KR20080109686A - Low temperature processable substituted alicyclic polyimide photo-alignment layers and method for preparing liquid crystal cells - Google Patents

Abstract

A low temperature processable substituted alicyclic polymide photo-alignment layer is provided to offer a photo-alignment layer which is produced using a polymide resin which has an excellent heat resistance, a surface hardness, and a transparency. A low-temperature processable aliphatic ring system soluble polyamide resin is dissolved at the organic solvent in the room temperature. The dissolved polyimide resin is coated on the ITO(Indium-Tin Oxide) glass plate. A polarized light ultraviolet ray is irradiated after drying the coated polyimide resin.

Description

Low temperature processable substituted alicyclic polyimide photo-alignment layers and method for preparing liquid crystal cells}

1 is a ¹ H NMR spectrum of DM-SPI-1 prepared according to Example 5 of the present invention.

2 is a DSC spectrum of DM-SPI-1 prepared according to Example 5 of the present invention.

3 is a ¹ H NMR spectrum of DM-CBDA prepared according to Preparation Example 1 of the present invention.

4 is a ¹ H NMR spectrum of DP-CBDA prepared according to Preparation Example 4 of the present invention.

The present invention relates to a method for producing an aliphatic ring type high hardness low temperature process type soluble polyimide photoalignment membrane, and more particularly, an aromatic containing an acid dianhydride and an aromatic diamine containing an aliphatic ring acid dianhydride in an appropriate ratio or more. A novel soluble polyimide prepared by solution polymerization of diamines, an optical alignment film prepared therefrom, and a liquid crystal cell prepared using the optical alignment film and a method for producing the optical alignment film, wherein the novel soluble polyimide has a low temperature processability. Excellent heat resistance, surface hardness, transparency, and polarized ultraviolet rays.

In addition, the thin film made of the novel soluble polyimides for the liquid crystal alignment film of the present invention has a low surface roughness, not only excellent printability for ITO glass, but also excellent heat resistance and transparency. The liquid crystal cell is characterized by providing a low pretilt angle in the range of 0.1 to 1.0 ° and excellent voltage retention of at least 98% at room temperature.

In general, the polyimide resin refers to a high heat resistant resin prepared by condensation polymerization of an aromatic tetracarboxylic acid or a derivative thereof with an aromatic diamine or an aromatic diisocyanate, followed by imidization.

The polyimide resin may have various molecular structures according to the type of monomer used, and in general, an aromatic tetracarboxylic acid component uses pyromellitic dianhydride (PMDA) or nonphthalic anhydride (BPDA). Examples of the aromatic diamine components include 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-bisaminophenoxybenzene ( TPE-Q), 1,3-bisaminophenoxybenzene (TPE-R), 2,2-bisaminophenoxyphenylpropane (BAPP), 2,2-bisaminophenoxyphenylhexafuluropropane ( It is produced by polycondensation polymerization using aromatic diamine such as HFBAPP). Most polyimide resins are insoluble and insoluble ultra-high temperature resistant resins, which are characterized by (1) excellent thermal oxidation resistance, (2) high usable temperature, and (3) long-term temperature of about 260 ° C and short-term temperature of about 480 ° C. It has excellent heat resistance, (4) radiation resistance, (5) excellent low temperature property, and (6) excellent chemical resistance.

However, although polyimide resins have the characteristics described above, they are difficult to be applied to fields requiring transparency due to low light transmittance in the visible region due to the formation of charge transfer complexes. There are disadvantages.

In addition, polyamine-based resins for liquid crystal alignment films in which aliphatic ring groups have been introduced to the main chain have been mainly used, but diamines containing aromatic rings are mainly used. However, in most cases, they have high polarizability due to the high polarizability of aromatic diamines. There is a disadvantage in that electrical characteristics such as voltage holding ratio) are lowered.

Moreover, polyimide resins for liquid crystal alignment films used to date have a disadvantage in that they are difficult to use in plastic substrates used for flexible liquid crystal display devices due to high process temperatures.

