JP2006124544A - Nematic liquid crystal composition and liquid crystal display element using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal composition with improved light fastness in nematic liquid crystal composition with large absolute negative dielectric anisotropy. <P>SOLUTION: The nematic liquid crystal composition comprises ≥3% of one or two or more kind of liquid crystal compound having negative dielectric anisotropy with ≥5 of absolute value and a UV absorber, wherein the dielectric anisotropy is -2 to -8. The liquid crystal composition is useful as a liquid crystal composition for an active matrix, especially useful for as a constituting member of a VA (vertically oriented) type liquid crystal display element because the composition has a high voltage holding ratio and remarkably improved light fastness. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a nematic liquid crystal composition in which a decrease in voltage holding ratio due to light is significantly suppressed, and a liquid crystal display device using the same.

  Liquid crystal display elements are used in clocks, calculators, household electric appliances, measuring instruments, automotive panels, word processors, electronic notebooks, printers, computers, televisions, etc. TN (twisted nematic), STN (super twisted nematic), DS (dynamic light scattering), GH (guest / host), IPS (in-plane switching), OCB (optically compensated birefringence) ) Type, ECB (voltage controlled birefringence) type, VA (vertical alignment) type, FLC (ferroelectric liquid crystal), and the like. Also, as a drive system, a multiplex drive is generally used instead of a conventional static drive, and a simple matrix system, and recently an active matrix (AM) system driven by a TFT (thin film transistor), TFD (thin film diode), etc. has become mainstream. ing.

  In these display systems, active matrix systems such as IPS, OCB, and VA types need to use a liquid crystal composition that has a very high voltage holding ratio, unlike TN and STN types that are currently in general use. . Further, as a requirement from the viewpoint of reliability, there is a demand for a liquid crystal composition that is hardly affected by light and heat and can maintain a high retention rate.

  To date, there have been many reports that the reliability can be improved by adding an antioxidant, an ultraviolet absorber or the like to the liquid crystal composition. For example, by adding an antioxidant of 5% by mass or less, a liquid crystal composition having a wide nematic temperature range, excellent low-temperature stability and heat stability, and a high voltage holding ratio (see Patent Document 1). It is disclosed that it can be obtained, and there is also a description of benzotriazole. However, since the purpose is to improve the heat resistance, there is no description about a method for improving the light resistance and the effect thereof.

  Also disclosed is a liquid crystal display element (see Patent Document 2) that ensures extremely good light resistance by adding an additive having an absorption band in the ultraviolet wavelength region to the liquid crystal composition. There is also a description about triazole. However, since the main focus is on a liquid crystal composition that is optimal for the STN type, there is no description regarding the improvement in light resistance of the liquid crystal composition developed in the active matrix system. In particular, there is no suggestion for improving light resistance of a liquid crystal composition having a negative dielectric anisotropy which is significantly different from that of a general liquid crystal composition having a positive dielectric anisotropy. There is no description regarding the voltage holding ratio, which is the most important measurement item.

  In addition, there is a disclosure relating to a liquid crystal display element (see Patent Document 3) in which the light resistance of the liquid crystal is increased and the lifetime is extended by mixing an ultraviolet absorber in the liquid crystal to which the dichroic dye is added. However, there is no description regarding the light resistance improvement of the liquid crystal composition developed for the active matrix method, particularly the liquid crystal composition having a negative dielectric anisotropy, and there is also a description regarding the voltage holding ratio which is the most important measurement item in the reliability. Absent.

  Therefore, a method for improving the light resistance of a liquid crystal composition having a negative dielectric anisotropy suitable for an active matrix system having a high voltage holding ratio has been demanded.

JP 2002-256267 A (Claims) JP-A-8-176549 (page 5) JP-A-57-85879

  The problem to be solved by the present invention is to provide a liquid crystal composition having improved light resistance in a nematic liquid crystal composition since the dielectric anisotropy having a large absolute value is negative.

