JPS6334852B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel liquid crystal material exhibiting positive dielectric anisotropy and a liquid crystal composition containing the same. Liquid crystal display elements utilize the optical anisotropy and dielectric anisotropy of liquid crystal materials, and depending on the display format, there are TN type (twisted nematic type), DS type (dynamic scattering type), and guest type. There are various types such as host type and DAP type, and the properties of the liquid crystal materials suitable for each type of use are different. However, it is common for all liquid crystal compositions to be stable against moisture, air, heat, light, etc., and they are also required to exhibit a liquid crystal phase over as wide a temperature range as possible, centered around room temperature. It is being However, at present, there is no single compound that satisfies these conditions, and the current situation is to use liquid crystal compositions obtained by mixing several types of liquid crystal compounds and non-liquid crystal compounds. In particular, recently there has been a demand for liquid crystal display elements that operate over a wider temperature range, and as a result, the liquid crystal used therein has also become required to exhibit a liquid crystal phase even in a higher temperature range. An object of the present invention is thus to provide a novel liquid crystal compound useful as a component constituting a liquid crystal having a wider liquid crystal temperature range. That is, the present invention is based on the general formula (In the above formula, R represents an alkyl group having 1 to 10 carbon atoms) trans-4-alkylcyclohexylmethyl-4'-(4''-fluorophenyl) phenyl ether and at least 1
A liquid crystal composition characterized by containing the following components. The compound of formula () of the present invention exhibits a liquid crystal phase up to a considerably high temperature, and by adding this compound as one component or replacing a certain component in the liquid crystal composition with this compound, a wider nematic temperature range can be obtained. A liquid crystal composition having the following properties can be obtained. Next, to outline the method for producing the compound of formula () of the present invention, 4-fluoro-4'-hydroxybiphenyl is dissolved in diethylene glycol monomethyl ether, and 1.1 to 1.2 times equivalent of 2N aqueous sodium hydroxide solution is added to the solution. and trans-1-alkyl-4-α
- Add bromomethylcyclohexane and heat under reflux for 3 hours to obtain the desired product. Showing this as a chemical formula: 4-Fluoro-4'-hydroxybiphenyl, one of the raw materials, is produced by the following process, details of which can be found in the specification of Japanese Patent Application No. 55-141537 filed by the present applicant. It is detailed in. In addition, trans-1-alkyl-4-α-bromomethylcyclohexane, which is another raw material, is produced by the following process, the details of which can be found in the specification of Japanese Patent Application No. 55-94220 filed by the present applicant. It is written in the book. EXAMPLES The following Examples show more specifically the manufacturing method and usage examples of the compounds of the present invention. Examples 1 to 6 [Production of trans-4-alkylcyclohexylmethyl-4′-(4″-fluorophenyl) phenyl ether] 4-fluoro-4′-hydroxybiphenyl 2.0
Dissolve g (0.0106 mol) in 30 ml of diethylene glycol monomethyl ether, add 6 ml (0.012 mol) of 2N aqueous sodium hydroxide solution, and shake to make a homogeneous solution. Next, trans-1-alkyl-4-α-bromomethylcyclohexane
Add 0.012 mol, heat under reflux with a mantle heater for 3 hours, cool to room temperature, pour into 50 ml of water,
Extract it with 150ml of toluene. toluene layer
After washing with 6N hydrochloric acid and then with a 2N aqueous sodium hydroxide solution, the solution is washed with water until neutral, dried over anhydrous sodium sulfate, and the toluene is distilled off under reduced pressure. When the remaining solid is recrystallized with ethanol, the desired trans-4-alkylcyclohexylmethyl-4′-(4″-fluorophenyl) phenyl ether is obtained. Its yield, phase transition point, and elemental analysis values etc. are shown in Table 1.

[Table] That is, those in which R has 2 to 5 carbon atoms are smectic liquid crystals, and those in which R has 6 or 7 carbon atoms exhibit both a smectic phase and a nematic phase. Example 7 (Application example) Trans-4-propyl-(4'-cyanophenyl)cyclohexane 28% Trans-4-pentyl-(4'-cyanophenyl)cyclohexane 43% Trans-4-heptyl-(4'-cyanophenyl)cyclohexane The nematic temperature range of a liquid crystal composition with a composition of 29% is
The temperature is 33-52°C, the dielectric anisotropy value is +10.5, the threshold voltage in TN cell is 1.53V, and the saturation voltage is 2.12V.
The nematic temperature range of a liquid crystal composition obtained by adding 15 parts of trans-4-hexylmethyl-4'-(4''-fluorophenyl) phenyl ether, which is a compound of the present invention, to 85 parts of this liquid crystal composition is -5 to The range was particularly high at 62°C, and the dielectric anisotropy value was +9.8, the threshold voltage was 1.50V, and the saturation voltage was 2.20V, which was slightly lower.

Claims (1)

[Claims] 1. General formula (In the above formula, R represents an alkyl group having 1 to 10 carbon atoms) trans-4-alkylcyclohexylmethyl-4-(4″-fluorophenyl) phenyl ether. 2 General formula (In the above formula, R represents an alkyl group having 1 to 10 carbon atoms) at least one component of trans-4-alkylcyclohexylmethyl-4'-(4''-fluorophenyl) phenyl ether A liquid crystal composition comprising: