CN111826169A

CN111826169A - Liquid crystal composition, use thereof, and liquid crystal display element

Info

Publication number: CN111826169A
Application number: CN201911180726.7A
Authority: CN
Inventors: 斋藤将之; 御供田大地
Original assignee: JNC Corp; JNC Petrochemical Corp
Current assignee: JNC Corp; JNC Petrochemical Corp
Priority date: 2019-04-22
Filing date: 2019-11-27
Publication date: 2020-10-27
Anticipated expiration: 2039-11-27
Also published as: JP7331686B2; JP2020176256A; CN111826169B; TW202104556A; TWI835934B

Abstract

The present invention provides a liquid crystal composition which satisfies at least one of the characteristics of high upper limit temperature, low lower limit temperature, low viscosity, appropriate optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to light and high stability to heat, or has an appropriate balance between at least two of the characteristics, and a use thereof, and a liquid crystal display element. The liquid crystal composition of the present invention contains a specific compound having a high upper limit temperature as the component a, and may contain a specific compound having a large negative dielectric anisotropy as the component B, a specific compound having a small viscosity as the component C, or a specific compound having a polymerizable group as the additive X.

Description

Liquid crystal composition, use thereof, and liquid crystal display element

Technical Field

The present invention relates to a liquid crystal composition, use thereof, a liquid crystal display element containing the composition, and the like. In particular, the present invention relates to a liquid crystal composition having negative dielectric anisotropy, and a liquid crystal display device including the liquid crystal composition and having modes such as in-plane switching (IPS), Vertical Alignment (VA), Fringe Field Switching (FFS), and field-induced photoreaction alignment (FPA). And a polymer-stabilized alignment type liquid crystal display element.

Background

In the liquid crystal display device, the operation modes based on the liquid crystal molecules are classified as follows: phase Change (PC), Twisted Nematic (TN), Super Twisted Nematic (STN), Electrically Controlled Birefringence (ECB), Optically Compensated Bend (OCB), in-plane switching (IPS), Vertical Alignment (VA), Fringe Field Switching (FFS), field-induced photo-reactive alignment (FPA), and the like. The driving methods of the elements are classified into Passive Matrix (PM) and Active Matrix (AM). The PM is classified into a static type (static), a multiplexing type (multiplex), etc., and the AM is classified into a Thin Film Transistor (TFT), a Metal Insulator Metal (MIM), etc. TFTs are classified into amorphous silicon (amorphous silicon) and polycrystalline silicon (polysilicon). The latter is classified into a high temperature type and a low temperature type according to the manufacturing process. The light sources are classified into a reflection type using natural light, a transmission type using a backlight, and a semi-transmission type using both natural light and backlight.

The liquid crystal display element contains a liquid crystal composition having a nematic phase. The composition has suitable properties. By improving the characteristics of the composition, an AM element having good characteristics can be obtained. The correlation between these properties is summarized in table 1 below. The properties of the composition are further illustrated based on commercially available AM elements. The temperature range of the nematic phase is associated with the temperature range in which the element can be used. The upper limit temperature of the nematic phase is preferably about 70 ℃ or higher, and the lower limit temperature of the nematic phase is preferably about-10 ℃ or lower. The viscosity of the composition correlates to the response time of the element. In order to display a moving image as an element, the response time is preferably short. Ideally shorter than 1 millisecond of response time. Therefore, it is preferable that the viscosity of the composition is small. More preferably, the viscosity at low temperature is small.

The optical anisotropy of the composition correlates with the contrast of the element. Depending on the mode of the element, a large optical anisotropy or a small optical anisotropy, i.e., an appropriate optical anisotropy, is required. The product (Δ n × d) of the optical anisotropy (Δ n) of the composition and the cell gap (d) of the element is designed to maximize the contrast. The value of the appropriate product depends on the type of operation mode. The value is in the range of about 0.30 μm to about 0.40 μm in a VA mode element, and in the range of about 0.20 μm to about 0.30 μm in an IPS mode or FFS mode element. In these cases, a composition having a large optical anisotropy is preferable for an element having a small cell gap. The large dielectric anisotropy of the composition contributes to a low threshold voltage, small power consumption, and large contrast of the element. Therefore, a large dielectric anisotropy is preferable. The large specific resistance of the composition contributes to a large voltage holding ratio and a large contrast ratio of the element. Therefore, a composition having a large specific resistance in the initial stage is preferable. Preferred are compositions which have a large specific resistance after a long period of use. The stability of the composition to light or heat is correlated to the lifetime of the element. When the stability is high, the life of the element is long. Such characteristics are preferable for AM elements used in liquid crystal monitors, liquid crystal televisions, and the like.

In a general-purpose liquid crystal display device, the vertical alignment of liquid crystal molecules can be achieved by a specific polyimide alignment film. In a liquid crystal display element of a Polymer Sustained Alignment (PSA) type, a polymer is combined with an alignment film. First, a composition to which a small amount of a polymerizable compound is added is injected into an element. Next, the composition was irradiated with ultraviolet rays while applying a voltage between the substrates of the element. The polymerizable compound is polymerized to form a network structure of the polymer in the composition. In the composition, the orientation of the liquid crystal molecules can be controlled by the polymer, so that the response time of the element is shortened, and the afterimage of the image is improved. Such effects of the polymer can be expected in devices having modes such as TN, ECB, OCB, IPS, VA, FFS, and FPA.

A composition having positive dielectric anisotropy is used for an AM element having a TN mode. A composition having negative dielectric anisotropy is used for an AM element having a VA mode. A composition having positive or negative dielectric anisotropy is used for an AM element having an IPS mode or an FFS mode. A composition having positive or negative dielectric anisotropy is used in an AM element of a Polymer Sustained Alignment (PSA) type.

[ Prior art documents ]

[ patent document ]

[ patent document 1] Japanese patent laid-open No. Sho 58-194822

[ patent document 2] International publication No. 2012-043387

[ patent document 3] Japanese patent laid-open No. Hei 8-302353

Disclosure of Invention

[ problems to be solved by the invention ]

The invention provides a liquid crystal composition which fully satisfies at least one of the characteristics of high upper limit temperature of a nematic phase, low lower limit temperature of the nematic phase, low viscosity, appropriate optical anisotropy, large negative dielectric anisotropy, large specific resistance, high stability to light and high stability to heat. Another object is to provide a liquid crystal composition having an appropriate balance between at least two of these characteristics. Another object is to provide a liquid crystal display element containing such a composition. It is still another object to provide an AM device having characteristics such as a short response time, a high voltage holding ratio, a low threshold voltage, a high contrast ratio, and a long lifetime.

[ means for solving problems ]

The present invention relates to a liquid crystal composition containing at least one compound selected from compounds represented by formula (1) as component a and having negative dielectric anisotropy, and a liquid crystal display element containing the same.

In the formula (1), R¹And R²Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine; z¹、Z²And Z³Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy.

[ Effect of the invention ]

An advantage of the present invention is to provide a liquid crystal composition that sufficiently satisfies at least one of characteristics such as a high upper limit temperature of a nematic phase, a low lower limit temperature of the nematic phase, a small viscosity, an appropriate optical anisotropy, a large negative dielectric anisotropy, a large specific resistance, a high stability to light, and a high stability to heat. Another advantage is to provide a liquid crystal composition having an appropriate balance between at least two of these characteristics. Another advantage is to provide a liquid crystal display element containing such a composition. Still another advantage is to provide an AM device having characteristics such as a short response time, a large voltage holding ratio, a low threshold voltage, a large contrast ratio, and a long lifetime.

Drawings

Is free of

Detailed Description

The usage of the terms in the present specification is as follows. The terms "liquid crystal composition" and "liquid crystal display element" may be abbreviated as "composition" and "element", respectively. The term "liquid crystal display element" is a generic term for liquid crystal display panels and liquid crystal display modules. The "liquid crystal compound" is a general term for compounds having a liquid crystal phase such as a nematic phase or a smectic phase (smectic phase), and compounds which do not have a liquid crystal phase but are mixed in a composition for the purpose of adjusting characteristics such as a temperature range, viscosity, and dielectric anisotropy of a nematic phase. The compound has a six-membered ring such as 1, 4-cyclohexylene or 1, 4-phenylene, and the molecules (liquid crystal molecules) thereof are rod-like (rod like). The "polymerizable compound" is a compound added for the purpose of forming a polymer in the composition. The liquid crystalline compound having an alkenyl group is not classified into a polymerizable compound in terms of its meaning.

The liquid crystal composition is prepared by mixing a plurality of liquid crystalline compounds. An additive such as an optically active compound or a polymerizable compound is added to the liquid crystal composition as needed. Even in the case where an additive is added, the proportion of the liquid crystalline compound is represented by a mass percentage (mass%) based on the mass of the liquid crystal composition containing no additive. The proportion of the additive is represented by mass percentage (mass%) based on the mass of the liquid crystal composition containing no additive. That is, the ratio of the liquid crystalline compound or the additive is calculated based on the total mass of the liquid crystalline compound. Parts per million (ppm) by mass are sometimes used. The proportions of the polymerization initiator and the polymerization inhibitor are exceptionally represented based on the mass of the polymerizable compound.

