JPH02269189A - Ferroelectric liquid crystal composition and ferroelectric liquid crystal display element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a ferroelectric liquid crystal composition, an alignment film for a ferroelectric liquid crystal element, a sealant for a ferroelectric liquid crystal element, and a ferroelectric liquid crystal display element.

In particular, the present invention relates to a ferroelectric liquid crystal composition 1 having excellent environmental stability, particularly thermal stability, an alignment film for a ferroelectric liquid crystal element, a sealing agent in a ferroelectric liquid crystal element, and a ferroelectric liquid crystal display element.

BACKGROUND OF THE INVENTION Display systems for liquid crystal display devices that are currently in widespread use are twisted nematic type (TN type) and dynamic scattering type (DS type). These are nematic liquid crystals,
This is a display using a nematic liquid crystal cell as the main component.

One of the disadvantages of conventional nematic liquid crystal cells is the fact that the response speed is slow, and a response speed of only a few m1eQ can be obtained at most. This is one of the factors that limits the range of applications of nematic liquid crystal cells. However, it has recently been found that a faster response can be obtained by using a smectic liquid crystal cell.

It has become clear that some optically active smectic liquid crystals exhibit ferroelectricity, and there are great expectations for their use. Liquid crystals exhibiting ferroelectric properties, ferroelectric liquid crystals, were developed in 1975 as R, T3.
゜Meyer et al. synthesized 4-(4-n
-Decyloxybenzylideneamino)cinnamic acid-2-methylbutyl ester (hereinafter abbreviated as DOBAMBC) is a typical example of the compound, and its chiral smectic C phase (hereinafter abbreviated as SmC* phase). It is characterized by exhibiting ferroelectricity (J,
Physique, 36. L-69 (1975)').

Recently, N. A. C1ark et al. (Appl.

Phys, Lctt, 36. 89 (19
80)), the DOBAMBC IFJ cell has high-speed response on the μSec order and memory performance.
With this discovery, ferroelectric liquid crystals have been used not only for displays such as LCD televisions, but also for optoelectronic-related devices such as optical printer heads, optical Fourier transform elements, and light valves, by taking advantage of their high-speed response. It is attracting attention as a material that can be used for raw materials.

Problems to be Solved by the Invention Liquid crystals are more or less physically and chemically decomposed by light, heat, water, oxygen, etc. However, in the case of nematic liquid crystals that do not normally contain dyes, it is possible to avoid the use of compounds that are particularly susceptible to physical and chemical decomposition, such as Schiff bases, and to use an appropriate encapsulant. No decomposition occurs.

However, in the case of the ferroelectric liquid crystal mentioned above, light.

The biggest cause of loss of device reliability is the loss of memory properties due to trace amounts of ionic impurities and highly polar impurities generated by physical and chemical decomposition caused by heat, water, oxygen, etc. It has become one. Therefore, an object of the present invention is to suppress the decomposition of ferroelectric liquid crystal in a ferroelectric liquid crystal element.

Means for Solving the Problems The present inventors have searched for various methods to solve the above-mentioned problems and have arrived at the present invention.

That is, the present invention has the following features:1. 2. Ferroelectric liquid crystal composition characterized in that an antioxidant is added; 2. Alignment film for a ferroelectric liquid crystal element characterized in that an antioxidant is coated on the surface of the alignment film for liquid crystal 3. 4. An alignment film for a ferroelectric liquid crystal device, characterized in that a polymer containing a group having antioxidation ability or radical scavenging ability, such as hindered phenol or hindered amine, is used as a structural unit. A sealant for ferroelectric liquid crystal elements characterized by using a polymer added with an antioxidant and an oxygen scavenger 5. Encapsulant for ferroelectric liquid crystal devices characterized by using a polymer containing a group having antioxidation ability or radical scavenging ability, such as hindered phenol or hindered amine, as one component 6゜1, 2. 3. 4. 5. The present invention relates to a strong M'l liquid crystal element characterized by containing as a constituent unit.

(In U, L, 1. Considering the balance between the temperature characteristics of liquid crystal and the ability to prevent decomposition, the preferable content of antioxidant is 0.001 to 10% by weight. The present invention is particularly effective when the compound contains a heterocyclic compound that is considered to be more susceptible to decomposition by water, oxygen, etc., a compound having an active hydrogen attached to a carbon adjacent to an aromatic ring or a carbonyl group, and a halogen compound. In addition, considering the balance between the alignment ability of the alignment film and the decomposition prevention ability in step 2, the preferable content of the antioxidant is 10:1 to 10,000 to the alignment agent by weight.
: 't between. In this case, the type of alignment film may be an oblique vapor deposition film of gold Yt oxide, a polymer film, or a Langmuir-Blodgett film. In addition, as a method for applying the antioxidant, for example, it can be dissolved in a solvent and coated with a spin cord.
Examples include printing, roll coating or dipping, and vapor deposition.

