JPH0816223B2 - Ferroelectric liquid crystal composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of optoelectronics, in particular, display devices such as calculators and watches, electro-optical shutters, electro-optical diaphragms, optical modulators, optical communication optical path changeover switches, memories, liquid crystal printer heads, variable focal lengths. The present invention relates to a ferroelectric liquid crystal composition used for various electro-optical devices such as lenses.

[0002]

2. Description of the Related Art Conventionally, a ferroelectric polymer is superior in film forming property and alignment property to a low molecular weight ferroelectric liquid crystal, but has a problem that it is inferior in high speed response. In order to solve this problem, it is known to add a non-chiral liquid crystal compound or a non-liquid crystal chiral compound to a ferroelectric polymer (JP-A-2-212587). However, the polyacrylate main chain, the polymethacrylate main chain, the polychloroacrylate main chain, the polyoxirane main chain, the polysiloxane main chain, which are specifically mentioned here,
Most of the ferroelectric liquid crystal polymers having a polyoxyester main chain have a high glass transition temperature and do not exhibit the properties as liquid crystals at around room temperature. Further, the temperature range in which the liquid crystal phase is exhibited is narrow, and therefore, the liquid crystal composition to which the low molecular weight compound is added has a drawback that phase separation is likely to occur.

[0003]

DISCLOSURE OF THE INVENTION The present invention exhibits ferroelectricity in a wide temperature range including room temperature, is excellent in film-forming property, is hard to cause phase separation, and has good orientation, that is, orientation is disturbed. It is an object of the present invention to provide a hard ferroelectric liquid crystal composition.

[0004]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that a non-liquid crystal chiral compound is blended with a ferroelectric polymer composed of a specific liquid crystal copolymer. As a result, they have found that the above-mentioned object can be achieved, and have completed the present invention based on this finding.

That is, the present invention provides a repeating unit represented by the following general formula.

[Chemical 4] [In the Formula, r and p are integers of 2-5, q is an integer of 0-3,
m is an integer of 1 to 20 and R ¹ is

Embedded image Is. However, R ² is -COOR ³ , -OR ³ or-.
OCOR ³ and R ³ is

[Chemical 6] R ⁴ and R ⁵ are —CH ₃ or a halogen atom, and a, d
Is an integer of 0 to 10 and b is 0 or 1 (d is not 0 when R ⁵ is —CH ₃ ). And a liquid crystal copolymer [A] having a molar ratio of [I] and [II] of about 1: 1 and a non-liquid crystal chiral compound [B]. is there.

The preferred number average molecular weight (Mn) of the liquid crystalline copolymer of the present invention is 1,000 to 400,000, more preferably 1,000 to 20,000. Mn is 1,
When it is less than 000, the polymer may have an adverse effect on the moldability as a film or a coating film.
If it exceeds 000, unfavorable effects such as long response time may be exhibited.

The liquid crystal copolymer in the ferroelectric liquid crystal composition of the present invention is, for example, a diene compound represented by the following general formula.

[Chemical 7] (In the formula, r, p, m and R ¹ are the same as the above.) And a silicon compound represented by the following general formula.

Embedded image (In the formula, q is the same as the above) and can be produced by carrying out the hydrosilylation reaction in the presence of a catalyst in a solvent in an approximately equimolar ratio.

As a solvent for carrying out the hydrosilylation reaction of the compound [III] and the compound [IV], an inert aromatic hydrocarbon having a boiling point of 70 ° C. or higher such as benzene, toluene and xylene, and a boiling point of 70 ° C. such as tetrahydrofuran and diisopropyl ether. The above inert ether solvents and the like are preferably used. As the catalyst, a platinum catalyst such as chloroplatinic acid or dicyclopentadienylplatinum chloride is preferably used. Also, the reaction is preferably carried out at 60 to 90 ° C. for 5 to 20 hours under an inert atmosphere.

General formula used as a raw material for producing the above copolymer

[Chemical 9] By having the repeating unit derived from the diene compound represented by, the viscosity of the copolymer is lowered and the response speed to the electric field change is increased.