The "upper limit temperature of the nematic phase" is sometimes abbreviated as "upper limit temperature". The "lower limit temperature of the nematic phase" is sometimes abbreviated as "lower limit temperature". The expression "increase in dielectric anisotropy" means that the value increases positively in a composition having positive dielectric anisotropy, and increases negatively in a composition having negative dielectric anisotropy. The "large voltage holding ratio" means that the device has a large voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature in the initial stage, and also has a large voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature after long-term use. The properties of the composition or the element are sometimes investigated by time-varying tests.

The compound (1z) is exemplified. In formula (1z), the symbols α and β surrounded by a hexagon correspond to ring α and ring β, respectively, and represent a six-membered ring, a condensed ring, and the like. Where the subscript 'x' is 2, there are two rings α. The two groups represented by the two rings a may be the same or may also be different. The rule applies to any two rings a where subscript 'x' is greater than 2. The rules also apply to other tokens such as the bonding base Z. The slash across one side of the loop β indicates that any hydrogen on the loop β may be substituted with a substituent (-Sp-P). The subscript 'y' indicates the number of substituents substituted. When subscript 'y' is 0, there is no such substitution. When the subscript 'y' is 2 or more, a plurality of substituents (-Sp-P) are present on the ring β. In that case, the rules "may be the same, or may also be different" also apply. Furthermore, the rules also apply to the use of the notation of Ra in a variety of compounds.

In formula (1z), for example, the expression "Ra and Rb are alkyl, alkoxy or alkenyl" means that Ra and Rb are independently selected from the group of alkyl, alkoxy and alkenyl. That is, the group represented by Ra and Rb may be the same or different.

At least one compound selected from the compounds represented by the formula (1z) may be abbreviated as "compound (1 z)". The "compound (1 z)" means one compound, a mixture of two compounds or a mixture of three or more compounds represented by the formula (1 z). The same applies to the compounds represented by the other formulae. The expression "at least one compound selected from the group consisting of the compounds represented by the formula (1z) and the formula (2 z)" means at least one compound selected from the group consisting of the compound (1z) and the compound (2 z).

The expression "at least one 'a'" means that the number of 'a's is arbitrary. The expression "at least one 'a' may be substituted with 'B' means that the position of 'a' is arbitrary when the number of 'a' is one, and the position thereof may be selected without limitation when the number of 'a' is two or more. Sometimes using "at least one-CH₂-may be substituted by-O-. In said case, -CH₂CH₂-CH₂Can pass through non-contiguous-CH₂-conversion to-O-CH by-O-substitution₂-O-. However, there is no contiguous-CH₂-substituted by-O-. The reason is that: in said substitution-O-CH is formed₂- (peroxides).

The alkyl group of the liquid crystalline compound is linear or branched and does not include a cyclic alkyl group. Straight chain alkyls are preferred over branched alkyls. The same applies to terminal groups such as alkoxy groups and alkenyl groups. Regarding the configuration of 1, 4-cyclohexylene group-related stereo-configuration, the trans (trans) configuration is preferred over the cis (cis) configuration in order to increase the upper limit temperature. Since 2-fluoro-1, 4-phenylene is asymmetric to the left and right, it is present in the left (L) and right (R) directions.

The same applies to divalent radicals such as tetrahydropyran-2, 5-diyl. The same applies to a bonding group (-COO-or-OCO-) such as carbonyloxy.

The present invention is as follows.

Item 1. a liquid crystal composition which contains at least one compound selected from the compounds represented by formula (1) as a component a and has negative dielectric anisotropy.

Item 2. the liquid crystal composition according to item 1, wherein the proportion of the component A is in the range of 3 to 30% by mass.

Item 3. the liquid crystal composition according to item 1 or item 2, which contains at least one compound selected from the compounds represented by formula (2) as the component B.

In the formula (2), R³And R⁴Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine; ring A and ring C are 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, or chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine; ring B is 2, 3-difluoro-1, 4-phenylene, 2-chloro-3-fluoro-1, 4-phenylene, 2, 3-difluoro-5-methyl-1, 4-phenylene, 3,4, 5-trifluoronaphthalene-2, 6-diyl, 7, 8-difluorochromane-2, 6-diyl, 3,4,5, 6-tetrafluorofluorene-2, 7-diyl, 4, 6-difluorodibenzofuran-3, 7-diyl, 4, 6-difluorodibenzothiophene-3, 7-diyl, or 1,1,6, 7-tetrafluoroindan-2, 5-diyl; z⁴And Z⁵Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; a is 0, 1,2 or 3, b is 0 or 1; and the sum of a and b is 3 or less.

Item 4. the liquid crystal composition according to any one of item 1 to item 3, which contains at least one compound selected from the group consisting of the compounds represented by formulae (2-1) to (2-35) as the component B.

In the formulae (2-1) to (2-35), R³And R⁴Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine.

Item 5. the liquid crystal composition according to item 3 or item 4, wherein the proportion of the component B is in the range of 10 to 90 mass%.

Item 6. the liquid crystal composition according to any one of item 1 to item 5, which contains at least one compound selected from the compounds represented by formula (3) as component C.

In the formula (3), R⁵And R⁶Is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine, or an alkenyl group having 2 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine; ring D and ring E are 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene or 2, 5-difluoro-1, 4-phenylene; z⁶Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; c is 1 or 2.

Item 7. the liquid crystal composition according to any one of items 1 to 6, which contains at least one compound selected from the compounds represented by formulae (3-1) to (3-9) as the component C.

In the formulae (3-1) to (3-9), R⁵And R⁶Is an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an alkenyl group having 2 to 12 carbon atoms, an alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine, or an alkenyl group having 2 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine.

Item 8. the liquid crystal composition of item 6 or item 7, wherein the proportion of the component C is in the range of 10 to 90 mass%.

Item 9. the liquid crystal composition according to any one of item 1 to item 8, which contains at least one compound selected from polymerizable compounds represented by formula (4) as an additive X.

In the formula (4), ring F and ring J are cyclohexyl, cyclohexenyl, phenyl, 1-naphthyl, 2-naphthyl, tetrahydropyran-2-yl, 1, 3-dioxan-2-yl, pyrimidin-2-yl or pyridin-2-yl, and in these rings, at least one hydrogen may be substituted with fluorine, chlorine, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine; ring G is 1, 4-cyclohexylene, 1, 4-cyclohexenylene, 1, 4-phenylene, naphthalene-1, 2-diyl, naphthalene-1, 3-diyl, naphthalene-1, 4-diyl, naphthalene-1, 5-diyl, naphthalene-1, 6-diyl, naphthalene-1, 7-diyl, naphthalene-1, 8-diyl, naphthalene-2, 3-diyl, naphthalene-2, 6-diyl, naphthalene-2, 7-diyl, tetrahydropyran-2, 5-diyl, 1, 3-dioxane-2, 5-diyl, pyrimidine-2, 5-diyl or pyridine-2, 5-diyl, and in these rings, at least one hydrogen may be substituted with fluorine, chlorine, an alkyl group having a carbon number of 1 to 12, an alkoxy group having a carbon number of 1 to 12, Or at least one hydrogen is substituted by a fluorine or chlorine substituted alkyl group of carbon number 1 to 12; z⁷And Z⁸Is a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -CO-, -COO-or-OCO-, at least one-CH₂CH₂-may be via-CH ═ CH-, -C (CH)₃)＝CH-、-CH＝C(CH₃) -or-C (CH)₃)＝C(CH₃) -substitution, of which at least one hydrogen may be substituted by fluorine or chlorine; p¹To P³Is a polymerizable group; sp¹To Sp³Is a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine; d is 0, 1 or 2; e. f and g are 0, 1,2, 3 or 4; and e, f andthe sum of g is 1 or more.

Item 10 the liquid crystal composition according to item 9, wherein, in formula (4), P¹To P³Is a group selected from the polymerizable groups represented by the formulae (P-1) to (P-5).

In the formulae (P-1) to (P-5), M¹To M³Hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

Item 11. the liquid crystal composition according to any one of item 1 to item 10, which contains at least one compound selected from polymerizable compounds represented by formulae (4-1) to (4-29) as an additive X.

In formulae (4-1) to (4-29), Sp¹To Sp³Is a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine; p⁴To P⁶Is a polymerizable group selected from the group represented by the formulae (P-1) to (P-3);

in the formulae (P-1) to (P-3), M¹To M³Is hydrogen, fluorine, alkyl with 1 to 5 carbon atoms, or at least oneAn alkyl group having 1 to 5 carbon atoms in which hydrogen is substituted with fluorine or chlorine.

Item 12. the liquid crystal composition of any one of items 9 to 11, wherein the proportion of the additive X is in the range of 0.03 to 10 mass%.

Item 13. a liquid crystal display element containing the liquid crystal composition according to any one of items 1 to 12.

Item 14. the liquid crystal display device of item 13, wherein the liquid crystal display device operates in an IPS mode, a VA mode, an FFS mode, or an FPA mode, and the liquid crystal display device is driven in an active matrix mode.

