JP2013006977A - Liquid crystal composition having negative dielectric anisotropy, and liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal composition having a negative dielectric anisotropy; and to provide a liquid crystal display device using the same.SOLUTION: The liquid crystal composition having a negative dielectric anisotropy contains at least one compound represented by formula (I) and at least one compound represented by formula (II) (wherein Rand Rare each independently 1-8C alkyl, alkoxy, 2-8C alkenyl or alkenyloxy; ais 0 or 1; Aand Aare each independently a specific divalent 6-membered ring; and Rand Rare each independently 1-8C alkyl or alkoxy).

Description

  The present invention relates to a liquid crystal composition having a negative dielectric anisotropy (Δε) useful as an electro-optical liquid crystal display material, and a liquid crystal display element using the liquid crystal composition.

  A vertical alignment type VA-LCD using a liquid crystal composition having negative dielectric anisotropy (negative Δε) is capable of expressing jet black and has excellent display quality and a high contrast liquid crystal display device. As a result, it is widely used in the market centering on LCD TVs. Recently, in addition to an active matrix drive system represented by a liquid crystal television or the like, a VA-LCD is also increasingly used in a passive matrix drive system used as a display for in-vehicle or home appliance applications. In liquid crystal television applications, the gap between the glass substrates tends to be narrowed in order to achieve smooth moving image display performance, and the birefringence (Δn) of the liquid crystal material tends to increase. On the other hand, in an in-vehicle display, a liquid crystal composition having a negative Δε is required to have a large Δn that is unprecedented in order to obtain a good contrast even in a high time-division drive with a large display capacity, and the voltage can be reduced. Therefore, a large absolute value of Δε has been required.

  Many liquid crystal compounds and liquid crystal compositions have been proposed as liquid crystal materials for VA-LCDs. Here, in order to increase Δn, it is necessary to increase the content of the liquid crystal compound having a large Δn in the liquid crystal composition, and in order to increase the absolute value of Δε, the absolute value of Δε in the liquid crystal composition is required. It is necessary to increase the content of the liquid crystal compound having a large value. However, when the content of these compounds is increased, the viscosity (η) is deteriorated and the response speed is deteriorated. Thus, a liquid crystal composition in which Δε has a negative value and Δn is large (see, for example, Patent Documents 1 to 6), Δε is a relatively large positive value, and η A liquid crystal composition having a low viscosity (see, for example, Patent Document 7) has been developed.

On the other hand, in order to produce a liquid crystal display element with higher display quality, the liquid crystal composition is required to have high chemical stability against heat, light, moisture, and the like. For example, when the chemical stability of the liquid crystal composition is low, an increase in current value or a burn-in phenomenon occurs due to heating, light irradiation, or simply over time.
In summary, there is a demand for a liquid crystal composition having high chemical stability without deteriorating the absolute value of Δε and Δn.

JP 2000-096058 A JP 2001-354967 A JP-A-11-140447 Japanese Patent Laid-Open No. 11-228966 JP-A-8-104869 Japanese Patent Application Laid-Open No. 2002-069449 JP-A-6-501517

  An object of the present invention is to use a liquid crystal composition having improved chemical stability and negative dielectric anisotropy without deteriorating the absolute values of Δn and Δε, and the liquid crystal composition. A liquid crystal display element is provided.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above problems can be solved if the liquid crystal composition contains at least two kinds of compounds having specific structures.

（式中、Ｒ^１１及びＲ^１２は互いに独立して、炭素原子数１〜８のアルキル基、炭素原子数１〜８のアルコキシ基、炭素原子数２〜８のアルケニル基又は炭素原子数２〜８のアルケニルオキシ基を表し、ａ^１１は０又は１を表し、Ａ^１１及びＡ^１２は互いに独立して

のいずれかを表す。Ａ^１１が１,４−フェニレン基である場合、ベンゼン環上に存在する１個又は２個以上の水素原子はハロゲンで置換されていてもよい。Ａ^１２が１,４−フェニレン基である場合、ベンゼン環上に存在する１個又は２個以上の水素原子はハロゲンで置換されていてもよい。）から選ばれる少なくとも一種類の化合物を含有し、
第二成分として一般式（ＩＩ）で表される化合物

