JP5141947B2 - Nematic liquid crystal composition and liquid crystal display device using the same - Google Patents

Description

  The present invention relates to a nematic liquid crystal composition that satisfies various characteristics of an electro-optic display element and has a wide nematic temperature range, high refractive index anisotropy, low viscosity, and low ion density, and a liquid crystal display element using the same.

  A typical liquid crystal display element is a TN-LCD (twisted nematic liquid crystal display element), which is used in watches, calculators, electronic notebooks, and the like. On the other hand, with the expansion of display capacity, STN (Super Twisted Nematic) -LCD has been developed and is widely used in displays for high information processing such as mobile phones.

  Recently, display characteristics such as high contrast and high response speed are required for portable terminal display (Personal Digital Assistance) and the like. High-speed response is achieved by lowering the viscosity of the liquid crystal and reducing the thickness (d) of the liquid crystal phase held between the glass substrates. To avoid a decrease in contrast due to variations in retardation (Δn × d). A liquid crystal having a low viscosity and a larger refractive index anisotropy (Δn) is desired. On the other hand, when the liquid crystal display element has a large amount of ions in the liquid crystal phase held between the glass substrates, the effective voltage applied to the liquid crystal is consumed by the movement of ions, so that the driving voltage varies depending on the frequency. There is a thing. Therefore, when high time-division driving having a characteristic that the effective frequency of each pixel is generally different, there is a problem that display disappearance / display appearance called crosstalk or crosstalk occurs. In other words, reducing the ion density when a liquid crystal display element is used is an important factor for obtaining good contrast.

  Examples of the liquid crystal composition having a large Δn include a liquid crystal composition containing N-phenyl-3-phenyl-3-hydroxy-2-propylene-1-1-1imine (see Patent Document 1) and a fluorotolane compound. A liquid crystal composition (see Patent Document 2) is disclosed. However, a liquid crystal compound having a high Δn generally has a high viscosity, and since there is a trade-off relationship between increasing Δn of the liquid crystal composition and decreasing the viscosity, there is a drawback that the viscosity of the liquid crystal composition increases. . Accordingly, a liquid crystal composition containing a 4-substituted phenylcrotyl ether derivative (see Patent Document 3), a liquid crystal composition containing a compound having a tran-4,4′-diyl structure (see Patent Document 4), and a dialkenyltolane derivative A liquid crystal composition having a relatively low viscosity in addition to a high Δn, such as a liquid crystal composition containing a compound (see Patent Document 5), is disclosed. However, the effect of improving the trade-off between viscosity and Δn is still insufficient, and does not satisfy the characteristics required for recent high-speed response and high-contrast liquid crystal display elements. Furthermore, the shift to high time-division driving with an increase in the amount of display information has caused a problem of deterioration in display quality due to the influence of the amount of ions in the liquid crystal cell. That is, a liquid crystal composition having high Δn and lower viscosity and capable of reducing the amount of ions of the liquid crystal display element has been desired. A liquid crystal composition satisfying these simultaneously with a specific combination of liquid crystal compounds is obtained. The method was not yet known, and its development was desired.

Japanese Patent Laid-Open No. 9-124577 JP-A 63-287737 JP-A-62-277333 JP-A-10-88140 Japanese Patent Laid-Open No. 10-017500

  The problem to be solved by the present invention is a nematic liquid crystal composition having a low viscosity, a large refractive index anisotropy and a low ion density when used as a liquid crystal display device, and an excellent high-speed response by using this composition. An object of the present invention is to provide a liquid crystal display element in which the contrast is improved by suppressing the frequency change of the driving voltage.

As a result of studying liquid crystal compositions using various liquid crystal compounds in order to solve the above-mentioned problems, the present invention has been completed.
That is, the general formula (1) is used as the first component.

（式中、R₁は、炭素数1〜8のアルキル基、炭素数1〜8のアルコキシ基、炭素数2〜8のアルケニル基又は炭素数2〜8のアルケニルオキシ基を表す。）
で表される化合物1種以上を、2〜20質量%含有し、
第二成分として一般式(２)

(In the formula, R ₁ represents 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.)
Containing one or more compounds represented by 2-20% by mass,
General formula (2) as the second component

（式中、R₂は炭素数1〜8のアルキル基を表す。）で表される化合物1種以上を、8〜38質量%含有し、さらに第一成分及び第二成分の含有量の合計が10〜40質量%であって、
第三成分として一般式（３）

(In the formula, R ₂ represents an alkyl group having 1 to 8 carbon atoms.) 8 to 38% by mass of the compound represented by 1 to 8%, and the total content of the first component and the second component Is 10-40% by mass,
General formula (3) as the third component

