KR20170100792A - Polyamic acid, Polyimide Resin, Polyimide Film and Display Device Comprising Thereof - Google Patents

Abstract

The present invention relates to a polyamic acid, a polyimide resin, a polyimide film and an image display device comprising the same, wherein the polyamic acid of the present invention is constituted by a combination of specific repeating units, comprises a unit structure derived from two or more diamine-based monomers and two or more dianhydride-based monomers. One of the two or more diamine-based monomers includes 4,4-methylenebis cyclohexylamine (DCHM) and the remaining one or more diamine-based monomers have one of an oxy group, a sulfone group and a fluoro group. Therefore, the polyamic acid, polyimide resin and polyimide film having the constitution have excellent elongation and optical isotropy.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyimide resin, a polyimide resin, a polyimide film,

More particularly, the present invention relates to a colorless transparent polyamic acid solution having excellent optical isotropy and elongation and a polyimide resin obtained from the solution, a polyimide resin obtained from the polyimide resin, polyimide resin, polyimide film, A mid-film and an image display device including the same.

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

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

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

To solve this problem, a method of polymerizing a polyimide containing an alicyclic monomer or a fluorene structure has been attempted in order to obtain a highly transparent polyimide.

 Japanese Patent Nos. 2010-1780349 and 20078/010494 disclose polyimide polymerization containing alicyclic monomers and fluorene structures, which have excellent transparency but have deteriorated thermal and mechanical properties.

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

The object of the present invention is to obtain a polyamic acid or polyimide film suitable for use as a display element material by maintaining the properties possessed by the conventional polyimide film and improving the elongation, transparency and optical isotropy.

Accordingly, it is an object of the present invention to provide a polyamic acid and a polyimide film having improved optical properties and improved elongation by improving optical isotropy among features of a polyimide resin which is colorless and transparent and used as an image display element material.

The present invention also provides a polyimide film made of the polyimide and an image display device including the same.

A preferred embodiment of the present invention to solve the above problems is a polyamic acid copolymerized with at least two diamine monomers and at least two dianhydride monomers,

One of the two or more diamine-based monomers is 4,4-methylenebiscyclohexylamine (DCHM), and the diamine-based monomer other than the 4,4-methylenebiscyclohexylamine (DCHM) And a diamine-based monomer having at least one functional group selected from the group consisting of a fluoro group and a fluoro group.

The 4,4-methylenebiscyclohexylamine (DCHM) is contained in an amount of 70 to 90 mol% based on the total amount of the diamine-based monomer.

The two or more dianhydride-based monomers include one dianhydride monomer in an amount of 80 to 100 mol% based on the total amount of the dianhydride-based monomer, and the remaining dianhydride monomers include the remaining dianhydride monomer And a polyamic acid.

The dianhydride-based monomer may be selected from the group consisting of oxydiphthalic dianhydride (ODPA), 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA), biphenyltetracarboxylic dianhydride (BPDA), and combinations thereof. The present invention also provides a polyamic acid which is characterized in that it is at least one selected from the group consisting of ruthenium (R) (BPDA) and combinations thereof.

Another preferred embodiment of the present invention is to provide a polyimide resin having a structure in which a polyamic acid according to the above embodiment is dehydrated and cyclized.

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

Another preferred embodiment of the present invention provides an image display device including the polyimide film according to the above embodiment.

The polyamic acid, the polyimide resin, and the polyimide film according to the present invention have advantages of being excellent in optical isotropy after forming a film or a film, having a colorless transparent property and being excellent in elongation, and thus being useful as a substrate or a protective layer of a flexible display.

According to one aspect of the present invention, there is provided a polyamic acid copolymerized with at least two diamine-based monomers and at least two dianhydride-based monomers, wherein one of the two or more diamine-based monomers is 4,4-methylenebiscyclohexyl Amine (DCHM), and the diamine-based monomer other than 4,4-methylenebiscyclohexylamine (DCHM) is a polyamic acid including a diamine-based monomer having at least one functional group selected from the group consisting of an oxy group, a sulfone group and a fluoro group Can be provided.

The polyamic acid according to the present invention is constituted by a combination of specific repeating units, and the unit structure of 4,4-methylenebiscyclohexylamine (DCHM) and dianhydride monomer must be included.