（式中、Ｒ^２１及びＲ^２２は互いに独立して、炭素原子数１〜８のアルキル基又は炭素原子数１〜８のアルコキシ基を表す。）から選ばれる少なくとも一種類の化合物を含有することを特徴とする、誘電率異方性が負である液晶組成物を提供する。
さらに本発明は、前記液晶組成物を用いたことを特徴とする液晶表示素子を提供する。 That is, the present invention provides a compound represented by the general formula (I) as the first component

(In the formula, R ¹¹ and R ¹² are each independently an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or 2 to 2 carbon atoms. 8 represents an alkenyloxy group, a ¹¹ represents 0 or 1, and A ¹¹ and A ¹² independently of each other.

Represents one of the following. When A ¹¹ is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. When A ¹² is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. At least one compound selected from
Compound represented by general formula (II) as second component

(In the formula, R ²¹ and R ²² each independently represents an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms). A liquid crystal composition having a negative dielectric anisotropy is provided.
Furthermore, the present invention provides a liquid crystal display element using the liquid crystal composition.

The liquid crystal composition of the present invention is characterized by excellent chemical stability. That is, the liquid crystal composition of the present invention exhibits a liquid crystal phase with excellent liquid crystallinity and high reliability. Furthermore, the liquid crystal composition of the present invention also has an effect of hardly causing dripping marks.
For this reason, the liquid crystal display element excellent in display quality can be obtained by using the liquid crystal composition of this invention.

The liquid crystal composition having a negative dielectric anisotropy of the present invention (hereinafter referred to as the liquid crystal composition of the present invention) is at least one compound selected from compounds represented by the following general formula (I) as the first component And at least one compound selected from compounds represented by the compound represented by the following general formula (II) as the second component. By combining the compound represented by the general formula (I) and the compound represented by the general formula (II) in the liquid crystal composition, chemicals can be obtained without deteriorating the magnitudes of the absolute values of Δn and Δε. Stability can be improved. Therefore, the liquid crystal composition of the present invention has a Δn as compared with other liquid crystal compositions that do not contain both the compound represented by the general formula (I) and the compound represented by the general formula (II). And Δε both have a sufficiently large absolute value and high chemical stability.
Hereinafter, each component will be described first.

<Compound represented by formula (I)>
The liquid crystal composition of the present invention contains at least one compound selected from the compounds represented by the following general formula (I). The liquid crystal composition of the present invention may contain only one type of compound represented by the general formula (I), but preferably contains two or more types.

In general formula (I), R ¹¹ and R ¹² are independently of each other an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or a carbon atom. The alkenyloxy group of number 2-8 is represented. In the present invention, R ¹¹ and R ¹² are independently of each other an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or 2 carbon atoms. -5 alkenyloxy groups are preferable, and independently of each other, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms is more preferable. R ¹¹ and R ¹² may each be a branched chain group or a linear group, but are preferably a linear group.

In the general formula ^{(I), a 11} represents 0 or 1. In the liquid crystal composition of the present invention, when emphasizing that accelerate more the response speed, a ¹¹ is 0 is preferred. On the other _hand, when importance is attached to further enhance the _{T ni} ^{is, a 11} is 1 is preferred. Also, when emphasizing increasing the [Delta] n, a ¹¹ is 1 is preferred.

In the general formula (I), A ¹¹ and A ¹² each independently represent any of the following divalent groups having four types of 6-membered rings. Hereinafter, these four types of six-membered divalent groups may be collectively referred to as “divalent cyclic hydrocarbon group A”. When A ¹¹ is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. When A ¹² is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. In the liquid crystal composition of the present invention, A ¹¹ and A ¹² are each independently preferably a 1,4-phenylene group or a 1,4-cyclohexylene group, and the 1,4-phenylene group is one or more. May be substituted by a fluorine atom. It In the liquid crystal composition of the present invention, in the case of emphasis on lowering more the viscosity is in the general formula (I), a ¹¹ is 1 and A ¹¹ is 1,4-cyclohexylene group Is more preferable. Further, when importance is attached to further increase the refractive index anisotropy ([Delta] n) is, A ¹² is 1,4-phenylene group is more preferable.

