JPH08143865A - Dichroic coloring matter, liquid crystal composition and liquid crystal element containing the same coloring matter - Google Patents

Abstract

PURPOSE: To obtain the subject coloring matter, containing a specific perfluoroalkylsulfonyl group, having a yellow to a blue color and further high dichroism and tinting strength and capable of constituting a liquid crystal element excellent in contrast and durability. CONSTITUTION: A coloring matter of formula I [B is H or a nonionic substituent group; X is formula II or III; Z<1> to Z<13> are each H, a halogen, methyl, methoxy or trifluoromethyl; Z<1> and Z<2> , Z<4> and Z<5> , Z<7> and Z<8> or Z<10> and Z<11> may mutually be bound to form an aliphatic ring or a (nitrogen-containing) aromatic ring; (n) is 1-18; (m) is 0-2; (p) is 0 or 1]. For example, anilines of formula IV containing a perfluoroalkylsulfonyl group are preferably used to afford the objective coloring matter according to the well-known diazotization coupling reaction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel yellow to blue azo dichroic dye, a liquid crystal composition containing the same and a liquid crystal device.

[0002]

2. Description of the Related Art At present, liquid crystal elements include twisted nematic (TN) type display mode and super twisted (ST) type.
Various display modes other than the N) mode have been proposed. Of these, a guest-host (GH) type display method in which a dye is dissolved in liquid crystal is widely used as a display panel for automobiles and the like because of its characteristics such as a wide viewing angle.

The properties of the dichroic dye used in the GH mode are required to be excellent in the following items: 1) dichroism 2) solubility 3) light resistance 4) coloring power.

On the other hand, the yellow, red to blue dichroic dyes necessary for constructing a black liquid crystal composition, which has a great market need, conventionally have an alkyl group, a nitro group or a cyano group at the terminal. Structural dyes are known. However, conventional dyes having a nitro group or a cyano group have great drawbacks in light resistance and solubility, and a dye having an alkyl group is apt to have a pale hue such as yellowish red and a deep color such as blue. It had a drawback that it was difficult to obtain a hue. Further, the conventional dye has a problem that the affinity such as solubility with respect to the fluorine-based liquid crystal used in the recent TFT liquid crystal element is not sufficient.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a dichroic dye having less of the above problems, a liquid crystal composition containing the same and a liquid crystal device.

[0006]

The object of the present invention is to provide a compound represented by the following general formula [I]

[0007]

Embedded image

(In the formula, B represents a hydrogen atom or a nonionic substituent, and X represents

[0009]

[Chemical 4]

Indicating Z¹~ Z¹³Are hydrogen atoms,
Halogen atom, methyl group, methoxy group or trifluoro
A methyl group, and Z¹And Z², Z^FourAnd Z^Five, Z
⁷And Z ⁸, Z^TenAnd Z¹¹Are linked to each other by an aliphatic ring, aromatic
A group ring or a nitrogen-containing aromatic ring may be formed, and n is 1 to 1
8, m is 0 to 2, and p is 0 or 1. )
Perfluoroalkylsulfonyl group, containing azo type
A dichroic dye, a liquid crystal composition containing the same, and a liquid crystal device
Achieved.

The azo dichroic dye used in the present invention has the following reaction formula [II]

[0012]

Embedded image

According to the method described above, the aniline having a perfluoroalkylsulfonyl group to be synthesized can be used to apply a known diazotized coupling reaction. B in the general formula [I] shown above represents a hydrogen atom or a nonionic substituent, and specific examples of the nonionic substituent include

[0014]

[Chemical 6]

And the like, R ¹ and R ² each represent a linear or branched alkyl group, R ³ represents an alkyl group containing at least one halogen atom, and R ⁴ and R ⁵
Each represents a hydrogen atom, a halogen atom, a methyl group, a methoxy group, a trifluoromethyl group, a nitro group or an alkyl group. X is

[0016]

[Chemical 7]

Is shown. Z ^{1 to} Z ¹³ each represent a hydrogen atom, a chlorine atom, a fluorine atom, a halogen atom such as a bromine atom, a methyl group, a methoxy group or a trifluoromethyl group, and Z ¹ and Z ² , Z ⁴ and Z ⁵ , Z ⁷ and Z ⁸ or Z ¹⁰ and Z ¹¹ are connected to each other to form an aliphatic ring such as a part of tetralin ring, an aromatic ring such as a part of naphthalene ring, or a nitrogen-containing aromatic ring such as a part of quinoline ring. May be formed.

