from at least one selected from the group consisting of hexafluoropropane dianhydride (6FDA) and biphenyltetracarboxylic dianhydride (BPDA) Polyamic acid comprising a block structure. The polyamic acid according to claim 8, wherein the molar ratio of at least one of 6FDA and BPDA in the first block structure to the PMDA in the second block structure is 90 to 25:10 to 75. The polyamic acid according to claim 8, wherein the molar ratio of PMDA in the first block structure to 6FDA in the second block structure is 90 to 70: 10 to 30. The polyamic acid according to claim 8, wherein the molar ratio of PMDA in the first block structure to BPDA in the second block structure is 90 to 25: 10 to 75. The method of claim 8, wherein the molar ratio of PMDA in the first block structure to BPDA in the second block structure in the second block structure is from 90 to 50: 5 to 30: 5 to 20 in the second block structure. Micky. 9. The method according to claim 8, wherein the block structure comprising a repeating unit derived from bis TFDB and a repeating unit derived from at least one selected from 6FDA and BPDA is selected from the group consisting of 9,9-Bis (4-aminophenyl ) further comprises a repeating unit derived from at least one member selected from the group consisting of fluorine, fluorine, FDA, and 9,9-bis (3-fluoro-4-aminophenyl) Polyamic acid. 14. The polyamic acid according to claim 13, wherein the content of at least one selected from the group consisting of FDA and FFDA is 1 mol% to 20 mol% based on the total molar amount of diamine. A polyimide resin produced from the polyamic acid according to claim 8. A polyimide film produced from the polyimide resin according to claim 15. The polyimide film according to claim 16, wherein the polyimide film has a coefficient of thermal expansion of 30 ppm / ° C or less at 50 to 350 ° C, a transmittance of 85% or more at 550 nm as measured by a UV spectrometer, Lt; / RTI &gt; or less. An image display device comprising the polyimide film according to claim 16.