（式中、R₃及びR₄はそれぞれ独立的に炭素数1〜8のアルキル基、炭素数1〜8のアルコキシ基、炭素数2〜8のアルケニル基又は炭素数2〜8のアルケニルオキシ基を表し、Z₁は-CH₂CH₂-、-CH=CH-、-COO-、-OCO-、又は単結合を表し、Y₁〜Y₈はそれぞれ独立的に水素原子、フッ素原子又はメチル基を表し、Aは1,4-フェニレン基又は1,4-シクロヘキシレン基を表す。）で表される化合物1種以上を、10〜40質量%含有し、
第四成分として、250〜400nmにおける最大吸収波長が290nm以上である紫外線吸収剤を0.001〜5質量%含有し、該紫外線吸収剤が分子構造中に水酸基を有する場合、全ての水酸基が分子内水素結合を形成していることを特徴とするネマチック液晶組成物及び当該組成物を用いた液晶表示素子を提供する。

(In the formula, R ₃ and R ₄ 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. Z ₁ represents —CH ₂ CH ₂ —, —CH═CH—, —COO—, —OCO—, or a single bond, and Y _{1 to} Y ₈ each independently represent a hydrogen atom, a fluorine atom, or methyl. A group, and A represents a 1,4-phenylene group or a 1,4-cyclohexylene group).
As a fourth component, 0.001 to 5% by mass of an ultraviolet absorber having a maximum absorption wavelength at 250 to 400 nm of 290 nm or more, and when the ultraviolet absorber has a hydroxyl group in the molecular structure, all the hydroxyl groups are intramolecular hydrogen Provided are a nematic liquid crystal composition characterized by forming a bond and a liquid crystal display device using the composition.

  The nematic liquid crystal composition of the present invention is characterized by having a high refractive index anisotropy and a low viscosity and a low ion density when a liquid crystal display device is obtained. Therefore, it is suitable as a member of a liquid crystal display element having a thin cell gap, and has a feature that it is excellent in high-speed response when it is used as a liquid crystal display element, and at the same time, frequency dependence of driving voltage is small. Therefore, a constant drive voltage can be maintained with respect to the frequency distribution of each pixel in the high time division drive, and display unevenness is greatly reduced, so that a good display quality can be maintained, excellent in contrast and response speed, TN, STN It is useful for liquid crystal display elements such as.

An example of the present invention will be described below.
In the present invention, the compound represented by the general formula (1) is contained as the first component in an amount of 2 to 20% by mass, and the content is more preferably in the range of 2 to 15% by mass, and 3 to 10% by mass. % Range is particularly preferred.

In the compound represented by the general formula (1), when R ₁ has a small number of carbon atoms, it is advantageous for lowering the viscosity of the liquid crystal composition, but at the same time, the nematic phase-isotropic liquid phase transition temperature is lowered. When R ₁ has a large number of carbon atoms, the viscosity of the liquid crystal composition is adversely affected, but the influence on the nematic phase-isotropic liquid phase transition temperature is reduced. That is, the characteristics of the present invention can be effectively realized in a compound in which the carbon number of R ₁ is in a specific range in the general formula (1). R ₁ is preferably an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, more preferably an alkyl group having 2 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms, specifically, Compounds represented by formula (1-a) to formula (1-i) are more preferable.

On the other hand, among the compounds represented by the formulas (1-a) to (1-i), a compound in which R ₁ represents an alkyl group is more preferable. Therefore, Formula (1-a) to Formula (1-d) are particularly preferable, and Formula (1-b) and Formula (1-d) are most preferable.

The compound represented by the general formula (2) is contained as the second component in an amount of 8 to 38% by mass, and the content is more preferably in the range of 8 to 25% by mass, and in the range of 10 to 15% by mass. It is particularly preferred. In the compound represented by the general formula (2), when R ₂ has a small number of carbon atoms as in R ₁ , it is advantageous for lowering the viscosity of the liquid crystal composition, but at the same time nematic phase-isotropic liquid phase transition temperature. When the carbon number of R ₂ is large, the viscosity of the liquid crystal composition is adversely affected, but the influence on the nematic phase-isotropic liquid phase transition temperature is reduced. Therefore, the characteristics of the present invention can be effectively realized in a compound in which the carbon number of R ₂ is in a specific range. R ₂ is preferably an alkyl group having 2 to 7 carbon atoms, more preferably an alkyl group having 2 to 5 carbon atoms, specifically, compounds represented by the following formulas (2-a) to (2-f) Is particularly preferred.

Of the compounds represented by formula (2-a) to formula (2-f), formula (2-a), formula (2-b) and formula (2-d) are particularly preferred.
Further, the total content of the general formula (1) and the general formula (2) which are compounds having a large dielectric anisotropy is 10 to 40% by mass, but is more preferably in the range of 13 to 25% by mass. preferable.