The working principle of the present invention is as follows.

First, radicals (11 free radicals) are generated in a ferroelectric liquid crystal by the action of light, heat, oxygen, etc.

Since these radicals attack and decompose other ferroelectric liquid crystal molecules, decomposition of the ferroelectric liquid crystal progresses in a chain reaction. Also.

When the radical reacts with dissolved oxygen in the ferroelectric liquid crystal, it becomes a peroxide, which also decomposes other ferroelectric liquid crystal molecules in a chain reaction. Therefore, the initially generated radicals are returned to the original ferroelectric liquid crystal using a compound (phenolic or amine antioxidant) or group that has radical scavenging ability, or the peroxide is converted to a peroxide decomposer (peroxide decomposer). If sulfur-based or phosphorus-based antioxidants are captured, further decomposition of the ferroelectric liquid crystal can be prevented. For this purpose, in the ferroelectric liquid crystal, in the alignment film, and in the sealing 1.
The principle of the present invention is that a compound or group having antioxidant 11-ability (radical scavenging ability or peroxide decomposition ability) may be present in the arsenic agent. In particular, if an oxygen scavenger is added to the sealing material, liquid crystal and
It is possible to prevent more than a trace amount of oxygen remaining in the alignment film from entering from outside the liquid crystal element.

Antioxidant 1L agents suitable for use in the present invention are, for example, compounds commercially available under the following trade names.

1. Phenolic antioxidant Sumilizer I3H'r (Sumitomo Chemical), Irganox 1076 (Ciba Geigy), Antige W4. OO(
Kawaguchi Chemical), Sumilizer BBM (Sumitomo Chemical), Mark AO30 (Adeka Argus), Irganox 1010
(Ciba Geigy), Irganox 1330 (
Ciba Geigy), Gutudrite 3114 (Gutudrich), Gutudrite 3125 (Gutudrich) 2, Sulfur-based antioxidant Antiox (NOF), Antiox M (NOF), Antiox S (NOF), Eastman Inhibitor TDP2000 (Yeast Mankodak), Mark A○-4128 (Adeka Argus), Mark AO-23 (Adeka Argus) 3, Phosphorous antioxidant mark 1178 (Adeka Argus), Mark 21.1
2 (Adeka Argus), Mark 1500 (Adeka Argus), Mark 260 (Adeka Argus), Mark PEI
'-8 (Adeka Argus), Sand Stub T')-Er
'Q (Sandoz), HCA (Tangen) 4, hindered amine antioxidant Sanol LS744 (Sankyo), Sanol LS770 (
Sankyo), Mark T, A62 (Adeka Argus), Sanol LS765 (Sankyo), Mark LA57 (Adeka Argus), Mark A2B (Adeka Argus), Mark LA67 (Adeka Argus), Mark LA63 (Adeka Argus), Tinuvin 144 ( Ciba Geigy), Thiasolve UV3346 (ACC), Spinupex A-
36 (Mante Dayson), Tinuvin 622LD (Ciba Geigy) Compounds suitable for use as the ferroelectric liquid crystal of the present invention include, for example, the following 1.2°3, 4. This is a compound as shown in

1. A ferroelectric liquid crystal developed by the applicants in the past.
JP-A-60-218358, JP-A-82. -46, JP 62-30740, JP 62-53943, JP 62-111950, JP 62-228068, JP 63-57553, JP 63-99032, JP 1-104031 Compounds disclosed in et al.

