KR20050118604A - Compositions for alignment layer of liquid crystal - Google Patents

Abstract

The present invention relates to a liquid crystal alignment film composition, and more particularly, a composition containing a soluble polyimide resin and a polyamic acid derivative having a low polar alkylsuccinimide side chain group, wherein the thin film prepared using the composition has a surface roughness. It is low, not only excellent printability for ITO glass, but also excellent in heat resistance and transparency, and the liquid crystal cell produced therefrom has a pretilt angle of 89 ° or more and a voltage retention of 99% or more. It is about.

Description

Composition for alignment layer of liquid crystal

The present invention relates to a liquid crystal alignment film composition, and more particularly, a composition containing a soluble polyimide resin and a polyamic acid derivative having a low polar alkylsuccinimide side chain group, wherein the thin film prepared using the composition has a surface roughness. It is low, not only excellent printability for ITO glass, but also excellent in heat resistance and transparency, and the liquid crystal cell produced therefrom has a pretilt angle of 89 ° or more and a voltage retention of 99% or more. It is about.

In general, organic polymers such as polyimide resins, polyamide resins, and polyamideimide resins have been used as alignment film materials for liquid crystal displays. Among them, polyimide resins have excellent heat resistance and chemical resistance, and are widely applied as materials for liquid crystal alignment films. However, although the polyimide resin has such excellent properties as described above, its application in applications requiring transparency due to low light transmittance in the visible region due to the formation of a charge transfer complex is required. The disadvantage is that it is very difficult. Therefore, various kinds of main chain aliphatic polyimide-based resins have been produced, and have been applied to fields requiring excellent light transmittance such as liquid crystal alignment films.

The polyimide resins for liquid crystal alignment films in which aliphatic ring groups have been introduced to the main chain have been introduced to the side chains for the expression of the pretilt angle. The representative resins are soluble polyimide resins (SPI, soluble polyimide) and polyamic acid. However, in the case of soluble polyimide resin, there is a disadvantage in that printability is not good because of poor solubility in general organic solvents, and in the case of polyamic acid alignment layer, the voltage holding ratio (VHR) decreases due to high surface polarity. There is this. In addition, control of the pretilt angle is required for application as an alignment film that can cope with various driving modes.

Accordingly, the inventors of the present invention are suitable ratios of soluble polyimide (SPI) resins and polyamic acid derivatives having a low polar alkylsuccinimide side chain group having excellent solubility in organic solvents in a state where the imidation reaction is fully performed. This invention was completed by developing the liquid crystal aligning film which has the outstanding liquid-crystal orientation from the composition mixed with the.

 Accordingly, an object of the present invention is to provide a liquid crystal alignment film composition having excellent heat resistance, transparency, surface hardness, high voltage retention, and pretilt angle.

The present invention comprises a soluble polyimide resin represented by the following formula (1) having a low polar alkylsuccinimide side chain and an aliphatic ring side chain group, and a polyamic acid derivative represented by the following formula (2) having an aliphatic ring side chain group The liquid crystal aligning film composition which consists of this is characterized.

In Chemical Formula 1 or 2,

silver , , , , , , , , , And One or two or more tetravalent groups selected from the group consisting of at least one aliphatic ring system tetravalent group selected from the structural formulas (a), (b), (c), (d) and (e);

And Are each , , , , , , , , , , And Wherein n is a natural number in the range of 1 to 30. Comprises an aromatic divalent group having an alkylsuccinimide side chain of formula (f);

L and m each represent a natural number ranging from 1 to 300.

Referring to the present invention in more detail as follows.

The liquid crystal alignment film composition according to the present invention contains a soluble polyimide resin represented by Chemical Formula 1 and a polyamic acid derivative represented by Chemical Formula 2 as essential components. The soluble polyimide resin represented by Chemical Formula 1 and the polyamic acid derivative represented by Chemical Formula 2 contained as an essential composition component in the liquid crystal alignment film composition of the present invention have a blending ratio of 1 to 99% by weight: 1 to 99% by weight. It can be adjusted arbitrarily within.