  As a result of intensive studies to solve the above problems, the present invention contains at least one 3% or more of a liquid crystal compound having a negative dielectric anisotropy containing an ultraviolet absorber and having an absolute value of 5 or more, A nematic liquid crystal composition having a dielectric anisotropy of −2 to −8 and a liquid crystal display device using the liquid crystal composition are provided.

  The liquid crystal composition comprising a liquid crystal compound having a negative dielectric anisotropy having an absolute value of 5 or more and an ultraviolet absorber according to the present invention has a high voltage holding ratio and significantly improves light resistance. That is, a decrease in the voltage holding ratio after ultraviolet irradiation could be greatly suppressed. Since the liquid crystal display element using this has improved light resistance as compared with the prior art, it has a longer lifetime.

  In the liquid crystal composition of the present invention, as the ultraviolet absorber, the general formula (IV)

(Wherein R ¹³ represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, and at least one CH ₂ present in these groups may be substituted with O) Rings M and N each independently represent a phenyl group, and each of these groups independently represents at least one hydrogen atom present in an alkyl group or alkoxyl group having 1 to 5 carbon atoms, or 2 to 5 carbon atoms. An alkenyl group, a fluorine atom, a chlorine atom, -CF ₃ , -OCF ₃ , -OH or -NO ₂ ), or a cyanoacrylate derivative represented by the general formula (V)

(Wherein Y ¹ represents a hydrogen atom, an alkyl group or alkoxyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, a fluorine atom, a chlorine atom, —CF ₃ or —OCF ₃ , R ²⁶ and R ²⁷ is preferably independently a benzotriazole derivative represented by a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxyl group, and an alkenyl group having 2 to 10 carbon atoms. When comparing IV) and general formula (V), general formula (IV) is more preferred.

  The compound represented by the general formula (IV) is more preferably a compound represented by the general formula (IV-a).

R ²⁵ in the formula is more preferably an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, and an alkenyl group having 2 to 5 carbon atoms, and X ¹⁵ and X ¹⁶ are each independently a hydrogen atom, An alkyl group or an alkoxyl group, an alkenyl group having 2 to 5 carbon atoms, a fluorine atom, a chlorine atom, —CF ₃ , or —OCF ₃ may be substituted.

  The compound represented by the general formula (V) is more preferably a compound represented by the general formula (V-a).

In the formula, R ²⁸ and R ²⁹ each independently represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, and an alkenyl group having 2 to 5 carbon atoms.
Increasing the content of a compound selected from the group represented by the general formula (IV) or general formula (V) can improve the light resistance more, but decreases the Tni of the liquid crystal composition. Is more preferably in the range of 0.005 to 0.8% by mass, and particularly preferably in the range of 0.01 to 0.5% by mass.

  General formula (I-a) and general formula (I-b) as liquid crystal compounds having negative dielectric anisotropy whose absolute value is 5 or more

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and exists in these groups) At least one CH ₂ may be substituted with O, and at least one hydrogen atom may be substituted with a fluorine atom, and A, B, C and D are each independently 1,4-phenylene. Group, trans-1,4-cyclohexylene group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group And at least one hydrogen atom present in these groups may be substituted with a fluorine atom or a methyl group, and Z ¹ , Z ² , Z ³ and Z ⁴ are each independently —CH ₂ CH ₂ — , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO-, -OCO- or a single bond, k, l, m and n each independently represents 0 to 2. X ¹ , X ² , X ³ , X ⁴ , X ⁵ And X ⁶ each independently represents a fluorine atom or a chlorine atom.), But more preferred examples include those represented by general formula (IA) to general formula (IL). There are compounds represented.

In the formula, R ¹⁴ is preferably an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, or an alkenyl group having 2 to 5 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms. R ¹⁵ is preferably an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, and an alkenyl group having 2 to 5 carbon atoms, more preferably an alkoxyl group having 1 to 5 carbon atoms. Z ¹³ represents -CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-,- CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO -, -OCO- or a single bond is preferred, but -CH ₂ O-, -CH ₂ CH ₂ O- or -CF ₂ O- is more preferred. Z ¹⁴ is -CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-,- CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-( CH ₂ ) ₃ O—, —O (CH ₂ ) ₃ —, —C≡C—, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO— or a single bond are preferred, It is more preferably —CH ₂ CH ₂ —, —CH═CH—, —COO—, —OCO— or a single bond.

