WO2023038322A1 - Polyamic acid composition and polyimide prepared therefrom - Google Patents

Abstract

The present invention relates to a polyamic acid composition and a polyimide including same and exhibits excellent thermal properties such as dimensional stability and heat resistance while retaining high transparency.

Description

Polyamic acid composition and polyimide prepared therefrom

The present invention relates to a polyamic acid composition and a polyimide prepared therefrom.

In general, polyimide (PI) resin refers to a highly heat-resistant resin prepared by solution polymerization of aromatic dianhydride and aromatic diamine or aromatic diisocyanate to prepare a polyamic acid derivative, followed by imidization by curing. refers to

Polyimide is a polymer material with thermal stability based on a rigid aromatic main chain, and has mechanical properties such as excellent strength, chemical resistance, weather resistance and heat resistance based on the chemical stability of the imide ring. In addition, polyimide is in the limelight as a high-functional polymer material applicable to a wide range of industries such as electronics, communication, and optics due to its excellent electrical properties such as insulating properties and low permittivity.

In recent years, as various electronic devices have become thinner, lighter and smaller, many studies have been conducted to use thin polyimide films, which are lightweight and have excellent flexibility, as insulating materials for circuit boards or as display substrates that can replace glass substrates for displays. .

However, in order to utilize the polyimide film in the field of electronic materials as described above, high transparency in the visible light region is required, and since heat may be applied in the process of forming an element on a substrate, high heat resistance and dimensional stability are required. .

As a method for improving the transparency of polyimide, there has been a method of reducing the electron density by introducing a relatively electronegative substituent including halogen, sulfur, or oxygen into the repeating chain, but thermal properties such as dimensional stability and heat resistance have been There was a problem with a significant drop.

Therefore, it is required to develop a polyimide having excellent thermal properties such as dimensional stability and heat resistance while having high transparency.

An object of the present invention is to provide a polyamic acid composition and a polyimide film having excellent thermal properties such as dimensional stability and heat resistance while having high transparency.

In particular, the present invention can provide a polyamic acid composition and polyimide having excellent processability, excellent mechanical properties, as well as low weight loss and low expansion coefficient against heat due to a high glass transition temperature while having high transparency.

Polyimide (PI) resin is prepared by polymerization of aromatic dianhydride and aromatic diamine or aromatic diisocyanate to prepare a polyamic acid derivative, followed by imidization by curing.

Polyimide has excellent thermal stability based on a rigid aromatic backbone. However, as a counterweight to the high thermal stability due to the aromatic main chain, the transparency is so low that there is a limit to use in the electronic material field, especially in the display field requiring high transparency.

The present invention includes a compound having a special type of aromaticity in addition to a compound having 1 to 2 aromatic rings as a part of the dianhydride monomer component and / or diamine component constituting the polyimide, and by optimizing their content, A polyamic acid composition and polyimide having high transparency and excellent thermal properties can be provided.

In addition, the present invention has an effect of excellent processability by using a solvent having excellent compatibility with the polyimide precursor, being environmentally friendly, and having excellent dispersibility.

In particular, in addition to the coefficient of thermal expansion (CTE) and thermal decomposition temperature (Td), which are mainly used as criteria for determining the thermal properties of polyimide, the present invention is based on the glass transition temperature (Tg), which can predict thermal properties and also reflect mechanical properties. noticed.

The present invention maintains the glass transition temperature at a high level by taking advantage of the fact that the glass transition temperature is affected by the rigidity and crosslinking density of the aromatic main chain constituting the polyimide, thereby maintaining high transparency of the polyamic acid without significant reduction in thermal and mechanical properties. compositions and polyimides can be provided.

In the present invention, the polyimide precursor may mean dianhydride and diamine excluding the solvent in the polyamic acid composition.

The present invention relates to a polyamic acid composition. The polyamic acid composition includes a polyamic acid having a polymerization unit derived from a dianhydride monomer component and a diamine monomer component, and a solvent.

At this time, at least one of the dianhydride monomer component and the diamine monomer component may include a compound having a fluorene skeleton.

The fluorene skeleton may not generate a resonance effect due to electron transfer with the main chain of the dianhydride monomer component and/or the diamine monomer component.

