JPH0672964A - Liquid crystalline monomer and liquid crystalline polymer using the same - Google Patents

Abstract

PURPOSE:To provide the novel compound excellent in its orientation control, film formability, durability, thermal stability, and compatibility and useful for electro-optical liquid crystal elements, etc. CONSTITUTION:A compound of formula I [(m) is 2-14; R is group of formula II ((p) is 0-2; Rf is CF3, C2F5; R<1> is 3-18C alkyl; * is optically active carbon; A, B are 1,4-phenylene, 4,4'biphenylene, 2,6-naphthylene; X is-O-,-COO-, single bond) or group of formula III]. For example, 4-(1,1,1-trifluoro-2decyloxycarbonyl) phenyl-4'-(7-octenyloxy)biphenyl-4carboxylate. The compound of formula I is obtained e.g. by reacting a compound of formula IV with a compound of formula V. The compound of formula I and a polysiloxane of formula VI are subjected to hydrosilylation reaction to provide a liquid-crystalline high molecular compound.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel monomer and a liquid crystalline polymer modified with it.
A thin film having molecular orientational order can be formed by an appropriate orientation treatment. The compound of the present invention can be reversibly changed by an external field such as an electric field like the low molecular weight liquid crystal, and can be applied to a display element, a recording and holding element, various electro-optical devices, and a non-linear optical material. INDUSTRIAL APPLICABILITY The compound of the present invention has excellent film-forming processability and can facilitate the realization of a large-area, bent-screen type film display.

[0002]

2. Description of the Related Art A conventional liquid crystal display element is an electro-optical device mainly using a low molecular weight liquid crystal and has a TN type and a twisted TN.
Type and ferroelectric liquid crystal type driving methods have been proposed and partially put into practical use. However, the liquid crystal displays of the TN type and STN type drive systems have a slow response speed of several tens of milliseconds, a very narrow viewing angle, and it is difficult to support high-speed drive type software. In addition, it was thought that the driving method using the ferroelectric liquid crystal could realize a large size and high quality display due to 1) high speed response and 2) memory property.
At present, there are many difficult problems for practical application. The side-chain type polymer liquid crystal has a structure in which mesogenic groups are bonded to the polymer skeletal chain through a flexible spacer, has self-supporting properties, can be formed into a film, and can be used for curved surface processing of display screens. And it is easy to increase the screen size. For liquid crystal displays using polymer liquid crystals, 1) nematic type, 2) cholesteric type, 3) ferroelectric type, etc. have been proposed, but there are various problems for practical use. That is, compared with a low molecular weight liquid crystal, the response speed is extremely slow, being several hundred milliseconds, because of its high viscosity, which is not practical. Insufficient alignment uniformity. Practical electro-optical characteristics cannot be obtained. In order to solve these problems, (1) investigation of various main chain structures and liquid crystal groups, (2) composite system of polymer liquid crystal and low molecular weight liquid crystal, and (3) dispersion of low molecular weight liquid crystal into polymer liquid crystal Matrix polymer liquid crystals and the like have been proposed. However, in these conventional techniques, it is difficult to obtain a homogeneous and stable liquid crystal phase without causing phase separation, and it is not easy to realize low viscosity and high-speed response in a sufficiently wide temperature range including room temperature. On the other hand, Tokyo Institute of Technology Kakimoto, Cray, Mr. Imai and others have a liquid crystal polymer having a polysiloxane structure in the main chain structure and an ester type mesogen component having an asymmetric carbon structure at the end of the side chain part Announced the synthesis (The 61st Annual Meeting of the Chemical Society of Japan, March 29, 1991),
Moreover, an invention including the contents thereof is applied for as Japanese Patent Application No. 3-276853.

[0003]

The object of the present invention is to further develop a polysiloxane type liquid crystalline high molecular polymer so that a liquid crystal phase is easily developed, and orientation controllability, film formability, durability,
It is an object of the present invention to provide an improved liquid crystalline monomer which is excellent in thermal stability and compatibility and can be used in electro-optical liquid crystal devices, recording holding devices and the like, and a liquid crystalline polymer compound using the same.

