KR102271028B1 - 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 producing a polyamic acid, a polyamic acid prepared therefrom, a polyimide resin, and a polyimide film, and the linear thermal expansion of the polyimide film prepared therefrom by changing to a divided input method when one type of diamine is added It relates to the development of polyimide compositions with improved modulus.

Description

Method of preparing polyamic acid, polyamic acid, polyimide resin and polyimide film prepared therefrom {Method of preparing Polyamic acid and Polyamic acid, Polyimide resin and Polyimide film thereby}

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

In general, a polyimide (PI) film is a film formed of a polyimide resin, and the polyimide resin is obtained by solution polymerization of an aromatic dianhydride and an aromatic diamine or an aromatic diisocyanate to prepare a polyamic acid derivative, followed by ring closure dehydration at high temperature. It refers to a high heat-resistant resin manufactured by imidization.

Because such polyimide films have excellent mechanical, heat resistance and electrical insulation properties, they are used in a wide range of electronic materials such as semiconductor insulating films, TFT-LCD electrode protective films, and flexible printed wiring circuit boards.

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

U.S. Patent Nos. 4595548, 4603061, 4645824, 4895972, 5218083, 5093453, 5218077, 5367046, 5338826. No. 5986036, No. 6232428 and Korean Patent Laid-Open No. 2003-0009437 disclose that -O-, -SO ₂ -, CH ₂ -, etc., is a monomer of a bent structure connected to the m-position, not the p-position, or -CF ₃ There is a report of manufacturing a polyimide having a novel structure with improved transmittance and color transparency to the extent that thermal properties are not significantly reduced by using an aromatic dianhydride dianhydride and an aromatic diamine monomer having a substituent such as -CF 3 In terms of mechanical properties, heat resistance, and birefringence, the results were insufficient for use as a material for display devices such as OLED, TFT-LCD, and flexible display.

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

A preferred embodiment of the present invention is a diamine containing bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and pyromellitic dianhydride (1,2,4,5-benzene tetracarboxylic) adding dianhydride, including dianhydride, PMDA); and diamines including bis trifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) And biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) provides a method for producing a polyamic acid comprising the step of adding a dianhydride comprising at least one selected from the group consisting of will do

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

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

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 is bisaminophenyl fluorene (9,9-Bis(4-aminophenyl)fluorene, FDA) and bisfluoroaminophenyl fluorene (9,9-Bis(3-fluoro-4-aminophenyl)fluorene, FFDA) It is characterized in that one or more selected from among are additionally added.

selected from the above bisaminophenyl fluorene (9,9-Bis(4-aminophenyl)fluorene, FDA) and bisfluoroaminophenyl fluorene (9,9-Bis(3-fluoro-4-aminophenyl)fluorene, FFDA) At least one type is characterized in that it is added in an amount of 1 mol% to 20 mol% based on the total moles of diamine.

Another preferred embodiment of the present invention is a repeating unit derived from bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and pyromellitic dianhydride (1,2,4,5- A block structure containing a repeating unit derived from benzene tetracarboxylic dianhydride, PMDA) and a repeating unit derived from bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and 2,2-bis(3) Derived from at least one selected from ,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) It is to provide a polyamic acid comprising a block structure including a repeating unit.

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

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

A 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 comprising a repeating unit derived from the bis TFDB and a repeating unit derived from at least one selected from 6FDA and BPDA is bisaminophenyl fluorene (9,9-Bis(4-aminophenyl)fluorene, FDA) and It is characterized in that it further comprises a repeating unit derived from at least one selected from bisfluoroaminophenyl fluorene (9,9-Bis(3-fluoro-4-aminophenyl)fluorene, FFDA).

The content of at least one selected from FDA and FFDA is characterized in that it is 1 mol% to 20 mol% based on the total moles of diamine.

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

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

The polyimide film has a coefficient of thermal expansion (Coefficient of Thermal Expansion) of 30ppm/°C or less at 50 to 350°C, a transmittance of 85% or more at 550 nm when the transmittance is measured with 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 yellowness and transmittance after forming a film or film, and a polyamic acid, polyimide resin and polyimide film prepared therefrom.

