JP2000080366A - Liquid crystal composition and liquid crystal optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a composition having a sufficiently low viscosity and a low threshold voltage by incorporating at least one trifluoroethylene compound. SOLUTION: The objective liquid crystal composition comprises 0.5-80 pts.wt., based on 100 pts.wt. of the composition, of a trifluoroethylene compound represented by the formula such as 2-[trans-4-(trans-4-cyclohexyl) cyclohexyl]-1,1,2-trifluoroethylene or the like. The liquid crystal composition is held between substrates equipped with an electrode by injection into a liquid crystal cell or by another method to give a liquid crystal optical element. In the formula, Y is hydrogen, R or RO; R is 1-10C monovalent aliphatic hydrocarbon which may have an ethereal oxygen inserted; A is Cya, Cyb, Cyc, Pha, Phb, Phc, Phd, 1,4-cyclohexenylene or the like; Cya is trans-1,4-cyclohexylene or the like; Cyb is trans-1,4-cyclohexylene with a CH2 portion substituted by oxygen, sulfur or the like; Pha is 1,4-phenylene; and Phb is halogen, methyl, cyano- substituted 1,4-phenylene or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to 1,1,2-trifluoro-2- (trans-4-substituted cyclohexyl)
The present invention relates to a liquid crystal composition containing an ethylene compound, and a liquid crystal optical element using the liquid crystal composition.

[0002]

2. Description of the Related Art Liquid crystal optical elements include display devices for OA equipment, display devices for home electric appliances, automotive instruments, measuring instruments, and the like.
It is used for various applications such as calculators and cameras, and various performance requirements such as a wide operating temperature range, low driving voltage, high-speed response, and chemical stability are required.

The performance of a liquid crystal optical element largely depends on the properties of a liquid crystal sandwiched between substrates of the element. However, when a liquid crystal optical element is used, there is no compound that satisfies all of the above requirements alone, and a liquid crystal composition obtained by mixing one or more other liquid crystal compounds and / or non-liquid crystal compounds with a liquid crystal compound. It satisfies the performance as a thing. Therefore, development of a liquid crystal composition in which one or more of the above-mentioned properties are improved according to the use of the liquid crystal optical element is desired.

[0004] In particular, recently, low driving voltage and high-speed responsiveness for battery-powered applications, high-definition display and high-speed responsiveness for OA equipment and the like, and wide operating temperature range and high-speed responsiveness at low temperatures for automotive instruments are called. As described above, it is required to improve the high-speed response, that is, the response speed of the liquid crystal optical element, while improving or maintaining other conditions in many applications. In particular, since the response of the liquid crystal tends to be remarkably reduced at a low temperature, its improvement is an important issue.

[0005] As a countermeasure, compounds having a halogen-substituted ethylene group at the terminal thereof have been studied (Japanese Patent Application Laid-Open No. Hei 6-50).
[0343] However, the compounds specifically described therein have problems such as that a sufficiently low threshold voltage cannot be obtained and the viscosity is not sufficiently low.

[0006]

One of the methods for improving the response speed is to lower the viscosity of a liquid crystal composition. That is, when the viscosity of the liquid crystal composition decreases, the response speed generally increases, and the response at low temperatures also improves. However, a useful liquid crystal composition having sufficiently low viscosity has not been obtained.
In addition, the compound used for the liquid crystal composition has excellent compatibility with other liquid crystal compounds and non-liquid crystal compounds in addition to the above physical properties, is a compound that is chemically stable, and has a low threshold voltage. Etc. are also important. An object of the present invention is to provide a useful novel liquid crystal composition having a sufficiently low viscosity and a low threshold voltage, and a liquid crystal optical element using the composition, which exhibits high-speed response.