As the compound represented by the general formula (I), R ¹¹ and R ¹² are independently of each other an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or 2 to 8 carbon atoms. Or an alkenyloxy group having 2 to 8 carbon atoms, a ¹¹ is 0, A ¹² is an unsubstituted 1,4-phenylene group, or one or more fluorine atoms are substituted. A compound which is a 1,4-phenylene group or a 1,4-cyclohexylene group, R ¹¹ and R ¹² are each independently an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, An alkenyl group having 2 to 8 carbon atoms or an alkenyloxy group having 2 to 8 carbon atoms, a ¹¹ is 1, A ¹¹ and A ¹² are independent of each other, and A ¹² is unsubstituted 1,4- Phenylene group, 1 or 2 or more The compound is preferably a 1,4-phenylene group or a 1,4-cyclohexylene group in which an elementary atom is substituted. Among them, R ¹¹ and R ¹² are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms, a ¹¹ is 0, and A ¹² is unsubstituted 1, 4 A compound that is a phenylene group, a 1,4-phenylene group or a 1,4-cyclohexylene group substituted with one or two or more fluorine atoms, R ¹¹ and R ¹² are each independently 1 carbon atom An alkyl group of ˜8 or an alkoxy group of 1 to 8 carbon atoms, a ¹¹ is 1, A ¹¹ and A ¹² are independent of each other, and A ¹² is an unsubstituted 1,4-phenylene group, Alternatively, the compound is more preferably a 1,4-phenylene group or a 1,4-cyclohexylene group in which two or more fluorine atoms are substituted.

More specifically, the compounds represented by the general formula (I) are preferably compounds represented by the following general formulas (I-1) to (I-3). In the general formula (I-1) ~ (I -3), R 11 has the same meaning as ^{R 11} in the general formula ^{(I), R 12} represents the same meaning as ^{R 12} in the general formula (I). The liquid crystal composition of the present invention preferably contains at least one compound represented by the general formulas (I-1) to (I-3) as the first component. It is more preferable to contain one or more compounds represented by (I-3).

As the compounds represented by the general formulas (I-1) to (I-3), R ¹¹ and R ¹² are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy having 1 to 8 carbon atoms. Compounds that are groups are preferred. Among these, a compound in which R ¹¹ is an alkyl group having 1 to 8 carbon atoms and R ¹² is an alkoxy group having 1 to 8 carbon atoms is more preferable.

  The content of the first component in the liquid crystal composition of the present invention (that is, the total content of one or more compounds represented by the general formula (I)) is preferably 2% by mass or more. 2-50 mass% is more preferable, 2-40 mass% is further more preferable, and 5-30 mass% is still more preferable.

<Compound represented by formula (II)>
The liquid crystal composition of the present invention contains at least one compound selected from compounds represented by the following general formula (II). The liquid crystal composition of the present invention may contain only one type of compound represented by the general formula (II), but preferably contains two or more types.

In the general formula (II), R ²¹ and R ²² each independently represent an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms. In the present invention, R ²¹ and R ²² are preferably each independently an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms. R ²¹ and R ²² may each be a branched chain group or a linear group, but are preferably a linear group.

  The content of the second component in the liquid crystal composition of the present invention (that is, the total content of one or more compounds represented by the general formula (II)) is preferably 5% by mass or more. 5-50 mass% is more preferable, 5-40 mass% is further more preferable, and 10-30 mass% is still more preferable.

<Compound represented by formula (III)>
In addition to the compound represented by the general formula (I) and the compound represented by the general formula (II), the liquid crystal composition of the present invention further includes at least one compound selected from the compounds represented by the following general formula (III). You may contain the kind of compound. However, the compound represented by the general formula (III) does not include the compound represented by the general formula (II).

In the general formula (III), R ³¹ and R ³² are independently of each other an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or a carbon atom. The alkenyloxy group of number 2-8 is represented. In the present invention, R ³¹ and R ³² are independently of each other an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or 2 carbon atoms. ˜5 alkenyloxy groups are preferred. R ³¹ and R ³² may each be a branched chain group or a linear group, but are preferably a linear group.

