JP2015000983A - Siloxane diacid anhydride, polymer, liquid crystal aligning agent, liquid crystal alignment film and liquid crystal display - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a siloxane diacid anhydride having excellent solubility and advantageous for the preparation of a polymer, a liquid crystal aligning agent and a liquid crystal alignment film.SOLUTION: A siloxane diacid anhydride has a structure represented by the following formula (I) where Gis formula (II) or formula (III).

Description

  The present invention relates to a dianhydride, a polymer, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display device, and in particular, a siloxane dianhydride, a polymer prepared using the siloxane dianhydride, and a liquid crystal alignment. The present invention relates to an agent, a liquid crystal alignment film, and a liquid crystal display element including the liquid crystal alignment film.

  Since the liquid crystal display device has characteristics such as lightness, thinness, power saving, and high image quality, it has already become more and more mainstream in the market and is widely applied to various electronic products. In a typical process for producing a liquid crystal alignment film, the solubility of the liquid crystal aligning agent is poor, and when the coating process is not being performed or when the coating apparatus is not used, the liquid crystal aligning agent contacts the water vapor in the air to precipitate or level the solute. In addition to degrading the characteristics of the liquid crystal display device, it may always waste material and increase the environmental load.

  On the other hand, the liquid crystal aligning agent is generally often obtained by blending polymers each having a high surface energy and a low surface energy, and effectively phase-separates it by a subsequent high-temperature processing process. By depositing a low surface energy polymer in the upper layer in contact with the liquid crystal molecules during film formation, the liquid crystal molecules can maintain a stable orientation, and at the same time, a high surface energy polymer ( That is, the adhesion property of the polymer is improved by moving a compound having many carboxyl groups) to the lower glass substrate. However, once the processing temperature is not sufficiently high, after the liquid crystal aligning agent is formed, not only the adhesion is bad, but also the orientation is affected. A high processing temperature means that the amount of carbon dioxide emission is relatively high and the consumption of electric power and heat is also increased, which prevents the liquid crystal display device from entering the green industry.

  Therefore, this invention provides the siloxane dianhydride which is excellent in solubility and advantageous for preparation of a polymer, a liquid crystal aligning agent, and a liquid crystal aligning film.

  Next, when the present invention is not completely cyclized, the solubility is excellent, and when fully cyclized and baked, the adhesion and mechanical properties are improved, and the liquid crystal aligning agent and the liquid crystal aligning film are improved. Provided is a polymer obtained by polymerizing the siloxane dianhydride and diamine, which is advantageous for preparation.

  The present invention also provides a liquid crystal aligning agent comprising the polymer, which has excellent solubility, is advantageous for coating, has a low required processing temperature, and is advantageous for energy saving and reduction of environmental load.

  The present invention also provides a liquid crystal alignment film formed of the liquid crystal alignment agent, which has excellent vertical alignment properties and adhesion properties, and improves the reliability of the product.

  Finally, the present invention provides a liquid crystal display element including the liquid crystal alignment film and having excellent product reliability.

Ｇ₁が式（ＩＩ）又は式（ＩＩＩ）であり、Ｒ₁〜Ｒ₆の少なくとも２つがフェニル基であり又は少なくとも１つが‐ＣＨ₂ＣＨ₂ＣＦ₃であり、残りがそれぞれ独立に１価の有機基である。ｎが０〜３０の整数であり且つｎが０である場合、Ｒ₁、Ｒ₂、Ｒ₅及びＲ₆の少なくとも２つがフェニル基であり又は少なくとも１つが‐ＣＨ₂ＣＨ₂ＣＦ₃である。 The siloxane dianhydride according to one embodiment of the present invention has a structure represented by the formula (I).

G ₁ is formula (II) or formula (III), at least two of R _{1 to} R ₆ are phenyl groups, or at least one is —CH ₂ CH ₂ CF ₃ , and the rest are each independently monovalent Organic group. When n is an integer of 0 to 30 and n is 0, at least two of R ₁ , R ₂ , R ₅ and R ₆ are phenyl groups, or at least one is —CH ₂ CH ₂ CF ₃ .

In the siloxane dianhydride having the structure represented by the formula (I), at least two of R _{1 to} R ₆ are phenyl groups, or at least one of them is —CH ₂ CH ₂ CF ₃ , and the rest each independently has 1 carbon atom. It may be an alkyl group of ˜5.

