KR101887720B1 - Liquid crystal alignment agent containing both polyamic acid ester and polyamic acid - Google Patents

Abstract

(X₁ 및 X₂ 는 각각 독립적으로 4 가의 유기기이고, Y₁ 및 Y₂ 는 각각 독립적으로 2 가의 유기기이고, A₁, A₂ 는 각각 독립적으로, 수소 원자, 또는 치환기를 가져도 되는 탄소수 1 ∼ 10 의 알킬기, 알케닐기, 혹은 알키닐기이고, R₁ 은 메틸기이다)Disclosed is a liquid crystal aligning agent capable of reducing fine irregularities on the surface of a liquid crystal alignment film, improving liquid crystal alignability, improving electrical properties, and improving reliability.
A polyimide resin composition comprising a polyamic acid ester having a repeating unit represented by the following formula (1) and a polyamic acid having a repeating unit represented by the following formula (2), wherein the polyamic acid ester has a divalent organic group (Y ₁ ) The divalent organic group (Y ₂ ) of the polyamic acid is characterized in that at least 60 mol% thereof has the same structure.
(Formula 1)

(Wherein X ₁ and X ₂ are each independently a tetravalent organic group, Y ₁ and Y ₂ are each independently a divalent organic group, and A ₁ and A ₂ are each independently a hydrogen atom, An alkyl group having 1 to 10 carbon atoms, an alkenyl group or an alkynyl group, and R ₁ is a methyl group)

Description

TECHNICAL FIELD [0001] The present invention relates to a liquid crystal aligning agent containing a polyamic acid ester and a polyamic acid,

The present invention relates to a liquid crystal aligning agent containing a polyamic acid ester and a polyamic acid, and a liquid crystal alignment film obtained from the liquid crystal aligning agent.

In a liquid crystal display element used in a liquid crystal television, a liquid crystal display, or the like, a liquid crystal alignment film for controlling the alignment state of liquid crystals is usually formed in the element. As the liquid crystal alignment layer, a liquid crystal alignment layer mainly composed of a solution of a polyimide precursor such as polyamic acid (polyamic acid) or a soluble polyimide is coated on a glass substrate or the like, and a polyimide-based liquid crystal alignment layer .

In view of the demand for reduction of contrast of a liquid crystal display element and reduction of afterimage phenomenon accompanying demand for high definition of a liquid crystal display element, in liquid crystal alignment films, in addition to excellent liquid crystal alignability and stable expression of a pretilt angle, Characteristics such as suppression of residual image caused by AC driving, low residual charge when a direct current voltage is applied, and / or rapid relaxation of accumulated residual charge due to a direct current voltage have become increasingly important.

In the polyimide-based liquid crystal alignment film, various proposals have been made in order to cope with the above-mentioned demands. For example, a liquid crystal aligning agent containing a tertiary amine having a specific structure in addition to a polyamic acid or an imide group-containing polyamic acid is used as a liquid crystal alignment film having a short time until the after-image caused by the DC voltage disappears (See, for example, Patent Document 1), and a liquid crystal aligning agent containing a soluble polyimide using, as a raw material, a specific diamine compound having a pyridine skeleton or the like (see, for example, Patent Document 2) have. In addition, as a liquid crystal alignment film having a high voltage holding ratio and a short time until the after-image caused by the DC voltage disappears, a liquid crystal alignment film containing a compound containing one carboxylic acid group in the molecule, (See, for example, Patent Document 3) which uses a liquid crystal aligning agent containing a very small amount of a compound containing one carboxylic acid anhydride group and a compound containing one tertiary amino group in the molecule have. Also disclosed is a liquid crystal alignment film having excellent liquid crystal alignability, high voltage holding ratio, low residual image, excellent reliability, and exhibiting a high pretilt angle, and is a liquid crystal alignment film comprising tetracarboxylic dianhydride having a specific structure and tetracarboxylic There is known a polyamic acid obtained from an acid dianhydride and a specific diamine compound or a liquid crystal aligning agent containing the imidized polymer (see, for example, Patent Document 4). As a method for suppressing the afterimage due to the AC driving which occurs in the liquid crystal display element of the transversal electric field driving system, there is a method of using a specific liquid crystal alignment film having good liquid crystal alignability and high interaction with liquid crystal molecules 5) has been proposed.

In addition to the above, recently, a large-screen, high-precision liquid crystal television becomes the main body, and the demand for the afterimage becomes stricter, and a characteristic capable of enduring long-term use in a harsh environment is demanded. Accordingly, the liquid crystal alignment film to be used needs to have higher reliability than the conventional one. The properties of the liquid crystal alignment film are required not only to have good initial characteristics but also to maintain good properties even after prolonged exposure at a high temperature, for example.

On the other hand, as the polymer component constituting the polyimide-based liquid crystal aligning agent, the polyamic acid ester has high reliability and does not cause a decrease in the molecular weight by the heat treatment at the time of imidization, so that the liquid crystal alignment stability and reliability (See Patent Document 6). However, the polyamic acid ester generally has a problem that the volume resistivity is high and the relaxation of the residual charge accumulated by the DC voltage is slow. A method for improving the relaxation characteristics of residual charges in a polyimide-based liquid crystal aligning agent containing such a polyamic acid ester is not yet known.

Japanese Patent Application Laid-Open No. 9-316200 Japanese Patent Application Laid-Open No. 10-104633 Japanese Patent Application Laid-Open No. 8-76128 Japanese Patent Application Laid-Open No. 9-138414 Japanese Laid-Open Patent Publication No. 11-38415 Japanese Patent Application Laid-Open No. 2003-26918

The present inventors have found that a polyamic acid which is superior in terms of electrical characteristics to a polyamic acid ester can be blended as a means for improving the relaxation property of residual charge which is a difficult point while maintaining the orientation stability and high reliability of the liquid crystal, One liquid crystal aligning agent was noted. However, it has been confirmed that the contrast of a liquid crystal display device using a liquid crystal alignment film obtained from a liquid crystal alignment agent blended with such a polyamic acid ester and a polyamic acid is lowered.

As a result of analyzing the reason for the lowering of the contrast of the liquid crystal display element, it was found that fine unevenness occurred on the surface of the liquid crystal alignment film causing the decrease in contrast, and since the liquid crystal molecules were disturbed from the alignment treatment direction by the minute unevenness, The contrast is lowered.

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a liquid crystal aligning agent containing a polyamic acid ester and a polyamic acid which exhibits both excellent liquid crystal alignability and electrical properties and also exhibits remarkably small irregularities which cause a decrease in contrast on the surface of a liquid crystal alignment film And a liquid crystal aligning agent capable of obtaining a liquid crystal alignment film having a reduced crystallinity.

According to the study by the present inventors, the fine irregularities appearing on the surface of the liquid crystal alignment film formed from a liquid crystal aligning agent containing a polyamic acid ester and a polyamic acid are not particularly limited as long as the specific unevenness of the polyamic acid ester and the polyamic acid contained in the liquid crystal aligning agent The inventors have found that the above difficulties of the liquid crystal aligning agent containing the polyamic acid ester and the polyamic acid can be solved.

Thus, the present invention is based on the above findings, and has the following points.

