JP2020105504A - Polyamic acid, polyimide resin, and polyimide film - Google Patents

Abstract

To provide a polyimide film and a polyimide resin respectively having a high refractive index and low yellowness as mentioned in an embodiment of the invention, and a polyamic acid which can be used for production of the polyimide film and the polyimide resin respectively having the high refractive index and the low yellowness as mentioned in another embodiment of the invention.SOLUTION: A diamine monomer including a first monomer component with a size of 2.8-3.5 Å is used, and a dianhydride monomer with a size of 1.5-4.0 Å is used. Here, the monomer size is defined as the longest value appearing in measurement of a length toward y-axis direction after setting the widest plane of the monomer in parallel with the x-z plane based on the chemical calculation method.SELECTED DRAWING: Figure 1

Description

The present invention relates to a polyamic acid, a polyimide and a film containing the same, which can realize a high refractive index and a low yellowness.

Generally, a polyimide (PI) film is a film of a polyimide resin, and the polyimide resin can be produced by a reaction between a dianhydride compound and a diamine compound or a dianhydride compound and a diisocyanate compound.

Since polyimide film has excellent mechanical properties, heat resistance, and electrical insulation, it is used in a wide range of fields such as semiconductor insulating films, electrode protective films for display devices, and substrates for flexible printed wiring circuits. There is.

In general, a polyimide resin is colored brown and yellow due to a high aromatic ring density, has a low light transmittance in the visible light region, and has a large birefringence, so that there is a limit to its use in optical members. is there.

U.S. Pat. 2003-0009437 discloses a polyimide produced from an aromatic dianhydride and an aromatic diamine and having improved transparency and hue transparency in a range in which thermal characteristics are not significantly deteriorated. However, such a polyimide is insufficient in terms of mechanical properties, heat resistance and refractive index for use in a display device or lighting equipment.

Recently, an organic light emitting diode (OLED, in particular, an active type organic light emitting diode (AMOLED)) is used to improve efficiency of a display device or a lighting device.

A display device or a lighting device including an organic light emitting diode (OLED) has a multilayer laminated structure. Therefore, the light generated from the organic light emitting diode needs to pass through the multi-layered laminated structure in order to be emitted to the outside of the display device or the lighting device. However, light generated in the organic light emitting diode may be lost due to a light guide effect or total reflection in a process of passing through the multilayer laminated structure. As a result, the external quantum efficiency of organic light emitting diodes is currently at a low level.

In order to use a polyimide resin or a polyimide film as an insulating layer or an optical film of a display device or a lighting device including an organic light emitting diode, it has a high refractive index and heat resistance similar to the refractive index of a substance used for an electrode. There is a need. However, the transparent polymer material has a problem that it is difficult to have a refractive index of 1.70 or more due to the electronic characteristics of the internal constituent molecules.

An embodiment of the present invention aims to provide a polyimide resin and a polyimide film having low yellowness and high refractive index.

Another embodiment of the present invention aims to provide a polyamic acid that can be used to prepare a polyimide film having low yellowness and high refractive index.

An embodiment of the present invention to solve the above problems is obtained by the reaction of a diamine monomer and a dianhydride monomer, wherein the diamine monomer includes a first monomer component having a size of 2.8 to 3.5Å, The size of the dianhydride monomer is 1.5 to 4.0Å, and the size of the monomer is measured by using a molecular modeling program Gaussian 09, and Z-matrix coordinate chemistry. Provide a polyamic acid, defined as the longest value that appears when the length in the y-axis direction is measured after the widest plane of the monomer is located parallel to the xz plane based on the calculation method.

The first monomer component includes trans-1,4-cyclohexanediamine (trans-1,4-Cyclohexane diamine, tCHD), 1,4-cyclohexanediamine (1,4-Cyclohexane diamine, 14CHD), 1,3-cyclohexane. From diamine (1,3-Cyclohexaneamine, 13CHD), 1,2-Cyclohexanediamine (1,2-Cyclohexanediamine, 12CHD) and 2-fluoro-1,4-cyclohexanediamine (2-Fluoro-1,4-Cyclohexamine diamine). Includes one or more selected.

The dianhydride monomer may be biphenyl tetracarboxylic acid dianhydride (3,3,4,4-biphenyltetracarboxylic dianhydride, BPDA), pyromellitic acid dianhydride (1,2,4,5-benzenetetracarboxylic carboxylic acid carboxylic acid). , Benzophenone tetracarboxylic acid dianhydride (3,3,4,4-benzophenone tetracarboxy dianhydride, BTDA), oxydiphthalic acid dianhydride (4,4-Oxydiphthalic dianhydride, ODPA) and bisdicarboxydihydroxyphenoxy dihydroxide (4) -Bis(3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, BDSDA).

The diamine monomer may further include a second monomer component having a size of 1.5 to 1.8Å.