The polymer according to the present invention is obtained by polymerizing a reaction product containing a siloxane dianhydride having the structure represented by the above formula (I) and a diamine, and includes a polyamic acid, a polyimide, or a polyamic acid-polyimide copolymer. . At least two of R _{1 to} R ₆ are phenyl groups, or at least one is —CH ₂ CH ₂ CF ₃ , the rest are each independently a monovalent organic group, and n is an integer of 0 to 30. When n is 0, at least two of R ₁ , R ₂ , R ₅ and R ₆ are phenyl groups or at least one is —CH ₂ CH ₂ CF ₃ .

In the siloxane dianhydride having the structure represented by the above formula (I), at least two of R _{1 to} R ₆ are phenyl groups, or at least one of them is —CH ₂ CH ₂ CF ₃ , and the remainder is independently carbon number. It may be 1 to 5 alkyl groups.

N of the siloxane dianhydride having the structure shown in the above formula (I) may be 1, R ₃ and R ₄ may be a phenyl group, and R ₁ , R ₂ , R ₅ and R ₆ are each Independently, it may be an alkyl group having 1 carbon atom.

In the siloxane dianhydride having the structure represented by the above formula (I), n may be 4, R ₃ may be —CH ₂ CH ₂ CF ₃ , and R ₁ , R ₂ , R ₄ , R ₅ And R ₆ may be each independently a C 1 alkyl group.

  The reactant may further contain other dianhydride, and the content of siloxane dianhydride is 10 mol% to 99 mol% of the total amount of siloxane dianhydride and other dianhydride. It's okay.

The liquid crystal aligning agent according to the present invention is a polyamic acid, a polyimide or a polyamic acid-polyimide copolymer obtained by polymerizing a reaction product containing a siloxane dianhydride having a structure represented by the above formula (I) and a diamine. A polymer containing At least two of R _{1 to} R ₆ are phenyl groups, or at least one is —CH ₂ CH ₂ CF ₃ , the rest are each independently a monovalent organic group, and n is an integer of 0 to 30. When n is 0, at least two of R ₁ , R ₂ , R ₅ and R ₆ are phenyl groups or at least one is —CH ₂ CH ₂ CF ₃ .

In the siloxane dianhydride having the structure represented by the above formula (I), at least two of R _{1 to} R ₆ are phenyl groups, or at least one of them is —CH ₂ CH ₂ CF ₃ , and the remainder is independently carbon number. It may be 1 to 5 alkyl groups.

N of the siloxane dianhydride having the structure shown in the above formula (I) may be 1, R ₃ and R ₄ may be a phenyl group, and R ₁ , R ₂ , R ₅ and R ₆ are each Independently, it may be an alkyl group having 1 carbon atom.

In the siloxane dianhydride having the structure represented by the above formula (I), n may be 4, R ₃ may be —CH ₂ CH ₂ CF ₃ , and R ₁ , R ₂ , R ₄ , R ₅ And R ₆ may be each independently a C 1 alkyl group.

  The reactant may further contain other dianhydride, and the content of siloxane dianhydride is 10 mol% to 99 mol%, 30 mol of the total amount of siloxane dianhydride and other dianhydride. % To 99 mol% or 70 mol% to 99 mol%.

The liquid crystal alignment film according to the present invention is formed of the liquid crystal alignment agent.
The liquid crystal display element according to the present invention includes the liquid crystal alignment film.

¹ is a ¹ H NMR spectrum of a siloxane dianhydride according to a first embodiment of the present invention. 3 is a ¹ H NMR spectrum of a siloxane dianhydride according to a second embodiment of the present invention.

  The present invention provides a siloxane dianhydride and a series of polymers made of siloxane dianhydride, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display device including a liquid crystal alignment film.

Ｇ₁が式（ＩＩ）又は式（ＩＩＩ）であり、Ｒ₁〜Ｒ₆の少なくとも２つがフェニル基であり又は少なくとも１つが‐ＣＨ₂ＣＨ₂ＣＦ₃であり、残りがそれぞれ独立に１価の有機基であり、好ましくは、それぞれ独立に炭素数１〜５のアルキル基である。一方、ｎが０〜３０の整数であり且つｎが０である場合、Ｒ₁、Ｒ₂、Ｒ₅及びＲ₆の少なくとも２つがフェニル基であり又は少なくとも１つが‐ＣＨ₂ＣＨ₂ＣＦ₃である。また、好ましくは、ｎが１〜１５の整数であり、より好ましくは、１〜４の整数である。 (Siloxane dianhydride)
The siloxane dianhydride according to the present invention has a structure represented by the formula (I),

G ₁ is formula (II) or formula (III), at least two of R _{1 to} R ₆ are phenyl groups, or at least one is —CH ₂ CH ₂ CF ₃ , and the rest are each independently monovalent An organic group, preferably each independently an alkyl group having 1 to 5 carbon atoms. On the other hand, when n is an integer of 0 to 30 and n is 0, at least two of R ₁ , R ₂ , R ₅ and R ₆ are phenyl groups, or at least one is —CH ₂ CH ₂ CF ₃ . is there. Moreover, n is preferably an integer of 1 to 15, more preferably an integer of 1 to 4.