Item 15. a polymer-stabilized alignment type liquid crystal display element, which contains the liquid crystal composition according to any one of items 9 to 12, and in which a polymerizable compound is polymerized.

Item 16. use of a liquid crystal composition according to any one of items 1 to 12 in a liquid crystal display element.

Item 17. use of a liquid crystal composition according to any one of items 9 to 12 in a liquid crystal display element of a polymer stabilized alignment type.

The present invention also includes the following items. (a) The composition contains one compound, two compounds or three or more compounds selected from additives such as an optically active compound, an antioxidant, an ultraviolet absorber, a delustering agent, a pigment, an antifoaming agent, a polymerizable compound, a polymerization initiator and a polymerization inhibitor. (b) An AM element comprising the composition. (c) The composition further contains a polymerizable compound, and a polymer-stabilized oriented (PSA) AM element containing the composition. (d) An AM element of Polymer Stable Alignment (PSA) type, comprising the composition, wherein a polymerizable compound in the composition is polymerized. (e) An element comprising said composition and having a pattern of PC, TN, STN, ECB, OCB, IPS, VA, FFS or FPA. (f) A permeable element comprising the composition. (g) Use of said composition as a composition having a nematic phase. (h) Use of an optically active composition obtained by adding an optically active compound to the composition.

The composition of the present invention is illustrated in the following order. First, the composition is explained. Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or element will be described. Thirdly, combinations of the component compounds in the composition, preferable ratios and their basis are explained. Fourth, preferred embodiments of the component compounds will be described. Fifth, preferred component compounds are shown. Sixth, additives that can be added to the composition will be described. Seventh, a method for synthesizing the component compound will be explained. Finally, the use of the composition is illustrated.

First, the composition is explained. The composition contains a plurality of liquid crystalline compounds. The composition may also contain additives. The additive is an optically active compound, an antioxidant, an ultraviolet absorber, a matting agent, a coloring matter, an antifoaming agent, a polymerizable compound, a polymerization initiator, a polymerization inhibitor, a polar compound, or the like. From the viewpoint of the liquid crystalline compound, the compositions are classified into composition (a) and composition (b). The composition (a) may contain other liquid crystalline compounds, additives, and the like in addition to the liquid crystalline compound selected from the compounds (1), (2), and (3). The "other liquid crystalline compound" is a liquid crystalline compound different from the compound (1), the compound (2) and the compound (3). Such compounds are mixed in the composition for the purpose of further adjusting the properties.

The composition (b) substantially contains only a liquid crystalline compound selected from the group consisting of the compound (1), the compound (2) and the compound (3). "substantially" means that the composition (b) may contain additives, but does not contain other liquid crystalline compounds. The amount of the component of composition (b) is small compared to composition (a). From the viewpoint of cost reduction, the composition (b) is superior to the composition (a). The composition (a) is superior to the composition (b) in that the properties can be further adjusted by mixing other liquid crystalline compounds.

Second, the main characteristics of the component compounds and the main effects of the compounds on the composition or element will be described. The main properties of the component compounds based on the effects of the present invention are summarized in Table 2. In the notation of Table 2, L means large or high, M means medium, and S means small or low. The notation L, M, S is a classification based on qualitative comparisons between component compounds, with 0 (zero) meaning less than S.

TABLE 2 Properties of liquid crystalline Compounds

Compound (I)	Compound (1)	Compound (2)	Compound (3)
				Upper limit temperature	L	S～L	S～M
Viscosity of the oil	M	M～L	S
				Optical anisotropy	M	M～L	S～L
Dielectric anisotropy	0	M～L¹⁾	0
				Specific resistance	L	L	L

1) The dielectric anisotropy is negative, and the notation indicates the magnitude of the absolute value.

The main effects of the component compounds are as follows. The compound (1) increases the upper limit temperature. The compound (2) improves the dielectric anisotropy. The compound (3) lowers the viscosity. Since the compound (4) is polymerizable, it forms a polymer by polymerization. The polymer stabilizes the alignment of liquid crystal molecules, thereby shortening the response time of the element and improving the afterimage of an image.

Thirdly, combinations of the component compounds in the composition, preferable ratios and their basis are explained. Preferred combinations of the component compounds in the composition are compound (1) + compound (2), compound (1) + compound (3), compound (1) + compound (2) + compound (4), compound (1) + compound (3) + compound (4), or compound (1) + compound (2) + compound (3) + compound (4). Further preferred combinations are compound (1) + compound (2) + compound (3) or compound (1) + compound (2) + compound (3) + compound (4).

The preferable proportion of the compound (1) is about 3% by mass or more for increasing the upper limit temperature, and about 30% by mass or less for decreasing the lower limit temperature. Further, the preferable ratio is in the range of about 5% by mass to about 20% by mass. A particularly preferred ratio is in the range of about 5% to about 15% by mass.

The preferable proportion of the compound (2) is about 10% by mass or more for improving the dielectric anisotropy, and the preferable proportion of the compound (2) is about 90% by mass or less for lowering the lower limit temperature. Further, the preferable ratio is in the range of about 15 mass% to about 85 mass%. A particularly preferred ratio is in the range of about 20% by mass to about 80% by mass.

The preferable proportion of the compound (3) is about 10% by mass or more for lowering the viscosity, and about 90% by mass or less for improving the dielectric anisotropy. Further, the preferable ratio is in the range of about 15% by mass to about 80% by mass. A particularly preferred ratio is in the range of about 20% by mass to about 70% by mass.

The compound (4) is added to the composition for the purpose of being suitable for a polymer stable alignment type element. The preferable proportion of the compound (4) is about 0.03% by mass or more for aligning liquid crystal molecules, and about 10% by mass or less for preventing display defects of the device. Further, the preferable ratio is in the range of about 0.1% by mass to about 2% by mass. A particularly preferred ratio is in the range of about 0.2% to about 1.0% by mass.

Fourth, preferred embodiments of the component compounds will be described. In the formulae (1), (2) and (3), R¹And R²Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine. Preferred R for reducing viscosity¹Or R²An alkenyl group having 2 to 12 carbon atoms, and R is preferably selected for the purpose of improving stability¹Or R²Is an alkyl group having 1 to 12 carbon atoms. R³And R⁴Is hydrogen, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, alkenyl group having 2 to 12 carbon atoms, alkenyloxy group having 2 to 12 carbon atoms, or alkyl group having 1 to 12 carbon atoms wherein at least one hydrogen is substituted with fluorine or chlorine. For improved stability, R is preferred³Or R⁴Is an alkyl group having 1 to 12 carbon atoms, and R is preferably selected to improve dielectric anisotropy³Or R⁴Is an alkoxy group having 1 to 12 carbon atoms, preferably R for the purpose of reducing viscosity and lowering threshold voltage³Or R⁴Is an alkenyl group having 2 to 12 carbon atoms. R⁵And R⁶Is alkyl group with carbon number of 1-12, alkoxy group with carbon number of 1-12, alkenyl group with carbon number of 2-12, at least one hydrogen groupA fluorine or chlorine substituted alkyl group having 1 to 12 carbon atoms, or a fluorine or chlorine substituted alkenyl group having 2 to 12 carbon atoms in which at least one hydrogen is substituted. Preferred R for reducing viscosity⁵Or R⁶An alkenyl group having 2 to 12 carbon atoms, and R is preferably selected for the purpose of improving stability⁵Or R⁶Is an alkyl group having 1 to 12 carbon atoms.

Preferred alkyl groups are methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl or octyl. Further preferred alkyl groups for reducing the viscosity are methyl, ethyl, propyl, butyl or pentyl.

Preferred alkoxy groups are methoxy, ethoxy, propoxy, butoxy, pentoxy, hexoxy or heptoxy. Further preferred alkoxy groups for reducing the viscosity are methoxy or ethoxy.

Preferred alkenyl groups are vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl or 5-hexenyl. Further preferred alkenyl groups for reducing the viscosity are vinyl, 1-propenyl, 3-butenyl or 3-pentenyl. The preferred steric configuration of-CH ═ CH-in these alkenyl groups depends on the position of the double bond. In order to reduce viscosity and the like, the trans configuration is preferable among alkenyl groups such as 1-propenyl, 1-butenyl, 1-pentenyl, 1-hexenyl, 3-pentenyl, 3-hexenyl. Among alkenyl groups such as 2-butenyl, 2-pentenyl, 2-hexenyl, the cis configuration is preferred.

Preferred alkenyloxy groups are vinyloxy, allyloxy, 3-butenyloxy, 3-pentenyloxy or 4-pentenyloxy. Further preferred alkenyloxy groups are allyloxy or 3-butenyloxy groups in order to reduce the viscosity.

Preferred examples of alkyl groups in which at least one hydrogen is replaced by fluorine or chlorine are fluoromethyl, 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl, 5-fluoropentyl, 6-fluorohexyl, 7-fluoroheptyl or 8-fluorooctyl. Further preferable examples of the compound include 2-fluoroethyl, 3-fluoropropyl, 4-fluorobutyl and 5-fluoropentyl for improving the dielectric anisotropy.