When the compound represented by the general formula (III) is contained, at least one kind of the compound represented by the general formula (III) contained in the liquid crystal composition of the present invention, among R ³¹ and R ³² At least one of is preferably an alkenyl group or an alkenyloxy group.

In the general formula (III), A ³¹ , A ³² and A ³³ each independently represent any of the divalent groups having the following 17 kinds of cyclic structures. Hereinafter, these 17 kinds of divalent groups having a cyclic structure may be collectively referred to as “divalent ring structure-containing group A ′”. In the present invention, A ³¹ , A ³² and A ³³ are independently of each other an unsubstituted 1,4-phenylene group, one or more fluorine atoms in the divalent ring structure-containing group A ′. 1,4-phenylene group in which is substituted, 1,4-phenylene group in which one methyl group is substituted, 1,4-cyclohexylene group or 1,4-cyclohexenylene group is preferable.

In the general formula (III), Z ³¹ and Z ³² are each independently a single bond, —CH ₂ CH ₂ —, —C≡C—, —C═N—N═C—, —CH═CH—, —CF═CF—, —CF ₂ O—, —OCF ₂ —, —COO— or —OCO— is represented. In the present invention, Z ³¹ and Z ³² are each independently a single bond, —CH ₂ CH ₂ —, —C≡C—, —COO— or —OCO—, preferably a single bond or —C≡C— Is more preferable.

In the general formula (III), a ³¹ represents 0, 1 or 2. In the present invention, a ³¹ is preferably 0 or 1. When a ³¹ is 2 and a plurality of A ³² are present, they may be the same or different. Similarly, when a plurality of Z ³² are present, they may be the same or different.

In the compound represented by the general formula (III), R ³¹ and R ³² are independently of each other an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or 2 to 8 carbon atoms. Or an alkenyloxy group having 2 to 8 carbon atoms, wherein A ³¹ , A ³² and A ³³ are independently of each other an unsubstituted 1,4-phenylene in the divalent ring structure-containing group A ′. A 1,4-phenylene group substituted with one or more fluorine atoms, a 1,4-phenylene group substituted with one methyl group, a 1,4-cyclohexylene group, or 1, A compound in which it is a 4-cyclohexenylene group, Z ³¹ and Z ³² are each independently a single bond or —C≡C—, and a ³¹ is 0 or 1 is preferable. More specifically, compounds represented by the following general formulas (III-1) to (III-15) are preferable. In the general formula (III-1) ~ (III -15), R 31 has the same meaning as ^{R 31} in the general formula ^{(III), R 32} represents the same meaning as ^{R 32} in the general formula (III).

  When the compound represented by the general formula (III) is contained, the liquid crystal composition of the present invention preferably contains 1 to 10 types of the compound represented by the general formula (III). It is more preferable to contain. Moreover, it is preferable to contain at least one compound represented by the general formulas (III-1) to (III-15). The content of the compound represented by the general formula (III) in the liquid crystal composition of the present invention is more preferably 10% by mass or more, and further preferably 20% by mass or more. Moreover, 80 mass% or less is preferable, as for content of this compound, 70 mass% or less is more preferable, and 60 mass% or less is still more preferable.

<Compound represented by formula (IV)>
In addition to the compound represented by the general formula (I) and the compound represented by the general formula (II), the liquid crystal composition of the present invention further includes at least one compound selected from the compounds represented by the following general formula (IV). You may contain the kind of compound.

In formula (IV), R ⁴¹ and R ⁴² are independently of each other an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or a carbon atom. The alkenyloxy group of number 2-8 is represented. In the present invention, R ⁴¹ and R ⁴² are independently of each other an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or 2 carbon atoms. -5 alkenyloxy groups are preferable, and independently of each other, an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms is more preferable. Each of R ⁴¹ and R ⁴² may be a branched chain group or a linear group, but is preferably a linear group.

In the general formula (IV), Z ⁴¹ and Z ⁴² each independently represent a single bond, —CH ₂ CH ₂ —, —CH═CH—, —CF═CF—, —CH ₂ O—, —OCH ₂ —. _{, -CF 2 O -, - OCF} 2 -, - COO- or an -OCO-. When there are a plurality of Z ⁴¹ , they may be the same or different. In the liquid crystal composition of the present invention, Z ⁴¹ and Z ⁴² are independently of each other a single bond, —CH ₂ CH ₂ —, —CH ₂ O—, —OCH ₂ —, —CF ₂ O—, —OCF _2. -, - COO- or -OCO-, more preferably a single _{bond, -CH 2 CH 2 -, -} CH 2 O- or -OCH ₂ - is more preferable.