Specifically, the dianhydride monomer component may include a compound having a fluorene skeleton, and the compound having a fluorene skeleton among the dianhydride monomer components is 9,9-bis(3,4-dicarboxyphenyl) Can be fluorene dianhydride (BPAF) or 4,4'-(9H-fluorene-9,9 diyl)bis(4,1-phenylene))bis(4-aminobenzamide) (FDA-ADA) there is.

In addition, the diamine monomer component may include a compound having a fluorene skeleton, and among the diamine monomer components, the compound having a fluorene skeleton is 9,9'-bis(4-aminophenyl)fluorene (BAFL) or 9, 9-bis(4-amino-3fluorophenyl)fluorene (FFDA).

The present invention can have high transparency by including a compound having a fluorene skeleton as at least one of the dianhydride monomer component and the diamine monomer component. This may have high transparency as the retardation in the thickness direction is reduced by the introduction of a compound having a fluorene skeleton. In addition, the fluorene skeleton does not generate a resonance effect due to the transfer (or excitation) of electrons with the main chain of the dianhydride monomer component and/or the diamine monomer component, and thus, the overall resonance effect of the polyimide precursor is lowered. It may be that the transparency increases.

The amount of the compound having a fluorene skeleton may be less than 30 mol% with respect to the polyimide precursor. Preferably, the amount of the compound having a fluorene skeleton may be less than 25 mol% based on the total amount of the dianhydride monomer component and the diamine monomer component. For example, the upper limit of the content of the compound having a fluorene skeleton is less than 24 mol%, less than 23 mol%, less than 22 mol%, less than 21 mol%, less than 20 mol% with respect to the total dianhydride monomer component and diamine monomer component Less than 19 mol%, less than 18 mol%, less than 17 mol%, less than 16 mol%, less than 15 mol%, less than 14 mol%, less than 13 mol%, less than 12 mol%, less than 11 mol%, 10 mol% less than 9 mol%, less than 8 mol% or less than 7 mol%, with lower limits greater than 0.01 mol%, greater than 0.05 mol%, greater than 0.9 mol%, greater than 1 mol%, greater than 2 mol%, greater than 3 mol% or greater than 4 mol%. Specifically, the compound having a fluorene skeleton is 0.5 mol% to 30 mol%, 0.6 mol% to 25 mol%, 0.7 mol% to 23 mol%, 3 mol% to 10 mol%, 3 mol% to 10 mol%, based on the total polyimide precursor. mol % to 9 mol % or 3 mol % to 7 mol %.

The content of the compound having a fluorene skeleton in the dianhydride monomer component may be less than 15 mol%, for example, the upper limit of the content of the compound having a fluorene skeleton in the dianhydride monomer component is less than 14 mol%, less than 13 mol%, less than 12 mol%, less than 11 mol%, less than 10 mol%, less than 9 mol%, less than 8 mol%, less than 7 mol% or less than 6 mol%, with lower limits greater than 0.01 mol% and 0.05 mol%. greater than mol %, greater than 0.9 mol %, greater than 1 mol %, greater than 2 mol %, greater than 3 mol % or greater than 4 mol %. Specifically, the compound having a fluorene skeleton among the dianhydride monomer components is 1 mol% to 10 mol%, 3 mol% to 10 mol%, 3 mol% to 9 mol%, or 3 mol% to 3 mol% with respect to the polyimide precursor 7 mol%.

The content of the compound having a fluorene skeleton in the diamine monomer component may be less than 15 mol%, for example, the upper limit of the content of the compound having a fluorene skeleton in the diamine monomer component is less than 14 mol%, less than 13 mol% , less than 12 mol%, less than 11 mol%, less than 10 mol%, less than 9 mol%, less than 8 mol%, less than 7 mol% or less than 6 mol%, with lower limits greater than 0.01 mol%, greater than 0.05 mol%, It may be greater than 1 mol%, greater than 2 mol%, greater than 3 mol% or greater than 4 mol%. Specifically, the compound having a fluorene skeleton among the diamine monomer components is 1 mol% to 10 mol%, 3 mol% to 10 mol%, 3 mol% to 9 mol%, or 3 mol% to 7 mol% based on the polyimide precursor may be %.