Preferred examples of alkenyl groups in which at least one hydrogen is substituted by fluorine or chlorine are 2, 2-difluorovinyl, 3-difluoro-2-propenyl, 4-difluoro-3-butenyl, 5-difluoro-4-pentenyl or 6, 6-difluoro-5-hexenyl. Further preferable examples for lowering the viscosity are 2, 2-difluorovinyl group and 4, 4-difluoro-3-butenyl group.

Ring A and ring C are 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, or chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine. Preferred examples of "1, 4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine" are 2-fluoro-1, 4-phenylene, 2, 3-difluoro-1, 4-phenylene or 2-chloro-3-fluoro-1, 4-phenylene. The ring A or the ring C is preferably a 1, 4-cyclohexylene group for lowering the viscosity, the tetrahydropyran-2, 5-diyl group for raising the upper limit temperature, and the 1, 4-phenylene group for raising the optical anisotropy. Tetrahydropyran-2, 5-diyl in ring a and ring C is:

preferably:

ring B is 2, 3-difluoro-1, 4-phenylene, 2-chloro-3-fluoro-1, 4-phenylene, 2, 3-difluoro-5-methyl-1, 4-phenylene, 3,4, 5-trifluoronaphthalene-2, 6-diyl, 7, 8-difluorochromane-2, 6-diyl, 3,4,5, 6-tetrafluorofluorene-2, 7-diyl (FLF4), 4, 6-difluorodibenzofuran-3, 7-diyl (DBTF2), 4, 6-difluorodibenzothiophene-3, 7-diyl (DBTF2), or 1,1,6, 7-tetrafluoroindan-2, 5-diyl (InF 4).

The preferred ring B is 2, 3-difluoro-1, 4-phenylene for viscosity reduction and 4, 6-difluorodibenzothiophene-3, 7-diyl for dielectric anisotropy improvement.

And ring D and ring E are 1, 4-cyclohexylene, 1, 4-phenylene, 2-fluoro-1, 4-phenylene or 2, 5-difluoro-1, 4-phenylene. For lowering the viscosity or for increasing the upper temperature limit, the preferred ring D or E is 1, 4-cyclohexylene, and for lowering the lower temperature limit, the preferred ring D or E is 1, 4-phenylene.

Z¹、Z²And Z³Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy. For reducing the viscosity, preferred is Z¹、Z²Or Z³Is a single bond. Z⁴And Z⁵Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy. For reducing the viscosity, preferred is Z⁴Or Z⁵Is a single bond, and Z is preferably Z for lowering the lower limit temperature⁴Or Z⁵Is ethylene, and Z is preferably selected to improve the dielectric anisotropy⁴Or Z⁵Is methyleneoxy. Z⁶Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy. For reducing the viscosity, preferred is Z⁶Is a single bond.

Divalent radicals such as methyleneoxy are asymmetric to the left and right. In the methyleneoxy group, -CH₂O-is superior to-OCH₂-. In the carbonyloxy group, -COO-is preferable to-OCO-.

a is 0, 1,2 or 3, b is 0 or 1, and the sum of a and b is 3 or less. For lowering the viscosity, a is preferably 1, and for raising the upper limit temperature, a is preferably 2 or 3. For lowering the viscosity, b is preferably 0, and for lowering the lower limit temperature, b is preferably 1. c is 1 or 2. For lowering the viscosity, c is preferably 1, and for raising the upper limit temperature, c is preferably 2.

In the formula (4), the ring F and the ring J are cyclohexyl, cyclohexenyl, phenyl, 1-naphthyl, 2-naphthyl, tetrahydropyran-2-yl, 1, 3-dioxane-2-yl, pyrimidin-2-yl or pyridin-2-yl, and in these rings, at least one hydrogen may be substituted with fluorine, chlorine, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkyl group having 1 to 12 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine. Preferred ring F or ring J is phenyl. Ring G is 1, 4-cyclohexylene, 1, 4-cyclohexenylene, 1, 4-phenylene, naphthalene-1, 2-diyl, naphthalene-1, 3-diyl, naphthalene-1, 4-diyl, naphthalene-1, 5-diyl, naphthalene-1, 6-diyl, naphthalene-1, 7-diyl, naphthalene-1, 8-diyl, naphthalene-2, 3-diyl, naphthalene-2, 6-diyl, naphthalene-2, 7-diyl, tetrahydropyran-2, 5-diyl, 1, 3-dioxane-2, 5-diyl, pyrimidine-2, 5-diyl or pyridine-2, 5-diyl, and in these rings, at least one hydrogen may be substituted with fluorine, chlorine, an alkyl group having a carbon number of 1 to 12, an alkoxy group having a carbon number of 1 to 12, Or at least one hydrogen is substituted with a fluorine or chlorine substituted alkyl group having 1 to 12 carbon atoms. Preferred ring G is 1, 4-phenylene or 2-fluoro-1, 4-phenylene.

Z⁷And Z⁸Is a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -CO-, -COO-or-OCO-, at least one-CH₂CH₂-may be via-CH ═ CH-, -C (CH)₃)＝CH-、-CH＝C(CH₃) -or-C (CH)₃)＝C(CH₃) -substitution, of which at least one hydrogen may be substituted by fluorine or chlorine. Preferred Z⁷Or Z⁸Is a single bond, -CH₂CH₂-、-CH₂O-、-OCH₂-, -COO-or-OCO-. Further preferred is Z⁷Or Z⁸Is a single bond.

Sp¹To Sp³Is a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine. Preferred is Sp¹To Sp³Is a single bond, -CH₂CH₂-、-CH₂O-、-OCH₂-, -COO-, -OCO-, -CO-CH-or-CH-CO-. Further preferred is Sp¹To Sp³Is a single bond.

d is 0, 1 or 2. Preferably d is 0 or 1. e. f and g are 0, 1,2, 3 or 4, and the sum of e, f and g is 1 or more. Preferred e, f or g is 1 or 2.

P¹To P³Is a polymerizable group. Preferred P¹To P³Is a polymerizable group selected from the group represented by the formulae (P-1) to (P-5). Further preferred is P¹To P³Is a group represented by the formula (P-1), the formula (P-2) or the formula (P-3). Particularly preferred P¹To P³Is a group represented by the formula (P-1) or (P-2). Most preferred P¹To P³Is a group represented by the formula (P-1). The preferred group represented by the formula (P-1) is-OCO-CH ═ CH₂or-OCO-C (CH)₃)＝CH₂. The wavy lines of the formulae (P-1) to (P-5) indicate the sites of bonding.

In the formulae (P-1) to (P-5), M¹To M³Hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine. For the purpose of enhancing reactivity, M is preferred¹To M³Is hydrogen or methyl. Further preferred is M¹Hydrogen or methyl, further preferred M²Or M³Is hydrogen.

In formulae (4-1) to (4-29), P⁴To P⁶Are a group represented by the formulae (P-1) to (P-3). Preferred P⁴To P⁶Is represented by formula (P-1) or formula (P-2). Still more preferred formula (P-1) is-OCO-CH ═ CH₂or-OCO-C (CH)₃)＝CH₂. The wavy lines of the formulae (P-1) to (P-3) indicate the bonding sites.

Fifth, preferred component compounds are shown. Preferred compounds (1) are R¹Is alkenyl of 2 to 12 carbon atoms and R²A compound which is an alkyl group having 1 to 12 carbon atoms. Further preferred compound (1) is R¹Is alkenyl of 2 to 5 carbon atoms and R²A compound which is an alkyl group having 1 to 5 carbon atoms. Particularly preferred compounds (1) are R¹Is alkenyl of 2 or 3 carbon atoms and R²A compound which is an alkyl group having 2 or 3 carbon atoms.

Preferred compound (2) is the compound (2-1) to the compound (2-35) described in the item 4. Of these compounds, it is preferable that at least one of the components B is the compound (2-1), the compound (2-3), the compound (2-6), the compound (2-8), the compound (2-10), the compound (2-14) or the compound (2-16). Preferably, at least two of the components B are a combination of the compound (2-1) and the compound (2-8), the compound (2-1) and the compound (2-14), the compound (2-3) and the compound (2-8), the compound (2-3) and the compound (2-14), the compound (2-3) and the compound (2-16), the compound (2-6) and the compound (2-8), the compound (2-6) and the compound (2-10), or the compound (2-6) and the compound (2-14).

Preferred compound (3) is the compound (3-1) to the compound (3-9) described in the item 7. Of these compounds, it is preferable that at least one of the components C is the compound (3-1), the compound (3-3), the compound (3-5), the compound (3-6), the compound (3-8) or the compound (3-9). Preferably, at least two of the components C are a combination of the compound (3-1) and the compound (3-3), the compound (3-1) and the compound (3-5), or the compound (3-1) and the compound (3-6).

Preferred compound (4) is the compound (4-1) to the compound (4-29) described in the item 11. Of these compounds, it is preferable that at least one of the additives X is the compound (4-1), the compound (4-2), the compound (4-24), the compound (4-25), the compound (4-26) or the compound (4-27). Preferably, at least two of the additives X are a combination of the compound (4-1) and the compound (4-2), the compound (4-1) and the compound (4-18), the compound (4-2) and the compound (4-24), the compound (4-2) and the compound (4-25), the compound (4-2) and the compound (4-26), the compound (4-25) and the compound (4-26), or the compound (4-18) and the compound (4-24).