The compound [III] has, for example, the general formula

[Chemical 10] (In the formula, r and p are integers of 2 to 5.) and an alcohol [V] represented by the general formula X (CH ₂ ) _m X (wherein, m is an integer of 1 to 20 and X is Br, I or OS
O is ₂ -Ph-CH _3. ) And a bifunctional compound [VI] represented by the formula (I) in the presence of an alkaline reagent in a solvent, an etherification reaction, and a product obtained by purifying the obtained reaction mixture, and a general formula HO-R ¹ (In the formula, R ¹ is the same as above.) And the hydroxy compound [VII] can be produced by carrying out an etherification reaction in a solvent in the presence of an alkaline reagent.

The reaction proceeds as follows, for example.

[Chemical 11]

After the etherification reaction of the alcohol [V] and the bifunctional compound [VI] in a solvent in the presence of an alkaline reagent to obtain (1), and the hydroxy compound [VII] in a solvent, The desired diene compound [III] is obtained by carrying out an etherification reaction in the presence of an alkaline reagent.

Specific examples of the alcohol [V] include 1,4-pentadiene-3-ol, 1,5-hexadiene-3-ol, 1,6-heptadien-3-ol and 1,7-octadiene-3. -Ol, 1,6-heptadien-4-ol, 1,7-octadiene-4-ol and the like.

Specific examples of the bifunctional compound [VI] include dibromomethane, diiodomethane, methanediol ditosylate, dibromoethane, diiodoethane,
Ethanediol ditosylate, dibromopropane, diiodopropane, propanediol ditosylate, dibromobutane, diiodobutane, 1,4-butanediol ditosylate, dibromopentane, diiodopentane, pentanediol ditosylate, dibromohexane, diiodohexane, hexanediol Ditosylate, dibromoheptane, diiodoheptane, heptanediol ditosylate, dibromooctane, diiodooctane, octanediol ditosylate, dibromononane, diiodononane, nonanediol ditosylate,
Dibromodecane, diiododecane, decanediol ditosylate, dibromoundecane, diiodoundecane, undecanediol ditosylate, dibromododecane, diiododecane, dodecanediol ditosylate, dibromotridecane, diiodotridecane, tridecanediol ditosylate, dibromotetradecane, diiodo Tetradecane, tetradecanediol ditosylate, dibromopentadecane, diiodopentadecane, pentadecanediol ditosylate, dibromohexadecane, diiodohexadecane, hexadecanediol ditosylate, dibromoheptadecane, heptadecanediol ditosylate,
Dibromooctadecane, diiodooctadecane, octadecanediol ditosylate, dibromononadecane,
Examples include diiodononadecane, nonadecanediol ditosylate, dibromoeicosane, diiodoeicosane and eicosanediol ditosylate.

As R ¹ --OH [VII],

[Chemical 12] The compound represented by is preferably used. Where R ² is −
COOR ³ , —OR ³ or —OCOR ³ , and R ³ is the above-mentioned optically active group.

The optically active group in R ² is an optically active alcohol R ³ -0H, using an optically active carboxylic acid R ³ COOH are introduced by using the following reaction in R ^{2. -COOH + R 3 OH → -COOR 3} -OH + R 3 OSO 2 -Ph-CH 3 → -OR 3 -OH + R 3 COOH → -OCOR 3

Optically active alcohol R ³ --OH used here
As, (+)-2-methylbutanol, (-)-
2-methylbutanol, (+)-2-chlorobutanol, (−)-2-chlorobutanol, (+)-2-methylpentanol, (−)-2-methylpentanol,
(+)-3-methylpentanol, (-)-3-methylpentanol, (+)-4-methylhexanol,
(−)-4-methylhexanol, (+)-2-chloropropanol, (−)-2-chloropropanol,
(+)-6-methyloctanol, (-)-6-methyloctanol, (+)-2-cyanobutanol, (-)
-2-cyanobutanol, (+)-2-butanol,
(−)-2-butanol, (+)-2-pentanol,
(−)-2-Pentanol, (+)-2-Octanol, (−)-2-Octanol, (+)-1,1,1-
Trifluoro-2-octanol, (-)-1,1,1
-Trifluoro-2-octanol, (+)-2-fluorooctanol, (-)-2-fluorooctanol, (+)-2-fluorohexanol, (-)-2-
Fluorohexanol, (+)-2-fluorononanol, (−)-2-fluorononanol, (+)-2-chloro-3-methylpentanol, (−)-2-chloro-
3-methylpentanol and the like can be mentioned.