In addition, the soluble polyimide resin represented by Chemical Formula 1 contained in the liquid crystal alignment film composition according to the present invention is a novel soluble polyimide resin developed by the present inventors, and has a specific structure with a low polar alkylsuccinimide group as a side chain group. There is a structural feature having an aliphatic ring group at the same time (Korean Patent Application No. 04-43766). The soluble polyimide resin represented by Chemical Formula 1 or the polyamic acid derivative represented by Chemical Formula 2 contained in the liquid crystal alignment film composition according to the present invention may be polycondensed with aromatic tetracarboxylic acid or derivatives thereof and aromatic diamine or aromatic diisocyanate. It may have various molecular structures depending on the type of monomer used. Generally aromatic tetracarboxylic acid monomers include pyromellitic dianhydride (PMDA), benzophenone tetracarboxylic dianhydride, oxydiphthalic dianhydride, nonphthalic dianhydride (BPDA) and hexafluoroisopropylidene diphthalic dianhydride. I choose and use it. And, as the aromatic diamine monomer, generally para-phenylenediamine ( p- PDA), meta-phenylenediamine ( m- PDA), 4,4-oxydianiline (ODA), 4,4-methylenedianiline (MDA) ), 2,2-bisaminophenylhexafluoropropane (HFDA), metabisaminophenoxydiphenylsulfone ( m- BAPS), parabisaminophenoxydiphenylsulfone ( p- BAPS), 1,4-bisamino Phenoxybenzene (TPE-Q), 1,3-bisaminophenoxybenzene (TPE-R), 2,2-bisaminophenoxyphenylpropane (BAPP), 2,2-bisaminophenoxyphenylhexafulo It is selected and used from roperopan (HFBAPP).

The soluble polyimide resin represented by the general formula (1) or the polyamic acid derivative represented by the general formula (2) contained in the liquid crystal alignment film composition according to the present invention is represented by the structural formulas (a) to (e) in addition to the general aromatic monomers described above. Prepared using an aliphatic cyclic acid dianhydride monomer containing an aliphatic tetracarboxylic dianhydride as an essential component, and a diamine monomer containing an aromatic diamine substituted with an alkyl succinimide group represented by the structural formula (f) as an essential component. It is characterized by.

That is, the soluble polyimide resin represented by the general formula (1) or the polyamic acid derivative represented by the general formula (2) is an aliphatic tetracarboxylic dianhydride monomer in addition to the conventional aromatic tetracarboxylic acid monomer as an acid dianhydride monomer 1,2,3, 4-cyclobutane tetracarboxylic dianhydride [CBDA; (a)], 1,2,3,4-cyclopentane tetracarboxylic dianhydride [CPDA; (b)], 5- (2,5-dioxotetrahydrofuryl) -3-methylcyclohexane-1,2-dicarboxylic dianhydride [DOCDA; (c)], 4- (2,5-dioxotetrahydrofuryl-3-yl) -tetraline-1,2-dicarboxylic dianhydride [DOTDA; (d)], and bicyclooctene-2,3,5,6-tetracarboxylic dianhydride [BODA; (e)] one or two or more aliphatic tetracarboxylic dianhydride selected from among the essential components. At this time, the aliphatic tetracarboxylic dianhydride represented by the structural formulas (a) to (e) is used in the range of 1 to 99 mol% with respect to the total amount of the acid dianhydride monomer.

In the case of the soluble polyimide resin represented by Chemical Formula 1, an alkyl succinimide group is simultaneously bonded with an aliphatic ring group as a side chain. Thus, as a diamine monomer, the structural formula (f) It is prepared by including an aromatic diamine substituted with an alkyl succinimide group represented by the essential component as an essential component. At this time, the aromatic diamine represented by the structural formula (f) is used in the range of 1 to 99 mol% based on the total amount of the diamine monomer.