According to an embodiment of the present invention, diamine and pyromellitic dianhydride (1,2,4,5-benzene including bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB)) adding dianhydride containing tetracarboxylic dianhydride, PMDA); and diamines including bis trifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) And biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) provides a method for producing a polyamic acid comprising the step of adding a dianhydride comprising at least one selected from the group consisting of do.

The present invention can obtain the effect of improving the coefficient of linear thermal expansion while maintaining the optical properties at an excellent level by introducing one or more diamines at least once under specific conditions, for example, divided into primary and secondary.

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, diamine and pyromellitic dianhydride (1,2, 4,5-benzene tetracarboxylic dianhydride (PMDA) containing dianhydride; and diamines including bis trifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) It is preferable to carry out including the step of secondary input of a dianhydride containing at least one selected from the group consisting of .

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

When at least one selected from PMDA, 6FDA, and BPDA is out of the molar ratio range, there may be a problem of having a yellowness of 10 or more or a coefficient of thermal expansion of 30 ppm/°C or more.

In the present specification, diamine and pyromellitic dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA) including the bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) The step of adding the dianhydride containing is named as the first input, and diamine and 2,2-bis(3) containing bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) , 4-dicarboxyphenyl) containing at least one selected from hexafluoropropane dianhydride (6FDA) and biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) The step of inputting the dianhydride may be named as the secondary input, but this does not limit the order of the input, and is only named to distinguish the input step.

At this time, when two or more types are added from one or more selected from 6FDA and BPDA at the time of the second input, it means that the total moles of dianhydride at the time of the second input is added compared to PMDA at the time of the first input .

In addition, when 6FDA is selected and added from one or more selected from 6FDA and BPDA at the time of the second input, the molar ratio of PMDA at the first input to 6FDA at the second input is 90 to 70: 10 to 30, Preferably it is 90 to 75: 10 to 25 is good.

When the PMDA at the time of the first input and 6FDA at the time of the second input are out of the molar ratio range, if the ratio of PMDA is higher than the range, the linear thermal expansion coefficient is very low, but there may be a problem that the yellowness is very high, and the ratio of 6FDA If it is higher than this range, the yellowness is very low, but there may be a problem in that the linear thermal expansion coefficient increases.

In addition, when BPDA is selected from at least one selected from 6FDA and BPDA at the time of the second input, the molar ratio of PMDA at the time of the first input to BPDA at the time of the second input is 90 to 25: 10 to 75, Preferably 85 to 30: It is good that 15 to 70.

When PMDA at the time of the first input and BPDA at the time of the second input are out of the molar ratio range, if the ratio of PMDA becomes higher than the range, the linear thermal expansion coefficient is very low, but there may be a problem that the yellowness is very high, and the ratio of BPDA If it is higher than this range, there may be a problem in that the yellowness is lowered compared to PMDA, but the linear thermal expansion coefficient is increased.

In one embodiment of the present invention, when two or more kinds are input from one or more selected from 6FDA and BPDA at the time of the second input, PMDA at the first input vs. 6FDA at the time of the second input vs. BPDA at the second input The molar ratio of 90-50:5-30:5-20 is more preferable.

When PMDA at the time of the first input and 6FDA and BPDA at the time of the second input are out of the molar ratio range, there may be a problem of having a yellowness of 10 or more or a coefficient of thermal expansion of 30 ppm/°C or more.

In the present invention, after inputting the dianhydride containing PMDA first, the input of the dianhydride containing at least one selected from 6FDA and BPDA is more linear than when the dianhydride containing PMDA is added later. It is more preferable in that the thermal expansion coefficient and yellowness can be improved simultaneously.

That is, in one embodiment of the present invention, diamine and pyromellitic dianhydride (1,2,4,5-benzene including bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB)) Dianhydride containing tetracarboxylic dianhydride, PMDA) is added first, and diamine containing bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and 2,2-bis(3,4) -Dicarboxyphenyl) dianhydride comprising at least one selected from hexafluoropropane dianhydride (6FDA) and biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) It is preferable that the ride is added later in that the physical properties of the present invention can be further improved.