Here, the optically active carboxylic acid R ³ --COOH
Specifically, (+)-2-methylbutanoic acid,
(−)-2-Methylbutanoic acid, (+)-2-Chlorobutanoic acid, (−)-2-Chlorobutanoic acid, (+)-2-Methylpentanoic acid, (−)-2-Methylpentanoic acid, (+)
-3-methylpentanoic acid, (-)-3-methylpentanoic acid, (+)-4-methylhexanoic acid, (-)-4-methylhexanoic acid, (+)-2-chloropropanoic acid, (-)
-2-chloropropanoic acid, (+)-6-methyloctanoic acid, (-)-6-methyloctanoic acid, (+)-2-cyanobutanoic acid, (-)-2-cyanobutanoic acid, (+)-2
-Fluorooctanoic acid, (-)-2-fluorooctanoic acid, (+)-2-chloro-3-methylpentanoic acid,
(−)-2-chloro-3-methylpentanoic acid and the like can be mentioned.

An aprotic polar solvent such as tetrahydrofuran or N, N-dimethylformamide is preferably used as a solvent for the etherification reaction, and a metal hydride such as sodium hydride is used as an etherification reaction reagent. A metal hydroxide such as potassium hydroxide or sodium hydroxide or a basic compound capable of ionizing -OH is preferably used.

In the etherification reaction, an alkaline reagent is introduced into a mixed solution of alcohol [V] and a solvent, and alkoxide is formed at room temperature. (However, in the case of a compound and a reagent having low reactivity, it is heated.) Then, the dibromo compound [VI] is introduced, and the mixture is heated and stirred at 60 to 100 ° C.

Further, as the solvent for the etherification reaction,
For example, a ketone-based solvent such as acetone or methyl ethyl ketone, an ether-based inert solvent such as tetrahydrofuran or ether, or a lower alcohol such as methanol or ethanol is preferably used, and examples of the etherification reaction reagent include carbonate such as potassium carbonate and sodium carbonate. Salts or metal hydroxides such as potassium hydroxide and sodium hydroxide are preferably used. The etherification reaction is carried out by using a hydroxy compound [VII], a dibromo compound [VI], an alkaline reagent,
It is carried out by introducing the solvents in random order and heating and stirring at 60 to 100 ° C.

Compound [III] can be produced by the method of the general formula in addition to the method described above.

[Chemical 13] (In the formula, r and p are integers of 2 to 5.) and an alcohol [V] represented by the general formula X (CH ₂ ) _m X (wherein, m is an integer of 1 to 20 and X is Br, I or OS
O is ₂ -Ph-CH _3. ) A bifunctional compound [VI] represented by the formula (1) is subjected to an etherification reaction in a solvent in the presence of an alkaline reagent, and the resulting reaction mixture is purified to obtain a product and a general formula

Embedded image (In the formula, e is 1 or 2.) [V
III] and a solvent in the presence of an alkaline reagent in the presence of an alkaline reagent, the resulting reaction mixture is filtered to hydrolyze the product obtained in alkali, water or alcohol, and the obtained reaction solution is placed in water. It is charged, hydrochloric acid is added to make the pH acidic, and then the mixture is extracted with ether, and the solid obtained by removing the ether is reacted with an acid halogenating agent, and the obtained acid chloride and the general formula HO-A-R ² (wherein A is

[Chemical 15] Is. ) And the hydroxy compound [IX] represented by the formula (1) can be produced by carrying out an esterification reaction in a solvent.

The reaction proceeds as follows, for example.

Embedded image Hydroxy compound used in esterification reaction [I
X]

[Chemical 17] The compound represented by is used, and the optically active group of R ² is introduced in the same manner as described above.

The production of compound (1) by the etherification reaction is the same as described above. Then with compound (1)

Embedded image The compound [VIII] represented by is subjected to an etherification reaction in a solvent in the presence of an alkaline reagent to obtain a compound (3).

Then, the compound (4) is hydrolyzed by heating in an alkali, water or alcohol as required, and then a halogenation reaction is carried out using an acid halogenating agent to obtain an acidified substance. hydroxy compounds of the formula HO-a-R ² and [IX], triethylamine, T
An esterification reaction is carried out with an HF solvent or the like to obtain the target diene compound (5), that is, the diene compound [III].