As the third component, 10 to 40% by mass of one or more compounds selected from general formula (3) is contained, but when A represents a 1,4-cyclohexylene group, Y _{1 to} Y ₈ represent a hydrogen atom. More preferably, in this structure, R ₃ represents an alkyl group or alkoxy group having 1 to 8 carbon atoms and R ₄ represents an alkyl group having 1 to 8 carbon atoms (hereinafter, this group of compounds is referred to as third referred to component -1), more preferably an alkyl group of R ₃ is C1-5 alkyl or and R ₄ represents an alkoxy group of carbon atoms of 1 to 5 carbon atoms, specifically below the Particularly preferred are compounds represented by formulas (3-a1) to (3-h4).

Among these, as the third component-1, formulas (3-c1) to (3-d4), formulas (3-e1) to (3-e3) and formulas (3-g1) to (3-g4) are preferable. , Formula (3-c2), Formula (3-c3), Formula (3-d1) to (3-d3), Formula (3-e1), Formula (3-e2), Formula (3-g1) to (3- 3-g3) is more preferable, and formulas (3-c2), (3-d1), and (3-g1) to (3-g3) are more particularly preferable.

When A represents a 1,4-phenylene group, it is preferable that at least one of Y _{1 to} Y ₈ represents a fluorine atom, Z ₁ represents a single bond, and R ₃ and R ₄ are each independently carbon. It is preferable to represent an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 2 to 8 carbon atoms, more preferably an alkyl group having 2 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms. 3rd component-2). Specifically, compounds represented by the following general formulas (3-i1) to (3-m6) are particularly preferable.

(R ₃ and R ₄ each independently represent a linear alkyl group having 1 to 8 carbon atoms or a linear alkenyl group having 2 to 8 carbon atoms.)
Among them, the third component-2 includes general formula (3-i1), general formula (3-i3), general formula (3-j1), general formula (3-k1), general formula (3-k2), General formulas (3-m1) to (3-m6) are preferred, and general formulas (3-i1), general formulas (3-i3), general formulas (3-k1), and general formulas (3-k2) are more preferred. The general formula (3-i1) and the general formula (3-k1) are particularly preferable.

In the third component-2, when at least one of R ₃ and R ₄ represents an alkenyl group, it is preferably a structure represented by the following formulas (a) to (e).

(The structural formula is assumed to be linked to the ring at the right end.) Among these, the structure represented by (a), (b) or (e) is more preferred, and (a) or (b) is particularly preferred. .

  The content ratio of the third component is preferably in the range of 10 to 35% by mass, more preferably in the range of 10 to 30%, and the composition ratio is preferably composed only of the third component-1. More preferably, the third component-1 and the third component-2 are used, and the third component-2 alone is particularly preferable.

As the four components, the maximum absorption wavelength at 250 to 400 nm is 290 nm or more, and when the molecular structure has a hydroxyl group, all of them contain an ultraviolet absorber that forms an intramolecular hydrogen bond. Specifically, a compound selected from the group of compounds having a partial structural formula consisting of general formula (4), formula (5), general formula (6) and formula (7) is preferable as the ultraviolet absorber.
Compound having partial structure represented by general formula (4)

(In the formula, R ₅ represents a single bond or an alkylene group having 1 to 20 carbon atoms, and the carbon atom in the alkylene group may be substituted by halogen, and one or two or more in the alkylene group) -CH ₂ -may be substituted by -O-, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O- as those in which oxygen atoms are not directly bonded to each other. In the alkylene group, one or more of —CH ₂ CH ₂ — may be substituted by —CH═CH—, and L ₁ and L ₂ are each independently a hydrogen atom, a hydroxyl group, When an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 1 to 20 carbon atoms is represented, but at least one of L ₁ and L ₂ is a hydroxyl group, and the wavy line represents a connecting portion of the partial structure, but is not connected to represent a hydrogen atom.) at least one of L ₁ or L ₂ in the general formula (4) represents a hydroxyl group, hydrogen atom of the in hydroxyl nitrogen atom of the triazole ring Form hydrogen bonds.
The compound having the partial structure represented by the general formula (4) is represented by the general formula (8)

(In the formula, R ₅ represents a single bond or an alkylene group having 1 to 20 carbon atoms, and the carbon atom in the alkylene group may be substituted by halogen, and one or two or more in the alkylene group) -CH ₂ -may be substituted by -O-, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O- as those in which oxygen atoms are not directly bonded to each other. In the alkylene group, one or more of —CH ₂ CH ₂ — may be substituted by —CH═CH—, and L _{5 to} L ₉ are each independently a hydrogen atom, a hydroxyl group, Represents a fluorine atom, a chlorine atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with at least one halogen, or an alkenyl group having 2 to 20 carbon atoms which may be substituted with at least one halogen, and One or two or more —CH ₂ — present in the group independently represent —O— or —N— as oxygen atoms are not directly bonded to each other. , -S-, -CO-, -COO-, -OCO- or -OCO-O-, but at least one of L ₅ and L ₆ is a hydroxyl group, and L _{10 to} L ₁₃ Each independently represents a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with at least one halogen, or 2 carbon atoms which may be substituted with at least one halogen. Represents one to two alkenyl groups, and one or two or more —CH ₂ — present in these groups are each independently —O—, —N—, —, wherein oxygen atoms are not directly bonded to each other. A compound represented by S-, -CO-, -COO-, -OCO- or -OCO-O-) may be more preferable.