Thus, in the soluble polyimide resin represented by Formula 1, aliphatic tetracarboxylic dianhydrides represented by the structural formulas (a) to (e) are used as essential monomers as acid dianhydride monomers, thereby minimizing degradation of mechanical properties and heat resistance of the resin. In addition, it was possible to obtain an effect of improving transparency and solubility, and as the diamine monomer, an aromatic diamine substituted with an alkyl succinimide group represented by the above formula (f) was used as an essential monomer, and thus the heat resistance, light transmittance and It can improve vertical alignment and have low surface polarity. The soluble polyimide resin represented by Formula 1 prepared by condensation polymerization and imidization with the monomer composition as described above has a weight average molecular weight (Mw) in the range of 5,000 to 150,000 g / mol, intrinsic viscosity in the range of 0.1 to 1.5 dL / g, It has a glass transition temperature range of 150 to 300 ℃. In addition, the soluble polyimide resin represented by Formula 1 is aprotic polarity such as dimethylacetamide (DMAc), dimethylformamide (DMF), N -methyl-2-pyrrolidone (NMP), acetone, ethyl acetate Easily dissolved at room temperature with respect to organic solvents such as meta-cresol, including the solvent. In particular, low solubility solvents such as tetrahydrofuran (THF), chloroform and low absorption solvents such as gamma-butyrolactone exhibit high solubility of 10% by weight or more at room temperature. Moreover, high solubility is shown also about these mixed solvents.

In addition, the polyamic acid derivative represented by Chemical Formula 2 is an acid dianhydride monomer, and an aliphatic tetracarboxylic dianhydride represented by the above structural formulas (a) to (e) is used as an essential monomer to improve mechanical properties and minimize heat resistance reduction. At the same time, it was possible to prepare a polyamic acid derivative having improved printability. The polyamic acid derivative represented by Formula 2 prepared by solution polymerization with the monomer composition as described above has a weight average molecular weight (Mw) range of 10,000 to 200,000 g / mol, intrinsic viscosity range of 0.3 to 2.0 dL / g, glass transition temperature range It has the characteristic of 200-400 degreeC, imidation temperature range 200-300 degreeC. In addition, the polyamic acid derivative represented by Formula 2 is an aprotic polar solvent such as dimethylacetamide (DMAc), dimethylformamide (DMF), N -methyl-2-pyrrolidone (NMP), acetone, ethyl acetate In addition, the organic solvent such as meta-cresol has a characteristic that is easily dissolved at room temperature. In particular, low solubility solvents such as tetrahydrofuran (THF), chloroform and low absorption solvents such as gamma-butyrolactone exhibit high solubility of 10% by weight or more at room temperature. Moreover, high solubility is shown also about these mixed solvents.

The liquid crystal aligning film composition of the present invention is prepared by dissolving a soluble polyimide resin represented by Formula 1 and a polyamic acid derivative represented by Formula 2 having the characteristics of monomer composition as described above in a solvent.

In addition, the thin film prepared from the liquid crystal alignment film composition of the present invention has a low surface roughness, not only excellent printability for ITO glass, but also excellent heat resistance and transparency. In addition, the liquid crystal cell manufactured using such a composition has a pretilt angle in the range of 85.0 to 89.9 ° and a room temperature voltage retention in the range of 98.0 to 99.9%. Therefore, the composition of the present invention is useful as a liquid crystal alignment film and a composition for producing a liquid crystal cell because of excellent electro-optical properties.

Such a present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Monomer Preparation Example 1 Synthesis of 1- (3,5-Diaminophenyl) -3-hexyl-succinicimide (DA-IM-6)

While slowly passing nitrogen gas through a 250 mL reactor equipped with a stirrer and a nitrogen injector, 9.2 g (0.05 mole) of 3,5-dinitroaniline was dissolved in 50 mL of acetic acid as a reaction solvent, and then passed through nitrogen gas. 9.1 g (0.05 mole) of 2-hexen-1-yl succinic anhydride was added and refluxed for 24 h. After the reaction solution was cooled to room temperature, a precipitated solid was obtained. The obtained solid was recrystallized in methanol to prepare 12.7 g of 1- (3,5-dinitrofenyl) -3- (1-hexene) -succinicimide (DN-IM-6) (yield 73%) ).

After dissolving 6.9 g (0.02 mole) of DN-IM-6 in 100 mL of NMP and ethanol (1/3 volume ratio), Pd / C (5%) catalyst (metal palladium on the surface of the carbon particles in an amount of 5%) After applying to the hydrogen reactor with 0.5 g), the reduction reaction was carried out at 60 ℃ for 2 hours. After filtering the reaction mixture, the reaction solvent was distilled under reduced pressure. Recrystallization in hexane / ethyl acetate cosolvent gave 3.18 g of 1- (3,5-diaminophenyl) -3-hexyl-succinicimide (DA-IM-6) (yield 55%).