That is, when one of the two or more diamine monomers included in the polymerization of the polyamic acid is included in DCHM, there is an effect of inhibiting the formation of the resonance structure of? Electrons because there is an alicyclic diamine monomer structure, It is possible to obtain an excellent effect of high transmittance or isotropy.

In particular, the DCHM is preferably contained in an amount of 70 to 90 mol% based on the total amount of the diamine-based monomer. When the content of the DCHM is included as the above content, the optical isotropy property can be realized with a birefringence difference close to zero. As the content is increased, the improvement of the transmittance and the yellow index can be obtained. However, when the DCHM content is 90 mol% or more based on the total content of the diamine-based monomer, the degree of polymerization during the polyamic acid polymerization may be lowered, and the heat resistance and elongation percentage of the finally provided polyamide film are poor.

The diamine-based monomer other than DCHM in the two or more diamine-based monomers included in the polymerization of the polyamic acid may be selected from diamine-based monomers having at least one functional group selected from an oxy group, a sulfone group and a fluoro group Which has the advantage of improving heat resistance while maintaining a colorless transparent property.

Also, the dianhydride-based monomer comprises two or more dianhydride-based monomers, wherein one of the dianhydride-based monomers is contained in an amount of 70 to 90 mol% based on the total amount of the diamine-based monomer, It is preferable that the remaining amount of the dianhydride-based monomer except the one dianhydride-based monomer is contained as the balance.

When the dianhydride monomer is contained in an amount of 70 to 90 mol% based on the total content of the dianhydride monomer containing two or more kinds of the dianhydride monomers, the elongation and stiffness sufficient to be used as a flexible display substrate Heat resistance can be realized.

The dianhydride-based monomer may be selected from the group consisting of oxydiphthalic dianhydride (ODPA), 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydrate (6FDA), biphenyltetracarboxylic dianhydride (BPDA), and combinations thereof.

As mentioned above, the polyamic acid of the present invention constituted by the combination of the specific monomer repeating unit necessarily includes a polymer of 4,4-methylenebiscyclohexylamine (DCHM) and a dianhydride monomer, which is a specific alicyclic diamine monomer , And each polymer can be obtained by solution polymerization of the corresponding monomer materials in an organic solvent, and the polyamic acid solution is prepared by mixing these materials in a solution form and reacting.

The solvent (polymerization solvent) for the polymerization reaction of the dianhydride and the diamine is not particularly limited as long as it is a solvent dissolving the polyamic acid. As the known reaction solvent, there may be used, for example, m-cresol, N-methyl-2-pyrrolidone (NMP), dimethylformamide (DMF), dimethylacetamide (DMAc), dimethylsulfoxide (DMSO) One or more polar solvents are used. In addition, a low boiling point solution such as tetrahydrofuran (THF), chloroform or a low-absorbency solvent such as? -Butyrolactone may be used.

The polyamic acid can be prepared by polymerization in a nitrogen or argon atmosphere at a reaction temperature of -10 to 100 ° C and a reaction time of 2 to 48 hours at a 1: 1 equivalent ratio of the dianhydride and the diamine described above.

Although the content of the solvent is not particularly limited, the content of the solvent for polymerization (first solvent) in the polyamic acid solution is preferably 50 to 95% by weight, more preferably, More preferably 70 to 90% by weight.

Another preferred embodiment of the present invention is to provide a polyimide resin having a structure in which a polyamic acid according to the above embodiment is dehydrated and cyclized.

The polyimide resin prepared by imidizing the polyamic acid solution prepared as described above preferably has a glass transition temperature (Tg) of 200 to 320 ° C in consideration of thermal stability.

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

In the above polyimide film production method, in the step of casting and imidizing the polymerized polyamic acid on a support, the imidization method to be applied includes a thermal imidation method, a chemical imidation method, or a thermal imidation method, Can be applied in combination with other methods.

The thermal imidation method is a method in which a polyamic acid solution is cast on a support and heated for 1 to 8 hours while gradually heating the solution in a temperature range of 40 to 280 ° C to obtain a polyimide film.