1. A polyamic acid ester comprising a polyamic acid ester having a repeating unit represented by the following formula (1) and a polyamic acid having a repeating unit represented by the following formula (2), wherein the polyamic acid ester has a divalent organic group (Y ₁ ) Wherein at least 60 mol% of the divalent organic group (Y ₂ ) of the polyamic acid has the same structure.

delete

(In the formulas (1) and (2), X ₁ and X ₂ are each independently a tetravalent organic group, Y ₁ and Y ₂ are each independently a divalent organic group, and A ₁ and A ₂ are Independently, a hydrogen atom, or an alkyl group, alkenyl group or alkynyl group having 1 to 10 carbon atoms which may have a substituent, and R ₁ is a methyl group)

2. The liquid crystal aligning agent according to 1 above, wherein the content of the polyamic acid ester and the content of the polyamic acid is 1/9 to 9/1 in terms of a mass ratio of (polyamic acid ester content / polyamic acid content).

3. The liquid crystal according to the item 1 or 2 and having the polyamic acid ester is a tetravalent organic group (X ₁₎ with the polyamic acid is a tetravalent organic group having the mixer (X ₂₎ have the same structure, that at least 60 mol% Orientation agent.

4. The liquid crystal aligning agent according to any one of 1 to 3 above, further comprising an organic solvent, wherein the total content of the polyamic acid ester and the polyamic acid is 0.5 to 15 mass% with respect to the organic solvent.

5. The liquid crystal alignment according to any one of 1 to 4 above, wherein X ₁ and X ₂ in formulas (1) and (2) are each independently at least one selected from the structures represented by the following formulas My.

(2)

6. The liquid crystal alignment according to any one of 1 to 5 above, wherein Y ₁ and Y ₂ in the formulas (1) and (2) are each independently at least one selected from the structures represented by the following formulas My.

(3)

7. A liquid crystal alignment film obtained by applying and firing the liquid crystal aligning agent according to any one of 1 to 6 above.

According to the present invention, it is possible to reduce the fine irregularities on the surface of the obtained liquid crystal alignment film, to improve the liquid crystal alignment property, and to improve the contrast Can be suppressed, and a liquid crystal aligning agent with improved reliability can be provided.

It is not necessarily clear whether the liquid crystal aligning agent of the present invention can suppress fine irregularities occurring on the surface of the resulting liquid crystal alignment film and solves the difficulty of the liquid crystal aligning agent containing the polyamic acid ester and the polyamic acid , It is thought to be approximately as follows.

On the surface of the liquid crystal alignment film formed by removing the solvent from the liquid crystal aligning agent dissolved in the polyamic acid ester and the polyamic acid, the ratio of the polyamic acid ester having a lower surface free energy than the polyamic acid is large, but the polyamic acid ester and polyamic acid The mountains are mixed. Since the polyamic acid ester and the polyamic acid undergo phase separation, an aggregate of polyamic acid is formed in the polyamic acid ester phase or an aggregate of polyamic acid ester is formed in the polyamic acid phase, so that there are many fine irregularities on the surface Thereby forming a liquid crystal alignment film.

On the contrary, in the liquid crystal aligning agent of the present invention, when the solvent is removed from the liquid crystal aligning agent and the liquid crystal alignment film is formed by increasing the identity in the molecular structure of the specific part of the polyamic acid ester and the polyamic acid, Phase separation of the mixed acid ester and the polyamic acid is suppressed. As a result, the vicinity of the surface of the formed liquid crystal alignment film is a mixed phase of polyamic acid ester and polyamic acid, but polyamic acid ester exists in a larger ratio than polyamic acid.

Therefore, the surface of the resulting liquid crystal alignment film is smoothed because the formation of unevenness due to the phase separation of the polyamic acid ester and the polyamic acid is remarkably suppressed, and the lowering of the contrast caused by the unevenness is also reduced. In addition, the resulting liquid crystal alignment film has many polyamic acid esters excellent in orientation stability and reliability on the surface of the film, and also contains a large amount of polyamic acid having excellent electrical properties in the film. Therefore, .

≪ Polyamic acid ester and polyamic acid &

The polyamic acid ester used in the present invention is a polyimide precursor for obtaining a polyimide and is a polymer having a site capable of undergoing an imidization reaction as described below by heating.

[Chemical Formula 4]

The polyamic acid ester and the polyamic acid contained in the liquid crystal aligning agent of the present invention each have the following formula (1) and the following formula (2).

delete

In the above formula (1), as the number of carbon atoms of R ₁ increases, the temperature at which the imidization proceeds is increased in the polyamic acid ester. Therefore, from the viewpoint of easy imidization by heat, R ₁ needs to be a methyl group.

In the formulas (1) and (2), A ₁ and A ₂ are each independently a hydrogen atom or an alkyl group, alkenyl group or alkynyl group having 1 to 10 carbon atoms which may have a substituent. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a t-butyl group, a hexyl group, an octyl group, a decyl group, a cyclopentyl group, a cyclohexyl group and a bicyclohexyl group. Examples of the alkenyl group include those obtained by substituting at least one CH-CH structure in the alkyl group with a C = C structure, and more specifically, a vinyl group, allyl group, 1-propenyl group, , 2-butenyl, 1,3-butadienyl, 2-pentenyl, 2-hexenyl, cyclopropenyl, cyclopentenyl and cyclohexenyl. Examples of the alkynyl group include those wherein at least one CH ₂ -CH ₂ structure existing in the alkyl group is substituted with a C≡C structure. More specifically, an ethynyl group, 1-propynyl group, 2-propynyl group, .

The alkyl group, alkenyl group and alkynyl group may have a substituent group when the number of carbon atoms is 1 to 10 as a whole, or may form a ring structure by a substituent group. The formation of a ring structure by a substituent means that a substituent group or a substituent group and a part of the parent skeleton are bonded to form a ring structure.

Examples of the substituent include a halogen group, a hydroxyl group, a thiol group, a nitro group, an aryl group, an organoxy group, an organotio group, an organosilyl group, an acyl group, an ester group, a thioester group, , An alkenyl group, and an alkynyl group.

Examples of the halogen group as a substituent include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom.

As the aryl group as a substituent, a phenyl group can be mentioned. These aryl groups may be further substituted with other substituents described above.

The organoxy group as a substituent may represent a structure represented by -O-R. As R, examples of the alkyl group, alkenyl group, alkynyl group, aryl group and the like can be mentioned. These R may be further substituted with the aforementioned substituents. Specific examples of the organoxy group include a methoxy group, ethoxy group, propyloxy group, butoxy group, pentyloxy group, hexyloxy group, heptyloxy group and octyloxy group.

The organotio group which is a substituent may represent a structure represented by -S-R. As R, examples of the alkyl group, alkenyl group, alkynyl group, aryl group and the like can be mentioned. These R may be further substituted with the aforementioned substituents. Specific examples of the organotitanium group include methylthio group, ethylthio group, propylthio group, butylthio group, pentylthio group, hexylthio group, heptylthio group and octylthio group.

The organosilyl group as a substituent may represent a structure represented by -Si- (R) ₃ . These R may be the same or different and are the above-mentioned alkyl, alkenyl, alkynyl, aryl and the like. These R may be further substituted with the aforementioned substituents. Specific examples of the organosilyl group include a trimethylsilyl group, a triethylsilyl group, a tripropylsilyl group, a tributylsilyl group, a tripentylsilyl group, a trihexylsilyl group, a pentyldimethylsilyl group, a hexyldimethylsilyl group, .