A compound having a fluorene skeleton can contribute to high transparency of polyimide after curing, but weakens mechanical strength and thermal properties. Specifically, when the content of the compound having a fluorene skeleton in the polyamic acid composition increases, the mechanical strength and thermal expansion coefficient of the cured polyamide decrease, and the thermal decomposition temperature decreases, resulting in deterioration in mechanical and thermal properties. Therefore, in the present invention, by limiting the content of the compound having a fluorene skeleton to the above range, it is possible to prevent deterioration of mechanical strength and thermal properties while having high transparency. In particular, when the content of the compound having a fluorene skeleton is within the above range, the rigidity and crosslinking density of the aromatic main chain, which can prevent a rapid decrease in glass transition temperature, can be maintained, so that after curing, mechanical strength and thermal properties are lowered can be minimized.

Specifically, the glass transition temperature after curing of the polyamic acid composition according to the present invention is 430 °C or higher. For example, the glass transition temperature of the polyamic acid composition according to the present invention after curing may be 435 ° C or higher, 440 ° C or higher, 445 ° C or higher, 450 ° C or higher, 455 ° C or higher, 460 ° C or higher, 465 ° C or higher or 470 ° C or higher. And, the upper limit is not particularly limited, but may be 600 ℃ or less or 500 ℃ or less.

In the present invention, by having the glass transition temperature as described above, it is possible to minimize deterioration in mechanical strength and thermal properties after curing of the polyamic acid composition, minimize flowability due to thermal deformation, and thus improve processability.

The dianhydride monomer component and the diamine monomer component other than the compound having a fluorene skeleton may each include a compound having one or two or more benzene rings. Specifically, the dianhydride monomer component and the diamine monomer component other than the compound having a fluorene skeleton may each include a compound having one or two benzene rings.

Among the dianhydride monomer components, compounds having one or two benzene rings are pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s- BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) , It may be at least one selected from the group consisting of oxydiphthalic dianhydride (ODPA) and 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA).

Specifically, the dianhydride monomer component other than the compound having a fluorene skeleton may include a compound having two benzene rings, and the compound having two benzene rings as the dianhydride monomer component is 3,3' ,4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 3,3' ,4,4'-benzophenonetetracarboxylic dianhydride (BTDA), oxydiphthalic dianhydride (ODPA) and 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA) It may be at least one selected from the group consisting of.

By including a compound having two benzene rings as a dianhydride monomer component other than a compound having a fluorene skeleton, transparency after curing of the polyamic acid composition can be improved, and excellent compatibility with the compound having the fluorene skeleton As a result, solvent dispersibility can be improved. In addition, by including two benzene rings, it is possible to prevent a rapid decrease in glass transition temperature.

In this case, the dianhydride monomer component having one or two benzene rings may be included in an amount of 80 mol% or more of the dianhydride monomer component. For example, the lower limit of the ratio of the dianhydride monomer component having one or two benzene rings among the dianhydride monomer components may be 82 mol% or more, 84 mol% or more, 86 mol% or more, or 88 mol% or more, The upper limit may be 99.9 mol% or less, 99.5 mol% or less, 99 mol% or less, or 98 mol% or less.

Compounds having one or two benzene rings among the diamine monomer components are 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6 -Diaminotoluene, 4,4'-diaminodiphenyl ether (ODA), 4,4-diaminobenzanilide (4,4-DABA), 2,2-dimethylbenzidine (M-TOLIDINE), 3, It may be at least one selected from the group consisting of 3-dimethylbenzidine (O-TOLIDINE) and 2,2'-bistrifluoromethylbenzidine (TFMB).

Specifically, the diamine monomer component other than the compound having a fluorene skeleton may be a compound having one benzene ring, and the compound having one benzene ring as the diamine monomer component is 1,4-diaminobenzene (PPD) , It may be at least one selected from the group consisting of 1,3-diaminobenzene (MPD), 2,4-diaminotoluene and 2,6-diaminotoluene.

By including a compound having one benzene ring as a diamine monomer component other than a compound having a fluorene skeleton, transparency after curing of the polyamic acid composition can be improved, and excellent compatibility with the compound having a fluorene skeleton makes it possible to use a solvent Dispersibility can be improved. In addition, by including one benzene ring, a rapid decrease in glass transition temperature can be prevented.