In the chemical imidation method, a dehydrating agent represented by an acid anhydride such as acetic anhydride and a imidation catalyst represented by tertiary amines such as isoquinoline, β-picoline, and pyridine are added to the polyamic acid solution. When the thermal imidation method or the thermal imidization method is used in combination with the chemical imidation method, the heating conditions of the polyamic acid solution may be varied depending on the type of the polyamic acid solution, the thickness of the polyimide film to be produced, and the like.

More specifically, a polyimide film production example in which the thermal imidation method and the chemical imidization method are used in combination is described. More specifically, a polyimamic acid solution is loaded with a dehydrating agent and an imidation catalyst, cast on a support, Preferably 100 to 180 占 폚 to activate the dehydrating agent and the imidation catalyst to partially cure and dry it, and then heated at 200 to 280 占 폚 for 5 to 400 seconds to obtain a polyimide film.

In the present invention, a polyimide film may be prepared from the polyamic acid solution as follows. Namely, after the obtained polyamic acid solution is imidized, the imidized solution is put into a second solvent, followed by precipitation, filtration and drying to obtain a solid content of the polyimide resin, and the solid content of the obtained polyimide resin is added to the first solvent Can be obtained through a film-forming process using a dissolved polyimide solution.

The first solvent may be the same solvent as that used in the polymerization of the polyamic acid solution. The second solvent may be one having a lower polarity than the first solvent in order to obtain the solid content of the polyimide resin, Alcohols, ethers, and ketones. At this time, the content of the second solvent is not particularly limited, but is preferably 5 to 25% by weight based on the weight of the polyamic acid solution.

It is preferable that the polyimide resin solids obtained as described above are filtered and dried by considering the boiling point of the second solvent at a temperature of 50 to 120 ° C and a time of 3 to 24 hours. Thereafter, the polyimide solution in which the polyimide resin solids are dissolved is cast on a support and heated at a temperature in the range of 40 to 280 ° C for 1 minute to 8 hours to obtain a polyimide film.

The thickness of the polyimide film obtained by the above-described method is not particularly limited, but is preferably in the range of 10 to 100 mu m, more preferably 10 to 50 mu m.

The polyimide film according to the present invention has a birefringence of 0.005 or less on the basis of a film thickness of 10 占 퐉 and the polyimide film according to the present invention has a transmittance measured at 550 nm Is 88% or more and the yellowness is 2.0 or less, it can be used as a transparent substrate or a display protective layer of a display.

Another preferred embodiment of the present invention provides an image display device including the polyimide film according to the above embodiment.

That is, the polyimide film of the present invention is advantageously applied to a substrate for an image display device such as a flexible display, whereby a colorless transparent substrate having excellent optical characteristics, excellent optical isotropy and high elongation characteristics can be obtained.

Example

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are for the purpose of illustrating the present invention more specifically, and the present invention is not limited thereto.

≪ Example 1 >

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 325.526 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 33.658 g (0.160 mol) of DCHM, . After completion of the DCHM dissolution, 12.809 g (0.040 mol) of TFDB was added and dissolved for 1 hour. After the dissolution of DCHM and TFDB was completed, 62.042 g (0.200 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 75 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

≪ Example 2 >

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 315.932 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 33.658 g (0.160 mol) of DCHM, . After completion of the DCHM dissolution, 12.809 g (0.040 mol) of TFDB was added and dissolved for 1 hour. After dissolution of DCHM and TFDB was completed, 58.844 g (0.200 mol) of BPDA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid concentration of 25% by weight and a viscosity of 110 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

≪ Example 3 >

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 324.760 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 26.926 g (0.128 mol) of DCHM, . After DCHM dissolution was completed, 10.2479 g (0.032 mol) of TFDB was added and dissolved for 1 hour. After dissolution of DCHM and TFDB was completed, 71.080 g (0.160 mol) of 6FDA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 71 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

<Example 4>

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 332.119 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 29.450 g (0.140 mol) of DCHM, . After completion of DCHM dissolution, 19.214 g (0.060 mol) of TFDB was added and dissolved for 1 hour. After the dissolution of DCHM and TFDB was completed, 62.042 g (0.200 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜 and then reacted for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 89 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