In the general formula (IV), A ⁴¹ and A ⁴² each independently represent any group in the divalent cyclic hydrocarbon group A. When A ⁴¹ is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. When ^A42 is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with a halogen. Further, when there are a plurality of A ⁴¹ , they may be the same or different. In the present invention, A ⁴¹ and A ⁴² are independently of each other an unsubstituted 1,4-phenylene group, a 1,4-phenylene group in which one or more fluorine atoms are substituted, or 1,4 -A cyclohexylene group is preferable, and an unsubstituted 1, 4- phenylene group or a 1, 4- cyclohexylene group is more preferable. In the liquid crystal composition of the present invention, when importance is placed on lowering the viscosity, A ⁴¹ is more preferably a 1,4-cyclohexylene group in the general formula (IV).

In the general formula (IV), a ⁴¹ represents 1, 2 or 3, and a ⁴² represents 0 or 1.

As the compound represented by the general formula (IV), R ⁴¹ and R ⁴² are each independently an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, or 2 to 8 carbon atoms. Or an alkenyloxy group having 2 to 8 carbon atoms, Z ⁴¹ and Z ⁴² are each independently a single bond, —CH ₂ CH ₂ —, —CH ₂ O— or —OCH ₂ —, A ⁴¹ and A ⁴² are each independently an unsubstituted 1,4-phenylene group or 1,4-cyclohexylene group, a ⁴¹ is 1, 2 or 3, and a ⁴² is 0 or 1 Is preferred.

More specifically, the compounds represented by the general formula (IV) are preferably compounds represented by the following general formulas (IV-1) to (IV-12). In the general formula (IV-1) ~ (IV -12), R 41 has the same meaning as ^{R 41} in the general formula ^{(IV), R 42} has the same meaning as ^{R 42} in formula (IV), A ⁴¹ has the same meaning as ^{a 41} in the general formula ^{(IV), a 42} represents the same meaning as ^{a 42} in the general formula (IV). The liquid crystal composition of the present invention preferably contains at least one compound represented by the general formulas (IV-1) to (IV-12) as the fourth component. The general formula (IV-1) It is more preferable that one type or two or more types of compounds represented by (IV-12) are contained.

As the compounds represented by the general formulas (IV-1) to (IV-12), A ⁴¹ and A ⁴² are independently of each other an unsubstituted 1,4-phenylene group, one or more fluorine atoms. An 1,4-phenylene group or 1,4-cyclohexylene group substituted with an atom is preferable, and an unsubstituted 1,4-phenylene group or 1,4-cyclohexylene group is more preferable.

As the compounds represented by the general formulas (IV-1) to (IV-12), R ⁴¹ and R ⁴² are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy having 1 to 8 carbon atoms. A compound in which R ⁴¹ is an alkyl group having 1 to 8 carbon atoms and R ⁴² is an alkoxy group having 1 to 8 carbon atoms is more preferable.

As the compounds represented by the general formulas (IV-1) to (IV-12), compounds represented by the following general formulas (IV-101) to (IV-154) are particularly preferable. In the general formula (IV-101) ~ (IV -154), R 41 has the same meaning as ^{R 41} in the general formula ^{(IV), R 42} represents the same meaning as ^{R 42} in the general formula (IV). As the compounds represented by the general formulas (IV-101) to (IV-154), R ⁴¹ and R ⁴² are each independently an alkyl group having 1 to 8 carbon atoms or an alkoxy having 1 to 8 carbon atoms. A compound in which R ⁴¹ is an alkyl group having 1 to 8 carbon atoms and R ⁴² is an alkoxy group having 1 to 8 carbon atoms is more preferable.

  The content of the fourth component in the liquid crystal composition of the present invention (that is, the total content of one or more compounds represented by the general formula (IV)) is preferably 3% by mass or more. 3-70 mass% is more preferable, 10-60 mass% is further more preferable, and 20-60 mass% is still more preferable.