[0004]

The first feature of the present invention is that it is most characteristic of the invention of the above-mentioned Japanese Patent Application No. 3-276853 that an asymmetric carbon atom has a methyl group. The present invention is dependent on the point that CF ₃ or C ₂ F ₅ is hung. That is, the first aspect of the present invention is the following general formula:

[Chemical 6] [In the formula, m is an integer of 2 to 14, and R is

[Chemical 7] (In the formula, p is 0, 1 or 2, Rf is CF ₃ or C ₂
F ₅ and R ¹ are alkyl groups having 3 to 18 carbon atoms, * is optically active carbon, and (A) and (B) are

[Chemical 8] A group independently selected from the group consisting of
It may be substituted with one or more halogen atoms. X is -O-, -COO- or a single bond. )and

[Chemical 9] (In the formula, p, Rf, R ¹ , (A), (B), X and * are the same as the above), which is a group selected from the group consisting of]. .

The second aspect of the present invention is the following general formula:

[Chemical 10] [Wherein, m and R are the same as those described above, and n represents a repeating unit of polysiloxane], which is a liquid crystalline polymer. The number of n is not particularly limited as long as the high molecular polymer exhibits liquid crystal, but n is usually 1 to
100, preferably 2 to 50, particularly preferably 3 to 4
It is 0. That is, the liquid crystalline polymer of the present invention,
1) Introducing an asymmetric carbon into the molecular structure of the mesogen component,
2) A ferroelectric liquid crystal phase is developed by generating a dipole moment perpendicular to the long axis of the molecule. By imparting ferroelectricity to a high-molecular liquid crystal polymer, high-speed and large-area display is possible. It was Further, the main chain structure has an important influence on the expression of a liquid crystal phase, the range of phase transition temperature, the mobility of side chains, and the like. In the present invention, a flexible polysiloxane structure is used as the main chain structure to provide a high-speed response, reduce the glass transition point (Tg), and enable room temperature response.

The details of the present invention will be described below. The liquid crystalline polymer compound having the monomer represented by the formula [1] and the repeating unit represented by the formula [2] is produced, for example, by the following synthetic route. (1) Production of mesogen component As shown in the following reaction formula, 4-benzyloxybenzoic acid chloride and optically active 1,1,1-trifluoro-2-octanol are reacted in the presence of a base in dichloromethane to give an optical compound. Active 1,1,1-trifluoro-2-octyl 4-benzyloxybenzoate is synthesized. This was debenzylated with palladium carbon under a hydrogen atmosphere to obtain optically active 1,1,1-trifluoro-2-octyl 4-hydroxybenzoate (formula [a]). On the other hand, 4-hydroxybiphenyl-4′-carboxylic acid methyl ester and ω-alkenyl bromide are reacted with anhydrous potassium carbonate to obtain 4- (ω-alkenyloxy) biphenyl-4′-carboxylic acid methyl ester. This product is ester-hydrolyzed in the presence of alkali to give 4-
(Ω-Alkenyloxy) biphenyl-4′-carboxylic acid [b] was obtained, which was then converted to the acid chloride [b ′]. Optically active 1,1,1-trifluoro-of the formula [a]
2-Octyl 4-hydroxybenzoate was reacted with the acid chloride of the formula [b '] to produce the mesogen component compound [c].

[0007]

[Chemical 11]

[0008]

[Chemical 12]

The carbon number m of the terminal alkenyl side chain is an important structural factor involved in the liquid crystal properties to be formed, and in the present invention, m is in the range of 2 to 20, preferably 2 to 14.

(2) Production of main chain polymer N mol of dichloromethylsilane and M mol of trimethylsilyl chloride were added to tetrahydrofuran (T) in the presence of concentrated hydrochloric acid.
Low temperature polymerization is carried out in HF) to obtain the target compound [d].

[Chemical 13]

(3) Production of Liquid Crystalline Polymer Polymer The liquid crystalline polymer compound can be produced, for example, by subjecting a mesogen component formula [c] and a main chain polysiloxane formula [d] to a hydrosilylation reaction. it can. That is, the compound [c] and the polysiloxane [d] can be dissolved in a reaction solvent and heated to an appropriate temperature, and then a platinum catalyst can be added to bond them. The reaction solvent that can be used in the present invention includes ethers such as dioxane,
Tetrahydrofuran, diethyl ether or chlorinated solvents such as dichloromethane, trichloromethane,
1,2-dichloroethane and hydrocarbons such as n-hexane, heptane, octane, petroleum ether, benzene, toluene, acetone, methyl ethyl ketone and the like can be mentioned. Preferred are dichloromethane, trichloromethane, benzene and toluene. As the platinum catalyst, PtCl ₄ , H ₂ PtCl ₆ 6H ₂ O, platinum-alcohol complex, platinum-olefin complex and the like are used, and dicyclopentadienyl Pt (II) chloride is preferable. (Below margin)