Accordingly, the present invention provides a high hardness low temperature process type soluble polyimide and a method for producing the same that can solve the above problems.

In another aspect, the present invention is to provide an optical alignment film made of the soluble polyimide and a method of manufacturing the same.

The present invention also provides a novel polyimide resin having low temperature processability, excellent heat resistance, surface hardness, transparency, and polarization ultraviolet ray alignment, and a photoalignment film made of the resin.

The present invention also provides a liquid crystal cell prepared from the liquid crystal alignment film using the soluble polyimide.

More specifically, the present invention is a thin film made of a soluble polyimide prepared for the liquid crystal alignment film has a low surface roughness, excellent printability to conductive glass (ITO glass) as well as excellent heat resistance and transparency, The fabricated liquid crystal cell provides a soluble polyimide liquid crystal alignment film having a characteristic of providing a low pretilt angle in the range of 0.1 to 1.0 ° and excellent voltage retention of 98% or more at room temperature.

In another aspect, the present invention is to provide a novel photodegradable liquid crystal alignment film by irradiating polarized ultraviolet rays to a soluble polyimide thin film having high transparency in the heat resistance and visible light region, low process temperature and excellent voltage retention, It is also to provide a liquid crystal cell having a low pretilt angle.

As a result of many studies to solve the above problems, the present inventors prepared a soluble polyimide by reacting an acidic anhydride having an aliphatic ring structure with a substituent with an aromatic diamine, and obtained a soluble polyimide thin film using the same. The present invention has been completed by developing a novel optical alignment film having excellent liquid crystal orientation, excellent voltage holding ratio (VHR) and a low line inclination angle in the range of 0.1 to 1.0 ^o by irradiating polarized ultraviolet rays to the light.

That is, in the present invention, as an acid dianhydride having an aliphatic ring structure having a substituent, 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (DM-CBDA), 1,3-diethyl -1,2,3,4-cyclobutanetetracarboxylic dianhydride (DE-CBDA), 1,3-dipropyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (DP-CBDA), Any one or more acid anhydrides selected from acid dianhydrides having aliphatic ring structures having substituents such as 1,3-diphenyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (DPh-CBDA), 1 , 4-diaminobenzene, 1,3-diaminobenzene, 4,4'-diamino-3,3'-dimethyl-diphenylmethane, 4,4'-oxydianiline, 4,4'-methylenedi Aniline, 4,4 '-(perfluoropropane-2,2'-diyl) dianiline, 4,4'-(1,3-phenylenebis (oxy)) dianiline, 4,4 '-(1 , 4-phenylenebis (oxy)) dianiline, 4-amino-N- (4-aminophenyl) benzamide, 4,4 '-(4,4'-sulfonylbis (4,1-phenylene) ratio (Oxy)) dianiline, 4,4 '-(4,4'-(perfluoropropane-2,2-diyll) bis (4,1-phenylene)) bis (oxy) dianiline, 4, Soluble polys are polymerized by polymerizing with aromatic diamines selected from 4 '-(4,4'-(propane-2,2-diyl) bis (4,1-phenylene)) bis (oxy) dianiline or the like or mixtures thereof. The mead was obtained and the present invention was completed.

Soluble polyimide prepared from acid dianhydride and aromatic diamine having an aliphatic ring structure having the above substituents has a low temperature processability and excellent ability to be easily applied at low temperature by irradiating polarized ultraviolet rays after thinning through known means. The invention has been unexpectedly completed by developing a novel liquid crystal photoalignment film having heat resistance, transparency, high surface hardness, voltage retention and low pretilt angle.

Hereinafter, the present invention will be described in more detail.

The present invention provides an aliphatic ring-based soluble polyimide resin for a low temperature process represented by the following formula (1).