Specific examples of the compound [VIII] include methyl 4-hydroxybenzoate and methyl 4'-hydroxybiphenyl-4-carboxylic acid ester.
The solvent, the reagent and the reaction condition in the etherification reaction are the same as the solvent, the reagent and the reaction condition in the etherification reaction.

In the hydrolysis, metal hydroxides such as potassium hydroxide and sodium hydroxide are preferably used as the alkali, and methanol is used as the alcohol.
Water-soluble lower alcohols such as ethanol are preferably used. The hydrolysis reaction may be carried out by heating only with an ester, an alkali catalyst, and water, but if alcohol is further added, the solubility of the ester compound as a raw material is improved and the reaction proceeds easily.

For the halogenation reaction of, known acid halogenating agents such as thionyl chloride, phosphorus oxychloride, phosphorus pentachloride and the like are used. As the solvent for the esterification reaction, for example, an ether inert solvent such as tetrahydrofuran and a hydrocarbon inert solvent such as toluene and hexane are preferably used.

The esterification reaction is carried out by introducing an acid chloride or an acid chloride dissolved in a solvent into a solution of a hydrogen halide acceptor such as pyridine or a tertiary amine such as triethylamine, and stirring the mixture. Further, when the reactivity is low, it may be heated to 20 to 80 ° C.

Next, as the silicon compound [IV] having two Si—H bonds, which is a raw material for producing the copolymer of the present invention, 1,1,3,3-tetramethyldisiloxane,
1,1,3,3,5,5-hexamethyltrisiloxane, 1,1,3,3,5,5,7,7-octamethyltetrasiloxane, 1,1,3,3,5,5,5 7, 7,
Examples include 9,9-decamethylpentasiloxane.

As described above, the liquid crystalline copolymer [A] of the present invention is obtained. The following can be mentioned as specific examples of the liquid crystalline copolymer.

[Chemical 19]

Embedded image

[Chemical 21]

Next, as the non-liquid crystal chiral compound [B] used in the present invention, the following compounds are preferably used.

[Chemical formula 22]

Further, a compound represented by the following general formula can also be used.

[Chemical formula 23](R in the formula ⁶ Is a halogen atom, hydroxyl group, pheno
Xy, Toluenesulfonyloxy, Acetyloxy
Group, trifluoroacetyloxy group, etc., R⁷Is
C1-C16 alkyl, alkoxy, alkano
Iloxy group, C^*Is an asymmetric carbon atom, and a and b are each
0 or 1. ) Specific examples include the following compounds
Is mentioned.

[Chemical formula 24] Non-liquid crystal chiral compound [B] used in the present invention
These may be used alone or in combination of two or more.

The proportion of the non-liquid crystal chiral compound in the whole composition is preferably 5 to 95% by weight. 5% by weight
If it is less than 100% by weight, the film-forming property is remarkably deteriorated. When the proportion of the non-liquid crystal chiral compound increases, the SmC ^* phase temperature range generally shifts to the low temperature side or the temperature range of the SmC ^* phase range narrows. Also, the tilt angle is reduced. Therefore, when the liquid crystal composition of the present invention is used as a display material, the proportion of the non-liquid crystal chiral compound is preferably 20 to 40% by weight in order to obtain a practical temperature range and good contrast.

[0035]

The present invention will be described below with reference to examples.
The present invention is not limited to this. The electric field response speed was measured as follows. 1.5 μm in thickness by shearing method by sandwiching the ferroelectric composition between two ITO substrates
An oriented cell of was prepared. Furthermore, under crossed Nicols ± 10
An electric field of MV / m was applied, and the time at which the amount of change in light transmittance reached 10 to 90% was measured. In the formula showing the phase transition behavior, each symbol has the following meaning. Cry:
Crystal phase, g: glass state, SmC ^* : chiral smectic C liquid crystal phase, SmA: smectic A liquid crystal phase, Is
o: isotropic liquid, Sm1: unidentified smectic liquid crystal phase

Synthesis Example 1 Synthesis of Liquid Crystalline Copolymer A

[Chemical 25]