  A liquid crystal compound is arbitrarily selected from the group represented by the general formula (I-A) to the general formula (I-L), and its specific structure and measurement result of dielectric constant are shown. Note that delta-ep represents the dielectric anisotropy Δε at 25 ° C. The value is a base liquid crystal whose dielectric anisotropy at 25 ° C is about 0, and 10 mass of any liquid crystal compound is prepared. By adding%, it was determined as an extrapolated value.

The content of the compound represented by the general formula (Ia) or the general formula (Ib) is preferably in the range of 3 to 60% by mass, more preferably in the range of 3 to 50% by mass. To 40% by mass is particularly preferred.

  General formula (II-a) and general formula (II-b) as liquid crystal compounds having negative dielectric anisotropy whose absolute value is 5 or more

(Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and is present in these groups. At least one CH ₂ may be substituted with O, and at least one hydrogen atom may be substituted with a fluorine atom, and E, F, G and H are each independently 1,4-phenylene. Group, trans-1,4-cyclohexylene group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group And at least one hydrogen atom present in these groups may be substituted with a fluorine atom or a methyl group, Z ⁵ , Z ⁶ , Z ⁷ and Z ⁸ are each independently —CH ₂ CH ₂ — , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO-, -OCO- or a single bond, o, p, q and r each independently represent 0 to 2. X ⁷ , X ⁸ , X ⁹ and X ¹⁰ each independently It is preferable to contain a compound selected from the group represented by general formula (II-A) to general formula (II-H). There are compounds that are

In the formula, R ¹⁶ is preferably an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, or an alkenyl group having 2 to 5 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms. R ¹⁷ is preferably an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, and an alkenyl group having 2 to 5 carbon atoms, more preferably an alkoxyl group having 1 to 5 carbon atoms. R ¹⁸ is preferably an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, or an alkenyl group having 2 to 5 carbon atoms, more preferably an alkyl group having 1 to 5 carbon atoms. Z ¹⁵ and Z ¹⁸ are each independently -CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, Although it is preferably —OCF ₂ —, —COO—, —OCO— or a single bond, it is more preferably —CH ₂ O—, —CH ₂ CH ₂ O— or —CF ₂ O—. Z ¹⁶ is -CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-,- CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO -, -OCO- or a single bond is preferred, but -CH ₂ CH _2- , -CH = CH-, -COO-, -OCO- or a single bond is more preferred. Z ¹⁷ is -CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-,- CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO -, -OCO- or a single bond is preferred, but -OCH _2- , -OCH ₂ CH ₂ -or -OCF _2- is more preferred.

  A liquid crystal compound is arbitrarily selected from the group represented by the general formula (II-A) to the general formula (II-H), and its specific structure and measurement result of dielectric constant are shown. Note that delta-ep represents the dielectric anisotropy Δε at 25 ° C.

The content of the compound represented by the general formula (II-a) or the general formula (II-b) is preferably in the range of 3 to 80% by mass, but more preferably in the range of 3 to 70% by mass. A range of 10 to 60% by mass is particularly preferable.

  As a liquid crystal compound having negative dielectric anisotropy having an absolute value of 5 or more, general formula (III-a) and general formula (III-b)

(Wherein R ⁹ , R ¹⁰ , R ¹¹ and R ¹² each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, and exists in these groups. At least one CH ₂ may be substituted with O, and at least one hydrogen atom may be substituted with a fluorine atom, ring I, ring J, ring K and ring L are each independently 1 , 4-phenylene group, trans-1,4-cyclohexylene group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6 -Represents a diyl group, and at least one hydrogen atom present in these groups may be substituted with a fluorine atom or a methyl group, Z ⁹ , Z ¹⁰ , Z ¹¹ and Z ¹² are each independently —CH 2. ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ C H _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡ C—, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO— or a single bond, s, t, u and v each independently represents 0 to 2. X ¹¹ , X ¹² , X ¹³ and X ¹⁴ each independently represents a fluorine atom or a chlorine atom), but preferably contains a compound selected from the group represented by formula (III-a) or (III- More preferred examples of b) include compounds represented by general formula (III-A) to general formula (III-L).