  The siloxane dianhydride having the structure shown in the above formula (I) can be prepared by a typical hydrosilylation reaction. More specifically, it is obtained by dissolving an acid anhydride precursor in a solvent and subjecting it to a hydrosilylation reaction with a siloxane precursor by the catalytic action of a transition metal. Purity can be improved. The reaction temperature is usually 40 ° C to 110 ° C, preferably 90 ° C to 110 ° C, and the reaction time is usually 2 hours to 30 hours, preferably 8 hours to 12 hours. The solvent is, for example, a conventional solvent for typical hydrosilylation reaction, preferably ethyl ether, tetrahydrofuran (THF) or ethyl acetate, more preferably toluene. Examples of the catalyst include the famous Speier catalyst, Karstedt catalyst (for example, commercially available products such as PC072, PC075, United Chemical Tech., Inc.), Ashby catalyst (for example, commercially available products such as PC085, United Chemical Tech., Inc.). .), A catalyst containing a transition metal platinum, such as a Lamoreaux catalyst.

The siloxane precursor for preparing the siloxane dianhydride having the structure represented by the above formula (I) may be selected from the compounds shown in Table 1 below, and the acid anhydride precursor is It may be selected from the compounds shown in Table 2. However, the siloxane precursor and the acid anhydride precursor are not limited to the exemplified compounds, and the siloxane precursor has at least two phenyl groups or at least one —CH ₂ CH ₂ CF ₃ group, The acid anhydride precursor may contain a norbornene structure or a tetrahydrophthalic anhydride structure.

(Polymer)
The polymer according to the present invention is obtained by a polymerization reaction between a reactant and a diamine. More specifically, the reaction product is obtained by dissolving the reactant in a solvent and adding a diamine to undergo a polymerization reaction, and the solid content of the polymer may be adjusted with the same solvent as necessary in the reaction process. . The reaction temperature is usually 20 ° C. to 180 ° C., preferably 60 ° C. to 110 ° C., and the reaction time is usually 2 hours to 24 hours, preferably 4 hours to 12 hours, more preferably 8 hours. It's time. As solid content, it is 10 wt%-50 wt% normally, Preferably it is 10 wt%-30 wt%, More preferably, it is 15 wt%.

The reactant includes a siloxane dianhydride having a structure represented by the above formula (I), and the siloxane dianhydride having a structure represented by the above formula (I) preferably has n of 1, R ₃ And R ₄ is a phenyl group, and R ₁ , R ₂ , R ₅ and R ₆ are each independently an alkyl group having 1 carbon atom, or n is 4, and R ₃ is —CH ₂ CH ₂ CF ₃ and R ₁ , R ₂ , R ₄ , R ₅ and R ₆ are each independently an alkyl group having 1 carbon atom. Examples of the solvent include N-methylpyrrolidone (NMP), N, N-dimethylformamide (DMF), N, N-dimethylacetamide (DMAc), dimethylsulfoxide DM. N-methylcaprolactam, isopropanol (IPA) and the like.

  The reactant may be a dianhydride compound, a mixture of two or more dianhydride compounds, for example, a siloxane dianhydride having the structure shown in the above formula (I) and other dianhydride compounds. It may be a mixture of dianhydrides. The diamine may be a diamine compound or a mixture of two or more diamine compounds. The polymer may contain a polyamic acid, a polyimide or a polyamic acid-polyimide copolymer depending on the degree of polymerization and dehydration ring closure in the polymerization reaction process. In other words, the polymerization reaction may include a subsequent dehydration ring-closing reaction other than the polymerization of dianhydride and diamine.

  More specifically, preferably, the reactant is a mixture containing a siloxane dianhydride having a structure represented by the above formula (I) and another dianhydride, and the former content is a total amount of both Of 10 mol% to 99 mol%, preferably 30 mol% to 99 mol%, more preferably 70 mol% to 99 mol%. Preferably, the diamine is a mixture in which two or more diamine compounds are mixed.