Sixth, additives that can be added to the composition will be described. Such additives include optically active compounds, antioxidants, ultraviolet absorbers, delustering agents, pigments, antifoaming agents, polymerizable compounds, polymerization initiators, polymerization inhibitors, polar compounds, and the like. An optically active compound is added to the composition for the purpose of inducing a helical structure of liquid crystal molecules to impart a twist angle (torsion angle). Examples of such compounds are compound (5-1) to compound (5-5). The preferable proportion of the optically active compound is about 5% by mass or less. Further, the preferable ratio is in the range of about 0.01 to about 2 mass%.

In order to prevent a decrease in specific resistance caused by heating in the atmosphere or to maintain a large voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature after the device is used for a long time, an antioxidant such as the compounds (6-1) to (6-3) may be further added to the composition.

Since the compound (6-2) has low volatility, it is effective for maintaining a large voltage holding ratio not only at room temperature but also at a temperature close to the upper limit temperature after the device is used for a long time. In order to obtain the above effect, the preferable ratio of the antioxidant is about 50ppm or more, and in order not to lower the upper limit temperature or to raise the lower limit temperature, the preferable ratio of the antioxidant is about 600ppm or less. Even more preferred ratios range from about 100ppm to about 300 ppm.

Preferable examples of the ultraviolet absorber include benzophenone derivatives, benzoate derivatives, triazole derivatives and the like. Light stabilizers such as sterically hindered amines are also preferred. Preferable examples of the light stabilizer are compound (7-1) to compound (7-16) and the like. The preferable proportion of these absorbents or stabilizers is about 50ppm or more in order to obtain the above effects, and about 10000ppm or less in order not to lower the upper limit temperature or not to raise the lower limit temperature. Even more preferred ratios range from about 100ppm to about 10000 ppm.

The matting agent is a compound that receives light energy absorbed by the liquid crystalline compound and converts the light energy into thermal energy to prevent decomposition of the liquid crystalline compound. Preferable examples of the matting agent are a compound (8-1) to a compound (8-7), and the like. The preferable proportion of these matting agents is about 50ppm or more in order to obtain the above effects, and about 20000ppm or less in order not to raise the lower limit temperature. Even more preferred ratios range from about 100ppm to about 10000 ppm.

Dichroic dyes (dichromatic dye) such as azo-based pigments, anthraquinone-based pigments, etc. are added to the composition in order to be suitable for guest-host (GH) mode elements. The preferable ratio of the pigment ranges from about 0.01% by mass to about 10% by mass. In order to prevent bubbling, an antifoaming agent such as dimethylsilicone oil or methylphenylsilicone oil is added to the composition. The preferable ratio of the defoaming agent is about 1ppm or more in order to obtain the above effects, and about 1000ppm or less in order to prevent display failure. Even more preferred ratios range from about 1ppm to about 500 ppm.

Polymerizable compounds are used to adapt to polymer-stabilized alignment (PSA) type devices. The compounds (4) are suitable for this purpose. A polymerizable compound different from the compound (4) may be added to the composition together with the compound (4). Preferable examples of such polymerizable compounds are compounds such as acrylic acid esters, methacrylic acid esters, vinyl compounds, vinyloxy compounds, propenyl ethers, epoxy compounds (oxetane ) and vinyl ketones. Further preferred are derivatives of acrylic acid esters or methacrylic acid esters. The preferable proportion of the compound (4) is 10% by mass or more based on the total mass of the polymerizable compound. Further, the preferable ratio is 50% by mass or more. The ratio is particularly preferably 80% by mass or more. The most preferable ratio is 100 mass%.

The polymerizable compound such as the compound (4) is polymerized by ultraviolet irradiation. The polymerization may be carried out in the presence of an appropriate initiator such as a photopolymerization initiator. Suitable conditions for carrying out the polymerization, suitable types of initiators, and suitable amounts are known to those skilled in the art and are described in the literature. For example, brilliant good solid (Irgacure)651 (registered trademark; BASF), brilliant good solid (Irgacure)184 (registered trademark; BASF) or Delocur (Darocur)1173 (registered trademark; BASF) as a photopolymerization initiator is suitable for radical polymerization. The preferable proportion of the photopolymerization initiator ranges from about 0.1% by mass to about 5% by mass based on the total mass of the polymerizable compound. Further, the preferable ratio is in the range of about 1% by mass to about 3% by mass.

When storing the polymerizable compound such as the compound (4), a polymerization inhibitor may be added to prevent polymerization. The polymerizable compound is usually added to the composition in a state where the polymerization inhibitor is not removed. Examples of the polymerization inhibitor are hydroquinone, hydroquinone derivatives such as methyl hydroquinone, 4-t-butyl catechol, 4-methoxyphenol, phenothiazine (phenothiazine), and the like.

Seventh, a method for synthesizing the component compound will be explained. These compounds can be synthesized by known methods. A synthesis method is exemplified. Compound (1) is synthesized by the method described in Japanese patent laid-open publication No. 58-194822. The compound (2-1) is synthesized by the method described in Japanese patent laid-open No. Hei 2-503441. The compound (3-5) is synthesized by the method described in Japanese patent laid-open No. 57-165328. The compound (4-18) is synthesized by the method described in Japanese patent laid-open No. Hei 7-101900. Antioxidants are commercially available. Compound (6-1) is available from Sigma Aldrich Corporation. The compound (6-2) and the like are synthesized by the method described in the specification of U.S. Pat. No. 3660505.

Compounds not described in the synthetic methods can be synthesized by methods described in the patent publications such as Organic Synthesis (John Wiley & Sons, Inc.), "Organic Reactions (Organic Reactions, John Wiley & Sons, Inc.)," Integrated Organic Synthesis (Pergamon Press), New Experimental chemistry lecture (Bolus), and the like. The compositions are prepared by known methods from the compounds obtained in the manner described. For example, the component compounds are mixed and then dissolved in each other by heating.

Finally, the use of the composition is illustrated. The composition has a major amount of optical anisotropy having a lower temperature limit of about-10 ℃ or less, an upper temperature limit of about 70 ℃ or more, and a range of about 0.07 to about 0.20. A composition having an optical anisotropy in the range of about 0.08 to about 0.25 may also be prepared by controlling the ratio of the component compounds, or by mixing other liquid crystalline compounds. Compositions having optical anisotropy in the range of about 0.10 to about 0.30 may also be prepared by trial and error. The device containing the composition has a large voltage holding ratio. The composition is suitable for AM elements. The composition is particularly suitable for transmissive AM elements. The composition can be used as a composition having a nematic phase, and can be used as an optically active composition by adding an optically active compound.

The composition can be used in AM elements. And can also be used for PM elements. The composition can be used for AM elements and PM elements having modes such as PC, TN, STN, ECB, OCB, IPS, FFS, VA, FPA and the like. Particularly preferably for AM elements having TN, OCB, IPS mode or FFS mode. In an AM element having an IPS mode or an FFS mode, the alignment of liquid crystal molecules may be parallel or may be perpendicular to a glass substrate when no voltage is applied. These elements may be reflective, transmissive or transflective. Preferably for use in transmissive devices. It can also be used for an amorphous silicon-TFT element or a polysilicon-TFT element. The composition may be used for a device of a Nematic Curvilinear Aligned Phase (NCAP) type prepared by microencapsulation (microencapsulation) or a device of a Polymer Dispersed (PD) type in which a three-dimensional network polymer is formed in the composition.

[ examples ]

The present invention will be described in more detail by way of examples. The present invention is not limited to these examples. The invention comprises a mixture of the composition of example 1 and the composition of example 2. The invention also includes mixtures of at least two of the compositions of the examples. The synthesized compound is identified by Nuclear Magnetic Resonance (NMR) analysis or the like. The properties of the compounds, compositions and devices were measured by the methods described below.

NMR analysis: DRX-500 manufactured by Bruker BioSpin was used for the measurement. In that¹In the measurement of H-NMR, a sample was dissolved in CDCl₃The measurement was performed in a deuterated solvent at room temperature under conditions of 500MHz and 16 cumulative times. Tetramethylsilane was used as an internal standard. In that¹⁹In the measurement of F-NMR, CFCl was used₃As an internal standard, the number of times is accumulated to 24 times. In the description of the nmr spectra, s is a singlet (singlet), d is a doublet (doublt), t is a triplet (triplet), q is a quartet (quatet), quin is a quintet (quintet), sex is a sextant (sextet), m is a multiplet (multiplet), and br is a broad (broad).

Gas chromatographic analysis: for measurement, a GC-14B gas chromatograph manufactured by Shimadzu corporation was used. The carrier gas was helium (2 mL/min). The sample vaporizer was set at 280 ℃ and the detector (flame ionization detector, FID) was set at 300 ℃. The separation of the component compounds was carried out by using a capillary column DB-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm; stationary liquid phase is dimethylpolysiloxane; non-polar) manufactured by Agilent Technologies Inc. After the column was held at 200 ℃ for 2 minutes, the temperature was raised to 280 ℃ at a rate of 5 ℃/min. After preparing the sample into an acetone solution (0.1 mass%), 1. mu.L of the acetone solution was injected into the sample vaporization chamber. The record is a chromatograph module (Chromatopac) model C-R5A manufactured by Shimadzu corporation or an equivalent thereof. The obtained gas chromatogram showed the retention time of the peak corresponding to the component compound and the area of the peak.