In this case, the diamine monomer component having one or two benzene rings may be included in an amount of 80 mol% or more of the diamine monomer component. For example, the lower limit of the ratio of the diamine monomer component having one or two benzene rings among the diamine monomer components may be 82 mol% or more, 84 mol% or more, 86 mol% or more, or 88 mol% or more, and the upper limit is 99.9 mol%. % or less, 99.5 mol% or less, 99 mol% or less, or 98 mol% or less.

The polyamic acid composition according to the present invention includes a solvent, and the solvent may be an organic solvent. Solvents compatible with the polyimide precursor include N,N-diethylacetamide (DEAC), N,N-dimethylpropionamide (DMPA), 3-methoxy-N,N-dimethylpropanamide (KJCMPA) Alternatively, N-methyl-2-pyrrolidone (NMP) may be selected from at least one selected from combinations thereof.

In addition, the solvent of the polyamic acid composition according to the present invention may have a boiling point of 150°C or higher. For example, the solvent of the polyamic acid composition may have a boiling point of 160°C or higher or 170°C or higher. Specifically, the lower limit of the boiling point of the solvent may be, for example, 155 ° C, 160 ° C, 165 ° C, 170 ° C, 175 ° C, 180 ° C, 185 ° C, 190 ° C, 195 ° C, 200 ° C or 201 ° C or higher, The upper limit may be, for example, 500°C, 450°C, 300°C, 280°C, 270°C, 250°C, 240°C, 230°C, 220°C, 210°C or 205°C or less. By having the boiling point as described above, separation of water and solvent may be facilitated during curing.

Since the polyimide precursor according to the present invention includes a compound having a fluorene skeleton, N,N-diethylacetamide (DEAC) or N,N-dimethylpropionamide (DMPA), an amide-based organic solvent that is particularly compatible therewith, ) can be used. By using the solvent as described above, it is possible to minimize cloudiness and improve the dispersibility of the polyimide precursor.

The polyamic acid composition according to the present invention may have a solid content in the range of 5 to 30% by weight. The solid content may be 7% by weight or more, 9% by weight or more, 10% by weight or more, 12% by weight or more, 14% by weight or more, or 15% by weight or more, and the upper limit is, for example, 30% by weight or less, 25% by weight or less % or less, 20% or less, 18% or less, 17% or less or 15% or less. The present application can implement the desired physical properties and viscosity within the above range.

As a method of polymerizing the dianhydride monomer component and the diamine monomer component, a conventional polyimide precursor polymerization method such as solution polymerization may be used.

For example, (1) a method in which the entire amount of the diamine monomer is placed in a solvent, and then a dianhydride monomer is added so as to be substantially equimolar to the diamine monomer to polymerize;

(2) a method in which the entire amount of the dianhydride monomer is placed in a solvent, and then a diamine monomer is added so as to be substantially equimolar to the dianhydride monomer to polymerize;

(3) After putting some components of the diamine monomers in a solvent, mixing some of the components of the dianhydride monomers with respect to the reaction components, adding the remaining diamine monomer components and subsequently adding the remaining dianhydride monomer components, a method of polymerizing the diamine monomer and the dianhydride monomer so that they are substantially equimolar;

(4) After putting the dianhydride monomer in a solvent, mixing some components of the diamine compound with respect to the reaction components, adding other dianhydride monomer components, and then adding the remaining diamine monomer components, followed by diamine monomer and dianane. and a method of polymerizing the hydride monomers so that they are substantially equimolar.

The polyamic acid composition according to the present invention may have a coefficient of thermal expansion (CTE) of 20 ppm/°C or less after curing. For example, the upper limit of the CTE may be 20 ppm/°C, 18 ppm/°C, 16 ppm/°C, 14 ppm/°C, 12 ppm/°C, 10 ppm/°C or 8 ppm/°C or less, and the lower limit may be, for example, For example, it may be at least 0.1 ppm/°C, 1 ppm/°C, 2.0 ppm/°C, 2.6 ppm/°C, 2.8 ppm/°C, 3.5 ppm/°C or 4 ppm/°C. In one example, the thermal expansion coefficient may be measured at 100 to 400 °C. The CTE can use TA's thermomechanical analyzer Q400 model, and after manufacturing polyimide into a film, cutting it into a width of 2 mm and a length of 10 mm, applying a tension of 0.05 N in a nitrogen atmosphere, 10 ° C / After raising the temperature from room temperature to 500 ° C at a rate of min, the slope of the 100 ° C to 400 ° C section can be measured while cooling again at a rate of 10 ° C / min.