M in Formula 1 is a natural number in the range of 1 to 500;

R ₁ to R ₄ are each independently hydrogen, C ₁ ~ C ₃₀ linear or branched saturated or unsaturated alkyl group, C ₆ ~ C ₁₂ aryl group, C ₁ ~ C ₃₀ alkoxy substituted C ₆ ~ C ₃₀ is an aryl group or a C ₆ ~ C ₃₀ heteroaryl group, all of the aryl groups may be substituted with a linear or branched saturated or unsaturated alkyl group, ester group, carbonyl group, halogen or amino group of C ₁ ~ C ₃₀ And;

은

silver

It includes at least one aromatic divalent group selected from.

은 하기 식1-1 ~ 식1-12의 방향족 디아민으로부터 유도되는 2가 기이다.remind

Is a divalent group derived from the aromatic diamine of the following formulas 1-1 to 1-12.

In addition, the present invention is an acid dianhydride mixture comprising an acid dianhydride having an aliphatic ring structure having any one or more substituents selected from R ₁ to R ₄ of the formula (2) and any one selected from formulas ₁ to ₁ to 12 It is also within the scope of the present invention to polymerize and prepare aromatic diamine mixtures comprising aromatic diamines of one idea. In this case, the following Chemical Formula 2 is used in the total acid dianhydride 1 ~ 100 mol%, any one or more aromatic diamines selected from the above formulas 1 to 1 to 12 can also be used properly selected from the range of 1 to 100 mol%. .

(Wherein R ₁ to R ₄ are the same as defined in Chemical Formula 1).

In the present invention, the soluble polyimide resin represented by Formula 1 or a copolymer thereof is a soluble polyimide prepared from an acid dianhydride and an aromatic diamine having an aliphatic ring structure having a substituent as a novel substance, and has low temperature processability, heat resistance and mechanical properties. In addition, the liquid crystal cell made of the above-mentioned soluble polyimide has the effect that the pretilt angle and the electro-optical characteristic are particularly remarkably improved.

The soluble polyimide resin of the present invention has a weight average molecular weight (Mw) of 10,000 to 500,000 g / mol, an intrinsic viscosity range of 0.3 to 2.0 dL / g, and a glass transition temperature range of 200 to 400 ° C.

In addition, the soluble polyimide resin according to the present invention has room temperature for an aprotic polar solvent and organic solvent such as dimethylacetamide (DMAc), dimethylformamide (DMF) and N -methyl-2-pyrrolidone (NMP). Easily soluble in In particular, it exhibits a high solubility of 10% by weight or more even at low temperatures for low-absorbent solvents such as gamma-butyrolactone, and high solubility for mixed solvents of the above solvents.

The present invention can obtain the desired physical properties of the present invention even in the case of a mixture of soluble polyimide resins having the above physical properties.

The soluble polyimide resin according to the present invention exhibits excellent low temperature processability, better mechanical strength, heat resistance, liquid crystal alignment characteristics, etc., while maintaining the excellent properties of the existing polyamic acid type polyimide resin. It can be used as a core heat-resistant material for high-tech industries.

In addition, the polyimide thin film prepared by the soluble polyimide resin of the present invention can be prepared by the irradiation of polarized ultraviolet rays of 100 to 2,000 mJ / cm ² intensity at a wavelength of 220 ~ 460 nm, to prepare a photo-alignment film, the prepared photo-alignment film As a result of evaluating the electro-optical characteristics, the liquid crystal cell manufactured using the liquid crystal cell had a pretilt angle in the range of 0.1 to 1 °, and a voltage retention at 25 ° C. and 3V voltage in the range of 98.0 to 99.5%. At this time, the liquid crystal was used Merck E-7.

Hereinafter, the present invention will be described in more detail with reference to Preparation Examples and Examples, but the present invention is not limited thereto.

Having a substituent of the formula (2) Aliphatic ring  Structured Acid dianhydride  Produce

Preparation Example 1. Preparation of 1,3-dimethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (DM-CBDA).