Chloroform, hexane, and the like can be used as a solvent for diluting the sample. To separate the constituent compounds, the following capillary column may be used. HP-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm) manufactured by Agilent Technologies Inc., Rtx-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm) manufactured by Rasteck Corporation, BP-1 (length 30m, inner diameter 0.32mm, film thickness 0.25 μm) manufactured by Australian SGE International Pty.Ltd. For the purpose of preventing overlapping of compound peaks, capillary columns manufactured by Shimadzu corporation CBP1-M50-025 (length 50M, inner diameter 0.25mm, film thickness 0.25 μ M) were used.

The ratio of the liquid crystalline compound contained in the composition can be calculated by the following method. The mixture of liquid crystalline compounds was analyzed by gas chromatography (FID). The area ratio of the peaks in the gas chromatogram corresponds to the ratio of the liquid crystalline compound. When the capillary column described above is used, the correction coefficient of each liquid crystalline compound can be regarded as 1. Therefore, the ratio (% by mass) of the liquid crystalline compound can be calculated from the area ratio of the peak.

Measurement of the sample: in the measurement of the properties of the composition or the element, the composition is used as a sample as it is. In order to measure the characteristics of the compound, a sample for measurement was prepared by mixing the compound (15 mass%) in a mother liquid crystal (85 mass%). From the values obtained by the measurement, the characteristic values of the compounds were calculated by an extrapolation method (extrapolation method). (extrapolated value) { (measured value of sample) — 0.85 × (measured value of mother liquid crystal) }/0.15. When a smectic phase (or crystal) precipitates at 25 ℃ at the ratio, the ratio of the compound to the mother liquid crystal is set at 10 mass%: 90% by mass and 5% by mass: 95% by mass and 1% by mass: the order of 99 mass% was changed. The values of the upper limit temperature, optical anisotropy, viscosity and dielectric anisotropy relating to the compound were determined by the extrapolation method.

The following mother liquid crystal was used. The proportion of the component compounds is represented by mass%.

The determination method comprises the following steps: the characteristics were measured by the following methods. These methods are mostly described in JEITA standard (JEITA. ED-2521B) examined and established by the Japan electronic Information Technology Industries Association (JEITA), or modified. The TN element used for the measurement was not provided with a Thin Film Transistor (TFT).

(1) Upper limit temperature of nematic phase (NI;. degree. C.): the sample was placed on a hot plate of a melting point measuring apparatus equipped with a polarizing microscope, and heated at a rate of 1 ℃/min. The temperature at which a portion of the sample changes from a nematic phase to an isotropic liquid is measured. The upper limit temperature of the nematic phase is sometimes abbreviated as "upper limit temperature".

(2) Lower limit temperature (T) of nematic phase_C(ii) a C): the nematic phase was observed after placing the sample in a glass bottle and keeping the bottle in a freezer at 0 ℃, -10 ℃, -20 ℃, -30 ℃ and-40 ℃ for 10 days. For example, when the sample is kept in a nematic phase at-20 ℃ and changes to a crystalline or smectic phase at-30 ℃, it is described as T_C<-20 ℃. The lower limit temperature of the nematic phase is sometimes abbreviated as "lower limit temperature".

(3) Viscosity (. eta.; measured at 20 ℃ C.; mPas): for the measurement, an E-type rotational viscometer manufactured by tokyo counter gmbh was used.

(4) Viscosity (rotational viscosity; γ 1; measured at 25 ℃; mPas): for the measurement, a rotational viscosity ratio measuring system LCM-2 of Toyo technology (TOYOTechnica) Co., Ltd was used. A VA device having a gap (cell gap) of 10 μm between two glass substrates was used as a sample. A rectangular wave (55V, 1ms) was applied to the element. The peak current (peak current) and peak time (peak time) of the transient current (transient current) generated by the application are measured. The values of rotational viscosity were obtained using these measured values and dielectric anisotropy. The dielectric anisotropy was measured by the method described in measurement (6).

(5) Optical anisotropy (refractive index anisotropy; Δ n; measured at 25 ℃): the measurement was performed by an Abbe refractometer having a polarizer attached to an eyepiece lens, using light having a wavelength of 589 nm. After rubbing the surface of the primary prism in one direction, the sample was dropped onto the primary prism. The refractive index n/is measured when the direction of polarization is parallel to the direction of rubbing. The refractive index n ″) is measured when the direction of the polarized light is perpendicular to the direction of the friction. The value of the optical anisotropy is calculated from the formula Δ n ═ n/n ″.

(6) Dielectric anisotropy (. DELTA.; measured at 25 ℃): the value of the dielectric anisotropy is calculated according to the formula Δ ═/. The dielectric constant (/ and ≠ T) was measured as follows.

1) Determination of dielectric constant (/): a solution of octadecyltriethoxysilane (0.16mL) in ethanol (20mL) was coated on the well-cleaned glass substrate. The glass substrate was rotated by a rotator and then heated at 150 ℃ for 1 hour. A VA cell having a gap (cell gap) of 4 μm between two glass substrates was loaded with a sample, and the cell was sealed with an adhesive cured by ultraviolet light. A sine wave (0.5V, 1kHz) was applied to the cell, and the dielectric constant (/) in the long axis direction of the liquid crystal molecules was measured after 2 seconds.

2) Determination of dielectric constant (. DELTA.): the polyimide solution was coated on the well-cleaned glass substrate. After the glass substrate is fired, the obtained alignment film is subjected to rubbing treatment. A sample was placed in a TN cell having a cell gap of 9 μm and a twist angle of 80 degrees between two glass substrates. Sine wave (0.5V, 1kHz) was applied to the element, and the dielectric constant (#) in the short axis direction of the liquid crystal molecules was measured after 2 seconds.

(7) Threshold voltage (Vth; measured at 25 ℃; V): for measurement, a luminance meter model LCD5100 manufactured by tsukamur electronics gmbh was used. The light source is a halogen lamp. A VA element of a normally black mode (normal black mode) in which the interval (cell gap) between two glass substrates was 4 μm and the rubbing directions were antiparallel was loaded with a sample, and the element was sealed using an adhesive hardened by ultraviolet rays. The voltage applied to the element (60Hz, square wave) was increased from 0V to 20V in a stepwise manner in units of 0.02V. At this time, the element was irradiated with light from the vertical direction, and the amount of light transmitted through the element was measured. A voltage-transmittance curve was prepared in which the transmittance was 100% when the light amount reached the maximum and the transmittance was 0% when the light amount was the minimum. The threshold voltage is represented by a voltage at which the transmittance becomes 10%.

(8) Voltage holding ratio (VHR-1; measured at 25;%): the TN element used for the measurement had a polyimide alignment film, and the interval (cell gap) between the two glass substrates was 5 μm. The element is sealed with an adhesive hardened by ultraviolet rays after the sample is put in. The TN cell was charged by applying a pulse voltage (5V, 60 μ sec). The decayed voltage was measured by a high-speed voltmeter over a period of 16.7 milliseconds, and the area a between the voltage curve per unit cycle and the horizontal axis was determined. The area B is the area when not attenuated. The voltage holding ratio is expressed by a percentage of the area a to the area B.

(9) Voltage holding ratio (VHR-2; measured at 80;%): the voltage holding ratio was measured in the same procedure as described except that the measurement was performed at 80 ℃ instead of 25 ℃. The obtained value is represented by VHR-2.

(10) Voltage holding ratio (VHR-3; measured at 25;%): after irradiation with ultraviolet light, the voltage holding ratio was measured to evaluate the stability to ultraviolet light. The TN cells used for the measurement had a polyimide alignment film and a cell gap of 5 μm. The sample was injected into the cell and irradiated with light for 20 minutes. The light source was an ultra-high pressure mercury lamp USH-500D (manufactured by Ushio motor), and the spacing between the elements and the light source was 20 cm. In the measurement of VHR-3, the voltage at decay was measured over a period of 16.7 milliseconds. Compositions with large VHR-3 have a large stability to UV light. VHR-3 is preferably 90% or more, more preferably 95% or more.

(11) Voltage holding ratio (VHR-4; measured at 25;%): the TN elements impregnated with the samples were heated in a thermostatic bath at 80 ℃ for 500 hours, and then the voltage holding ratio was measured to evaluate the stability to heat. In the measurement of VHR-4, the voltage at decay was measured over a period of 16.7 milliseconds. Compositions with large VHR-4 have a large stability to heat.

