JPH083557A - Ferroelectric liquid crystal composition and display element using the same - Google Patents

Abstract

PURPOSE:To obtain a ferroelectric liquid crystal composition which is composed of a mixture of a specific liquid crystal compound of high molecular weight with a ferroelectric liquid crystal compound of low molecular weight, thus is useful as a display and an electronic shutter or the like because of its quick response, memory characteristics, shock resistance or the like. CONSTITUTION:This composition comprises (A) a liquid crystal compound of high molecular weight having recurring units of formula I [A and B are each 1,4-phenylene, 2,5-pyridine or either A or B is a single bond; X1-X3 are H, a lower alkyl; R1 is a (halogen-substituted) 1 20C alkyl, a (halogen-substituted) 2-20C alkoxyalkyl; X is -CH2CH2-; q is an integer of 1-15; r is an integer of 0-6; s is 0, 1; * is an asymmetric carbon atom] and 1,000-50,000 number-average molecular weight and (B) a ferroelectric liquid crystal compound, preferably of formula II (R2 is a 3-20C alkyl; R3 is a (halogen-substituted) 1-20C alkyl; U is -O-, -CH2CH2-; W is -COO-; Z is -O-, -COO-; K is 0, 1].

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a ferroelectric liquid crystal composition. More specifically, the present invention is useful as various electro-optical devices such as display elements, electronic shutters, optical modulators, and optical waveguides, and can be used for large-screen and bent-screen display elements that are excellent in shock resistance. The present invention relates to a liquid crystal composition containing a polymer liquid crystal material exhibiting a ferroelectric phase and having a high-speed response, and a display device using the same.

[0002]

2. Description of the Related Art Conventionally, display devices using low-molecular liquid crystals have been widely used in calculators, watches, displays and the like. In these fields of use, a panel in which a low-molecular liquid crystal is sandwiched between two glass substrates whose spacing is controlled to the order of several microns is used. However, it is very difficult to control the spacing on the order of a few microns over a large area,
In the low-molecular liquid crystal system, stable supply of a large-screen display has not been realized yet. Further, since the low molecular weight liquid crystal has no self-supporting property, a glass substrate has to be used, a curved screen cannot be realized, and there is a problem in weight reduction.

As one means for solving these problems, studies have been made on polymerizing liquid crystals to impart self-supporting property. (J. Polym. Sci., Polym.
Lett., 1975, Ed. 13, 243, Poly
Bull., 1982, 6, 309). However, these polymer liquid crystals cannot be used for displaying moving images because of the slow response time to changes in external factors such as electric field.

In order to overcome this, various studies have been made on ferroelectric polymer liquid crystals having a ferroelectric liquid crystal structure having a fast response in a side chain. These ferroelectric polymer liquid crystals can be aligned by applying shearing force such as bending, but they are difficult to align depending on the material, and the memory property which is one of the characteristics of ferroelectric liquid crystals cannot be obtained. There were cases.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the drawbacks of the conventional low-molecular liquid crystals and polymer liquid crystals, has sufficient memory properties, is excellent in impact resistance, and is lightweight and large-sized. It is an object of the present invention to provide a ferroelectric liquid crystal composition that can be used as a display element for screens and curved screens, and a display element using the same.

[0006]

[Means for Solving the Problem] The inventors of the present invention have conducted extensive studies to achieve the above-mentioned object, and as a result, have found that a specific liquid crystal polymer compound (hereinafter, sometimes referred to as polymer liquid crystal) It was found that a liquid crystal composition having a high memory property can be obtained by mixing a dielectric liquid crystal compound and using the liquid crystal polymer compound, and completed the present invention.

The present invention will be described below. [1] Ferroelectric liquid crystal containing a liquid crystal polymer compound having a number average molecular weight of 1,000 to 50,000 containing a repeating unit of the general formula (1) as a main component, and a ferroelectric liquid crystal compound excluding the liquid crystal polymer compound Composition.