[Chemical formula 26] 0.1 mol of 1,5-hexadecen-3-ol and 0.17 mol of sodium hydride are stirred in 150 ml of THF at room temperature for 1 hour. Then 1,10-dibromodecane 0.
Introduce 3 mol and reflux for 12 hours. The reaction solution was filtered, concentrated, and purified by column chromatography to obtain the target ether (1). (Yield 63%)

[0037]

[Chemical 27] A solution of 60 mmol of the ether body (1) obtained above, 60 mmol of 4-hydroxybenzoic acid methyl ester and 0.2 mol of potassium carbonate in 150 ml of acetone was refluxed for 12 hours. The reaction solution was filtered, concentrated, and purified by column chromatography to obtain the target ether (2). (Yield 77%)

[0038]

[Chemical 28] 30 mmol of the ether compound (2) obtained in [2], 0.1 mol of sodium hydroxide, 50 ml of ethanol and water 2
Reflux 0 ml of solution for 30 minutes. The reaction solution was poured into 500 ml of water, the pH was adjusted to 2 with diluted HCl water, and the reaction solution was extracted with ether and dried to obtain the desired carboxylic acid derivative (3). (Yield 96%)

[0039]

[Chemical 29] 43.2 g of the carboxylic acid derivative (3) obtained in [3],
34 ml of thionyl chloride and 130 ml of toluene were sampled in a 1000-neck four-necked flask equipped with a reflux condenser and stirred to obtain a uniform solution. Next, after adding 0.2 ml of pyridine, the reaction temperature was raised to 65 ° C. and 4
The heating and stirring were continued for an hour. Then, the reaction mixture was heated under reduced pressure at 65 ° C. for 1 hour and further at 80 ° C. for 30 minutes using an aspirator to remove toluene and remaining thionyl chloride. Then, 170 ml of toluene and 11.8 ml of pyridine were added to the reaction mixture cooled to room temperature to make a homogeneous solution, and the optically active 1-methylheptyl 4'- was added thereto.
Hydroxybiphenyl-4-carboxylate 37.9
170 ml of a toluene solution containing g was added dropwise over 30 minutes while stirring. After this, the reaction was completed by stirring overnight at room temperature.

The reaction mixture was filtered to remove the precipitated pyridine salt. Next, the filtrate was placed on a rotary evaporator and the solvent was distilled off under reduced pressure at a bath temperature of 50 ° C. to obtain 79.8 g of a concentrate. After this, add 80 to this concentrate.
g of methylene chloride was added and stirred to prepare a uniform and transparent solution. The solution was fractionated by liquid chromatography using a pre-column packed with activated alumina and a main column packed with silica gel. The eluate containing the target substance is put on a rotary evaporator under reduced pressure to 50
The solvent was distilled off at a bath temperature of ° C to obtain 69.2 g (yield 88%) of a desired crude product of the diene compound (4).
Transfer the crude product to a 1 liter flask and
0 ml of ethanol was added. Next, a reflux condenser was attached to the flask and stirred at 70 ° C. for 10 minutes. After confirming that the white solid was completely dissolved into a uniform solution, the flask was naturally cooled to near room temperature. Then, the flask was stoppered to prevent moisture from entering, and then placed in a refrigerator and allowed to stand for 4 hours or more. After this, the flask was taken out, the precipitated white solid was collected by suction filtration, and washed with ethanol several times. Finally, this solid was dried overnight in a vacuum dryer at 50 ° C. to obtain the desired diene compound (4). The yield was 57.8 g (yield 74
%)Met.

This diene compound exhibits liquid crystallinity and exhibits the following phase transition behavior and physical property values.

-Polyaddition Reaction- The above-obtained diene compound (4) (57.8 g) and tetramethyldisiloxane (7.6 g) were dissolved in toluene (430 ml), and chloroplatinic acid hexahydrate (6) was further added in an argon gas stream.
mg was added as a catalyst and reacted at 80 ° C. for 8 hours. After completion of the reaction, the reaction mixture was allowed to stand at room temperature, 1.3 g of activated carbon was added to the reaction mixture, and the mixture was stirred at 50 ° C. for 10 minutes, and then filtered to remove the activated carbon. Toluene was distilled off from the reaction mixture under reduced pressure, and the residue was purified by silica gel column chromatography to obtain 50.3 g of the desired liquid crystalline copolymer A. The molecular weight, phase transition temperature and response time of the obtained copolymer are shown below.