(12) Response time (. tau.; measured at 25 ℃ C.; ms): for measurement, a luminance meter model LCD5100 manufactured by tsukamur electronics gmbh was used. The light source is a halogen lamp. The Low pass filter (Low-pass filter) was set to 5 kHz. The sample was placed in a VA element of a normally black mode (normal black mode) in which the interval (cell gap) between two glass substrates was 4 μm and the rubbing directions were antiparallel. The element is sealed using an adhesive hardened by ultraviolet rays. A square wave (60Hz, 10V, 0.5 sec) was applied to the element. At this time, the element was irradiated with light from the vertical direction, and the amount of light transmitted through the element was measured. The transmittance was regarded as 100% when the amount of light reached the maximum, and 0% when the amount of light was the minimum. The response time is represented by the time (fall time; millisecond) required for the transmittance to change from 90% to 10%.

(13) Specific resistance (. rho.; measured at 25 ℃ C.;. omega. cm): 1.0mL of the sample was injected into a container equipped with an electrode. A DC voltage (10V) was applied to the vessel, and a DC current after 10 seconds was measured. The specific resistance is calculated according to the following equation. (specific resistance) { (voltage) × (capacitance of container) }/{ (direct current) × (dielectric constant of vacuum) }.

(14) Line afterimage (Line Image learning Parameter); LISP;%): the liquid crystal display element is electrically stressed to generate a line residual image. The luminance of the region where the line afterimage exists and the luminance of the remaining region are measured. The ratio of the luminance decrease is calculated from the line afterimage, and the size of the line afterimage is represented by the ratio.

14a) Measurement of luminance: an image of the device was captured using an imaging color luminance meter (PM-1433F-0 manufactured by Ration Zemax, Inc.). The brightness of each region of the element was calculated by analyzing the image using software (promisco 9.1, manufactured by radial Imaging). Average luminance of 3500cd/m used for light source²A light-emitting diode (LED) backlight.

14b) Setting of stress voltage: a sample was placed in an FFS cell (16 cells of 4 cells in the vertical direction × 4 cells in the horizontal direction) having a cell gap of 3.5 μm and a matrix structure, and the cell was sealed with an adhesive cured by ultraviolet light. Polarizing plates are disposed on the upper and lower surfaces of the element so that the polarizing axes are orthogonal to each other. Light was irradiated to the element, and a voltage (rectangular wave, 60Hz) was applied. The brightness of the transmitted light at each voltage was measured by increasing the voltage in 0.1V stepwise in the range of 0V to 7.5V. The voltage at which the luminance reaches the maximum is abbreviated as V255. The voltage at which the luminance becomes 21.6% of V255 (i.e., 127 steps) is abbreviated as V127.

14c) Conditions of stress: v255 (square wave, 30Hz) and 0.5V (square wave, 30Hz) were applied to the element at 60 ℃ for 23 hours, so that a checkerboard pattern was displayed (checker pattern). Next, V127 (square wave, 0.25Hz) was applied, and the brightness was measured under the condition of an exposure time of 4000 milliseconds.

14d) Calculation of line afterimage: the calculation was performed using 4 cells (vertical 2 cells × horizontal 2 cells) in the center of the 16 cells. The 4 cells were divided into 25 regions (vertical 5 cells × horizontal 5 cells). The average luminance of 4 regions (2 cells in vertical direction × 2 cells in horizontal direction) located at the four corners is abbreviated as luminance a. The area excluding the four corner areas from the 25 areas is a cross. Among 4 regions excluding the central intersection region from the cross-shaped region, the minimum value of the luminance is abbreviated as luminance B. The line residual image is calculated according to the following equation. (line afterimage) (luminance a-luminance B)/luminance a × 100.

(15) Ductility: the ductility of the additive was qualitatively evaluated by applying a voltage to the element and measuring the luminance. The measurement of the luminance was performed in the same manner as in the item 14 a. The voltage (V127) is set in the same manner as in the above-described item 14 b. In which VA elements are used instead of FFS elements. The brightness was measured in the following manner. First, a dc voltage (2V) was applied to the element for 2 minutes. Next, V127 (square wave, 0.05Hz) was applied, and the brightness was measured under the condition of an exposure time of 4000 milliseconds. The ductility was evaluated from the results.

(16) Response time (. tau. -2; measured at-20 ℃ C.; ms): for measurement, a luminance meter model LCD5100 manufactured by tsukamur electronics gmbh was used. The light source is a halogen lamp. The Low pass filter (Low-pass filter) was set to 5 kHz. The sample was placed in a VA element of a normally black mode (normal black mode) in which the interval (cell gap) between two glass substrates was 4 μm and the rubbing directions were antiparallel. The element is sealed using an adhesive hardened by ultraviolet rays. A square wave (60Hz, 10V, 0.5 sec) was applied to the element. At this time, the element was irradiated with light from the vertical direction, and the amount of light transmitted through the element was measured. The transmittance was regarded as 100% when the amount of light reached the maximum, and 0% when the amount of light was the minimum. The response time is represented by the time (fall time; millisecond) required for the transmittance to change from 90% to 10%.

(17) Response time (. tau. -3; measured at-30 ℃ C.; ms): for measurement, a luminance meter model LCD5100 manufactured by tsukamur electronics gmbh was used. The light source is a halogen lamp. The Low pass filter (Low-pass filter) was set to 5 kHz. The sample was placed in a VA element of a normally black mode (normal black mode) in which the interval (cell gap) between two glass substrates was 4 μm and the rubbing directions were antiparallel. The element is sealed using an adhesive hardened by ultraviolet rays. A square wave (60Hz, 10V, 0.5 sec) was applied to the element. At this time, the element was irradiated with light from the vertical direction, and the amount of light transmitted through the element was measured. The transmittance was regarded as 100% when the amount of light reached the maximum, and 0% when the amount of light was the minimum. The response time is represented by the time (fall time; millisecond) required for the transmittance to change from 90% to 10%.

Examples of compositions are shown below. The component compounds are represented by symbols based on the definitions in table 3 below. In Table 3, the configuration of the 1, 4-cyclohexylene group-related solid is trans configuration. The numbers in parentheses after the symbols correspond to the numbers of the compounds. The symbol (-) indicates other liquid crystalline compounds. The ratio (percentage) of the liquid crystalline compound is a mass percentage (mass%) based on the mass of the liquid crystal composition. Finally, the values of the properties of the composition are summarized.

TABLE 3 expression of Compounds Using symbols

R-(A₁)-Z₁-·····-Z_n-(A_n)-R’

[ example 1]

NI＝108.9℃；T_C<-20℃；η＝27.6mPa·s；Δn＝0.102；Δ＝-4.1；Vth＝2.27V；γ1＝187.9mPa·s.

Comparative example 1

The upper limit temperature of the nematic phase was adjusted equally without including the compound (1) of example 1.

NI＝109.0℃；T_C<-10℃；η＝28.4mPa·s；Δn＝0.099；Δ＝-4.1；Vth＝2.25V；γ1＝208.9mPa·s.

[ example 2]

NI＝107.9℃；T_C<-20℃；η＝26.7mPa·s；Δn＝0.113；Δ＝-3.4；Vth＝2.46V；γ1＝184.1mPa·s.

[ example 3]

NI＝102.0℃；T_C<-20℃；η＝26.7mPa·s；Δn＝0.111；Δ＝-3.8；Vth＝2.33V；γ1＝185.1mPa·s.

[ example 4]

NI＝102.8℃；T_C<-20℃；η＝22.3mPa·s；Δn＝0.120；Δ＝-3.6；Vth＝2.44V；γ1＝161.6mPa·s.

[ example 5]

NI＝104.5℃；T_C<-20℃；η＝26.6mPa·s；Δn＝0.119；Δ＝-3.2；Vth＝2.50V；γ1＝185.5mPa·s.

[ example 6]

NI＝101.2℃；T_C<-20℃；η＝22.9mPa·s；Δn＝0.110；Δ＝-3.2；Vth＝2.51V；γ1＝165.5mPa·s.

[ example 7]

NI＝101.2℃；T_C<-20℃；η＝22.0mPa·s；Δn＝0.118；Δ＝-3.2；Vth＝2.48V；γ1＝165.0mPa·s.

[ example 8]

NI＝104.8℃；T_C<-20℃；η＝26.7mPa·s；Δn＝0.120；Δ＝-3.6；Vth＝2.44V；γ1＝185.1mPa·s.

[ example 9]

NI＝107.0℃；T_C<-20℃；η＝23.3mPa·s；Δn＝0.121；Δ＝-3.3；Vth＝2.45V；γ1＝166.7mPa·s.

[ example 10]

NI＝106.6℃；T_C<-20℃；η＝25.8mPa·s；Δn＝0.107；Δ＝-3.3；Vth＝2.47V；γ1＝179.9mPa·s.

[ example 11]

NI＝103.2℃；T_C<-20℃；η＝21.9mPa·s；Δn＝0.115；Δ＝-3.1；Vth＝2.52V；γ1＝162.1mPa·s.

[ example 12]

NI＝101.6℃；T_C<-20℃；η＝27.7mPa·s；Δn＝0.127；Δ＝-3.8；Vth＝2.31V；γ1＝193.5mPa·s.

[ example 13]

NI＝103.6℃；T_C<-20℃；η＝27.8mPa·s；Δn＝0.114；Δ＝-3.7；Vth＝2.29V；γ1＝193.4mPa·s.