  Other dianhydrides include, for example, 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), pyromellitic dianhydride (pyromellitic dianhydride). PMDA), 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA), 3,4-dicarboxy-1,2,4,3 ′, 4,4′-biphenyltetracarboxylic dianhydride (BPDA); 3,4-tetrahydro-1-naphthalene succinic anhydride (3,4-dicarboxy-1,2,3,4-tetrahydro-1-naphthalene succinichydride; TDA), Rikacid BT-100 (1,2,3,4) Butanetetracarboxylic dianhydride (1,2,3,4-butanetetracarboxylic dianhydride)), Rikacid TMEG-100 (ethylene glycol bis (trimellitic anhydride) or 5) -1H-pyrano [3,4-d] oxepin-1,3,6,8 (4H) -tetraone, tetrahydro (TCA-AH, chemical registration number CAS: 6053-46-9), etc., and diamine Examples of the compound include 5 (6) -amino-1,3,3-trimethyl-1- (4-aminophenyl) -indane (TMDA, chemical registration number CAS: 54628-89-6) or 4 ′. -Propylbi (cyclohexane) -4-yl-3,5 Such as, but not limited to, diamino-2-methylbenzoate (3CC, Daxin Materials Co., Ltd), and other dianhydrides and diamine compounds may synthesize any known polymer. For example, a conventional dianhydride and a diamine compound may be used.

(Liquid crystal aligning agent)
The liquid crystal aligning agent by this invention contains the polymer by the said this invention. Preferably, the liquid crystal aligning agent includes the polymer according to the present invention and another polymer, and the other polymer is obtained by polymerizing the other dianhydride and the diamine. More specifically, the liquid crystal aligning agent uniformly mixes the polymer according to the present invention and another polymer, and adjusts the solid content of the liquid crystal aligning agent with a solvent as necessary. The mixing temperature is usually 20 ° C. to 60 ° C., preferably 25 ° C. to 40 ° C., and the solid content of the liquid crystal aligning agent is usually 3.0 wt% to 8.0 wt%, preferably 3 It is 0.5 wt% to 6.5 wt%, more preferably 6.5 wt%. The solvent is, for example, a mixture of NMP and diethylene glycol monobutyl ether (BC), and the weight ratio of the two is preferably 1: 1. The solvent to be applied is not limited to these, and may be a conventional solvent for adjusting the solid content of any known liquid crystal aligning agent.

(Liquid crystal alignment film)
The liquid crystal alignment film according to the present invention is formed of the liquid crystal alignment agent according to the present invention. First, a liquid crystal aligning agent is apply | coated to a glass substrate, As an application method, it may be conventional application methods, such as roller application | coating, spin application | coating, or printing. Next, it heat-bakes and forms the liquid crystal aligning agent apply | coated to the glass substrate as a liquid crystal aligning film. The heating baking temperature is usually 180 ° C to 250 ° C, preferably 200 ° C to 230 ° C, more preferably 230 ° C, and the heating baking time is usually 20 minutes to 120 minutes, preferably 30 minutes. -60 minutes, more preferably 30 minutes. The thickness of the formed liquid crystal alignment film is usually 0.05 μm to 0.20 μm, preferably 0.06 μm to 0.15 μm, more preferably Is 0.12 μm.

(Liquid crystal display element)
The liquid crystal display element according to the present invention includes the liquid crystal alignment film according to the present invention. As an example of a method for producing a liquid crystal display element, first, a glass substrate on which two liquid crystal alignment films according to the present invention are formed is taken, then a sealing agent is applied to one glass substrate, and the other is taken. Spray spacers on glass substrate. Thereafter, the two glass substrates are combined such that the brushing directions of the films are perpendicular or parallel to each other. Finally, liquid crystal molecules are injected into the gap between the two glass substrates, and then the injection hole is sealed to complete.

  Hereinafter, the siloxane dianhydride and the series of polymers produced with the siloxane dianhydride according to the present invention, a liquid crystal alignment agent, a liquid crystal alignment film, and a liquid crystal display device including the liquid crystal alignment film will be further described.

(First embodiment: Siloxane dianhydride (I-1))
Siloxane dianhydride (I-1) can be obtained by the following reaction formula (1).