In the general formula (4), R ₅ is preferably a single bond or a linear or branched alkylene group having 1 to 20 carbon atoms, more preferably a single bond or a linear alkylene group having 1 to 5 carbon atoms, and more preferably a single bond. preferable. L ₇ and L ₉ are each independently preferably a linear or branched alkyl group having 1 to 20 carbon atoms, and —CH ₂ — in the group may be substituted by —COO— or —OCO—, One of L ₅ and L ₆ preferably represents a hydroxyl group and the other represents a hydrogen atom.
Specifically, the compounds represented by the general formula (4) are represented by the general formulas (4-a) to (4-h).

A compound represented by the formula (wherein X ₁ represents a hydrogen atom, a fluorine atom or a chlorine atom) is particularly preferred. Of the general formulas (4-a) to (4-h), the general formula (4-a) or the general formula (4-b) is particularly preferable.
Compound having partial structure represented by formula (5)

(The wavy line represents the connecting part of the partial structure, but when not connected, it represents a hydrogen atom.)
The compound having a partial structure represented by the formula (5) is represented by the general formula (9)

(Wherein R ₆ is an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms substituted by at least one halogen, an alkenyl group having 2 to 20 carbon atoms, or a carbon substituted by at least one halogen. Represents an alkenyl group having a number of 2 to 20, and one or two or more CH2 groups present in these groups are each independently -O-, -N-,- May be substituted by S-, -CO-, -COO-, -OCO- or -OCO-O-, C and D represent phenyl groups, each independently at least one of which is present in these groups More preferably, the hydrogen atom is an alkyl group or alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, a fluorine atom, a chlorine atom, or —OCF ₃ . ,
General formula (5-a)

(Wherein R ₆ is substituted by an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms substituted by at least one halogen, an alkenyl group having 2 to 20 carbon atoms, or at least one halogen. Represents an alkenyl group having 2 to 20 carbon atoms, and one or two or more CH2 groups present in these groups are each independently -O-, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O- may be substituted).
Compound having partial structure represented by general formula (6)

(Wherein L ₃ and L ₄ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 1 to 20 carbon atoms, but at least one of L ₃ and L ₄ Is a hydroxyl group, and the wavy line represents a connecting part of the partial structure, but represents a hydrogen atom when not connected.)
The compound having the partial structure represented by the general formula (6) is represented by the general formula (10)

(In the formula, L ₁₄ and L ₁₅ each independently represent a hydroxyl group or a hydrogen atom, but at least one is a hydroxyl group, and L _{16 to} L ₁₉ each independently represent —SO ₃ Na, —SO ₃ H, An alkyl group having 1 to 20 carbon atoms which may be replaced by at least one halogen, an alkenyl group having 2 to 20 carbon atoms which may be replaced by at least one halogen, and one existing in these groups Or two or more CH ₂ groups independently represent oxygen atoms not directly bonded to each other as —O—, —N—, —S—, —CO—, —COO—, —OCO— or —OCO—. More preferably a compound represented by the general formula (6-a):

(In the formula, L ₂₉ represents a hydrogen atom or a hydroxyl group, and each X ₂ independently represents —SO ₃ Na, —SO ₃ H, or an alkyl group having 1 to 20 carbon atoms which may be replaced by at least one halogen. Represents an alkenyl group having 2 to 20 carbon atoms which may be replaced by at least one halogen, and one or two or more CH2 groups present in these groups are each independently oxygen atoms directly bonded to each other In particular, a compound represented by -O-, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O-) is particularly preferable.
Compound having partial structure represented by formula (7)

(In the formula, the wavy line represents the connecting part of the partial structure, but when not connected, it represents a hydrogen atom.)
The compound having a partial structure represented by the formula (7) is represented by the general formula (11)

(Wherein a, b and c each independently represents an integer of 0 or 1, and L _{20 to} L ₂₈ are each independently substituted with a hydrogen atom, a fluorine atom, a chlorine atom, a hydroxyl group and at least one halogen. Represents an optionally substituted alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms that may be substituted with at least one halogen, and one or more CH present in these groups _{The two} groups are each independently replaced by -O-, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O-, as oxygen atoms are not directly bonded to each other. However, at least one of L ₂₁ , L ₂₂ , L ₂₄ , L ₂₅ , L ₂₇ and L ₂₈ represents a hydroxyl group) is more preferred, and a compound represented by the general formula (7-a)

(式中、X₂は一般式(6-a)中のX₂と同等の構造を表す)で表される化合物が特に好ましい。

A compound represented by the formula (wherein X ₂ represents a structure equivalent to X ₂ in the general formula (6-a)) is particularly preferred.