N is 1 to 18, preferably 1 to 8 and m is 0.
˜2, preferably 1, p represents 0 or 1, preferably 0. When m is 2, Z ^{1 s} , Z ^{2 s,} or Z ^{3 s} that are substituted by different benzyl groups may be different from each other.

The liquid crystal composition of the present invention comprises an azo dichroic dye represented by the general formula [I] shown above [Liquid Crystal Device Handbook; Japan Society for the Promotion of Science, 142nd Committee (1989);
p154 to p192, p715 to p722] and a liquid crystal substance such as a biphenyl-based, phenylcyclohexane-based, phenylpyrimidine-based, cyclohexylcyclohexane-based liquid crystal compound or a liquid crystal composition exhibiting a nematic or smectic phase is mixed by a known method. Can be easily prepared. Examples of the liquid crystal compound used in the present invention are as follows.

[0020]

Embedded image

(In the formula, V and W are each an alkyl group, an alkoxy group, an alkoxyalkyl group, an alkylphenyl group, an alkoxyalkylphenyl group, an alkoxyphenyl group, an alkylcyclohexyl group, an alkoxyalkylcyclohexyl group, an alkylcyclohexylphenyl group, Cyanophenyl group, cyano group, halogen atom,
Represents a fluoromethyl group, a fluoromethoxy group, an alkylphenylalkyl group, an alkoxyalkylphenylalkyl group, an alkylcyclohexylalkyl group, an alkoxyalkoxycyclohexylalkyl group, an alkoxyphenylalkyl group or an alkylcyclohexylphenylalkyl group, and these alkyl chains and alkoxy chains It may have an optically active center therein. Y is a hydrogen atom,
Represents a halogen atom or a cyano group, and V and W
The phenyl group or phenoxy group therein may be further substituted with a halogen atom such as a cyano group, a fluorine atom or a chlorine atom. The phenyl group in each of the above structural formulas is 1
From 4 to 4 halogen atoms such as fluorine and chlorine,
It may be further substituted with a cyano group. )

The liquid crystal composition of the present invention contains an optically active compound such as cholesteryl nanoate, which may or may not exhibit a liquid crystal phase, and various additives such as an ultraviolet absorber and an antioxidant. Is also good. An element applying the guest-host effect by sandwiching the liquid crystal composition thus obtained between substrates with at least one of which is transparent [Shouichi Matsumoto, Ichino Tsunoda “Latest Liquid Crystal Technology” Industrial Research Meeting,
34 (1983): J. L. Fergason, SID
85 Digest, 68 (1985), etc.] and the like.

An example of a concrete display device is shown in FIGS. 1 shows the state when no voltage is applied, and FIG. 2 shows the state when no voltage is applied. In each figure, 1 is an observer, 2 is a transparent substrate, 3 is a transparent electrode subjected to parallel alignment treatment, and 4 and 5 are the present invention Liquid crystal composition, 4 is a nematic liquid crystal molecule having a positive dielectric anisotropy, 5 is a dichroic dye molecule, 9 is incident light, 8 is a polarizing plate, 7 is its polarization direction, and 6 is Represents incident polarization.
In this element, when no voltage is applied, the molecular long axes of the liquid crystal and the dichroic dye are parallel to the substrate, so that the element is in a colored state. On the other hand, at the time of application, the long axis direction is perpendicular to the substrate, so that it is in a colorless state.

[0024]

The dichroic dye having high dichroism and high coloring power of the present invention and the liquid crystal composition containing the same can form a liquid crystal element such as a display element excellent in contrast and durability. .