The acyl group as a substituent may represent a structure represented by -C (O) -R. As R, examples of the alkyl group, alkenyl group, aryl group, and the like may be mentioned. These R may be further substituted with the aforementioned substituents. Specific examples of the acyl group include a formyl group, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, a valeryl group, an isovaleryl group, and a benzoyl group.

The ester group as a substituent may represent a structure represented by -C (O) O-R or -OC (O) -R. As R, examples of the alkyl group, alkenyl group, alkynyl group, aryl group and the like can be mentioned. These R may be further substituted with the aforementioned substituents.

The thioester group which is a substituent may represent a structure represented by -C (S) O-R or -OC (S) -R. As R, examples of the alkyl group, alkenyl group, alkynyl group, aryl group and the like can be mentioned. These R may be further substituted with the aforementioned substituents.

The phosphoric acid ester group which is a substituent may represent a structure represented by -OP (O) - (OR) ₂ . These R may be the same or different and are the above-mentioned alkyl, alkenyl, alkynyl, aryl and the like. These R may be further substituted with the aforementioned substituents.

Examples of the amide group as the substituent include a group represented by -C (O) NH ₂ or a group represented by -C (O) NHR, -NHC (O) R, -C (O) N (R) ₂ or -NRC Lt; / RTI > These R may be the same or different and are the above-mentioned alkyl, alkenyl, alkynyl, aryl and the like. These R may be further substituted with the aforementioned substituents.

Examples of the aryl group as the substituent include the same aryl groups as those described above. These aryl groups may be further substituted with other substituents described above.

Examples of the alkyl group as the substituent include the same alkyl groups mentioned above. These alkyl groups may be further substituted with other substituents described above.

Examples of the alkenyl group as the substituent include the same alkenyl groups as those described above. This alkenyl group may be further substituted with another substituent as described above.

Examples of the alkynyl group as the substituent include the same alkynyl groups as mentioned above. These alkynyl groups may be further substituted with other substituents described above.

In general, when introducing a bulky structure, there is a possibility that the reactivity of the amino group and the liquid crystal orientation may be lowered. Therefore, as A ₁ and A ₂ , a hydrogen atom or an alkyl group having 1 to 5 carbon atoms which may have a substituent is more preferable And a hydrogen atom, a methyl group or an ethyl group is particularly preferable.

In the formulas (1) and (2), X ₁ and X ₂ each independently represent a tetravalent organic group. X ₁ and X ₂ may be the same or different or two or more kinds may be mixed. However, in order to suppress the generation of unevenness that occurs on the surface of the liquid crystal alignment film to be obtained, the structures of X ₁ and X ₂ are preferably the same as each other and preferably 60% or more, particularly 80% or more Good.

Whether X ₁ and X ₂ are the same or not may not necessarily be completely the same, and may be, for example, a side chain or a substituent which has no influence on the whole, so long as the effect of the present invention is not impaired.

Specific examples of X ₁ and X ₂ include X-1 to X-46 shown below. X ₁ , X ₂ , X 6, X 16, X 18, X 19, X 26, X 27, and X 27 are each independently selected from the viewpoint of liquid crystal alignability. Or X-46 is preferable, and X-1, X-2, X-16, X-26, X-27 or X-46 are more preferable.

[Chemical Formula 6]

(7)

[Chemical Formula 8]

[Chemical Formula 9]

In the formula (1), Y ₁ and Y ₂ each independently represent a divalent organic group and are not particularly limited. Y ₁ and Y ₂ may be the same or different, and two or more kinds may be mixed. However, in order to suppress the occurrence of the irregularities generated on the surface of the liquid crystal alignment film to be obtained, the structures of Y ₁ and Y ₂ are preferably the same as each other, preferably 60% or more, more preferably 70% , Particularly preferably 80% or more. Whether Y ₁ and Y ₂ are the same or not may not necessarily be completely the same, and may include, for example, a side chain or a substituent which is entirely unaffected so long as the effect of the present invention is not impaired.

Specific examples of Y ₁ and Y ₂ include the following Y-1 to Y-99. Y ₁ , Y ₂ , Y ₃ , Y ₃ , Y ₄ , Y ₄ , Y 5, Y 6, Y 6, , Y-66, Y-68, Y-72, Y-72, Y- 98 is more preferable.

Y ₁ , and Y _{2 may} be independently selected from the group consisting of Y-20, Y-21, Y-25, Y-27, Y-28, Y-29, Y-99 is preferable, and Y-28, Y-29, Y-31 or Y-99 is more preferable.

[Chemical formula 10]

(11)

[Chemical Formula 12]

[Chemical Formula 13]

[Chemical Formula 14]

[Chemical Formula 15]

[Chemical Formula 16]

[Chemical Formula 17]

[Chemical Formula 18]

[Chemical Formula 19]

[Chemical Formula 20]

[Chemical Formula 21]

<Production method of polyamic acid ester>

The polyamic acid ester represented by the formula (1) can be obtained by reacting any of the tetracarboxylic acid derivatives represented by the following formulas (6) to (8) with a diamine compound represented by the formula (9).

[Chemical Formula 22]

(23)

(Wherein X ₁ , Y ₁ , R ₁ , A ₁ and A ₂ are the same as defined in the formula (1)

The polyamic acid ester represented by the above formula (1) can be synthesized by the following methods (1) to (3) using the above monomers.

(1) Synthesis from polyamic acid

The polyamic acid ester can be synthesized by esterifying a polyamic acid obtained from a tetracarboxylic acid dianhydride and a diamine.

&Lt; EMI ID =

Concretely, the polyamic acid and the esterifying agent are reacted in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C for 30 minutes to 24 hours, preferably 1 to 4 hours .

The esterifying agent is preferably one which can be easily removed by purification. Examples of the esterifying agent include N, N-dimethylformamide dimethylacetal, N, N-dimethylformamide diethyl acetal, N, N-dimethylformamide dipropyl acetal, N, N-dimethylformamide dineopentylbutyl acetal, N, N-dimethylformamide di-t-butyl acetal, 1-methyl-3-p-tolyltriazine, , 1-propyl-3-p-tolyltriazine, and 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride. The addition amount of the esterifying agent is preferably 2 to 6 molar equivalents relative to 1 mol of the repeating unit of the polyamic acid.

The organic solvent to be used in the reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone or γ-butyrolactone from the solubility of the polymer, May be used. The concentration at the time of synthesis is preferably from 1 to 30% by mass, and more preferably from 5 to 20% by mass, from the viewpoint that the precipitation of the polymer does not occur well and the high molecular weight material is easily obtained.

(2) Synthesis by reaction of tetracarboxylic acid diester dichloride with diamine

Polyamic acid esters can be synthesized from tetracarboxylic acid diester dichloride and diamines.

(25)

Specifically, the tetracarboxylic acid diester dichloride and diamine are reacted in the presence of a base and an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C for 30 minutes to 24 hours, For 4 hours.

As the base, pyridine, triethylamine, 4-dimethylaminopyridine and the like can be used, but pyridine is preferred since the reaction proceeds mildly. The addition amount of the base is preferably 2 to 4 times the amount of the tetracarboxylic acid diester dichloride from the viewpoint of easy removal and high molecular weight.