In addition, the diamine in the secondary input is bisaminophenyl fluorene (9,9-Bis(4-aminophenyl)fluorene, FDA) and bisfluoroaminophenyl fluorene (9,9-Bis(3-fluoro-4) -aminophenyl)fluorene, FFDA) may be additionally added. When one or more selected from the FDA and FFDA is additionally added, the effect of improving the glass transition temperature can be obtained.

At least one selected from the FDA and FFDA is preferably included in an amount of 1 mol% to 20 mol%, preferably 1 to 10 mol%, based on the total mole of diamine. When at least one selected from the FDA and FFDA is out of the above range, when the content is less than 1 mol%, the glass transition temperature improvement effect may be hardly improved, and when it exceeds 20 mol%, the yellowness and thermal expansion coefficient are lowered. there may be

According to one embodiment of the present invention, diamine and 2,2-bis (3,4-) containing bis trifluoromethyl benzidine (2,2'-bis (trifluoromethyl) benzidine, TFDB) as the secondary input Dianhydride comprising at least one selected from dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) The third inputting step can be carried out including.

The diamine and dianhydride at the time of the third input may be added by appropriately adjusting the molar ratio of the diamine and the dianhydride at the time of the first and second input as described above.

As diamines used in one embodiment of the present invention, in addition to TFDB, FDA and FFDA, oxydianiline (4,4'-Oxydianiline, ODA), p-phenylene diamine (pPDA), m-phenylenediamine (meta-phenylene diamine, mPDA), p-methylene dianiline (para-Methylene Dianiline, pMDA), m-methylene dianiline (meta-Methylene Dianiline, mMDA), bisaminophenoxy benzene (1,3-bis(3) -aminophenoxy) benzene, 133APB), bisaminophenoxybenzene (1,3-bis(4-aminophenoxy) benzene, 134APB), bisaminophenoxyphenyl hexafluoropropane (2,2'-bis[4(4- aminophenoxy)phenyl] hexafluoropropane, 4BDAF), bisaminophenyl hexafluoropropane (2,2'-bis(3-aminophenyl)hexafluoropropane, 33-6F), bisaminophenyl hexafluoropropane (2,2'-bis() 4-aminophenyl)hexafluoropropane, 44-6F), bis(4-aminophenyl)sulfone, 4DDS), bis(3-aminophenyl)sulfone (3DDS), cyclohexanediamine (1,3) -Cyclohexanediamine, 13CHD), cyclohexanediamine (1,4-Cyclohexanediamine, 14CHD), bisaminophenoxyphenylpropane (2,2-Bis[4-(4-aminophenoxy)-phenyl]propane, 6HMDA), bisaminohydr Roxyphenyl hexafluoropropane2,2-Bis(3-amino-4-hydroxy-phenyl)-hexafluoropropane, 6FAP), bisaminophenoxy diphenyl sulfone (4,4'-Bis(3-amino phenoxy) diphenyl sulfone , DBSDA) may contain one or more selected from and is not limited to the above-mentioned types.

On the other hand, the dianhydride used in the present invention is, in addition to PMDA, 6FDA, and BPDA, 4-(2,5-dioxotetrahydrofuran-3-yl)-1,2,3,4-tetrahydronaphthalene-1, 2-dicarboxylic anhydride (TDA), benzophenone tetracarboxylic dianhydride (3,3,4,4-Benzophenone tetracarboxylic dianhydride, BTDA), oxydiphthalic dianhydride (4,4-Oxydiphthalic dianhydride) ,ODPA), biscarboxyphenyl dimethyl silane dianhydride ( Bis(3,4dicarboxyphenyl)dimethyl-silane dianhydride, SiDA), bisdicarboxyphenoxy diphenyl sulfide dianhydride (4,4-bis(3,4-dicarboxyphenoxy) )diphenyl sulfide dianhydride, BDSDA), sulfonyldiphthalic anhydride (SO ₂ DPA), cyclobutane tetracarboxylic dianhydride (Cyclobutane -1,2,3,4 - tetracarboxylic dianhydride, CBDA), may include one or more selected from isopropylidene iphenoxy bis phthalic anhydride (4,4'-(4,4'-Isopropylidenediphenoxy)bis(phthalic anhydride), 6HBDA), and the above-mentioned types not limited to

In one embodiment of the present invention, it participates in the polymerization reaction including the above-described diamine and dianhydride components.