[0007]

According to the present invention, there is provided a novel liquid crystal composition which solves the above-mentioned problems, comprising at least one trifluoroethylene compound represented by the following formula (1): And a liquid crystal optical element using the same. ^{Y-A-Cy a -CF =} CF 2 ··· Formula 1 provided that the symbols in the formula 1, the following meanings. Y: hydrogen atom, R or RO. R: a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms which may have an etheric oxygen atom inserted between carbon-carbon single bonds. A: Cy ^a , Cy ^b , Cy ^c , Ph ^a , Ph ^b , Ph ^c , Ph
^d , a 1,4-cyclohexenylene group, a 1,4-bicyclo [2.2.2] octylene group or a 1,3-cyclobutylene group. Cy ^a : an unsubstituted trans-1,4-cyclohexylene group. Cy ^b : a trans-1,4-cyclohexylene group in which one or more CH ₂ moieties are substituted with an oxygen atom or a sulfur atom. Cy ^c : a trans-1,4-cyclohexylene group in which one or more CH moieties are substituted with a nitrogen atom. Ph ^a : an unsubstituted 1,4-phenylene group. Ph ^b : a 1,4-phenylene group in which one or more hydrogen atoms are substituted with a halogen atom, a methyl group or a cyano group. Ph ^c : a 1,4-phenylene group in which one or more CH moieties are substituted with a nitrogen atom. Ph ^d : a 1,4-phenylene group in which one or more CH moieties are substituted by nitrogen atoms and one or more other hydrogen atoms are substituted by halogen atoms, methyl groups or cyano groups.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present specification, an aliphatic hydrocarbon group is an aliphatic group composed of only carbon atoms and hydrogen atoms, and means an alkyl group, an alkenyl group, an alkynyl group and the like.

In the formula 1, Y represents a hydrogen atom, R or RO. R represents a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms in which an etheric oxygen atom may be inserted between a carbon-carbon single bond, and an etheric oxygen atom is present between the carbon-carbon single bond. Preferably, it is not inserted. R preferably has 1 to 6 carbon atoms, and preferably has a linear structure.

Preferred examples of R include an alkyl group, an alkenyl group, an alkynyl group, an alkoxyalkyl group, an alkenyloxyalkyl group, an alkynyloxyalkyl group, and an alkoxyalkenyl group. Examples of RO include an alkoxy group and an alkenyl group. Preferred examples include an oxy group, an alkynyloxy group, an alkoxyalkoxy group, an alkenyloxyalkoxy group, and an alkynyloxyalkoxy group. Specific examples of R and RO are preferably those described in Examples.

A in Formula 1 is Cy ^a , Cy ^b , Cy ^c , P
h ^a, Ph ^b, shows a Ph ^c, Ph ^d, 1,4-cyclohexenylene group, 1,4-bicyclo [2.2.2] octylene group or a 1,3-cyclobutylene group. As A, C
^{y a, Cy b, Ph a} , Ph b, Ph c, 1,4- cyclohexenylene group, 1,4-bicyclo [2.2.2] Preferably octylene group or 1,3-cyclobutylene group, especially Cy ^a , Ph ^a , Ph ^b or a 1,4-cyclohexenylene group is preferred. The trifluoroethylene compound represented by the formula 1 wherein A is Cy ^a , Ph ^a , Ph ^b or 1,4-cyclohexenylene group has low viscosity and low threshold voltage, and is easy to synthesize. Is preferred. When A in the formula 1 is a 1,4-cyclohexenylene group, the site bonding to Y may be 1-position or 4-position.

When A is Cy ^b , one or two CH ₂
Those in which a part is substituted by an oxygen atom are preferable, and specific examples thereof include a tetrahydropyran-2,5-diyl group,
A 3-dioxane-2,5-diyl group and a 1,4-dioxane-2,5-diyl group are preferred. A in the formula 1 is a tetrahydropyran-2,5-diyl group or 1,
In the case of a 3-dioxane-2,5-diyl group, the site to be bonded to Y may be 2-position or 5-position.

When A is Cy ^c , one or two CHs
Those in which a part is substituted by a nitrogen atom are preferable, and specific examples thereof include a piperidine-1,4-diyl group. When A in the formula 1 is a piperidine-1,4-diyl group, the site bonded to Y may be 1-position or 4-position.

When A is Ph ^b , the substituent is preferably a halogen atom or a cyano group. In the case of a halogen atom, a fluorine atom or a chlorine atom is preferred, and a fluorine atom is particularly preferred. The number of substituents is preferably one or two.