In one example, the polyamic acid composition according to the present application may have a glass transition temperature of 430° C. or more after curing, and for example, the lower limit of the glass transition temperature is 440° C. or more, 445° C. or more, 450° C. or more, or 455° C. °C or higher or 460 °C or higher. The upper limit may be 600° C. or less. The glass transition temperature may be measured at 10 °C/min using TMA for polyimide prepared by curing the polyamic acid composition.

The polyamic acid composition according to the present application may have a thermal decomposition temperature of 1% by weight after curing of 540 ° C or higher. The thermal decomposition temperature can be measured using TA's thermogravimetric analysis Q50 model. In a specific embodiment, the polyimide obtained by curing the polyamic acid is heated to 150° C. at a rate of 10° C./min under a nitrogen atmosphere and maintained at an isothermal temperature for 30 minutes to remove moisture. Thereafter, the temperature may be raised to 600° C. at a rate of 10° C./min to measure the temperature at which a weight loss of 1% occurs. The lower limit of the thermal decomposition temperature may be, for example, 550 °C or higher, 555 °C or higher, 560 °C or higher, or 565 °C or higher. The upper limit may be, for example, 800°C, 750°C, 700°C, 650°C or 630°C or less.

In addition, the polyamic acid composition according to the present application may have light transmittance of 60% or more in a visible light region of 470 nm after curing. The light transmittance can be measured using a UV/Vis spectrophotometer. For example, the light transmittance is 61% or more, 62% or more, 63% or more, 64% or more, 65% or more, 66% or more, 67% or more, 68% or more, 69% or more, 70% or more, 71% It may be 72% or more, 73% or more, 74% or more, 75% or more, 76% or more, 77% or more, or 80% or more, and the upper limit is not particularly limited, but may be 90% or less or 85% or less.

In addition, the polyamic acid composition may have an elongation of 15% or more after curing, for example, 17% or more, 19% or more, 21% or more, 23% or more, or 25% or more. The upper limit is not particularly limited, but may be 40% or less. The elongation can be measured by the ASTM D-882 method using Instron 5564 UTM equipment after curing the polyamic acid composition into a polyimide film, cutting it into a width of 10 mm and a length of 40 mm.

In addition, the polyamic acid composition of the present application may have an elastic modulus of 6.9 GPa or more after curing. The lower limit of the elastic modulus may be, for example, 7.0 GPa or more, 7.1 GPa or more, 7.2 GPa or more, or 7.3 GPa or more. The upper limit is not particularly limited, but may be 15 GPa or less.

In addition, the polyamic acid composition may have a tensile strength of 230 MPa or more after curing. The lower limit of the tensile strength may be, for example, 240 MPa or more, 250 MPa or more, 260 MPa or more, 270 MPa or more, 280 MPa or more, 290 MPa or more or 300 MPa or more, and the upper limit may be, for example, 550 MPa or less or It may be 530 MPa or less. The elastic modulus and tensile strength were measured by the ASTM D-882 method using Instron 5564 UTM equipment after curing the polyamic acid composition to prepare a polyimide film, cutting it into a width of 10 mm and a length of 40 mm, and Tensile strength can be measured. The cross head speed at this time can be measured under the condition of 50 mm/min.

In addition, the present invention provides a method for producing a polyimide, comprising forming a polyamic acid composition prepared according to the method for producing a polyamic acid composition on a support and drying to prepare a gel, and curing the gel.

Specifically, the method for producing a polyimide of the present invention may include forming a film of the polyamic acid composition on a support, drying the film to prepare a gel, and curing the gel.

In the curing of the gel, the polyamic acid composition formed on the support is dried at a temperature of 20 to 120 ° C for 5 to 60 minutes to prepare a gel film, and the gel film is heated from 1 to 8 ° C to 30 to 500 ° C. /min, heat treatment at 450 to 500 ° C for 5 to 60 minutes, and cooling to 20 to 120 ° C at a rate of 1 to 8 ° C / min.