  First, 328.32 g of the acid anhydride precursor (2-1) was mixed with 330.47 g of toluene, and 1.0 g of PC085 catalyst (United Chemical Tech., Inc.) was added and stirred uniformly. Next, the temperature was raised to 110 ° C. and held for 8 hours, and then lowered to 90 ° C., 349.25 g of siloxane precursor (1-2) was added, and the temperature was held at 90 ° C. for 12 hours. Finally, toluene was discharged completely to obtain siloxane dianhydride (I-1), and the yield was 93%.

FIG. 1 is a ¹ H nuclear magnetic resonance (NMR) spectrum of siloxane dianhydride (I-1). According to this spectrum, siloxane dianhydride (I-1) was converted by the above preparation method. It was confirmed that it can be obtained. Further, the siloxane dianhydride (I-1) is a transparent solid at room temperature, and it can be measured by a differential scanning calorimeter (DSC) to have a melting point of 40 ° C. to 55 ° C. did it.

(Second embodiment: Siloxane dianhydride (I-2))
Siloxane dianhydride (I-2) can be obtained by the following reaction formula (2).

  First, 328.32 g of the acid anhydride precursor (2-1) was mixed with 50.07 g of toluene, 0.01 g of PC085 catalyst was added, and the mixture was stirred uniformly. Next, the temperature was raised to 110 ° C. and held for 8 hours, and then lowered to 90 ° C., 70.68 g of the siloxane precursor (1-7) was added, and the temperature was held at 90 ° C. for 12 hours. Finally, the toluene was completely discharged to obtain siloxane dianhydride (I-2), and the yield was 97%.

FIG. 2 is a ¹ H NMR spectrum of siloxane dianhydride (I-2). This spectrum confirms that siloxane dianhydride (I-2) can be obtained with the above preparation method. did it. Siloxane dianhydride (I-2) is a transparent liquid at room temperature.

  Table 3 shows the solubility of siloxane dianhydride (I-1) and siloxane dianhydride (I-2) in different solvents compared to other dianhydrides. As a test method for solubility, in a room temperature environment (about 25 ° C.), 0.5 g of dianhydride is taken, placed in 30 g of solvent and stirred for 30 minutes, and dianhydride is dissolved in various solvents. Was observed. The dissolution state is clear (dissolvable) as “+”, the suspension state (dissolvable) as “±”, and the precipitation state (dissolvable) as “−”. Indicated. Other dianhydrides for testing were CBDA, PMDA, BPDA, TDA, Rikacid BT-100 and Rikacid TMEG-100. Solvents include Equamide M100 (product name, idemitsu Kosan Co., Ltd, Japan), metacresol (m-cresol), THF, NMP, DMSO, DMF, DMAc, acetone (acetone), and propylene glycol methyl ether acetate (propylene). glycol monoethyl ether acetate (PGMEA).

  From Table 3, since siloxane dianhydride (I-1) and siloxane dianhydride (I-2) can exhibit better solubility characteristics than other dianhydrides, polyamides It turned out that it is advantageous to preparation of polymers, such as an acid or a polyimide, a liquid crystal aligning agent, and a liquid crystal aligning film.

(Third embodiment: Polymer (PAA))
The dianhydride used to react with the diamine to obtain a polymer is reacted regardless of whether the siloxane dianhydride (I-1) or the siloxane dianhydride (I-2) is used. The resulting polymer that is not fully cyclized (eg, polyamic acid) can have excellent solubility.

  Taking siloxane dianhydride (I-1) as an example, first, 0.1 mol of siloxane dianhydride (I-1) is dissolved in 150 ml of NMP, and then 0.1 mol of TMDA is added for polymerization. While conducting the reaction, the solid content was adjusted to 15 wt% with NMP, and after reacting for 8 hours, a polyamic acid solution (PAA-1) having a solid content of 15 wt% could be obtained.

  0.05 mol of siloxane dianhydride (I-1) and 0.05 mol of Rikacid BT-100 were dissolved in 150 ml of NMP, and then 0.1 mol of TMDA was added to conduct polymerization reaction. After adjusting the solid content to 15 wt% and reacting for 8 hours, a polyamic acid solution (PAA-2) having a solid content of 15 wt% could be obtained.

  For easy comparison, 0.1 mol of TMDA is dissolved in 150 ml of NMP, and then 0.1 mol of Rikacid BT-100 is added to conduct a polymerization reaction, so that the solid content of NMP is 15 wt%. After adjusting for 8 hours and reacting for 8 hours, a polyamic acid solution (C-PAA) having a solid content of 15 wt% can be obtained, whereby the polyamic acid solution (PAA-1) and the polyamic acid solution (PAA-) are obtained. Comparison with 2).