When A is Ph ^c , one or two CHs
Those in which a part is substituted by a nitrogen atom are preferable, and specific examples include a pyridine-2,5-diyl group and a pyrimidine-
Preferable examples include a 2,5-diyl group, a pyrazine-2,5-diyl group, and a pyridazine-3,6-diyl group. Equation 1
When A in the formula is a pyridine-2,5-diyl group or a pyrimidine-2,5-diyl group, the site bonding to Y is 2
Or 5th place.

When A is Ph ^d , one or two CHs
It is preferable that the moiety is substituted with a nitrogen atom and one of the other hydrogen atoms is substituted with a halogen atom or a methyl group.
Specific examples include preferably a 4-chloropyrimidine-2,5-diyl group or a 4-methylpyrimidine-2,5-diyl group. A in the formula 1 is a 4-chloropyrimidine-2,5-diyl group or a 4-methylpyrimidine-
In the case of a 2,5-diyl group, the site bonded to Y may be at the 2- or 5-position. Specific examples of A are preferably those described in Examples.

The trifluoroethylene compound represented by the formula 1 (hereinafter, the “trifluoroethylene compound represented by the formula 1” is also referred to as “compound (1)”) is known as an intermediate material of a liquid crystal compound ( JP-A-8-12604). On the other hand, the present invention relates to a liquid crystal composition containing the compound (1) and a liquid crystal optical element using the liquid crystal composition. Further, they have found that the liquid crystal composition containing the compound (1) has a very low viscosity, and the response speed of a liquid crystal optical element using the liquid crystal composition is remarkably improved. Compound (1) can be synthesized by a known method (JP-A-8-12604, JP-A-8-40952, etc.).

Since the compound (1) is a trifluorovinyl group having a high electronegativity at the terminal and containing many fluorine atoms, the compound (1) is compared with a compound having a difluorovinyl group described in JP-A-6-500433. This is useful because the threshold voltage of a liquid crystal display element can be reduced, and high-speed response is exhibited. In addition, Japanese Patent Publication No. 6-50034
In the synthesis method described in No. 3, it is difficult to synthesize the compound (1).

When compound (1) is used as a liquid crystal composition, one or more of compound (1) may be used in combination with another liquid crystal compound and / or
Alternatively, the mixture is mixed with a non-liquid crystal compound (hereinafter, “other liquid crystal compounds and non-liquid crystal compounds” are collectively referred to as “other compounds”) to obtain a liquid crystal composition. Compound (1) is chemically stable and has excellent compatibility with other compounds. Therefore, the structures of the other compounds can be appropriately selected depending on the application, required performance, and the like. The content of the compound (1) in the liquid crystal composition can be appropriately selected depending on the use, the purpose of use, the type of other compound, and the like.
It is preferably about 80 parts by weight, particularly preferably 2 to 30 parts by weight.

Examples of other compounds include compounds that improve dielectric anisotropy, compounds that exhibit liquid crystallinity at high temperatures, other low-viscosity compounds, compounds that adjust the value of refractive index anisotropy, and compounds that impart cholesteric properties. Examples include compounds, compounds exhibiting dichroism, and compounds imparting conductivity.

Specific examples of other compounds include the following compounds. R ¹ -X ¹ -X ² -R ² , R ¹ -X ¹ -C≡C-X ² -R ² , R ¹ -X ¹ -COO-X ² -R ² , R ¹ -X ¹ -CH = ^{CH-X 2 -R 2, R} 1 -X 1 -CF = CF-X 2 -R 2, R 1 -X 1 -X 2 -CF = CF-X 3 -R 2, R 1 -X 1 -CH _{^{2 CH 2 -X 2 -R 2,}} R 1 -X 1 -X 2 -CH 2 CH 2 -X 3 -R 2, R 1 -X 1 -X 2 -X 3 -R 2, R 1 -X 1 -X ² -C≡C-X ³ -R ² , R ¹ -X ¹ -X ² -X ³ -X ⁴ -R ² , R ¹ -X ¹ -COO-X ² -X ³ -R ² , R ^{1 -X 1 -X 2 -COO-X} 3 -R 2, R 1 -X 1 -COO-X 2 -COO-X 3 -R 2, R 1 -X 1 -COO-X 2 -OCO-X 3 -R ^2.