Although the conditions at the time of the said reaction are not specifically limited, 0-80 degreeC of reaction temperature is preferable, and 2-48 hours of reaction time are preferable. In addition, it is more preferable to use 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 dissolves the polyamic acid. Known reaction solvents include m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), acetone, ethyl acetate, diethyl Formamide (DEF), diethylacetamide (DEA), Propylene glycol monomethyl ether (PGME), Propylene glycol monomethyl ether Acetate (PGMEA), Ethyl, Lactate, 3-Methoxy-N,N-Dimethylpropionamide, 3-Butoxy-N , Use at least one polar solvent selected from N-methylpropionamide. In addition, a low-boiling-point solution such as tetrahydrofuran (THF), chloroform, or a low-absorption solvent such as γ-butyrolactone may be used. It is not limited to the above-mentioned types, and these solvents may be used alone or in two or more types depending on the purpose.

The content of the organic solvent is not particularly limited, but in order to obtain an appropriate molecular weight and viscosity of the polyamic acid solution, the content of the organic solvent is preferably 50 to 95% by weight of the total polyamic acid solution, more preferably 70 to 90% by weight It is more preferable that

According to another embodiment of the present invention, a repeating unit and pyromellitic dianhydride (1,2,4,5) derived from bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) -Bene tetracarboxylic dianhydride (PMDA) with a first block structure including a repeating unit and bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) with a repeating unit and 2,2- At least one selected from bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) To provide a polyamic acid comprising a second block structure comprising a repeating unit derived from.

The polyamic acid is preferably prepared by the above-described manufacturing method.

The polyamic acid prepared by the above manufacturing method is prepared by a method in which one type of diamine is divided and added at once like the existing method by including a first block structure and a second block structure containing one type of diamine in a specific content. Compared to polyamic acid, yellowness and transmittance are not lowered, and the effect of improving the linear thermal expansion coefficient can be obtained.

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

When at least one selected from PMDA in the first block structure and 6FDA and BPDA in the second block structure is out of the molar ratio range, there may be a problem having a yellowness of 10 or more or a coefficient of thermal expansion of 30 ppm/℃ or more. have.

In addition, 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.

When 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 is very low, but there may be a problem that the yellowness is very high, and 6FDA If the ratio of is higher than the range, the yellowness is very low, but there may be a problem in that the linear thermal expansion coefficient increases.

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

When PMDA in the first block structure and BPDA 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 is very low, but there may be a problem that the yellowness is very high, BPDA When the ratio of is higher than the range, there is an advantage of lowering the yellowness compared to PMDA, but there may be a problem in that the linear thermal expansion coefficient is 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, preferably 90 to 55:5-30: It is more preferable that it is 5-15.

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

In addition, the block structure comprising a repeating unit derived from the bis TFDB and a repeating unit derived from at least one selected from 6FDA and BPDA is bisaminophenyl fluorene (9,9-Bis(4-aminophenyl)fluorene, FDA ) and bisfluoroaminophenyl fluorene (9,9-Bis(3-fluoro-4-aminophenyl)fluorene, FFDA) may further include a repeating unit derived from at least one selected from the group consisting of. When one or more selected from the FDA and FFDA is further included, the effect of improving the glass transition temperature can be obtained.