2. A group of compounds having a smectic C phase, such as the following.

Alkoxybiphenylcarboxylic acid alkyl ester, alkylcarbonyloxybiphenylcarboxylic acid alkyl ester, alkoxybenzoic acid alkoxyphenyl ester, alkoxybenzoic acid alkyloxycarbonylphenyl ester, alkoxybenzoic acid alkoxyalkoxyphenyl ester, alkoxybenzoic acid alkoxybiphenyl ester, alkoxybiphenyl carbon Acid alkoxyphenyl ester, alkylbenzoic acid alkoxybiphenyl ester, alkylbiphenylcarboxylic acid alkoxyphenyl ester, alkoxybenzoic acid alkylbiphenyl ester, alkoxybiphenylcarboxylic acid alkylphenyl ester, alkylcarbonyloxybenzoic acid alkoxybiphenyl ester, alkylcarbonyloxybiphenylcarboxylic acid Alkoxyphenyl ester, alkoxybenzoic acid alkylcarbonyloxybiphenyl ester, alkoxybiphenylcarboxylic acid alkylcarbonyloxyphenyl ester,
5-alkyl-2-(4'-alkoxyphenyl)pyrimidine, 5-alkoxy-2-(4'-alkoxyphenyl)pyrimidine, 5-alkyl-2-(4'-alkylcarbonyloxyphenyl)pyrimidine, 5-alkoxy -2-(4'-alkylcarbonyloxyphenyl)pyrimidine, 5-alkyl-2-(4'-alkyloxycarbonylphenyl)pyrimidine, 5-alkoxy-2-(4'-alkyloxycarbonylphenyl)pyrimidine, 5- Alkyl-2-(4'-alkoxyphenyl)pyrazine, 5-alkoxy-2-(4
' -alkoxyphenyl)pyrazine, 5-alkyl-
2-(4'-alkylcarbonyloxyphenyl)pyrazine, 5-alkoxy-2-(4'-alkylcarbonyloxyphenyl)pyrazine, 5-alkyl-2-(4
'-alkyloxycarbonylphenyl) pyrazine,
5-alkoxy-2-(4'-alkyloxycarbonylphenyl)pyrazine, 3-(4'-alkylphenyl)-6-alkoxypyridazine, 3-(4'-alkoxyphenyl)-6-alkoxypyridazine, 3-(
4'-alkoxyphenyl)-6-alkylpyridazine, 5-(4'-alkylphenyl)-2-(4''-alkoxyphenyl)pyrimidine, 5-(4''-alkoxyphenyl)-2-(4''-alkoxy phenyl)pyrimidine, 5-(4'-alkylphenyl)-2-(
4”-alkylcarbonyloxyphenyl)pyrimidine, 5(4′-alkoxyphenyl)-2-(4”-alkylcarbonyloxyphenyl)pyrimidine, 5-(
4'-alkylphenyl)-2-(4''-alkyloxycarbonylphenyl)pyrimidine, 5-(4'-
alkoxyphenyl)-2-(4''-alkoxycarbonylphenyl)pyrimidine, 5-(4'-alkoxyphenyl)-2-(4''-alkoxyphenylcarbonyloxy)pyrimidine, 5-(4'-alkylphenyl)- 2(4”-alkoxyphenylcarbonyloxy)pyrimidine, 5-(4′-alkoxyphenyl)-
2-(4”-alkylphenylcarbonyloxy)pyrimidine, 5-(4′-alkylphenyl)-2-(4
”-alkylphenylcarbonyloxy)pyrimidine,
5-(4′-alkylphenyl)-2-(4”-alkoxyphenyl)-1,2,4-)riazine, 5-(4
'-alkoxyphenyl)-2-(4''-alkoxyphenyl)-1゜2.4-) riazine, 5- (4'
-alkylphenyl)-2-(4”-alkylcarbonyloxyphenyl)-1,2,4-triazine, 5-(
4′-alkoxyphenyl)-2(4”-alkylcarbonyloxyphenyl)-1,2,4-)riazine, 5
- (4'-alkylphenyl)-2-(4''-alkyloxycarbonylphenyl)-1,2,4-triazine, 5- (4'-alkoxyphenyl)-2-(4
”-alkyloxycarbonylphenyl)-1,2,4
-) Reazine etc. 3.2. It has a smectic C phase in which one or more hydrogen atoms contained in the alkyl moiety or skeleton of the compound group listed in is substituted with a halogen, cyano group, nitro group, trifluoromethyl group, alkoxy group, alkyl group, etc. Compound.

4.2. Or 3. One or more hydrogen atoms in the alkyl moiety of the alkyl group, alkoxy group, alkylcarbonyloxy group, alkyloxycarbonyl group of the compound groups listed in A group of compounds in which an asymmetric carbon is introduced by substitution with a smectic compound, and which are made into ferroelectric liquid crystals exhibiting a chiral smectic C phase either alone or by mixing with a smectic compound.

In addition, the ZLI series (
Merck), CS series (Chisso), TKF series (
It can also be used for Teikoku Kagaku Sangyo) and DOF series (Dainippon Ink).

Examples of alignment agents suitable for use in the present invention include the following.

Polyimide, polyamide, polyolefin.

Thin films and their precursors such as polyvinyl alcohol, Teflon, polyether, polyacrylic acid, polyvinylidene fluoride, organopolysilane, silicon oxide, yttrium oxide, etc.