The second monomer component includes p-phenylenediamine (para-phenylene diamine, pPDA), m-phenylenediamine (meta-phenylene diamine, mPDA), 2-chloro-1,4-phenylenediamine (2-Chloro-1, 4-phenylenediamine), 2,5-dichloro-1,4-phenylenediamine (2,5-Dichlororo-1,4-phenylenediamine), 2-fluoro-1,4-phenylenediamine (2-Fluoro-1,4-) phenylenediamine) and 2,3,5,6-tetrafluoro-1,4-phenylenediamine (2,3,5,6-Tetrafluoro-1,4-phenylenediamine).

The second monomer component may be included in an amount of 10 to 50 mol% based on the total weight of the diamine monomer.

The diamine monomer may further include a third monomer component having a size of 2.3 to 2.6Å.

The third monomer component includes 4-aminobenzoic acid 4-aminophenyl ester (4-aminophenester ester, 4ABA), 4,4′-diaminobenzophenone (4,4′-Diaminobenzophenone), benzidine and Benzodine. One or more kinds selected from 4,4'-diaminodiphenylmethane (4,4'-Diaminodiphenylmethane) are included.

The third monomer component is included in an amount of 10 to 50 mol% based on the total weight of the diamine monomer.

Another embodiment of the present invention provides a polyimide resin obtained by the imidization reaction of the polyamic acid.

Yet another embodiment of the present invention provides a polyimide film formed by the imidization reaction of the polyamic acid.

The polyimide film may have a refractive index of 1.67 or higher.

The polyimide film may have a yellowness index (YI) of 20 or less.

The polyimide film may have a coefficient of thermal expansion (CTE) of 20 ppm/° C. or less at 50 to 250° C.

The polyimide film has a transmittance of 83% or more at 550 nm.

Yet another embodiment of the present invention provides a lighting device including the polyimide film.

Yet another embodiment of the present invention provides a display device including the polyimide film.

Yet another embodiment of the present invention provides a display device including the polyimide resin.

According to the present invention, a polyimide film having low yellowness and high refractive index is provided.

FIG. 1 is a schematic diagram showing the size measurement of biphenyltetracarboxylic acid dianhydride (3,3,4,4-Biphenyltetracarboxylic dianhydride, BPDA). FIG. 6 is a schematic cross-sectional view of a display device according to another exemplary embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the examples described below are presented for the purpose of exemplifying the present invention to facilitate a clear understanding of the present invention, and do not limit the scope of the present invention.

The shapes, sizes, ratios, angles, numbers and the like disclosed in the drawings for explaining the embodiments of the present invention are mere examples, and the present invention is not limited to the matters disclosed in the drawings. In describing the present invention, a detailed description of known related art will be omitted when it may make the subject matter of the present invention unnecessarily obscure.

When “including”, “having”, “consisting of” and the like are used herein, other parts may be added, unless the expression “only” is given. When a component is expressed in the singular, the plural is included unless otherwise specified. Also, when interpreting a component, it is construed as including an error range even if not explicitly stated.

In the description of the temporal relationship, for example, when the temporal context is described by “after”, “following”, “next”, “before”, etc., “immediately” or Unless the expression “directly” is used, it may include the case where it is not continuous.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are only used to distinguish one element from another. Therefore, the first component referred to below may be the second component within the technical idea of the present invention.

It is to be understood that the term "at least one" includes any combination that can be presented from one or more related items. For example, “at least one of the first item, the second item, and the third item” means not only the first item, the second item, or the third item, but also the first item, the second item, and the third item. It can mean any combination of items that can be presented by two or more of them.

The respective features of the respective embodiments of the present invention can be partially or wholly combined or combined with each other, and various technical interlocking and driving are possible, and the respective embodiments are independent of each other. May be carried out together or may be carried out together in association with each other.

One embodiment of the present invention provides a polyamic acid obtained by reacting a diamine monomer and a dianhydride monomer. The diamine monomer includes a first monomer component having a size of 2.8 to 3.5Å. The size of the dianhydride monomer is 1.5 to 4.0Å.

According to one embodiment of the present invention, monomer size is measured using the molecular modeling program Gaussian 09. Specifically, a molecular modeling program Gaussian 09 is used to measure the monomer size, and the widest surface of the monomer is referred to as an xz surface based on a Z-matrix coordinate chemical calculation method. The monomer size D is defined as the longest value that appears when the lengths in the y-axis direction are measured after being positioned in parallel.

Referring to FIG. 1, a portion having the largest area of a monomer is measured by a Z-matrix coordinate chemical calculation method using a molecular modeling program Gaussian 09, and a portion having the largest area is defined as an xz plane. They are located in parallel, and the value obtained by measuring the farthest distance based on the y axis is the monomer size D.

According to one embodiment of the present invention, the diamine monomer comprises a first monomer component having a monomer size of 2.8-3.5Å. As the first monomer component, trans-1,4-cyclohexanediamine (trans-1,4-Cyclohexane diamine, tCHD), 1,4-cyclohexanediamine (1,4-Cyclohexane diamine, 14CHD), 1,3-cyclohexane Diamine (1,3-Cyclohexaneamine, 13CHD), 1,2-Cyclohexanediamine (1,2-Cyclohexaneamine, 12CHD) and 2-Fluoro-1,4-cyclohexanediamine (2-Fluoro-1,4-Cyclohexamine diamine) Contains at least one. However, the embodiment of the present invention is not limited thereto, and another diamine monomer having a monomer size of 2.8 to 3.5Å may be used as the first monomer component according to the embodiment of the present invention. May be.