[0008]

Embedded image

(In the formula, A and B are 1, 4-
Phenylene, 2,5-pyridine, 2,5-pyrimidine,
2,5-pyrazine, 3,6-pyridazine, 4,4'-biphenyl, 5- (2-phenylpyrimidine), 2- (5
-Phenylpyrimidine), 2- (5-phenylpyridine), 2,6-naphthalene, 2,6-quinoline, 2,6
-Quinoxaline represents a group selected from 2,6-quinazoline, or either A or B represents a single bond (wherein the phenyl ring may be substituted with a fluorine atom). X ₁ , X ₂ and X ₃ each represent a hydrogen atom or a lower alkyl group, and R ₁ represents a saturated or unsaturated alkyl group having 1 to 20 carbon atoms which may be substituted with a halogen atom, or a halogen atom. in alkoxyalkyl group a saturated or unsaturated optionally having 2 to 20 carbon atoms which may be substituted, X is _{-CH 2 CH 2 -, - CH} =
CH-, -C≡C- or a single bond, and q is 1 to 15
, R is an integer of 0 to 6, and s is 0 or 1. Also, * indicates that it is an asymmetric carbon atom. )

[2] The ferroelectric liquid crystal composition according to item [1], wherein the ferroelectric liquid crystal compound is represented by the following general formula (2).

[0011]

[Chemical 4]

(In the formula, A and B are the same as A and B described in the above item [1]. R ₂ represents an alkyl group having 3 to 20 carbon atoms, and R ₃ is substituted with a halogen atom. Optionally saturated or unsaturated alkyl group having 1 to 20 carbon atoms or 2 carbon atoms optionally substituted by a halogen atom
~ 20 saturated or unsaturated alkoxyalkyl groups. U is _{-O -, - CH 2 CH 2} -, - CH = CH
-, -C≡C- or a single bond, W is -COO-,
Represents -OCO- or a single bond (provided that U is -CH =
In the case of CH- or -C≡C-, W is a single bond. ) And Z represent -O-, -COO- or -OCO-, r represents an integer of 0 to 6, and s and k each independently represent 0 or 1. The * mark indicates an asymmetric carbon atom. )

[3] A display device using the ferroelectric liquid crystal composition according to the above item [1] or [2].

The present invention will be described in detail below. The liquid crystal polymer compound used in the present invention preferably exhibits a ferroelectric phase in a wide temperature range including normal temperature. The liquid crystal polymer compound represented by the general formula (1) contained in the ferroelectric liquid crystal composition of the present invention is represented by the following general formula (3).

[0015]

Embedded image

(Here, the definitions of X ₁ , X ₂ and X ₃ are the same as those in the above general formula (1).) X ₁ , X ₂ and X ₃ are specifically, independently of each other hydrogen. An atom, a methyl group, an ethyl group, a propyl group and the like can be mentioned. Next, the side chain portion D represented by the general formula (3)
Is illustrated. In the example of D, the definition of q is the same as the definition in the general formula (1). R ₄ is the general formula (1)
In

[0017]

[Chemical 6] And the definitions of s and R ₁ are the same as in the general formula (1).

Specific examples of R ₁ include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, Propenyl, 2-butenyl, 3-butenyl, 3-hexenyl, 2-butynyl, 3-hexynyl, cyclopropyl, 2,2-dimethylcyclopropyl, cyclopentyl, cyclohexyl, octadecyl, nonadecyl, eicosyl, methoxymethyl, methoxyethyl, methoxy. Propyl, methoxybutyl, methoxypentyl, methoxyhexyl, methoxyheptyl, methoxyoctyl, methoxynonyl, methoxydecyl, ethoxymethyl, ethoxyethyl,

Ethoxypropyl, ethoxybutyl, ethoxypentyl, ethoxyhexyl, ethoxyheptyl,
Ethoxyoctyl, ethoxynonyl, ethoxydecyl,
Propoxymethyl, propoxyethyl, propoxypropyl, propoxybutyl, propoxypentyl, propoxyhexyl, propoxyheptyl, propoxyoctyl, propoxynonyl, propoxydecyl, butoxy, butoxymethyl, butoxyethyl, butoxypropyl, butoxybutyl, butoxypentyl, butoxy. Hexyl, butoxyheptyl, butoxyoctyl, butoxynonyl, butoxydecyl, pentyloxymethyl, pentyloxyethyl, pentyloxybutyl,