[0012]

[Chemical 14]

Further, as a method for producing a liquid crystalline polymer compound having a monomer represented by the above formula [1] and a repeating unit represented by the above formula [2], 4-benzyloxybenzoic acid chloride represented by the above reaction formula is used. In place of 2-benzyloxynaphthalene-6-carboxylic acid chloride (g),
A mesogen component represented by the following formula can be produced by a completely similar synthetic method. (Below margin)

[0014]

[Chemical 15]

[0015]

[Chemical 16]

It can also be produced by the following polymerization method. First step: Compound [c] and dichloromethylsilane are dissolved in a reaction solvent and heated to an appropriate temperature, and then a platinum catalyst is added to carry out hydrosilylation to obtain silylated compound [k] of compound [c]. ]] Is obtained. Examples of the reaction solvent which can be used in this reaction include ethers such as dioxane, tetrahydrofuran, diethyl ether, and chlorinated solvents such as dichloromethane, trichloromethane, 1,
2-dichloroethane and also hydrocarbons such as n-hexane, heptane, octane, petroleum ether, benzene,
Toluene, acetone, methyl ethyl ketone, etc. may be mentioned. Preferably, dichloromethane, trichloromethane,
Benzene and toluene. As a platinum catalyst, P
Although tCl ₄ , H ₂ PtCl ₆ 6H ₂ O, platinum-alcohol complex, platinum-olefin complex and the like are used, dicyclopentadienyl Pt (II) chloride can be said to be preferable. Second stage: Polymerization reaction of silyl compound [k] N mol of silyl compound [k] and trimethylsilyl chloride M
The desired compound [f] is obtained by polymerizing 1 mol and mol in THF in the presence of water. (Below margin)

[0017]

[Chemical 17]

[0018]

【Example】

Example 1 Synthesis of 4- (1,1,1-trifluoro-2-decyloxycarbonyl) phenyl 4 '-(7-octenyloxy) biphenyl-4-carboxylate

[Chemical 18]

[Chemical 19] 1.23 g of 4-benzyloxybenzoic acid chloride was dissolved in 10 ml of methylene chloride, and then the optically active 1,2
1,1-trifluoro-2-decanol [α] D ²⁰ = + 23.1 [C = 0.9453 (wt / v
sol%), in CHCl ₃ ] 0.96 g, dimethylaminopyridine 0.55 g and triethylamine 0.48 g dissolved in 20 ml of methylene chloride were added little by little under ice cooling. The reaction mixture was returned to room temperature, reacted overnight, poured into ice water, extracted with methylene chloride,
The methylene chloride phase was washed successively with diluted hydrochloric acid, water, a 1N aqueous sodium carbonate solution and water, dried over anhydrous magnesium sulfate and the solvent was distilled off to obtain a crude product. Toluene-
Treatment with silica gel column chromatography gave 1.71 g of 4-benzyloxybenzoic acid-1,1,1-trifluoro-2-decyl ester. This compound was dissolved in 15 ml of ethanol, and 10% loaded Pd-carbon 0.3
6 g was added and hydrogenation reaction was carried out under hydrogen atmosphere to obtain the target compound 4-hydroxybenzoic acid 1,1,1-trifluoro-2.
-1.34 g of decyl ester are obtained.

[0019]

[Chemical 20] 2.3 g of 4-hydroxybiphenyl 4'-carboxylic acid methyl ester, 1.9 g of 7-octenyl bromide and 2.1 g of anhydrous potassium carbonate were added to 50 ml of an acetone solvent, and the mixture was gently refluxed for about 8 hours. This is ice water 5
It was poured into 00 ml, extracted with methylene chloride, the organic layer was recovered and desolvated, and further subjected to silica gel chromatography to obtain 3.1 g of an organic substance. KOH this
1.6 g of the solution was added to 30 ml of dissolved methanol, and the mixture was gently refluxed all day and night. Then, the mixture was poured into 300 ml of ice water, the white powder deposited was filtered off, washed thoroughly with water, neutralized with 1N HCl, collected and dried to give the target compound 4- (7-octenyloxy) biphenyl. 4 '
-2.6 g of carboxylic acid are obtained.