At least one selected from the FDA and FFDA is preferably included in an amount of 1 to 20 mol%, preferably 1 to 10, based on the total mole of diamine. When at least one selected from the FDA and FFDA is out of the above range, when the content is less than 1 mol%, the glass transition temperature improvement effect may be hardly improved, and when it exceeds 20 mol%, the yellowness and thermal expansion coefficient are lowered. there may be

The method of imidating the above-mentioned polyamic acid to manufacture a polyimide resin is not specifically limited, A conventionally well-known method can be used. As a method for imidizing the polyamic acid, a thermal imidization method, a chemical imidization method, a thermal imidization method and a chemical imidization method may be used in combination, but it is more preferable to use a thermal imidization method. More preferably, the solution subjected to the chemical imidization method is precipitated, purified, dried, and then dissolved again in a solvent before use. This solvent is the same as the solvent mentioned above. Chemical imidization is a method of applying a dehydrating agent represented by an acid anhydride such as acetic anhydride and an imidization catalyst represented by tertiary amines such as isoquinoline, β-picoline, and pyridine to a polyamic acid solution. Thermal imidization may be used in combination with chemical imidization, and heating conditions may vary depending on the type of 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, then adding the imidized solution to a second solvent, precipitation, filtration, and drying to obtain a solid content of a polyimide resin, and prepare the obtained polyimide resin solid content 1 It can also be obtained through a film forming process using a polyimide solution dissolved in a solvent.

That is, after preparing a polyimide resin by chemical imidization of the above-described polyamic acid, precipitation, drying, dissolving in a solvent to form a solution, and applying to the support, the applied solution is filmed on the support by dry air and heat treatment.

The first solvent may be the same solvent as the solvent used for polymerization of the polyamic acid solution, and the second solvent is used with a lower polarity than the first solvent in order to obtain a solid content of the polyamic acid resin, specifically water, It may be at least one selected from alcohols, ethers and ketones. In this case, the content of the second solvent is not particularly limited, but is preferably 5 to 20 times by weight relative to the weight of the polyamic acid solution.

The film forming temperature condition of the coated film is preferably 250 ~ 500 ℃, and as a support, a glass plate, aluminum foil, a circulating stainless belt, a stainless drum, etc. can be used.

The processing time required for film formation depends on the temperature, the type of 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, it is good to carry out in the range between 5 minutes and 30 minutes.

The heat treatment temperature is between 100 and 500°C, and the treatment time is between 1 and 30 minutes. After completion of drying and imidization by heat treatment, it is peeled off from the support.

Although the thickness of the polyimide film obtained is not specifically limited, It is preferable that it is the range of 10-250 micrometers, It is good that it is 10-100 micrometers more preferably.

The polyimide film prepared in the present invention preferably has a coefficient of thermal expansion (Coefficient of Thermal Expansion) of 30 ppm/°C or less at 50 to 350°C.

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

In addition, the polyimide film preferably has a yellowness of 10 or less, preferably 5 or less, based on a film thickness of 10 to 100 μm.

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

<Example 1>

After filling 273.882 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, TFDB 28.821 was dissolved, PMDA 19.631 g was added and stirred for 3 hours. Thereafter, 3.202 g of TFDB was further dissolved, and 4.443 g of 6FDA was added thereto, followed by reaction for 15 hours. As a result, a polyamic acid solution having a solid content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Example 2>

After filling 284.922 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, 25.618 g of TFDB was dissolved, and PMDA After adding 17.450 g, the mixture was stirred for 3 hours. After that, 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 content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Example 3>

After filling 295.963 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, 22.416 g of TFDB was dissolved, and then PMDA After adding 15.268 g, the mixture was stirred for 3 hours. After that, after dissolving 9.607 g of TFDB in addition, 13.328 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Example 4>

After filling 295.963 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, 9.607 g of TFDB was dissolved, and then 6FDA After adding 13.328 g, 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 content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Example 5>

After filling 281.419 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen into a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, 16.012 g of TFDB was dissolved, and then PMDA After adding 10.906 g, the mixture was stirred for 3 hours. After that, 16.012 g of TFDB was further dissolved, and 14.711 g of BPDA was added thereto and reacted for 15 hours. As a result, a polyamic acid solution having a solid content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 10 minutes after reaching 350° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Example 6>

As a reactor, 283.076 g of N,N-dimethylacetamide (DMAc) was filled while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller, and cooler. After dissolving 13.450 g of TFDB, 9.161 g of PMDA was added and stirred for 3 hours. Thereafter, 23.825 g of TFDB and 1.384 g of FFDA were further dissolved, and 22.949 g of BPDA was added thereto, followed by reaction for 15 hours. As a result, a polyamic acid solution having a solid content of 20% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 10 minutes after reaching 350° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Example 7>