The organic solvent to be used in the reaction is preferably N-methyl-2-pyrrolidone or? -Butyrolactone from the viewpoint of the solubility of the monomer and the polymer, and they may be used alone or in combination of two or more. The concentration of the polymer in the synthesis is preferably from 1 to 30 mass%, more preferably from 5 to 20 mass%, from the viewpoint that the precipitation of the polymer does not occur well and the high molecular weight material is easily obtained. In order to prevent the hydrolysis of the tetracarboxylic acid diester dichloride, the organic solvent used for the synthesis of the polyamic acid ester is desirably dehydrated as much as possible. The reaction is preferably carried out in a nitrogen atmosphere to prevent the incorporation of outside air desirable.

(3) When synthesized by the reaction of a tetracarboxylic acid diester and a diamine

The polyamic acid ester can be synthesized by polycondensation of a tetracarboxylic acid diester and a diamine.

(26)

Specifically, the tetracarboxylic acid diester and diamine are reacted in the presence of a condensing agent, a base and an organic solvent at 0 ° C to 150 ° C, preferably 0 ° C to 100 ° C for 30 minutes to 24 hours, For 15 hours.

Examples of the condensing agent include triphenylphosphite, dicyclohexylcarbodiimide, 1-ethyl-3- (3- dimethylaminopropyl) carbodiimide hydrochloride, N, N'-carbonyldiimidazole, dimethoxy- N, N ', N'-tetramethyluronium tetrafluoroborate, O- (benzotriazol-1-yl) 1-yl) -N, N, N ', N'-tetramethyluronium hexafluorophosphate and (2,3-dihydro-2-thioxo-3-benzoxazolyl) . The amount of the condensing agent to be added is preferably 2 to 3 times the mole of the tetracarboxylic acid diester.

As the base, tertiary amines such as pyridine and triethylamine can be used. The amount of the base to be added is preferably 2 to 4 times the amount of the diamine component from the viewpoint of easy removal and high molecular weight.

The organic solvent to be used in the reaction is preferably N-methyl-2-pyrrolidone or? -Butyrolactone from the viewpoint of the solubility of the monomer and the polymer, and they may be used alone or in combination of two or more.

In addition, in the above reaction, the reaction proceeds efficiently by adding Lewis acid as an additive. As the Lewis acid, lithium halides such as lithium chloride and lithium bromide are preferable. The addition amount of the Lewis acid is preferably 0.1 to 1.0 times the amount of the diamine component.

Among the methods for synthesizing the above three polyamic acid esters, the synthesis method of the above (1) or (2) is particularly preferable because a high molecular weight polyamic acid ester can be obtained.

The solution of the polyamic acid ester obtained as described above can be precipitated by injecting it into a poor solvent while stirring well. Precipitation is carried out several times, washed with a poor solvent, and then heated or dried at room temperature to obtain a purified polyamic acid ester powder. Examples of the poor solvent include, but are not limited to, water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Production method of polyamic acid>

The polyamic acid represented by the formula (2) can be obtained by reacting the tetracarboxylic acid dianhydride represented by the following formula (10) with the diamine compound represented by the formula (11).

(27)

Specifically, the tetracarboxylic acid dianhydride and the diamine are reacted in the presence of an organic solvent at -20 ° C to 150 ° C, preferably 0 ° C to 50 ° C for 30 minutes to 24 hours, preferably 1 to 12 hours Can be synthesized.

The organic solvent used in the above reaction is preferably N, N-dimethylformamide, N-methyl-2-pyrrolidone or? -Butyrolactone from the solubility of the monomer and the polymer, They may be mixed and used. The concentration of the polymer is preferably from 1 to 30 mass%, more preferably from 5 to 20 mass%, from the viewpoint that the precipitation of the polymer does not occur well and the high molecular weight material is easily obtained.

The polyamic acid thus obtained can be recovered by precipitating a polymer by injecting the reaction solution into a poor solvent while stirring well. In addition, precipitation is carried out several times, followed by washing with a poor solvent, and then heating or drying at room temperature to obtain a purified polyamic acid powder. Examples of the poor solvent include, but are not limited to, water, methanol, ethanol, hexane, butyl cellosolve, acetone, and toluene.

<Liquid Crystal Aligner>

The liquid crystal aligning agent of the present invention contains a polyamic acid ester represented by the formula (1) and a polyamic acid represented by the formula (2).

The weight average molecular weight of the polyamic acid ester is preferably 5,000 to 300,000, and more preferably 10,000 to 200,000. The number average molecular weight is preferably 2,500 to 150,000, more preferably 5,000 to 10,000.

On the other hand, the weight average molecular weight of the polyamic acid is preferably 10,000 to 305,000, more preferably 20,000 to 210,000. The number average molecular weight is preferably 5,000 to 152,500, and more preferably 10,000 to 105,000.

In the liquid crystal aligning agent of the present invention, the content of the polyamic acid ester and the content of the polyamic acid are preferably in the range of 1/9 to 9/1, more preferably in the mass ratio of (polyamic acid ester / polyamic acid) Preferably 2/8 to 8/2, and particularly preferably 3/7 to 7/3. When the ratio is within this range, it is possible to provide a liquid crystal aligning agent having both excellent liquid crystal alignability and electrical characteristics.

The liquid crystal aligning agent of the present invention is in the form of a solution in which the polyamic acid ester and the polyamic acid are dissolved in an organic solvent. When the polyamic acid ester and / or polyamic acid is synthesized in an organic solvent, for example, the reaction solution itself may be obtained, and the reaction solution may be diluted with an appropriate solvent so long as it has this form. When a polyamic acid ester and / or polyamic acid is obtained as a powder, it may be dissolved in an organic solvent to form a solution.

The content (concentration) of the polyamic acid and the polyamic acid ester (hereinafter also referred to as polymer) in the liquid crystal aligning agent of the present invention can be appropriately changed depending on the setting of the thickness of the polyimide film to be formed, The content of the polymer component in the organic solvent is preferably 0.5% by mass or more, more preferably 15% by mass or less, more preferably 1 to 10% by mass in view of the storage stability of the solution % to be. In this case, it is also possible to prepare a polymer-rich solution in advance, and to dilute the solution when the liquid-crystal aligning agent is used from such a concentrated solution. The concentration of the concentrated solution of the polymer component is preferably 10 to 30% by mass, more preferably 10 to 15% by mass. Further, the polymer component powder may be heated in dissolving in an organic solvent to prepare a solution. The heating temperature is preferably 20 占 폚 to 150 占 폚, and particularly preferably 20 占 폚 to 80 占 폚.

The organic solvent contained in the liquid crystal aligning agent of the present invention is not particularly limited as long as the polymer component is uniformly dissolved. Specific examples thereof include N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, N-methyl- , N-methylcaprolactam, 2-pyrrolidone, N-vinyl-2-pyrrolidone, dimethylsulfoxide, dimethylsulfone,? -Butyrolactone, 1,3-dimethyl-imidazolidinone, N, N-dimethylpropanamide, and the like. These may be used alone or in combination of two or more. The solvent may be mixed with the above-mentioned organic solvent as long as the solvent alone can not dissolve the polymer component uniformly and the polymer can not be precipitated.