The symbols in the above formula have the following meanings.
R ¹ and R ² may be the same or different and each represents an alkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a halogen atom or a cyano group. X ¹ ,
X ² , X ³ , X ⁴ : may be the same or different, each represents a divalent ring group, and is preferably a 1,4-phenylene group or a trans-1,4-cyclohexylene group.
Note that the above compounds are examples, and various compounds may be appropriately selected according to desired performance.

The liquid crystal composition of the present invention is sandwiched between substrates with electrodes by, for example, injecting into a liquid crystal cell to form a liquid crystal optical element. The liquid crystal optical element is a TN (Twisted)
Nematic) method, STN (Super Twi)
Stable Nematic, IPS (In-Pl)
ane Switching, VA (Verti)
cal Alignment) method, GH (Guest)
-Host) mode, ferroelectric liquid crystal display mode, dynamic scattering mode, phase change mode, dual frequency drive mode, and various other modes can be used for display applications. TN as a representative
Liquid crystal optical element. It can also be used for applications other than display applications, such as dimming windows, optical shutters, polarization conversion elements, variable focus liquid crystal lenses, and variable focus diffractive optical elements. Further, it can be used for a method of writing by heat instead of electricity.

The structure of the liquid crystal optical element and a specific example of the manufacturing method will be described below. An undercoat layer such as SiO ₂ or Al ₂ O ₃ or a color filter layer is formed on a substrate such as plastic or glass, if necessary, to form an In ₂ O ₃ —SnO ₂ (IT
O), after providing electrodes such as SnO ₂ and patterning,
If necessary, polyimide, polyamide, SiO ₂ , Al ₂
An overcoat layer of O ₃ or the like is formed and an orientation treatment is performed. A seal material is printed thereon, the electrodes are arranged so as to face each other, the periphery is sealed, and the seal material is cured to form empty cells.

A liquid crystal composition containing the compound (1) is injected into the empty cell, and the injection port is sealed with a sealant to form a liquid crystal cell. If necessary, a polarizing plate, a color polarizing plate, a light source, a color filter, a semi-transmissive reflecting plate, a reflecting plate, a light guide plate, an ultraviolet cut filter, etc. are laminated on the liquid crystal cell, and characters,
A figure or the like is printed, subjected to non-glare processing or the like to form a liquid crystal optical element.

The above description is of the basic structure and manufacturing method of the liquid crystal optical element, and is based on the use of a substrate using two-layer electrodes, a two-layer liquid crystal cell having two liquid crystal layers, and a reflective electrode. Substrate, TFT, MIM (Metal Insul
Various configurations such as an active matrix element using an active matrix substrate on which an active element such as an attor metal is formed can be used.

[0027]

EXAMPLES Hereinafter, the present invention will be described with reference to Synthesis Examples (Examples 1, 2, 3, and 4).
4), Examples (Examples 5, 6, and 7) and Comparative Examples (Example 8).

Example 1 110 g of phosphorus pentachloride (0.532)
Mol) was added to 1 L of chloroform, cooled to -30 ° C or lower, and then 74.6 g of trans-4- (trans-4-propylcyclohexyl) cyclohexanol (0.
(333 mol) dissolved in 600 mL of chloroform was added dropwise over 1 hour at -30 ° C or lower with stirring, and further stirred at the same temperature for 30 minutes. Then add 5%
An aqueous solution of potassium carbonate was added dropwise, and after stirring at room temperature for 30 minutes, the organic layer was separated. After the aqueous layer was further extracted with chloroform, the chloroform layer was combined with the organic layer and washed with water, and the solvent was distilled off. The obtained crude liquid was purified by silica gel column chromatography to obtain 39.2 g of trans-1-chloro-4- (trans-4-propylcyclohexyl) cyclohexane (hereinafter, referred to as compound S).
(0.161 mol) was obtained.