As a reactor, N-methyl-2-pyrrolidone (NMP) 288.638 was filled in a 500ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler while passing nitrogen. After dissolving 22.416 g of TFDB, PMDA 15.268 g was added and stirred for 3 hours. After that, after dissolving 9.607 g of TFDB in addition, 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 content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Example 8>

As a reactor, N-methyl-2-pyrrolidone (NMP) 288.638 was filled in a 500ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler while passing nitrogen. After dissolving 22.416 g of TFDB, PMDA 15.268 g was added and 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 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 content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Comparative Example 1>

After filling 268.362 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, 32.023 g of TFDB was dissolved, and PMDA After adding 20.721 g, the mixture was stirred for 3 hours. After that, 2.221 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Comparative Example 2>

After filling 295.963 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, 32.023 g of TFDB was dissolved, and PMDA After adding 15.268 g, the mixture was stirred for 3 hours. After that, 13.328 g of 6FDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Comparative Example 3>

After filling 295.963 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, 32.023 g of TFDB was dissolved, and then 6FDA After adding 13.328 g, the mixture was stirred for 3 hours. After that, 15.268 g of PMDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

<Comparative Example 4>

After filling 301.483 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, nitrogen injection device, dropping funnel, temperature controller and cooler as a reactor, 32.023 g of TFDB was dissolved, and PMDA After adding 14.178 g, 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 content of 17 wt% was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air at 80° C. for 20 minutes, and then cured by isothermal treatment for 30 minutes after reaching 370° C. Then, it cooled gradually, isolate|separated from the glass plate, and obtained the polyimide film.

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

(1) Measurement of transmittance (TT)

The transmittance was measured three times at 550 nm using a UV spectrometer (Cotica Minolta CM-3700d), and the average value is shown in Table 1.

(2) Measurement of yellowness (Y.I.)

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

(3) Measurement of coefficient of thermal expansion (CTE)

Using TMA (TA Instrument, Q400), the coefficient of linear thermal expansion at 50 to 350° C. was measured twice according to the TMA-Method. The size of the specimen was 4 mm×24 mm, the load was 0.02 N, and the temperature increase rate was 10° C./min. Since residual stress may remain in the film through heat treatment after forming the film, the residual stress is completely removed by the first run, and the second value is presented as an actual measurement value.

number Raw material ratio and dosing sequence 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 TFDB(70)-PMDA(70)
-TFDB(30)-6FDA(30) 10 6.76 88.79 23.28 4 TFDB(30)-6FDA(30)
TFDB(70)-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 TFDB(70)-PMDA(70)
-TFDB(30)-6FDA(20)-BPDA(10) 10 7.08 88.37 14.29 8 TFDB(70)-PMDA(70)
-TFDB(20)-6FDA(20)
-TFDB(10)-BPDA(10) 10 7.11 88.36 11.29 ratio
school
Yes One TFDB(100)
-PMDA(95)-6FDA(5) 11 10.90 87.63 -11.16 2 TFDB(100)
-PMDA(70)-6FDA(30) 10 6.96 88.87 31.51 3 TFDB(100)
-6FDA(30)-PMDA(70) 10 7.32 89.20 30.31 4 TFDB(100)
-PMDA(65)-6FDA(35) 10 6.34 89.55 46.74

As shown in Table 1, when comparing Examples and Comparative Examples respectively, in the case of Examples 1 to 8, in which the TFDB is divided, all of the yellowness, transmittance, and coefficient of linear thermal expansion are satisfied at excellent levels, but Comparative Example 1 has transmittance was significantly lowered, and Comparative Examples 2 to 4 showed physical properties in which the linear thermal expansion coefficient was significantly lowered.