The liquid crystal aligning agent of the present invention may contain, in addition to the organic solvent for dissolving the polymer component, a solvent for improving the uniformity of the coating film when the liquid crystal aligning agent is applied to the substrate. Such a solvent generally uses a solvent having a lower surface tension than the organic solvent. Specific examples thereof include ethyl cellosolve, butyl cellosolve, butyl cellosolve acetate, ethyl carbitol, butyl carbitol, ethyl carbitol acetate, ethylene glycol, 1-methoxy-2-propanol, 1- 2-propanol, 1-phenoxy-2-propanol, propylene glycol monoacetate, propylene glycol diacetate, propylene glycol-1-monomethyl ether-2-acetate, propylene glycol- Lactic acid methyl ester, lactic acid ethyl ester, lactic acid n-propyl ester, lactic acid n-butyl ester, lactic acid isoamyl ester, lactic acid ethyl ester-2-acetate, dipropylene glycol, 2- (2- ethoxypropoxy) propanol, Esters and the like. These solvents may be used in combination of two or more.

The liquid crystal aligning agent of the present invention may contain various additives such as a silane coupling agent and a crosslinking agent. The silane coupling agent is added for the purpose of improving adhesion between the substrate to which the liquid crystal aligning agent is applied and the liquid crystal alignment film formed thereon. Specific examples of the silane coupling agent are given below, but the present invention is not limited thereto.

Aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3- (2-aminoethyl) aminopropyltrimethoxysilane, 3- Amine-based silane coupling agents such as phenylaminopropyltrimethoxysilane, 3-triethoxysilyl-N- (1,3-dimethyl-butylidene) propylamine and 3-aminopropyldiethoxymethylsilane; Vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, vinylmethyldimethoxysilane, vinyltriacetoxysilane, vinyltriisopropoxysilane, allyltrimethoxysilane, p Vinyl silane coupling agents such as styryltrimethoxysilane; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4 - epoxycyclohexyl) ethyl trimethoxysilane; Methacrylic silane coupling agents such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane. Ring agent; Acrylic silane coupling agents such as 3-acryloxypropyltrimethoxysilane; A ureido-based silane coupling agent such as 3-ureidopropyltriethoxysilane; Sulfide-based silane coupling agents such as bis (3- (triethoxysilyl) propyl) disulfide, and bis (3- (triethoxysilyl) propyl) tetrasulfide; Mercapto-based silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane and 3-octanoylthio-1-propyltriethoxysilane; Isocyanate-based silane coupling agents such as 3-isocyanatepropyltriethoxysilane and 3-isocyanatepropyltrimethoxysilane; Aldehyde-based silane coupling agents such as triethoxysilylbutylaldehyde; Carbamate-based silane coupling agents such as triethoxysilylpropylmethyl carbamate and (3-triethoxysilylpropyl) -t-butylcarbamate.

When the amount of the silane coupling agent is too large, the unreacted portion may adversely affect the liquid crystal alignability. If the silane coupling agent is too small, the silane coupling agent may not exhibit an adherence to the adhesion, so that the amount is preferably 0.01 to 5.0 wt% More preferably 0.1 to 1.0% by weight.

In the case of adding the silane coupling agent, it is preferable to add the silane coupling agent before the addition of the solvent for improving the uniformity of the coating film in order to prevent precipitation of the polymer. When a silane coupling agent is added, it may be added to both of a polyamic acid ester solution, a polyamic acid solution, or a polyamic acid ester solution and a polyamic acid solution before mixing the polyamic acid ester solution and the polyamic acid solution. It may also be added to a polyamic acid ester-polyamic acid mixed solution. Since the silane coupling agent is added for the purpose of improving the adhesion between the polymer and the substrate, the silane coupling agent is added to the polyamic acid solution which can be localized in the film and at the substrate interface, and a polymer and a silane coupling agent It is more preferable to mix it with the polyamic acid ester solution after sufficiently reacting.

An imidization accelerator may be added in order to efficiently progress the imidization of the polyamic acid ester when the coating film is baked. Specific examples of the imidization accelerator of the polyamic acid ester are shown below, but the present invention is not limited thereto.

(28)

[Chemical Formula 29]

In the formulas (B-1) to (B-17), D is independently a tert-butoxycarbonyl group or a 9-fluorenylmethoxycarbonyl group. In the formulas (B-14) to (B-17), a plurality of D's are present in one formula, but they may be the same or different.

The content of the imidization promoter is not particularly limited as long as the effect of accelerating the thermal imidization of the polyamic acid ester can be obtained. However, the amount of the imidization promoter is not limited so long as 1 mol of the amic ester moiety of the following formula (12) contained in the polyamic acid ester in the liquid crystal aligning agent Preferably 0.01 mol or more, more preferably 0.05 mol or more, and still more preferably 0.1 mol or more. In addition, in view of keeping the adverse effect promoter itself remaining in the film after firing itself to a minimum in the characteristics of the liquid crystal alignment film, the amic ester moiety of the formula (12) contained in the polyamic acid ester in the liquid crystal aligning agent Is preferably 2 mol or less, more preferably 1 mol or less, and still more preferably 0.5 mol or less, based on 1 mol of the imidization accelerator.

(30)

When an imidization accelerator is added, since imidization may proceed by heating, it is preferable to add it after diluting with a good solvent and a poor solvent.

&Lt; Liquid crystal alignment film &

The liquid crystal alignment film of the present invention is a film obtained by applying the liquid crystal aligning agent to a substrate, followed by drying and firing. The substrate to which the liquid crystal aligning agent of the present invention is applied is not particularly limited as long as it is a substrate having high transparency. A plastic substrate such as a glass substrate, a silicon nitride substrate, an acrylic substrate or a polycarbonate substrate can be used. It is preferable from the viewpoint of simplification of the process. In the reflection type liquid crystal display element, if it is only on one side of the substrate, opaque materials such as a silicon wafer can be used. In this case, a material that reflects light such as aluminum can also be used.

Examples of the application method of the liquid crystal aligning agent of the present invention include a spin coating method, a printing method, and an ink jet method. The drying and firing steps after the application of the liquid crystal aligning agent of the present invention can be carried out at arbitrary temperature and time. Usually, it is dried at 50 to 120 ° C for 1 to 10 minutes to sufficiently remove the contained organic solvent, and then baked at 150 to 300 ° C for 5 to 120 minutes. The thickness of the coated film after firing is not particularly limited, but if it is too thin, the reliability of the liquid crystal display element may deteriorate. Therefore, it is 5 to 300 nm, preferably 10 to 200 nm.

Examples of a method for aligning the obtained liquid crystal alignment film include a rubbing method and an optical alignment treatment method.

[Liquid crystal display element]

The liquid crystal display element of the present invention is obtained by obtaining the substrate on which the liquid crystal alignment film is formed from the liquid crystal aligning agent of the present invention by the above-mentioned technique, performing orientation treatment, and then manufacturing a liquid crystal cell by a known method to obtain a liquid crystal display element .

The manufacturing method of the liquid crystal cell is not particularly limited. For example, a pair of substrates on which a liquid crystal alignment film is formed is preferably 1 to 30 占 퐉, more preferably 2 to 10 占 퐉 A spacer is interposed therebetween, the periphery is fixed with a sealant, and a liquid crystal is injected and sealed. The method of enclosing the liquid crystal is not particularly limited, and examples thereof include a vacuum method in which a liquid crystal cell is made in a reduced pressure and a liquid crystal is injected, and a dropping method in which liquid crystal is dropped and then encapsulation is performed.

Example

The abbreviations and structures of the compounds used in this Synthesis Example are shown below.