Monomer Preparation Example 2 Synthesis of 1- (3,5-Diaminophenyl) -3-oxyl-succinicimide (DA-IM-8)

The reaction was carried out in the same manner as in Monomer Preparation Example 1, except that 10.5 g (0.05 mole) of 2-octen-1-yl succinic anhydride was used instead of 2-hexen-1-yl succinic anhydride. 5-Dinitrofenyl) -3- (1-octene) -succinimide (DN-IM-8) was obtained. The obtained solid was recrystallized in methanol to prepare 13.1 g of 1- (3,5-dinitrofenyl) -3- (1-octene) -succinicimide (DN-IM-8) (yield 70%). It was.

1- (3,5-diaminophenyl) -3-oxyl was prepared in the same manner as in Monomer Preparation Example 1, except that 7.5 g (0.02 mole) of DN-IM-8 was used instead of DN-IM-6. -Succinicimide (DA-IM-8) was obtained. Recrystallization in hexane / ethyl acetate cosolvent gave 3.68 g of 1- (3,5-diaminophenyl) -3-oxyl-succinicimide (DA-IM-8) (yield 58%).

Monomer Preparation Example 3 Synthesis of 1- (3,5-Diaminophenyl) -3-decyl-succinicimide (DA-IM-10)

The reaction was carried out in the same manner as in Monomer Preparation Example 1, except that 11.9 g (0.05 mole) of 2-decen-1-yl succinic anhydride was used instead of 2-hexen-1-yl succinic anhydride. 5-Dinitrofenyl) -3- (1-decene) -succinimide (DN-IM-10) was obtained. The obtained solid was recrystallized in methanol to prepare 14.5 g of 1- (3,5-dinitrofenyl) -3- (1-decene) -succinicimide (DN-IM-10) (yield 70%). It was.

1- (3,5-diaminophenyl) -3-decyl was carried out in the same manner as in Monomer Preparation Example 1, except that 8.1 g (0.02 mole) of DN-IM-10 was used instead of DN-IM-6. -Succinicimide (DA-IM-10) was obtained. Recrystallization in hexane / ethyl acetate cosolvent yielded 4.15 g of 1- (3,5-diaminophenyl) -3-decyl-succinicimide (DA-IM-10) (yield 60%).

Monomer Preparation Example 4 Synthesis of 1- (3,5-Diaminophenyl) -3-dodecyl-succinicimide (DA-IM-12)

The reaction was carried out in the same manner as in Monomer Preparation Example 1, except that 13.3 g (0.05 mole) of 2-dodecen-1-yl succinic anhydride was used instead of 2-hexen-1-yl succinic anhydride. , 5-dinitrofenyl) -3- (1-dodecene) -succinicimide (DN-IM-12) was obtained. The obtained solid was recrystallized in methanol to give 14.0 g of 1- (3,5-dinitrofenyl) -3- (1-dodecene) -succinicimide (DN-IM-12) (yield 65%). Prepared.

1- (3,5-diaminophenyl) -3-dode was carried out in the same manner as in Monomer Preparation Example 1, except that 8.6 g (0.02 mole) of DN-IM-12 was used instead of DN-IM-6. Sil-succinicimide (DA-IM-12) was obtained. Recrystallization in hexane / ethyl acetate cosolvent yielded 4.48 g of 1- (3,5-diaminophenyl) -3-dodecyl-succinicimide (DA-IM-12) (yield 60%).

Monomer Preparation Example 5 Synthesis of 1- (3,5-Diaminophenyl) -3-tetradecyl-succinimide (DA-IM-14)

Except for using 14.7 g (0.05 mole) of 2-tetradecen-1-yl succinic anhydride instead of 2-hexen-1-yl succinic anhydride was carried out in the same manner as in Monomer Preparation Example 1 1- (3,5 -Dinitrofenyl) -3- (1-tetradecene) -succinimide (DN-IM-14) was obtained. The obtained solid was recrystallized in methanol to give 14.9 g of 1- (3,5-dinitrofenyl) -3- (1-tetradecene) -succinicimide (DN-IM-14) (yield 65%). Prepared.