A stirrer and a cooler were installed in a 2L quartz glass photoreactor equipped with 16 300 nm UV lamps, and 250 ml of ethyl acetate and 100 g of citraconic anhydride were added to the quartz glass reactor, and the mixture was stirred well. In order to prevent the temperature from rising too high due to the ultraviolet lamp, the air-cooled cooler was started first, and then the ultraviolet lamp was turned on and photoreacted while stirring well to prevent the reactants from sticking to the reactor wall for 150 hours to obtain 40 g of a white solid.

The white solid obtained was filtered off and dried for 24 hours at 60 DEG C under reduced pressure. The dried solid was added to anhydrous acetic anhydride and slowly heated to 150 ° C. while melting to react for 24 hours. The reaction solution was filtered through a filter paper in a hot state and then recrystallized in a refrigerator at 0 ° C. or lower for 24 hours to obtain a yellow solid. The obtained solid was filtered and washed three times with 1,4-dioxin to remove acetic anhydride, and then dried in a vacuum oven at 60 ° C. for 48 hours to give a pale yellow 1,3-dimethyl-1,2,3,4-cyclo 35 g of butanetetracarboxylic dianhydride (DM-CBDA) was obtained. ¹ H-NMR spectrum of the material is shown in FIG.

Preparation Example 2. Preparation of 1,3-diethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (DE-CBDA).

Prepared in the same manner as in Preparation Example 1 1-3-diethyl-1,2,3,4 by photoreaction of an ultraviolet lamp for 200 hours using 3-Ethyl-2,5-furandione instead of citraconic anhydride -27 g of cyclobutanetetracarboxylic dianhydride (DE-CBDA) was obtained, and the product was confirmed by ¹ H-NMR as in Preparation Example 1.

Preparation Example 3. Preparation of 1,3-dipropyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (DPR-CBDA)

1,3-dipropyl-1, in the same manner as in Preparation Example 1, except that by using a 3-propyl-2,5-furandione instead of the light-reacting ultraviolet lamp for 180 hours using 1-3-dipropyl-1, 24 g of 2,3,4-cyclobutanetetracarboxylic dianhydride (DPR-CBDA) was obtained, and the product was confirmed by ¹ H-NMR.

Preparation Example 4 Preparation of 1,4-diphenyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride (DP-CBDA)

A stirrer and a cooler were installed in a 2 L quartz glass photoreactor equipped with 16 300 nm UV lamps, and 500 ml of dichloromethane and 100 g of phenylmaleic anhydride were added to the quartz glass reactor, and the mixture was stirred well. In order to prevent the temperature from rising too high due to the ultraviolet lamp, the air-cooled cooler was started first, and then the ultraviolet lamp was turned on and photoreacted while stirring well to prevent the reactant from sticking to the reactor wall for 200 hours to obtain 55 g of a white solid. The white solid obtained was filtered off and dried for 24 hours at 60 DEG C under reduced pressure. The dried solid was added to anhydrous acetic anhydride and slowly heated to 150 ° C. while melting to react for 24 hours. The reaction solution was filtered through a filter paper in a hot state and then recrystallized in a refrigerator at 0 ° C. or lower for 24 hours to obtain a white solid. The obtained solid was filtered, washed three times with toluene to remove acetic anhydride, and then dried in a vacuum oven at 60 ° C. for 48 hours to yield white 1,4-diphenyl-1,2,3,4-cyclobutanetetracarboxylic acid. 35 g of anhydrides (DP-CBDA) were obtained. The product was identified from the ¹ H-NMR spectrum (FIG. 4) for the material.

[Table 1] Chemical structure of the acid dianhydride of formula 2 according to the preparation

Soluble polyimide Photo-alignment film  Produce

The preparation of the soluble polyimide for preparing the soluble polyimide photoalignment film of the present invention is Examples 1 to 48 described in Table 2 below, the aromatic diamine monomer selected from Formulas 1 to 1 to 12 and the Preparation Example It was prepared by reacting the acid dianhydride having an aliphatic ring having a substituent prepared in 1 to Production Example 4 in a 50:50 molar ratio.