Synthesis Example 2 Synthesis of Liquid Crystalline Copolymer B

Embedded image

[Chemical 31] Carboxylic acid derivative (3) 4 obtained in Synthesis Example 1- [3]
0 g and 30.5 g of optically active 1-methylbutyl 4'-hydroxybiphenyl-4-carboxylate were used, and the same diene compound (5) 4 was prepared as in Synthesis Example 1.
4.4 g was obtained. This diene compound exhibits liquid crystallinity and exhibits the following phase transition behavior and physical properties.

-Polyaddition reaction- 44.4 g of the diene compound (5) obtained above and 6.2 g of tetramethyldisiloxane were dissolved in 330 ml of toluene, and chloroplatinic acid hexahydrate was further added in an argon gas stream. 5 mg is added as a catalyst and reacted at 80 ° C. for 8 hours.
The same treatment and purification as in Synthesis Example 1 were carried out to obtain 36.5 g of the target liquid crystalline copolymer [B]. The molecular weight, phase transition temperature and response time of the obtained copolymer are shown below.

Reference Example 1 Synthesis of non-liquid crystal chiral compound C

Embedded image 60% by weight of oily NaH is added to 4 ml of DMF. Then 2- (4-hydroxyphenyl) -5- (1- (S)
-Methylbutoxy) pyrimidine 2.07 g of DMF16
Add ml solution and stir at room temperature for 15 minutes. After confirming that the generation of hydrogen gas has stopped, a solution of 2.99 g of dodecyl bromide in 4 ml of DMF is added dropwise. After stirring for 8 hours at room temperature, the reaction mixture is poured into 100 ml of water. Dilute hydrochloric acid is added to acidify, and the mixture is extracted with methylene chloride. The organic layer is dried over magnesium sulfate and the solvent is distilled off on a rotary evaporator. The residue was purified by column chromatography to obtain 2.87 g of the desired product (yield 84%).

NMR data of this compound [δ (ppm)]
Is as follows. 8.34 (s, 2H), 8.25 (d, 2H), 6.9
3 (d, 2H), 4.2 to 4.6 (m, 1H), 3.
98 (t, 2H), 2.0 to 0.5 (m, 3H)

[0047]

[Table 1]

Example 1 From the ferroelectric copolymer B synthesized in Synthesis Example 2 and the non-liquid crystal chiral compound C synthesized in Reference Example 1, C was prepared by the following method.
A ferroelectric resin composition having a content of 30% by weight was prepared. That is, ferroelectric liquid crystal copolymer B 0.7 g and non-liquid crystal chiral compound C 0.3 g were added to dichloromethane 10 ml.
To obtain a uniform solution. The solvent was distilled off with a rotary evaporator and further dried with a vacuum pump to completely remove the solvent, thereby obtaining a desired ferroelectric liquid crystal composition. The phase transition behavior (temperature lowering process) of this liquid crystal composition was judged by observation with a polarizing microscope, and the results were as shown below.

Although an isotropic phase and a liquid crystal phase coexist at 42 to 83 ° C., no disorder of orientation due to partial crystallization was observed in the SmC ^* phase temperature range of -15 to 42 ° C. Further, the response time of this ferroelectric liquid crystal composition to an electric field was measured and was 12 ms at 25 ° C. and 2.
It was 8 ms. Tilt angle (2θ) at 25 ° C
Was 42 °.

Example 2 From the ferroelectric liquid crystal copolymer B (0.5 g) used in Example 1 and the non-liquid crystal chiral compound C (0.5 g), a C content of 50% by weight was determined by the same method as in Example 1. Liquid crystal composition was prepared. The phase transition behavior (temperature lowering process) of this liquid crystal composition was judged by observation with a polarizing microscope, and the results were as shown below.

Although an isotropic phase and a liquid crystal phase coexist at 17 to 67 ° C., a phase separation state such as partial crystallization does not occur in the SmC ^* phase temperature range of −20 to 17 ° C.
No disorder of orientation was observed due to partial crystallization.
The tilt angle (2θ) at 25 ° C. was 13 °.