1- (3,5-diaminophenyl) -3-tetra was carried out in the same manner as in Monomer Preparation Example 1, except that 9.2 g (0.02 mole) of DN-IM-14 was used instead of DN-IM-6. Decyl-succinicimide (DA-IM-14) was obtained. Recrystallization in hexane / ethyl acetate cosolvent gave 5.6 g of 1- (3,5-diaminophenyl) -3-tetradecyl-succinicimide (DA-IM-14) (yield 70%).

Monomer Preparation Example 6 Synthesis of 1- (3,5-Diaminophenyl) -3-hexadecyl-succinicimide (DA-IM-16)

Except for using 16.1 g (0.05 mole) of 2-hexadecen-1-yl succinic anhydride instead of 2-hexen-1-yl succinic anhydride was carried out in the same manner as in Monomer Preparation Example 1 1- (3,5 -Dinitrofenyl) -3- (1-hexadecene) -succinimide (DN-IM-16) was obtained. The obtained solid was recrystallized in methanol to give 15.4 g of 1- (3,5-dinitrofenyl) -3- (1-hexadecene) -succinicimide (DN-IM-16) (yield 63%). Prepared.

Except for using 9.8 g (0.02 mole) DN-IM-16 instead of DN-IM-6 in the same manner as in Monomer Preparation Example 1 1- (3,5-diaminophenyl) -3-hexa Decyl-succinicimide (DA-IM-16) was obtained. Recrystallization in hexane / ethyl acetate cosolvent yielded 6.01 g of 1- (3,5-diaminophenyl) -3-oxyl-succinicimide (DA-IM-16) (yield 70%).

Monomer Preparation Example 7: Synthesis of 1- (3,5-diaminophenyl) -3-octadecyl-succinicimide (DA-IM-18)

Except for using 17.5 g (0.05 mole) of 2-octadecen-1-yl succinic anhydride instead of 2-hexen-1-yl succinic anhydride was carried out in the same manner as in Monomer Preparation Example 1 1- (3,5 -Dinitrofenyl) -3- (1-octadecene) -succinicimide (DN-IM-18) was obtained. The obtained solid was recrystallized in methanol to give 16.2 g of 1- (3,5-dinitrofenyl) -3- (1-octadecene) -succinicimide (DN-IM-18) (yield 63%). Prepared.

1- (3,5-diaminophenyl) -3-octa was prepared in the same manner as in Monomer Preparation Example 1, except that 10.3 g (0.02 mole) of DN-IM-18 was used instead of DN-IM-6. Decyl-succinimide (DA-IM-18) was obtained. 6.87 g of 1- (3,5-diaminophenyl) -3-octadecyl-succinimide (DA-IM-18) (yield 75%) was prepared by recrystallization in a hexane / ethyl acetate cosolvent. The ¹ H-NMR spectrum of 1- (3,5-diaminophenyl) -3-octadecyl-succinicimide (DA-IM-18) prepared by the above method is shown in FIG. 1.

The diamine monomer having the succinimide side chain substituted with the low polar alkyl group prepared in the monomer preparation examples 1 to 7 was able to confirm that the yield after recrystallization can be produced in 50% or more, and excellent storage stability in air Indicated.

Resin Preparation Example 1.Preparation of Polyamic Acid (CPAA-1)

Methylene dianiline (MDA; 19.8 g, 0.1 mole) was dissolved in reaction solvent N-methyl-2-pyrrolidone while slowly passing nitrogen gas through a 500 mL reactor equipped with a stirrer and a nitrogen injector, followed by nitrogen gas. The solid 1,2,3,4-cyclobutanetetracarboxylic anhydride (CBDA; 0.1 mole) was slowly added while passing through. At this time, the solid content (solid content) was fixed to 15% by weight, and stirred for 36 hours while maintaining the reaction temperature below 0 ℃ to obtain a polyamic acid solution (CPAA). ¹ H-NMR spectrum of the polyamic acid solution (CPAA) prepared by the above method is shown in FIG. 2.