Pentyloxypentyl, pentyloxyhexyl, pentyloxyheptyl, pentyloxyoctyl, pentyloxynonyl, pentyloxydecyl, hexyloxymethyl, hexyloxyethyl, hexyloxypropyl, hexyloxybutyl, hexyloxypentyl, hexyloxyhexyl Hexyloxyheptyl, hexyloxyoctyl, hexyloxynonyl, hexyloxydecyl, heptyloxymethyl, heptyloxyethyl, heptyloxypropyl, heptyloxybutyl, heptyloxypentyl,
Heptyloxyhexyl, heptyloxyheptyl, heptyloxyoctyl, heptyloxynonyl, heptyloxydecyl, octyloxymethyl, octyloxyethyl, octyloxypropyl, octyloxybutyl, octyloxypentyl, octyloxyhexyl, octyloxyheptyl, octyloxy Octyl, octyloxynonyl, octyloxydecyl, nonyloxymethyl, nonyloxyethyl, nonyloxypropyl, nonyloxybutyl, nonyloxypentyl, nonyloxyhexyl, nonyloxyheptyl, nonyloxyoctyl, nonyloxynonyl, nonyloxydecyl, Decyloxymethyl, decyloxyethyl,

Decyloxypropyl, decyloxybutyl, decyloxypentyl, decyloxyhexyl, decyloxypentyl, decyloxyoctyl, decyloxynonyl, decyloxydecyl, 1-methylethyl,
1-methylpropyl, 1-methylbutyl, 1-methylpentyl, 1-methylhexyl, 1-methylheptyl, 1
-Methyloctyl, 1-methylnonyl, 1-methyldecyl, 2-methylpropyl, 2-methylbutyl, 2-methylpentyl, 2-methylhexyl, 2-methylheptyl, 2-methyloctyl, 2,3-dimethylbutyl,
2,3,3-trimethylbutyl, 3-methylpentyl,
2,3-dimethylpentyl, 2,4-dimethylpentyl, 2,3,3,4-tetramethylpentyl, 3-methylhexyl, 2,5-dimethylhexyl,

2-trihalomethylpropyl, 2-trihalomethylbutyl, 2-trihalomethylpentyl, 2-trihalomethylhexyl, 2-trihalomethylheptyl,
2-haloethyl, 2-halopropyl, 3-halopropyl, 3-halo-2-methylpropyl, 2,3-dihalopropyl, 2-halobutyl, 3-halobutyl, 4-halobutyl, 2,3-dihalobutyl, 2,4 -Dihalobutyl,
3,4-dihalobutyl, 2-halo-3-methylbutyl,
2-halo-3,3-dimethylbutyl, 2-halopentyl, 3-halopentyl, 4-halopentyl, 5-halopentyl, 2,4-dihalopentyl, 2,5-dihalopentyl, 2-halo-3-methylpentyl, 2- Halo-4-
Methylpentyl, 2-halo-3-monohalomethyl-4-
Methylpentyl, 2-halohexyl, 3-halohexyl, 4-halohexyl, 5-halohexyl, 6-halohexyl, 2-haloheptyl, 2-halooctyl, (However, in the above exemplification, halo represents a fluorine, chlorine or bromine atom. .) And the like.

Further, in the case of s = 1, as specific examples of R ₁ , in addition to the above-mentioned examples, halomethyl, 1-haloethyl, 1-halopropyl, 1-halobutyl, 1-halopentyl, 1-halohexyl, 1-haloheptyl, 1-
Halooctyl and the like can be mentioned.

These alkyl groups or alkoxyl groups may be linear, branched or cyclic, and if branched or cyclic, they may be optically active groups.

[0025]

[Chemical 7]

[0026]

Embedded image

[0027]

[Chemical 9]

[0028]

[Chemical 10]

[0029]

[Chemical 11]

[0030]

[Chemical 12]

[0031]

[Chemical 13]

[0032]

Embedded image

[0033]

[Chemical 15]

[0034]

Embedded image

[0035]

[Chemical 17]

[0036]

Embedded image

[0037]

[Chemical 19]

[0038]

Embedded image

Next, the ferroelectric liquid crystal compound used in the present invention will be described. The ferroelectric liquid crystal compound used in the present invention excludes the above liquid crystal polymer compounds and is not particularly limited. Examples thereof include low-molecular compounds having a ferroelectric Sc ^* phase such as azomethine compounds, Schiff base compounds, azo and azoxy compounds, biphenyl compounds, aromatic ester compounds, and phenylpyrimidine compounds. Moreover, you may use these compounds in mixture of 2 or more types.