  Table 4 shows the solubility of the same solid content of polyamic acid solution (PAA-1), polyamic acid solution (PAA-2) and polyamic acid solution (C-PAA) in different solvents. As a method for testing the solubility, in a room temperature environment (about 25 ° C.), 2 g of a polyamic acid solution was placed in 20 g of a solvent and stirred for 30 minutes. The dissolution state was observed. The dissolution state is clear (dissolvable) as “+”, the suspension state (dissolvable) as “±”, and the precipitation state (dissolvable) as “−”. Indicated.

  From Table 4, in the diacid anhydride that undergoes a polymerization reaction with diamine, the greater the content of siloxane dianhydride (I-1), the better the solubility of the polyamic acid obtained by the reaction in various solvents. The liquid crystal aligning agent and the liquid crystal aligning film were found to be advantageous.

(Fourth embodiment: polymer (PI))
The dianhydride used to react with the diamine to obtain a polymer is reacted regardless of whether the siloxane dianhydride (I-1) or the siloxane dianhydride (I-2) is used. The resulting fully cyclized polymer (eg, polyimide) can exhibit excellent adhesion and mechanical properties after being baked.

  Taking siloxane dianhydride (I-1) as an example, first, 0.1 mol of siloxane dianhydride (I-1) is dissolved in 150 ml of NMP, and then 0.1 mol of TMDA is added for polymerization. While performing the reaction, adjust the solid content with NMP to 15 wt%, react for 8 hours, then dehydrate and cyclize with toluene to obtain a polyimide solution (PI-1) with a solid content of 15 wt%. I was able to.

  For easy comparison, 0.1 mol of hexamethyltrisiloxane dianhydride is dissolved in 150 ml of NMP, and then 0.1 mol of TMDA is added to carry out the polymerization reaction. After adjusting for 15 wt% and reacting for 8 hours, dehydration cyclization was performed using toluene to obtain a polyimide solution (C-PI) having a solid content of 15 wt%. Comparison with 1). For the preparation method of hexamethyltrisiloxane dianhydride, refer to the periodical publication high-performance polymer (High Performance Polymers, June 2008, vol. 20, no. 3, pp 281-295) published in June 2008. It's okay.

  As a comparative method, first, the polyimide solution (PI-1) and the polyimide solution (C-PI) were respectively dissolved in a solvent, and the solid content was adjusted to 6.5 wt% using the solvent. As the solvent here, NMP and BC were used and blended at a weight ratio of 1: 1. Thereafter, a polyimide solution (PI-1) and a polyimide solution (C-PI) whose solid contents are adjusted to 6.5 wt% are respectively applied to an indium tin oxide (ITO) substrate by spin coating, A polyimide thin film was formed by baking at 230 ° C. for 30 minutes using an oven.

  Next, directional brushing was performed 10 times on the polyimide thin film at a rotational speed of 1000 times / minute and a platform moving speed of 60 mm / second, and the surface after brushing was visually observed with a polarizing microscope. The polyimide thin film formed with the polyimide solution (PI-1) was observed by the microscope, and the polyimide thin film was formed with the polyimide solution (C-PI) after the brushing several times. Obviously less than.

  Further, the hardness of the polyimide thin film was tested by a pencil test method (ASTM D3363) developed by the American Society for Testing Materials. As a result, the pencil hardness of the polyimide thin film formed with the polyimide solution (PI-1) was 1B, but the pencil hardness of the polyimide thin film formed with the polyimide solution (C-PI) was 4B. From the above, for the dianhydride for reacting with diamine to obtain a polymer, according to the siloxane dianhydride according to the present invention, the fully cyclized polymer obtained by reaction is baked. After that, it has been proved that it exhibits excellent adhesion and mechanical properties, which is advantageous for the preparation of liquid crystal aligning agent and liquid crystal aligning film.

(5th embodiment: Liquid crystal aligning agent (AA), liquid crystal aligning film, and liquid crystal display element)
According to the amounts of dianhydride and diamine shown in Table 5, the dianhydride is first dissolved in 150 ml of NMP, and then the diamine is added to carry out the polymerization reaction, so that the solid content is 15 wt% with NMP. After the reaction for 8 hours, dehydration and cyclization with toluene was performed, and 8 types of solid contents were obtained with a polyimide solution of 15 wt%, that is, polyimide solution (PI-M1) to polyimide solution (PI-M8). .