The polyamic acid derivative (CPAA) was prepared in the same manner as in Resin Preparation Example 1 with the monomer composition shown in Table 1 below. The monomer composition of the prepared polyamic acid derivative is shown in Table 1 below.

Polyamic acid Monomer composition (molar ratio) Intrinsic Viscosity (g / dL) Weight average molecular weight (g / mol) Glass transition temperature (℃) Acid dianhydride Diamine CPAA-1 CBDA (1.0) MDA (1.0) 1.54 121,000 258 CPAA-2 CPDA (1.0) MDA (1.0) 0.97 112,000 255 CPAA-3 DOCDA (1.0) MDA (1.0) 0.95 95,000 301 CPAA-4 DOTDA (1.0) MDA (1.0) 0.93 92,000 312 CPAA-5 BODA (1.0) MDA (1.0) 1.05 105,000 278

Resin Preparation Example 2 Preparation of Soluble Polyimide Resin (SPI-1)

1- (3,5-diaminophenyl) -3-octadecyl-succinicimide (DA-IM) while slowly passing nitrogen gas into a 250 mL reactor equipped with a stirrer, thermostat, nitrogen injector and cooler -18) 9.15 g (0.02 mole) was dissolved in the reaction solvent N-methyl-2-pyrrolidone, and then passed through nitrogen gas to solid dioxotetrahydrofuryl-3-methylcyclohexane-1,2-dica. 5.28 g (0.02 mole) of dianhydride was slowly added. At this time, the solid content (solid content) was fixed to 20% by weight, and stirred for 24 hours while maintaining the reaction temperature below 0 ℃ to obtain a polyamic acid solution. 6.12 g (0.06 mole) of acetic anhydride and 0.1 g (0.1 mole) of pyridine were added to the polyamic acid solution. The mixture was stirred at room temperature for 24 hours, stirred at 120 ° C. for 3 hours, and then washed several times in methanol to obtain a soluble polyimide resin. (SPI-1) was obtained. ¹ H-NMR spectrum of the soluble polyimide resin (SPI-1) prepared by the above method is shown in FIG. 3.

To the polyimide resin (SPI) was prepared in the same manner as in the resin preparation example 2 in the monomer composition as shown in Table 2. The monomer composition, intrinsic viscosity, weight average molecular weight, and glass transition temperature of the prepared polyamide resin are shown in Table 2 below.

Polyimide resin Monomer composition (molar ratio) Intrinsic Viscosity (g / dL) Weight average molecular weight (g / mol) Glass transition temperature (℃) Acid dianhydride Diamine SPI-1 DOCDA (1.0) DA-IM-18 (1.0) 0.57 45,000 187 SPI-2 DOCDA (1.0) DA-IM-16 (1.0) 0.63 54,000 205 SPI-3 DOCDA (1.0) DA-IM-14 (1.0) 0.65 60,000 225 SPI-4 DOCDA (1.0) DA-IM-12 (1.0) 0.65 62,000 245 SPI-5 DOCDA (1.0) DA-IM-10 (1.0) 0.69 70,000 247 SPI-6 DOCDA (1.0) DA-IM-8 (1.0) 0.78 76,000 250 SPI-7 DOCDA (1.0) DA-IM-6 (1.0) 0.87 89,000 255

Examples 1-7 and Comparative Examples 1-2: Preparation of Liquid Crystal Alignment Film Composition

80 g of N-methyl-2-pyrrolidone, 120 g of gamma -butylolactone, and 60 g of 2-n-butoxyethanol, while slowly passing nitrogen gas through a 1000 mL reactor equipped with a stirrer and a nitrogen injector. To the mixed solution, a polyamic acid and a soluble polyimide resin were each added in an amount range as shown in Table 3 below, followed by stirring for 24 hours to prepare a composition. Intrinsic viscosity of the prepared composition was measured and shown in Table 3 below.