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

In addition, when the primary dianhydride is PMDA and the secondary dianhydride is 6FDA, the PMDA content is preferably over 65 mol% to have a linear thermal expansion coefficient of 30 ppm/℃ or less, and 90 mol to prevent yellowness deterioration It is preferable not to exceed %. In addition, the same effect can be seen even when the secondary dianhydride is applied as BPDA, and even when FFDA is additionally applied, the linear thermal expansion coefficient can be improved by dividingly inputting TFDB. Looking at Examples 3 and 4, it can be seen that the improvement effect is greater when the primary input dianhydride is PMDA than when 6FDA is used. And, looking at Examples 7 and 8, it was confirmed that the linear thermal expansion coefficient was further improved as the divided input of TFDB increased when the tertiary dianhydride was applied.

Claims (18)

Diamine containing bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and dianhydride containing pyromellitic dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA) inputting hydride (a first block structure formation step); and diamines including bis trifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) And biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) the step of adding a dianhydride containing at least one selected from (second block structure formation step); including,
A method of producing a polyamic acid in which the second block structure forming step is performed after the first block structure forming step. The method according to claim 1, wherein the molar ratio of PMDA to at least one 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 according to claim 1, wherein the molar ratio of PMDA to BPDA is 90 to 25: 10 to 75. The method according to claim 1, wherein the molar ratio of PMDA to 6FDA to BPDA is 90 to 50: 5 to 30: 5 to 20. According to claim 1, wherein the diamine is bis amino phenyl fluorene (9,9-Bis (4-aminophenyl) fluorene, FDA) and bis fluoro amino phenyl fluorene ( 9,9-Bis (3-fluoro-4-) aminophenyl) fluorene, FFDA), a method for producing a polyamic acid, characterized in that the addition of at least one selected from the group consisting of. 7. The method of claim 6, wherein the bis amino phenyl fluorene (9,9-Bis (4-aminophenyl) fluorene, FDA) and bis fluoro amino phenyl fluorene ( 9,9-Bis (3-fluoro-4-aminophenyl) fluorene, FFDA) is added in an amount of 1 mol% to 20 mol% based on the total mole of diamine. A repeating unit derived from bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and a pyromellitic dianhydride (1,2,4,5-benzene tetracarboxylic dianhydride, PMDA) derived from A first block structure including a repeating unit and a repeating unit derived from bistrifluoromethyl benzidine (2,2'-bis(trifluoromethyl)benzidine, TFDB) and 2,2-bis(3,4-dicarboxyphenyl) A second comprising a repeating unit derived from at least one selected from hexafluoropropane dianhydride (6FDA) and biphenyl tetracarboxylic dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA) By including a block structure,
A polyamic acid prepared by the method of claim 1 . The polyamic acid according to claim 8, wherein the molar ratio of PMDA in the first block structure to at least one selected from 6FDA and BPDA in the second block structure is 90 to 25: 10 to 75. The polyamic acid according to claim 8, wherein a 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 a molar ratio of PMDA in the first block structure to BPDA in the second block structure is 90 to 25: 10 to 75. The polya according to claim 8, wherein a molar ratio of PMDA in the first block structure to 6FDA in the second block structure to BPDA in the second block structure is 90-50:5-30:5-20. Mixan. The block structure according to claim 8, wherein the block structure including the repeating unit derived from the bis TFDB and the repeating unit derived from one or more selected from 6FDA and BPDA is bisaminophenyl fluorene (9,9-Bis(4-aminophenyl ) fluorene, FDA) and bis fluoro amino phenyl fluorene (9,9-Bis (3-fluoro-4-aminophenyl) fluorene, FFDA) characterized in that it further comprises a repeating unit derived from at least one selected from polyamic acid. The polyamic acid according to claim 13, wherein the content of at least one selected from FDA and FFDA is 1 mol% to 20 mol% based on the total moles of diamine. A polyimide resin prepared from the polyamic acid according to claim 8. A polyimide film made from the polyimide resin according to claim 15 . The method according to claim 16, wherein the polyimide film has a coefficient of thermal expansion (Coefficient of Thermal Expansion) of 30 ppm/°C or less at 50 to 350°C, transmittance of 85% or more at 550 nm when measured with a UV spectrometer, and a yellowness of 10 A polyimide film characterized by the following. An image display device comprising the polyimide film according to claim 16 .