The fourth component is preferably composed of a plurality of compounds, but in this case, it is preferable to contain at least one compound represented by the general formula (8).
In the present invention, the ultraviolet absorber is contained in an amount of 0.001 to 5% by mass, preferably 0.001 to 2% by mass, and more preferably 0.001 to 1% by mass.
In the present invention, as the fifth component, general formula (12-a), general formula (12-b), general formula (12-c), general formula (12-d), general formula (12-e), general formula (12-f), general formula (12-g) or general formula (12-h)

Wherein R ₇ and R ₈ 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. Y _{9 to} Y ₁₂ each independently represents a hydrogen atom, a fluorine atom or a methyl group, and Z ₂ represents —CH ₂ CH ₂ —, —CH═CH—, —COO—, —OCO—, or a single atom. In general formulas (12-g) and (12-h), single bonds are excluded, Z ₃ represents —C≡C—, —COO— or —OCO—, and Z ₄ represents — It is also preferable to contain a compound represented by COO- or -OCO-), but it is more preferably selected in the range of 1 to 20 types, and particularly preferably in the range of 1 to 15 types. . The content of general formula (12-a) to general formula (12-h) is preferably in the range of 20 to 90% by mass, more preferably in the range of 30 to 80% by mass, and in the range of 40 to 70%. Particularly preferred. In the general formulas (12-a) to (12-h), R ₇ and R ₈ are each independently a linear alkyl group having 1 to 8 carbon atoms or a linear alkenyl group having 2 to 8 carbon atoms. In the case of representing an alkenyl group, it is more preferable to represent a structure represented by the above formulas (a) to (e).
Among the general formulas (12-a) to (12-h), the general formula (12-a), the general formula (12-b), the general formula (12-c), and the general formula (12-e) ) Is more preferable.

The liquid crystal composition of the present invention has the characteristics that it has low viscosity and high Δn, and has a low ion density when a liquid crystal display device is constructed, and can suppress a change in frequency of a driving voltage at room temperature to high temperature. Therefore, it is possible to maintain a stable display state with respect to the frequency distribution of each pixel due to high time division driving of the liquid crystal display element, in addition to high-speed response and high contrast, display appearance and display disappearance phenomenon called crosstalk It is possible to provide a liquid crystal display element with improved characteristics. The ion density when injected into a glass cell for a liquid crystal display having a rubbed polyimide alignment film is preferably 10 [nC / cm ² ] or less, more preferably 6 [nC / cm ² ] or less. It is preferably 4 [nC / cm ² ] or less. The dielectric anisotropy (Δε) is preferably 5 or more and 35 or less, but more preferably 5 or more and 25 or less. Frequency dependence of drive voltage at room temperature ΔV / Δf [(Vth [5000Hz] −Vth [64Hz]) / Vth [64Hz] × 100%] is preferably 2% or less, more preferably 1.0% or less, and 0.6% or less. Particularly preferred is 0.4% or less.

  The liquid crystal composition of the present invention can provide a liquid crystal composition having excellent properties other than those described above, but the nematic phase upper limit temperature is preferably 60 ° C or higher, more preferably 80 ° C or higher. 90 ° C. or higher is particularly preferable. Δn is preferably in the range of 0.10 to 0.26, a range of 0.10 to 0.16 is preferred for TN-LCD cell thickness design, and a range of 0.13 to 0.24 is preferred for STN-LCD cell thickness design. In the case of importance, it is particularly preferably in the range of 0.15 to 0.22.

  The liquid crystal composition of the present invention may contain a nematic liquid crystal, a smectic liquid crystal, a cholesteric liquid crystal, a dichroic dye, etc. in addition to the above compounds, and further contains an antioxidant for the purpose of improving heat resistance. You may do it. As the antioxidant, a commercially available product can be used. Examples include IRGANOX 1010 and IRGANOX 1076 manufactured by Ciba Specialty Chemicals, Sumilizer-GS, Sumilizer-GP, and Sumilizer-GA80 manufactured by Sumitomo Chemical. Further, a chiral agent may be added to prevent the reverse twist domain of TN-LCD or to induce the helical structure of STN-LCD. As the chiral agent, a commercially available product can be used. Examples thereof include cholesteryl nonanoate (CN), S-811, R-811, CB-15, and C-15 manufactured by Merck. It is known that the induced helical pitch becomes longer and shorter as the temperature rises, but one of these may be used alone or in combination of two or more, or both may be used in combination of one or more. good. For example, in the TN-LCD, STN-LCD, and TFT-LCD, the quotient d / p of the thickness d between the substrates and the induced spiral pitch p can be selected from the range of 0.001 to 24, but the range of 0.01 to 12 The range of 0.1 to 2 is more preferable, the range of 0.1 to 1.5 is still more preferable, the range of 0.1 to 1 is still more preferable, and the range of 0.1 to 0.8 is particularly preferable.