  On the other hand, 0.1 mol of TMDA was taken and dissolved in 130 ml of NMP, and then 0.1 mol of CBDA was added and the polymerization reaction was carried out to adjust the solid content to 15 wt% with NMP for 8 hours. By reacting, a polyamic acid solution (M-PAA) having a solid content of 15 wt% could be obtained.

  Next, the eight kinds of polyimide solutions, that is, polyimide solution (PI-M1) to polyimide solution (PI-M8) are mixed with the polyamic acid solution (M-PAA) in a weight ratio of 1: 1, respectively, and the solvent The solid content was adjusted to 6.5 wt%. As the solvent here, NMP and BC were used and blended at a weight ratio of 1: 1. Thus, eight types of liquid crystal aligning agents, that is, liquid crystal aligning agent (AA-1) to liquid crystal aligning agent (AA-8) could be obtained. Since the siloxane dianhydride (I-1) or the siloxane dianhydride (I-2) is employed, the liquid crystal aligning agent (AA-1) to the liquid crystal aligning agent (AA-8) have excellent solubility. It was easy to apply.

  In order to make the comparison easier, according to the amounts of dianhydride and diamine shown in Table 6, the dianhydride is first dissolved in 150 ml of NMP, and then the diamine is added to perform the polymerization reaction while adding NMP. The solid content was adjusted to 15 wt%, and after reacting for 8 hours, it was dehydrated and cyclized with toluene, and three types of polyimide solutions each having a solid content of 15 wt%, namely polyimide solution (C-PI-M1) to A polyimide solution (C-PI-M3) could be obtained.

  Next, the three kinds of polyimide solutions, ie, the polyimide solution (C-PI-M1) to the polyimide solution (C-PI-M3) are mixed with the polyamic acid solution (M-PAA) at a weight ratio of 1: 1. In addition, the solid content was adjusted to 6.5 wt% with a solvent. As the solvent here, NMP and BC were used and blended at a weight ratio of 1: 1. In this way, three types of liquid crystal aligning agents for comparison, ie, liquid crystal aligning agent (C-AA-1), liquid crystal aligning agent (C-AA-2) and liquid crystal aligning agent (C-AA-3) are obtained. Thus, a comparison was made between the liquid crystal aligning agent (AA-1) to the liquid crystal aligning agent (AA-8).

  As a comparison method, first, each liquid crystal aligning agent was manufactured as a liquid crystal alignment film, and liquid crystal display elements were assembled by combining members such as liquid crystal molecules and electrodes. More specifically, the liquid crystal alignment film is formed by first applying each liquid crystal alignment agent to a glass substrate by a spin coating method to form a thin film having a thickness of 1200 · 100 · (about 0.12 μm). Baking was performed for 30 minutes at 230 ° C. using an oven (generally referred to as “post-baking”) to obtain a liquid crystal alignment film. Regarding the liquid crystal display element, first, two glass substrates on which the liquid crystal alignment film was formed were taken, a sealing agent was applied on one side, and a spacer was sprayed on the other side. After completion, the two glass substrates are combined, liquid crystal molecules (MJ012008, Merck) are injected into the gap between the two glass substrates, and then the injection hole is sealed.

  Table 7 shows the test results for the boiling cross section of the liquid crystal alignment film formed at different post-baking temperatures for each liquid crystal alignment agent, and the test results for the pretilt angle of the liquid crystal display element including the liquid crystal alignment film. In the boiling water cross-cut test, each liquid crystal alignment film was boiled and then tested using the test method (ASTM M3359) developed by the American Society for Testing Materials, and the test results were classified into ASTM grades (Table 8). Recorded). For the pretilt angle test, the liquid crystal display element into which liquid crystal molecules were injected was measured by the crystal rotation method.

  From Table 7, the liquid crystal alignment film formed by processing the liquid crystal aligning agent (C-AA-1) to the liquid crystal aligning agent (C-AA-3) at a low post-baking temperature is either vertical alignment or adhesive. It turned out that the expression of was also bad. On the other hand, the liquid crystal alignment films formed by processing the liquid crystal aligning agent (AA-1) to the liquid crystal aligning agent (AA-8) at various post-baking temperatures are all excellent in vertical alignment and adhesion. Had. In other words, the liquid crystal aligning agent (AA-1) to the liquid crystal aligning agent (AA-8) are effective in reducing the processing temperature, saving energy and reducing the burden on the environment, and the liquid crystal aligning formed thereby. The film had excellent orientation and adhesion, and was able to improve the reliability of the liquid crystal display element.