&Lt; Example 5 >

318.934 g of dimethylacetamide (DMAc) was charged into a 500 ml reactor equipped with a stirrer, a nitrogen inlet, a dropping funnel, a temperature controller and a condenser while passing nitrogen, and 37.865 g (0.180 mol) of DCHM, . After dissolution of DCHM was completed, 6.405 g (0.020 mol) of TFDB was added and dissolved for 1 hour. After the dissolution of DCHM and TFDB was completed, 62.042 g (0.200 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜 and then reacted for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 55 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Example 6 >

In a 500 ml reactor equipped with a stirrer, a nitrogen inlet, a dropping funnel, a temperature controller and a condenser, 311.123 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 33.658 g (0.160 mol) of DCHM, . After DCHM dissolution was completed, 8.008 g (0.040 mol) of ODA was added and dissolved for 1 hour. After dissolution of DCHM and ODA was completed, 62.042 g (0.200 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid concentration of 25% by weight and a viscosity of 77 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 12 占 퐉 was prepared.

&Lt; Example 7 >

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 331.682 g of dimethylacetamide (DMAc) was charged while passing nitrogen, 37.023 g (0.176 mol) of DCHM, . After completion of the DCHM dissolution, 8.809 g (0.044 mol) of ODA was added and dissolved for 1 hour. After the dissolution of DCHM and ODA was completed, 64.728 g (0.220 mol) of BPDA was added. Thereafter, the temperature of the solution was maintained at 50 캜 and then reacted for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 52 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

&Lt; Example 8 >

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 332.815 g of dimethylacetamide (DMAc) was charged while passing nitrogen, 28.609 g (0.136 mol) of DCHM, . After dissolution of DCHM was completed, 6.807 g (0.034 mol) of ODA was added and dissolved for 1 hour. After dissolution of DCHM and ODA was completed, 75.523 g (0.17 mol) of 6FDA was added. Thereafter, the temperature of the solution was maintained at 50 캜 and then reacted for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 35 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

&Lt; Example 9 >

338.998 g of dimethylacetamide (DMAc) was charged into a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser while passing nitrogen, and 33.658 g (0.160 mol) of DCHM, . After dissolution of DCHM was completed, 17.300 g (0.040 mol) of BAPSM was added and dissolved for 1 hour. After the dissolution of DCHM and BAPSM was completed, 62.042 g (0.200 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 30 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Example 10 >

In a 500 ml reactor equipped with a stirrer, a nitrogen inlet, a dropping funnel, a temperature controller and a condenser, 329.404 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 33.658 g (0.160 mol) of DCHM, . After dissolution of DCHM was completed, 17.300 g (0.040 mol) of BAPSM was added and dissolved for 1 hour. After dissolution of DCHM and BAPSM was completed, 58.844 g (0.200 mol) of BPDA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a concentration of solid content of 25% by weight and a viscosity of 25 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Example 11 >

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 335.537 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 26.926 g (0.128 mol) of DCHM, . After dissolution of DCHM was completed, 13.840 g (0.032 mol) of BAPSM was added and dissolved for 1 hour. After dissolution of DCHM and BAPSM was completed, 71.080 g (0.160 mol) of 6FDA was added. Thereafter, the temperature of the solution was maintained at 50 캜 and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a concentration of solid content of 25% by weight and a viscosity of 32 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

&Lt; Example 12 >

In a 500 ml reactor equipped with a stirrer, a nitrogen inlet, a dropping funnel, a temperature controller and a condenser, 334.241 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 35.340 g (0.168 mol) of DCHM, . After DCHM dissolution was completed, 6.725 g (0.021 mol) of TFDB was added and dissolved for 1 hour. After TFDB dissolution was completed, 4.204 g (0.021 mol) of ODA was added and dissolved for 1 hour. After dissolution of all three diamine-based monomers was completed, 65.144 g (0.210 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 62 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Example 13 >

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 340.795 g of dimethylacetamide (DMAc) was charged while passing nitrogen, 35.340 g (0.168 mol) of DCHM, . After dissolution of DCHM was completed, 13.450 g (0.042 mol) of TFDB was added and dissolved for 1 hour. After dissolution of DCHM and TFDB was completed, 58.630 g (0.189 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 ° C., and the reaction was carried out for 12 hours. 6.179 g (0.021 mol) of BPDA

The temperature was maintained at 50 ° C and then further reacted for 12 hours.