According to one embodiment of the present invention, for convenience, trans-1,4-cyclohexanediamine (tCHD) and 1,4-cyclohexanediamine (14CHD) are distinguished. When it is not distinguished whether 1,4-cyclohexanediamine (14CHD) has a cis-type structure or a trans-type structure, it is expressed as 1,4-cyclohexanediamine (14CHD), and particularly refers to 1,4-cyclohexanediamine having a trans structure. Is called trans-1,4-cyclohexanediamine (tCHD).

According to one embodiment of the present invention, the dianhydride monomer has a monomer size of 1.5-4.0Å. Examples of the dianhydride monomer having a monomer size of 1.5 to 4.0 Å include, for example, biphenyltetracarboxylic acid dianhydride (3,3,4,4-biphenyltetracarboxylic dianhydride, BPDA), pyromellitic dianhydride (1,2, 4,5-benzene tetracarboxy dianhydride, pyromelliticic acid dianhydride, PMDA, benzophenone tetracarboxylic acid dianhydride (3,3,4,4-Benthioxy phthalic oxydihydroxide) And bisdicarboxyphenoxydiphenyl sulfide dianhydride (4,4-bis(3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, BDSDA). However, one embodiment of the present invention is not limited thereto, and another dianhydride monomer having a monomer size of 1.5 to 4.0Å may be used as the dianhydride monomer according to one embodiment of the present invention. May be.

The polyamic acid of the present invention can be produced by reacting a diamine monomer and a dianhydride monomer. The polyamic acid prepared by the first monomer component, which is a diamine monomer having a monomer size of 2.8 to 3.5Å, and the dianhydride monomer having a monomer size of 1.5 to 4.0Å, may have a front crystal structure. It can have a tilt angle and a dihedral angle close to 0, and can form a non-bonded structure. As a result, the polyamic acid can have high refractive properties, low yellowness, and transparent properties.

According to one embodiment of the present invention, the diamine monomer comprises, in addition to the first monomer component, a second monomer component having a monomer size of 1.5 to 1.8Å, and a monomer of 2.3 to 2.6Å. At least one third monomer component having a size may be further included.

When the diamine monomer further comprises at least one of a second monomer component and a third monomer component in addition to the first monomer component, the polyamic acid prepared by the diamine monomer and dianhydride has low CTE and yellowness. And can be used for producing a polyimide film having a high refractive index.

Examples of the second monomer component having a monomer size of 1.5 to 1.8Å include p-phenylene diamine (pPDA), m-phenylene diamine (mPDA), and 2-chloro. -1,4-phenylenediamine (2-Chloro-1,4-phenylenediamine), 2,5-dichloro-1,4-phenylenediamine (2,5-Dichlororo-1,4-phenylenediamine), 2-fluoro-1 ,4-phenylenediamine (2-Fluoro-1,4-phenylenediamine) and 2,3,5,6-tetrafluoro-1,4-phenylenediamine (2,3,5,6-Tetrafluoro-1,4-phenylenediamine) ). However, the embodiment of the present invention is not limited thereto, and another diamine monomer having a monomer size of 1.5 to 1.8Å may be used as the second monomer component according to the embodiment of the present invention. May be.

The second monomer component may be included in an amount of 50 mol% or less based on the total weight of the diamine monomer. For example, the second monomer component may be included in an amount of 10 to 50 mol%, more specifically, an amount of 10 to 40 mol% based on the total weight of the diamine monomer. Alternatively, the second monomer component may be included in a content of 20 to 40 mol% based on the total weight of the diamine monomer.

The second monomer component has a small monomer size, can play a role of reducing intermolecular distance in the polyimide resin and the polyimide film, and can play a role of increasing the density of polymer chains. As a result, the second monomer component can improve the refractive index and heat resistance of the polyimide film.

Examples of the third monomer component having a monomer size of 2.3 to 2.6Å include 4-aminobenzoic acid 4-aminophenyl ester (4-Aminobenzoic acid 4-aminophenyl ester, 4ABA), 4,4′-diaminobenzophenone. It may include at least one of (4,4′-diaminobenzophenone), benzidine, and 4,4′-diaminodiphenylmethane (4,4′-Diaminodiphenylmethane). However, the embodiment of the present invention is not limited thereto, and another diamine monomer having a monomer size of 2.3 to 2.6Å may be used as the third monomer component according to the embodiment of the present invention. May be.

The third monomer component may be included in a content of 10 to 50 mol% based on the total weight of diamine. Specifically, the third monomer component may be included in an amount of 30 to 50 mol%, more specifically 40 to 50 mol%, based on the total weight of the diamine.