Effect of the Invention By using the ferroelectric liquid crystal composition, the alignment film for ferroelectric liquid crystal elements, the sealant for ferroelectric liquid crystal elements, and the ferroelectric liquid crystal display element of the present invention, the decomposition and alignment of liquid crystal materials can be improved. Since film deterioration can be suppressed, the environmental stability of liquid crystal elements can be improved.
In particular, thermal stability can be improved.

EXAMPLES The ferroelectric liquid crystal composition, the alignment film for ferroelectric liquid crystal elements, the sealant for ferroelectric liquid crystal elements, and the ferroelectric liquid crystal display element of the present invention will be explained in more detail by examples below. The present invention is not limited to these Examples.

Example 1 A ferroelectric liquid crystal composition (A) having the following composition was prepared.

5-octyl-2-(4'-octyloxyphenyl)pyrimidine 25wt% 5-nonyl-2-(4'-nonyloxyphenyl)pyrimidine 25wt% 5-hebutyl-2-(4'-decyloxyphenyl)
Pyrimidine 25wt% (S)-4-octyloxybenzoic acid-2-methylbutyloxyphenyl ester 25wt% 0.2wt% Irganox 1076 for (A)
Ferroelectric liquid crystal compound (I) added with (Ciba Geigy)
heating test (125'C.

(in air for 1 week).

No coloring of the compound (i) was observed. Thus, according to the present invention, it has been revealed that coloring of ferroelectric liquid crystals due to heating can be prevented by adding an antioxidant.

Further, the compound (I) was injected into a liquid crystal cell with a cell thickness of 2 microns constructed using I'TO glass coated with polyimide as an alignment film, and observed under a polarizing microscope while applying a 10 V square wave. Good contrast and high-speed response were observed, and it was confirmed that within the range of the amount of addition of the present invention, the addition of the antioxidant can be used as a material without having a significant effect on the performance as a ferroelectric liquid crystal.

Ratio Example 1 Heating test of compound (A) (125°C, in air, 1 week)
was carried out. Compound (A) was colored brown.

Example 2 A ferroelectric liquid crystal compound (c) having the following composition was prepared.

5-Alkyl-2-(4'-alkoxyphenyl)pyrimidine 50wt% 4-alkyloxybenzoic acid-2-alkyloxyphenyl ester 20wt% (S)-4-octyloxybenzoic acid-2-methylbutyloxyphenyl ester 20wt % (2S, 3S) -4”-(2-chloro-3-methylbutylcarbonyloxy)-42-octyloxybiphenyl 10wt% Ferroelectric with 2wt% Sumilizer BIIT (Sumitomo Chemical) added to (U) Heating test of liquid crystal compound (e)
(125°C, in air, for 1 week).

(E) No coloring was observed. Thus, according to the present invention, it has been revealed that coloring of a ferroelectric liquid crystal containing a heterocyclic compound or a halogen compound due to heating can be prevented by adding an antioxidant.

In addition, the compound (e) after the heating test was injected into a liquid crystal cell with a cell thickness of 2 microns constructed using ITO glass on which silicon oxide was orthogonally deposited as an alignment film, and a rectangular wave of IOV was applied to polarize the cell. Observed under a microscope. Good orientation, contrast and high-speed response can be observed, and within the range of the amount added in the present invention,
It was confirmed that the addition of an antioxidant can be used as an additive without adversely affecting the performance as a ferroelectric liquid crystal.

Comparative Example 2 The formulation (U) was similarly subjected to a heating test (125°C, in air,
1 week), it turned brown.

In addition, when the mixture (c) after the heating test was injected as an alignment film into a liquid crystal cell with a cell thickness of 2 microns constructed using IT○ glass on which silicon oxide was orthographically deposited, poor alignment occurred in some parts of the cell. It has become clear that thermal deterioration affects the performance of liquid crystals.

Example 3 Is it a substitute for Sumilizer B I-I T in Example 2? , :1. A heating test of the formulation was conducted in exactly the same manner except that MARK-AO80 (7 Deca Argus) was used.

Furthermore, it was injected into a liquid crystal cell and its electrical properties were measured. gA11 has good orientation, contrast and fast response! ! I can,
It was confirmed in a heating test that a ferroelectric liquid crystal element with good environmental resistance can be obtained by using not only BHT but also a hindered phenol-based antioxidant.

Example 4 Replacement of Sumilizer B HT in Example 2! ,
: MARK-AO80 (7' Deca Argus) 0.25
wt% and sulfur-based antioxidant MARK-AO412S (
A heating test of the formulation was conducted in the same manner except that 7 Dekaaga, X)wo 0°75'wt% was used. Furthermore, it was injected into a liquid crystal cell and its electrical properties were measured. Good alignment, contrast, and high-speed response can be observed, and even in a system that uses a phenolic antioxidant and a sulfur-based antioxidant, a ferroelectric liquid crystal element with good environmental resistance can be obtained in a heating test. It could be confirmed.