  The nematic liquid crystal composition is useful for TN-LCD, STN-LCD, OCB-LCD, polymer dispersion type liquid crystal display element, phase change type cholesteric liquid crystal display element, but is particularly useful for TN-LCD and STN-LCD. is there. Further, it can be used for a transmissive or reflective liquid crystal display element.

  In the TN liquid crystal display element of the present invention, the twist angle can be selected in the range of 80 ° to 130 °, preferably 85 ° to 110 °, depending on the purpose. In the STN liquid crystal display element of the present invention, the twist angle can be selected in the range of 180 ° to 270 ° depending on the purpose, and 220 ° to 260 ° is preferable.

  By using the liquid crystal composition of the present invention, in a time-division drive display of 1/32 to 1/400 duty, more preferably 1/60 to 1/250 duty, excellent high-speed response and low ion density As a result, a change in drive voltage due to the frequency distribution of each pixel can be suppressed, thereby reducing display unevenness and providing a high-contrast liquid crystal display element that is improved with respect to an increase in the amount of information and color display.

EXAMPLES Hereinafter, although an Example is given and this invention is further explained in full detail, this invention is not limited to these Examples. Further, “%” in the compositions of the following Examples and Comparative Examples means “% by mass”.
In the examples, the measured characteristics are as follows.
T _NI : Nematic phase-isotropic liquid phase transition temperature (° C)
Δε: Dielectric anisotropy (25 ° C)
Δn: Refractive index anisotropy (25 ° C)
η: Viscosity (mPa · s) (20 ° C)
The STN-LCD display element was created as follows. A chiral substance “S-811” (manufactured by Merck & Co., Inc.) was added to the nematic liquid crystal composition to prepare a mixed liquid crystal, which was injected into a STN-LCD display cell having a twist angle of 240 degrees. The chiral material was adjusted so that the natural spiral pitch P of the mixed liquid crystal by adding the chiral material was 10.0 μm, and the display cell thickness d was 5.0 μm.

Vth (STN): Threshold voltage (V)
Vsat (STN): Saturation voltage (V)
γ: Steepness Vsat (STN) / Vth (STN)
τ: Responsiveness (msec)
ΔV / Δf (Vth [5000Hz] −Vth [64Hz]) / Vth [64Hz] × 100%
ID: When measured by applying a 10V, 0.03Hz triangular waveform at 25 ° C
Liquid crystal cell ion density (nC / cm ² )

The following abbreviations are used in compound descriptions.
-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} -CH = CH- (CH 2) m-1)
ndm-: C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-1-
-Od (m) n: -O ( C n H 2n + 1 -CH = CH- (CH 2) m-2)
d (m) nO-: C _n H _{2n + 1} -CH = CH- (CH ₂ ) _m-2 O-
Linking group
-VO-: -COO- -T-: -C≡C-
-2-: -CH ₂ CH ₂ --Z-: -CH = NN = CH-
Substituent
-CN: -C≡N -F: -F
ring
Ph: 1,4-phenylene group Ph1: 3-fluoro-1,4-phenylene group
Ph2: 3,5-difluoro-1,4-phenylene group
Ma: Pyrimidine-2,5-diyl group Cy: 1,4-cyclohexylene group
Moreover, the compound which has the following structures as a compound suitable as a 4th component was used in the Example. In the table, it is expressed as the fourth component -A to G as follows.

The following compounds having a hydroxyl group not forming an intramolecular hydrogen bond were used as compounds which are similar to compounds suitable as the fourth component but cannot be used. In the table, it is expressed as non-fourth component -A to C as follows.

In non-fourth components -A and B, the hydroxyl group at the 2-position of the aromatic ring both forms a hydrogen bond with the carbonyl group at the 1-position, but the hydroxyl group at the 4-position cannot form an intramolecular hydrogen bond. . In the fourth component-C, the hydroxyl group at the 2-position of the aromatic ring can form a hydrogen bond with the nitrogen atom of the triazole ring, but the hydroxyl group at the 4-position cannot form an intramolecular hydrogen bond. It is.