4,4'-di-t-butylbiphenyl 9
After dissolving 0.1 g (0.338 mol) in 2400 mL of anhydrous tetrahydrofuran, the mixture was cooled to 0 ° C. Under an argon gas atmosphere, 8.9 g (1.3 mol) of lithium metal and 0.1 g of bromine were added, and the mixture was stirred at the same temperature for 3 hours. Then, the reaction solution was cooled to -70 ° C, and compound S3
A solution of 9.2 g (0.161 mol) dissolved in 100 mL of anhydrous tetrahydrofuran was added dropwise with stirring at -50 ° C or lower for 30 minutes, and further stirred at the same temperature for 2 hours. Next, 19 g (0.19 mol) of tetrafluoroethylene gas was blown into the reaction solution at −50 ° C. or lower over 15 minutes, and the mixture was further stirred at the same temperature for 30 minutes. Thereafter, the temperature was raised to room temperature, 300 mL of 10% diluted hydrochloric acid was added, extracted with hexane, washed with water and dried, and the solvent was distilled off.

The crude liquid obtained was distilled under reduced pressure, purified by silica gel column chromatography, and after distilling off the solvent, recrystallized three times with ethanol to obtain the desired 2- [trans-4- (trans-4). -Propylcyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene (formula 2: hereinafter, also referred to as compound (2)) 11.6 g
(0.040 mol).

[0031]

[Table 1]

Example 2 trans-4- (trans-4-propylcyclohexyl) cyclohexanol 7 of Example 1
Trans-4- instead of 4.6 g (0.333 mol)
The reaction was carried out in the same manner as in Example 1 using 79.3 g (0.333 mol) of (trans-4-butylcyclohexyl) cyclohexanol to give 2- [trans-4- (trans-4
-Butylcyclohexyl) cyclohexyl] -1,1,1
2-trifluoroethylene (formula 3: hereinafter, compound (3)
11.6 g (0.038 mol) was obtained.

[Table 2] Example 3 74.6 g of trans-4- (trans-4-propylcyclohexyl) cyclohexanol of Example 1
The reaction was carried out in the same manner as in Example 1 except that 84.1 g (0.333 mol) of trans-4- (trans-4-pentylcyclohexyl) cyclohexanol was used instead of (0.333 mol) to give 2- [trans-4 -(Trans-4-pentylcyclohexyl) cyclohexyl] -1,1,2-
21.8 g (0.069 mol) of trifluoroethylene (formula 4: hereinafter also referred to as compound (4)) was obtained.

[Table 3] Example 4 Using the corresponding 4-substituted cyclohexanol in place of trans-4- (trans-4-propylcyclohexyl) cyclohexanol of Example 1, reacting in the same manner as in Example 1 to obtain the following compounds Can be. 2-
[Trans-4- (trans-4-cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene,
2- [trans-4- (trans-4-methylcyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4-ethylcyclohexyl) cyclohexyl] -1,1,1 2-trifluoroethylene, 2- [trans-4- (trans-4-hexylcyclohexyl) cyclohexyl]-
1,1,2-trifluoroethylene, 2- [trans-
4- (trans-4-heptylcyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2-
[Trans-4- (trans-4-octylcyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4-nonylcyclohexyl) cyclohexyl] -1,1,2- Trifluoroethylene, 2- [trans-4- (trans-
4-decylcyclohexyl) cyclohexyl] -1,
1,2-trifluoroethylene.

2- [trans-4- (trans-4-methoxycyclohexyl) cyclohexyl] -1,1,2
-Trifluoroethylene, 2- [trans-4- (trans-4-ethoxycyclohexyl) cyclohexyl]
-1,1,2-trifluoroethylene, 2- [trans-4- (trans-4-propoxycyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene,
2- [trans-4- (trans-4-butoxycyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4-pentyloxycyclohexyl) cyclohexyl] -1,
1,2-trifluoroethylene, 2- [trans-4-
(Trans-4-hexyloxycyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene,
-[Trans-4- (trans-4-heptyloxycyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4
-Octyloxycyclohexyl) cyclohexyl]-
1,1,2-trifluoroethylene.

2- [trans-4- (trans-4-vinylcyclohexyl) cyclohexyl] -1,1,2-
Trifluoroethylene, 2- [trans-4- (trans-4- (trans-1-propenyl) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4- (Trans-1-butenyl) cyclohexyl) cyclohexyl]
-1,1,2-trifluoroethylene, 2- [trans-4- (trans-4- (trans-1-pentenyl)
Cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-
4- (trans-1-hexenyl) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene,
2- [trans-4- (trans-4- (trans-1
-Heptenyl) cyclohexyl) cyclohexyl]-
1,1,2-trifluoroethylene.