The third monomer component has a smaller monomer size than the first monomer component, can play a role of reducing the intermolecular distance in the polyimide resin and the polyimide film, and can reduce the resonance phenomenon in the molecule. .. As a result, the third monomer component can play a role of increasing the refractive index of the polyimide film and a role of preventing an increase in yellowness.

According to an embodiment of the present invention, when a second monomer component or a third monomer component is added as a diamine monomer in addition to the first monomer component, a polyamic acid produced by a diamine monomer and a dianhydride monomer and It is possible to reduce the yellowness of the polyimide film produced from such a polyamic acid and improve the refractive index.

According to one embodiment of the present invention, when a first monomer component, a second monomer component and a third monomer component are used together as a diamine monomer, a polyimide film having a yellowness of 10 or less and a refractive index of 1.75 or more is obtained. It can be manufactured.

According to one embodiment of the present invention, the diamine monomer may be more than 0 to 80 wt% of the first monomer component, 10 to 50 wt% of the second monomer component and 10 to 50 wt% based on the total weight of the diamine monomer. % Third monomer component. More specifically, the diamine monomer comprises 50 to 60% by weight of the first monomer component, 10 to 40% by weight of the second monomer component, and 10 to 40% by weight of the third monomer component, relative to the total weight of the diamine monomer. A monomer component can be included.

According to another embodiment of the present invention, a polyimide resin can be produced by subjecting the above polyamic acid to an imidization reaction.

According to another embodiment of the present invention, a polyimide film including the above polyimide can be provided.

In the examples of the present invention, the polyimide resin means a compound in which polyamic acid is formed by imidization reaction, and the polyimide film means a product in which the polyimide resin is formed into a film form.

The polyimide film according to an embodiment of the present invention may have a coefficient of thermal expansion (CTE) of 20 ppm/° C. or less at 50 to 250° C. According to another embodiment of the present invention, the polyimide film may have a coefficient of thermal expansion (CTE) of 10 ppm/°C or less at 50 to 250°C. More specifically, the polyimide film can have a coefficient of thermal expansion of 8 ppm/° C. or less at 50 to 250° C.

According to another embodiment of the present invention, the polyimide film may have a coefficient of thermal expansion of 4.7 to 7.4 ppm/°C at 50 to 250°C.

According to another embodiment of the present invention, the polyimide film may have a transmittance of 83% or more at 550 nm when measured with a UV spectrometer based on a thickness of 10 to 100 μm. Further, the polyimide film may have an average transmittance of 83% or more at 380 to 780 nm when the transmittance is measured with a UV spectrometer based on the thickness of 10 to 100 μm.

The polyimide film according to another embodiment of the present invention may have a yellowness of 20 or less based on a film thickness of 10 to 100 μm.

In addition, the polyimide film according to another embodiment of the present invention may have a yellowness of 13 or less, more specifically 10 or less, based on the film thickness of 10 to 100 μm.

For example, a polyimide film according to another embodiment of the present invention may have a yellowness index (YI) of 12.5 or less.

Polyimide film according to an embodiment of the present invention having a thermal expansion coefficient, light transmittance and yellowness as described above, unlike the existing polyimide film having a yellow color, a protective film of a display device, a diffusion plate, a coating film, It can be used in fields requiring transparency such as an interlayer insulating film, a gate insulating film and a liquid crystal alignment film. For example, when the transparent polyimide according to the embodiment of the present invention is used as the liquid crystal alignment film, a liquid crystal display device having a high contrast ratio can be manufactured.

In addition, the polyimide film according to an embodiment of the present invention can be used as a substrate of a flexible display device, and can also be used in OLED devices, lighting devices, video device devices, hard coating films, and the like.

Physical properties such as the coefficient of thermal expansion, the transmittance, and the yellowness described above may be measured with a polyimide film having a thickness in the range of 10 to 100 μm, for example, a film having a thickness of 11 μm, 12 μm, 13 μm,... 100 μm, Each of the physical property ranges can be satisfied by measuring each film within the above thickness. Here, the thickness range of the polyimide film is for measuring physical properties, and does not limit the thickness of the polyimide film according to an embodiment of the present invention unless otherwise specified.

The polyimide film according to an exemplary embodiment of the present invention may have a refractive index of 1.67 or higher.

The refractive index of the polyimide film according to one embodiment of the present invention is 1.67 when measured in TE (Transverse Electric) mode at 532 nm using a birefringence analyzer (Prism Coupler, Sairon SPA4000), for example. It can be, specifically 1.70 or more, more specifically 1.75, and 1.77 or more. As described above, since the polyimide film according to the embodiment of the present invention has a high refractive index similar to ITO (InSnO) used as an electrode of a display device, it is applied to a lighting device and has an excellent light extraction effect. Can be expressed.

For example, a polyimide film according to an exemplary embodiment of the present invention may have a refractive index of 1.74-1.81.

Another embodiment of the invention provides a method of making a polyamic acid.

According to another embodiment of the present invention, a method for producing a polyamic acid comprises a step of producing a diamine solution (S10), and a diamine solution produced in the production step (S10) having a monomer size of 1 or less. It includes a reaction step (S20) of adding and reacting a dianhydride monomer of 0.5 to 4.0Å.