As a result, a polyamic acid solution having a solid concentration of 25 wt% and a viscosity of 81 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

&Lt; Comparative Example 1 &

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 325.526 g of dimethylacetamide (DMAc) was charged while passing nitrogen, 42.072 g (0.200 mol) of DCHM, . After the DCHM dissolution was completed, 62.042 g (0.200 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜 and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 20 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

&Lt; Comparative Example 2 &

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 302.748 g of dimethylacetamide (DMAc) was charged while passing nitrogen, 42.072 g (0.200 mol) of DCHM, . After DCHM dissolution was complete, 58.844 g (0.200 mol) of BPDA was added. Thereafter, the temperature of the solution was maintained at 50 캜 and then reacted for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 35 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Comparative Example 3 &

Into a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 324.032 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 34.709 g (0.165 mol) of DCHM, . After the DCHM dissolution was completed, 73.301 g (0.165 mol) of 6FDA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid concentration of 25% by weight and a viscosity of 17 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Comparative Example 4 &

In a 500 ml reactor equipped with a stirrer, a nitrogen inlet, a dropping funnel, a temperature controller and a condenser, 310.773 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 18.932 g (0.090 mol) of DCHM, . After DCHM dissolution was completed, 28.821 g (0.090 mol) of TFDB was added and dissolved for 1 hour. After dissolution of DCHM and TFDB was completed, 55.838 g (0.180 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 210 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Comparative Example 5 &

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 324.759 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and then 22.088 g (0.105 mol) of DCHM, . After DCHM dissolution was completed, 21.021 g (0.105 mol) of ODA was added and dissolved for 1 hour. After dissolution of DCHM and ODA was completed, 65.144 g (0.210 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜, and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 25% by weight and a viscosity of 130 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

&Lt; Comparative Example 6 >

In a 500 ml reactor equipped with a stirrer, a nitrogen inlet, a dropping funnel, a temperature controller and a condenser, 322.134 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 17.881 g (0.085 mol) of DCHM, . After completion of DCHM dissolution, 36.762 g (0.085 mol) of BAPSM was added and dissolved for 1 hour. After dissolution of DCHM and BAPSM was completed, 52.736 g (0.170 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 50 캜 and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a concentration of solid content of 25% by weight and a viscosity of 32 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Comparative Example 7 &

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 328.967 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and then 25.618 g (0.080 mol) of TFDB, . After the TFDB dissolution was completed, 23.538 g (0.080 mol) of BPDA was added. Thereafter, the temperature of the solution was maintained at 25 캜 and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 13% by weight and a viscosity of 120 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Comparative Example 8 >

In a 500 ml reactor equipped with a stirrer, a nitrogen injector, a dropping funnel, a temperature controller and a condenser, 330.374 g of dimethylacetamide (DMAc) was charged while passing nitrogen, and 16.016 g (0.080 mol) of ODA, . After the ODA dissolution was completed, 24.817 g (0.080 mol) of ODPA was added. Thereafter, the temperature of the solution was maintained at 25 캜 and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content concentration of 11% by weight and a viscosity of 114 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 10 탆 was prepared.

&Lt; Comparative Example 9 &

329.442 g of dimethylacetamide (DMAc) was charged into a 500-ml reactor equipped with a stirrer, a nitrogen-introducing device, a dropping funnel, a temperature controller and a condenser while passing nitrogen, and 34.599 g (0.080 mol) of BAPSM Lt; / RTI &gt; After dissolution of BAPSM was completed, 23.538 g (0.080 mol) of BPDA was added. Thereafter, the temperature of the solution was maintained at 25 DEG C and the reaction was carried out for 18 hours. As a result, a polyamic acid solution having a solid content of 15% by weight and a viscosity of 78 poise was obtained. After the reaction was completed, the obtained solution was applied to a stainless steel plate, cast to 10 to 20 占 퐉, dried by hot air at 80 占 폚 for 20 minutes, at 120 占 폚 for 20 minutes and at 280 占 폚 for 10 minutes by hot air, And a polyimide film having a thickness of 11 탆 was prepared.

How to measure

The properties of the polyimide films prepared in Examples and Comparative Examples were evaluated by the following methods. The results are shown in Tables 1 and 2 below.