[ example 14]

NI＝102.1℃；T_C<-20℃；η＝26.1mPa·s；Δn＝0.119；Δ＝-4.0；Vth＝2.27V；γ1＝190.0mPa·s.

[ example 15]

NI＝102.9℃；T_C<-20℃；η＝22.1mPa·s；Δn＝0.119；Δ＝-3.8；Vth＝2.33V；γ1＝164.2mPa·s.

[ example 16]

NI＝102.5℃；T_C<-20℃；η＝23.7mPa·s；Δn＝0.110；Δ＝-3.6；Vth＝2.43V；γ1＝166.6mPa·s.

[ example 17]

NI＝100.4℃；T_C<-20℃；Δn＝0.112；Δ＝-3.3；Vth＝2.56V；γ1＝159.9mPa·s.

[ example 18]

NI＝100.3℃；T_C<-20℃；Δn＝0.113；Δ＝-3.3；Vth＝2.54V；γ1＝152.5mPa·s.

[ example 19]

NI＝100.0℃；T_C<-20℃；Δn＝0.112；Δ＝-3.3；Vth＝2.54V；γ1＝143.4mPa·s.

[ example 20]

NI＝100.3℃；T_C<-20℃；Δn＝0.112；Δ＝-3.3；Vth＝2.53V；γ1＝141.4mPa·s.

[ example 21]

NI＝100.2℃；T_C<-20℃；Δn＝0.112；Δ＝-3.4；Vth＝2.53V；γ1＝141.4mPa·s.

[ example 22]

NI＝100.8℃；T_C<-20℃；Δn＝0.113；Δ＝-3.5；Vth＝2.55V；γ1＝138.9mPa·s.

The lower limit temperature of the nematic phase of the composition of comparative example 1 was-10 ℃ and the rotational viscosity was 208.9 mPas. On the other hand, the lower limit temperature of the nematic phase of the composition of example 1 was-20 ℃ and the rotational viscosity was 187.9 mPas. As described above, the compositions of examples have a lower limit temperature of the nematic phase and a lower rotational viscosity than the compositions of comparative examples. Therefore, it can be concluded that the liquid crystal composition of the present invention has excellent characteristics.

[ industrial applicability ]

The liquid crystal composition of the present invention can be used in liquid crystal monitors, liquid crystal televisions, and the like.

Claims

1. A liquid crystal composition which contains at least one compound selected from the group consisting of compounds represented by the formula (1) as a component A and has a negative dielectric anisotropy:

2. The liquid crystal composition according to claim 1, wherein the proportion of the component a is in the range of 3 to 30 mass%.

3. The liquid crystal composition according to claim 1, which contains at least one compound selected from the compounds represented by formula (2) as component B:

in the formula (2), R³And R⁴Is hydrogen, alkyl group with 1 to 12 carbon atoms, alkoxy group with 1 to 12 carbon atoms, alkenyl group with 2 to 12 carbon atoms, alkenyloxy group with 2 to 12 carbon atoms, or at least one hydrogen atomFluorine or chlorine substituted alkyl having 1 to 12 carbon atoms; ring A and ring C are 1, 4-cyclohexylene, 1, 4-cyclohexenylene, tetrahydropyran-2, 5-diyl, 1, 4-phenylene in which at least one hydrogen is substituted by fluorine or chlorine, naphthalene-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine, or chroman-2, 6-diyl in which at least one hydrogen is substituted by fluorine or chlorine; ring B is 2, 3-difluoro-1, 4-phenylene, 2-chloro-3-fluoro-1, 4-phenylene, 2, 3-difluoro-5-methyl-1, 4-phenylene, 3,4, 5-trifluoronaphthalene-2, 6-diyl, 7, 8-difluorochromane-2, 6-diyl, 3,4,5, 6-tetrafluorofluorene-2, 7-diyl, 4, 6-difluorodibenzofuran-3, 7-diyl, 4, 6-difluorodibenzothiophene-3, 7-diyl, or 1,1,6, 7-tetrafluoroindan-2, 5-diyl; z⁴And Z⁵Is a single bond, ethylene, vinylidene, methyleneoxy or carbonyloxy; a is 0, 1,2 or 3, b is 0 or 1; and the sum of a and b is 3 or less.

4. The liquid crystal composition according to claim 1, which contains at least one compound selected from the group consisting of compounds represented by formulae (2-1) to (2-35) as the component B:

5. The liquid crystal composition according to claim 3, wherein the proportion of the component B is in the range of 10 to 90 mass%.

6. The liquid crystal composition according to claim 1, which contains at least one compound selected from the compounds represented by formula (3) as component C:

7. The liquid crystal composition according to claim 3, which contains at least one compound selected from the compounds represented by formula (3) as component C:

8. The liquid crystal composition according to claim 1, which contains at least one compound selected from the group consisting of compounds represented by formulae (3-1) to (3-9) as component C:

9. The liquid crystal composition according to claim 4, which contains at least one compound selected from the group consisting of compounds represented by formulae (3-1) to (3-9) as component C:

10. The liquid crystal composition according to claim 6, wherein the proportion of the component C is in the range of 10 to 90 mass%.

11. The liquid crystal composition according to claim 1, which contains at least one compound selected from polymerizable compounds represented by formula (4) as an additive X:

in formula (4), ring F and ring J are cyclohexyl, cyclohexenyl, phenyl, 1-naphthyl, 2-naphthyl, tetrahydropyran-2-yl, 1, 3-dioxane-2-yl, pyrimidine-2-yl or pyridin-2-yl, in which rings at least one hydrogen may be substituted by fluorine, chlorine, an alkyl group of carbon number 1 to 12, an alkoxy group of carbon number 1 to 12, or an alkyl group of carbon number 1 to 12 in which at least one hydrogen is substituted by fluorine or chlorine; ring G is 1, 4-cyclohexylene, 1, 4-cyclohexenylene, 1, 4-phenylene, naphthalene-1, 2-diyl, naphthalene-1, 3-diyl, naphthalene-1, 4-diyl, naphthalene-1, 5-diyl, naphthalene-1, 6-diyl, naphthalene-1, 7-diyl, naphthalene-1, 8-diyl, naphthalene-2, 3-diyl, naphthalene-2, 6-diyl, naphthalene-2, 7-diyl, tetrahydropyran-2, 5-diyl, 1, 3-dioxane-2, 5-diyl, pyrimidine-2, 5-diyl or pyridine-2, 5-diyl, and in these rings, at least one hydrogen may be substituted with fluorine, chlorine, an alkyl group having a carbon number of 1 to 12, an alkoxy group having a carbon number of 1 to 12, Or at least one hydrogen is substituted by a fluorine or chlorine substituted alkyl group of carbon number 1 to 12; z⁷And Z⁸Is a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂-may be substituted by-O-, -CO-, -COO-or-OCO-, at least one-CH₂CH₂-may be via-CH ═ CH-, -C (CH)₃)＝CH-、-CH＝C(CH₃) -or-C (CH)₃)＝C(CH₃) -substitution, of which at least one hydrogen may be substituted by fluorine or chlorine; p¹To P³Is a polymerizable group; sp¹To Sp³Is a single bond or an alkylene group having 1 to 10 carbon atoms, in which at least one-CH group₂At least one-CH which may be substituted by-O-, -COO-, -OCO-or-OCOO-)₂CH₂-may be substituted by-CH ═ CH-or-C ≡ C-, at least one of these groups being substituted by fluorine or chlorine; d is 0, 1 or 2; e. f and g are 0, 1,2, 3 or 4; and the sum of e, f and g is 1 or more.

12. The liquid crystal composition according to claim 11, wherein in formula (4), P is¹To P³Is a group selected from the polymerizable groups represented by the formulae (P-1) to (P-5):

in the formulae (P-1) to (P-5), M¹To M³Is hydrogen, fluorine, alkyl of carbon number 1 to 5, orAn alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted by fluorine or chlorine.

13. The liquid crystal composition according to claim 1, which contains at least one compound selected from polymerizable compounds represented by formulae (4-1) to (4-29) as an additive X:

in the formulae (P-1) to (P-3), M¹To M³Hydrogen, fluorine, an alkyl group having 1 to 5 carbon atoms, or an alkyl group having 1 to 5 carbon atoms in which at least one hydrogen is substituted with fluorine or chlorine.

14. The liquid crystal composition according to claim 11, wherein the proportion of the additive X is in the range of 0.03 to 10 mass%.

15. A liquid crystal display element comprising the liquid crystal composition according to claim 1.

16. The liquid crystal display device according to claim 15, wherein the liquid crystal display device is operated in an in-plane switching mode, a vertical alignment mode, a fringe field switching mode or an electric field induced photo-responsive alignment mode, and the liquid crystal display device is driven in an active matrix mode.

17. A polymer-stabilized alignment type liquid crystal display element comprising the liquid crystal composition according to claim 11, wherein the polymerizable compound in the liquid crystal composition is polymerized.

18. Use of a liquid crystal composition according to claim 1 in a liquid crystal display element.

19. Use of a liquid crystal composition according to claim 11 in a liquid crystal display element of polymer stabilized alignment type.