DMT-MM: 4- (4,6-dimethoxy-1,3,5-triazin-2-yl) -4-methylmorpholinium chloride

CBDE: 2,4-bis (methoxycarbonyl) cyclobutane-1,3-dicarboxylic acid

PMDE: 2,5-bis (methoxycarbonyl) benzene-1,4-dicarboxylic acid

CBDA: 1,2,3,4-Cyclobutane tetracarboxylic acid dianhydride

PMDA: pyromellitic acid dianhydride

DDE: 4,4'-diaminodiphenyl ether

DA-3MG: 1,3-bis (4-aminophenoxy) propane

DA-5MG: 1,5-bis (4-aminophenoxy) pentane

BAPU: 1,3-bis (4-aminophenethyl) urea

Me-DADPA: 4,4'-diaminodiphenylmethylamine

(31)

The measurement methods of viscosity, solid content concentration, and average surface roughness are shown below.

[Viscosity]

In the synthesis example, the viscosity of the polyamic acid solution or the polyamic acid ester solution was 1.1 ml of a sample amount, the cone TE-1 (1 ° 34 ', R24), and the viscosity of the solution was measured using an E-type viscometer TVE- The temperature was measured at 25 캜.

[Solid content concentration]

In the synthesis examples, the solid content concentration of the polyamic acid solution or the polyamic acid ester solution was calculated in the following manner.

About 1.1 g of the solution was weighed and placed in an aluminum cup No. 2 (manufactured by Asuzon Co., Ltd.) with a handle, heated at 200 ° C for 2 hours with an oven DNF400 (manufactured by Yamato), left at room temperature for 5 minutes, The weight of the remaining solid was weighed. The solid content concentration was calculated from the weight of the solid content and the value of the original solution weight.

[Average surface roughness]

In the Examples and Comparative Examples, the average surface roughness of the polyimide film was measured as follows.

The shape image measurement was performed in Dynamic Force Mode (DFM) using an L-trace device manufactured by S-Ai Nano Technology. The SI-DF40 was used for the cantilever, and the shape image obtained under the measurement conditions shown below was firstly corrected, and then the value of the average surface roughness was calculated.

Scanning Area: 10 占 퐉 占 10 占 퐉

Amplitude decay rate: -0.110 to -0.120

I gain: 0.0444

P gain: 0.0488

A gain: 5

S gain: 5

Scanning frequency: 1.50 Hz

(Synthesis Example 1)

8.47 g (30 mmol) of PMDE and 17.2 g (66 mmol) of CBDE were weighed and placed in a 1 L separable flask equipped with a stirrer, 684 g of N-methyl-2-pyrrolidone was added, And dissolved by stirring. Subsequently, 5.06 g (50 mmol) of triethylamine and 25.8 g (100 mmol) of DA-3MG were added and dissolved by stirring. While stirring this solution, 83.0 g (300 mmol) of DMT-MM (15 ± 2 wt% hydrate) was added, and further 122 g of N-methyl-2-pyrrolidone was added. The mixture was stirred at room temperature for 5 hours To obtain a solution of polyamic acid ester. The viscosity of this polyamic acid ester solution at 25 캜 was 32.3 mPa..

This polyamic acid ester solution was poured into methanol (5676 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at a temperature of 100 ° C to obtain a polyamic acid ester powder.

4.03 g of the polyamic acid ester powder was weighed into a 100 ml (milliliter) Erlenmeyer flask containing an agitator, and 29.6 g of N-methyl-2-pyrrolidone was added and dissolved by stirring at room temperature for 18 hours. Then, 10.4 g of N-methyl-2-pyrrolidone and 18.9 g of butyl cellosolve were added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid concentration of 5.9% by mass.

(Synthesis Example 2)

2.68 g (9.5 mmol) of PMDE was weighed and placed in a 200 ml four-necked flask equipped with a stirrer, and 70 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Subsequently, 0.51 g (5 mmol) of triethylamine and 2.58 g (10 mmol) of DA-3MG were added and dissolved by stirring. While stirring the solution, 9.96 g (36 mmol) of DMT-MM (15 ± 2 wt% hydrate) was added, and further 13 g of N-methyl-2-pyrrolidone was added and stirred at room temperature for 4 hours To obtain a solution of polyamic acid ester. The viscosity of this polyamic acid ester solution at 25 캜 was 35.9 mPa..

This polyamic acid ester solution was poured into methanol (589 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at a temperature of 100 ° C to obtain a polyamic acid ester powder.

2.23 g of the polyamic acid ester powder was weighed into a 50 ml Erlenmeyer flask containing 25 g of an agitator, and 25.2 g of N-methyl-2-pyrrolidone was added and dissolved by stirring at room temperature for 10 hours. Then, 6.86 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 5.7% by mass.

(Synthesis Example 3)

48.9 g (188 mmol) of CBDE was weighed and placed in a 2 L separable flask equipped with a stirrer, 1418 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Subsequently, 10.1 g (100 mmol) of triethylamine and 40.1 g (140 mmol) of DA-5MG and 17.9 g (60 mmol) of BAPU were added and dissolved by stirring. While stirring this solution, 155 g (560 mmol) of DMT-MM (15 ± 2 wt% hydrate) was added, and further 254 g of N-methyl-2-pyrrolidone was added and stirred at room temperature for 16 hours To obtain a solution of polyamic acid ester. The viscosity of this polyamic acid ester solution at 25 캜 was 25.6 mPa..

This polyamic acid ester solution was poured into methanol (11681 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at a temperature of 100 ° C to obtain a polyamic acid ester powder.

22.4 g of the polyamic acid ester powder was weighed and placed in a 500 ml Erlenmeyer flask. Then, 201 g of N-methyl-2-pyrrolidone was added and dissolved by stirring at room temperature for 18 hours. Subsequently, 11.9 g of N-methyl-2-pyrrolidone and 100 g of butyl cellosolve were added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 6.0% by mass.

(Synthesis Example 4)

In a 500 ml four-necked flask equipped with a stirrer, 11.5 g (44.2 mmol) of CBDE was weighed, and 278 g of N-methyl-2-pyrrolidone was added and dissolved by stirring. Subsequently, 2.38 g (23.5 mmol) of triethylamine and 9.41 g (47 mmol) of DDE were added and dissolved by stirring. While this solution was stirred, 39.0 g (141 mmol) of DMT-MM (15 ± 2 wt% hydrate) was added, and further 50 g of N-methyl-2-pyrrolidone was added and stirred at room temperature for 3 hours To obtain a solution of polyamic acid ester. The viscosity of this polyamic acid ester solution at 25 캜 was 17.8 mPa..

This polyamic acid ester solution was poured into methanol (2339 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at a temperature of 100 ° C to obtain a polyamic acid ester powder.

1.60 g of the polyamic acid ester powder was weighed into a 50 ml Erlenmeyer flask containing a stirrer, and 11.7 g of N-methyl-2-pyrrolidone was added thereto and dissolved by stirring at room temperature for 8 hours. Then, 6.82 g of N-methyl-2-pyrrolidone and 4.75 g of butyl cellosolve were added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid content concentration of 6.1% by mass.

(Synthesis Example 5)

2.54 g (9 mmol) of PMDE and 5.07 g (19.5 mmol) of CBDE were weighed in a 300 ml four-necked flask equipped with a stirrer, 181 g of N-methyl-2-pyrrolidone was added, . Subsequently, 1.52 g (15 mmol) of triethylamine and 6.01 g (30 mmol) of DDE were added and dissolved by stirring. While this solution was stirred, 24.9 g (90 mmol) of DMT-MM (15 ± 2 wt% hydrate) was added, and further 32 g of N-methyl-2-pyrrolidone was added and stirred at room temperature for 5 hours To obtain a solution of polyamic acid ester. The viscosity of this polyamic acid ester solution at 25 캜 was 25.8 mPa..