[0025]

EXAMPLES The present invention will be described in more detail with reference to the following examples. The present invention is not limited to the following examples unless it exceeds the gist. Example 1 Monoazo compound containing perfluoroethylsulfonyl group represented by the following structural formula

[0026]

[Chemical 9]

0.43 g (1.0 mmol) of acetic acid 8 m
1, dissolved in 5 ml of propionic acid, cooled to 0-5 ° C.,
0.44 g of 43% nitrosylsulfuric acid was added with stirring and reacted at this temperature for 1 hour to prepare a diazo solution. On the other hand, the following coupler

[0028]

[Chemical 10]

0.50 g was dissolved in 50 ml of methanol, cooled to 0-5 ° C., and diazo solution was gradually added with stirring,
Ammonia water was added to adjust the pH to 4, and the mixture was reacted at the same temperature for 2 hours. After the reaction, the precipitate was collected by filtration and purified by column chromatography to obtain 0.22 g of the dye having the following structural formula.

[0030]

[Chemical 11]

This azo dye is called as ZLI-1565 under the trade name.
A blue guest-host liquid crystal composition was prepared by dissolving it in a phenylcyclohexane-based liquid crystal mixture marketed as (E. MERCK) at a concentration of 0.2 wt%. A glass substrate with a transparent electrode, which was coated with a polyimide resin, cured and rubbed, faced, and was sealed in a cell having a gap of 9 μm so that the liquid crystal was aligned in parallel.

The absorbance for linearly polarized light parallel to the alignment direction (A _// ) and the absorbance for linearly polarized light perpendicular to the alignment direction (A⊥) of this blue-colored cell were measured, and the absorption peak (λ _max : 602 nm) was measured. ) The order parameter (S) in

[0033]

[Formula 1] As a result of obtaining from S = (A _// −A⊥) / (A _// −2A⊥), S = 0.75.

In the same manner as described above, an order parameter was determined using a fluorine-based liquid crystal mixture marketed under the trade name ZLI-4792 (manufactured by E. MERCK) instead of the above ZLI-1565. As a result, S = 0. 77 (λ _max : 59
4 nm).

Example 2 Phenylcyclohexane type liquid crystal mixture of azo compound obtained by the method according to Example 1: Trade name ZLI-15
Table 1 shows the order parameter (S) and hue in 65 (manufactured by E. MERCK). In the table,

[0036]

[Chemical 12]

Represents a trans form.

[0038]

[Table 1]

[0039]

[Table 2]

[0040]

[Table 3]

[0041]

[Table 4]

[0042]

[Table 5]

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a liquid crystal element according to the present invention in a state in which no voltage is applied.

FIG. 2 shows a schematic cross-sectional view of a voltage applied state of a liquid crystal element according to the present invention.

[Explanation of symbols]

 1 Observer 2 Transparent substrate 3 Transparent electrode subjected to parallel alignment treatment 4 Nematic liquid crystal molecule with positive dielectric anisotropy 5 Dichroic dye molecule 6 Incident polarization 7 Polarization direction of incident polarization 8 Polarizing light 9 Incident light

Claims (3)

[Claims] 1. A compound represented by the general formula [I]:(In the formula, B represents a hydrogen atom or a nonionic substituent,
X is, Z¹~ Z¹³Are hydrogen atom and halogen atom respectively
Child, methyl group, methoxy group or trifluoromethyl group
, And also Z¹And Z², Z^FourAnd Z^Five, Z⁷And Z ⁸,
Z^TenAnd Z¹¹Are linked to each other by an aliphatic ring, an aromatic ring or
A nitrogen-containing aromatic ring may be formed, n is 1 to 18 and m is 0.
˜2, p is a number of 0 or 1. )
Containing a perfluoroalkylsulfonyl group characterized by
Azo-based dichroic dye. 2. A liquid crystal composition comprising a liquid crystal substance and the azo-based dichroic dye having a perfluoroalkylsulfonyl group according to claim 1. 3. A liquid crystal device using the liquid crystal composition according to claim 2.