Curing the gel film may be performed at 30 to 500 °C. For example, the step of curing the gel film is 30 to 400 ° C, 30 to 300 ° C, 30 to 200 ° C, 30 to 100 ° C, 100 to 500 ° C, 100 to 300 ° C, 200 to 500 ° C, or 400 to 500 ° C. may be performed at °C.

The polyimide film may have a thickness of 5 to 20 μm. For example, the polyimide film may have a thickness of 5 to 18 μm, 6 to 16 μm, 7 to 14 μm, 8 to 12 μm, or 9 to 11 μm.

The support may be, for example, an inorganic substrate, and the inorganic substrate may include a glass substrate or a metal substrate, but it is preferable to use a glass substrate, and the glass substrate may be soda lime glass, borosilicate glass, or alkali-free glass. and the like may be used, but are not limited thereto.

Since the polyimide according to the present invention has excellent transparency and excellent thermal properties, it can be usefully used as a substrate such as a substrate for a device or a cover substrate for a display, and a film such as an optical film, an adhesive film, a tape or a protective film for a disk. can be usefully used. Specifically, the polyamic acid composition according to the present invention or the polyimide prepared using the same may be used as a transparent polyimide substrate for oxide TFT or a transparent polyimide substrate for LTPS.

Accordingly, the present invention can provide a transparent polyimide substrate for an oxide TFT manufactured using the polyamic acid composition or polyimide described above.

In addition, the present invention may provide a transparent polyimide substrate for LTPS manufactured using the polyamic acid composition or polyimide described above.

The polyamic acid composition according to the present invention and the polyimide including the same have excellent thermal properties such as dimensional stability and heat resistance while having high transparency. In particular, since the polyamic acid composition and the polyimide including the polyamic acid composition according to the present invention have high transparency and a high glass transition temperature, they have excellent mechanical properties and processability as well as low weight loss and low expansion coefficient with respect to heat.

Hereinafter, the present invention will be described in more detail through examples according to the present invention and comparative examples not according to the present invention, but the scope of the present invention is not limited by the examples presented below.

<Preparation of polyamic acid composition>

Example 1

N,N-dimethylpropionamide (DMPA) was introduced as a solvent while nitrogen was injected into a 500 ml reactor equipped with a stirrer and a nitrogen injection discharge pipe.

After setting the temperature of the reactor to 25 ° C., 90 parts by weight of biphenyltetracarboxylic dianhydride (BPDA) was added as a dianhydride monomer, and para-phenylene diamine (PPD) as a diamine monomer was completely dissolved. Thereafter, 10 parts by weight of 9,9-bis (3,4-dicarboxyphenyl) fluorene dianhydride (9,9-Bis (3,4-dicarboxyphenyl) fluorene Dianhydride, BPAF) was divided into 3 times at 30 minute intervals. Then, stirring was continued for 120 minutes to prepare a polymerized polyamic acid composition.

Examples 2 to 13

A polyamic acid solution was prepared in the same manner as in Example 1, except that the monomer components and content ratios were adjusted as shown in Table 1.

Comparative Examples 1 to 6

A polyamic acid solution was prepared in the same manner as in Example 1, except that the monomers and content ratios were adjusted as shown in Table 1.

division dianhydride
Diamine
Solid content (%) BPDA
(mole%) BPAF
(mole%) FDA-ADA
(mole%) PPD
(mole%) BAFL
(mole%) TFMB
(mole%) Example 1 99 One 100 15 Example 2 97 3 100 15 Example 3 95 5 100 15 Example 4 93 7 100 15 Example 5 90 10 100 15 Example 6 90 10 90 10 15 Example 7 90 10 100 15 Example 8 90 10 90 10 15 Example 9 90 5 5 90 5 5 15 Example 10 100 90 10 15 Example 11 100 93 7 15 Example 12 100 97 3 15 Example 13 100 99 One 15 Comparative Example 1 100 100 15 Comparative Example 2 85 15 100 15 Comparative Example 3 85 15 100 15 Comparative Example 4 85 15 85 15 15 Comparative Example 5 85 15 85 15 15 Comparative Example 6 100 85 15 15 BPDA: biphenyltetracarboxylic dianhydride
BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride
FDA-ADA: 4,4'-(9H-fluorene-9,9diyl)bis(4,1-phenylene)bis(4-aminobenzamide) (4,4'-(9H-fluorene-9, 9-diyl)bis(4,1-phenylene)bis(4-aminobenzamide)
PPD: para-phenylene diamine
BAFL: 9,9-bis (4-amino phenyl) fluorene
TFMB: 2,2'-bis(trifluoromethyl)benzidine

<Preparation of polyimide for measuring physical properties>

Air bubbles were removed from the polyamic acid compositions prepared in Examples and Comparative Examples by high-speed rotation of 1,500 rpm or more. Then, the degassed polyamic acid composition was applied to the glass substrate using a spin coater. Thereafter, a gel film was prepared by drying at a temperature of 120 ° C. for 30 minutes under a nitrogen atmosphere, and the gel film was heated at a rate of 2 ° C / min to 450 ° C. After heat treatment at 450 ° C. for 60 minutes, 30 ° C. It was cooled at a rate of 2° C./min to obtain a 10 μm polyimide film.

Thereafter, the polyimide film was peeled from the glass substrate by dipping in distilled water. The physical properties of the prepared polyimide film were measured using the following method, and the results are shown in Table 2 below.

Experimental Example 1 - Viscosity

Viscosity of the polyamic acid solutions prepared in Examples and Comparative Examples was measured using Haake's Rheostress 600 under conditions of a shear rate of 1/s, a temperature of 23° C., and a plate gap of 1 mm.

Experimental Example 2 - Light Transmittance

For the polyimide films of 10 μm prepared by curing the polyamic acid solutions of Examples and Comparative Examples, Perkin Elmer's UV / Vis Spectrophotometer (UV-Vis Spectrophotometer) using Lambda 465 model in transmittance mode The transmittance at 470 nm was measured.

Experimental Example 3 - CTE

TA's thermomechanical analyzer Q400 model was used, and after cutting the polyimide film into a width of 2 mm and a length of 10 mm, it was heated from room temperature to 500 ° C at a rate of 10 ° C / min while applying a tension of 0.05 N in a nitrogen atmosphere. After the temperature was raised, the slope of the section from 100 °C to 400 °C was measured while cooling at a rate of 10 °C/min.

Experimental Example 4 - Glass Transition Temperature

For the polyimide films prepared by curing the polyamic acid solutions of Examples and Comparative Examples, the rapidly expanding point at 10 °C/min condition was measured as an on-set point using TMA.

Experimental Example 5 - Thermal decomposition temperature (Td) of 1% by weight

TA's thermogravimetric analysis Q50 model was used, and the polyimide film was heated up to 150 °C at a rate of 10 °C/min under a nitrogen atmosphere, and then maintained at an isothermal temperature for 30 minutes to remove moisture. Thereafter, the temperature was raised to 600° C. at a rate of 10° C./min, and the temperature at which a weight loss of 1% occurred was measured.

Experimental Example 6 - Measurement of elongation

After cutting the polyimide films prepared by curing the polyamic acid solutions of Examples and Comparative Examples to a width of 10 mm and a length of 40 mm, the elongation can be measured by the ASTM D-882 method using Instron 5564 UTM equipment.

Experimental Example 7 - Measurement of elastic modulus and tensile strength

After cutting the polyimide film prepared by curing the polyamic acid solution of Examples and Comparative Examples into a width of 10 mm and a length of 40 mm, the elastic modulus and tensile strength were measured by ASTM D-882 method using Instron 5564 UTM equipment. can The cross head speed at this time can be measured under the condition of 50 mm/min.

division viscosity
(cP) permeability
(%) CTE
(ppm/℃) Tg
(℃) Td
(℃) elongation
(%) tensile strength
(MPa) elastic modulus
(GPa) Example 1 3,300 66 3 460 568 28 468 9.0 Example 2 4,200 70 3 460 568 28 397 8.1 Example 3 4,100 72 4 455 565 25 342 7.9 Example 4 3,000 74 4 455 563 23 303 7.8 Example 5 3,000 77 10 450 563 22 275 7.1 Example 6 3,500 83 14 455 558 20 263 7.0 Example 7 3,100 76 8 460 560 25 301 6.9 Example 8 3,800 79 12 460 555 20 265 7.0 Example 9 5,200 76 12 450 553 22 290 7.3 Example 10 4,800 75 13 450 558 25 334 7.5 Example 11 4,400 73 10 455 560 25 340 7.5 Example 12 3,500 71 5 460 565 26 378 8.0 Example 13 3,500 66 3 460 568 27 401 8.9 Comparative Example 1 3,000 65 3 470 570 30 520 9.4 Comparative Example 2 3,200 80 17 395 548 14 198 6.7 Comparative Example 3 3,400 76 18 410 545 17 224 6.8 Comparative Example 4 3,000 84 26 360 535 13 165 6.5 Comparative Example 5 4,000 82 24 390 531 13 186 6.7 Comparative Example 6 5,500 73 20 380 548 14 202 6.7