2- [trans-4- (trans-4-
(2-propenyl) cyclohexyl) cyclohexyl]
-1,1,2-trifluoroethylene, 2- [trans-4- (trans-4- (3-butenyl) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (Trans-4- (trans-3-pentenyl) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4- (4-pentenyl) cyclohexyl) cyclohexyl] -1 , 1,2-trifluoroethylene, 2- [trans-4- (trans-4-
(Trans-3-hexenyl) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2-
[Trans-4- (trans-4- (5-hexenyl)
Cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-
4- (trans-3-heptenyl) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene,
2- [trans-4- (trans-4- (trans-5
-Heptenyl) cyclohexyl) cyclohexyl]-
1,1,2-trifluoroethylene.

2- [trans-4- (trans-4-vinyloxycyclohexyl) cyclohexyl] -1,
1,2-trifluoroethylene, 2- [trans-4-
(Trans-4- (trans-1-propenyloxy)
Cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-
4- (trans-2-butenyloxy) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4- (trans-2-pentenyloxy) cyclohexyl) cyclohexyl] -1 , 1,2-trifluoroethylene, 2-
[Trans-4- (trans-4- (trans-2-hexenyloxy) cyclohexyl) cyclohexyl]-
1,1,2-trifluoroethylene, 2- [trans-
4- (trans-4- (trans-2-heptenyloxy) cyclohexyl) cyclohexyl] -1,1,2-
Trifluoroethylene, 2- [trans-4- (trans-4- (2-propenyloxy) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene,
2- [trans-4- (trans-4- (3-butenyloxy) cyclohexyl) cyclohexyl] -1,1,1
2-trifluoroethylene, 2- [trans-4- (trans-4- (4-pentenyloxy) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4 -(Trans-4-hexenyloxy) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2-
[Trans-4- (trans-4- (5-hexenyloxy) cyclohexyl) cyclohexyl] -1,1,2
-Trifluoroethylene, 2- [trans-4- (trans-4- (trans-4-heptenyloxy) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4 −
(6-Heptenyloxy) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene.

2- [trans-4- (trans-4-
(1-propynyl) cyclohexyl) cyclohexyl]
-1,1,2-trifluoroethylene, 2- [trans-4- (trans-4- (1-butynyl) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (Trans-4- (1-pentynyl) cyclohexyl) cyclohexyl] -1,
1,2-trifluoroethylene, 2- [trans-4-
(Trans-4- (1-hexynyl) cyclohexyl)
Cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-4- (1-heptynyl) cyclohexyl) cyclohexyl] -1,1,1
2-trifluoroethylene.

2- [trans-4- (trans-4-methoxymethylcyclohexyl) cyclohexyl] -1,
1,2-trifluoroethylene, 2- [trans-4-
(Trans-4-ethoxymethylcyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene,
-[Trans-4- (trans-4-propoxymethylcyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (trans-
4-butoxymethylcyclohexyl) cyclohexyl]
-1,1,2-trifluoroethylene, 2- [trans-4- (trans-4- (2-methoxyethoxy) cyclohexyl) cyclohexyl] -1,1,2-trifluoroethylene.

2- (trans-4-phenylcyclohexyl) -1,1,2-trifluoroethylene, 2- [trans-4- (4-methylphenyl) cyclohexyl]
-1,1,2-trifluoroethylene, 2- [trans-4- (4-ethylphenyl) cyclohexyl] -1,
1,2-trifluoroethylene, 2- [trans-4-
(4-propylphenyl) cyclohexyl] -1,1,1
2-trifluoroethylene, 2- [trans-4- (4
-Butylphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-pentylphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-hexylphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-heptylphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans- 4- (4-octylphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-nonylphenyl) cyclohexyl] -1,1,2-trifluoroethylene,
2- [trans-4- (4-decylphenyl) cyclohexyl] -1,1,2-trifluoroethylene.

2- [trans-4- (4-methoxyphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-ethoxyphenyl) cyclohexyl] -1,1,2 -Trifluoroethylene, 2- [trans-4- (4-propoxyphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-butoxyphenyl)
Cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-pentyloxyphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- Hexyloxyphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-heptyloxyphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4 -(4-octyloxyphenyl) cyclohexyl] -1,1,2-trifluoroethylene.