The manufacturing step (S10) of manufacturing the diamine solution includes a step of adding a diamine monomer to a solvent and dissolving the monomer. As the diamine monomer, the first monomer having a monomer size of 2.8 to 3.5Å can be used alone. Further, as the diamine monomer, the first monomer having a monomer size of 2.8 to 3.5Å, the second monomer having a monomer size of 1.5 to 1.8Å and the monomer size of 2.3 to 2.6Å A monomer in which one or more kinds of a certain second monomer are mixed may be used.

The diamine monomer may include a second monomer having a monomer size of 1.5 to 1.8Å in an amount of 10 to 40 mol% based on the total weight of the diamine monomer. In this case, it may be advantageous for the effect of increasing the refractive index of the polyimide film and for preventing an increase in yellowness in terms of structural characteristics.

The second monomer having a monomer size of 2.3 to 2.6Å may be included in an amount of 10 to 50 mol% based on the total weight of the diamine monomer. In this case, it may be advantageous for the effect of increasing the refractive index of the polyimide film and for preventing an increase in yellowness in terms of structural characteristics.

As the solvent, m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO), acetone, diethyl acetate, diethylformamide (DEF), diethylacetamide (DMF). One or more polar solvents selected from DEA), propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate (PGMEA) can be used. In addition to this, a low boiling point solution such as tetrahydrofuran (THF) or chloroform, or a low absorption solvent such as γ-butyrolactone may be used. However, the solvent is not limited to the types mentioned above, and may be used alone or in combination of two or more depending on the purpose.

There is no particular limitation on the content of the solvent. Due to the degree of polymerization and convenience of the process, the content of the solvent can be adjusted to 70-95% by weight of the total solution, more specifically 75-95% by weight.

Next, the reaction step (S20) is a step of adding a dianhydride monomer having a monomer size of 1.5 to 4.0Å to the diamine solution produced in the production step (S10) to cause a reaction.

The reaction conditions in the reaction step (S20) are not particularly limited, but an inert gas such as argon or nitrogen can be used in the reaction, and the reaction temperature is 0 to 80° C., more specifically 60 to It is 80° C. and the reaction time is 1 to 48 hours, more specifically 1 to 5 hours. When the reaction step (S20) is performed under the above conditions, the polyamic acid can be sufficiently polymerized.

The method for producing a polyimide film from the polyamic acid produced by such a production method is not particularly limited, and a known method can be applied. As a method of imidizing the polyamic acid, there are a thermal imidization method and a chemical imidization method. Of these, for example, the chemical imidization method can be applied. Specifically, the solution obtained by the chemical imidization method may be precipitated, purified, dried, and then dissolved in a solvent again before use. Here, the solvent may be the same as the solvent mentioned above. In the chemical imidization method, 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 are applied to a polyamic acid solution. It is a method to let. The chemical imidization method and the thermal imidization method may be used in combination, and the heating conditions may vary depending on the type of polyamic acid solution, the thickness of the film, and the like.

After the polyimide produced by the chemical imidization method is precipitated and dried to produce a powdery polyimide, the powdery polyimide is again dissolved in a solvent to form a polyimide solution, and then the polyimide solution is applied to a support. A polyimide film is obtained by forming a film on a support by drying and heat treatment. The film forming temperature of the applied film may be, for example, 250 to 500° C., and a glass plate, an aluminum foil, a circulating stainless belt, a stainless drum or the like can be used as the support.

The time required to form a film varies depending on the temperature, the type of support, the amount of the polyimide solution applied, and the mixing conditions of the catalyst, and is not limited to a certain time. For example, it can be performed in the range of 5 minutes to 30 minutes.

The heat treatment temperature may be 100 to 500° C., and the heat treatment time may be 100 to 180 minutes. After heat treatment to complete the drying and imidization, the polyimide film is peeled off from the support.

The residual volatile component of the heat-treated film is 5% or less, preferably 3% or less.

The thickness of the obtained polyimide film is not particularly limited, but may be in the range of 10 to 100 μm.

[Example]
Hereinafter, the present invention will be described in more detail with reference to examples. It will be apparent to those of ordinary skill in the art that these examples are merely illustrative of the present invention and that the scope of the present invention is not to be construed as limited by these examples. ..

<Example 1>
As a reactor, a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler was filled with 273.321 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen. 11.419 g of tCHD as the first monomer component was dissolved. Then, 29.422 g of BPDA, which is a dianhydride monomer, was added and the temperature was raised to 70° C., and then the temperature was maintained for 1.5 hours. As a result, a polyamic acid solution having a solid content concentration of 13% 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 cured up to 310° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film. Here, tCHD and BPDA used were as shown in Table 2 below as a result of measuring the monomer size using a molecular modeling program Gaussian 09.