Example 5 A heating test of the compound was carried out in the same manner as in Example 2 except that the phosphorous antioxidant MARKAO2112 was used instead of Sumilizer BHT. Furthermore, it was injected into a liquid crystal cell and its electrical properties were measured. Good alignment, contrast, and high-speed response were observed, and it was confirmed that ferroelectric liquid crystal elements with good environmental resistance can be obtained in heating tests even when using not only hindered phenol-based antioxidants but also phosphorus-based antioxidants. Ta.

Example 6 ITO glass coated with polyimide as an alignment film,
After dipping in an ethanol solution of Sumilizer B HT, it was dried, and a thin layer of antioxidant was adsorbed onto the surface. After rubbing, the compound (c) was injected into a liquid crystal cell with a cell thickness of 2 microns constructed using this glass and sealed. Heating test (1
25°C, in air, for 1 week) Apply a 10V square wave and apply it under a polarizing microscope! I guessed it.

Good alignment, contrast, and high-speed response were observed, and it was confirmed that a ferroelectric liquid crystal element with good environmental resistance could be obtained by coating the surface of the alignment film with an antioxidant.

Example 7 A liquid crystal cell was prepared in the same manner as in Example 3, except that an obliquely vapor-deposited film of silicon oxide was used instead of polyimide as the alignment film, and the mixture (c) was injected and sealed. Heating test (1
25° C., in air for 1 week) A 10 V rectangular wave was applied and observed under a polarized R microscope. Good alignment, contrast, and high-speed response were observed, and it was confirmed that a ferroelectric liquid crystal element with good environmental resistance could be obtained by coating the surface of the alignment film with an antioxidant.

Example 8 A sample containing 0.05 wt % of Irganox 1010 (Ciba Geigy) added to a polyimide solution was spin-coded onto ITO glass to prepare an alignment film containing an antioxidant 1E material. After rubbing, the compound (c) was injected into a liquid crystal cell with a cell thickness of 2 microns constructed using this glass and sealed. After heating test (125°C, in air, 1 week),
Polarize by applying IOV square wave! lJ [Observed under machine gun. It was confirmed that a ferroelectric liquid crystal element with good alignment, contrast, and high-speed response could be obtained, and by incorporating an antioxidant into the polymer alignment film, a ferroelectric liquid crystal element with good environmental resistance could be obtained.

Effects of the Invention By using an antioxidant as in the present invention, a ferroelectric liquid crystal composition, a sealant for a ferroelectric liquid crystal element, and a sealant for a ferroelectric liquid crystal element can be used in a ferroelectric liquid crystal display element. By using it as a constituent material, a useful ferroelectric liquid crystal display element with good anti-152 boundary properties, particularly good thermal stability, a ferroelectric liquid crystal composition that is a constituent material thereof, and an alignment film for ferroelectric liquid crystal element 1 A sealant for dielectric liquid crystal elements can be provided.

Claims (7)

[Claims] (1) Ferroelectric liquid crystal composition characterized by adding an antioxidant (2) A ferroelectric liquid crystal composition characterized in that the content of the antioxidant according to claim (1) is from 0.001 to 10% by weight. (3) The ferroelectric liquid crystal composition according to claim (1), which contains a compound, a heterocyclic compound, or a halogen compound having an active hydrogen bonded to carbon adjacent to an aromatic ring or a carbonyl group. (4) A ferroelectric liquid crystal element characterized in that an antioxidant is coated on the surface of a liquid crystal alignment film formed by a polymer film, an oblique evaporation film of a metal oxide, or a Langmuir-Blodgett film. alignment film for (5) At least a, a polymer added with an antioxidant, b, and a polymer containing a group having antioxidant ability or radical scavenging ability, such as hindered phenol or hindered amine, as a structural unit. Alignment film for ferroelectric liquid crystal elements (6) At least a, a polymer added with an antioxidant or an oxygen scavenger b, and a polymer containing a group having antioxidant or radical scavenging ability such as hindered phenol or hindered amine as a structural unit. Encapsulant for ferroelectric liquid crystal elements characterized by (7) The ferroelectric liquid crystal composition as described in claim (1), (2), and (3), the alignment film for ferroelectric liquid crystal element as described in claim (4), and (5); A ferroelectric liquid crystal device comprising at least one of the encapsulants for ferroelectric liquid crystal devices described in item 6) as a constituent element.