2- [trans-4- (4-vinylphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (trans-1-propenyl) phenyl) cyclohexyl] -1,1,2-
Trifluoroethylene, 2- [trans-4- (4-
(Trans-1-butenyl) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (trans-1-pentenyl) phenyl) cyclohexyl] -1,1,2- Trifluoroethylene, 2- [trans-4- (4- (trans-1-hexenyl) phenyl) cyclohexyl] -1,1,2-
Trifluoroethylene, 2- [trans-4- (4-
(Trans-1-heptenyl) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (2-propenyl) phenyl) cyclohexyl] -1,1,2-trifluoro Ethylene, 2-
[Trans-4- (4- (3-butenyl) phenyl) cyclohexyl] -1,1,2-trifluoroethylene,
2- [trans-4- (4- (trans-3-pentenyl) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (4-pentenyl) phenyl) cyclohexyl ] -1,1,2-
Trifluoroethylene, 2- [trans-4- (4-
(Trans-3-hexenyl) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (5-hexenyl) phenyl) cyclohexyl] -1,1,2-trifluoro Ethylene, 2-
[Trans-4- (4- (trans-3-heptenyl)
Phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (trans-
5-heptenyl) phenyl) cyclohexyl] -1,
1,2-trifluoroethylene.

2- [trans-4- (4-vinyloxyphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (trans-
1-propenyloxy) phenyl) cyclohexyl]-
1,1,2-trifluoroethylene, 2- [trans-
4- (4- (trans-2-butenyloxy) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (trans-2-pentenyloxy) phenyl) cyclohexyl]- 1,
1,2-trifluoroethylene, 2- [trans-4-
(4- (trans-2-hexenyloxy) phenyl)
Cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (trans-2-heptenyloxy) phenyl) cyclohexyl] -1,1,1
2-trifluoroethylene, 2- [trans-4- (4
-(2-propenyloxy) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (3-butenyloxy) phenyl) cyclohexyl] -1,1,2-trifluoro ethylene,
2- [trans-4- (4- (4-pentenyloxy)
Phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (trans-
4-hexenyloxy) phenyl) cyclohexyl]-
1,1,2-trifluoroethylene, 2- [trans-
4- (4- (5-hexenyloxy) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2-
[Trans-4- (4- (trans-4-heptenyloxy) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (6-
Heptenyloxy) phenyl) cyclohexyl] -1,
1,2-trifluoroethylene.

2- [trans-4- (4- (1-propynyl) phenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4- (1-
Butynyl) phenyl) cyclohexyl] -1,1,2-
Trifluoroethylene, 2- [trans-4- (4-
(1-pentynyl) phenyl) cyclohexyl] -1,
1,2-trifluoroethylene, 2- [trans-4-
(4- (1-hexynyl) phenyl) cyclohexyl]
-1,1,2-trifluoroethylene, 2- [trans-4- (4- (1-heptynyl) phenyl) cyclohexyl] -1,1,2-trifluoroethylene.

2- [trans-4- (4-methoxymethylphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-ethoxymethylphenyl) cyclohexyl] -1,1 , 2-Trifluoroethylene, 2- [trans-4- (4-propoxymethylphenyl) cyclohexyl] -1,1,2-trifluoroethylene, 2- [trans-4- (4-butoxymethylphenyl) cyclohexyl] -1,1,2-
Trifluoroethylene, 2- [trans-4- (4-
(2-methoxyethoxy) phenyl) cyclohexyl]
-1,1,2-trifluoroethylene.

Further, in the same manner,
1,2-trifluoro-2- (trans-4-substituted cycle
Rohexyl) ethylene compounds can be obtained. Lower formula
C inside _ThreeH₇Represents an n-propyl group, C_FiveH₁₁Is n-pliers
Shows the radical.

[0046]

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[0047]

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[0048]

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[0049]

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Example 5 Liquid crystal composition ZLI-1 manufactured by Merck
20 parts by weight of Compound (2) was added to 80 parts by weight of 565 to obtain Composition A. Composition A did not show any precipitation of crystals even when left at 0 ° C. for 10 days.