The liquid crystal composition of Example 1 has improved viscosity, ion density in the STN display element, and ΔV / Δf while maintaining a high Δn as compared with Comparative Examples 2 and 3. Further, as compared with Comparative Examples 4 to 5, while maintaining a low viscosity, it has a higher Δn, and the viscosity and the ion density in the STN display element, ΔV / Δf are improved. Furthermore, the ion density and ΔV / Δf in the STN display element are improved as compared with Comparative Example 1 that does not contain the fourth component.

In Comparative Examples 6 to 8 prepared by adding a compound having a structure similar to the fourth component but not defined as the fourth component in the present invention to Comparative Example 1, all of them in the SNT display device The ion density and ΔV / Δf are greatly deteriorated.

It can be seen that Examples 2 to 7 using the fourth component B to G in the compound defined as the fourth component all have the same effect as compared to Example 1.

It can be seen that Examples 8 to 10 using the compound defined by Third Component-1 as the third component also have the same effect as Example 1.

In the comparative example 9 of the first component and the third component and the comparative example 10 of the first component + the third component + the fourth component, the SNT display element has the same viscosity and Δn as compared with the first embodiment. It can be seen that the ion density and ΔV / Δf are greatly inferior.

It is a figure which shows (DELTA) n and viscosity of the liquid-crystal composition of this invention. It is a figure which shows the liquid crystal cell ion density and viscosity of the liquid-crystal composition of this invention. It is a figure which shows the liquid crystal cell response speed and (DELTA) V / (DELTA) f of the liquid-crystal composition of this invention.

Claims (13)

General formula (1) as the first component

(In the formula, R ₁ represents 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.)
Containing one or more compounds represented by 2-20% by mass,
General formula (2) as the second component

(In the formula, R ₂ represents an alkyl group having 1 to 8 carbon atoms.) 8 to 38% by mass of the compound represented by 1 to 8%, and the total content of the first component and the second component Is 10-40% by mass,
General formula (3) as the third component

(In the formula, R ₃ and R ₄ 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. Z ₁ represents —CH ₂ CH ₂ —, —CH═CH—, —COO—, —OCO—, or a single bond, and Y _{1 to} Y ₈ each independently represent a hydrogen atom, a fluorine atom, or methyl. A group, and A represents a 1,4-phenylene group or a 1,4-cyclohexylene group).
As a fourth component, 0.001 to 5% by mass of an ultraviolet absorber having a maximum absorption wavelength at 250 to 400 nm of 290 nm or more, and when the ultraviolet absorber has a hydroxyl group in the molecular structure, all the hydroxyl groups are intramolecular hydrogen A nematic liquid crystal composition characterized in that a bond is formed. UV absorber is the general formula (4)

(In the formula, R ₅ represents a single bond or an alkylene group having 1 to 20 carbon atoms, and the carbon atom in the alkylene group may be substituted by halogen, and one or two or more in the alkylene group) -CH ₂ -may be substituted by -O-, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O- as those in which oxygen atoms are not directly bonded to each other. In the alkylene group, one or more of —CH ₂ CH ₂ — may be substituted by —CH═CH—, and L ₁ and L ₂ are each independently a hydrogen atom, a hydroxyl group, When an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 1 to 20 carbon atoms is represented, but at least one of L ₁ and L ₂ is a hydroxyl group, and the wavy line represents a connecting portion of the partial structure, but is not connected Represents a hydrogen atom)), a compound having a partial structure represented by
Formula (5)

(The wavy line represents the connecting part of the partial structure, but represents a hydrogen atom when not connected), a compound having a partial structure represented by:
General formula (6)

(Wherein L ₃ and L ₄ each independently represent a hydrogen atom, a hydroxyl group, an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 1 to 20 carbon atoms, but at least one of L ₃ and L ₄ Is a hydroxyl group, and the wavy line represents a connecting portion of the partial structure, but when not connected, represents a hydrogen atom.) And a compound having a partial structure represented by formula (7)

2. The nematic liquid crystal composition according to claim 1, wherein the wavy line represents a connecting portion of the partial structure, but represents a hydrogen atom when not connected, and is selected from the group consisting of compounds having a partial structure. . The liquid crystal composition according to claim 1 or 2, wherein in the general formula (1), R ₁ represents a linear alkyl group having 1 to 8 carbon atoms or a linear alkenyl group having 2 to 8 carbon atoms. In the general formula (3), A represents a 1,4-cyclohexylene group, Y _{1 to} Y ₈ represent a hydrogen atom, Z ₁ represents a single bond, or A represents a 1,4-phenylene group. 4. The liquid crystal composition according to claim ₁ , wherein at least one of Y _{1 to} Y ₈ represents a fluorine atom, and Z ₁ represents a single bond. General formula (8)