In the formula, each of R ¹⁹ and R ²⁰ is preferably independently an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, or an alkenyl group having 2 to 5 carbon atoms, but is an alkyl group having 1 to 5 carbon atoms. It is more preferable. R ²¹ is preferably an alkyl group having 1 to 5 carbon atoms or an alkoxyl group, and an alkenyl group having 2 to 5 carbon atoms, more preferably an alkoxyl group having 1 to 5 carbon atoms. Z ¹⁹ is -CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-,- CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO -, -OCO- or a single bond is preferred, but -CH ₂ O-, -CH ₂ CH ₂ O- or -CF ₂ O- is more preferred. Z ²⁰ and Z ²¹ are each independently -CH ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO-, -OCO- or a single bond is preferable, but -CH ₂ CH _2- , -CH = CH-, -COO-, -OCO- or a single bond is more preferable. preferable.

  A liquid crystal compound is arbitrarily selected from the group represented by the general formula (III-A) to the general formula (II-L), and its specific structure and measurement result of dielectric constant are shown. Note that delta-ep represents the dielectric anisotropy Δε at 25 ° C.

  In addition, the content of the compound represented by the general formula (III-a) or the general formula (III-b) is more preferably in the range of 3 to 50% by mass, and in the range of 3 to 40% by mass. Is particularly preferred.

  Furthermore, the liquid crystal composition of the present invention may use a general liquid crystal compound having dielectric anisotropy having an absolute value of 5 or less as shown below.

In the formula, each of R ²² and R ²³ is preferably independently an alkyl group or alkoxyl group having 1 to 5 carbon atoms, or an alkenyl group having 2 to 5 carbon atoms. R ²⁴ is preferably an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms.
Furthermore, the nematic liquid crystal composition of the present invention may contain ordinary nematic liquid crystal, smectic liquid crystal, cholesteric liquid crystal and the like in addition to the above-mentioned compounds.
The liquid crystal composition of the present invention is preferably a combination of liquid crystal compounds as described below.

  In the liquid crystal composition of the present invention, the content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 3 to 50% by mass, the content of the general formula (IV) and the general formula (V) is More preferably from 0.005 to 0.8% by mass, the content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 3 to 40% by mass, the general formula (IV) or the general formula (V) It is particularly preferable that the content of the compound represented by the formula is 0.01 to 0.5% by mass.

In the liquid crystal composition of the present invention, the content of the compound group represented by the general formula (II-a) and the general formula (II-b) is 3 to 70% by mass, the general formula (IV) or the general formula (V) The content of the compound represented by formula (II) is more preferably 0.005 to 0.8% by mass, and the content of the compound group represented by general formula (II-a) and general formula (II-b) is 10 to 60% by mass. %, The content of the compound represented by the general formula (IV) or the general formula (V) is particularly preferably 0.01 to 0.5% by mass.
In the liquid crystal composition of the present invention, the content of the compound group represented by the general formula (III-a) and the general formula (III-b) is 3 to 50% by mass, the general formula (IV) or the general formula (V) The content of the compound represented by the formula is more preferably 0.005 to 0.8% by mass, and the content of the compound group represented by the general formula (III-a) and the general formula (III-b) is 3 to 40% by mass. %, The content of the compound represented by the general formula (IV) or the general formula (V) is particularly preferably 0.01 to 0.5% by mass.