Experimental Example 1 Measurement of Properties of Thin Films

The compositions prepared according to Examples 1 to 7 and Comparative Examples 1 to 2 were spin coated on a ITO glass plate at a thickness of 0.05 to 0.2 μm, and then thermally cured at a temperature of 230 ° C. for 30 minutes to prepare a thin film. The physical properties of the prepared thin film are shown in Table 3 below.

division Composition water Thin film properties Composition (% by weight) Intrinsic viscosity ^*) (dL / g) MDT (℃) RW (%) Surface tension (dyne / cm) Pencil hardness Polyimide Polyamic acid Example 1 (BPAA-1) SPI-1 (2) CPAA-1 (98) 0.98  492 43 39.5 H Example 2 (BPAA-2) SPI-1 (5) CPAA-1 (95) 0.95  488 37 36.2 2H Example 3 (BPAA-3) SPI-1 (10) CPAA-1 (90) 0.91  484 34 36.1 2H Example 4 (BPAA-4) SPI-1 (30) CPAA-1 (70) 0.72  476 29 35.5 2H Example 5 (BPAA-5) SPI-1 (50) CPAA-1 (50) 0.54  476 25 35.2 2H Example 6 (BPAA-6) SPI-1 (70) CPAA-1 (30) 0.82  476 23 35.2 2H Example 7 (BPAA-7) SPI-1 (90) CPAA-1 (10) 0.64 472 20 35.0 2H Comparative Example 1 (SPI) SPI-1 (100) - 0.11  492 14 35.4 B Comparative Example 2 (CPAA) - CPAA-1 (100) 1.00  496 44 44.6 B ^*) Measured at 30 ° C. at a concentration of 0.5 g / dL using N-methyl-2-pyrrolidone (NMP) as a solvent.

As shown in Table 3, the intrinsic viscosity of the composition containing the soluble polyimide resin alone (Comparative Example 1) was 0.11 dL / g, the intrinsic viscosity of the composition containing the polyamic acid alone (Comparative Example 2) is 1.0 dL / g, and the resins of Comparative Examples 1 and 2 were excellent in film forming and mechanical properties by solvent casting.

On the contrary, according to the present invention, the composition containing the soluble polyimide resin and the polyamic acid derivative having the alkyl succinimide side chain group introduced therein can be found to have an intrinsic viscosity in the range of 0.5 to 0.98. It can be seen that it has a molecular weight that can represent. In addition, thin films prepared using such compositions showed a tendency to decrease with increasing content of diamine in which alkylsuccinimide side chain groups were introduced in surface tension, and had a surface tension range of 35 to 40 dyne / cm. It can be seen that. The composition of the present invention has a pencil hardness of about H to 2H, it can be seen that the surface hardness is significantly improved compared to the thin film (CPAA, Comparative Example 2) containing a polyamic acid alone component.

Experimental Example 2 Measurement of Characteristics of Liquid Crystal Cell

The compositions prepared according to Examples 1 to 7 and Comparative Examples 1 to 2 maintain a solution viscosity at room temperature of 20 to 40 cps, and then a thin film coating (coating condition; 400 to 4,000 rpm, 25 seconds) to form a liquid crystal cell. Was produced. The characteristics of the produced liquid crystal cell are shown in Table 4 below. The alignment state of the liquid crystal was visually observed using a polarizing microscope, and the pretilt angles of the liquid crystal cells were measured using a crystal rotation method.

division Pretilt angle (°) VHR (%) (room temperature) RDC (mV) Example 1 (BPAA-1) 90 99 300 Example 2 (BPAA-2) 90 99 260 Example 3 (BPAA-3) 90 98 250 Example 4 (BPAA-4) 90 99 255 Example 5 (BPAA-5) 90 99 245 Example 6 (BPAA-6) 90 99 240 Example 7 (BPAA-7) 90 99 220 Comparative Example 1 (SPI) 5.0 97 660 Comparative Example 2 (CPAA) 89.9 99 200

As shown in Table 4, the liquid crystal cell produced using the composition according to the present invention showed a very high pretilt angle and voltage retention, it can be seen that the excellent residual voltage characteristics. That is, compared with the case of using the composition containing polyamic acid alone (Comparative Example 2), the pretilt angle was increased more than about 90 °, the voltage retention at room temperature was more than 98% to increase the result. In addition, the residual voltage of the liquid crystal cell using the composition containing the polyamic acid alone (Comparative Example 2) was 660 mV, but by using a soluble polyimide resin, the residual voltage was reduced to 220 mV. Therefore, it was confirmed that the composition of the present invention exhibited properties suitable for use as a liquid crystal alignment film for vertical alignment TFT-TN and STN LCD.