  When the liquid crystal composition of the present invention contains a fourth component, the total content of the first component, the second component, and the fourth component in the liquid crystal composition of the present invention is 10% by mass. Preferably, it is 10-80 mass%, more preferably 40-80 mass%.

  The liquid crystal composition of the present invention contains ordinary nematic liquid crystals, smectic liquid crystals, cholesteric liquid crystals, antioxidants, ultraviolet absorbers, polymerizable monomers, etc., in addition to the above compounds, as long as the effects of the present invention are not impaired. can do. However, the liquid crystal composition of the present invention preferably does not contain a liquid crystal compound having a partial structure in which heteroatoms such as —O—O—, —O—S—, and —S—S— are directly bonded to each other.

  The polymerizable monomer that can be contained in the liquid crystal composition of the present invention is preferably a photopolymerizable monomer. When the photopolymerizable monomer is contained, the content of the photopolymerizable monomer in the liquid crystal composition of the present invention is preferably 500 to 5000 ppm. Examples of the photopolymerizable monomer include monomers having a polymerizable unsaturated double bond such as acrylic acid ester and methacrylic acid ester.

When the liquid crystal composition of the present invention is used for an active matrix drive liquid crystal display device, T _ni of the liquid crystal composition of the present invention is preferably 60 to 120 ° C, and the lower limit is more preferably 65 ° C, and 70 ° C. Is particularly preferred. As an upper limit, 90 degreeC is more preferable and 80 degreeC is especially preferable. Δε at 25 ° C. is preferably −2.0 to −6.0, more preferably −2.5 to −5.0, and particularly preferably −2.5 to −3.5. preferable. Δn at 25 ° C. is preferably 0.08 to 0.13, and more preferably 0.09 to 0.12. More specifically, Δn at 25 ° C. is preferably 0.10 to 0.12 when corresponding to a thin cell gap, and is 0.08 to 0.10 when corresponding to a thick cell gap. Is preferred. The viscosity (η) at 20 ° C. is preferably 10 to 30 mPa · s, more preferably 10 to 25 mPa · s, and particularly preferably 10 to 20 mPa · s.

When the liquid crystal composition of the present invention is used for a passive matrix drive liquid crystal display element, T _ni of the liquid crystal composition of the present invention is preferably 60 to 120 ° C. for consumer use, and the lower limit is more preferably 65 ° C. Preferably, 70 ° C. is particularly preferable. As an upper limit, 90 degreeC is more preferable and 80 degreeC is especially preferable. In in-vehicle applications, the lower limit is more preferably 90 ° C, and particularly preferably 100 ° C. As an upper limit, 115 degreeC is more preferable and 105 degreeC is especially preferable. Δn at 25 ° C. is preferably 0.08 to 0.13, particularly preferably 0.08 to 0.11 for low duty driving. Further, for high duty driving, it is preferably 0.13 to 0.20, and particularly preferably 0.15 to 0.18. Δε at 25 ° C. is preferably −2.0 to −7.0, and particularly preferably −2.5 to −5.5 in the low duty drive. Η at 20 ° C. is preferably 10 to 40 mPa · s, more preferably 10 to 30 mPa · s, and particularly preferably 10 to 25 mPa · s.

T _ni , Δε, and Δn of the liquid crystal composition of the present invention are suitable for the intended use of the liquid crystal composition by adjusting the composition ratio of various compounds including the first component and the second component, respectively. The range can be adjusted as appropriate. As the liquid crystal composition of the present invention, T _ni is 70 ° C. to 120 ° C., Δε at 25 ° C. and 589 nm is −1.5 to −8.0, and Δn at 25 ° C. and 1 kHz is 0.080 to It is preferably 0.250. When T _ni , Δε, and Δn are within these ranges, they can be suitably used for various applications.

  Further, by using the liquid crystal composition of the present invention, a liquid crystal display element having a vertical alignment ability can be produced. For example, by using the liquid crystal composition of the present invention, a liquid crystal display element having a pretilt angle of 80 ° to 90 ° can be manufactured.

  EXAMPLES Hereinafter, although an Example etc. are given and this invention is further explained in full detail, this invention is not limited to these Examples etc. Further, “%” in the compositions of the following Examples and Comparative Examples means “% by mass”.