  In the liquid crystal composition of the present invention, the content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 3 to 50% by mass, the general formula (II-a) and the general formula (II-b) It is more preferable that the content of the compound group represented by 3 to 70 mass%, the content of the compound represented by the general formula (IV) or the general formula (V) is 0.005 to 0.8 mass%, The content of the compound group represented by (Ia) and general formula (Ib) is 3 to 40% by mass, and the content of the compound group represented by general formula (II-a) and general formula (II-b) is It is particularly preferable that the content of the compound represented by the general formula (IV) or the general formula (V) is 10 to 60% by mass and 0.01 to 0.5% by mass.

  In the liquid crystal composition of the present invention, the content of the compound group represented by the general formula (II-a) and the general formula (II-b) is 3 to 70% by mass, the general formula (III-a) and the general formula ( More preferably, the content of the compound group represented by III-b) is 3 to 50% by mass, and the content of the compound represented by the general formula (IV) or the general formula (V) is 0.005 to 0.8% by mass. Preferably, the content of the compound group represented by the general formula (II-a) and the general formula (II-b) is 10 to 60% by mass, represented by the general formula (III-a) and the general formula (III-b). It is particularly preferable that the content of the compound group to be obtained is 3 to 40% by mass, and the content of the general formula (IV) and the general formula (V) is 0.01 to 0.5% by mass.

In the liquid crystal composition of the present invention, the content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 3 to 50% by mass, the general formula (III-a) and the general formula (III-b) It is more preferable that the content of the compound group represented by 3 to 50% by mass, the content of the compound represented by the general formula (IV) or the general formula (V) is 0.005 to 0.8% by mass, The content of the compound group represented by (Ia) and general formula (Ib) is 3 to 40% by mass, and the content of the compound group represented by general formula (III-a) and general formula (III-b) is It is particularly preferable that the content of the compound represented by 3 to 40% by mass and the general formula (IV) or the general formula (V) is 0.01 to 0.5% by mass.
In the liquid crystal composition of the present invention, the content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 3 to 50% by mass, the general formula (II-a) and the general formula (II-b) The content of the compound group represented by the formula is 3 to 70% by mass, the content of the compound group represented by the general formula (III-a) and the general formula (III-b) is 3 to 50% by mass, More preferably, the content of the compound represented by IV) or the general formula (V) is 0.005 to 0.8% by mass, and the content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 3 to 40% by mass, the content of the compound group represented by general formula (II-a) and general formula (II-b) is 10 to 60% by mass, general formula (III-a) and general formula (III- It is particularly preferable that the content of the compound group represented by b) is 3 to 40% by mass, and the content of general formula (IV) and / or general formula (V) is 0.01 to 0.5% by mass.
In the liquid crystal composition of the present invention, the nematic phase-isotropic liquid phase transition temperature (Tni) is more preferably in the range of 80 to 105 ° C., and particularly preferably in the range of 80 to 95 ° C. The smectic phase or solid phase-nematic phase transition temperature (Tsn) is preferably −20 ° C. or lower, more preferably −30 ° C. or lower. The dielectric anisotropy (Δε) at 25 ° C. is more preferably in the range of −2.5 to −6.5, and particularly preferably in the range of −3.0 to −5.0. The refractive index anisotropy (Δn) at 25 ° C. is more preferably in the range of 0.08 to 0.15, and particularly preferably in the range of 0.08 to 0.13.

  In addition, the voltage holding ratio VHR (INITIAL) of the nematic liquid crystal composition of the present invention is preferably 95% or more, more preferably 98% or more. Furthermore, the voltage holding ratio VHR (UV) after ultraviolet irradiation is preferably 90% or more, more preferably 95% or more.

The nematic liquid crystal composition of the present invention is particularly useful for a VA mode active matrix liquid crystal display device.

  EXAMPLES The present invention will be described in further detail with reference to examples below, but the present 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.