Further, the ferroelectric liquid crystal compound used in the present invention may be used as a composition by adding another physical property improving agent. Specifically, for example, a liquid crystal composition showing a ferroelectric Sc ^* phase obtained by adding an improving agent to the above-mentioned ferroelectric liquid crystal compound, or a smectic liquid crystal compound as a base liquid crystal and adding a chiral agent to the liquid crystal composition A composition showing an Sc ^* phase, for example, an azomethine-based ferroelectric liquid crystal compound exemplified in JP-A-62-260841 and a composition containing them, are exemplified in JP-A-3-12487. Phenylpyrimidine-based ferroelectric liquid crystal compounds and compositions containing them,

Biphenyl-based ferroelectric liquid crystal compounds and compositions containing them exemplified in JP-A-3-83949, JP-A-59-98051 and JP-A-60-
Schiff base ferroelectric liquid crystal compounds exemplified in 199865 and compositions containing the same, JP-A-61-61
-Azoxy-based ferroelectric liquid crystal compounds and compositions containing them, which are exemplified in JP-A-183256,
Aromatic ester-based ferroelectric liquid crystal compounds exemplified in 167251 and compositions containing them, phenylpyrimidine compounds and phenylpyridine compounds showing smectic liquid crystals exemplified in JP-A-3-207790 A ferroelectric liquid crystal composition comprising a biphenyl compound or an aromatic ester compound as a matrix liquid crystal and a chiral compound added thereto.
Examples include phenylpyrimidine-based ferroelectric liquid crystal compounds and compositions containing them, which are exemplified in JP-A-178369.

As the ferroelectric liquid crystal compound, a ferroelectric liquid crystal compound represented by the following general formula (2) can be used.

[Chemical 21] (In the formula, A, B, R ₂ , R ₃ , U, W, Z, r, s, and k represent the same as described above. * Indicates an asymmetric carbon atom.)

Specific examples of the ferroelectric liquid crystal compound used in the present invention are shown below. In the exemplified compounds below, R ₂ represents an alkyl group having 3 to 20 carbon atoms, and k, U, Z, and n are the same as defined in the general formula (2). R ₅ represents an alkyl group having 2 to 20 carbon atoms or an alkoxyalkyl group having 3 to 20 carbon atoms. Examples of R ₅ include a methyl group, an ethyl group, an acetyl group or a propanoyl group.

[0044]

[Chemical formula 22]

[0045]

[Chemical formula 23]

[0046]

[Chemical formula 24]

[0047]

[Chemical 25]

In the ferroelectric liquid crystal composition of the present invention, the compounding ratio of the low molecular weight ferroelectric liquid crystal compound to the entire composition is preferably 5 to 90% by weight, more preferably 4%.
It is 0 to 80% by weight. When the compounding ratio of the low-molecular-weight ferroelectric liquid crystal compound is less than 5% by weight, the effect of improving the memory property is not sufficient, and when it exceeds 90% by weight, impact resistance may be adversely affected, which is not preferable.

The ferroelectric liquid crystal composition of the present invention can be easily aligned by a usual alignment method carried out in a liquid crystal polymer compound, for example, a method of applying a shearing force such as bending or shearing, and has a high memory property. It is possible to obtain a liquid crystal element having Furthermore, since it contains a low molecular weight compound, it is possible to easily align it even with an alignment film that has been subjected to a rubbing treatment, as compared with the case where only the high molecular weight compound is used. Further, since it contains a polymer compound, it has excellent impact resistance, and by sandwiching it with a plastic substrate or the like, the weight can be reduced, and it can be applied to a curved panel. Furthermore, since the composition of the present invention has the self-supporting property which is a characteristic of a polymer compound, it has the advantage that gravity obstacles are alleviated and the composition can be easily spread to a large panel.