This polyamic acid ester solution was poured into methanol (1520 g), and the resulting precipitate was separated by filtration. The precipitate was washed with methanol and dried under reduced pressure at a temperature of 100 ° C to obtain a polyamic acid ester powder.

This polyamic acid ester powder (4.98 g) was weighed into a 100 ml Erlenmeyer flask containing an agitator, and 53.1 g of N-methyl-2-pyrrolidone was added and dissolved by stirring at room temperature for 8 hours. Subsequently, 24.9 g of butyl cellosolve was added and stirred for 2 hours to obtain a polyamic acid ester solution having a solid concentration of 5.8 mass%.

(Synthesis Example 6)

5.94 g (23 mmol) of DA-3MG was weighed and placed in a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 65 g of N-methyl-2-pyrrolidone was added, And dissolved by stirring. To this diamine solution, 4.35 g (22.2 mmol) of CBDA was added while stirring, and N-methyl-2-pyrrolidone was further added thereto so as to have a solid content concentration of 10% by mass and stirred at room temperature for 3 hours To obtain a solution of polyamic acid. The viscosity of this polyamic acid solution at 25 캜 was 152 mPa s.

18.7 g of the polyamic acid solution was weighed into a 50 ml Erlenmeyer flask containing an agitator, 2.30 g of N-methyl-2-pyrrolidone and 9.01 g of butyl cellosolve were added and stirred for 2 hours to obtain a solid concentration of 6.0 Mass% of a polyamic acid solution was obtained.

(Synthesis Example 7)

4.75 g (18.4 mmol) of DA-3MG and 0.98 g (4.6 mmol) of Me-DADPA were weighed and placed in a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 63 g of lauridone was added and dissolved by stirring while nitrogen was being supplied. To this diamine solution, 4.35 g (22.2 mmol) of CBDA was added while stirring, and N-methyl-2-pyrrolidone was further added thereto so as to have a solid content concentration of 10% by mass and stirred at room temperature for 5 hours To obtain a solution of polyamic acid. The viscosity of the polyamic acid solution at 25 캜 was 145 mPa..

18.6 g of the polyamic acid solution was weighed into a 50 ml Erlenmeyer flask containing an agitator, 2.60 g of N-methyl-2-pyrrolidone and 9.09 g of butyl cellosolve were added and stirred for 2 hours to obtain a solid content concentration of 6.1 Mass% of a polyamic acid solution was obtained.

(Synthesis Example 8)

3.56 g (13.8 mmol) of DA-3MG and 1.96 g (9.2 mmol) of Me-DADPA were weighed and placed in a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 62 g of lauridone was added and dissolved by stirring while nitrogen was being fed. To this diamine solution, 4.35 g (22.2 mmol) of CBDA was added while stirring, and N-methyl-2-pyrrolidone was further added thereto so as to have a solid content concentration of 10% by mass and stirred at room temperature for 6.5 hours To obtain a solution of polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25 캜 was 137 mPa s.

To a 50 ml Erlenmeyer flask containing 18.5 g of the polyamic acid solution, 2.95 g of N-methyl-2-pyrrolidone and 9.20 g of butyl cellosolve were added and stirred for 2 hours to obtain a solid content concentration of 6.1 Mass% of a polyamic acid solution was obtained.

(Synthesis Example 9)

33.6 g (130 mmol) of DA-3MG was weighed and placed in a 1 L separable flask equipped with a stirrer and a nitrogen inlet tube, 379 g of N-methyl-2-pyrrolidone was added, And dissolved by stirring. 26.7 g (122 mmol) of PMDA was added while stirring the diamine solution, N-methyl-2-pyrrolidone was further added thereto so as to have a solid content concentration of 10 mass%, and the mixture was stirred at room temperature for 6 hours To obtain a solution of polyamic acid. The viscosity of the polyamic acid solution at 25 캜 was 162 mPa..

32.1 g of the polyamic acid solution was weighed into a 100 ml Erlenmeyer flask containing an agitator, and 6.29 g of N-methyl-2-pyrrolidone and 9.60 g of butyl cellosolve were added and stirred for 2 hours to obtain a solid content concentration of 5.9 Mass% of a polyamic acid solution was obtained.

(Synthesis Example 10)

23.1 g (80.5 mmol) of DA-5MG and 10.3 g (34.5 mmol) of BAPU were weighed and placed in a 500 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, and N-methyl- 342 g was added and dissolved by stirring while nitrogen was being supplied. 21.0 g (107 mmol) of CBDA was added while stirring the diamine solution, and N-methyl-2-pyrrolidone was further added thereto so that the solid concentration became 10% by mass, and the mixture was stirred at room temperature for 2.5 hours To obtain a solution of polyamic acid. The viscosity of this polyamic acid solution at 25 캜 was 117 mPa..

120 g of the polyamic acid solution was weighed into a 300 ml Erlenmeyer flask containing stirrer and 14.1 g of N-methyl-2-pyrrolidone and 57.5 g of butyl cellosolve were added and stirred for 2 hours to obtain a solid concentration of 6.0 Mass% of a polyamic acid solution was obtained.

(Synthesis Example 11)

12.0 g (60 mmol) of DDE was weighed in a 200 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 125 g of N-methyl-2-pyrrolidone was added, . While stirring the diamine solution, 12.4 g (57 mmol) of PMDA was added, N-methyl-2-pyrrolidone was further added thereto so as to have a solid content concentration of 12 mass%, and the mixture was stirred at room temperature for 2 hours To obtain a solution of polyamic acid. The viscosity of this polyamic acid solution at 25 캜 was 356 mPa..

26.8 g of N-methyl-2-pyrrolidone and 19.5 g of butyl cellosolve were added, and the mixture was stirred for 2 hours to obtain a solid content concentration of 6.1 Mass% of a polyamic acid solution was obtained.

(Synthesis Example 12)

To a 100 ml four-necked flask equipped with a stirrer and a nitrogen-introducing tube, 6.01 g (30 mmol) of DDE was weighed, and 55 g of N-methyl-2-pyrrolidone was added thereto. . 5.71 g (29.1 mmol) of CBDA was added while stirring the diamine solution, N-methyl-2-pyrrolidone was further added thereto so as to have a solid content concentration of 12 mass%, and the mixture was stirred at room temperature for 4.5 hours To obtain a solution of polyamic acid. The viscosity of the polyamic acid solution at 25 캜 was 358 mPa..

15.5 g of the polyamic acid solution was weighed into a 50 ml Erlenmeyer flask containing an agitator, and 9.89 g of N-methyl-2-pyrrolidone and 6.36 g of butyl cellosolve were added and stirred for 2 hours to obtain a solid concentration of 6.0 Mass% of a polyamic acid solution was obtained.

(Comparative Synthesis Example 1)

2.48 g (9.6 mmol) of DA-3MG and 3.07 g (14.4 mmol) of Me-DADPA were weighed and placed in a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 63 g of lauridone was added and dissolved by stirring while nitrogen was being supplied. To this diamine solution, 4.54 g (23.2 mmol) of CBDA was added while stirring, and N-methyl-2-pyrrolidone was further added thereto so as to have a solid content concentration of 10 mass%, and the mixture was stirred at room temperature for 6.5 hours To obtain a solution of polyamic acid. The viscosity of the polyamic acid solution at 25 캜 was 158 mPa..