Tni: Nematic phase-isotropic liquid phase transition temperature (° C)
Tsn: Smectic phase or solid phase-nematic phase transition temperature (℃)
Δn: Refractive index anisotropy at 25 ° C Δε: Dielectric anisotropy at 25 ° C
VHR (INITIAL): Voltage holding ratio at 25 ° C before UV irradiation (%)
VHR (UV): Voltage holding ratio at 25 ° C after UV irradiation (%)
The measurement conditions for the voltage holding ratio are an applied voltage of 5 V, a frame time of 16.5 ms, and a pulse width of 60 μsec. FL15BL-360 manufactured by Mitsubishi Electric OSRAM Co., Ltd. was used as the ultraviolet irradiation lamp, and ultraviolet rays were irradiated to the VA mode cell (cell thickness 3.5 μm, alignment film RN-1517) into which liquid crystal was injected for 60 minutes.
Example 1
The liquid crystal composition described below was prepared.

この組成物99.9％に一般式（IV）で表される化合物である以下の化合物0.1％を加え物性値を測定した。

The following compound 0.1%, which is a compound represented by the general formula (IV), was added to 99.9% of this composition, and physical properties were measured.

The characteristics of Example 1 were Tni: 84 ° C., Tsn: −45 ° C., Δn: 0.124, Δε: -3.2, VHR (INITIAL): 99.1%, VHR (UV): 95.3.
Further, as Comparative Example, Comparative Example 1 containing no compound represented by the general formula (IV) was prepared.
(Comparative Example 1)

The characteristics of Comparative Example 1 were Tni: 85 ° C, Tsn: -45 ° C, Δn: 0.124, Δε: -3.2, VHR (INITIAL): 98.9%, VHR (UV): 70.2%.
It can be seen that Example 1 maintains a higher voltage holding ratio even after UV irradiation.
(Example 2)
The liquid crystal composition described below was prepared.

The following compound 0.5%, which is a compound represented by the general formula (IV), was added to 99.5% of this composition, and physical properties were measured.

The characteristics of Example 2 were Tni: 84 ° C., Tsn: −30 ° C., Δn: 0.075, Δε: -2.8, VHR (INITIAL): 99.0%, and VHR (UV): 95.7.
Moreover, the comparative example 2 which does not contain the compound represented by general formula (IV) as a comparative example was prepared.
(Comparative Example 2)

The characteristics of Comparative Example 2 were Tni: 85 ° C., Tsn: −30 ° C., Δn: 0.075, Δε: −2.8, VHR (INITIAL): 99.0%, VHR (UV): 68.4%.
(Example 3)
The liquid crystal composition described below was prepared.

The following compound 0.1%, which is a compound represented by the general formula (V), was added to 99.9% of this composition, and physical properties were measured.

The characteristics of Example 3 were Tni: 90 ° C., Tsn: −30 ° C., Δn: 0.092, Δε: -3.2, VHR (INITIAL): 98.9%, and VHR (UV): 93.7.
Moreover, the comparative example 3 which does not contain the compound represented by general formula (V) as a comparative example was prepared.
(Comparative Example 3)

The characteristics of Comparative Example 3 were Tni: 91 ° C, Tsn: -30 ° C, Δn: 0.092, Δε: -3.2, VHR (INITIAL): 99.0%, VHR (UV): 73.4%.
Example 4
The liquid crystal composition described below was prepared.

The following compound 0.01%, which is a compound represented by the general formula (IV), was added to 99.99% of this composition, and physical properties were measured.

The characteristics of Example 4 were Tni: 85 ° C., Tsn: −36 ° C., Δn: 0.085, Δε: -2.5, VHR (INITIAL): 98.9%, VHR (UV): 96.7.
Moreover, the comparative example 4 which does not contain the compound represented by general formula (IV) as a comparative example was prepared.
(Comparative Example 4)

The characteristics of Comparative Example 4 were Tni: 85 ° C., Tsn: −36 ° C., Δn: 0.085, Δε: -2.5, VHR (INITIAL): 99.1%, VHR (UV): 74.4%.