For the obtained composition A, the kinematic viscosity (0 ° C. and 25 ° C .: unit cSt), clearing point (NI transition temperature:
Unit, ° C), refractive index anisotropy value (Δn, 589 nm, 25
° C: no unit). Table 4 shows the results. The smaller the value of the kinematic viscosity, the lower the viscosity of the composition.

The response time (τ: unit ms) and threshold voltage (unit V) of the liquid crystal optical device using the composition A were measured by the following methods. Table 4 shows the results.

[Response Time and Threshold Voltage] An overcoat layer of SiO ₂ was formed on a substrate with an ITO electrode,
Composition A was sandwiched between the rubbed substrates to form a TN type liquid crystal cell having a substrate spacing of 8 μm. Using this liquid crystal cell, time-division driving with a 1/3 duty and 1/3 bias waveform by a conventionally known voltage averaging method is performed.
The response time (τ) and the threshold voltage were measured (measuring temperature 25 ° C.). The smaller the value of the response time (τ), the faster the response speed.

Example 6 Liquid crystal composition ZLI-1 manufactured by Merck & Co.
20 parts by weight of the compound (3) was added to 80 parts by weight of 565 to obtain a composition B. Composition B did not show any precipitation of crystals even when left at 0 ° C. for 10 days. The measurement was performed in the same manner as in Example 5. Table 4 shows the results.

Example 7 Liquid Crystal Composition ZLI-1 manufactured by Merck
20 parts by weight of Compound (4) was added to 80 parts by weight of 565 to obtain Composition C. Composition C did not show any precipitation of crystals even when left at 0 ° C. for 10 days. The measurement was performed in the same manner as in Example 5. Table 4 shows the results.

[Example 8] Liquid crystal composition ZLI-1 manufactured by Merck & Co.
Only 565 was Composition D. The measurement was performed in the same manner as in Example 5. Table 4 shows the results.

[0057]

[Table 4]

The viscosity of the liquid crystal composition to which the compound (2), the compound (3) and the compound (4) are added is greatly reduced at 0 ° C. and 25 ° C., and the response speed when the liquid crystal optical element is used is also remarkable. Improved. Further, a decrease in threshold voltage was also confirmed.

[0059]

The liquid crystal composition containing one or more compounds (1) has a very low viscosity, and the response speed of a liquid crystal optical element using the liquid crystal composition is remarkably improved.

Claims (3)

[Claims] 1. A liquid crystal composition comprising at least one trifluoroethylene compound represented by the following formula 1. ^{Y-A-Cy a -CF =} CF 2 ··· Formula 1 provided that the symbols in the formula 1, the following meanings. Y: hydrogen atom, R or RO. R: a monovalent aliphatic hydrocarbon group having 1 to 10 carbon atoms which may have an etheric oxygen atom inserted between carbon-carbon single bonds. A: Cy ^a , Cy ^b , Cy ^c , Ph ^a , Ph ^b , Ph ^c , Ph
^d , a 1,4-cyclohexenylene group, a 1,4-bicyclo [2.2.2] octylene group or a 1,3-cyclobutylene group. Cy ^a : an unsubstituted trans-1,4-cyclohexylene group. Cy ^b : a trans-1,4-cyclohexylene group in which one or more CH ₂ moieties are substituted with an oxygen atom or a sulfur atom. Cy ^c : a trans-1,4-cyclohexylene group in which one or more CH moieties are substituted with a nitrogen atom. Ph ^a : an unsubstituted 1,4-phenylene group. Ph ^b : a 1,4-phenylene group in which one or more hydrogen atoms are substituted with a halogen atom, a methyl group or a cyano group. Ph ^c : a 1,4-phenylene group in which one or more CH moieties are substituted with a nitrogen atom. Ph ^d : a 1,4-phenylene group in which one or more CH moieties are substituted by nitrogen atoms and one or more other hydrogen atoms are substituted by halogen atoms, methyl groups or cyano groups. Wherein A is Cy ^a, Ph ^a, Ph ^b and 1,4
The liquid crystal composition according to claim 1, which is a cyclohexenylene group. 3. A liquid crystal optical element using the liquid crystal composition according to claim 1.