<Example 2>
As a reactor, a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler was filled with N-methyl-2-pyrrolidone (NMP) 298.613 g while passing nitrogen. 2.163 g of pPDA as the second monomer component was dissolved. After that, 9.135 g of tCHD as the first monomer component was dissolved. Then, 29.422 g of BPDA, which is a dianhydride monomer, was added, the temperature was raised to 70° C., and the temperature was maintained for 1 hour. As a result, a polyamic acid solution having a solid content of 12% 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 cured up to 330°C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film. Here, pPDA, tCHD and BPDA used were as shown in Table 2 below as a result of measuring the monomer size using the molecular modeling program Gaussian 09.

<Example 3>
As a reactor, a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler was charged with 298.170 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen. Then, 3.244 g of pPDA as the second monomer component was dissolved. After that, 7.993 g of tCHD as the first monomer component was dissolved. Then, 29.422 g of BPDA, which is a dianhydride monomer, was added, the temperature was raised to 70° C., and the temperature was maintained for 1 hour. As a result, a polyamic acid solution having a solid content of 12% 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 cured up to 310° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film. Here, pPDA, tCHD and BPDA used were as shown in Table 2 below as a result of measuring the monomer size using the molecular modeling program Gaussian 09.

<Example 4>
As a reactor, a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler was filled with N-methyl-2-pyrrolidone (NMP) 297.726 g while passing nitrogen. , And the second monomer component, pPDA (4.326 g) was dissolved. Then, 6.851 g of tCHD, which is the first monomer component, was dissolved. Then, 29.422 g of BPDA, which is a dianhydride monomer, was added, the temperature was raised to 70° C., and the temperature was maintained for 1 hour. As a result, a polyamic acid solution having a solid content of 12% 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 cured up to 310° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film. Here, pPDA, tCHD and BPDA used were as shown in Table 2 below as a result of measuring the monomer size using the molecular modeling program Gaussian 09.

<Example 5>
As a reactor, after filling a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser with N-methyl-2-pyrrolidone (NMP) 266.011 g while passing nitrogen, 10.956 g of 4ABA, which is the third monomer component, was dissolved. After that, 8.222 g of tCHD as the first monomer component was dissolved. Then, 35.306 g of BPDA, which is a dianhydride monomer, was added, the temperature was raised to 70° C., and the temperature was maintained for 1 hour. As a result, a polyamic acid solution having a solid content concentration of 17% 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 cured up to 310° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film. Here, 4ABA, tCHD and BPDA used were as shown in Table 2 below as a result of measuring the monomer size using a molecular modeling program Gaussian 09.

<Example 6>
As a reactor, after filling a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser with N-methyl-2-pyrrolidone (NMP) 269.352 g while passing nitrogen, 12.326 g of 4ABA, which is the third monomer component, was dissolved. Then, 7.537 g of tCHD, which is the first monomer component, was dissolved. Then, 35.306 g of BPDA, which is a dianhydride monomer, was added, the temperature was raised to 70° C., and the temperature was maintained for 1 hour. As a result, a polyamic acid solution having a solid content concentration of 17% 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 cured up to 310° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film. Here, 4ABA, tCHD and BPDA used were as shown in Table 2 below as a result of measuring the monomer size using a molecular modeling program Gaussian 09.

<Example 7>
As a reactor, after charging N-methyl-2-pyrrolidone (NMP) 272.693 g while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler, 13.695 g of 4ABA which is the third monomer component was dissolved. Then, 6.851 g of tCHD, which is the first monomer component, was dissolved. Then, 35.306 g of BPDA, which is a dianhydride monomer, was added, the temperature was raised to 70° C., and the temperature was maintained for 1 hour. As a result, a polyamic acid solution having a solid content concentration of 17% 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 cured up to 310° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film. Here, 4ABA, tCHD and BPDA used were as shown in Table 2 below as a result of measuring the monomer size using a molecular modeling program Gaussian 09.

<Example 8>
As a reactor, a nitrogen-containing 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a condenser was filled with N-methyl-2-pyrrolidone (NMP) 297.282 g, while passing nitrogen. 5.407 g of pPDA which is the second monomer component was dissolved. Then, 5.710 g of tCHD, which is the first monomer component, was dissolved. Then, 29.422 g of BPDA, which is a dianhydride monomer, was added, the temperature was raised to 70° C., and the temperature was maintained for 1 hour. As a result, a polyamic acid solution having a solid content of 12% 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 cured up to 310° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film. Here, pPDA, tCHD and BPDA used were as shown in Table 2 below as a result of measuring the monomer size using the molecular modeling program Gaussian 09.

<Examples 9 to 19>
In the same manner as in Example 2, a polyimide film was prepared using the diamine component and the dianhydride component according to the contents shown in Table 1, and the polyimide films were designated as Examples 9 to 17.

Further, tCHD, pPDA and 4ABA were used as the diamine monomer, and BPDA was used as the dianhydride monomer to prepare a polyimide film, which was designated as Example 18. A polyimide film was prepared using tCHD, pPDA and 4ABA as the diamine monomer and PMDA as the dianhydride monomer, and this was designated as Example 19.

In Examples 18 and 19, pPDA and 4ABA were first dissolved and then tCHD was dissolved in the step of producing the diamine monomer solution.