The liquid crystal polymer compound represented by the general formula (1) used in the present invention is, for example, the following general formula (4).

[Chemical formula 26]

(In the formula, A and B are 1, 4-
Phenylene, 2,5-pyridine, 2,5-pyrimidine,
2,5-pyrazine, 3,6-pyridazine, 4,4'-biphenyl, 5- (2-phenylpyrimidine), 2- (5
-Phenylpyrimidine), 2- (5-phenylpyridine), 2,6-naphthalene, 2,6-quinoline, 2,6
-Quinoxaline, a group selected from 2,6-quinazoline, or either A or B represents a single bond. (Here, the phenyl ring may be substituted with a fluorine atom.) X ₁ , X ₂ and X ₃ each represent a hydrogen atom or a lower alkyl group, and R ₁ is a halogen atom. Represents a saturated or unsaturated alkyl group having 1 to 20 carbon atoms or a saturated or unsaturated alkoxyalkyl group having 2 to 20 carbon atoms which may be substituted with a halogen atom, and X represents —CH ₂ CH ₂ -, -CH = C
H-, -C≡C- or a single bond is represented, q is an integer of 1 to 15, r is an integer of 0 to 6, and s is 0 or 1. Also, * indicates that it is an asymmetric carbon atom. )

The acrylate monomer represented by the formula (1) was added to AIBN (2,2'-azobisisobutyronitrile) or 2,2'-azobis (4-methoxy-2,4-dimethylvaleonitrile) under an inert gas atmosphere. ), Using tetrahydrofuran, N, N-dimethylformamide or the like as a solvent,
It can be synthesized by reacting in the temperature range of 20 to 60 ° C. for 8 to 120 hours. Here, the liquid crystal polymer compound having an arbitrary molecular weight distribution is prepared by appropriately combining a reaction temperature, a reaction solvent, a polymerization initiator and the like, or fractionating by GPC column chromatography, and further combining them. be able to.

The ferroelectric liquid crystal composition of the present invention can be formed into a film by a known film forming method, for example, casting, T-die method, inflation method, calender method, stretching method or the like. The liquid crystal composition of the present invention in the form of a film is sandwiched between not only two ordinary glass substrates but also a large glass substrate, a curved glass substrate, a polyester film, etc., and a liquid crystal display, an electro-optical shutter, an electro-optical device. It can be used in various fields of optoelectronics such as diaphragms. Alternatively, the ferroelectric liquid crystal composition of the present invention dissolved in an appropriate solvent may be applied to the surface of a substrate such as a glass substrate, and the solvent may be evaporated to form a film directly in the state of close contact with the substrate.

The ferroelectric liquid crystal composition thus obtained exhibits a liquid crystal phase in a wide temperature range including room temperature and, at the same time, has a property as a polymer that it is easily molded, so There are many potential applications in fields such as information storage materials.

[0055]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Alignment of the liquid crystal polymer compound and the liquid crystal polymer composition was performed by enclosing the liquid crystal polymer compound and the liquid crystal polymer composition in a cell in which two glass substrates with ITO were coated with alignment films. The phase transition temperature and the glass transition temperature were measured by polarization microscope observation or DSC measurement. The memory property is measured by using the simple pulse method, and the difference in transmitted light amount between the bright state and the dark state when a voltage is applied by a pulse (± 10 V / μm) and the light and darkness in the memory state when no voltage is applied, which is induced by the difference. It was carried out by taking the ratio of the difference in the amount of transmitted light in each state, and expressed as a memory rate. In the following description, Sx represents an unidentified smectic phase, Sc ^* represents a chiral smectic C phase, and I represents an isotropic phase. The temperature in parentheses represents the transition temperature. Further, the transition temperature was determined by visual observation of the texture change at the time of temperature rise with a polarization microscope.

