JP3258682B2 - Liquid crystal composition containing m-methylbenzoic acid ester derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an m-methylbenzoate derivative useful as an electro-optical display material.
More particularly, a liquid crystal composition containing a useful m- methylbenzoic acid ester derived material to reduce the anisotropy ([Delta] n) of the refractive index of the liquid crystal material by mixing the nematic liquid crystal material.

[0002]

2. Description of the Related Art Liquid crystal display devices began to be used in displays such as watches and calculators, and are now widely used in pocket televisions, various displays and optoelectronic devices. However, most of such liquid crystal display elements are of a TN type display system, and a liquid crystal material belonging to a nematic phase is used.

[0003] Such a TN type display system is a light receiving element type, so that eyes are not tired even when used for a long time.
It has the advantages of being small and thin, and having low driving voltage and low power consumption.However, as the application field expands, the characteristics required for liquid crystal materials are diversified, and the anisotropy of the refractive index is increased. There has been a demand for a liquid crystal material that reduces (Δn).

It is therefore an object of the present invention is to provide a refractive index anisotropy ([Delta] n) Ru can be reduced of compound by blending the liquid crystal material.

[0005]

Means for Solving the Problems The present inventors have proposed the following chemical formula 2.
It has been found that the anisotropy (Δn) of the refractive index can be reduced by blending the m-methylbenzoic acid ester derivative represented by the general formula (I) (same as in Chemical formula 1) into a liquid crystal material. The present invention has been reached.

[0006]

Embedded image (In the formula, X represents -CN or a halogen atom, and Y represents a hydrogen atom or a halogen atom.)

Namely, the present invention is to provide a liquid crystal composition containing the m- methylbenzoic acid ester derived material represented by the above general formula (I).

Hereinafter, the present invention having the above gist will be described in detail.

In the above formula (I), the halogen atom represented by X or Y is a fluorine atom, a chlorine atom, a bromine atom,
Represents an iodine atom. Accordingly, as the m-methylbenzoic acid ester derivative of the present invention represented by the general formula (I), for example, compounds represented by the following formulas 3 to 4 (compounds 1 to 4)
2).

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Embedded image

The m- of the present invention represented by the above general formula (I)
The methyl benzoate derivative can be easily produced, for example, by esterifying m-methyl benzoic acid with a nucleus-substituted phenol.

By mixing the thus obtained m-methylbenzoic acid ester derivative of the present invention with a liquid crystal material (base liquid crystal), the refractive index anisotropy (Δn) of the liquid crystal material composition is obtained.
Can be reduced.

The compound constituting the mother liquid crystal includes, for example, a compound represented by the following chemical formula (5).

[0013]

Embedded image (Wherein R and R ′ are each a halogen atom, a hydroxyl group,
A nitro group, a cyano group, an alkyl group, an alkoxy group, an alkenyl group, an alkenyloxy group, a carboxy group or an alkoxycarbonyl group, R "represents a hydrogen atom or a halogen atom, and X represents -COO-, -OCO-,- CH = N-, -N = CH-,
-CH ₂ O-, -OCH _2- , -CH ₂ CH _2- , -CH = CH- or -O-, wherein rings A, B and C each represent a benzene ring, a cyclohexane ring or a pyrimidine ring; , B and c each represent 1 or 2. When the same symbol is present in the same molecule, they may be the same or different. )

The above-mentioned mother liquid crystals are usually used by mixing several or more of these compounds.
The liquid crystal composition of the present invention is prepared by mixing the m-methylbenzoic acid ester derivative of the present invention, preferably 1 to 30 parts by weight, with respect to 0 parts by weight.

[0015]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by the following examples.

Example 1 Synthesis of 3 ', 4'-difluorophenyl-3-methylbenzoate (compound 1 of the above formula 3)

1.36 g of m-toluic acid, 1.56 g of 3,4-difluorophenol and 2.47 g of dicyclohexylcarbodiimide were dispersed in 20 ml of dichloromethane, and the mixture was stirred at room temperature for 5 hours under an argon atmosphere to remove the formed dicyclohexylurea. After filtration, the solvent was distilled off under reduced pressure. The solvent removal residue was purified with ethyl acetate / n-hexane (10/9
Silica gel column treatment was carried out using 0) as a developing solvent to obtain 1.4 g of a colorless liquid.

As a result of infrared spectroscopy, the obtained reaction product (colorless liquid) had the following characteristic absorption and was confirmed to be the desired product.

2916 cm ^-1 , 1735 cm ^-1 , 161
^{2cm -1, 1502cm -1, 1268cm -1} , 1179
^{cm -1, 1134cm -1, 1055cm -1} , 728cm
^-1 , 594 cm ^-1

Example 2 Synthesis of 4'-cyanophenyl-3-methylbenzoate (compound 2 of the above formula 4)

1.36 g of m-toluic acid, 1.43 g of p-cyanophenol and 2.47 g of dicyclohexylcarbodiimide were dispersed in 20 ml of dichloromethane, and the mixture was stirred at room temperature for 5 hours under an argon atmosphere, and the formed dicyclohexylurea was filtered off. The solvent was distilled off under reduced pressure. The residue obtained by removing the solvent was subjected to silica gel column treatment using ethyl acetate / n-hexane (10/90) as a developing solvent.
1.5 g of white crystals at 2 ° C. were obtained.

As a result of infrared spectroscopy, the obtained reaction product (white crystal) had the following characteristic absorption and was confirmed to be the desired product.

3100 cm ^-1 , 2222 cm ^-1 , 172
^{2cm -1, 1594cm -1, 1495cm -1} , 1206
^{cm -1, 1082cm -1, 861cm -1} , 727c
m ^-1 , 547cm ^-1

Example 3 Effect when n-alkylcyanobiphenyl-based liquid crystal composition is used as mother liquid crystal

90 parts by weight of a commercially available n-alkyl cyanobiphenyl liquid crystal composition [52% by weight of 4-n-amyl-4'-cyanobiphenyl, 25% by weight of 4-heptyl-4'-cyanobiphenyl, 4-n- Octoxy-4′-cyanobiphenyl 15% by weight, 4-amyl-4′-cyanobiphenyl 8% by weight], and 10 parts by weight of the m-methylbenzoic acid ester derivative (compounds 1 and 2) of the present invention. Δn were measured respectively. Similarly, to 90 parts by weight of the liquid crystal composition, 10 parts by weight of a compound shown in the following Chemical Formula 6 (control product) was added, and Δn was measured. The results are shown in Table 1 below.

[0026]

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[0027]

[Table 1]

From the results of the above examples, it can be seen that the m-methylbenzoic acid ester derivative of the present invention has an excellent effect of reducing the anisotropy of the refractive index of the mother liquid crystal and has an advantage of having a wide viewing angle. Understand. Therefore, it is clear that the liquid crystal composition of the present invention is extremely useful as a liquid crystal material of a TN display mode.

[0029]

The m-methylbenzoic acid ester derivative of the present invention can reduce the anisotropy (Δn) of the refractive index by being incorporated into a liquid crystal material.

Continuation of front page (56) References JP-A-57-203592 (JP, A) C. Joshi et al. , Jour. Indian Chem. S oc. , 1960, Vol. 37, No. 11, p. 687-9 (58) Fields investigated (Int. Cl. ⁷ , DB name) C09K 19/20 C07C 69/773 C07C 255/55 C09K 19/46 CA (STN) CAOLD (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. The compound represented by the following general formula (I):
Contains at least one methyl benzoate derivative
Liquid crystal composition . Embedded image (In the formula, X represents -CN or a halogen atom, and Y represents a hydrogen atom or a halogen atom.)