The monomer composition according to Examples 1 to 19 is as shown in Table 1. The monomer size of each component used in Examples 1 to 19 is shown in Table 2.

<Comparative Example 1>
After the reactor was filled with 295.064 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen through a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler. 10.814 g of pPDA was dissolved. Then, 29.422 g of BPDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content of 12% by weight was obtained. After completion of the reaction, the obtained solution was applied to a glass plate, treated with hot air of 80° C. for 20 minutes, and cured up to 380° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

<Comparative example 2>
As a reactor, a 500 ml reactor equipped with a stirrer, a nitrogen injection device, a dropping funnel, a temperature controller and a cooler was filled with 280.597 g of N-methyl-2-pyrrolidone (NMP) while passing nitrogen. 25.108 g of 4ABA was dissolved. Then, 32.364 g of BPDA was added and reacted for 15 hours. As a result, a polyamic acid solution having a solid content concentration of 17% 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 cured up to 310° C. Then, it was gradually cooled and separated from the glass plate to obtain a polyimide film.

Physical properties of the polyimide films produced in the above Examples 1 to 19 and Comparative Examples 1 and 2 were evaluated by the following methods, and the results are shown in Table 3 below.

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

(2) Yellowness (YI) measurement The yellowness was measured according to the ASTM E313 standard using a UV spectrometer (Konica Minolta, CM-3700d).

(3) Measurement of thermal expansion coefficient (CTE) The linear thermal expansion coefficient at 50 to 250° C. was measured twice by TMA method using TMA (TA Instrument Co., Q400). The size of the test piece was 4 mm×24 mm, the load was 0.02 N, and the temperature rising rate was 5° C./min.

Since the film may be formed and residual stress may remain in the film due to heat treatment, after the residual stress was completely removed in the first operation (Run), the second value was presented as an actual measurement value.

(4) Measurement of Refractive Index A birefringence analyzer (Prism Coupler, Sairon SPA4000) was used to measure at 532 nm in a TE (Transverse Electric) mode.

As shown in Table 1, Examples 1 to 8 include diamine (tCHD) including a monomer having a size of 2.8 to 3.5Å and dian including a monomer having a size of 1.5 to 4.0Å. It was confirmed to have excellent physical properties as compared with Comparative Examples 1 and 2, which contained hydride (BPDA) and did not contain diamine containing a monomer of 2.8 to 3.5Å size. On the other hand, in the case of the films produced in Comparative Examples 1 and 2, the refractive index was too high and exceeded the measurement limit of the equipment, so the refractive index was not measured.

From this, it was found that the constitution of the present invention must be satisfied as in Examples 1 to 19 in order to satisfy all the physical properties of yellowness, transmittance, thermal expansion coefficient, and refractive index.

FIG. 2 is a schematic sectional view of a display device according to another embodiment of the present invention.

The display device according to another embodiment of the present invention includes a substrate 110, a thin film transistor 200, and an organic light emitting device 270 connected to the thin film transistor 200.

Referring to FIG. 2, the display device includes a substrate 110, a thin film transistor 200 disposed on the substrate 110, and a first electrode 271 connected to the thin film transistor 200. The display device also includes an organic light emitting layer 272 disposed on the first electrode 271 and a second electrode 273 disposed on the organic light emitting layer 272. The display device shown in FIG. 2 is an organic light emitting display device.

The substrate 110 can be made of plastic. Specifically, the substrate 110 may be made of a polyimide resin or a polyimide film according to an exemplary embodiment of the present invention.

The buffer layer 121 is disposed on the substrate 110. In addition, the light blocking layer 180 may be disposed between the substrate 110 and the buffer layer 121.

The thin film transistor 200 is disposed on the buffer layer 121 on the substrate 110. The thin film transistor 200 includes a semiconductor layer 130 on the buffer layer 121, a gate electrode 140 insulated from the semiconductor layer 130 and overlapping at least a part of the semiconductor layer 130, a source electrode 150 connected to the semiconductor layer 130, and a source electrode 150. And a drain electrode 160 that is connected to the semiconductor layer 130 with a space therebetween.

Referring to FIG. 2, the gate insulating film 122 is disposed between the gate electrode 140 and the semiconductor layer 130. The gate insulating layer 122 may be made of a polyimide resin or a polyimide film according to an exemplary embodiment of the present invention.

The planarization layer 190 is disposed on the thin film transistor 200 and planarizes the upper portion of the substrate 110. The planarization layer 190 may be made of a polyimide resin or a polyimide film according to an exemplary embodiment of the present invention.

The first electrode 271 is disposed on the flattening film 190. The first electrode 271 is connected to the drain electrode 160 of the thin film transistor 200 through a contact hole formed in the planarization film 190.

The bank layer 250 is disposed on the first electrode 271 and the planarization layer 190 and defines a pixel region or a light emitting region. For example, the pixel region may be defined by the bank layer 250 by arranging the bank layer 250 in a boundary region between a plurality of pixels in a matrix structure. The bank layer 250 may be made of a polyimide resin or a polyimide film according to an exemplary embodiment of the present invention.