Hereinafter, the preparation and physical properties of the soluble polyimide of Examples 1 to 48 and the preparation of the optical alignment film using the same and the physical properties obtained therefrom will be described in detail through specific examples.

TABLE 2 Composition ratio of soluble polyimide prepared in Examples 1-48.

Example  1. Soluble Polyimide ( DM - SPI -One) Photo-alignment film  Produce

Preparation example while dissolving 0.01 mole of aromatic diamine of formula 1-1 in meta-cresol while slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser. 2.24 g (0.01 mole) of DM-CBDA prepared in 1 was added slowly.

At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was.

The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 3.33 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at a temperature of 30 ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-1). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example 2 Preparation of Soluble Polyimide (DM-SPI-2) Photoalignment Film

Preparation example while dissolving 0.01 mole of aromatic diamine of formula 1-2 in meta-cresol while slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser. 2.24 g (0.01 mole) of DM-CBDA prepared in 1 was added slowly. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 3.29 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at the temperature of ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-2). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example 3 Preparation of Soluble Polyimide (DM-SPI-3) Photoalignment Film

Preparation example while dissolving 0.01 mole of aromatic diamine of formula 1-3 in meta-cresol while slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser. 2.24 g (0.01 mole) of DM-CBDA prepared in 1 was added slowly. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 4.25 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at a temperature of 30 ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-3). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  4. Soluble Polyimide  ( DM - SPI -4) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 1.98 g (0.01 mole) of aromatic diamine of formula 1-4 was dissolved in meta-cresol, followed by nitrogen gas. While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried in the oven at 60 ° C. to obtain 4.22 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in a gamma-butyrolactone and 2-butoxyethanol 4: 1 solution to have a solution viscosity of 30 cps at room temperature, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at a temperature of 30 ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-4). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  5. Soluble Polyimide ( DM - SPI -5) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 2.26 g (0.01 mole) of aromatic diamine of formula 1-5 was dissolved in meta-cresol, and then nitrogen gas was While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried in the oven at 60 ° C. to obtain 4.14 g of a solid soluble polyimide resin (SPI). The prepared soluble polyimide confirmed the production of polymer from the NMR spectrum of FIG. 1 and the DSC spectrum of FIG. 2. The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cp, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 2 minutes at the temperature of ℃, 10 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DMSPI-5). Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  6. Soluble Polyimide ( DM - SPI -6) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 3.34 g (0.01 mole) of aromatic diamine of formula 1-6 was dissolved in meta-cresol, and then nitrogen gas was While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 5.58 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at a temperature of 30 ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-6). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  7. Soluble polyimide ( DM - SPI -7) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 2.27 g (0.01 mole) of aromatic diamine of formula 1-7 was dissolved in meta-cresol, and then nitrogen gas was While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 4.51 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at a temperature of 30 ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-7). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  8. Soluble Polyimide ( DM - SPI -8) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 2.92 g (0.01 mole) of aromatic diamine of formula 1-8 was dissolved in meta-cresol, and then nitrogen gas was While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 5.16 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at a temperature of 30 ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-8). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  9. Soluble Polyimide ( DM - SPI -9) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 2.92 g (0.01 mole) of aromatic diamine of the formula 1-9 was dissolved in meta-cresol, and then nitrogen gas was While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 5.16 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at a temperature of 30 ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-9). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  10. Soluble polyimide ( DM - SPI -10) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 4.32 g (0.01 mole) of aromatic diamine of the formula 1-10 was dissolved in meta-cresol, followed by nitrogen gas. While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 6.56 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 After drying for 10 minutes at a temperature of 30 ℃, 30 minutes at a temperature of 160 ℃ and irradiated with polarized ultraviolet light of 600mJ / cm ² intensity at a wavelength of 220 ~ 460nm to obtain a photo-oriented polyimide thin film (DM-SPI-10). . Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  11. Soluble Polyimide ( DM - SPI -11) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 5.18 g (0.01 mole) of aromatic diamine of formula 1-11 was dissolved in meta-cresol, and then nitrogen gas was While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 7.42 g of a solid soluble polyimide resin (SPI). The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 Soluble polyimide polyimide thin film (DM-SPI-11) photo-aligned by irradiation with polarized ultraviolet rays of 600mJ / cm ² intensity at 220-460nm wavelength after drying for 10 minutes at a temperature of 160 ° C and 30 minutes at a temperature of 160 ° C. ) Was obtained. Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  12. Soluble Polyimide DM - SPI -12) Photo-alignment film  Produce

After slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer, a nitrogen injector, a temperature controller, and a condenser, 4.11 g (0.01 mole) of aromatic diamine of the formula 1-12 was dissolved in meta-cresol, and then nitrogen gas was While passing, 2.24 g (0.01 mole) of DM-CBDA prepared in Preparation Example 1 was slowly added. At this time, the solid content was fixed at 20% by weight, and the reaction temperature was gradually increased to 2 hours at 70 ° C, 2 hours at 160 ° C, and refluxed at 200 ° C for 2 hours to obtain a liquid soluble polyimide. It was. The obtained reactant was precipitated in methanol, washed with methanol to remove meta-cresol, and dried under reduced pressure in an oven at 60 ° C. to obtain 6.35 g of a solid soluble polyimide resin. The obtained soluble polyimide powder was diluted in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution so that the solution viscosity at room temperature was 30 cps, and then spin-coated to a thickness of 0.08 μm on an ITO glass plate to obtain 90 Soluble polyimide-type polyimide thin film (DM-SPI-12) which was dried for 10 minutes at a temperature of 30 ° C. and 30 minutes at a temperature of 160 ° C., and then irradiated with polarized ultraviolet rays of 600 mJ / cm ² at a wavelength of 220 to 460 nm (DM-SPI-12). ) Was obtained. Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Example  13 ~ Example  24.

As an example corresponding to Examples 1 to 12, except for using the same molar number of DE-CBMA of Preparation Example 2 instead of DM-CBMA of Preparation Example 1, soluble polyimide-type polyimide Thin films DE-SPI-1 to DE-SPI-12 were obtained and their physical properties are shown in Table 3 below.

Example  25- Example  36.

As an example corresponding to Examples 1 to 12, except for using DPR-CBMA of Preparation Example 3 in the same molar number instead of DM-CBMA of Preparation Example 1, soluble polyimide-type polyimide Thin films DPR-SPI-1 to DPR-SPI-12 were obtained and their physical properties are shown in Table 3 below.

Example  37- Example  48.

As an example corresponding to Examples 1 to 12, soluble polyimide-type polyimide which was photo-oriented by carrying out the same procedure except using DP-CBMA of Preparation Example 4 in the same molar number instead of DM-CBMA of Preparation Example 1 Thin films DP-SPI-1 to DP-SPI-12 were obtained and their physical properties are shown in Table 3 below.

Comparative example  One. Polyamic acid  ( CPAA -One) Photo-alignment film  Produce

1.98 g (0.01 mole) of methylenedianiline was dissolved in N -methyl-2-pyrrolidone while slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer and a nitrogen injector, and then passed through nitrogen gas in a solid phase. 1.96 g (0.01 mole) of 1,2,3,4, -cyclobutanetetracarboxylic anhydride 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 (CPAA). The obtained polyamic acid solution was maintained at a solution viscosity of 30 cp at room temperature, followed by spin coating to a thickness of 0.08 μm on an ITO glass plate, followed by thermosetting at a temperature of 90 ° C. for 10 minutes and a temperature of 230 ° C. for 30 minutes. Thereafter, polarized ultraviolet rays of 1,000 mJ / cm 2 intensity were irradiated at a wavelength of 220 to 460 nm to obtain photo-oriented polyamic acid (CPAA-1). Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below.