  From the above embodiments and examples of the present invention, the siloxane dianhydride according to the present invention has excellent solubility, and the polymer obtained by polymerization reaction with diamine is not completely cyclized (for example, polyamic acid). ) Inheriting the property of excellent solubility, and after completely cyclized (for example, polyimide) and baked, it can exhibit excellent adhesion and mechanical properties, both of which are liquid crystal alignment agents, liquid crystal alignment films, etc. It has been found to be advantageous for the preparation. Next, the liquid crystal aligning agent containing the polymer has good solubility and is easy to apply, and requires a low processing temperature, which is advantageous for energy saving and environmental load reduction. In addition, the liquid crystal alignment film formed of the liquid crystal aligning agent has excellent vertical alignment properties and adhesion, and can improve the product reliability of the liquid crystal display element. The liquid crystal display including the liquid crystal alignment film has excellent product reliability.

  Although the present invention has been disclosed in the embodiments as described above, this is not intended to limit the present invention, and various changes and modifications can be made by those skilled in the art without departing from the spirit and scope of the present invention. be able to. Therefore, the protection scope of the present invention is based on the contents specified in the subsequent claims.

Claims (10)

A siloxane dianhydride having a structure represented by the following formula (I):

G ₁ is formula (II) or formula (III), at least two of R _{1 to} R ₆ are phenyl groups, or at least one is —CH ₂ CH ₂ CF ₃ , and the rest are each independently monovalent An organic group, n is an integer of 0 to 30,
A siloxane dianhydride, wherein when n is 0, at least two of R ₁ , R ₂ , R ₅ and R ₆ are phenyl groups or at least one is —CH ₂ CH ₂ CF ₃ . R1~R least two ₆ one is, or at least a phenyl group but a -CH ₂ CH ₂ CF _3, in claim 1, wherein the remainder are each independently an alkyl group having 1 to 5 carbon atoms The siloxane dianhydride described. A polymer containing a polyamic acid, a polyimide or a polyamic acid-polyimide copolymer, obtained by polymerization reaction of a reactant containing a siloxane dianhydride having a structure represented by the following formula (I) and a diamine,

However, G ₁ is formula (II) or Formula (III), at least two R ₁ to R ₆ one is, or at least a phenyl group but a -CH ₂ CH ₂ CF _3, independently rest respectively 1 Valent organic group, n is an integer of 0 to 30,
A polymer, wherein when n is 0, at least two of R ₁ , R ₂ , R ₅ and R ₆ are phenyl groups or at least one is —CH ₂ CH ₂ CF ₃ . In the siloxane dianhydride having the structure represented by the formula (I), at least two of R _{1 to} R ₆ are phenyl groups or at least one is —CH ₂ CH ₂ CF ₃ , and the rest each independently has 1 carbon atom. The polymer according to claim 3, which is an alkyl group of ˜5.   The reactant further contains another dianhydride, and the content of the siloxane dianhydride is 10 mol% to 99 mol% of the total amount of the siloxane dianhydride and the other dianhydride. The polymer according to claim 3, wherein Liquid crystal alignment comprising a polymer containing a polyamic acid, a polyimide or a polyamic acid-polyimide copolymer, obtained by polymerization reaction of a diamine dianhydride having a structure represented by the following formula (I) and a diamine. An agent,

G ₁ is formula (II) or formula (III), at least two of R _{1 to} R ₆ are phenyl groups, or at least one is —CH ₂ CH ₂ CF ₃ , and the rest are each independently monovalent An organic group, n is an integer of 0 to 30,
A liquid crystal aligning agent, wherein when n is 0, at least two of R ₁ , R ₂ , R ₅ and R ₆ are phenyl groups or at least one is —CH ₂ CH ₂ CF ₃ . In the siloxane dianhydride having the structure represented by the formula (I), at least two of R _{1 to} R ₆ are phenyl groups or at least one is —CH ₂ CH ₂ CF ₃ , and the rest each independently has 1 carbon atom. The liquid crystal aligning agent according to claim 6, which is an alkyl group of ˜5.   The reactant further contains another dianhydride, and the content of the siloxane dianhydride is 10 mol% to 99 mol% of the total amount of the siloxane dianhydride and the other dianhydride. The liquid crystal aligning agent according to claim 6, wherein   A liquid crystal alignment film formed of the liquid crystal alignment agent according to claim 6.   A liquid crystal display element comprising the liquid crystal alignment film according to claim 9.

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