The organic light emitting layer 272 is disposed on the first electrode 271. The organic light emitting layer 272 may also be disposed on the bank layer 250.

The organic light emitting layer 272 may include one light emitting layer, or may include two light emitting layers stacked one above the other. Light having any one of red, green, and blue may be emitted from the organic light emitting layer 272, or white light may be emitted.

The second electrode 273 is disposed on the organic light emitting layer 272.

The first electrode 271, the organic light emitting layer 272, and the second electrode 273 may be stacked to form the organic light emitting device 270.

Although not shown, when the organic light emitting layer 272 emits white light, each pixel includes a color filter for filtering the white light emitted from the organic light emitting layer 272 according to wavelength. be able to. The color filter is formed on the moving path of light.

The polyimide film according to the embodiment of the present invention can be applied as a window covering the light emitting surface of the display device shown in FIG.

Claims (18)

Obtained by the reaction of a diamine monomer and a dianhydride monomer,
The diamine monomer includes a first monomer component having a size of 2.8 to 3.5Å,
The size of the dianhydride monomer is 1.5 to 4.0Å,
The monomer size is measured using a molecular modeling program, Gaussian 09, and based on the Z-matrix coordinate chemical calculation method, the broadest surface of the monomer is defined as an xz plane. Polyamic acid, defined as the longest value that appears when measuring the length in the y-axis direction after being positioned in parallel. The first monomer component is trans-1,4-cyclohexanediamine (trans-1,4-Cyclohexane diamine, tCHD), 1,4-cyclohexanediamine (1,4-Cyclohexane diamine, 14CHD), 1,3-cyclohexane. From diamine (1,3-Cyclohexaneamine, 13CHD), 1,2-cyclohexanediamine (1,2-Cyclohexanediamine, 12CHD) and 2-fluoro-1,4-cyclohexanediamine (2-Fluoro-1,4-Cyclohexamine diamine). The polyamic acid according to claim 1, comprising at least one selected. The dianhydride monomer may be biphenyltetracarboxylic acid dianhydride (3,3,4,4-biphenyltetracarboxylic dianhydride, BPDA), pyromellitic acid dianhydride (1,2,4,5-benzenetetracarboxylic carboxylic acid carboxylic acid). Benzophenone tetracarboxylic acid dianhydride (3,3,4,4-Benzophenone tetracarboxy dianhydride, BTDA), oxydiphthalic acid dianhydride (4,4-Oxydiphthalic dianhydride, ODPA) and bisdicarboxyphenoxydiphenyldioxide The polyamic acid according to claim 1, comprising one or more selected from bis(3,4-dicarboxyphenoxy) diphenyl sulfide dianhydride, BDSDA). The polyamic acid according to claim 1, wherein the diamine monomer further comprises a second monomer component having a size of 1.5 to 1.8Å. The second monomer component includes p-phenylenediamine (para-phenylene diamine, pPDA), m-phenylenediamine (meta-phenylene diamine, mPDA), 2-chloro-1,4-phenylenediamine (2-Chloro-1, 4-phenylenediamine), 2,5-dichloro-1,4-phenylenediamine (2,5-Dichlororo-1,4-phenylenediamine), 2-fluoro-1,4-phenylenediamine (2-Fluoro-1,4-) phenylenediamine) and 2,3,5,6-tetrafluoro-1,4-phenylenediamine (2,3,5,6-Tetrafluoro-1,4-phenylenediamine), and at least one selected from the group consisting of The polyamic acid described. The polyamic acid according to claim 4, wherein the second monomer component is included in an amount of 10 to 50 mol% based on the total weight of the diamine monomer. The polyamic acid according to claim 1, wherein the diamine monomer further comprises a third monomer component having a size of 2.3 to 2.6Å. The third monomer component includes 4-aminobenzoic acid 4-aminophenyl ester (4-aminophenester ester, 4ABA), 4,4′-diaminobenzophenone (4,4′-Diaminobenzophenone), benzidine and Benzodine. The polyamic acid according to claim 7, which comprises one or more kinds selected from 4,4'-diaminodiphenylmethane (4,4'-Diaminodiphenylmethane). The polyamic acid according to claim 7, wherein the third monomer component is included in an amount of 10 to 50 mol% based on the total weight of the diamine monomer. A polyimide resin obtained by the imidization reaction of the polyamic acid according to claim 1. A polyimide film formed by the imidization reaction of the polyamic acid according to claim 1. The polyimide film according to claim 11, which has a refractive index of 1.67 or more. The polyimide film according to claim 11, which has a yellowness index (YI) of 20 or less. The polyimide film according to claim 11, which has a coefficient of thermal expansion (CTE) of 20 ppm/°C or less at 50 to 250°C. The polyimide film according to claim 11, which has a transmittance of 83% or more at 550 nm. A lighting device comprising the polyimide film according to claim 11. A display device comprising the polyimide film according to claim 11. A display device comprising the polyimide resin according to claim 10.