(1) Measurement of permeability

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

(2) Viscosity

The Brookfield viscometer (RVDV-II + P) was measured twice at 50 rpm using Scandal 6 or Scandal 7 at 25 and the mean value was determined.

(3) Yellowness (Y.I.) measurement

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

(4) Birefringence measurement

The average value was measured at 532 nm using a birefringence analyzer (Prism Coupler, Sairon SPA4000) three times each in TE (Transeverse Elictric) mode and TM (Transverse magnetic) mode. The difference between the measured TE and TM was determined and is shown in Table 2.

(5) Coefficient of thermal expansion (CTE) measurement

Using TMA (TA Instrument, Q400), linear thermal expansion coefficients were measured twice at 50 ~ 250 according to the TMA method. The size of the specimen was 4 mm × 24 mm, the load was 0.02 N, and the rate of temperature rise was 10 / min.

Since the residual stress may remain in the film through the film formation and heat treatment, the residual stress is completely removed in the first run and the second value is presented as the measured value.

(6) elongation (%) measurement

Measured according to ASTM-D882 standard using 5967 from Instron. The size of the specimen was measured as 15 mm × 30 mm, Load cell 1 KN, and Tension rate 10 mm / min.

division ingredient Mole ratio Film thickness 550 nm transmittance Y.I. Linear linear thermal expansion coefficient
(ppm /) (탆) (%) Example 1 DCHM: TFDB / ODPA 0.8: 0.2 / 1.0 10 88.87 1.38 55.42 Example 2 DCHM: TFDB / BPDA 0.8: 0.2 / 1.0 11 88.12 1.37 54.28 Example 3 DCHM: TFDB / 6FDA 0.8: 0.2 / 1.0 10 89.11 1.01 56.17 Example 4 DCHM: TFDB / ODPA 0.7: 0.3 / 1.0 11 88.76 1.62 52.18 Example 5 DCHM: TFDB / ODPA 0.9: 0.1 / 1.0 10 89.21 1.14 59.15 Example 6 DCHM: ODA / ODPA 0.8: 0.2 / 1.0 12 88.27 1.59 57.91 Example 7 DCHM: ODA / BPDA 0.8: 0.2 / 1.0 11 88.05 1.44 56.33 Example 8 DCHM: ODA / 6FDA 0.8: 0.2 / 1.0 11 88.78 1.20 58.12 Example 9 DCHM: BAPSM / ODPA 0.8: 0.2 / 1.0 10 88.24 1.57 57.37 Example 10 DCHM: BAPSM / BPDA 0.8: 0.2 / 1.0 10 88.21 1.53 56.51 Example 11 DCHM: BAPSM / 6FDA 0.8: 0.2 / 1.0 11 88.45 1.37 58.88 Example 12 DCHM: TFDB: ODA / ODPA 0.8: 0.1: 0.1 / 1.0 10 88.25 1.42 56.48 Example 13 DCHM: TFDB / ODPA: BPDA 0.8: 0.2 / 0.9: 0.1 11 88.37 1.55 55.17 Comparative Example 1 DCHM / ODPA 1.0 / 1.0 11 89.11 0.97 63.43 Comparative Example 2 DCHM / BPDA 1.0 / 1.0 10 88.97 1.14 61.77 Comparative Example 3 DCHM / 6FDA 1.0 / 1.0 10 89.25 0.88 64.11 Comparative Example 4 DCHM: TFDB / ODPA 0.5: 0.5 / 1.0 10 87.95 3.35 41.17 Comparative Example 5 DCHM: ODA / ODPA 0.5: 0.5 / 1.0 11 87.97 2.98 43.44 Comparative Example 6 DCHM: BAPSM / ODPA 0.5: 0.5 / 1.0 10 87.54 2.81 43.79 Comparative Example 7 TFDB / BPDA 1.0 / 1.0 10 87.58 6.51 20.99 Comparative Example 8 ODA / ODPA 1.0 / 1.0 10 87.10 6.17 44.15 Comparative Example 9 BAPSM / BPDA 1.0 / 1.0 11 87.08 6.40 47.37