Claims (18)

It contains a UV absorber, contains at least 3% of a liquid crystal compound having negative dielectric anisotropy having an absolute value of 5 or more, and has a dielectric anisotropy of −2 to −8. A nematic liquid crystal composition. The nematic liquid crystal composition according to claim 1, wherein the ultraviolet absorber is a cyanoacrylate derivative and / or a benzotriazole derivative. As a liquid crystal compound having negative dielectric anisotropy having an absolute value of 5 or more, general formula (Ia) and general formula (Ib)

(Wherein R ¹ , R ² , R ³ and R ⁴ each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and exists in these groups) At least one CH ₂ may be substituted with O, and at least one hydrogen atom may be substituted with a fluorine atom, and A, B, C and D are each independently 1,4-phenylene. Group, trans-1,4-cyclohexylene group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group And at least one hydrogen atom present in these groups may be substituted with a fluorine atom or a methyl group, and Z ¹ , Z ² , Z ³ and Z ⁴ are each independently —CH ₂ CH ₂ — , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO-, -OCO- or a single bond, k, l, m and n each independently represents 0 to 2. X ¹ , X ² , X ³ , X ⁴ , X ⁵ And X ⁶ each independently represents a fluorine atom or a chlorine atom.) The nematic liquid crystal according to claim 1 or 2, comprising one or more compounds selected from the group represented by: Composition. As a liquid crystal compound having negative dielectric anisotropy having an absolute value of 5 or more, general formula (II-a) and general formula (II-b)

(Wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and is present in these groups. At least one CH ₂ may be substituted with O, and at least one hydrogen atom may be substituted with a fluorine atom, and E, F, G and H are each independently 1,4-phenylene. Group, trans-1,4-cyclohexylene group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6-diyl group And at least one hydrogen atom present in these groups may be substituted with a fluorine atom or a methyl group, Z ⁵ , Z ⁶ , Z ⁷ and Z ⁸ are each independently —CH ₂ CH ₂ — , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ CH _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡C-, -CF ₂ O-, -OCF _2- , -COO-, -OCO- or a single bond, o, p, q and r each independently represent 0 to 2. X ⁷ , X ⁸ , X ⁹ and X ¹⁰ each independently The nematic liquid crystal composition according to any one of claims 1 to 3, further comprising one or more compounds selected from the group represented by: As a liquid crystal compound having negative dielectric anisotropy having an absolute value of 5 or more, general formula (III-a) and general formula (III-b)

(Wherein R ⁹ , R ¹⁰ , R ¹¹ and R ¹² each independently represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, and exists in these groups. At least one CH ₂ may be substituted with O, and at least one hydrogen atom may be substituted with a fluorine atom, ring I, ring J, ring K and ring L are each independently 1 , 4-phenylene group, trans-1,4-cyclohexylene group, naphthalene-2,6-diyl group, decahydronaphthalene-2,6-diyl group or 1,2,3,4-tetrahydronaphthalene-2,6 -Represents a diyl group, and at least one hydrogen atom present in these groups may be substituted with a fluorine atom or a methyl group, Z ⁹ , Z ¹⁰ , Z ¹¹ and Z ¹² are each independently —CH 2. ₂ CH _2- , -CH = CH-, -CH (CH ₃ ) CH _2- , -CH ₂ CH (CH ₃ )-, -CH (CH ₃ ) CH (CH ₃ )-, -CF = CF-, -CF ₂ CF _2- , -CH ₂ O-, -OCH _2- , -CH ₂ CH ₂ O-, -OCH ₂ C H _2- , -OCH (CH ₃ )-, -CH (CH ₃ ) O-,-(CH ₂ ) ₄ -,-(CH ₂ ) ₃ O-, -O (CH ₂ ) _3- , -C≡ C—, —CF ₂ O—, —OCF ₂ —, —COO—, —OCO— or a single bond, s, t, u and v each independently represents 0 to 2. X ¹¹ , X ¹² , X ¹³ and X ¹⁴ each independently represents a fluorine atom or a chlorine atom.) The compound according to any one of claims 1 to 4, which contains one or more compounds selected from the group represented by: Nematic liquid crystal composition. As UV absorber, general formula (IV)