[0020]

[Chemical 21] 1.3 g of 4- (7-octenyloxy) biphenyl 4'-carboxylic acid was added under reflux with excess thionyl chloride to give 6
After heating for an hour, unreacted thionyl chloride was distilled off to remove 4-
(7-octenyloxy) biphenyl 4'-carboxylic acid chloride was obtained. This acid chloride was converted to methylene chloride 12.0
1.34 g of 1,1,1-trifluoro-2-decyl ester of 4-hydroxybenzoic acid synthesized above, 0.41 g of triethylamine and 0.3 g of dimethylaminopyridine were dissolved in 30 ml of methylene chloride. The resulting mixture was gradually added under ice-cooling and reacted at room temperature overnight. Then, the reaction solution was poured into ice water and extracted with methylene chloride, and the methylene chloride phase was washed with diluted hydrochloric acid, water, an aqueous solution of sodium carbonate, and water in this order, dried over anhydrous sodium sulfate, and then the solvent was distilled off. , A crude product was obtained. This was purified by a toluene-silica gel column chromatography method to give the optically active target compound 4- (1,1,1-
1.6 g of trifluoro-2-decyloxycarbonyl) phenyl 4- (7-octenyloxy) biphenyl-4'-carboxylate were obtained. Of the obtained target compound
The results of ¹ H-NMR analysis are shown below. ¹ H-NMR (CDCl ₃ ) δppm 6.8-7.3 (12H, m, Ar-H) 5.3-6.0 (2H, m, CHCF ₃ / CH = CH ₂ ) 4.8-5 .1 (2H, m, CH = CH 2) 4.0 (2H, t, O-CH 2) 1.6-2.2 (6H, m, CH 2) 1.1-1.6 (18H, m, CH ₂ ) 0.8 (3H, t, CH ₃ )

Example 2 (1) Synthesis of 4- (1,1,1-trifluoro-2-decyloxycarbonyl) phenyl 4- (8-dichloromethylsilyl) octyloxybiphenyl-4'-carboxylate

[Chemical formula 22] 1 g of the mesogen component compound (3) of Example 1 and 160 μl of dichloromethylsilane were dissolved in dry toluene,
0.12 M THF solution of chloroplatinic acid under nitrogen atmosphere 4
After adding a drop, the mixture was stirred at 50 ° C. for 16 hours. After confirming the disappearance of the Si—H characteristic absorption peak at 2170 cm ⁻¹ by infrared absorption spectrum analysis, the reaction solution was cooled to room temperature. After the solid matter was filtered off under a nitrogen atmosphere, the solvent was distilled off to obtain a milky yellow oily target compound. This one is
It was used as a raw material for the next polymerization reaction without further purification.

(2) Synthesis of liquid crystalline polymer

[Chemical formula 23] The total amount of the compound obtained in (1) above was 1 under nitrogen atmosphere.
Dissolve in 0 ml of THF and stir at 0 ° C. for 0.6 m
1 l of distilled water was gradually added dropwise. After stirring for 15 minutes, 0.4 ml of pyridine was added, and while gently refluxing, 22
Polymerized for hours. Then, trimethylchlorosilane 20
After adding μl, the mixture was gently refluxed for 5 hours. After completion of the reaction, excess methanol was added at room temperature to precipitate a polymer. The precipitate was dissolved again in THF, and this precipitation operation was repeated several times to purify the polymer. The physical properties of the obtained liquid crystalline polymer and the phase transition temperature by observation with a polarizing microscope equipped with a hot stage are as follows. Number average molecular weight Mn = 9,527 Mn / Mw = 1.17 (Note Mw: weight average molecular weight)

[Table 1]

Example 3 An electro-optical cell having a cell thickness of 3 μm and having a rubbing-treated polyimide alignment film on an ITO electrode substrate was filled with the liquid crystalline polymer obtained in Example 2 in an isotropic phase to give a liquid crystallinity. A polymer thin film cell was prepared. This liquid crystal cell was placed in a polarizing microscope with a photomultiplier, which was orthogonal to each other with two polarizing plates, so as to have a dark field at a voltage of 0V. This liquid crystal cell is gradually cooled with a temperature gradient of 0.1 to 1.0 ° C./min, and is ± 40 V in the temperature range of 40 to 70 ° C.
Pulse voltage was applied. The measurement results of the response speed obtained from the change in transmittance are shown below.

[Table 2] (The following margin)

Example 4 Synthesis of Liquid Crystalline Polymer

[Chemical formula 24] (1) Synthesis of 4- (1,1,1-trifluoro-2-decyloxycarbonyl) phenyl 4 '-(5-hexenyloxy) biphenyl-4-carboxylate

[Chemical 25] A mesogen component compound was obtained in exactly the same manner by using 1.7 g of 5-hexenyl bromide instead of 1.9 g of 7-octenyl bromide in (2) of Example 1.