Claims (19)

A polyamic acid having a polymerization unit derived from a dianhydride monomer component and a diamine monomer component and a solvent, At least one monomer component of the dianhydride monomer component and the diamine monomer component includes a compound having a fluorene skeleton, A polyamic acid composition having a glass transition temperature of 430° C. or higher after curing. According to claim 1, The dianhydride monomer component and the diamine monomer component are polyamic acid composition comprising a compound having one or two benzene rings, respectively. According to claim 1, The dianhydride monomer component includes a compound having two or more benzene rings, The diamine monomer component is a polyamic acid composition comprising a compound having one benzene ring. According to claim 1, The content of the compound having a fluorene skeleton in the dianhydride monomer component is less than 15 mol% of the polyamic acid composition. According to claim 1, The content of the compound having a fluorene skeleton in the diamine monomer component is less than 15 mol% of the polyamic acid composition. According to claim 1, Among the dianhydride monomer components, the compound having a fluorene skeleton, 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF) or 4,4'-(9H-fluorene-9,9diyl)bis(4,1-phenylene))bis (4-aminobenzamide) (FDA-ADA) polyamic acid composition. According to claim 1, Among the diamine monomer components, the compound having a fluorene skeleton, A polyamic acid composition that is 9,9'-bis(4-aminophenyl)fluorene (BAFL) or 9,9-bis(4-amino-3fluorophenyl)fluorene (FFDA). According to claim 2, Among the dianhydride monomer components, compounds having one or two benzene rings are pyromellitic dianhydride (PMDA), 3,3',4,4'-biphenyltetracarboxylic dianhydride (s- BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) , At least one polyamic acid composition selected from the group consisting of oxydiphthalic dianhydride (ODPA) and 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6-FDA). According to claim 2, Compounds having one or two benzene rings among the diamine monomer components are 1,4-diaminobenzene (PPD), 1,3-diaminobenzene (MPD), 2,4-diaminotoluene, 2,6- Diaminotoluene, 4,4'-diaminodiphenyl ether (ODA), 4,4-diaminobenzanilide (4,4-DABA), 2,2-dimethylbenzidine (M-TOLIDINE), 3,3 -At least one polyamic acid composition selected from the group consisting of dimethylbenzidine (O-TOLIDINE) and 2,2'-bistrifluoromethylbenzidine (TFMB). According to claim 1, The boiling point of the solvent is 150 ℃ or more polyamic acid composition. According to claim 1, The solvent is N,N-diethylacetamide (DEAC), N,N-dimethylpropionamide (DMPA), 3-methoxy-N,N-dimethylpropanamide (KJCMPA), N-methyl-2-pyrroly Money (NMP) or a polyamic acid composition that is a combination thereof. According to claim 1, A polyamic acid composition having a solid content in the range of 5 to 30%. According to claim 1, A polyamic acid composition having a viscosity measured at a shear rate of 1,000 to 10,000 cP at a temperature of 23°C and 1s ^-1 . According to claim 1, A polyamic acid composition having a CTE of 20 ppm/° C. or less after curing. According to claim 1, A polyamic acid composition having a temperature (Td) of 550° C. or higher at which a weight loss of 1% after curing occurs. According to claim 1, A polyamic acid composition having a light transmittance of 60% or more at 470 nm after curing. A polyimide comprising a cured product of the polyamic acid composition according to claim 1. A transparent polyimide substrate for an oxide TFT prepared using the polyamic acid composition of any one of claims 1 to 16. A transparent polyimide substrate for LTPS prepared using the polyamic acid composition of any one of claims 1 to 16.