To a 50 ml Erlenmeyer flask containing 18.7 g of the polyamic acid solution was weighed, and 3.14 g of N-methyl-2-pyrrolidone and 9.38 g of butyl cellosolve were added and stirred for 2 hours to obtain a solid concentration of 6.0 Mass% of a polyamic acid solution was obtained.

(Comparative Synthesis Example 2)

1.24 g (4.8 mmol) of DA-3MG and 4.09 g (19.2 mmol) of Me-DADPA were weighed and placed in a 100 ml four-necked flask equipped with a stirrer and a nitrogen inlet tube, 61 g of lauridone was added and dissolved by stirring while nitrogen was being supplied. To this diamine solution, 4.54 g (23.2 mmol) of CBDA was added while stirring, and N-methyl-2-pyrrolidone was further added thereto so as to have a solid content concentration of 10 mass%, and the mixture was stirred at room temperature for 6.5 hours To obtain a solution of polyamic acid. The viscosity of this polyamic acid solution at a temperature of 25 캜 was 140 mPa..

18.2 g of the polyamic acid solution was weighed into a 50 ml Erlenmeyer flask containing an agitator, 3.18 g of N-methyl-2-pyrrolidone and 9.15 g of butyl cellosolve were added and stirred for 2 hours to obtain a solid content concentration of 6.1 Mass% of a polyamic acid solution was obtained.

&Lt; Example 1 >

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 1 and the polyamic acid solution obtained in Synthesis Example 6 at a solid weight ratio of 50:50 was filtered with a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.32 nm.

Here, CBDA and CBDE, which are tetracarboxylic acid derivatives, use CBDA having 100% of polyamic acid (Synthesis Example 6) and having the same cyclobutane moiety, while polyamic acid ester (Synthesis Example 1) (68.8 = 66 / (30 + 66)%), the agreement ratio of X ₁ and X ₂ was 68.8%.

In the polyamic acid ester (Synthesis Example 1) and polyamic acid (Synthesis Example 6), DA-3MG was used as the diamine, so that the agreement ratio of Y ₁ and Y ₂ was 100%.

The concordance of X _1, X ₂ and Y ₁ and Y ₂ are, in the embodiment 2-9, and Comparative Examples 1 and 2 shown in Table 1, and the same is calculated.

&Lt; Example 2 >

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 1 and the polyamic acid solution obtained in Synthesis Example 7 at a solid weight ratio of 50:50 was filtered with a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.61 nm.

&Lt; Example 3 >

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 1 and the polyamic acid solution obtained in Synthesis Example 8 at a solid weight ratio of 50:50 was filtered with a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.85 nm.

<Example 4>

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 2 and the polyamic acid solution obtained in Synthesis Example 9 at a solid weight ratio of 50:50 was filtered with a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.40 nm.

&Lt; Example 5 >

A solution prepared by mixing the polyamic acid ester solution obtained in Synthesis Example 3 and the polyamic acid solution obtained in Synthesis Example 10 at a solid weight ratio of 30:70 was filtered with a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.42 nm.

&Lt; Example 6 >

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 4 and the polyamic acid solution obtained in Synthesis Example 11 at a solid weight ratio of 50:50 was filtered with a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.24 nm.

&Lt; Example 7 >

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 5 and the polyamic acid solution obtained in Synthesis Example 11 at a solid weight ratio of 50:50 was filtered through a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.24 nm.

&Lt; Example 8 >

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 5 and the polyamic acid solution obtained in Synthesis Example 12 at a solid weight ratio of 50:50 was filtered with a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.38 nm.

&Lt; Example 9 >

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 2 and the polyamic acid solution obtained in Synthesis Example 6 at a solid weight ratio of 50:50 was filtered with a filter having a size of 1.0 탆 and then spin-coated on a glass substrate having a transparent electrode , Dried for 5 minutes on a hot plate at a temperature of 80 占 폚, and fired at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 0.74 nm.

&Lt; Comparative Example 1 &

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 1 and the polyamic acid solution obtained in Comparative Synthesis Example 1 at a solid weight ratio of 50:50 was filtered through a filter having a size of 1.0 탆 and a spin coat , Followed by drying for 5 minutes on a hot plate at a temperature of 80 占 폚 and firing at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 1.13 nm.

&Lt; Comparative Example 2 &

A solution obtained by mixing the polyamic acid ester solution obtained in Synthesis Example 1 and the polyamic acid solution obtained in Comparative Synthesis Example 2 at a solid weight ratio of 50:50 was filtered with a filter having a size of 1.0 탆 and then a spin coat , Followed by drying for 5 minutes on a hot plate at a temperature of 80 占 폚 and firing at a temperature of 230 占 폚 for 30 minutes to obtain a polyimide film having a thickness of 100 nm. The average surface roughness of this polyimide film was measured and found to be 1.20 nm.

The effect of the present invention was confirmed with respect to the comparative example in that the value of the average surface roughness in this measurement condition is 1 nm or less in a general single component polyimide film.

Industrial availability

The liquid crystal aligning agent of the present invention is capable of reducing the fine unevenness on the surface of the obtained liquid crystal alignment film to improve the liquid crystal alignment property and to improve the electrical retention such as voltage retention rate, ion density, residual image due to alternating current, The characteristics are also improved. As a result, it is widely useful for TN devices, STN devices, TFT liquid crystal devices, and vertically aligned liquid crystal display devices.

The entire contents of the specification, claims and abstract of Japanese Patent Application No. 2011-016979 filed on January 28, 2011 are hereby incorporated herein by reference as the disclosure of the specification of the present invention.

Claims (7)

1. A polyimide resin composition comprising a polyamic acid ester having a repeating unit represented by the following formula (1) and a polyamic acid having a repeating unit represented by the following formula (2), wherein the divalent organic group (Y ₁ ) Wherein at least 60 mol% of the divalent organic group (Y ₂ ) in the mixed acid has the same structure.

(In the formulas (1) and (2), X ₁ and X ₂ are each independently a tetravalent organic group, Y ₁ and Y ₂ are each independently a divalent organic group, and A ₁ and A ₂ are Independently, a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or an alkynyl group having 2 to 10 carbon atoms, which may have a substituent, and R ₁ is a methyl group) The method according to claim 1,
Wherein the content of the polyamic acid ester and the content of the polyamic acid in the mass ratio of (polyamic acid ester content / polyamic acid) is 1/9 to 9/1. The method according to claim 1,
Wherein the tetravalent organic group (X ₁ ) of the polyamic acid ester and the tetravalent organic group (X ₂ ) possessed by the polyamic acid have an identical structure of at least 60 mol%. The method according to claim 1,
Further comprising an organic solvent, wherein the total content of the polyamic acid ester and the polyamic acid is 0.5 to 15 mass% with respect to the organic solvent. The method according to claim 1,
X ₁ and X ₂ in the formulas (1) and (2) are each independently at least one selected from the structures represented by the following formulas.
(2)

The method according to claim 1,
Formulas (1) and (2), Y _1, Y ₂ are, each independently, a liquid crystal orientation at least one selected from structures represented by any of formulas to according to.
(3)

A liquid crystal alignment film obtained by applying and firing the liquid crystal aligning agent according to any one of claims 1 to 6.