(2) 4- (1,1,1-trifluoro-
2-decyloxycarbonyl) phenyl 4- (6-dichloromethylsilyl) hexyloxybiphenyl-4 '
-Synthesis of carboxylates

[Chemical formula 26] The above dichloromethylsilyl derivative was synthesized in the same manner as in Example 2 (1), except that 1 g of the mesogen component compound of (1) above was used instead of 1 g of the mesogen component compound of Example 1 (1).

(3) Synthesis of liquid crystalline polymer

[Chemical 27] Instead of the dichloromethylsilyl derivative of (2) of Example 2, 4- (1,1,1-trifluoro-2-decyloxycarbonyl) phenyl 4- (6 obtained in (2) above was used.
-Dichloromethylsilyl) hexyloxybiphenyl-
A liquid crystalline polymer was obtained by the same method as in (2) of Example 2 using the entire amount of 4'-carboxylate.
The physical properties of the obtained liquid crystalline polymer and the phase transition temperature by observation with a polarizing microscope equipped with a hot stage are as follows. Number average molecular weight Mn = 11,000

[Table 3]

Example 5 Synthesis of liquid crystalline polymer

[Chemical 28] Of the optically active 1,1,1-trifluoro-2-decanol of Example 1 (1) and 4-hydroxybiphenyl 4'-carboxylic acid methyl ester of Example 1 (2) and 7-octenyl bromide. Instead, each of the optically active 1,1,1-trifluoro-2-octanol 0.9
6 g, 4-hydroxy-3'-fluorobiphenyl
The liquid crystalline polymer of the above formula was produced in the same manner as in Example 1 and Example 2 using 2.3 g of 4'-carboxylic acid methyl ester and 1.2 g of 3-butenyl bromide. The physical properties of the obtained liquid crystalline polymer and the phase transition temperature by observation with a polarizing microscope equipped with a hot stage are as follows. Number average molecular weight Mn = 1,800

[Table 4]

Example 6 Synthesis of liquid crystalline polymer

[Chemical 29] Instead of the optically active 1,1,1-trifluoro-2-decanol of (1) of Example 1 and the 7-octenyl bromide of (2) of Example 1, optically active 1,1,1- Using 0.96 g of trifluoro-2-octanol and 1.9 g of 5-hexenyl bromide, a liquid crystalline polymer was produced in the same manner as in Example 1 and Example 2.
The physical properties of the obtained liquid crystalline polymer and the phase transition temperature by observation with a polarizing microscope equipped with a hot stage are as follows. Number average molecular weight Mn = 4,300

[Table 5]

Example 7 Examples 4 and 5 were applied to an electro-optical cell having a cell thickness of 3 μm and having a rubbing-treated polyimide alignment film on an ITO electrode substrate.
The liquid crystalline polymer obtained in 6 was filled in the isotropic phase to prepare a thin film cell of the liquid crystalline polymer. This liquid crystal cell was placed in a polarizing microscope with a photomultiplier in which two polarizing plates are orthogonal to each other so as to have a dark field at a voltage of 0V. This liquid crystal cell is gradually cooled with a temperature gradient of 0.1 to 1.0 ° C./min, and is ± within a temperature range of 40 to 90 ° C.
A pulse voltage of 40 V was applied. The measurement results of the response speed obtained from the change in transmittance are shown below.

[0030]

[Table 6]

[Table 7]

[Table 8]

[0031]

[Effect] The novel liquid crystalline polymer of the present invention is excellent in film forming processability and can facilitate the realization of a large area, bent screen type film display.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C09K 19/38 7457-4H

Claims (2)

[Claims] 1. The following general formula: [In the formula, m is an integer of 2 to 14, and R is (In the formula, p is 0, 1 or 2, Rf is CF ₃ or C ₂
F ₅ and R ¹ are alkyl groups having 3 to 18 carbon atoms, * is an optically active carbon, and (A) and (B) are It is a group independently selected from the group consisting of, and may be substituted with one or more halogen atoms. X is -O-,-
COO- or a single bond. ) And (In the formula, p, Rf, R ¹ , (A), (B), X and * are the same as the above), which is a group selected from the group consisting of]. 2. The following general formula: [In the Formula, m and R are the same as the above, and n shows the repeating unit of polysiloxane. ] A liquid crystalline polymer represented by the following formula.