(Wherein R ¹³ represents an alkyl group or alkoxyl group having 1 to 10 carbon atoms, or an alkenyl group having 2 to 10 carbon atoms, and at least one CH ₂ present in these groups may be substituted with O) Rings M and N each independently represent a phenyl group, and each of these groups independently represents at least one hydrogen atom present in an alkyl group or alkoxyl group having 1 to 5 carbon atoms, or 2 to 5 carbon atoms. An alkenyl group, a fluorine atom, a chlorine atom, -CF ₃ , -OCF ₃ , -OH, or -NO ₂ ). To 5. The nematic liquid crystal composition according to any one of items 1 to 5. As UV absorber, general formula (V)

(Wherein Y ¹ represents a hydrogen atom, an alkyl group or alkoxyl group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, a fluorine atom, a chlorine atom, —CF ₃ or —OCF ₃ , R ²⁶ and R ²⁷ each independently represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms or an alkoxyl group, and an alkenyl group having 2 to 10 carbon atoms.) One or more benzotriazole derivatives represented by The nematic liquid crystal composition according to any one of claims 1 to 6, wherein: The content of the compound group represented by the general formula (Ia) and the general formula (Ib) is 3 to 60% by mass, and the content of the compound represented by the general formula (IV) or the general formula (V) is 0. The nematic liquid crystal composition according to any one of claims 1 to 7, which has a content of 0.001 to 1% by mass. The content of the compound group represented by the compound group represented by the general formula (II-a) and the general formula (II-b) is 3 to 80% by mass, and the general formula (IV) or the general formula (V) The nematic liquid crystal composition according to claim 1, wherein the content of the compound represented by the formula is from 0.001 to 1% by mass. The content of the compound group represented by the general formula (III-a) and the general formula (III-b) is 3 to 60% by mass, and the compound represented by the general formula (IV) or the general formula (V) The nematic liquid crystal composition according to any one of claims 1 to 7, wherein the content is 0.001 to 1% by mass. A compound represented by the general formula (II-a) and the general formula (II-b) having a content of 3 to 60% by mass from the group of compounds represented by the general formula (Ia) and the general formula (Ib). The content of the arabe from the group is 3 to 80% by mass, and the content of the compound represented by the general formula (IV) or the general formula (V) is from 0.001 to 1% by mass. The nematic liquid crystal composition according to any one of the above. The content of the compound group represented by general formula (II-a) and general formula (II-b) is 3 to 80% by mass, and in general formula (III-a) and general formula (III-b) The content of the compound group represented is 3 to 60% by mass, and the content of the compound represented by the general formula (IV) or the general formula (V) is 0.001 to 1% by mass. Item 8. The nematic liquid crystal composition according to any one of items 1 to 7. A compound represented by general formula (III-a) and general formula (III-b) having a content of 3 to 60% by mass from the group of compounds represented by general formula (Ia) and general formula (Ib) The content of the arabe from the group is 3 to 60% by mass, and the content of the compound represented by the general formula (IV) or the general formula (V) is from 0.001 to 1% by mass. The nematic liquid crystal composition according to any one of the above. A compound represented by the general formula (II-a) and the general formula (II-b) having a content of 3 to 60% by mass from the group of compounds represented by the general formula (Ia) and the general formula (Ib). The content of the group is 3 to 80% by mass, the content of the compound group represented by the general formula (III-a) and the general formula (III-b) is 3 to 60% by mass, and the general formula The nematic liquid crystal composition according to any one of claims 1 to 7, wherein the content of the compound represented by (IV) or the general formula (V) is from 0.001 to 1% by mass. The refractive index anisotropy Δn at 25 ° C is in the range of 0.06 to 0.22, and the nematic phase-isotropic liquid phase transition temperature Tni is in the range of 70 to 120 ° C. A nematic liquid crystal composition according to claim 1. A liquid crystal display element using the nematic liquid crystal composition according to claim 1. An active matrix driven liquid crystal display device using the nematic liquid crystal composition according to claim 1. A VA mode liquid crystal display element using the nematic liquid crystal composition according to claim 1.