Example 3 From the ferroelectric liquid crystal copolymer B 0.3 g used in Example 1 and the non-liquid crystal chiral compound C 0.2 g, the ferroelectric composition containing 70% by weight of C in the same manner as in Example 1 was used. Liquid crystal composition was prepared. The phase transition behavior (temperature lowering process) of this liquid crystal composition was judged by observation with a polarizing microscope, and the results were as shown below.

Although an isotropic phase and a liquid crystal phase coexist at 12 to 49 ° C., a phase separation state such as partial crystallization does not occur in the SmC ^* phase temperature range of −25 to 12 ° C.
No disorder of orientation was observed due to partial crystallization.
Further, the tilt angle (2θ) at 25 ° C. was 5 °.

As is clear from Examples 1 to 3, when the non-liquid crystal chiral compound component increases, the tilt angle decreases. In order to obtain good contrast, the content of the non-liquid crystal chiral compound component is appropriately 20 to 40% by weight.

Example 4 D: Non-liquid crystal chiral compound represented by the following formula (described in Proceedings of 12th Liquid Crystal Symposium, 1986, 102)

[Chemical 33] A ferroelectric liquid crystal composition having a D content of 20 wt% was prepared from the ferroelectric liquid crystal copolymer B 0.8 g used in Example 1 and the non-liquid crystal chiral compound D 0.2 g by the same method as in Example 1. did. The phase transition behavior (temperature lowering process) of this liquid crystal composition was judged by observation with a polarizing microscope, and the results were as shown below.

In the SmC ^* phase temperature range, phase separation such as partial crystallization did not occur, and disorder of orientation due to partial crystallization was not observed. Further, the response time of this ferroelectric liquid crystal composition to an electric field was measured and found to be 23 ms at 25 ° C.

Example 5E: Non-liquid crystal chiral compound represented by the following formula (described in Proceedings of 58th Annual Meeting of the Chemical Society of Japan, 1989, 1865)

Embedded image

A ferroelectric liquid crystal composition having an E content of 40% by weight was prepared in the same manner as in Example 1 from 0.6 g of the ferroelectric liquid crystal copolymer A synthesized in Synthesis Example 1 and 0.4 g of the non-liquid crystal chiral compound E. The thing was prepared. The phase transition behavior (temperature lowering process) of this liquid crystal composition was judged by observation with a polarizing microscope, and the results were as shown below.

In the SmC ^* phase temperature range, a phase separation state such as partial crystallization did not occur, and disorder of orientation due to partial crystallization was not observed. The response time of this ferroelectric liquid crystal composition to an electric field was measured and found to be 11 ms at 25 ° C.

Example 6 F: Non-liquid crystal chiral compound represented by the following formula (described in Proceedings of 15th Liquid Crystal Symposium, 1989, 34)

Embedded image A ferroelectric liquid crystal composition containing 20% by weight of F was prepared by the same method as in Example 1 from 0.8 g of the ferroelectric liquid crystal copolymer A used in Example 5 and 0.2 g of the non-liquid crystal chiral compound F. did. The phase transition behavior (temperature lowering process) of this liquid crystal composition was judged by observation with a polarizing microscope, and the results were as shown below.

In the SmC ^* phase temperature range, phase separation such as partial crystallization did not occur, and disorder of orientation due to partial crystallization was not observed. Further, the response time of this ferroelectric liquid crystal composition to an electric field was measured and found to be 16 ms at 70 ° C.

[0062]

EFFECT OF THE INVENTION The ferroelectric liquid crystal composition of the present invention exhibits ferroelectricity in a wide temperature range including room temperature, has excellent film-forming properties, is less likely to undergo phase separation, and has good orientation. It exhibits the excellent property that the orientation is not easily disturbed, and its industrial value is extremely large in the field of optoelectronics.

Claims (1)

[Claims] 1. A repeating unit represented by the following general formula: [In the Formula, r and p are integers of 2-5, q is an integer of 0-3,
m is an integer of 1 to 20, and R ¹ is Is. However, R ² is -COOR ³ , -OR ³ or-.
OCOR ³ and R ³ is R ⁴ and R ⁵ are —CH ₃ or a halogen atom, and a, d
Is an integer of 0 to 10 and b is 0 or 1 (d is not 0 when R ⁵ is —CH ₃ ). ] And a liquid crystal copolymer [A] in which the molar ratio of [I] and [II] is approximately 1: 1 and a non-liquid crystal chiral compound [B].