Example 1 A ferroelectric liquid crystal polymer compound (I) having the following structure and having a number average molecular weight (Mn) of 4000,

[Chemical 27]

And a ferroelectric liquid crystal compound (II) having the following structure:

[Chemical 28]

Were mixed in the isotropic phase. The phase sequence and memory ratio of the obtained ferroelectric liquid crystal composition were as follows. The phase transition behavior of the obtained polyacrylate (ferroelectric liquid crystal polymer compound (I)) was as follows. When A: (I) :( II) = 50% by weight: 50% by weight

[Chemical 29] Memory rate: 49% (25 ° C) B: (I): (II) = 20% by weight: 80% by weight

Embedded image Memory rate: 61% (25 ℃)

Comparative Example 1 The phase sequence and memory ratio of each of the liquid crystal polymer compound (I) and the ferroelectric liquid crystal compound (II) used in Example 1 were as follows. C: Ferroelectric polymer liquid crystal (I) alone

[Chemical 31] Memory rate: 0% (25 ° C) D: In the case of using the ferroelectric liquid crystal compound (II) alone

Embedded image Memory rate: 10% (25 ℃)

[0060]

The liquid crystal polymer compound used in the present invention exhibits a liquid crystal phase in a wide temperature range including normal temperature, and has typical properties as a polymer. Liquid crystal composition has shock resistance (shock resistance)
It is effective as a liquid crystal composition for display devices having excellent large screen and curved screen. It also has excellent memory performance. Specifically, a display element, an electro-optical shutter, an optical modulator,
It is useful for various electro-optical devices such as optical waveguides and has great industrial value.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C09K 19/44 9279-4H 19/46 9279-4H G02F 1/13 500 1/141 (72) Invention Person Takayuki Higashi 2-10-1, Tsukahara, Takatsuki City, Osaka Prefecture Sumitomo Chemical Co., Ltd. (72) Inventor Masayoshi Minai 2-10-1, Tsukahara, Takatsuki City, Osaka Prefecture Sumitomo Kagaku Kogyo Co., Ltd.

Claims (3)

[Claims] 1. A number average molecular weight of 1,000 to 50,000 having a repeating unit of the general formula (1) as a main component.
2. A ferroelectric liquid crystal composition containing the liquid crystal polymer compound of 1. and a ferroelectric liquid crystal compound other than the compound. Embedded image (In the formula, A and B are respectively 1,4-phenylene,
2,5-pyridine, 2,5-pyrimidine, 2,5-pyrazine, 3,6-pyridazine, 4,4'-biphenyl, 5
-(2-phenylpyrimidine), 2- (5-phenylpyrimidine), 2- (5-phenylpyridine), 2,6-
A group selected from naphthalene, 2,6-quinoline, 2,6-quinoxaline, 2,6-quinazoline, or either A or B represents a single bond (wherein the phenyl ring is substituted with a fluorine atom). It may have been.) X ₁ , X
₂ and X ₃ each represent a hydrogen atom or a lower alkyl group, and R ₁ represents a saturated or unsaturated alkyl group having 1 to 20 carbon atoms which may be substituted with a halogen atom, or a halogen atom. 2 to 2 carbon atoms
20 represents a saturated or unsaturated alkoxyalkyl group, X is —CH ₂ CH ₂ —, —CH═CH—, —C≡C
-Or a single bond, q is an integer of 1 to 15, r is 0 to
Represents an integer of 6, and s represents 0 or 1. Also, * indicates that it is an asymmetric carbon atom. ) 2. The ferroelectric liquid crystal composition according to claim 1, wherein the ferroelectric liquid crystal compound is represented by the following general formula (2). Embedded image (In the formula, A and B are the same as A and B in claim 1. R ₂ represents an alkyl group having 3 to 20 carbon atoms,
R ₃ has 1 to 7 carbon atoms which may be substituted with a halogen atom.
It represents a saturated or unsaturated alkyl group having 20 or a saturated or unsaturated alkoxyalkyl group having 2 to 20 carbon atoms which may be substituted with a halogen atom. U is -O
_{-, - CH 2 CH 2 -} , - CH = CH -, - C≡C- or a single bond, W is -COO -, - OCO- or a single bond and represents (where, U is -CH = CH- Or -C
In the case of ≡C-, W is a single bond. ), Z is -O-,
Represents -COO- or -OCO-, r represents an integer of 0 to 6, and s and k each independently represent 0 or 1. The * mark indicates an asymmetric carbon atom. ) 3. A display device using the ferroelectric liquid crystal composition according to claim 1.