Comparative example  2. Polyamic acid  ( CPAA -2) Photo-alignment film  Produce

2.00 g (0.01 mole) of 4,4'-oxydianiline was dissolved in the reaction solvent N-methyl-2-pyrrolidone while slowly passing nitrogen gas through a 100 ml reactor equipped with a stirrer and a nitrogen injector. 1.96 g (0.01 mole) of 1,2,3,4, -cyclobutanetetracarboxylic anhydride in solid phase was slowly added while passing through nitrogen gas. 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 (CPAA). The obtained polyamic acid solution was maintained at a solution viscosity of 30 cp at room temperature, followed by spin coating to a thickness of 0.08 μm on an ITO glass plate, followed by thermosetting at a temperature of 90 ° C. for 10 minutes and a temperature of 230 ° C. for 30 minutes. Thereafter, polarized ultraviolet rays of 1,000 mJ / cm 2 intensity were irradiated at a wavelength of 220 to 460 nm to obtain photo-oriented polyamic acid (CPAA-1). Physical properties of the prepared soluble polyimide thin film are shown in Table 3 below. In Table 3, MDT (Maximum Decomposition Temperature) is a pyrolysis temperature, and RW represents a residue after pyrolysis.

TABLE 3 Physical Properties of Polyimides According to Examples and Comparative Examples

As shown in Table 3, the polyamic acid resin according to the present invention was confirmed to have an intrinsic viscosity of 0.30 dL / g or more. In addition, the resins were found to have excellent film forming and mechanical properties by solvent casting.

As shown in Table 3, the pencil hardness of the polyimide thin films of Examples 1 to 48 in which an alkyl group was introduced into the soluble polyimide was 4H or more, and the thin films prepared from the polyamic acids of Comparative Examples 1 and 2, in which they were not introduced, were Compared with In particular, both the acid dianhydride and the diamine showed very good surface hardness characteristics of about 6H in Examples 5 and 12 in which a methyl group was introduced.

Photo-alignment film  Fabrication and Characteristic Experiment of Liquid Crystal Cell Using the Same

The soluble polyimide resin according to the present invention obtained in Examples 1 to 48 was dissolved in gamma-butyrolactone and 2-butoxyethanol 4: 1 solution to maintain a solution viscosity at room temperature of 30 cp to a thickness of 0.08 μm. After spin coating, the characteristics of the liquid crystal cell prepared by irradiating polarized ultraviolet rays to the thin film obtained by thermosetting at a temperature of 160 ° C. for 30 minutes are shown in Table 4, respectively. The wavelength of ultraviolet rays during exposure was controlled in the range of 220 ~ 460nm, The uniform orientation of the liquid crystal was observed by the amount of irradiation light of 600 to 1,000 mJ / cm ² . In the following table, VHR is Voltage Holding Rate.

In this case, the liquid crystal used was Merck E-7, and the polarized ultraviolet rays generated polarized ultraviolet rays through the polarizing plate between the thin film and the ultraviolet ray lamp. -taylor prism polarizer was used.

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.

[Table 4] Characteristics of liquid crystal cell prepared by irradiating polarized ultraviolet ray

As shown in Table 4, the liquid crystal cell prepared using the soluble polyimide according to the present invention prepared from Examples 1 to 48 showed excellent orientation in all cases, Comparative Examples 1 and Comparative Examples of the polyamic acid form Compared with 2, it showed relatively low pretilt angle and excellent voltage retention. The pretilt angle was about 0.10 to 1.0 °, which was lower than that of Comparative Example 1 and Comparative Example 2, which are in the form of polyamic acid, and the voltage retention at room temperature was 98% or more, which is higher than that of Comparative Example 1 and Comparative Example 2. It was. In addition, Examples 5 and 12 in which the methyl group was introduced into the acid dianhydride and the diamine showed better voltage retention than those of Examples 1 to 4 and Examples 6 to 11 in which the methyl group was introduced only into the acid dianhydride.