(In the formula, R ₅ represents a single bond or an alkylene group having 1 to 20 carbon atoms, and the carbon atom in the alkylene group may be substituted by halogen, and one or two or more in the alkylene group) -CH ₂ -may be substituted by -O-, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O- as those in which oxygen atoms are not directly bonded to each other. In the alkylene group, one or more of —CH ₂ CH ₂ — may be substituted by —CH═CH—, and L _{5 to} L ₉ are each independently a hydrogen atom, a hydroxyl group, , A fluorine atom, a chlorine atom, an alkyl group having 1 to 20 carbon atoms which may be substituted by at least one halogen, or an alkenyl group having 2 to 20 carbon atoms which may be substituted by at least one halogen, and these 1 or 2 or more of —CH ₂ — present in the group of —O—, in which oxygen atoms are not directly bonded to each other, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O- may be substituted, but at least one of L ₅ and L ₆ is a hydroxyl group, and L ₁₀ ˜L ₁₃ may each independently be substituted with a hydrogen atom, a fluorine atom, a chlorine atom, an alkyl group having 1 to 20 carbon atoms which may be substituted with at least one halogen, or at least one halogen. Represents an alkenyl group having 2 to 20 carbon atoms, and one or two or more —CH ₂ — present in these groups are each independently —O—, —N where oxygen atoms are not directly bonded to each other. 3. A nematic liquid crystal composition according to claim 2, comprising an ultraviolet absorber represented by the formula:-, -S-, -CO-, -COO-, -OCO- or -OCO-O-. . General formula (9)

(Wherein R ₆ is an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms substituted by at least one halogen, an alkenyl group having 2 to 20 carbon atoms, or a carbon substituted by at least one halogen. Represents an alkenyl group having a number of 2 to 20, and one or more of —CH ₂ — present in these groups are each independently —O—, —N—, wherein oxygen atoms are not directly bonded to each other. , -S-, -CO-, -COO-, -OCO- or -OCO-O-, C and D represent phenyl groups, each independently present in these groups at least One hydrogen atom may be substituted by an alkyl or alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, a fluorine atom, a chlorine atom, or -OCF ₃ ). The nematic liquid crystal composition according to claim 2 containing an agent. General formula (10)

(In the formula, L ₁₄ and L ₁₅ each independently represent a hydroxyl group or a hydrogen atom, but at least one is a hydroxyl group, and L _{16 to} L ₁₉ each independently represent —SO ₃ Na, —SO ₃ H Represents an alkyl group having 1 to 20 carbon atoms which may be substituted by at least one halogen, and an alkenyl group having 2 to 20 carbon atoms which may be substituted by at least one halogen, and is present in these groups 1 One or two or more CH ₂ groups are independently -O-, -N-, -S-, -CO-, -COO-, -OCO-, or -OCO, as oxygen atoms are not directly bonded to each other. The nematic liquid crystal composition according to claim 2, which comprises an ultraviolet absorber represented by the formula: General formula (11)

(Wherein a, b and c each independently represents an integer of 0 or 1, and L _{20 to} L ₂₈ are each independently substituted with a hydrogen atom, a fluorine atom, a chlorine atom, a hydroxyl group or at least one halogen. Represents an optionally substituted alkyl group having 1 to 20 carbon atoms, or an alkenyl group having 2 to 20 carbon atoms which may be substituted with at least one halogen, and one or two or more-present in these groups CH ₂ -is independently replaced by -O-, -N-, -S-, -CO-, -COO-, -OCO- or -OCO-O- as those oxygen atoms are not directly bonded to each other. 3. The nematic according to claim 2, further comprising an ultraviolet absorber represented by the formula: wherein at least one of L ₂₁ , L ₂₂ , L ₂₄ , L ₂₅ , L ₂₇ and L ₂₈ represents a hydroxyl group. Liquid crystal composition. General formula (12-a), General formula (12-b), General formula (12-c), General formula (12-d), General formula (12-e), General formula (12-f), General formula (12-g) or general formula (12-h)

Wherein R ₇ and R ₈ 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. Y _{9 to} Y ₁₂ each independently represents a hydrogen atom, a fluorine atom or a methyl group, and Z ₂ represents —CH ₂ CH ₂ —, —CH═CH—, —COO—, —OCO—, or a single atom. In general formulas (12-g) and (12-h), single bonds are excluded, Z ₃ represents —C≡C—, —COO— or —OCO—, and Z ₄ represents — The nematic liquid crystal composition according to any one of claims 1 to 8, which contains one or more compounds represented by COO- or -OCO-). The nematic liquid crystal composition according to claim 1, wherein the dielectric anisotropy (Δε) is in the range of 5 to 35. The nematic liquid crystal composition according to claim 1, wherein the refractive index anisotropy (Δn) is in the range of 0.10 to 0.26. The liquid crystal display element using the liquid-crystal composition in any one of Claims 1-11. The super twisted nematic (STN) liquid crystal display element according to claim 12, wherein the twist angle is in a range of 180 to 270 °.

Images