division Prism Coupler Transverse electric (TE) mode TM (transverse magnetic) mode Birefringence Elongation Example 1 1.6223 1.619 0.0033 26.7% Example 2 1.6311 1.627 0.0041 24.5% Example 3 1.6308 1.6281 0.0027 21.0% Example 4 1.6317 1.6274 0.0043 27.3% Example 5 1.6754 1.6735 0.0019 24.3% Example 6 1.6079 1.6051 0.0028 31.1% Example 7 1.6111 1.6074 0.0037 28.7% Example 8 1.6077 1.6055 0.0022 21.5% Example 9 1.6054 1.6029 0.0025 27.4% Example 10 1.6048 1.6015 0.0033 25.2% Example 11 1.6049 1.6030 0.0019 21.1% Example 12 1.6311 1.6274 0.0037 26.9% Example 13 1.6227 1.6187 0.0040 26.5% Comparative Example 1 1.6070 1.6062 0.0008 20.7% Comparative Example 2 1.6077 1.6066 0.0011 19.2% Comparative Example 3 1.6064 1.6057 0.0007 10.1% Comparative Example 4 1.6117 1.5830 0.0287 27.5% Comparative Example 5 1.6055 1.5849 0.0206 33.7% Comparative Example 6 1.6042 1.5841 0.0201 27.2% Comparative Example 7 1.6751 1.6117 0.0634 22.1% Comparative Example 8 1.7065 1.6969 0.0096 45.1% Comparative Example 9 1.7064 1.7040 0.0024 38.5%

As shown in the above Tables 1 and 2, the polyimide films of Examples 1 to 13, when compared with Comparative Examples 1 to 3, had at least one of an oxy group, a sulfone group and a fluoro group other than DCHM It can be confirmed that the CTE value is improved to 60 ppm or less while maintaining the low birefringence difference value (hereinafter referred to as dn) and the optical characteristics as much as possible due to the effect of the diamine-based monomer. Compared with Comparative Examples 4 to 6, when the molar ratio of DCHM is 70% or less, the CTE value is greatly improved, but it can be confirmed that it is difficult to maintain the inherent low dn value.

The results of Comparative Examples 1 to 6 show that the polyamic acid which is colorless and transparent and has a low birefringence of dn 0.0005 or less having a yellow index value of 2.0 or less while maintaining high elongation and heat resistance at a molar ratio of 70 to 90% It can be seen that polyimide can be obtained.

Comparing Comparative Examples 7 to 9 with Examples 1 to 13, the advantages of the optical characteristics of the present invention can be easily confirmed. When the diamine-based monomers having one of an oxime group, a sulfone group and a fluoro group are used alone, optical properties are somewhat poor or it is difficult to maintain optical isotropy. Therefore, the diamine-based monomers having a random or If the block structure is designed, a material suitable for the transparent substrate for display can be selected.

Claims (7)

A polyamic acid copolymerized with two or more diamine-based monomers and two or more dianhydride-based monomers,
One of the two or more diamine-based monomers is 4,4-methylenebiscyclohexylamine (DCHM), and the diamine-based monomer other than the 4,4-methylenebiscyclohexylamine (DCHM) A polyamic acid comprising a diamine-based monomer having at least one functional group selected from fluoro groups.
The polyamic acid according to claim 1, wherein the 4,4-methylenebiscyclohexylamine (DCHM) is contained in an amount of 70 to 90 mol% based on the total amount of the diamine-based monomer.
The method according to claim 1, wherein the two or more dianhydride-based monomers comprise 80 to 100 mol% of one dianhydride monomer with respect to the total amount of dianhydride-based monomers, and the remainder of the dianhydride monomer &Lt; / RTI &gt; polyamic acid.
The method of claim 1, wherein the dianhydride monomer is selected from the group consisting of oxydiphthalic dianhydride (ODPA), 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropanediamine hydride (6FDA) Tetracarboxylic dianhydride (BPDA), and combinations thereof. The polyamic acid according to claim 1, wherein the polyamic acid is at least one selected from the group consisting of tetracarboxylic dianhydride (BPDA) and combinations thereof.
A polyimide resin having a structure obtained by subjecting the polyamic acid of any one of claims 1 to 4 to dehydration cyclization.
A polyimide film produced from the polyimide resin of claim 5.
An image display device comprising the polyimide film of claim 6.