As described above, the present invention is characterized by a composition containing a soluble polyimide resin having a low polar alkylsuccinimide side chain and an aliphatic ring side chain group and a polyamic acid having an aliphatic ring side chain group. Such a composition of the present invention has not only excellent light transmittance, heat resistance and mechanical properties, but also has a novel structure of a vertically aligned liquid crystal alignment film having excellent electro-optical properties and high pretilt angles, and these require TFTs requiring difficult electro-optic properties. It has been found to be useful as a liquid crystal alignment film for TN and STN LCDs and various advanced heat-resistant structural materials.

In the present invention described above in detail only for the embodiments described, it will be apparent to those skilled in the art that various modifications and changes are possible within the technical spirit of the present invention, and such modifications and modifications belong to the appended claims.

1 is a ¹ H-NMR spectrum of a 1- (3,5-diaminophenyl) -3-octadecyl-succinimide (DA-IM-18) monomer.

2 is a ¹ H-NMR spectrum of the polyamic acid (CPAA) prepared in Resin Synthesis Example 1. FIG.

3 is a ¹ H-NMR spectrum of a soluble polyimide resin (SPI) prepared in Resin Synthesis Example 2. FIG.

4 is a TGA curve for the liquid crystal alignment film compositions (BPAA-1 to BPAA-4) prepared in Examples 1 to 4;

5 is a UV spectrum of the liquid crystal alignment film compositions (BPAA-1 to BPAA-4) prepared in Examples 1 to 4.

Claims (9)

Characterized in that it contains a soluble polyimide resin represented by the following formula (1) having a low polar alkylsuccinimide side chain and an aliphatic ring backbone group, and a polyamic acid derivative represented by the following formula (2) having an aliphatic ring backbone group Liquid crystal aligning film composition: [Formula 1] [Formula 2] In Chemical Formula 1 or 2, silver , , , , , , , , , And One or two or more tetravalent groups selected from the group consisting of at least one aliphatic ring system tetravalent group selected from the structural formulas (a), (b), (c), (d) and (e); And Are each , , , , , , , , , , And Wherein n is a natural number in the range of 1 to 30. Comprises an aromatic divalent group having an alkylsuccinimide side chain of formula (f); L and m each represent a natural number ranging from 1 to 300. The liquid crystal alignment film composition of claim 1, wherein 1 to 99% by weight of the soluble polyimide resin represented by Formula 1 and 1 to 99% by weight of the polyamic acid derivative represented by Formula 2 are contained. The intrinsic viscosity of the soluble polyimide resin represented by Chemical Formula 1 is in the range of 0.1 to 1.5 dL / g, the weight average molecular weight is in the range of 5,000 to 150,000 g / mol, and the glass transition temperature is 150 to 300. It is C, The liquid crystal aligning film composition characterized by the above-mentioned. The intrinsic viscosity of the polyamic acid derivative represented by Chemical Formula 2 is in the range of 0.3 to 2.0 dL / g, the weight average molecular weight is in the range of 10,000 to 200,000 g / mol, and the glass transition temperature is 200 to 400 ° C. The liquid crystal aligning film composition characterized by the above-mentioned. The imidation temperature range of the polyamic acid derivative represented by said Formula (2) is 200-300 degreeC, The liquid crystal aligning film composition of Claim 1 or 4 characterized by the above-mentioned. The soluble polyimide resin represented by Formula 1 and the polyamic acid derivative represented by Formula 2 include dimethylacetamide, dimethylformamide, N -methyl-2-pyrrolidone, tetrahydrofuran and chloroform. , Acetone, ethyl acetate and gamma-butyrolactone liquid crystal aligning film composition, characterized in that it has a dissolution property for a solvent selected from. Liquid crystal alignment film characterized in that the coating composition prepared by claim 1. Liquid crystal cell, characterized in that prepared by thin film coating the composition of claim 1. The liquid crystal cell of claim 8, wherein the liquid crystal cell has a pretilt angle in a range of 89.5 to 90.0 ° and a room temperature voltage retention of 98.0 to 99.9%.