That is, the liquid crystal cell using the polyimide alignment film prepared from the soluble polyimide of Examples 1 to 48 prepared in the present invention is required to have a low linear tilt angle and a high voltage retention in in plane switching (IPS), TFT- It was confirmed that the film exhibited characteristics suitable for use as a liquid crystal alignment film for TN and STN LCD.

As described above, the present invention exhibits excellent low temperature processability compared to the existing process, and at the same time, it has not only excellent high surface hardness, light transmittance, heat resistance, and mechanical properties, but also excellent light orientation property, low pretilt angle and excellent voltage retention. A new type of liquid crystal aligning film has been produced, and it has been found to be useful as a liquid crystal aligning film for in-plane switching (IPS) TFT-TN and STN LCD and various advanced heat-resistant structure materials requiring demanding electro-optical properties.

In addition, the aliphatic ring-soluble polyimide photoalignment film prepared in the present invention is a variety of electric. It is expected to have a wide range of applications in various forms such as functional coatings as an essential material for miniaturization, light weight, and high reliability of electronics products, especially electronics.

Although the present invention has been described in detail only with respect to the above-described embodiments, 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. .

Claims (10)

(A) dissolving the aliphatic ring-based polyimide resin for low-temperature process containing a unit of formula (1) at room temperature in an organic solvent containing an aprotic polar solvent; (b) coating the dissolved polyimide resin on an ITO glass plate; And (c) irradiating polarized ultraviolet rays after drying the coated polyimide resin; Method for producing an aliphatic ring-soluble polyimide photoalignment film for a low temperature process comprising a. [Formula 1]

[In Formula 1 m is a natural number in the range of 1 to 500; R ₁ to R ₄ are each independently hydrogen, C ₁ ~ C ₃₀ linear or branched saturated or unsaturated alkyl group, C ₆ ~ C ₁₂ aryl group, C ₁ ~ C ₃₀ alkoxy substituted C ₆ ~ C ₃₀ is an aryl group, wherein all of the aryl groups may be substituted with a linear or branched, saturated or unsaturated alkyl group, ester group, carbonyl group, halogen or amino group of C ₁ to C ₃₀ ;

silver

 It includes one or more aromatic divalent groups selected from.]  The method of claim 1, R ₁ R ₄ to R ₄ are independently selected from hydrogen, a C ₁ to C ₃ alkyl group, and a phenyl group. The method of claim 1, The aliphatic ring-soluble polyimide resin for low temperature process has an intrinsic viscosity of 0.3 to 2.0 dL / g, and has a weight average molecular weight of 10,000 to 500,000 g / mol. Manufacturing method. The method of claim 1, The aprotic polar solvent is selected from dimethylacetamide (DMAc), dimethylformamide (DMF), N -methyl-2-pyrrolidone (NMP) and gamma-butyrolactone or mixtures thereof. Method for producing aliphatic soluble polyimide photoalignment film for low temperature process. The method of claim 1, The polarizing ultraviolet ray is prepared by irradiating an irradiation amount of 100 to 2,000 mJ / ㎠ at a wavelength of 220 to 460nm, a method for producing an aliphatic ring-soluble polyimide photoalignment film for low temperature process. An aliphatic ring-based soluble polyimide photoalignment film for a low temperature process prepared by the method of any one of claims 1 to 5. The method of claim 6, The photo-alignment layer is an optical alignment layer having a pencil strength of 4 to 6H. A liquid crystal cell comprising the photoalignment film of claim 6. The method of claim 8, The liquid crystal cell has a pretilt angle of 0.01 to 1 °. The method of claim 8, The liquid crystal cell has a voltage retention of 98 to 99.5% at 25 ° C. and a 3V voltage.

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