Terms used in the examples are described below.
T _ni : Nematic-isotropic transition temperature [° C.]
Δn: refractive index anisotropy (589 nm, 25 ° C.)
Δε: dielectric anisotropy (1 kHz, 25 ° C.)
η: Bulk flow viscosity [mPa · s] (20 ° C.)
Response speed: Liquid crystal composition was injected into a vertical alignment cell with a gap of 3.5 μm and a pretilt angle of 89 °, and measured with a 5 V, 100 Hz rectangular wave.

The following abbreviations are used in the compound descriptions in the examples.
Side chain abbreviations are shown below.
-n (number): -C _n H _{2n + 1} (the alkyl side chain is a number, and R is representative for representation)
-On: -OC _n H _{2n + 1}
-ndm:-(C _n H _{2n + 1} -C = C- (CH ₂ ) _m-1 )
ndm-: C _n H _{2n + 1} -C = C- (CH ₂ ) _m-1-
-nOm:-(CH ₂ ) _n OC _m H _{2m + 1}
nOm-: C _n H _{2n + 1} O (CH ₂ ) _m-
-Od (m) n: -O ( C n H 2n + 1 -C = C- (CH 2) m-2)
d (m) nO-: C _n H _{2n + 1} -C = C- (CH ₂ ) _m-2 O-

The linking group abbreviations are shown below.
-T-: -C≡C-
-2-: -CH ₂ CH ₂ -
-1O-: -CH ₂ -O-
-O1-: -O-CH _2-
The ring abbreviations are shown below.

(Measurement method of current value)
With respect to the liquid crystal composition injected into the vertical alignment cell (cell gap: 3.5 μm), a light resistance test for 16 hours was performed with a light resistance tester at an intensity of 500 W / m ² . The current value before the start of the light resistance test was taken as the initial current value, and the current value at the end of the light resistance test was taken as the panel current value. Each current value was measured at 2.5 V and 200 Hz.

(Evaluation of seizure unevenness level)
A rectangular wave of 5 V and 100 Hz was applied to the liquid crystal composition injected into the vertical alignment cell (cell gap: 3.5 μm) for 24 hours. After 24 hours, the seizure level was visually observed with no voltage applied, and evaluated according to the following four levels.
1: Severe seizure 2: Seizure 3: Extremely slight seizure 4: No seizure

(Evaluation of dripping unevenness (trace) level)
One drop of the liquid crystal composition was sandwiched between two glass slides, and uneven color spreading concentrically was observed and evaluated in the following four stages.
1: Severe unevenness 2: Unevenness 3: Extremely slight unevenness 4: No unevenness

(Examples 1-2 and Comparative Example 1)
A liquid crystal composition having the composition shown in Table 1 was produced, and T _ni , Δε, Δn, and η of the liquid crystal composition were measured. Furthermore, the initial current value of the obtained liquid crystal composition and the panel current value after the light test were measured, and the image sticking unevenness and the drop unevenness (droplet mark) were evaluated. The measurement and evaluation results are shown in Table 1.

The liquid crystal compounds of Examples 1 and 2 are one of the side chains at both ends in the compound represented by the general formula (II) among the compounds represented by the general formula (III) in the liquid crystal compound of the comparative example 1. Is a compound in which an alkenyl group is replaced with a compound represented by the general formula (II). These three liquid crystal compositions have substantially the same Δn, Δε, η, and T _ni , and the initial current values are also substantially the same. However, in the liquid crystal compositions of Examples 1 and 2, all of the panel current value, the image sticking unevenness, and the drop mark unevenness were improved as compared with the liquid crystal composition of Comparative Example 1. From these results, a compound represented by the general formula (II) in which both ends of the linked cyclohexylene group are alkyl groups or alkoxy groups and a compound represented by the general formula (I) are used in combination. As a result, the chemical stability of the liquid crystal composition is improved. As a result, it is possible to suppress an increase in the current value after the light resistance test, to suppress the unevenness in image sticking, and to improve the unevenness in the drop mark. It was.

  The liquid crystal composition of the present invention is useful for liquid crystal display elements, useful for active matrix driving liquid crystal display elements and passive matrix driving liquid crystal display elements, and particularly useful for passive matrix driving liquid crystal display elements. Further, it can be used for a liquid crystal display element for VA mode, PSVA mode, IPS mode or ECB mode.

Claims (13)

Compound represented by general formula (I) as first component

(In the formula, R ¹¹ and R ¹² are each independently an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or 2 to 2 carbon atoms. 8 represents an alkenyloxy group, a ¹¹ represents 0 or 1, and A ¹¹ and A ¹² independently of each other.

Represents one of the following. When A ¹¹ is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. When A ¹² is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. At least one compound selected from
Compound represented by general formula (II) as second component

(In the formula, R ²¹ and R ²² each independently represents an alkyl group having 1 to 8 carbon atoms or an alkoxy group having 1 to 8 carbon atoms). A liquid crystal composition having a negative dielectric anisotropy, characterized by: As the third component, a compound represented by the general formula (III)

(In the formula, R ³¹ and R ³² are each independently an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or 2 to 2 carbon atoms. 8 represents an alkenyloxy group, and A ³¹ , A ³² and A ³³ are independently of each other.

Z ³¹ and Z ³² each independently represent a single bond, —CH ₂ CH ₂ —, —C≡C—, —C═N—N═C—, —CH═CH—, — CF═CF—, —CF ₂ O—, —OCF ₂ —, —COO— or —OCO—, a ³¹ represents 0, 1 or 2, and when a plurality of A ³² are present, they may be the same They may be different from each other, and when there are a plurality of Z ³² , they may be the same or different. However, the compound represented by the general formula (II) is excluded. The liquid crystal composition having a negative dielectric anisotropy according to claim 1, comprising at least one compound selected from the group consisting of:   The liquid crystal composition according to claim 1 or 2, wherein the content of the first component is 2% by mass to 80% by mass.   The dielectric anisotropy according to any one of claims 1 to 3, wherein the first component contains two or more compounds selected from the compounds represented by the general formula (I). Liquid crystal composition.   The dielectric anisotropy according to any one of claims 1 to 4, wherein the second component contains two or more compounds selected from compounds represented by the general formula (II). Liquid crystal composition. Compound represented by general formula (IV) as the fourth component

Wherein R ⁴¹ and R ⁴² are independently of each other an alkyl group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkenyl group having 2 to 8 carbon atoms, or 2 to 2 carbon atoms. 8 represents an alkenyloxy group, and Z ⁴¹ and Z ⁴² are each independently a single bond, —CH ₂ CH ₂ —, —CH═CH—, —CF═CF—, —CH ₂ O—, —OCH _{2. -, - CF 2 O -,} - OCF 2 -, - COO- or an ^{-OCO-, a 41} and ^{a 42} independently of one another,

A ⁴¹ represents 1, 2 or 3, and a ⁴² represents 0 or 1. When a plurality of A ⁴¹ are present, they may be the same or different, and when a plurality of Z ⁴¹ are present, they may be the same or different. When A ⁴¹ is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with halogen. When ^A42 is a 1,4-phenylene group, one or more hydrogen atoms present on the benzene ring may be substituted with a halogen. The liquid crystal composition having a negative dielectric anisotropy according to any one of claims 1 to 5, comprising at least one compound selected from the group consisting of:   The liquid crystal composition according to claim 6, wherein the total amount of the first component, the second component, and the fourth component is 10% by mass to 80% by mass.   The nematic-isotropic transition temperature is 70 ° C to 120 ° C, the dielectric anisotropy is -1.5 to -8.0, and the birefringence is 0.080 to 0.250. 2. A liquid crystal composition having a negative dielectric anisotropy according to item 1.   The liquid crystal composition having a negative dielectric anisotropy according to any one of claims 1 to 8, comprising 500 to 5000 ppm of a photopolymerizable monomer.   A liquid crystal display element using the liquid crystal composition having a negative dielectric anisotropy according to claim 1.   The liquid crystal display element according to claim 10, wherein the pretilt angle is 80 ° to 90 °.   The liquid crystal display element according to claim 10 or 11, which is of an active matrix drive type.   The liquid crystal display element according to claim 10 or 11, which is a passive matrix drive type.